BURNER AND COOKING APPLIANCE HAVING BURNER

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority to Korean Patent Application No. 10-2023-0172529, filed in Korea on Dec. 1, 2023, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND
1. Field

A burner and a cooking appliance having a burner are disclosed herein.

2. Background

Cooking appliances are a type of home appliance used to cook food or other items (hereinafter, collectively “food”) and an appliance generally provided in a kitchen space. The cooking appliances may be classified in various ways according to a heat source, form, and type of fuel. When the cooking appliances are classified according to a form in which food is cooked, the cooking appliances may be classified into an open type and a sealed type according to a form of a space in which the food is placed. Sealed-type cooking appliances include ovens and microwave ovens, for example, and open type cooking appliances include cooktops and griddles, for example.

The sealed-type cooking appliances shield the space in which food is placed with doors and heat the shielded space to cook the food. The sealed type cooking appliance includes a cooking chamber in which the food is placed and which shields the food when it is cooked.

Among the sealed type cooking appliances, a cooking appliance using a gas burner as a heat source may include a burner to heat food inside of the cooking chamber. For example, a burner may be provided behind the cooking chamber to heat air. A convection fan may be provided behind the burner to transfer air heated by the burner evenly to the cooking chamber.

The conventional burner may have flame holes formed at opposite side portions of the burner to improve firepower. As described above, the burner with the flame holes arranged at the opposite side portions may heat a wider area in the cooking chamber.

However, the burner with the flame holes at the opposite side portions should be arranged at a central portion, such as a central portion of the bottom or a central portion of the rear surface of the cooking chamber to evenly heat the cooking chamber. However, as described above, when the burner is arranged at the central portion of the cooking chamber, interference may easily occur between the burner and surrounding components, and there is a limitation in the structure and arrangement of the components around the surrounding burner.

To solve this problem, a burner bent into a U or L form may be used to be arranged around edges of the cooking chamber. However, the burner bent as described above has disadvantages of processing difficulty and high manufacturing costs.

Further, the conventional burner has flame holes arranged in multiple columns to improve firepower. However, an interval among the flame holes arranged in the multiple columns is narrow, so secondary air is not sufficiently supplied into the flame holes. When the secondary air is not sufficiently supplied, incomplete combustion occurs because there is not enough air for combustion inside of the flame, and a flame length increases, which is a problem. Furthermore, when enough secondary air is not supplied, a yellow tip occurs, and soot and harmful gases (CO, NOX, SOX) are generated, which is problematic.

Recently developed cooking appliances have a convection fan provided behind the burner and air heated by the burner is transferred evenly throughout the cooking chamber. When the convection fan is operated, air is suctioned toward the convection fan, and a flame of the burner may face a rear wall surface of the cooking chamber. The wall of the cooking chamber may be overheated and a coating layer, such as an enamel layer, for example, may be damaged due to heat. To solve this problem, a separate protecting means, such as a burner reflector, to protect a wall surface of the cooking chamber from the heat of the burner is necessarily provided in the cooking appliance.

Further, a flow of the air suctioned by the convection fan may make the flame of the burner unstable. This problem may be solved by providing a separate stabilizer between the burner and the convection fan and preventing a flow of air caused by the convection fan from directly affecting the burner.

However, the existing cooking appliance needs a separate component, such as a burner reflector and a stabilizer, so the number of components and the manufacturing costs thereof increase. Further, it is difficult to design the cooking appliance due to the complexity of a heating device, which are problems.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein:

FIG. 1 is a perspective view of a cooking appliance according to an embodiment;

FIG. 2 is a perspective view of an inside space of a cooking chamber of an oven according to an embodiment;

FIG. 3 is a front view of the inside space of the cooking chamber of the oven without a cook-top and a drawer according to an embodiment;

FIG. 4 is a rear view of a rear side of the oven without the cook-top and the drawer according to an embodiment;

FIG. 5 is another rear view of the view of the oven of FIG. 4 without a cover plate;

FIG. 6 is an exploded perspective view of components of the oven according to an embodiment;

FIG. 7 is an exploded perspective view of a fan cover, a partition cover, a fan device, and a heating device of the oven according to an embodiment;

FIG. 8 is a front cross-sectional view taken by cutting a portion of the oven to expose the fan device and the heating device according to an embodiment;

FIG. 9 is a cross-sectional view, taken along line IX-IX′ of FIG. 2;

FIG. 10 is a cross-sectional view of a side structure of the oven and the drawer according to an embodiment;

FIG. 11 is an enlarged side view of a circulation device and the heating device of FIG. 10;

FIG. 12 is an enlarged perspective view of the circulation device and the heating device of FIG. 10;

FIG. 13 is a perspective view of the heating device according to an embodiment;

FIG. 14 is a perspective view of the heating device according to an embodiment at a different angle from FIG. 13;

FIG. 15 is a front view of a burner of the heating device according to an embodiment;

FIG. 16 is a plan view of the heating device according to an embodiment;

FIG. 17 is a rear view of the heating device according to an embodiment;

FIG. 18 is a cross-sectional view, taken along line XVIII-XVIII′ of FIG. 3;

FIG. 19 is a perspective view of the cross-sectional view of FIG. 18 at a different angle;

FIG. 20 is a perspective view of the cross-sectional view of FIG. 18 at a different angle from FIG. 19

FIG. 21 is a cross-sectional view, taken along line XXI-XXI of FIG. 3;

FIG. 22 is a perspective view of a rear lower structure of the oven according to an embodiment;

FIG. 23 is a cross-sectional view, taken along line XXIII-XXIII′ of FIG. 22;

FIG. 24 is a plan view of a burner according to an embodiment;

FIG. 25 is an enlarged view of a structure of a flame hole portion of the burner according to an embodiment;

FIG. 26 is a concept view of a secondary air flowing into the flame hole portion of the burner according to an embodiment;

FIG. 27 is a cross-sectional view of an internal structure of the burner according to an embodiment;

FIG. 28 is a graph illustrating change in CO generation and initial combustion time according to an angle of the flame hole portion of the burner according to an embodiment;

FIG. 29 is a plan view of a burner according to another embodiment;

FIG. 30 is a concept view of a secondary air flowing into a flame hole portion of the burner according to an embodiment; and

FIG. 31 is a cross-sectional view of an internal structure of the burner according to an embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described with reference to the illustrative drawings. Wherever possible, the same or like reference numerals will be used throughout the drawings and the description to refer to the same or like elements or parts. Further, it is to be noted that, when the description of functions and configuration of conventional elements related to the embodiments may make the gist unclear, description of those elements has been omitted.

Embodiments relate to a cooking appliance. The cooking appliance may include a cooking chamber S1 therein. The cooking appliance may be a sealed cooking appliance in which the cooking chamber S1 is opened and closed by a door 50. Among terms described hereinafter, “a front side” may be a direction toward a user when the user is located in front of the cooking appliance. Referring to FIG. 1, an X-axial direction may be directed to the front side. A Y-axial direction may be a leftward-rightward width or lateral direction of the cooking chamber S1. A Z-axial direction may be a heightwise direction of the cooking chamber S1. Hereinafter, the cooking appliance will be described based on these directions.

As shown in FIGS. 1 and 2, a frame of the cooking appliance may be formed by an outer case 10. The outer case 10 may be considered a portion exposed outside of the cooking appliance. The outer case 10 may have a roughly hexahedral structure or shape. An oven, which will be described hereinafter, may be disposed inside of the outer case 10.

In this embodiment, a cook-top 30 may be disposed at an upper portion of the cooking appliance, and a drawer 40 may be disposed at a lower portion thereof. The cook-top 30 may form an upper portion of the outer case 10. The drawer 40 may form a lower portion of the outer case 10. The oven may be disposed between the cook-top 30 and the drawer 40. As another example, the cook-top 30 or the drawer 40 may be omitted or both may be omitted.

The outer case 10 may have a roughly cuboid shape. The outer case 10 may be made of a material having a predetermined strength to protect multiple components installed inside of the outer case 10. The oven may be disposed inside of the outer case 10. The oven may be shielded by the outer case 10 and the door 50.

As shown in FIG. 2, the outer case 10 may include a front panel 11, a side panel 12, and a rear panel 20. The front panel 11 is a portion exposed when the door 50 is opened and may form a front surface of a frame 60. The side panel 12 may cover a left/right or first/second lateral surface of the frame 60. Referring to FIG. 10, a lower panel 17 of the outer case 10 may be provided at a lower portion of the drawer 40.

The front panel 11 may be coupled to a front surface of the frame 60, which will be described hereinafter. The front panel 11 may be disposed around edges of an opening of the cooking chamber S1 provided inside of the frame 60. When the door 50 is closed, a rear surface of the door 50 may be brought into close contact with the front panel 11.

The side panel 12 may be disposed on or at either side surface of the frame 60. The side panel 12 may be provided higher than a side surface of the frame 60. Accordingly, an electric chamber 13 may be provided between two side panels 12. The electric chamber 13 may provide a space in which electronic components are located, between the cook-top 30 and the oven. A control panel 55 may be located on or at a front surface of the electric chamber 13. The control panel 55 may shield the front surface of the electric chamber 13.

The rear panel 20 may be disposed behind the frame 60. The rear panel 20 may be coupled to the two side panels 12. The rear panel 20 may be spaced apart from a rear surface of the frame 60. Accordingly, the rear panel 20 and the rear surface of the frame 60 may be spaced apart from each other. This spacing may form an insulation space S4 (referring to FIG. 10) filled with an insulator. This structure will be described hereinafter.

FIG. 4 is a rear view of the rear panel 20. Multiple holes may be provided on a surface of the rear panel 20. A motor (not illustrated) may be installed at some holes 25a of the multiple holes to lock the door 50. Another part or portion 25b of the holes may be connected to a pipe to supply fuel for a broil burner H (referring to FIG. 8) disposed at an upper portion of the cooking chamber S1, or may be a hole for installing a thermistor (not illustrated).

The rear panel 20 may include a panel opening 23. The panel opening 23 may be formed through the rear panel 20. The panel opening 23 may expose a heating device 100 provided inside of the outer case 10. The panel opening 23 may be provided at a height equal to a height of the heating device 100. The panel opening 23 may be provided lower than a bottom of the frame 60.

The panel opening 23 may be shielded by a shielding cover 28. FIG. 4 illustrates the panel opening 23 shielded by the shielding cover 28. In this embodiment, the shielding cover 28 does not fully shield the panel opening 23 and may allow a part or portion of the panel opening 23 to be open. Through the open portion, a part or portion of the heating device 100 including a nozzle holder 127 to spray gas to the burner 120 may be exposed.

When the shielding cover 28 is removed as illustrated in FIG. 5, more of the heating device 100 may be exposed rearward. Most of the burner 120 of the heating device 100 may be exposed through the panel opening 23. A worker may remove the shielding cover 28 and access the heating device 100 to maintain the heating device 100. Further, the shielding cover 28 may be removed, and the burner 120 may be assembled to the heating device 100.

As described hereinafter, a burner case 110 may include a chamber opening 118 connected to the panel opening 23, and when the shielding cover 28 is removed, the worker may directly access a combustion chamber S5 which is an inside space of the burner case 110. As another example, the shielding cover 28 may be omitted. As another example, the shielding cover 28 may be coupled to the burner case 110 but not to the rear panel 20. The shielding cover 28 will be described hereinafter.

As shown in FIG. 1, the cook-top 30 may include multiple cook-top burners 35. The cook-top burners 35 may cook food by heating a container in which food is contained or directly cook food with a flame F (referring to FIG. 18) generated by burning gas. Reference numeral 32 indicates a top grate on which a container, for example, may be placed. As another example, the cook-top 30 may include one or more electric heaters. As another example, the cook-top 30 may include an induction heating (IH) burner that uses induced current caused by a magnetic field as a heat source. As another example, the cook-top 30 may be omitted.

The drawer 40 may include a drawer handle 45. The drawer 40 may slide forward and rearward from the outer case 10. The drawer 40 may keep a container containing food warm at a predetermined temperature. FIG. 10 illustrates a storage space 43 provided inside of the drawer 40 to store a container, for example. As another example, the drawer 40 may be omitted.

As shown in FIG. 1, the control panel 55 may be arranged in front of the cook-top 30. The control panel 55 may include a nob 57 to control the cook-top 30. The control panel 55 may include an operating part or portion 59 to control the oven and the drawer 40. The operating portion 59 may include a touch panel to display a state of the cooking appliance.

The door 50 may shield a front side of the cooking chamber S1. The door 50 may be operated in a kind of pull-down manner in which an upper end of the door is vertically swung about a lower end. As another example, the door 50 may be operated in a side swing manner in which the door is opened sideways. The door 50 may have structure that enables the cooking chamber S1 to be visible therethrough. For example, a front surface 52 of the door 50 may have a glass panel structure, and a user may observe the cooking chamber S1 through the door 50. As another example, the cooking chamber S1 may not be visible through the door 50 from outside. Reference numeral 53 indicates a handle to open and close the door 50.

Referring to FIG. 2, a bottom surface of the electric chamber 13 may form an upper surface portion of the frame 60. The electric chamber 13 may include an exhaust duct 68. The exhaust duct 68 may be provided to discharge combustion gas out of the cooking appliance, the combustion gas being produced in the process of cooking food inside of the cooking chamber S1. A lower end of the exhaust duct 68 may be connected to an outlet port 64 open in the upper surface portion of the frame 60, and an upper end thereof may be disposed at an upper portion of a rear surface of the cooking appliance.

With reference to FIG. 3, the frame 60 may have a roughly hexahedral structure. The cooking chamber S1 may be provided inside of the frame 60. The cooking chamber S1 may have a roughly hexahedral structure similar to the frame 60. The frame 60 may be opened and closed by the outer case 10 and the door 50. Most of the surface of the frame 60 excluding the cooking chamber S1 may be covered by the outer case 10.

The frame 60 may include a frame lower surface 61 forming a bottom surface of the cooking chamber S1, a frame side surface 62 forming a side surface of the cooking chamber S1, a frame upper surface 63 forming an upper surface of the cooking chamber S1, and a frame rear surface 65 forming a rear surface of the cooking chamber S1. In addition, a front surface of the frame 60 may be open, and the cooking chamber S1 may be exposed.

In this embodiment, a circulation device C, which will be described hereinafter, may be disposed inside of the frame 60. The inside space of the frame 60 may be a space surrounded by the frame lower surface 61, the frame side surface 62, the frame upper surface 63, and the frame rear surface 65. The cooking chamber S1 may also be provided inside of the frame 60. The cooking chamber S1 may be provided in front of the circulation device C.

The heating device 100, which will be described hereinafter, may be arranged outside of the frame 60. An outside space of the frame 60 may be the outside space of the space surrounded by the frame lower surface 61, the frame side surface 62, the frame upper surface 63, and the frame rear surface 65. As described above, in this embodiment, the circulation device C and the heating device 100 may be arranged inside and outside of the frame 60.

Referring to FIG. 3, when the door 50 is opened, a cover plate 80 of the circulation device C, which will be described hereinafter, may be exposed inside of the cooking chamber S1. The cover plate 80 may be disposed in front of the frame rear surface 65 forming the rear surface of the cooking chamber S1. The cover plate 80 may be coupled to the frame rear surface 65 and may cover a partition plate 70 and a circulation fan 93. As described above, the circulation device C may be arranged inside of the cooking chamber S1 and may circulate air in the cooking chamber S1. For reference, a suction hole 84 of the cover plate 80 through which internal air of the cooking chamber S1 is suctioned, and second discharge holes 85 are provided to discharge heated air into the cooking chamber S1.

As illustrated in FIG. 3, the heating device 100 may be arranged at a lower portion of the frame 60. More specifically, the heating device 100 may be arranged lower than the frame lower surface 61. The circulation device C may be arranged inside of the cooking chamber S1, but the heating device 100 is arranged at the lower portion of the frame 60 which is outside of the cooking chamber S1. Referring to FIG. 10, the heating device 100 may be arranged between the frame lower surface 61 and a drawer cover 47 forming an upper surface of the drawer 40. When the drawer 40 is omitted, the heating device 100 may be arranged between the frame lower surface 61 and the lower panel 17.

FIG. 6 is an exploded view of the rear panel 20, the frame 60, the circulation device C, and the heating device 100. The circulation device C may suction internal air of the cooking chamber S1 and mix the air with high temperature air supplied from the heating device 100. The circulation device C may discharge the mixed air into the cooking chamber S1. These processes may be performed simultaneously and continuously, and the internal air of the cooking chamber S1 may be circulated.

The circulation device C and the heating device 100 may be connected to each other via a connection passage 61a (referring to FIG. 11) provided in the frame 60. In this embodiment, the connection passage 61a is formed through the frame lower surface 61. The circulation device C may be arranged above the connection passage 61a, and the heating device 100 may be arranged below the connection passage 61a. The connection passage 61a may be provided at a rear portion of the frame lower surface 61, which is close to the frame rear surface 65. As another example, the connection passage 61a may be provided at either side portion of the frame lower surface 61, which is close to the frame side surface 62. As another example, the connection passage 61a may be provided in the frame side surface 62. In this case, the heating device 100 may be arranged at a position opposite to the circulation device C with the frame side surface 62 located therebetween.

The circulation device C may be arranged inside of the cooking chamber S1. In this embodiment, the circulation device C is arranged in front of the rear panel 20. The circulation device C may be positioned at a rear side of the cooking chamber S1 and suction air from the front side of the cooking chamber S1 rearward (referring to X-axial direction in FIG. 1), and then discharge the air sideways. The circulation device C may include the circulation fan 93 to provide suction and discharge functions. However, as described hereinafter, in this embodiment, the heating device 100 may cause heated air to rise by natural draft. Therefore, even when the circulation fan 93 does not operate, heated air may be supplied to the cooking chamber S1.

Referring to FIG. 9, a circulation chamber SA may be provided inside of the circulation device C. The circulation chamber SA may be connected to the cooking chamber S1. In the circulation chamber SA, air introduced from the cooking chamber S1 may exchange heat with air heated by the heating device 100. The heat-exchanged air may be discharged back into the cooking chamber S1.

The circulation chamber SA may form an upper flow path connected to the cooking chamber S1. The upper flow path may be a path through which air is suctioned from the cooking chamber S1 and discharged back to the cooking chamber S1. The combustion chamber S5 inside of the heating device 100, which will be described hereinafter, may form a lower flow path that transfers air heated by the burner 120 to the upper flow path. The upper flow path and the lower flow path may be connected to each other in a heightwise direction of the frame 60 via the connection passage 61a formed in the frame lower surface 61. The heightwise direction of the frame 60 is a vertical direction based on the drawing and is a Z-axial direction in FIG. 1. This flow path structure will be described hereinafter.

The circulation device C may include the partition plate 70 and the cover plate 80. The cover plate 80 may be arranged in front of the rear panel 20. The partition plate 70 may be arranged between the cover plate 80 and the rear panel 20. The partition plate 70 and the cover plate 80 may have similar shapes, and a size of the cover plate 80 may be larger than a size of the partition plate 70. The cover plate 80 may be coupled to the frame rear surface 65 while covering and shielding the partition plate 70.

The partition plate 70 may be made of a metal material, and a partition body 71 may form a frame of the partition plate 70. The partition body 71 may have a roughly flat structure. A partition bending part or portion 72 may be provided at an edge of the partition body 71. The partition plate 70 may have a frontward-rearward directional thickness by the partition bending portion 72. A partition coupling end 73 provided at an end of the partition bending portion 72 may be coupled to the frame rear surface 65 while overlapping with a cover coupling end 83 of the cover plate 80.

A communication hole 74 may be open in the partition body 71. The communication hole 74 may be formed through the partition body 71 in a frontward-rearward direction. The communication hole 74 may have a roughly circular structure. The communication hole 74 may be connected to the suction hole 84 of the cover plate 80. The communication hole 74 may be provided at a position corresponding to a position behind the suction hole 84. The circulation fan 93 may be arranged in the communication hole 74, so the communication hole 74 may be considered a fan installation space.

Multiple first discharge holes 75 may be formed in the partition bending portion 72. The first discharge holes 75 may be formed through the partition bending portion 72. The first discharge holes 75 may be open in directions different from an open direction of the communication hole 74. In this embodiment, the first discharge holes 75 may be open sideways. The first discharge holes 75 may be connected to the second discharge holes 85 of the cover plate 80. The air heated by the heating device 100 may be supplied into the cooking chamber S1 via the first discharge holes 75 and the second discharge holes 85.

The partition plate 70 may partition a space between the cover plate 80 and the frame rear surface 65. The circulation chamber SA may be provided between the partition plate 70 and the frame rear surface 65. The circulation chamber SA may be divided into two parts or portions by the partition plate 70. More specifically, as illustrated in FIG. 9, the circulation chamber SA may be divided into a front heating chamber S2 closer to the cooking chamber S1 on the basis of the partition plate 70, and a rear discharge chamber S3. The heating chamber S2 may be a space in which air heated by the heating device 100 and air suctioned from the cooking chamber S1 are mixed together. The discharge chamber S3 may be a space in which the air mixed in the heating chamber S2 is discharged back to the cooking chamber S1. Of course, a part or portion of the air in the cooking chamber S1 may flow directly into the discharge chamber S3. However, when the circulation fan 93 is operated, most of the air in the discharge chamber S3 may be discharged to the cooking chamber S1.

The cover plate 80 may be made of a metal material, and a cover body 81 may form a frame of the cover plate 80. The cover body 81 may have a roughly flat structure. A cover bent part or portion 82 may be provided at an edge of the cover body 81. The cover plate 80 may have a frontward-rearward directional thickness by the cover bent portion 82. The cover coupling end 83 provided at the end of the cover bent portion 82 may be coupled to the frame rear surface 65 while overlapping with the partition coupling end 73 of the partition plate 70.

A lower end of the cover plate 80 and a lower end of the partition plate 70 may be respectively supported by the frame 60. The structure in which the lower end of the cover plate 80 and the lower end of the partition plate 70 are supported by the frame 60 will be described hereinafter with a structure in which the heating device 100 is supported by the frame 60.

The cover plate 80 may be coupled to the frame rear surface 65 while covering the partition plate 70, so the partition plate 70 may be shielded by the cover plate 80. As illustrated in FIG. 3, when the cooking chamber S1 is viewed from the front, only the cover plate 80 is exposed.

The suction hole 84 may be open in the cover body 81. The suction hole 84 may be formed through the cover body 81 in the frontward-rearward direction. The suction hole 84 may be a hole for suctioning air in the cooking chamber S1. The air suctioned through the suction hole 84 may flow into the heating chamber S2. In this embodiment, the suction hole 84 has a roughly circular structure. The suction hole 84 may have a louver form, and an inside part or portion of the suction hole 84, that is, most of the structure of the partition plate 70 may be shielded. As another example, the suction hole 84 may be a simple circular hole similar to the communication hole 74 or may have different forms other than a circular form.

The suction hole 84 may be connected to the communication hole 74 of the partition plate 70. The suction hole 84 may be provided at a position corresponding to a position in front of the communication hole 74. The circulation fan 93 may be arranged behind the suction hole 84, and air may be suctioned through the suction hole 84.

The cover bent portion 82 may include the multiple second discharge holes 85. The second discharge holes 85 may be formed through the cover bent portion 82. Each of the second discharge holes 85 may be open in directions different from a direction in which the suction hole 84 is open. In this embodiment, the second discharge holes 85 are open sideways. The second discharge holes 85 may be connected to the first discharge holes 75 of the partition plate 70. The air heated by the heating device 100 may be supplied into the cooking chamber S1 via the first discharge holes 75 and the second discharge holes 85.

In this embodiment, the first discharge holes 75 and the second discharge holes 85 may be respectively provided in side surfaces and inclined surfaces of the partition bending portion 72 and the cover bent portion 82. As another example, the first discharge holes 75 and the second discharge holes 85 may be respectively provided in upper surfaces and lower surfaces of the partition bending portion 72 and the cover bent portion 82.

FIG. 8 illustrates the cover plate 80 a part or portion of which is cut off. The circulation fan 93 may be provided inside of the cover plate 80. When the circulation fan 93 is operated, external air may be induced toward the heating device 100 (direction of arrow {circle around (1)}). The heated air passing through the heating device 100 may flow upward toward the circulation device C (direction of arrow {circle around (2)}). Due to a suction force of the circulation fan 93, air transferred toward the circulation fan 93 (direction of arrow {circle around (3)}) may be discharged outward by rotation of the circulation fan 93 (direction of arrow {circle around (4)}), that is, discharged into the cooking chamber S1.

As described above, in this embodiment, the heating device 100 may be arranged at a lower portion of the circulation device C. Air heated by the heating device 100 may (i) be caused to rise by or flow upward due to the suction force of the circulation fan 93, and (ii) may be caused to rise or flow upward by natural draft. In other words, when a temperature of air is increased by the heating device 100, a volume of the air expands, a density is lowered, and a buoyant force increases, so the air rises or flows upward. Specific structure related to the circulation of air will be described hereinafter.

The circulation fan 93 may be coupled to a fan motor 91 to form a fan assembly 90. The fan assembly 90 may include the fan motor 91, the circulation fan 93, a rotational shaft 92, and a motor cooling fan 95. The fan motor 91 and the motor cooling fan 95 may be arranged outside of the outer case 10. More specifically, the fan motor 91 and the motor cooling fan 95 may be arranged on a rear surface of the rear panel 20 forming the outer case 10. Referring to FIG. 5, the fan motor 91 arranged at the rear panel 20 and exposed rearward is illustrated.

As illustrated in FIG. 7, the fan motor 91 may include a motor central part or portion 91a at a central portion thereof, and the rotational shaft 92 may be coupled to the motor central portion 91a. The fan motor 91 includes a fan bracket 91b, and the fan bracket 91b may be fixed to the rear panel 20. The motor cooling fan 95 may be rotated coaxially with the circulation fan 93 by the rotational shaft 92. The motor cooling fan 95 may cool the fan motor 91. As another example, the motor cooling fan 95 may be omitted.

As illustrated in FIG. 8, the circulation fan 93 may be arranged in front of the frame rear surface 65. The circulation fan 93 may be arranged opposite to the motor cooling fan 95 and the fan motor 91, with the frame rear surface 65 and the rear panel 20 located therebetween. The rotational shaft 92 may pass through a panel through hole 24 of the rear panel 20 and a shaft through hole (not illustrated) of the frame rear surface 65, and then connect the circulation fan 93 to the fan motor 91.

As illustrated in FIG. 9, in this embodiment, the circulation fan 93 may be arranged inside of the circulation chamber SA. The circulation fan 93 may be considered a part or portion of the circulation device C. Further, an entire part or portion of the fan assembly 90 may be considered a part or portion of the circulation device C. As another example, the fan assembly 90 may not be arranged at the rear panel 20 and may be arranged at the side panel 12 or the upper panel. As another example, the fan assembly 90 may be omitted.

The heating device 100 may be configured to heat air. The heating device 100 may be configured (i) to heat air introduced from the outside space, and (ii) to heat air inside of the cooking chamber S1. In this embodiment, the heating device 100 may be arranged outside of the cooking chamber S1, and mostly air introduced from the outside space is heated. However, when a portion of the internal air of the cooking chamber S1 flows into the heating device 100, the heating device 100 may heat the internal air.

The heating device 100 may be arranged outside of the frame 60. In this embodiment, the heating device 100 may be arranged below the frame lower surface 61. Referring to FIG. 10, the heating device 100 may be arranged between the frame lower surface 61 and the lower panel 17. More specifically, the heating device 100 may extend in one direction along a rear edge of the lower portion of the frame 60.

Referring to FIG. 10, an installation space IS may be provided between the frame lower surface 61 and the lower panel 17. The heating device 100 may be arranged inside of the installation space IS. The heating device 100 may be arranged at a rear portion of the installation space IS, that is, at a position close to the rear panel 20.

As described above, when the heating device 100 is arranged outside of the frame 60, intrusion of the heating device 100 into the cooking chamber S1 is prevented. Therefore, the space in the cooking chamber S1 is not reduced due to the heating device 100 and may be widened. More specifically, in this embodiment, a heating component, such as the burner 120, is omitted in the circulation device C, and a component, such as a burner reflector for assisting a heating component, is omitted. Therefore, a rear space of the cooking chamber S1 may be widened.

The installation space IS is an empty space. Therefore, even when the heating device 100 is arranged therein, an entire size of the cooking appliance is prevented from increasing. Further, the installation space IS may be an external air introduction part or portion into which external air is introduced. Accordingly, air introduced through the installation space IS may cool a lower surface of the heating device 100 during the introduction process. This structure will be described hereinafter.

Referring to FIG. 10, the burner 120 provided at the heating device 100 may generate a flame in a forward direction, that is, generate a flame in a direction toward the door 50 (direction of arrow {circle around (1)}). Herein, a direction in which the burner 120 generates the flame may be a first direction. In addition, the circulation device C and the heating device 100 may be arranged in a second direction (direction of arrow {circle around (2)}) different from the first direction. Therefore, the flame produced by the heating device 100 may heat air in a front space in the heating device 100 (the combustion chamber S5, referring to FIG. 18), and the heated air may move upward to the heating chamber S2. In this embodiment, the first direction and the second direction may be formed to be orthogonal to each other. As another example, the first direction may be a direction inclined upward from the horizontal direction.

Referring to FIG. 11, an air flow caused by the circulation device C and the heating device 100 may be indicated by arrows. First, in the air flow caused by the circulation device C, when the circulation fan 93 is operated, the air in the cooking chamber S1 may be suctioned in a direction toward the circulation fan 93 (direction of arrow {circle around (1)}).

At the same time, air in the combustion chamber S5 heated by the heating device 100 is caused to rise or flows upward in the direction of the heating chamber S2 of the circulation device C (direction of arrow {circle around (2)}). The heated air caused to rise or flowing upward to the heating chamber S2 may be mixed with the air that is suctioned from the cooking chamber S1. At this point, a temperature of the air suctioned from the cooking chamber S1 is relatively low, and a temperature of the air caused to rise or flowing upward from the heating device 100 is relatively high as the air is heated. When the two types of air are mixed and exchange heat with each other, the temperature of the mixed air may be higher than the temperature of the air introduced from the cooking chamber S1.

As described above, the air heated by the heating device 100 may rise or flow upward due to natural draft in the direction toward the heating chamber S2 of the circulation device C (direction of arrow {circle around (2)}). Therefore, even when the circulation fan 93 is not operated, the heated air may be supplied to the cooking chamber S1.

The mixed air passes through the communication hole 74 of the partition plate 70 and moves to the discharge chamber S3 (direction of arrow {circle around (3)}). The air entering the discharge chamber S3 may be discharged back to the cooking chamber S1 through the first discharge holes 75 and the second discharge holes 85 connected to each other (direction of arrow {circle around (4)}). At this point, the discharge of the mixed air into the cooking chamber S1 may be achieved by operation of the circulation fan 93 but may be achieved by a pressure difference due to the air rising from the combustion chamber S5 due to natural draft.

When the burner 120 is operated to heat the air of the combustion chamber S5, the heating device 100 may be overheated. Further, the frame 60 arranged at an upper portion of the heating device 100 may be deformed by high temperature heat or an enamel coating layer of the frame 60 may be damaged. To prevent the above problem, in this embodiment, the heating device 100 and the frame 60 may be cooled using external air.

Referring to FIG. 11, external air passing through a lower part or portion of the heating device 100 may be indicated by arrow {circle around (5)}. The external air may move along a lower surface of the heating device 100. The external air may be a secondary air supplied to the burner 120 and may perform a cooling function.

The external air cooling the lower surface of the heating device 100 while passing through the lower surface of the heating device 100 may be introduced into the heating device 100 (direction of arrow {circle around (6)}). More specifically, as illustrated in the enlarged view of FIG. 11, air may be introduced into the heating device 100 through a second inlet IP2, that is, a gap formed between the heating device 100 and the rear panel 20.

Some of the air may be heated by the heating device 100 to move to the heating chamber S2, and another part or portion may move along cooling flow path CP1, CP2 (referring to FIG. 18) partitioned by a flow path guide 130 of the heating device 100. More specifically, a part or portion of the air for cooling moves along a lower portion of the burner 120 inside of the heating device 100 and then rises or flows upward through a space (cooling flow path) CP1 formed by spacers 111a (referring to FIG. 13). In this process, the lower surface of the heating device 100, and a front surface of the heating device 100, and the lower portion of the frame 60 may be prevented from being overheated (referring to direction of arrow {circle around (7)}).

Another part or portion of the air for cooling may move along an upper portion of the burner 120 and may prevent overheating of the upper surface of the heating device 100, a flame guide 140, and the lower portion of the frame 60 (referring to direction of arrow {circle around (8)}). The air flowing into the upper portion of the cooking chamber S1 (arrow {circle around (8)}) may be introduced through another second inlet IP2 provided at the upper portion of the heating device 100 (referring to arrow {circle around (5)}′ of FIG. 19). This structure will be described hereinafter.

Referring to FIG. 12, the internal structure of the circulation device C and the heating device 100 is illustrated. Air suctioned through the suction hole 84 of the cover plate 80 may enter the heating chamber S2 (direction of arrow {circle around (1)}), and the heating chamber S2 may be filled with air heated by the heating device 100. Accordingly, the air of the cooking chamber S1 may be heated in the process in which the air moves toward the communication hole 74 while passing through the suction hole 84. The motor cooling fan 95 of the fan assembly 90 may rotate with the circulation fan 93, discharge air toward the fan motor 91 (direction of arrow {circle around (2)}), and cool the fan motor 91.

A flame generated by the burner 120 may heat air in the combustion chamber S5. A generation direction of the flame generated by the burner 120 may be guided by the flame guide 140, which will be described hereinafter. Arrow {circle around (3)} indicates a direction in which the flame is guided by the flame guide 140. The flame may be naturally directed to the heating chamber S2. More specifically, the air in the combustion chamber S5 heated by the heat of combustion may pass through a flow path formed by the flame guide 140 and the flow path guide 130, which will be described hereinafter. In addition, the air rising or flowing upward along the flow path may pass through the connection passage 61a provided on the frame lower surface 61 and move to the heating chamber S2.

In this embodiment, a frontward-rearward length L2 of the heating device 100 is longer than a frontward-rearward length L1 of the lower portion of the circulation device C. The frontward-rearward direction is a direction from the door 50 toward the frame rear surface 65. In other words, the frontward-rearward direction is a direction in which the cover plate 80 and the partition plate 70 are coupled to each other, and may be considered a shaft direction of the rotational shaft 92.

When the frontward-rearward length of the heating device 100 is longer than the frontward-rearward length of the lower portion of the circulation device C, an upper area of the circulation device C may be entirely included in an upper area of the heating device 100. As illustrated in FIG. 12, an entire lower portion of the circulation device C may be overlapped with the upper portion of the heating device 100. Accordingly, the frontward-rearward length of the circulation device C and the heating device 100 may be the frontward-rearward length of the heating device 100. Therefore, in the cooking appliance, the frontward-rearward length occupied by the circulation device C and the heating device 100 may be minimized.

Further, when the entire lower portion of the circulation device C overlaps with the upper portion of the heating device 100, a transfer path between the combustion chamber S5 and the circulation chamber SA may be minimized. When the transfer path between the combustion chamber S5 and the circulation chamber SA is shortened, heat loss may be reduced, and an efficiency of the cooking appliance may increase. In addition, the discharge chamber S3 may be arranged to overlap with the combustion chamber S5, so heat of the combustion chamber S5 may be conducted to the discharge chamber S3. The conducted heat heats air in the discharge chamber S3 to increase heat efficiency of the cooking appliance.

In this embodiment, the upper portion of the heating device 100 overlaps with the lower portion of the circulation device C, and may not overlap with the bottom of the cooking chamber S1. This prevents heat in the heating device 100 from directly heating the bottom surface of the cooking chamber S1 and simultaneously enables heat of the heating device 100 to be focused on the circulation device C.

Referring to FIG. 11, based on an extension direction of a flow path in which the combustion chamber S5 and the heating chamber S2 are connected to each other, the burner 120 may be arranged in a position that deviates from a range in which the burner overlaps with the heating chamber S2. The extension direction of the flow path may be the vertical direction, that is, a direction in which the circulation device C and the heating device 100 are stacked. Based on the extension direction of the flow path, the burner 120 may be arranged to be biased rearward, that is, toward the rear panel 20, thereby preventing the burner 120 and the heating chamber S2 from overlapping with each other.

Based on the extension direction of the flow path in which the combustion chamber S5 and the heating chamber S2 are connected to each other, the entire part or a part or portion of the burner 120 may be arranged at a position at which the burner 120 overlaps with the discharge chamber S3. As illustrated in FIG. 11, a part or portion of the burner 120 may be arranged to overlap with the discharge chamber S3 vertically.

In this embodiment, the heating device 100 may protrude rearward, that is, toward the rear panel 20, more than the circulation device C. Referring to FIGS. 11 and 12, the heating device 100 may protrude to a position adjacent to a surface of the rear panel 20, but the circulation device C may be relatively spaced apart forwardly from the surface of the rear panel 20 (the left side based on the drawing). As described above, an extension part or portion (not given reference numeral) where the heating device 100 further protrudes than the circulation device C may be used as an inflow space to introduce external air into the heating device 100. Through an upper portion and a lower portion of the extension portion where the heating device 100 protrudes further than the circulation device C, external air may be efficiently introduced into the combustion chamber S5. As described hereinafter, a portion where the heating device 100 and the rear panel 20 face each other may be formed at a predetermined distance to form an introduction path, and external air may be introduced into the combustion chamber S5 through the introduction path.

Referring to FIGS. 13 to 17, the heating device 100 will be described. The heating device 100 may include the combustion chamber S5 therein, and the combustion chamber S5 may include the burner 120. The burner 120 may generate a flame using gas and heat air in the combustion chamber S5. The heating device 100 may heat air in the combustion chamber S5 and transfer the heated air to the heating chamber S2.

The combustion chamber S5 may form the lower flow path through which air heated by the burner 120 flows to the upper flow path. The upper flow path may be considered an air transfer path inside of the circulation chamber SA. In this embodiment, the upper flow path and the lower flow path may be connected to each other in a heightwise direction of the frame 60 through the connection passage 61a provided in the frame lower surface 61.

The burner case 110 may form a frame of the heating device 100. The burner case 110 may have a roughly hexahedral structure. The burner case 110 may be made of a metal material having high heat-resistance, for example. A part or portion of an upper surface and a rear surface of the burner case 110 may be open. The open portion of the upper surface of the burner case 110 may be covered by the frame lower surface 61. The open rear surface of the burner case 110 has the chamber opening 118, and the chamber opening 118 may be covered by the shielding cover 28 described above. This structure will be described hereinafter.

The burner case 110 may include a front plate 111 forming a front surface of the combustion chamber S5. The burner case 110 may include side plates 112 that form side surfaces of the combustion chamber S5. The burner case 110 may include an upper plate 113 that provides an upper surface of the combustion chamber S5. The burner case 110 may include lower plate 117 that forms a bottom surface of the combustion chamber S5. The front plate 111, the side plates 112, the upper plate 113, and the lower plate 117 may be formed by bending one metal sheet. As another example, the burner case 110 may be formed of multiple components that are coupled to each other using a method, such as welding or assembled with each other by a fastener, such as a screw.

The front plate 111 may include the spacer 111a. The spacer 111a may be formed of a part or portion of the front plate 111 that protrudes into the combustion chamber S5. The spacer 111a may form an uneven structure on a section of the front plate 111. In this embodiment, the multiple spacers 111a may be arranged in a longitudinal direction of the front plate 111, that is, at intervals in an extension direction of the burner 120.

The spacer 111a may be in close contact with a guide front surface 131 of the flow path guide 130 arranged in the combustion chamber S5. A gap between one spacer 111a and another spacer 111a adjacent thereto is spaced apart from the guide front surface 131 to form a passage. The passage may be cooling flow path CP1. When some of the external air introduced into the combustion chamber S5 which is not heated by the burner 120 or air at the bottom side of the combustion chamber S5 which is less affected by the burner 120 rises or flows upward through the cooling flow path CP1, the air may cool not only the front plate 111 and a surface of the flow path guide 130 but also the frame lower surface 61. The cooling flow path CP1 may be referred to as first cooling flow path CP1 to distinguish it from cooling flow path CP2, which is a different path described hereinafter.

The spacer 111a may extend to an upper end of the front plate 111 and may be provided only to the upper portion rather than a lower end of the front plate 111. Referring to a path indicated by arrow {circle around (7)} of FIG. 19, a continuous path may be formed from a portion where a front portion of the lower plate 117 and a lower portion of the front plate 111 without the spacer 111a are connected to each other, to the first cooling flow path CP1 provided between a surface of the guide front surface 131 and a rear surface of the front plate 111. External air may pass through the path. As another example, the spacer 111a may protrude from the guide front surface 131 toward the front plate 111, rather than the front plate 111.

As described above, a portion of the cooling flow path CP1, CP2 may be formed in a heightwise direction of the combustion chamber S5 between the surface of the burner case 110 and the surface of the flow path guide 130 facing each other.

Referring to FIG. 13, each side plate 112 may include a bracket hole 112a through which a bracket 129 of the burner 120 may pass. The bracket 129 passing through the bracket hole 112a may be fixed to the frame 60. For reference, in this embodiment, the burner 120 may remain fixed by the bracket 129 and a burner fixation piece 128 of the burner 120, which will be described hereinafter.

The upper plate 113 may include an interference avoidance part or portion 113a. The interference avoidance portion 113a may be formed such that a part or portion of the upper plate 113 is omitted to expose the combustion chamber S5. The interference avoidance portion 113a may be provided to prevent interference with structure (not illustrated) that protrudes from a lower portion of the frame 60.

To form the interference avoidance portion 113a, a part or portion of the upper plate 113 may be cut and then bent downward. The bent portion may be a fixation rib 113b. Referring to FIG. 21, the burner fixation piece 128 provided at the burner 120 may be coupled to the fixation rib 113b. Eventually, one end portion of the burner 120 may be supported by the fixation rib 113b.

The upper plate 113 may include an upper opening 116 at a portion adjacent to the interference avoidance portion 113a. The upper opening 116 may have a form in which a part or portion of the upper plate 113 is vertically open. The upper opening 116 may be formed in a long shape that extends lengthwise in the extension direction of the burner 120. The upper opening 116 may be formed of a portion of the upper plate 113 cut and then bent upward.

The upper opening 116 may be covered with the frame rear surface 65. Referring to FIG. 19, a portion bent forward from a lower end of the frame rear surface 65 may cover the upper opening 116. The portion bent forward from the lower end of the frame rear surface 65 may overlap with an upper portion of the frame lower surface 61. The end of the frame rear surface 65 may be bent downward to form a flow path entrance end 65a. A structure of the flow path entrance end 65a will be described hereinafter.

A part or portion of the upper plate 113 may be bent to form a case supporter 115. As the case supporter 115 is bent, a space formed thereby may be the upper opening 116. The case supporter 115 may fix the heating device 100 to the frame 60. As the case supporter 115 is coupled to the frame 60, the heating device 100 may be supported by the frame 60. Referring to FIGS. 10 and 18, the case supporter 115 in close contact with the frame rear surface 65 is illustrated. In this state, a fastener, such as a screw (not illustrated), may fix the case supporter 115 to the frame 60. Reference numeral B2 is a second coupling part or portion where the case supporter 115 is coupled to the frame rear surface 65. As described above, in this embodiment, the heating device 100 may be supported by being coupled to the frame 60.

More specifically, the heating device 100 may be coupled to a first surface among surfaces of the frame rear surface 65, the first surface facing the rear panel 20. On the other hand, the circulation device C may be fixed to a second surface among surfaces of the frame rear surface 65, the second surface facing the cooking chamber S1. As described above, the circulation device C may be fixed to a first surface among wall surfaces of the frame 60, the first surface facing the cooking chamber S1, to provide a first coupling part or portion B1. The heating device 100 may be fixed to a second surface of the frame 60 opposite to the first surface to provide the second coupling portion B2.

More specifically, as described above, in this embodiment, the circulation device C may also be fixed to the frame 60. The cover coupling end 83 provided at the end of the cover bent portion 82 may be coupled to the frame rear surface 65 while overlapping with the partition coupling end 73 of the partition plate 70. The lower end portion of the partition plate 70 and the lower end portion of the cover plate 80 may be supported by the frame 60. Referring to FIG. 18, a lower end bent portion 71a of the partition plate 70 may be in close contact with an upper portion of the frame rear surface 65 to provide the first coupling portion B1 (referring to FIG. 19). Further, a lower end bent portion 81a of the cover plate 80 may be in close contact with the frame lower surface 61 to provide the first coupling portion B1.

As described above, the heating device 100 and the circulation device C may be coupled to the frame 60 to be supported thereby. The circulation device C and the heating device 100 may be fixed to the surfaces of the frame 60 at different positions. The heating device 100 may be supported by the frame 60, so the heating device 100 may not depend on the circulation device C for mounting thereof. Accordingly, the heating device 100 may not be in direct contact with the circulation device C. In other words, while the surface of the circulation device C and the surface of the heating device 100 are in non-contact with each other, the heating device 100 may be fixed to the frame 60. Accordingly, an amount of radiant heat generated from the surface of the heating device 100 which is transferred to the circulation device C is reduced, and a flame of the burner 120 may be focused to heat air in the combustion chamber S5.

Referring to FIG. 14, the rear surface of the burner case 110 is open, and the chamber opening 118 may be formed thereby. The chamber opening 118 may be shaped in a roughly rectangle around edges of the upper plate 113, the lower plate 117, and the side plates 112. The chamber opening 118 may be open toward the rear panel 20. The chamber opening 118 may be connected to the panel opening 23 of the rear panel 20 but may be covered by the shielding cover 28.

Referring to FIG. 19, the lower plate 117 may include an uneven part or portion 117a. In this embodiment, the uneven portion 117a is arranged at a lower portion of the burner 120. The uneven portion 117a may be formed into a shape in which a part or portion of the lower plate 117 is bent. The uneven portion 117a increases a strength of the lower plate 117 to prevent the lower plate 117 from being deformed due to a high temperature of the combustion chamber S5.

The uneven portion 117a may expand a contact area between the burner case 110 and external air passing through the lower portion of the burner case 110. The external air passing through the burner case 110 performs heat exchange by being brought into contact with the uneven portion 117a, and in this process, the lower plate 117 and the burner case 110 may be cooled. The external air is naturally introduced into the combustion chamber S5 which is at a relatively low pressure, and the external air may pass through the lower plate 117 in this state.

An air inlet passage SP may be formed below the lower plate 117. The air inlet passage SP may be formed between the frame lower surface 61 and the drawer cover 47 or the frame lower surface 61 and the lower panel 17. The air inlet passage SP is a kind of space and may be considered a part or portion of the installation space IS. The air inlet passage SP may be a path through which external air is induced into the heating device 100.

In FIG. 19, arrow {circle around (4)} indicates a flow direction of external air that passes through the uneven portion 117a and cools the lower plate 117. The external air may pass through the air inlet passage SP and be brought into contact with the lower plate 117. As described above, the air cooling the lower plate 117 may move continuously along the air inlet passage SP, and may enter the combustion chamber S5 through the second inlet IP2, that is, a gap between the burner case 110 and the rear panel 20. This structure will be described hereinafter.

The frame lower surface 61 may include a combustion air hole 119. The combustion air hole 119 may be formed vertically through the frame lower surface 61. The combustion air hole 119 may be connected to a holder air hole 127a′ of the nozzle holder 127, which will be described hereinafter. Air introduced through the combustion air hole 119 may be supplied to the nozzle through the holder air hole 127a′ and may be used in a primary combustion of gas. Therefore, the combustion air hole 119 may constitute a first inlet.

Next, referring to FIG. 15, the burner 120 of the heating device 100 will be described. For reference, FIG. 15 illustrates the flame guide 140 described hereinafter coupled to the burner 120. As described above, the burner 120 may be a linear pipe that extends in one direction along a rear edge of the lower portion of the frame 60. A burner body 121 forming a frame of the burner 120 may be shaped as a bar that extends in one direction. The burner body 121 may extend along a longitudinal direction of the burner case 110. Inside of the burner body 121, a gas flow path 121a may extend in a frontward-rearward direction, and a mixed gas may be supplied thereinto.

The burner 120 may be arranged at a position deviating from a heating flow path GP. The heating flow path GP is a flow path of air generated by the flow path guide 130, which will be described hereinafter. The heating flow path GP may be considered a path that connects the combustion chamber S5 and the heating chamber S2 to each other. As described above, when the burner 120 is arranged at a position deviating from the heating flow path GP, a distance from the burner 120 to the heating flow path GP may be secured, and a space in which air heated by a flame exists may be sufficiently formed. The burner 120 may generate a flame toward the heating flow path GP.

Referring to FIG. 6, a spark plug 122 is connected to the burner 120. The spark plug 122 may enable the mixed gas to be burned. The spark plug 122 may include a connector 122a (referring to FIG. 13) configured to be connected to a power source. The connector 122a may be coupled to a power component inside of the outer case 10.

A mixing tube 123 may be provided at one side portion of the burner body 121. The mixing tube 123 may mix external air and gas from the nozzle holder 127. When the burner 120 is operated, gas is supplied from the nozzle holder 127 to one end portion of the burner 120. A structure in which a width of the mixing tube 123 is reduced causes a lower pressure, and a pressure difference enables surrounding air to be naturally supplied toward the mixing tube 123. In addition, when the mixed gas is burned by the spark plug 122, a flame may be generated from a flame hole 125.

Referring to FIG. 21, a tube air hole 124 may be open in a lower portion of the mixing tube 123. The tube air hole 124 may be open toward the lower plate 117. The tube air hole 124 may be connected to the holder air hole 127a′ of the nozzle holder 127 coupled to the mixing tube 123. Accordingly, external air may pass through the holder air hole 127a′ and the tube air hole 124 and then may be introduced into the gas flow path 121a of the burner body 121. For reference, the lower plate 117 may include the combustion air hole 119 open in a position facing the tube air hole 124. Through the combustion air hole 119, external air, more specifically, external air introduced into the installation space IS may be introduced. The combustion air hole 119 may form the first inlet IP1, which will be described hereinafter.

More specifically, when gas is supplied into the burner body 121, some of air required for combustion (hereinafter, referred to as “primary air”) is introduced with the gas, and mixed gas in which the gas and the air are mixed may be burned at the flame hole 125. In addition, at a periphery of the flame where combustion is performed, air is newly introduced toward the flame (hereinafter, referred to as “secondary air”), which causes complete combustion. As described above, only when the secondary air is supplied in a sufficient quantity in the combustion process, may complete combustion be achieved. Accordingly, an efficiency of the burner 120 may increase. A supply structure of the secondary air will be described hereinafter.

Referring to FIG. 15, the flame hole 125 may be formed through the burner body 121. The flame hole 125 forms a passage through which mixed air inside of the burner body 121 is discharged outside of the burner body 121. Multiple flame holes 125 may be arranged at a side portion of the burner body 121 at predetermined intervals along a longitudinal direction of the burner body 121. Accordingly, the burner body 121 may include multiple gas discharge passages along the longitudinal direction of the burner body 121. Reference numeral 126 is an auxiliary flame hole arranged in front of the flame hole 125 to transfer flame.

In this embodiment, the flame hole 125 is provided only in a front surface of the burner body 121. The front surface of the burner body 121 is a surface of the burner 120 facing the door 50. The flame hole 125 is not provided in an upper, lower, or rear surface of the burner 120, and is provided only in a surface facing forward. The flame hole 125 may face the flow path guide 130.

The flame hole 125 may be open toward the lower flow path. The lower flow path is a path through which air flows inside of the combustion chamber S5. In this embodiment, at least a part or portion of the lower flow path may be formed by the flow path guide 130. When the flame hole 125 faces the lower flow path, a flame generated from the flame hole 125 does not heat a surface of the burner case 110 but heats concentrically air in the combustion chamber S5. Therefore, the burner 120 may heat air in the combustion chamber S5 efficiently, and it is possible to prevent the burner case 110 from being overheated by radiant heat. Further, in other words, an open direction of the flame hole 125 of the burner 120 may be in parallel to the direction of the rotational shaft 92 of the circulation fan 93. Otherwise, the flame hole 125 of the burner 120 may be open toward a flow path through which the circulation chamber SA and the combustion chamber S5 are connected to each other.

The multiple flame hole 125 may produce multiple flames. The multiple flame holes 125 may be arranged in the longitudinal direction of the burner body 121. Further, the multiple flame holes 125 may be arranged along a circumferential direction of the burner body 121. In this embodiment, the burner 120 includes three flame hole arrays having different angles along the circumferential direction. The three flame hole arrays may provide stronger firepower as flames from the three flame hole arrays are combined together.

The nozzle holder 127 may be provided at one side of the burner body 121. The nozzle holder 127 may transfer externally-supplied gas to the burner body 121. The nozzle holder 127 may be connected to a nozzle (not illustrated) of an external gas pipe (not illustrated). The nozzle holder 127 may transfer gas supplied from the gas pipe to the gas flow path 121a, and air and gas may be mixed in this process.

Referring to FIG. 21, a holder main body 127a of the nozzle holder 127 may be coupled to one end portion of the burner body 121 by covering the end portion. The holder air hole 127a′ may be formed in a lower portion of the holder main body 127a. The holder air hole 127a′ may be connected to the tube air hole 124 provided in the mixing tube 123. The holder air hole 127a′ may be connected to the tube air hole 124 to form one air suction passage. The air suction passage may be a path through which the primary air is supplied.

Referring to FIG. 21, the path through which the primary air at the external space is introduced is illustrated. The primary air may be introduced through the combustion air hole 119, that is, the first inlet IP1 formed in the lower plate 117, toward the inside space of the combustion chamber S5 (direction of arrow {circle around (1)}). In addition, the introduced primary air may pass through the holder air hole 127a′ and the tube air hole 124 successively, and then move along the gas flow path 121a of the burner body 121 (direction of arrow {circle around (3)}). The primary air may be introduced not only through the combustion air hole 119 but also through the panel opening 23 of the rear panel 20 (direction of arrow {circle around (2)}). The panel opening 23 is open toward the nozzle holder 127 so that the primary air may be efficiently supplied.

The combustion air hole 119 and the panel opening 23 may form the first inlet IP1. The first inlet IP1 may be a passage through which air is directly supplied to the gas flow path 121a of the burner body 121. Even when the panel opening 23 is shielded by the shielding cover 28, the nozzle holder 127 is open, so it may be a part or portion of the first inlet. As another example, one of the combustion air hole 119 or the panel opening 23 may be omitted, and only the remaining one may form the first inlet IP1.

A gas inlet hole 127b may be open in the nozzle holder 127. The gas inlet hole 127b may be connected to the gas pipe. In this embodiment, the gas inlet hole 127b may be open in a different direction from the holder air hole 127a′. More specifically, the gas inlet hole 127b may face the panel opening 23 of the rear panel 20. Accordingly, the gas inlet hole 127b may be exposed outward through the panel opening 23. In FIG. 21, arrow {circle around (4)} indicates a path through which external gas is supplied toward the gas inlet hole 127b.

Referring to FIG. 21, the burner fixation piece 128 coupled to the burner main body 121 may be in close contact with the fixation rib 113b. The burner body 121 may be fixed to the burner case 110 and the frame 60 by the burner fixation piece 128 and the bracket 129 at the opposite side.

The flow path guide 130 forming the heating device 100 will be described hereinafter. Referring to the exploded view of FIG. 7, the flow path guide 130 may be shaped in a roughly hexahedron shape. The flow path guide 130 may be stored in the combustion chamber S5, so that the flow path guide 130 may have a volume less than or equal to a volume of the combustion chamber S5. The flow path guide 130 may be formed as a separate component from the burner case 110 and then arranged at the combustion chamber S5. As another example, the flow path guide 130 may be integrated with the burner case 110.

The flow path guide 130 may form multiple flow paths with the burner case 110. The flow path guide 130 may partition the combustion chamber S5 into multiple spaces and generate respective air flows in the partitioned spaces. The term “partitioned” means that, even when two spaces are not completely separated from each other, air flows into each separate space. As described hereinafter, the flow path guide 130 may partition a connection passage 61a′ into a heating outlet 134 and a cooling outlet OP1, OP2.

The flow path guide 130 may partition the combustion chamber S5 into multiple flow paths. A part or portion GP of the flow paths may transfer high temperature air heated by the burner 120 to the circulation chamber SA, and the other part or portion CP1, CP2 may cool components while allowing relatively low temperature air to pass therethrough. The flow path through which high temperature air passes may be the heating flow path GP, and the flow path through which low temperature air passes may be the cooling flow path CP1, CP2. In other words, the heating flow path GP may be a guide flow path that guides heated high temperature air along the inside space of the flow path guide 130. The cooling flow path CP1, CP2 provided outside of the flow path guide 130 may be a cooling flow path through which relatively low temperature air introduced from the external space flows. The above-mentioned flow paths will be described hereinafter.

As described above, the flow path guide 130 may provide the heating flow path GP and the cooling flow path CP1, CP2 separated from each other, inside of the combustion chamber S5. The heating flow path GP may be a path through which air heated by the burner 120 flows. The cooling flow path CP1, CP2 may be a path arranged around the burner 120, and may be a path through which relatively lower temperature air than the air flowing through the heating flow path GP flows.

The cooling flow path CP1, CP2 may include first cooling flow path CP1 and second cooling flow path CP2. The first cooling flow path CP1 may be a path that passes through an upper portion of the burner 120. The second cooling flow path CP2 may be a path that passes through a lower portion of the burner 120 and connected with the circulation device C along a surface of the heating device 100. This structure will be described hereinafter.

High temperature air of the combustion chamber S5 heated by the burner 120 may be transferred to the circulation chamber SA. More specifically, the flow path guide 130 may be connected to the heating chamber S2 in the circulation chamber SA and transfer heated air to the heating chamber S2. The flow path guide 130 may form a lower flow path inside of the combustion chamber S5. The lower flow path may be connected to an upper flow path formed by the heating chamber S2. The lower flow path may be considered the heating flow path GP provided inside of the flow path guide 130.

The flow path guide 130 may be open upward and rearward. An upward direction means a direction toward the heating chamber S2. A rearward direction means a direction toward the burner 120. The flow path guide 130 may guide a flow of air between the burner 120 and the heating chamber S2 through the heating flow path GP open upward and downward.

Referring to FIGS. 13 and 14, the flow path guide 130 may be inserted through the upper opening 116 of the burner case 110. The burner case 110 may be arranged in the upper opening 116 and may form a flow path of air moving upward through the upper opening 116. The flow path guide 130 may be shaped in a roughly hexahedron shape. The flow path guide 130 may be coupled to the burner case 110.

More specifically, the flow path guide 130 may include the guide front surface 131, a guide side 132, a guide upper surface 133, and a guide rear surface 135. The guide front surface 131 may form a front surface of the flow path guide 130. The guide side 132 may form a side surface of the flow path guide 130. The guide upper surface 133 may form an upper surface of the flow path guide 130. The guide rear surface 135 may form a rear surface of the flow path guide 130.

The heating outlet 134 may be open in the guide upper surface 133. The heating outlet 134 may be formed vertically in the guide upper surface 133. The heating outlet 134 may connect the heating flow path GP formed in the flow path guide 130 to the heating chamber S2. Multiple heating outlets 134 may be arranged in a leftward-rightward direction of the flow path guide 130. As another example, the heating outlet 134 may be shaped into one continuous long hole.

The guide front surface 131 may be in close contact with the front plate 111 of the burner case 110. More specifically, the guide front surface 131 may be in close contact with the spacer 111a of the front plate 111. The guide front surface 131 may be coupled to the spacer 111a by a fastener, such as a screw (not illustrated), or welded thereto. In this embodiment, the flow path guide 130 may be coupled only to the spacer 111a, and a remaining part or portion thereof may be not coupled to the burner case 110.

Referring to FIGS. 18 to 20, a width of an upper end of the flow path guide 130 may be narrower than a width of the connection passage 61a. Accordingly, an outer surface of the flow path guide 130 and an inner surface of the connection passage 61a may be spaced apart from each other. The cooling outlet OP1, OP2 may be formed between the flow path guide 130 and the connection passage 61a, which are spaced apart from each other as described above. The cooling outlet OP1, OP2 may be formed without disconnection around a surface of the upper end of the flow path guide 130. As another example, the cooling outlet OP1, OP2 may be partitioned into outlet OP1 of the flow path CP1 formed between the guide front surface 131 of the flow path guide 130 and the connection passage 61a, and outlet OP2 of the flow path CP2 formed between the guide rear surface 135 and the connection passage 61a, and the two outlets may not be connected to each other.

The cooling flow path CP1, CP2 may be provided around the flow path guide 130. At least a part or portion of the cooling flow path CP1, CP2 may be formed along a space that surrounds the flow path guide 130. Then, the first cooling flow path CP1 and the second cooling flow path CP2 may serve an insulation function around the heating flow path GP. The cooling flow path CP1, CP2 may be provided at the outside space of the flow path guide 130 and the inside space of the burner case 110.

As described above, the flow path formed by the flow path guide 130 may be partitioned. In other words, (i) the heating flow path GP formed inside of the flow path guide 130 and transferring heated air to the heating chamber S2 and (ii) the cooling flow path CP1, CP2 formed around the heating flow path GP and through which air having relatively low temperature passes are partitioned from each other. In other words, the heating flow path GP and the cooling flow path CP1, CP2 may form two flow paths.

The cooling flow path CP1, CP2 may include the first cooling flow path CP1 and the second cooling flow path CP2. The first cooling flow path CP1 and the second cooling flow path CP2 may be provided at respective outside portions of the flow path guide 130. The first cooling flow path CP1 and the second cooling flow path CP2 may be arranged at opposite sides with the heating flow path GP located therebetween, and may form different air flow paths. The first cooling flow path CP1 and the second cooling flow path CP2 are the same with respect to (i) connection between the combustion chamber S5 and the heating chamber S2, and (ii) pass of relatively low temperature air by formation of each path partitioned from the heating flow path GP.

The first cooling flow path CP1 may surround an upper end portion of the flow path guide 130 with the second cooling flow path CP2. Accordingly, the heating flow path GP provided inside of the flow path guide 130 may be a path through which air heated at a high temperature flows, and the second cooling flow path CP2 surrounding the heating flow path GP may be a cooling path through relatively low temperature air passes. The cooling path surrounds the heating flow path GP, thereby forming a kind of insulation layer.

Referring to FIG. 18, the upper end portion of the flow path guide 130 protruding into the heating chamber S2 is illustrated. In this embodiment, a part or portion of the flow path guide 130 passes through the connection passage 61a and then extends into the heating chamber S2. The heating outlet 134 of the heating flow path GP may also be located inside of the heating chamber S2. Accordingly, heated air passing through the heating flow path GP is prevented from leaking out of the flow path guide 130 and may be precisely transferred into the heating chamber S2. As described above, a part or portion of the flow path guide 130 protruding into the heating chamber S2 may be a protrusion (reference numeral not given).

When the protrusion which is a part of the flow path guide 130 passes through the connection passage 61a and then enters the inside space of the heating chamber S2, the heating outlet 134, which is the outlet of the heating flow path GP and the cooling outlet OP1, OP2 which is the outlet of the cooling flow path CP1, CP2 have a height difference therebetween. More specifically, the heating outlet 134 may be formed higher than the cooling outlet OP1, OP2. This structure may prevent high temperature air that is discharged through the heating outlet 134, and relatively low temperature air that is discharged through the cooling outlet OP1, OP2 from being mixed in the connection passage 61a. Therefore, high temperature air passing through the heating flow path GP may efficiently heat air inside of the heating chamber S2, and low temperature air passing through the cooling flow path CP1, CP2 may cool components around the connection passage 61a. More specifically, the lower portion of the frame 60 forming the surrounding portion of the connection passage 61a may be prevented from being deformed due to high temperature heat, or the enamel coating layer of the frame 60 may be prevented from being damaged.

Referring to FIG. 13, when the guide front surface 131 is in close contact with the spacer 111a, a vertically extending space may be formed between the front plate 111, the spacers 111a, and a surface of the guide front surface 131. This space may form the first cooling flow path CP1. When external air is not heated by the burner 120 or air at a bottom side of the combustion chamber S5 which is less affected by the burner 120 is raised through the first cooling flow path CP1, the first cooling flow path CP1 may cool not only the front plate 111 and a surface of the guide front surface 131 but also the frame lower surface 61. For reference, a path formed along the lower plate 117, the lower portion of the burner 120, may also be considered a part or portion of the first cooling flow path CP1.

Referring to the plan view of FIG. 16, the first cooling flow path CP1 formed between the two spacers 111a is illustrated. The first cooling flow path CP1 may provide a continuous path between the spacers 111a. A lower end of the first cooling flow path CP1 may be open toward the lower plate 117 of the burner case 110.

Referring to FIG. 18, an upper end of the first cooling flow path CP1 may be open toward the combustion chamber S5 between an upper portion of the flow path guide 130 and the connection passage 61a formed through the frame lower surface 61. More specifically, with the upper end portion of the flow path guide 130 arranged in the connection passage 61a, the first cooling outlet OP1 is formed between an outer surface of the flow path guide 130 and an inner surface of the connection passage 61a. In other words, the first cooling outlet OP1 may be formed around the upper end portion of the flow path guide 130.

Referring to FIG. 19, the second cooling flow path CP2 formed by the flow path guide 130 is illustrated. The second cooling flow path CP2 may be provided at the upper portion of the burner 120. The second cooling flow path CP2 may be formed between the flow path guide 130 and the frame lower surface 61. As described above, the second cooling flow path CP2 may be provided along an upper portion of the combustion chamber S5.

The second cooling flow path CP2 may be a flow path through which, in external air introduced into the combustion chamber S5, some of the air moving along the upper surface of the burner 120 passes. The air passing through the second cooling flow path CP2 may cool a surface of the flow path guide 130 and the frame lower surface 61. In FIG. 19, arrow 9 indicates a flow path of air moving along the second cooling flow path CP2. As described hereinafter, the second cooling outlet OP2, that is, an outlet of the second cooling flow path CP2, may be formed between the guide rear surface 135 and the flow path entrance end 65a of the frame lower surface 61.

In this embodiment, the second cooling flow path CP2 may extend parallel to the upper surface of the combustion chamber S5, that is, the upper plate 113 or the frame lower surface 61. Otherwise, the first cooling flow path CP1 may be formed parallel to a surface of the combustion chamber S5, that is, the front plate 111. As described above, the first cooling flow path CP1 and the second cooling flow path CP2 may extend in respectively different directions, or in respective areas. In this embodiment, a start path of the first cooling flow path CP1 is provided lower than the flame hole 125, and a start path of the second cooling flow path CP2 is provided higher than the flame hole 125.

The first cooling outlet OP1 and the second cooling outlet OP2, that is, the outlets of the cooling flow paths CP1 and CP2 may be formed between upper edges of the flow path guide 130 and the connection passage 61a provided in the frame lower surface 61. The first cooling outlet OP1 and the second cooling outlet OP2 may include structure that covers the heating outlet 134 of the heating flow path GP. Then, the first cooling outlet OP1 and the second cooling outlet OP2 may serve an insulation function around the heating outlet 134 of the heating flow path GP. For reference, each of the first cooling outlet OP1, the second cooling outlet OP2, and the heating outlet 134 of the heating flow path GP may serve as an inlet based on the circulation device C.

The first cooling flow path CP1 and the second cooling flow path CP2 may be partitioned from the heating flow path GP, and the first cooling flow path CP1 and the second cooling flow path CP2 may be connected to each other at the cooling outlets OP1 and OP2. The first cooling outlet OP1 may be formed between the guide front surface 131 and the connection passage 61a, and the second cooling outlet OP2 may be formed between the guide rear surface 135 and the connection passage 61a. The first cooling outlet OP1 and the second cooling outlet OP2 may be connected to each other between the guide side 132 forming the cooling outlet OP1, OP2 and the connection passage 61a. Accordingly, the first cooling outlet OP1 and the second cooling outlet OP2 may be connected to each other to be shaped in a roughly rectangle shape.

The first cooling outlet OP1 and the second cooling outlet OP2 may be connected to each other to form a continuous path. The flow path guide 130 and the connection passage 61a have rectangular forms, respectively. Therefore, the continuous cooling outlet OP1, OP2 formed by the first cooling outlet OP1 and the second cooling outlet OP2 may entirely have a rectangular channel structure. In other words, based on a plan structure, the heating outlet 134 having a rectangular form may be covered by the cooling outlet OP1, OP2 having a larger rectangular form.

The guide rear surface 135 may be formed with a vertical length shorter than the guide front surface 131. Accordingly, the guide rear surface 135 may be spaced apart from the lower plate 117 in an upward direction by a longer distance than the guide front surface 131. In other words, a lower end of the guide rear surface 135 is spaced upward apart from the bottom of the combustion chamber S5 more than a lower end of the guide front surface 131, so an entrance of the heating flow path GP may be open toward the burner 120. Through the entrance of the heating flow path GP, a flame F of the burner 120 may be guided into the heating flow path GP. Therefore, the entrance of the heating flow path GP may be formed between the lower end of the guide rear surface 135 and the lower plate 117.

A part or portion of the guide rear surface 135 may be bent, and a rear bent portion 135a may be provided. The rear bent portion 135a may extend toward the rear panel 20, more specifically, in parallel to an open direction of the flame hole 125. Referring to FIG. 19, the rear bent portion 135a may reduce a distance between a guide end portion 145a of the flame guide 140, which will be described hereinafter, and the flow path guide 130. A first gap G1 may be formed between the rear bent portion 135a and the guide end portion 145a as the rear bent portion 135a and the guide end portion 145a are spaced apart from each other by a predetermined distance. The secondary air may be introduced through the first gap G1 described above. In other words, the first gap G1 may be connected to the entrance of the heating flow path GP. When some of the air introduced from the external space is introduced through the first gap G1 between the rear bent portion 135a and the guide end portion 145a, the air may be the secondary air supplied to the burner 120. This secondary air may be supplied as a flame F generated through the flame hole 125 of the burner 120 to help complete combustion.

The flow path guide 130 may include a guide fence 137. The guide fence 137 may be provided at a lower end of the guide front surface 131. The guide fence 137 may protrude in a direction inclined to the burner 120 with respect to the vertical direction. The guide fence 137 may guide air heated by the burner 120 toward the heating flow path GP. The guide fence 137 may enable air heated by the flame F of the burner 120 not to move to the first cooling flow path CP1 and to move along the heating flow path GP to the heating chamber S2.

Referring to FIG. 18, a lower end of the guide fence 137 may be provided at a position lower than the flame hole 125. Reference numeral H1 may indicate an imaginary horizontal line that passes through a lowest flame hole 125 among the multiple flame holes 125 of the burner 120. It may be shown that each flame hole 125 of the burner 120 is located higher than the lower end of the guide fence 137. Accordingly, when the flame F generated from each flame hole 125 heats air, the heated air may be guided higher than the lower end of the guide fence 137. Further, when the flame F extends lengthwise in the frontward-rearward direction, the guide fence 137 may prevent the flame F from facing the first cooling flow path CP1.

Next, the flame guide 140 will be described. The flame guide 140 may guide the flame a direction in which the flame of the burner 120 is generated. The flame guide 140 may guide a flow of air so that the air heated by the burner 120 moves to the heating flow path GP. The flame guide 140 may be arranged between the burner 120 and the flow path guide 130. Accordingly, the flame F of the burner 120 and the heated air may be guided toward the flow path guide 130 along the flame guide 140.

In this embodiment, the flame guide 140 may be arranged between an upper portion of the flame holes 125 and the heating flow path GP of the flow path guide 130. The flame F generated from each flame hole 125 is blocked by the flame guide 140, and does not extend upward anymore, thereby facing the heating flow path GP along the flame guide 140. Therefore, the burner 120 may concentrically heat air moving upward through the heating flow path GP.

The flame guide 140 may be made of a material having high heat resistance. The flame guide 140 may be made of a flat material. The flame guide 140 may extend lengthwise in the longitudinal direction of the burner 120. The flame guide 140 may have a length that may completely cover an area where the flame holes 125 are arranged.

In this embodiment, the flame guide 140 may include a fixation body 141 and a guide blade 145. The fixation body 141 and the guide blade 145 may be a connected flat structure. The fixation body 141 may be coupled to the burner 120. The fixation body 141 may be coupled to a surface of the burner 120. The fixation body 141 may be shaped in a curved surface corresponding to the surface of the burner 120. Referring to FIG. 13, the fixation body 141 may be coupled to a guide coupling part or portion 121b provided on the surface of the burner 120. As described above, a part or portion of the flame guide 140, that is, the fixation body 141 is coupled to the burner 120, and the guide blade 145 may extend from the fixation body 141 toward the flow path guide 130. More specifically, the guide end portion 145a provided at an end of the guide blade 145 may extend in a direction inclined upward to the connection passage 61a.

Referring to FIG. 19, the flame F may extend at a lower portion of the guide blade 145. A part or portion of the heating flow path GP guiding heated air may be formed between a lower portion of the flame guide 140 and a bottom surface of the burner case 110. The lower portion of the guide blade 145 and the lower plate 117 are spaced apart from each other to provide a space, and the space may form a part or portion of the heating flow path GP. The lower portion of the guide blade 145 may be considered a flame space where the flame F is generated.

Air introduced from the external space may move to an upper portion of the guide blade 145. An external air space S6 may be provided between the upper portion of the guide blade 145 and the upper plate 113 and the secondary air introduced from the external space may be introduced into the external air space S6. The external air space S6 may form the second cooling flow path CP2. The air passing through the external air space S6 may cool the surrounding portion and may be transferred to the lower portion of the frame 60 through the cooling outlet OP2.

A part or portion of the secondary air passing through the external air space S6 enters the heating flow path GP through the first gap G1 between the guide end portion 145a and the rear bent portion 135a to help complete combustion of the burner 120. As described above, a part or portion of the secondary air entering the external air space S6 may move to the first gap G1 between the guide end portion 145a and the rear bent portion 135a to join the heating flow path GP.

More specifically, the external air space S6 may be formed between the flame guide 140 and the frame rear surface 65 covering the upper opening 116 of the burner case 110. External air introduced into the external air space S6, based on the rear bent portion 135a, (i) may enter the second cooling outlet OP2, which is an outlet of the second cooling flow path CP2, through a second gap G2 formed at an upper portion of the rear bent portion 135a (direction of arrow {circle around (9)}), and (ii) may join with the entrance of the heating flow path GP through the first gap G1 formed between the rear bent portion 135a and the guide end portion 145a. The air joining the heating flow path GP may be transferred to the flame generated from the burner 120 to be the secondary air helping complete combustion.

With the above configuration, the external air space S6 may form a part or portion of the second cooling flow path CP2. Air passing through the second cooling flow path CP2 may be transferred to the lower portion of the frame 60 through the second cooling outlet OP2 to perform the cooling function.

An end of the rear bent portion 135a may protrude toward the rear panel 20 more than the guide end portion 145a, thereby guiding the secondary air toward the entrance of the heating flow path GP. The rear bent portion 135a may be arranged between the guide end portion 145a and the flow path entrance end 65a. Based on the rear bent portion 135a, a junction part or portion (the first gap part G1) of the heating flow path GP formed between the rear bent portion 135a and the guide end portion 145a and the flow path entrance end 65a, and a connection part or portion G2 of the second cooling outlet OP2 formed between the rear bent portion 135a and the flow path entrance end 65a may be partitioned. With the above configuration, the second gap G2, that is, the connection part or portion G2 between the rear bent portion 135a and the flow path entrance end 65a may be connected to the second cooling outlet OP2. In this embodiment, the second gap G2 may be positioned higher than the burner 120.

As another example, the flame guide 140 and the burner case 110 are spaced apart from each other to form the joint portion (the first gap G1). When the flow path guide 130 is omitted, and the guide end portion 145a of the flame guide 140 extends to a position adjacent to the connection passage 61a, the junction portion (the first gap G1) may be formed between the guide end portion 145a and the connection passage 61a. As another example, the flow path guide 130 is integrated with the burner case 110, and the junction portion (the first gap G1) may be formed between the guide end portion 145a and one end portion of the flow path guide 130.

An upward inclined structure of the guide blade 145 may form the external air space S6 into a space with a width gradually reduced toward the guide end portion 145a. Accordingly, a velocity of air may increase as the air goes to the guide end portion 145a. The air with increased velocity may be efficiently transferred to the second cooling flow path CP2 or the first gap G1.

The external air space S6 may be a kind of insulation space S4 formed between the burner 120 and the frame 60. The external air space S6 may reduce an amount of radiant heat of the burner 120 transferred to the lower portion of the frame 60, more specifically, to a part or portion where the frame lower surface 61 and the frame rear surface 65 are connected to each other. This may increase a durability of the frame 60.

External air passing through the external air space S6 may cool the flame guide 140 while passing through the flame guide 140. Heat exchange is performed when the external air space S6 is in surface-contact with the surface of the flame guide 140, so the temperature of the flame guide 140 may be reduced, and overheating of the flame guide 140 may be prevented. In FIG. 19, arrow 8 indicates a flow direction of air moving along the surface of the burner 120. The air moved as described above may cool the flame guide 140 while passing through the flame guide 140. In addition, air moving continuously along the path that is the external air space S6 and the second cooling flow path CP2 may join the second cooling outlet OP2 of the second cooling flow path CP2, or may join the heating flow path GP through the first gap G1.

The air joining the heating flow path GP through the first gap G1 may be turned into a primarily heated state by heat exchange in the process in which the air cools the flame guide 140 while passing through the flame guide 140. Therefore, heat loss caused by the secondary air supplied from the external space may be minimized.

An end of the guide blade 145, that is, the guide end portion 145a may extend only to a range where the guide blade 145 does not intrude into the heating flow path GP. Referring to FIG. 18, the guide end portion 145a extending from the guide rear surface 135 to a position set back toward the burner 120 is illustrated. Based on an imaginary line that extends in the vertical direction in which the guide rear surface 135 is provided, the guide end portion 145a is arranged in an area that does not cross the imaginary line. Then, it is possible to prevent the guide end portion 145a from intruding into the heating flow path GP and interrupting a flow of air passing through the heating flow path GP.

Next, a process in which external air is heated by the heating device 100 and then supplied to the circulation device C will be described with reference to FIG. 19. First, after mixed gas in which air and gas are mixed is supplied to the burner 120, the spark plug 122 ignites, and then a flame is generated from each flame hole 125 of the burner 120. Arrow {circle around (1)} indicates a flow direction of the mixed gas, and arrow {circle around (2)} indicates a direction in which a flame is generated through each flame hole 125.

External air introduced for combustion of the mixed gas in the burner 120 may be divided into primary air and secondary air. The primary air may be introduced into the combustion chamber S5 through the first inlet (23, 119, referring to FIG. 21). At the same time, when gas supplied from the external space is sprayed through a nozzle, the gas sprayed through the nozzle and the primary air may be introduced together into the mixing tube 123. As described above, the gas and the air introduced into the mixing tube 123 may be mixed when flowing inside of the mixing tube 123 toward the burner body 121 to generate the mixed gas.

The secondary air is required to perform complete combustion of the mixed gas, and the secondary air may be supplied in a path different from the primary air. In the enlarged view of FIG. 11, the second inlet IP2 may be provided between the heating device 100 and the rear panel 20. The second inlet IP2 may be a predetermined space formed by the heating device 100 and the rear panel 20 being separated from each other.

More specifically, with reference to FIGS. 19 and 20, the second inlet IP2 may be formed in a gap between the burner case 110 and the surface of the rear panel 20. The second inlet IP2 may be provided between a rear end of the lower plate 117 forming the burner case 110 and the rear panel 20. Accordingly, the second inlet IP2 may be provided closer to the outer case 10, that is, the rear panel 20 than the connection passage 61a.

The second inlet IP2 may be provided along the surface of the outer case 10. External air may move along the surface of the outer case 10, and naturally be guided to the second inlet IP2. In this embodiment, the second inlet IP2 may be provided along the surface of the rear panel 20 of the outer case 10. More specifically, the second inlet IP2 may be provided in parallel to the surface of the rear panel 20.

Referring to FIG. 20, the rear end of the lower plate 117 facing the surface of the rear panel 20 is spaced apart from the rear panel 20, and the second inlet IP2 is formed therebetween. In this embodiment, the panel opening 23 is open in the rear panel 20, and the panel opening 23 may be covered with the shielding cover 28. Accordingly, the second inlet IP2 may be formed between the lower plate 117 and the shielding cover 28.

The second inlet IP2 may be provided between a rear end of the upper plate 113 and the rear panel 20. The rear end of the upper plate 113 may also be spaced apart from the surface of the rear panel 20, and a gap may be formed therebetween, and the gap may be the second inlet IP2. Accordingly, external air serving as the secondary air may be simultaneously introduced through two second inlets IP2 with different heights from each other.

When an insulator is filled in the insulation space S4, an upper portion of the upper plate 113 is filled with the insulator to reduce the path into which air may be introduced. In this case, the lower portion of the insulation space S4 is provided without the insulator to serve as a predetermined space for the second inlet IP2.

In this embodiment, the second inlet IP2 may be formed in a mounting direction of the burner 120, that is, the longitudinal direction of the burner 120. External air introduced through the second inlet IP2 is used as the secondary air for combustion of the burner 120, so it is necessary to supply the external air evenly to all the flame holes 125 of the burner 120. The second inlet IP2 may extend in the longitudinal direction of the burner 120. The second inlet IP2 may be provided in a leftward-rightward direction (Y-axial direction in FIG. 1) like the burner 120.

The chamber opening 118 may be formed in the burner case 110, and the second inlet IP2 may be connected to the chamber opening 118. The chamber opening 118 is a portion open rearward of the burner case 110, so the second inlet IP2 may be connected to the chamber opening 118. Accordingly, external air introduced into the second inlet IP2 may flow toward the burner 120 through the chamber opening 118. Of course, as illustrated in FIG. 22, the chamber opening 118 is covered with the rear panel 20 or the shielding cover 28, and therefore, the introduced air does not flow out rearward and may face the burner 120.

Referring to FIG. 23, the second inlet IP2 is illustrated enlarged. As illustrated in the drawing, the second inlet IP2 may be formed in a gap between the lower plate 117 and the shielding cover 28. As described above, the second inlet IP2 may be provided behind the burner case 110 closer to the rear panel 20 than the front plate 111 of the burner case 110. The external air may cool the lower plate 117 and the uneven portion 117a through the air inlet passage SP and then enter the second inlet IP2.

More specifically, external air flowing in the installation space IS may be introduced, at an end point of the air inlet passage SP that is blocked by the outer case 10, into the heating device 100 through the second inlet IP2. In this embodiment, the end point may be formed at a portion that is blocked by the rear panel 20 of the outer case 10. Accordingly, external air is introduced into the second inlet IP2 after passing through the surface of the heating device 100 along the air inlet passage SP, so the cooling function by the external air may be efficiently performed.

The second inlet IP2 may extend to a length equal to or longer than the length of the burner 120. Then, the second inlet IP2 may provide the secondary air evenly on a wide area of the burner 120.

The second inlet IP2 may be provided closer to the outer case 10 than the connection passage 61a. Then, air introduced into the second inlet IP2 may sufficiently pass through the combustion space S5 and the second heating flow path CP2 and then enter the second cooling outlet OP2. In this embodiment, the second inlet IP2 may be provided closer to the rear panel 20 than the connection passage 61a.

As described above, when the secondary air is introduced through the second inlet IP2, the burner 120 may completely burn the mixed gas. In this embodiment, the heating device 100 is spaced apart from the circulation fan 93 and arranged in an independent space. Therefore, the heating device 100 is not directly supplied with the secondary air from the circulation fan 93 and may be supplied with the secondary air through the above-described secondary air supply structure. In other words, the heating device 100 may suction external air as the secondary air without additional components, such as a motor, or a fan, for example. As another example, a separate flow path and a fan to induce the secondary air may be arranged in the heating device 100.

More specifically, in this embodiment, when air heated in the combustion chamber S5 moves to the heating chamber S2 through natural draft or rotation of the circulation fan 93, the pressure of the combustion chamber S5 is lowered. When the pressure of the combustion chamber S5 is lowered below that of the external space, that is, the pressure of the installation space IS, external air existing in the installation space IS may be naturally introduced into the combustion chamber S5 through the second inlet IP2. As described above, when the external air is introduced into the combustion chamber S5 by the negative pressure of the combustion chamber S5, a part or portion of the external air may be used as the secondary air, and a remaining part or portion of the external air may be used to cool components, such as the lower portion of the frame 60.

Referring to FIG. 19, a view illustrates a flow in which the air supplied from the external space is used as the secondary air. Air passing through the air inlet passage SP (direction of arrow {circle around (4)}) and cooling the lower plate 117 and the uneven portion 117a may be introduced to the combustion chamber S5 through the second inlet IP2 (direction of arrow {circle around (5)}).

As described above, a part or portion of the external air introduced into the combustion chamber S5 may move along the lower plate 117 and pass through a lower portion of the burner 120 (direction of arrow {circle around (6)}) and then be supplied to each flame hole 125 of the burner 120 as the secondary air. The secondary air may facilitate complete combustion of mixed gas in the flame holes 125.

In FIG. 19, arrow {circle around (3)} indicates a flow of heated air. Complete combustion is performed at the flame holes 125 by the secondary air described above to generate flames, and when the air of the combustion chamber S5 is heated by flame, the heated air may move through the heating flow path GP. The air heated through the heating flow path GP may be transferred to the heating chamber S2.

Referring to FIG. 11, the high temperature air transferred to the heating chamber S2 (direction of arrow {circle around (2)}) may be mixed with the air of the cooking chamber S1 suctioned to the heating chamber S2 by the circulation fan 93 (direction of arrow {circle around (1)}). The mixed air moves to the discharge chamber S3 and then may be supplied to the cooking chamber S1 through the discharge holes 75, 85 (direction of arrow {circle around (3)}). In FIG. 11, arrow {circle around (4)} indicates a direction in which external air moves to the lower portion of the heating device 100, arrow {circle around (5)} and arrow {circle around (6)} indicate air flows flowing along the first cooling flow path CP1 and the second cooling flow path CP2.

As described above, in this embodiment, the heating device 100 is arranged at the lower portion of the circulation device C circulating air of the cooking chamber S1, and is provided in a space separated from the circulation device C. This structure may prevent flames of the burner 120 from being affected by the fan even when the circulation fan 93 is operated. Accordingly, a separate stabilizer is unnecessary, and a burner reflector for protecting an inner wall of the cooking chamber S1 from flames is omitted.

More specifically, in embodiments disclosed herein, air heated in the heating device 100 has a low density and a large buoyancy as the air is heated and the volume increases, and the heated air may rise due to natural draft. Specific structure related to the circulation of air will be described hereinafter. Therefore, even when the circulation fan 93 is not operated, heated air may be supplied to the cooking chamber S1.

A part or portion of the air flowing along the first cooling flow path CP1 of the lower plate 117 may move toward the front plate 111 and then be introduced between the front plate 111 and the guide front surface 131. Next, the air may enter the first cooling flow path CP1 (direction of arrow {circle around (7)}) formed between the front plate 111 and the guide front surface 131 by the spacer 111a.

Further, external air may be introduced through upper second inlet IP2 of the second inlets IP2 (direction of arrow {circle around (5)}′). The introduced external air may flow along the second cooling flow path CP2 over the upper surface of the burner 120. A part or portion of the air introduced through the lower first inlet IP1 may also move along the upper surface of the burner 120 (direction of arrow {circle around (8)}), so the air may be mixed with the air introduced through the upper second inlet IP2.

The mixed air moves along the upper surface of the flame guide 140 to cool the flame guide 140. The air moving continuously along the second cooling flow path CP2 over the flame guide 140 may enter the second cooling outlet OP2 (direction of arrow {circle around (9)}). The air transferred toward the second cooling outlet OP2 through a gap between the guide end portion 145a of the flame guide 140 and the flow path entrance end 65a may rise and cool the frame lower surface 61 and the lower portion of the circulation device C.

FIG. 24 illustrates a burner according to an embodiment. A basic structure of burner 120 is described above and further description thereof has been omitted. A structure of the flame holes 125 will be described hereinafter. The multiple flame holes 125 may form a flame hole part or portion. The flame hole portion may be divided into multiple flame hole arrays A1, A2, and A3. Otherwise, the flame hole portion may be divided into multiple flame hole sets 125G1 and 125G2.

Referring to FIG. 24, the flame hole portion may include the multiple flame holes 125, and the multiple flame holes 125 may be arranged in a longitudinal direction of the burner body 121. Herein, the longitudinal direction of the burner body 121 is a direction in which the burner 120 is arranged in the combustion chamber S5, that is, a left-right or lateral direction based on FIG. 24. In other words, the longitudinal direction of the burner body 121 may be a direction in which premixed gas is transferred.

The flame holes 125 may include the multiple flame hole arrays A1, A2, and A3. The flame hole arrays A1, A2, and A3 may include the first flame hole array A1. The first flame hole array A1 may include multiple flame holes 125 arranged in one or a first direction along the burner body 121. Referring to FIG. 24, the first flame hole array A1 may include the multiple flame holes 125 spaced apart from each other.

The second flame hole array A2 may be arranged at an upper part or portion of the first flame hole array A1. The third flame hole array A3 may be arranged at a lower part or portion of the first flame hole array A1. The upper portion and the lower portion are based on FIG. 24, and the second flame hole array A2 and the third flame hole array A3 may be arranged at positions spaced apart from the first flame hole array A1 on the cylindrical burner body 121 in a circumferential direction. Referring to FIG. 27, the second flame hole array A2 may be arranged on a surface of the burner body 121 and at a position 125b1 spaced apart clockwise from the first flame hole array A1, 125a1. The third flame hole array A3 may be arranged on the surface of the burner body 121 and at a position 125c1 spaced apart counterclockwise from the first flame hole array A1, 125a1. This arrangement will be described hereinafter.

As described above, the flame hole portion may include the first flame hole array A1, the second flame hole array A2, and the third flame hole array A3. Each flame hole 125 of the first flame hole array A1, the second flame hole array A2, and the third flame hole array A3 may generate a flame. Flames generated from the first flame hole array A1, the second flame hole array A2, and the third flame hole array A3 may increase the firepower of the burner 120.

In describing the first flame hole array A1, the first flame hole array A1 may be open in a direction parallel to the bottom of the cooking chamber S5. In other words, the first flame hole array A1 may be open in a horizontal direction. In this embodiment, the first flame hole array A1 may be open toward the heating flow path GP. Accordingly, flames generated from the first flame hole array A1 are prevented from directly facing the bottom or a ceiling of the heating device 100.

The first flame hole array A1 may include a pair of first array main flame holes 125a. The pair of first array main flame holes 125a may be repeatedly arranged in the first flame hole array A1. Referring to the enlarged view of FIG. 24, two flame holes 125a1 and 125a2 of the pair of first array main flame holes 125a may be spaced apart from each other. The two main flame holes 125a1 and 125a2 with an interval therebetween may generate respective flames. The pair of first array main flame holes 125a may be repeated in the one or first direction to form the first flame hole array A1.

An auxiliary flame hole 125d may be arranged between two main flame holes 125a1 and 125a2. The auxiliary flame hole 125d may be arranged on a same straight line as the two main flame holes 125a1 and 125a2. The auxiliary flame hole 125d may allow a flame to spread between the two main flame holes 125a1 and 125a2. As the auxiliary flame hole 125d is formed, even when the two first array main flame holes 125a are spaced from each other, a flame may spread between the two main flame holes 125a1 and 125a2.

A diameter of the auxiliary flame hole 125d may be smaller than a diameter of each of the two main flame holes 125a1 and 125a2. The auxiliary flame hole 125d allows flames to spread between the main flame holes 125a1 and 125a2, so the diameter of the auxiliary flame hole 125d is relatively small. When the diameter of the auxiliary flame hole 125d is equal to the diameter of each of the main flame holes 125a1 and 125a2, a flame spreading velocity is increased, which may cause incomplete combustion or a shortage of the secondary air.

The second flame hole array A2 may be arranged at a position spaced apart from the first array main flame holes 125a in the circumferential direction of the burner body 121. As with the first flame hole array A1, the second flame hole array A2 may include multiple main flame holes 125b1 and 125b2 arranged in the one or first direction. The second flame hole array A2 generates multiple flames together with the first flame hole array A1, thereby increasing the firepower of the burner 120.

The second flame hole array A2 may include a pair of second array main flame holes 125b. The pair of second array main flame holes 125b may be repeatedly arranged in the second flame hole array A2. Referring to the enlarged view of FIG. 24, two flame holes 125b1 and 125b2 of the pair of second array main flame holes 125b may be spaced apart from each other. The two main flame holes 125b1 and 125b2 with an interval therebetween may generate respective flames. The pair of second array main flame holes 125b may be arranged at positions corresponding to the pair of first array main flame holes 125a. An interval I1 between the pair of second array main flame holes 125b may be an interval I1 between the pair of first array main flame holes 125a.

In this embodiment, unlike the pair of first array main flame holes 125a, the auxiliary flame hole 125d is omitted between the pair of second array main flame holes 125b. Accordingly, a secondary air inflow path AF1 is formed between the two main flame holes 125b1 and 125b2 of the second array main flame holes 125b so that the secondary air may flow through the secondary air inflow path AF1. Referring to FIG. 26, this view illustrates an arrow indicating a direction in which the secondary air flows inward through the secondary air inflow path AF1 formed between the two flame holes 125b1 and 125b2 of the pair of second array main flame holes 125b. Accordingly, even when the multiple flame hole arrays A1, A2, and A3 are arranged in parallel in the flame hole portion, the secondary air may be sufficiently supplied to the innermost first flame hole array A1.

The third flame hole array A3 may be arranged at a position spaced apart from the first array main flame holes 125a in the circumferential direction of the burner body 121. The third flame hole array A3 may be arranged opposite to the second flame hole array A2 with the first flame hole array A1 located therebetween. As with the first flame hole array A1, the third flame hole array A3 may include multiple main flame holes 125c1 and 125c2 arranged in the one or first direction. The third flame hole array A3 generates multiple flames together with the first flame hole array A1 and the second flame hole array A2, thereby increasing the firepower of the burner 120.

The third flame hole array A3 may include a pair of third array main flame holes 125c. The pair of third array main flame holes 125c may be repeatedly arranged in the third flame hole array A3. Referring to the enlarged view of FIG. 24, two main flame holes 125c1 and 125c2 of the pair of third array main flame holes 125c may be spaced apart from each other. The two main flame holes 125c1 and 125c2 with an interval therebetween may generate respective flames. The pair of third array main flame holes 125c may be located at positions corresponding to the pair of first array main flame holes 125a and the pair of second array main flame holes 125b. An interval between the two main flame holes 125c1 and 125c2 of the pair of second array main flame holes 125b may be equal to the interval between the pair of first array main flame holes 125a and the interval between the pair of second array main flame holes 125b. In other words, each first array main flame hole 125a, each second array main flame hole 125b, and each third array main flame hole 125c may be arranged along one imaginary curved line extending in the circumferential direction of the burner body 121.

In this embodiment, like the pair of second array main flame holes 125b, the auxiliary flame hole 125d is omitted between the pair of third array main flame holes 125c. Accordingly, a secondary air inflow path AF2 is formed between the two main flame holes 125c1 and 125c2 of the third array main flame holes 125c so that the secondary air may flow through the secondary air inflow path AF2. Referring to FIG. 26, this view illustrates an arrow indicating a direction in which the secondary air flows inward through the secondary air inflow path AF2 formed between the pair of third array main flame holes 125c. Accordingly, even when the multiple flame hole arrays A1, A2, and A3 are arranged in parallel in the flame hole portion, the secondary air may be sufficiently supplied to the innermost first flame hole array A1.

The first array main flame holes 125a, the second array main flame holes 125b, and the third array main flame holes 125c may have a same diameter. Then, the first array main flame holes 125a, the second array main flame holes 125b, and the third array main flame holes 125c may generate the same or a similar size of flames. When flames generated from the first array main flame holes 125a, the second array main flame holes 125b, and the third array main flame holes 125c are constant, merging of flames may be suppressed as much as possible.

FIG. 25 illustrates the first array main flame holes 125a, the second array main flame holes 125b, and the third array main flame holes 125c. The pair of first array main flame holes 125a, the pair of second array main flame holes 125b, the pair of third array main flame holes 125c, and the auxiliary flame hole 125d may form one flame hole set 125G1, 125G2. The flame hole sets 125G1, 125G2 are repeatedly arranged along the burner body 121, thereby providing the flame hole portion.

Each of the flame hole sets 125G1 and 125G2 has a roughly “H” form. As described above, flames may spread between the flame holes 125 of the H-shaped flame hole sets 125G1 and 125G2, and merging of flames may be suppressed. A process of flames spreading between the flame hole sets 125G1 and 125G2 will be described hereinafter.

FIG. 25 illustrates two flame hole sets 125G1 and 125G2. The flame hole sets 125G1 and 125G2 may be arranged repeatedly. For convenience of description, among the flame hole sets 125G1 and 125G2 as shown in FIG. 25, a left flame hole set is referred to as a first flame hole set 125G1, and a right flame hole set is referred to as a second flame hole set 125G2. The first flame hole set 125G1 and the second flame hole set 125G2 may have a same structure.

In describing based on the first flame hole set 125G1, in the first flame hole set 125G1, an interval I1 between the two main flame holes 125a1 and 125a2 of the first array main flame holes 125a may be wider than a circumferential interval 12 between the first array main flame holes 125a and the second array main flame holes 125b. In other words, the circumferential interval 12 between the first flame hole array A1 and the second flame hole array A2 may be narrower than the interval I1 between the two main flame holes 125a1 and 125a2 of the first array main flame holes 125a. Thus, flames may spread efficiently between the first flame hole array A1 and the second flame hole array A2. The interval between the two flame holes 125a1 and 125a2 of the first array main flame holes 125a is relatively wide, and flames may spread by the auxiliary flame hole 125d.

Further, in this embodiment, in the first flame hole set 125G1, the interval I1 between the two main flame holes 125a1 and 125a2 of the pair of first array main flame holes 125a may be wider than the circumferential interval 12 between the first array main flame holes 125a and the third array main flame holes 125c. Thus, flames may spread efficiently between the first flame hole array A1 and the third flame hole array A3.

An interval I4 between one or a first first array main flame hole 125a2 and another or a second first array main flame hole 125a1 of an adjacent set may be narrower than the interval I1 between the two main flame holes 125a1 and 125a2 of the first array main flame holes 125a. In other words, the interval I4 between the first array main flame hole 125a2 of the first flame hole set 125G1 and the second array main flame hole 125b1 of the second flame hole set 125G2, the two sets are adjacent to each other, is narrower than the interval I1 between the two main flame holes 125a1 and 125a2 of the first array main flame holes 125a. Thus, flames may spread between the adjacent two different flame hole sets 125G1 and 125G2.

In this embodiment, an interval I3 between one main flame hole 125a1 of the first array main flame holes 125a and the auxiliary flame hole 125d may be shorter than the interval I4 of the first array main flame hole 125a2 and the first array main flame hole 125a1 of another different set. In other words, the interval I4 between the first array main flame hole 125a2 of the first flame hole set 125G1 and the first array main flame hole 125a1 of the second flame hole set 125G2, the two set being adjacent to each other, is longer than the interval I3 between the first array main flame hole 125a1 and the auxiliary flame hole 125d. Thus, flames may be prevented from merging between the adjacent two different flame hole sets 125G1 and 125G2.

Referring to FIGS. 25 and 26, the flame hole sets 125G1 and 125G2 may have a structure symmetrical around an upper-lower or vertical axis and a left-right or lateral or horizontal axis based on the auxiliary flame hole 125d. As described above, the flame hole sets 125G1 and 125G2 in this embodiment may have a roughly “H” shape. As described above, the flame holes 125 of the H-shaped flame hole sets 125G1 and 125G2 may be arranged symmetrically around the left-right axis and the upper-lower axis based on the auxiliary flame hole 125d. This symmetrical structure may provide a flame-stabilizing structure of the flame holes 125 of the flame hole sets 125G1 and 125G2, thereby improving a performance of the burner 120.

Referring to FIG. 25, a process of flames spreading through the flame holes of the two flame hole sets 125G1 and 125G2 will be described. First, when a premixed gas is burned by the spark plug 122, a flame may be generated from the ignition flame hole 126. The ignition flame hole 126 may be arranged on an imaginary extension line that extends from the first flame hole array A1. Accordingly, flames of the ignition flame hole 126 may spread to the first flame hole array A1.

A flame of the ignition flame hole 126 may spread to the first array main flame holes 125a of the first flame hole set 125G1 in the flame hole sets 125G1 and 125G2. The flame may spread to the left first array main flame hole 125a1 of the first array main flame holes 125a. The flame of the first array main flame hole 125a1 may spread to the left second array main flame hole 125b1 of the second array main flame holes 125b (direction of arrow {circle around (1)}). The flame of the first array main flame hole 125a1 may spread to the left third array main flame hole 125c1 of the third array main flame holes 125c (direction of arrow {circle around (2)}).

In addition, the flame of the first array main flame hole 125a1 may spread to the auxiliary flame hole 125d (direction of arrow {circle around (3)}). The flame of the auxiliary flame hole 125d may spread to another adjacent first array main flame hole 125a, that is, the right first array main flame hole 125a2 (direction of arrow {circle around (4)}). Next, the flame of the first array main flame hole 125a2 may spread to the right second array main flame hole 125b2 of the second array main flame holes 125b (direction of arrow {circle around (5)}). The flame of the first array main flame hole 125a2 may spread to the right third array main flame hole 125c2 of the third array main flame holes 125c (direction of arrow {circle around (6)}).

All of the flame holes of the first flame hole set 125G1 may generate flames. The left second array main flame hole 125b1 may not allow a flame to spread directly to the right second array main flame hole 125b2. This is because the interval between the two second array main flame holes 125b1 and 125b2 is too wide to transmit a flame directly. Likewise, the left third array main flame hole 125c1 may not allow a flame to spread directly to the right third array main flame hole 125c2. Accordingly, in this embodiment, as a flame spreads sequentially to each of the flame holes of the first flame hole set 125G1, the flame may be maintained stably. Further, incomplete combustion may occur as the flame spreads at the same time, or an explosion noise during the spreading may be prevented.

All of the flame holes 125 of the first flame hole set 125G1 generate flames, and then the flames may spread to the second flame hole set 125G2. The right first array main flame hole 125a2 of the flame holes 125 of the first flame hole set 125G1 may transmit a flame to the left first array main flame hole 125a1 of the flame holes 125 of the second flame hole set 125G2 (direction of arrow {circle around (7)}).

As described above, the interval I4 between one first array main flame hole 125a2 and another first array main flame hole 125a1 of an adjacent set may be narrower than the interval I1 between the two main flame holes 125a1 and 125a2 of the first array main flame holes 125a, so a flame may spread. Of course, a flame may spread from the right second array main flame hole 125b2 of the flame holes 125 of the first flame hole set 125G1 to the left second array main flame hole 125b1 of the flame holes 125 of the second flame hole set 125G2. However, in the order in which a flame spreads, a speed at which a flame spreads from the right first array main flame hole 125a2 of the first flame hole set 125G1 to the left first array main flame hole 125a1 of the second flame hole set 125G2 is relatively faster.

Next, as described above, a flame may spread between the flame holes 125 of the second flame hole set 125G2. In other words, the flame of the first array main flame hole 125a1 may spread to the left second array main flame hole 125b1 of the second array main flame holes 125b (direction of arrow {circle around (8)}). At the same time, the flame of the first array main flame hole 125a1 may spread to the left third array main flame hole 125c1 of the third array main flame holes 125c (direction of arrow {circle around (9)}).

In addition, the flame of the first array main flame hole 125a1 may spread to the auxiliary flame hole 125d (direction of arrow {circle around (10)}). The flame of the auxiliary flame hole 125d may spread to another adjacent first array main flame hole 125a, that is, the right first array main flame hole 125a2 (direction of arrow {circle around (11)}). Next, the flame of the first array main flame hole 125a2 may spread to the right second array main flame hole 125b2 of the second array main flame holes 125b (direction of arrow {circle around (12)}). At the same time, the flame of the first array main flame hole 125a2 may spread to the right third array main flame hole 125c2 of the third array main flame holes 125c (direction of arrow {circle around (13)}).

All of the flame holes of the second flame hole set 125G2 may generate flames. Further, as the above-described process is repeated, flames may be generated from all of the flame holes 125 of the burner 120. As described above, in this embodiment, direct flame spreading may not occur between the two flame holes of the first array main flame holes 125a, the second array main flame holes 125b, and the third array main flame holes 125c. In other words, a flame spreads by a medium of the auxiliary flame hole 125d, or through the first array main flame holes 125a arranged at a central part or portion to the second array main flame holes 125b and the third array main flame holes 125c.

FIG. 26 illustrates a supply path of the secondary air required for combustion in the flame holes 125. As described above, the secondary air inflow path AF1 may be formed between the pair of second array main flame holes 125b to extend along the surface of the burner body 121 to the auxiliary flame hole 125d. Likewise, the secondary air inflow path AF2 may be formed between the pair of third array main flame holes 125c to extend along the surface of the burner body 121 to the auxiliary flame hole 125d. Further, a secondary air inflow path AF3 may be formed between the first flame hole set 125G1 and the second flame hole set 125G2 adjacent to each other. The secondary air may be transferred to the flame holes 125 through the secondary air inflow path AF1, AF2, AF3. Therefore, in this embodiment, the secondary air may be sufficiently supplied to the flame holes 125, and flames may be stably maintained.

FIG. 27 is a cross-sectional view of the burner 120. As illustrated in the drawing, based on the central portion of the burner 120, that is, the central portion of the gas flow path 121, the first flame hole array A1, 125a1 and the second flame hole array A2, 125b1 may be spaced apart from each other in the circumferential direction of the burner body 121. In this embodiment, the first array main flame hole 125a1 of the first flame hole array A1 and the second array main flame hole 125b1 of the second flame hole array A2 may be separated by an angle α between 15 and 25 degrees in the circumferential direction of the burner body 121. Further, the first array main flame hole 125a1 of the first flame hole array A1 and the third array main flame hole 125c1 of the third flame hole array A3 may be separated by an angle β between 15 to 25 degrees in the circumferential direction of the burner body 121. The flame hole arrays A1, A2, and A3 spaced apart from each other as described above may transmit flames from each other and prevent merging of flames.

FIG. 28, is a graph of a density of CO and initial combustion time changing according to the angle α between the first flame hole array A1 and the second flame hole array A2. The initial combustion time is the time from when the spark plug 122 is operated until all of the flame holes 125 generate flames. Therefore, it is advantageous to reduce the density of CO, and a short initial combustion time is advantageous.

As shown in the graph, when the angle α of the first flame hole array A1 and the second flame hole array A2 is increased, the density of CO is reduced. This is because a contact area with the secondary air is increased to reduce incomplete combustion, and merging of flames between the flame holes 125 is reduced to achieve an appropriate balance between gas injection speed and combustion speed. However, the angle α of the first flame hole array A1 and the second flame hole array A2 exceeds 25 degrees, there is no significant difference in the density of CO.

As the angle α between the first flame hole array A1 and the second flame hole array A2 is increased, the initial combustion time is increased. This is because the distance between the flame holes 125 increases and the flame-spreading time increases. Further, not illustrated in the drawing, when the angle α between the first flame hole array A1 and the second flame hole array A2 exceeds 25 degrees, there is a disadvantage that the noise of explosion when a flame spreads between the flame holes 125 increases. However, even when the angle α between the first flame hole array A1 and the second flame hole array A2 is lower than 15 degrees, there is no significant difference in the initial combustion time.

The angle α between the first flame hole array A1 and the second flame hole array A2 may be between 15 and 25 degrees along the circumferential direction of the burner body 121. Further, the angle β between the first flame hole array A1 and the third flame hole array A3 may be between 15 and 25 degrees in the circumferential direction of the burner body 121.

Referring to FIG. 27, in this embodiment, the flame hole portion is formed only in a partial region of the surface of the burner 120. More specifically, the burner body 121 may include a first region T1 facing a heated region where flames are generated from the flame hole portion, and a second region T2 having a phase difference of 180 degrees to the first region T1. The heated region may be the heating flow path GP.

The flame hole portion may be arranged in the first region T1. Based on the drawing, the flame hole portion may be formed only in the first region T1, that is, a left portion of the burner body 121. Accordingly, the firepower generated from the flame hole portion may be concentrated in the heated region, and it is possible to prevent a lower portion of the frame 60 around the heating device 100 from being damaged by high temperature heat or an enamel coating layer of the frame 60 from being damaged.

FIGS. 29 to 31 illustrate structure of a burner according to another embodiment. In describing components different from the above-described embodiment, in this embodiment, the flame hole portion may include multiple flame holes 125, and the multiple flame holes 125 may be arranged in a longitudinal direction of burner body 121. The longitudinal direction of the burner body 121 is a direction in which burner 120 is arranged in combustion chamber S5, that is, a left-right or lateral direction based on the drawings. In other words, the longitudinal direction of the burner body 121 may be a direction in which premixed gas is transferred.

The flame holes 125 may include the multiple flame hole arrays A1 and A2. The flame hole arrays A1 and A2 may include the first flame hole array A1. The first flame hole array A1 may include multiple flame holes 125 arranged in one or a first direction along the burner body 121. Referring to FIG. 29, the first flame hole array A1 may include the multiple flame holes 125 spaced apart from each other.

The second flame hole array A2 may be arranged at a lower part or portion of the first flame hole array A1. The lower portion is based on FIG. 29, and the second flame hole array A2 may be arranged at positions spaced apart from the first flame hole array A1 on the cylindrical burner body 121 in a circumferential direction. Referring to FIG. 31, the second flame hole array A2, 125b1 may be arranged on the surface of the burner body 121 and at a position spaced apart counterclockwise from the first flame hole array A1, 125a1.

The first flame hole array A1 may include a pair of first array main flame holes 125a. The pair of first array main flame holes 125a may be repeatedly arranged in the first flame hole array A1. Referring to the enlarged view of FIG. 29, the two main flame holes 125a1 and 125a2 of the pair of first array main flame holes 125a may be spaced apart from each other. The two main flame holes 125a1 and 125a2 with an interval therebetween may generate respective flames. The pair of first array main flame holes 125a may be repeated in the one or first direction to form the first flame hole array A1.

An auxiliary flame hole 125d may be arranged between the two main flame holes 125a1 and 125a2. The auxiliary flame hole 125d may be arranged on a same straight line as the pair of first array main flame holes 125a. The auxiliary flame hole 125d may allow a flame to spread between the two main flame holes 125a1 and 125a2 of the pair of first array main flame holes 125a. As described above, as the auxiliary flame hole 125d is formed, even when the two first array main flame holes 125a are spaced from each other, a flame may spread between the two main flame holes 125a1 and 125a2.

The second flame hole array A2 may include a pair of second array main flame holes 125b. The pair of second array main flame holes 125b may be repeatedly arranged in the second flame hole array A2. Referring to the enlarged view of FIG. 29, two flame holes 125b1 and 125b2 of the pair of second array main flame holes 125b may be spaced apart from each other. The two main flame holes 125b1 and 125b2 with an interval therebetween may generate respective flames. The pair of second array main flame holes 125b may be arranged at positions corresponding to the pair of first array main flame holes 125a. An interval between the pair of second array main flame holes 125b may be an interval between the pair of first array main flame holes 125a.

In this embodiment, unlike the pair of first array main flame holes 125a, the auxiliary flame hole 125d is omitted between the two main flame holes 125b1 and 125b2 of the pair of second array main flame holes 125b. Accordingly, the secondary air inflow path may be formed between the pair of second array main flame holes 125b, and the secondary air may flow through the secondary air inflow path. Accordingly, even when the multiple flame hole arrays A1 and A2 are arranged in parallel in the flame hole portion, the secondary air may be sufficiently supplied to the inner first flame hole array A1.

The first array main flame holes 125a and the second array main flame holes 125b may have a same diameter. The first array main flame holes 125a and the second array main flame holes 125b may generate the same or similar size of flames. When flames generated from the first array main flame holes 125a and the second array main flame holes 125b are constant, merging of flames may be suppressed as much as possible.

FIG. 30 illustrates the first array main flame holes 125a and the second array main flame holes 125b. The pair of first array main flame holes 125a, the pair of second array main flame holes 125b, and the auxiliary flame hole 125d may form one flame hole set 125G1, 125G2. The flame hole set 125G1, 125G2 may be repeatedly arranged along the burner body 121, thereby providing the flame hole portion.

The flame hole set 125G1, 125G2 has a roughly “U” form. As described above, flames may spread between the flame holes 125 of the U-shaped flame hole set 125G1, 125G2, and merging of flames may be suppressed. A process of flames spreading between the flame hole set 125G1, 125G2 will be described hereinafter.

FIG. 30 illustrates two flame hole sets 125G1 and 125G2. The flame hole sets 125G1 and 125G2 may be arranged repeatedly. For convenience of description, among the flame hole sets 125G1 and 125G2 as shown in FIG. 30, the left flame hole set is referred to as a first flame hole set 125G1, and the right flame hole set is referred to as a second flame hole set 125G2. The first flame hole set 125G1 and the second flame hole set may have a same structure.

In describing based on the first flame hole set 125G1, in the first flame hole set 125G1, the interval I1 between the two flame holes 125a1 and 125a2 of the pair of first array main flame holes 125a may be wider than a circumferential interval 12 between the first array main flame holes 125a and the second array main flame holes 125b. In other words, the circumferential interval 12 between the first flame hole array A1 and the second flame hole array A2 may be narrower than the interval I1 between the two flame holes 125a1 and 125a2 of the first array main flame holes 125a. Thus, flames may spread efficiently between the first flame hole array A1 and the second flame hole array A2. An interval between the pair of first array main flame holes 125a of the first flame hole array A1 is relatively wide, but the auxiliary flame hole 125d may enable a flame to spread.

An interval I4 between one or a first first array main flame hole 125a2 and another or a second first array main flame hole 125a1 of an adjacent set may be narrower than the interval I1 between the two main flame holes 125a1 and 125a2 of the pair of first array main flame holes 125a. In other words, the interval I4 between the first array main flame hole 125a2 of the first flame hole set 125G1 and the first array main flame hole 125a1 of the second flame hole set 125G2, the two sets are adjacent to each other, is narrower than the interval I1 between the two main flame holes 125a1 and 125a2 of the first array main flame holes 125a. Thus, flames may spread between the adjacent two different flame hole sets 125G1 and 125G2.

In this embodiment, the interval I3 between one main flame hole 125a1 of the pair of first array main flame holes 125a and the auxiliary flame hole 125d may be shorter than the interval I4 of the first array main flame hole 125a2 and the first array main flame hole 125a1 of another different set. In other words, the interval I4 between the first array main flame hole 125a2 of the first flame hole set 125G1 and the first array main flame hole 125a1 of the second flame hole set 125G2, the two set being adjacent to each other, is longer than the interval I3 between the first array main flame hole 125a1 and the auxiliary flame hole 125d. Thus, flames may be prevented from merging between the adjacent two different flame hole sets 125G1 and 125G2.

Referring to FIG. 30, the flame hole sets 125G1 and 125G2 may have a structure symmetrical about the left-right or lateral axis based on the auxiliary flame hole 125d. As described above, the flame hole sets 125G1 and 125G2 in this embodiment may have a roughly “U” shape. As described above, the flame holes 125 of the U-shaped flame hole sets 125G1 and 125G2 may be arranged to be symmetrical about the left-right or lateral axis based on the auxiliary flame hole 125d.

Referring to FIG. 30, a process of flames spreading through the flame holes of the two flame hole sets 125G1 and 125G2 will be described. First, when the premixed gas is burned by the spark plug 122, a flame may be generated from the ignition flame hole 126. The ignition flame hole 126 may be arranged on an imaginary extension line that extends from the first flame hole array A1. Accordingly, flames of the ignition flame hole 126 may spread to the first flame hole array A1.

A flame of the ignition flame hole 126 may spread to the first array main flame holes 125a of the first flame hole set 125G1 in the flame hole sets 125G1 and 125G2. The flame may spread to the left first array main flame hole 125a1 of the first array main flame holes 125a. The flame of the first array main flame hole 125a1 may spread to the left second array main flame hole 125b1 of the second array main flame holes 125b (direction of arrow {circle around (1)}). In addition, a flame of the first array main flame hole 125a1 may spread to the auxiliary flame hole 125d (direction of arrow {circle around (2)}).

The auxiliary flame hole 125d may allow the flame to spread to another different first array main flame hole 125a2, that is, the right first array main flame hole 125a2 (direction of arrow {circle around (3)}). Next, the flame of the first array main flame hole 125a2 may spread to the right second array main flame hole 125b2 of the second array main flame holes 125b (direction of arrow {circle around (4)}). Then, all of the flame holes of the first flame hole set 125G1 may generate flames.

The left second array main flame hole 125b1 may not allow a flame to spread directly to the right second array main flame hole 125b2. This is because the interval between the two second array main flame holes 125b1 and 125b2 is too wide to transmit a flame directly. Accordingly, in this embodiment, as a flame spreads sequentially to each of the flame holes of the first flame hole set 125G1, the flame may be maintained stably. Furthermore, incomplete combustion may occur as the flame spreads at the same time, or explosion noise during the spreading may be prevented.

As described above, the interval I4 between one first array main flame hole 125a2 and another first array main flame hole 125a1 of an adjacent set may be narrower than the interval I1 between the two main flame holes 125a1 and 125a2 of the pair of first array main flame holes 125a, and the spreading of flame may be achieved. Of course, a flame may spread from the right second array main flame hole 125b2 of the flame holes 125 of the first flame hole set 125G1 to the left second array main flame hole 125b1 of the flame holes 125 of the second flame hole set 125G2. However, in the order in which a flame spreads directly, a speed at which a flame spreads from the right first array main flame hole 125a2 of the first flame hole set 125G1 to the left first array main flame hole 125a1 of the second flame hole set 125G2 is faster.

In addition, the flame of the first array main flame hole 125a1 may spread to the auxiliary flame hole 125d (direction of arrow {circle around (7)}). The flame of the auxiliary flame hole 125d may spread to another adjacent first array main flame hole 125a2, that is, the right first array main flame hole 125a2 (direction of arrow {circle around (8)}). Next, the flame of the first array main flame hole 125a2 may spread to the right second array main flame hole 125b2 of the second array main flame holes 125b (direction of arrow {circle around (9)}). Then, all of the flame holes of the second flame hole set 125G2 can generate flames.

As the above-described process is repeated, flames may be generated from all of the flame holes 125 of the burner 120. As described above, in this embodiment, direct flame spreading may not occur between the two flame holes constituting the first array main flame holes 125a and the second array main flame holes 125b. In other words, a flame spreads by a medium of the auxiliary flame hole 125d, or through the first array main flame holes 125a arranged at a central part or portion to the second array main flame holes 125b.

FIG. 31 illustrates a cross-sectional view of the burner 120. As illustrated in the drawing, based on the central portion of the burner 120, that is, the central portion of the gas flow path 121, the first flame hole array A1, 125a1 and the second flame hole array A2, 125b1 may be spaced apart from each other in the circumferential direction of the burner body 121. In this embodiment, the first array main flame hole 125a1 of the first flame hole array A1 and the second array main flame hole 125b1 of the second flame hole array A2 may be separated by an angle β between 15 to 25 degrees in the circumferential direction of the burner body 121. The flame hole arrays A1 and A2 spaced apart from each other as described above may transmit flames from each other and prevent the merging of flames. This angle is described in the graph of FIG. 28 in the above-described embodiment, and thus, description thereof has been omitted.

Embodiments disclosed herein solve problems of the related art as described above, and provide high heat power with multiple arrays of flame holes and to allow enough secondary air to flow between the flame holes of the multiple arrays at the same time.

Embodiments disclosed herein concentrate sufficient firepower with multiple flame hole arrays facing in one direction even when a linear tube-type burner is provided to be biased toward an outer portion of a cooking chamber.

Embodiments disclosed herein facilitate spreading of flames and suppress generation of harmful gases by spacing multiple arrays including flame holes from each other at a right angle.

Embodiments disclosed herein arrange a burner in a separate space separately from a circulation device circulating air in a cooking chamber.

Embodiments disclosed herein supply air heated by a burner into a cooking chamber even when a circulation fan is not operated.

Embodiments disclosed herein provide a burner that may include a burner body in which a gas flow path is formed, and a flame hole part or portion open in the burner body. The flame hole part may be connected to the gas flow path to spout gas. The flame hole part may include a first flame hole array in which multiple flame holes are arranged in one or a first direction. The flame hole part may include a second flame hole array spaced apart from the first flame hole array in a circumferential direction of the burner body. The first flame hole array may include a pair of first array main flame holes spaced apart from each other, the pair of first array main flame holes being arranged repeatedly. An auxiliary flame hole may be provided between the pair of first array main flame holes and the auxiliary flame hole may have a diameter smaller than a diameter of each first array main flame hole. The multiple flame hole arrays may provide high heat power, thereby improving heating efficiency of the burner.

A pair of second array main flame holes may be repeatedly arranged in the second flame hole array. A secondary air inflow path may be formed between the pair of second array main flame holes to extend to the auxiliary flame hole along the surface of the burner body. Accordingly, the main flame holes included in the multiple flame hole arrays may be spaced apart from each other so that the secondary air may be sufficiently supplied therebetween.

A pair of second array main flame holes may be repeatedly arranged in the second flame hole array. An interval between the pair of second array main flame holes may be an interval between the pair of first array main flame holes.

In addition, the burner body may be in the form of a linear tube that extends in one direction. The flame hole part may be provided in one direction along the surface of the burner body.

Further, a circumferential distance between the first flame hole array and the second flame hole array may be shorter than an interval between the pair of main flame holes. Furthermore, an interval between the pair of first array main flame holes and another adjacent pair of first array main flame holes may be shorter than an interval between the two main flame holes constituting the pair first array main flame holes.

The burner body may include a third flame hole array spaced apart from the first flame hole array in the circumferential direction of the burner body. The third flame hole array may include multiple flame holes arranged in one direction. The third flame hole array may be arranged opposite to the second flame hole array with the first flame hole array located therebetween.

The flame hole part may include multiple flame hole sets arranged repeatedly along the burner body. The flame hole sets may include a pair of first array main flame holes constituting the first flame hole array. The flame hole sets may include a pair of second array main flame holes constituting the second flame hole array. The flame hole sets may include a pair of third array main flame holes constituting the third flame hole array. The flame hole sets may include the auxiliary flame hole arranged between the pair of first array main flame holes.

The first array main flame holes, the second array main flame holes, and the third array main flame holes may have the same diameter. In addition, each first array main flame hole, each second array main flame hole, and each third array main flame hole may be respectively arranged on an imaginary curved line extending in the circumferential direction of the burner body.

Furthermore, the flame hole sets may have a structure symmetrical around an upper-lower axis or vertical and a left-right or lateral or horizontal axis based on the auxiliary flame hole.

Based on a center part or portion of the gas flow path, the first flame hole array and the second flame hole array may form an included angle between 15 and 25 degrees in the circumferential direction of the burner body.

An interval between one of the pair of main flame holes and the auxiliary flame hole may be shorter than a between the pair of main flame holes and another adjacent pair of main flame holes.

The burner body may be arranged at a lower portion of a bottom of a cooking chamber. The first flame hole array may be open in a direction parallel to the bottom of the cooking chamber.

The burner body may include a first region facing a heated region heated by a flame generated from the flame hole part, and a second region having a phase difference of 180 degrees with respect to the first region. The flame hole part may be arranged in the first region.

The burner body may include an ignition flame hole arranged closer to an ignition device than the flame hole part. The ignition flame hole may be arranged on an imaginary extension line that extends from the first flame hole array.

As described above, the cooking appliance according to embodiments disclosed herein has at least the following advantages.

The burner may include the flame hole part or portion including the multiple flame holes, and the flame hole part may include multiple flame hole arrays. The multiple flame hole arrays may provide high heat power, thereby improving a heating efficiency of the burner.

The main flame holes included in the multiple flame hole arrays may be spaced apart from each other so that the secondary air may be sufficiently supplied therebetween. Further, the auxiliary flame hole may be provided between the main flame holes, and even when the main flame holes are spaced apart from each other, flames may be induced to spread efficiently between the main flame holes by the auxiliary flame. As described above, according to embodiments disclosed herein, as the main flame holes are sufficiently spaced apart from each other, the secondary air may be supplied and the flames may efficiently spread. Accordingly, with the supply of high heat power and reduction of harmful gases, a quality of the cooking appliance may be improved.

In addition, according to embodiments disclosed herein, the auxiliary flame hole may be arranged between the pair of first array main flame holes constituting the first flame hole array, and the auxiliary flame hole may be omitted between the pair of second array main flame holes constituting the second flame hole array. Accordingly, the secondary air inflow path may be formed between the pair of second array main flame holes to extend to the auxiliary flame hole along the surface of the burner body. Then, even when the multiple flame holes are arranged with a narrow interval, the path for inflow of the secondary air is secured, and a stable flame may be generated and maintained.

Further, according to embodiments disclosed herein, the multiple flame holes may constitute the flame hole sets. The flame hole sets may be arranged symmetrically to each other with the auxiliary flame hole located therebetween. The symmetry structure may allow a flame-stabilizing structure of the flame holes constituting the flame hole sets. As described above, the flame-stabilizing structure of the flame hole sets may maintain flames more stably, thereby improving a performance of the burner.

In addition, according to embodiments disclosed herein, the flame hole part of the burner may be provided in the first region facing the heating space. The flame hole part arranged only in one direction may intensively heat air in the heating space. Accordingly, even when the burner is provided to be biased toward the outer portion of the cooking chamber, enough firepower is concentrated by the multiple flame hole arrays facing in one direction, and enough firepower may be provided.

Further, according to embodiments disclosed herein, the multiple arrays constituting the flame hole part may be spaced apart from each other at a right angle. As described above, the multiple arrays spaced at the right angle may facilitate spreading of flames to reduce an initial combustion time and suppress generation of harmful gases at the same time.

Furthermore, in embodiments disclosed herein, the burner may be arranged at a lower portion of the circulation device circulating air of the cooking chamber and may be provided inside of the burner case, which that is a space independent from the circulation device. With this structure, even when the circulation fan of the circulation device is operated, a flame of the burner is not affected by the fan, so a stabilizer is not necessary, and a burner reflector for protecting the inner wall of the cooking chamber from the flame may be omitted. The number of components and assembly work hours of the cooking appliance may be reduced, and manufacturing costs lowered.

Furthermore, the burner is arranged into an independent space separated from the circulation fan, so there is no risk in which the combustion of the burner becomes unstable by operation of the circulation fan. Accordingly, the burner can generate more stable flames, and therefore, a cooking performance of the cooking appliance may be improved.

In addition, the circulation fan is free from combustion instability of the burner, so an air flow of the circulation fan may be changed during the combustion of the burner. Which enables the cooking appliance to provide various cooking methods for a user.

Further, in embodiments disclosed herein, the circulation device and the heating device may have different heights and be arranged in a heightwise (vertical) direction. A flow path in the circulation device and a flow path of the heating device may form a vertically continuous flow path. Air heated by the heating device may be raised along the continuous flow path by natural draft and then may be supplied into the cooking chamber. Therefore, even when the circulation fan is not operated, heated air may be supplied to the cooking chamber, so the cooking appliance may provide more various cooking modes.

Although embodiments have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit as disclosed in the accompanying claims. Therefore, the embodiments described above have been described for illustrative purposes, and should not be intended to limit the technical spirit, and the scope and spirit are not limited to the embodiments. The protective scope should be interpreted by the accompanying claims, and all technical spirits within the equivalent scope should be interpreted as being included in the scope and spirit.

It will be understood that when an element or layer is referred to as being “on” another element or layer, the element or layer can be directly on another element or layer or intervening elements or layers. In contrast, when an element is referred to as being “directly on” another element or layer, there are no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

Spatially relative terms, such as “lower”, “upper” and the like, may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “lower” relative to other elements or features would then be oriented “upper” relative to the other elements or features. Thus, the exemplary term “lower” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Embodiments are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments disclosed herein should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

BURNER AND COOKING APPLIANCE HAVING BURNER

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