Patent Grant
7308852
The present invention relates to a cooking oven that cooks foods with heat by application of a hot air stream thereto.
Cooking ovens such as convention ovens and hot-air-impingement ovens that cook foods with heat by forming a circulated current of hot air stream inside a cooking chamber in which foods are placed, are well known and widely used. Published documents such as, to name a few, Japanese Utility Model Published No. H6-23841 and Japanese Patent Applications Laid-Open Nos. H9-145063, Hi1-166737, 2000-329351, and 2001-311518 disclose examples of hot-air-circulation cooking ovens. On the other hand, Japanese Patent Published No. H9-503334 discloses an example of a hot-air-impingement cooking oven. Among these examples, the cooking oven disclosed in Japanese Patent Application Laid-Open No. 2001-311518 has a heater arranged inside a duct through which a air stream is sent to a cooking chamber.
Now, as the basis of the present invention, the construction of a hot-air-circulation cooking oven will be described with reference to
The cooking oven 1 has a cabinet in the shape of a rectangular parallelepiped. Inside the cabinet 10, there is formed a cooking chamber 11 in the shape of a rectangular parallelepiped. The top and bottom of the cooking chamber 11 are formed by a ceiling wall 12 and a floor wall 13, respectively. Of the four sides of the cooking chamber 11, three are formed by a rear inner wall 14, a left inner wall 15, and a right inner wall 16, respectively, and the fourth side is formed by a freely openable door 17. The door 17 and all the walls of the cooking chamber 11 are heat-insulated.
The cooking chamber 11, which is enclosed from six sides by the walls and the door as described above, has the following interior dimensions: 230 mm high, 408 mm wide, and 345 mm deep. It should be understood that all the values given as dimensions, speeds, temperatures, and the like in the present specification are merely preferable examples and are not meant to limit the scope of the present invention in any way.
Outside the rear inner wall 14, there is installed a blower 20. The blower 20 has a centrifugal fan 22 arranged inside a fan casing 21. This centrifugal fan 22 is rotated in the forward and backward directions by a reversible-rotation motor, which will be described later. The fan casing 21 is of a type that branches into two directions, and has an upper discharge port 23 and a side discharge port 24. The upper discharge port 23 connects to an upper duct 25 provided outside the ceiling wall 12. The side discharge port 24 connects to a side duct 26 provided outside the left inner wall 15.
The upper duct 25 has an upper blowout port 30 open to the cooking chamber 11. The side duct 26 has a side blowout port 31 open to the cooking chamber 11. In the rear inner wall 14, there is formed a suction port 32 of the blower 20. The upper blowout port 30 is formed by a group of small cylindrical holes each 11 mm across. The side blowout port 31 and the suction port 32 are each formed by a group of small holes each 5 mm across.
As shown in
On the floor wall 13, there is arranged a turntable 50 on which to place foods. On the turntable 50 is placed a supporting means such as a grill or rack that suits the kind of food placed. Reference number 51 represents a turntable drive motor.
The cooking oven 1 operates as follows. First, the door 17 is opened. Then, among different types of supporting means such as grills and racks, one that suits the intended kind of food is placed on the turntable 50. On this supporting means, foods are placed directly or using a container. Then, the door 17 is closed.
After the door 17 is closed, cooking conditions are entered via the operation panel 44. Based on the thus entered cooking conditions, the controller 43 selects the optimum among a plurality of pre-programmed cooking methods. The controller 43 then drives the blower 20, upper heater 40, side heater 41, microwave heating device 42, and turntable drive motor 51 to start cooking.
For example, in a case where roasted chicken is prepared, a grill is placed on the turntable 50, and a chunk of meat is placed on the grill. Then, the door 17 is closed, and then, from the menu displayed on the operation panel 44, “roasted chicken” is selected. Now, the controller 43 operates the blower 20, upper heater 40, side heater 41, microwave heating device 42, and turntable drive motor 51 in a mode for preparing “roasted chicken.”
The upper heater 40 has a power rating of 1,700 W, and the side heater 41 has a power rating of 1,200 W. Out from each of the upper blowout port 30 and the side blowout port 31 blows a hot air stream having a temperature of 300° C. or more as measured at those ports. The controller 43 controls the blower 20 in such a way that the air stream blown out from the upper blowout port 30 has a air stream speed of 65 km/h or more, and that the air stream blown out from the side blowout port 31 has a air stream speed of 30 km/h or less. The turntable 50 is rotated at a rotation rate of 6 rpm.
In the case described above, heating cooking is achieved by a hot-air-impact method whereby a high-speed hot air stream is blown onto foods. This permits fast cooking of the chunk of meat. The temperature inside the cooking chamber 11 is automatically adjusted at the target temperature entered via the operation panel 44. The upper limit of the target temperature is 300° C.
Next, how sponge cake is prepared will be described. A rack is placed on the turntable 50. Then, dough to be cooked into sponge cake is placed on the turntable 50 and also on the rack. The door 17 is closed, and, from the menu displayed on the operation panel 44, “sponge cake” is selected. Now, the controller 43 operates the blower 20, upper heater 40, side heater 41, microwave heating device 42, and turntable drive motor 52 in a mode for preparing “sponge cake.” Also here, the turntable 50 is rotated at a rotation rate of 6 rpm.
Here, however, the controller 43 controls the blower 20 in such a way that a hot air stream having a air stream speed of 30 km/h or less blows out from the upper blowout port 30, and that a hot air stream having a air stream speed of 40 km/h or less blows out from the side blowout port 31. In this case, heating cooking is achieved by two-stage hot-air-circulation method, and this permits the dough placed on the turntable 50 and on the rack to be each cooked into fluffy sponge cake. The hot air stream that blows from above has a low speed, and thus does not deform by its pressure the dough in the process of rising.
In heating cooking, a hot air stream or a microwave may be used singly, or they may be generated simultaneously so that heating is achieved by their combined effect. Whether to use the effect of a hot air stream or a microwave alone or their combined effect is determined by a cooking program or through selection by the user.
The cooking oven 1 described above can cope with various kinds of food and various methods of cooking by adjusting the ratio of the volumes of air stream blown out by the blower 20, the volumes of air stream themselves, and the air stream speeds, and by adjusting the amounts of heat generated by the upper and side heaters 40 and 41 and the output of the microwave heating device 42.
As cooking is performed on the cooking oven 1 described above, foods release oil, fat, and odor substances. Such oil and fat, in the form of greasy fumes, soil the interior of the cooking chamber and ducts. They also settle on foods and spoil the flavor thereof. Odor substances, when exposed to heat, deteriorate. Such deteriorated odor substances, when they settle on foods, spoil the flavor thereof.
To overcome these inconveniences, proposals have conventionally been made to decompose greasy fumes and odor substances with a catalyst. For example, Japanese Patent Application Laid-Open No. H4-62324 discloses a construction wherein a deodorizing catalyst and a catalyst heating means are arranged inside a container in which food is heated. Japanese Patent Application Published No. 2000-510568 discloses a recirculation-type cooking oven provided with a catalyst converter. Japanese Patent Application Laid-Open No. HI0-202112 discloses a cooking oven wherein a catalyst coating is applied on interior paint.
An object of the present invention is to provide a cooking oven that permits a catalyst to function satisfactorily and that can decompose greasy fumes and odor substances with high efficiency.
To achieve the above object, according to the present invention, a cooking oven is constructed as follows. The cooking oven has a blowout port and a suction port for passage of a hot air stream provided inside a cooking chamber and has a blower and a heat source for producing the hot air stream provided outside the cooking chamber so as to produce a circulated hot air stream inside the cooking chamber so that foods are cooked with heat by the circulated air stream. In this cooking oven, a catalyst block for decomposing substances released from foods and a heat source for heating the catalyst block are arranged inside the duct through which the hot air stream is fed to the blowout port. The heat source is so arranged as to face a plurality of faces of the catalyst block. With this construction, the catalyst block receives radiant heat from a plurality of directions, and thus quickly reaches the temperature that permits the catalyst to function. This permits the catalyst to start to function at an early stage. Moreover, of the plurality of faces of the catalyst block, one is made to face in the direction from which the circulated air stream blows. Thus, the circulated air stream heated by the heat source flows through the catalyst block. The catalyst block is heated from both inside and outside, and thus quickly reaches the temperature that permits the catalyst to function. In addition, of the plurality of faces of the catalyst block, another, i.e., one other than that facing in the direction from which the circulated air stream blows, is a face opposite thereto. Thus, not only the face that the circulated air stream blows directly onto but also the face opposite thereto is heated. This permits the catalyst to function satisfactorily irrespective of whether it is located on the upstream or downstream side of the air stream.
According to the present invention, a cooking oven is constructed as follows. The catalyst block is held by a fitting member in such a way as not to make contact with an interior wall surface of the duct. With this construction, the catalyst block does not make contact with an interior wall surface of the duct, and thus the heat of the catalyst block does not conduct to the walls of the duct.
According to the present invention, a cooking oven is constructed as follows. The cooking oven has a blowout port and a suction port for passage of a hot air stream provided inside a cooking chamber and has a blower and a heat source for producing the hot air stream provided outside the cooking chamber so as to produce a circulated hot air stream inside the cooking chamber so that foods are cooked with heat by the circulated air stream. In this cooking oven, catalyst paint for decomposing substances released from foods is applied to at least part of an interior wall surface of the duct through which the hot air stream is fed to the blowout port. With this construction, while the hot air stream is passing through the duct, substances released from foods are decomposed by the catalyst paint. Thus, even in a case where there is only a limited area for the arrangement of the catalyst, it is possible to exploit an interior wall surface of the duct to secure a sufficient contact-area between the catalyst and air stream.
According to the present invention, a cooking oven is constructed as follows. The cooking oven has a blowout port and a suction port for passage of a hot air stream provided inside a cooking chamber and has a blower and a heat source for producing the hot air stream provided outside the cooking chamber so as to produce a circulated hot air stream inside the cooking chamber so that foods are cooked with heat by the circulated air stream. In this cooking oven, a catalyst block for decomposing substances released from foods and a heat source for heating the catalyst block are arranged inside the duct through which the hot air stream is fed to the blowout port. The catalyst block is fitted at a distance from an interior wall surface of the duct. Moreover, catalyst paint for decomposing substances released from foods is applied to at least part of an interior wall surface of the duct. With this construction, the catalyst paint complements the function of the catalyst block, resulting in high-level decomposition.
Arranging the catalyst block in such a way as to completely obstruct the duct results in a high airflow resistance through the duct. This leads to a reduced amount of hot air stream or, if the desired amount of air stream is to be maintained, necessitates a blower with higher performance. This can be avoided by securing a gap between the catalyst block and an interior wall surface of the duct. Even when a gap is secured between the catalyst block and an interior wall surface of the duct to permit an air stream to pass therethrough in this way, unwanted substances contained in that air stream are decomposed by the catalyst paint. This helps obtain high-level decomposition performance.
According to the present invention, the cooking oven constructed as described above is constructed as follows. The surface to which the catalyst paint is applied has surface irregularities. With this construction, it is possible to increase the contact area between the catalyst paint surface and the air stream and thereby obtain still higher decomposition performance.
According to the present invention, the cooking oven constructed as described above is constructed as follows. Wave-shaped surface irregularities are formed on the interior wall surface of the duct. Of the slanted surfaces forming the surface irregularities, those facing in the direction from which the air stream blows are long and those facing in the direction opposite thereto are short. With this construction, it is possible to achieve efficient contact between the air stream and the catalyst paint surface and thereby obtain even higher decomposition performance.
According to the present invention, the cooking oven constructed as described above is constructed as follows. The surface irregularities are formed as ridges or grooves aligned along the air stream. With this construction, it is possible to increase the contact area between the catalyst paint surface and the air stream without diminishing the flow speed of the air stream. This makes it possible to obtain high-level decomposition performance even when the amount of hot air stream is large.
According to the present invention, the cooking oven constructed as described above is constructed as follows. The catalyst paint is applied to a air-stream-regulating plate provided inside the duct for regulating the air stream flowing toward the blowout port. With this construction, the air stream surely makes contact with the catalyst paint, permitting the catalyst to function satisfactorily.
According to the present invention, a cooking oven is constructed as follows. The cooking oven has a blowout port and a suction port for passage of a hot air stream provided in a wall of a cooking chamber and has a blower and a duct provided outside the cooking chamber, the blower sucking in air through the suction port and the duct directing the air blown out from the blower to the blowout port and heating the air with a heater incorporated therein, so as to produce a circulated hot air stream inside the cooking chamber so that foods are cooked with heat by the circulated air stream. In this cooking oven, a catalyst block for decomposing substances released from the foods is arranged inside the duct, and the distribution of the amount of heat generated by the heater within a cross section of the duct is so set as to be commensurate with the distribution of the amount of air stream within that cross section so that an increasingly large amount of heat is generated as there is an increasingly large amount of air stream. With this construction, the catalyst block is quickly heated by the hot air stream that flows through the duct, and thus the catalyst starts to function satisfactorily at an early stage. Moreover, the air flowing through that part of the cross section of the duct where the amount of air stream is large is given a commensurately large amount of heat. This helps achieve appropriate distribution of the amount of air stream and the amount of heat generated, resulting in efficient heating of air.
According to the present invention, the cooking oven constructed as described above is constructed as follows. The duct has a bent portion at a midpoint thereof. The heater is arranged at or on the downstream side of the bent portion, and the distribution of the amount of heat generated by the heater is so set that an increasingly large amount of heat is generated from the inner side to the outer side of the bent portion. With this construction, the large amount of air stream that flows at the outer side of the bent portion of the duct is given a commensurately large amount of heat. This helps achieve, in the duct having the bent portion, appropriate distribution of the amount of air stream and the amount of heat generated, resulting in efficient heating of air.
According to the present invention, the cooking oven constructed as described above is constructed as follows. The catalyst block is so arranged as to lie lopsided toward the side of a cross section of the duct where the amount of heat generated by the heater is larger. With this construction, the catalyst block is heated quickly, and is kept at a high temperature. This permits the catalyst to function fully.
According to the present invention, the cooking oven constructed as described above is constructed as follows. The catalyst block is fitted to an interior wall of the duct at the side thereof where the amount of heat generated by the heater is larger. With this construction, through heat conduction by way of the walls of the duct in addition to through direct heat radiation, the catalyst block is heated efficiently.
Hereinafter, a first embodiment of a cooking oven according to the invention will be described with reference to
As shown in
As the catalyst is used one based on a precious metal such as platinum or palladium or one based on manganese such as MnO, MnO2, or Mn perovskite. To make the carrier block 71 support the catalyst, the former is painted, impregnated, or treated in any other manner with the latter depending on the material of the carrier block 71.
The catalyst block 70 needs to be used in a temperature range that permits it to function satisfactorily. To achieve this, as a heat source for heating the catalyst block 70, there is provided a catalyst heater. The upper heater 40, which is the main heat source for producing the hot air stream, is shared as the catalyst heater. In the first embodiment, the upper heater 40 is realized with a sheath heater, and part of it is laid near the catalyst block 70 so as to serve as the catalyst heater 73.
The catalyst block 70 is arranged in such a way that the air stream passes through the inside of the tubular vent ports 72, i.e., in such a way that the length direction of the block as a whole is perpendicular to the air stream. This arrangement is shown in
The catalyst block 70 is fitted to an interior wall surface of the upper duct 25, at a distance secured therefrom, by a metal fitting member 80 shaped as shown in
When the catalyst block 70 is inserted in the frame portion 81 as shown in
The fitting member 80, with the catalyst block 70 held therein, is then, as shown in
The heat generated by the catalyst heater 73 heats not only the catalyst block 70 but also the air stream passing through the upper duct 25. Thus, the air stream heated by the catalyst heater 73 is further heated by the upper heater 40 so as to reach a desired temperature.
Catalyst paint 74 is applied (see
Also inside the side duct 26, there are provided a catalyst block and a catalyst heater. As in the upper duct 25, the side heater 41, which is the main heat source for producing the hot air stream, is realized with a sheath heater, and part of it is laid near the catalyst block so as to serve as the catalyst heater. The catalyst block in the side duct 26 is fixed by a fitting member similar to the fitting member 80. The fitting member is fixed to the left inner wall 15.
Catalyst paint similar to that used in the upper duct 25 is applied to the interior wall surfaces of the side duct 26, starting around the downstream-side end of the catalyst block.
In
The cooking oven 1 of the first embodiment operates as follows. When heating cooking is started, air is sucked out of the cooking chamber 11 into the blower 20, and is sent to the upper duct 25 and the side duct 26. The air stream that has entered the upper duct 25 is heated by the catalyst heater 73 and the upper heater 40, and is then, in the form of a hot air stream, blown out through the upper blowout port 30. The air stream that has entered the side duct 26 is heated by the catalyst heater and the upper heater 41, and is then, in the form of a hot air stream, blown out through the side blowout port 31.
The heat generated by the catalyst heater 73 and the upper heater 40 heats the catalyst block 70. The catalyst block 70 is heated, by the radiant heat received from the upstream and downstream sides thereof and the heat carried by the hot air stream passing therethrough, to a temperature (310° C. to 600° C.) at which the catalyst functions satisfactorily. The catalyst paint 74 also is heated, by the radiant heat from the catalyst heater 73 and the upper heater 40 and the heat carried by the hot air stream passing through the inside of the upper duct 25, to a temperature (200° C. to 400° C.) at which the catalyst functions satisfactorily. Likewise, inside the side duct 26, the catalyst block and the catalyst paint are heated.
The hot air stream blown into the cooking chamber 11 heats foods 60. As foods 60 are heated, it releases oily fumes and odor substances. The oily fumes and odor substances, mixed with the hot air stream, are sucked through the suction port 32 into the blower 20, and is then sent out into the upper duct 25 and the side duct 26.
The oily fumes and odor substances that have entered the upper duct 25 are, as they pass through the catalyst block 70, decomposed into carbon dioxide and water. The oily fumes and odor substances that have passed through the catalyst block 70 without being decomposed and those that have passed through the gap between the catalyst block 70 and the interior wall surfaces of the upper duct 25 flows further through the upper duct 25 toward the upper blowout port 30, and meanwhile make contact with the catalyst paint 74 so as to be decomposed. Likewise, the oily fumes and odor substances that have entered the side duct 26 are decomposed by the catalyst block and the catalyst paint.
Accordingly, the hot air streams that blow out from the upper and side blowout ports 30 and 31 contain greatly reduced amounts of oily fumes and odor substances, and are thus less likely to stain foods 60 or spoil the flavor thereof. Also less soiled are the cooking chamber 11 and the blower 20.
Now, different embodiments of the cooking oven 1 described above will be described. A second to an eleventh embodiment, which will be described below, are all characterized by the shape or structure of the fitting member for the catalyst block 70, or how it is fitted. The following descriptions assume that the second to eleventh embodiments are applied to the fitting member 80 used in the upper duct 25, but it should be understood that they are applicable also to the fitting member used in the side duct 26 except in cases where spatial positional relationship matters.
As described earlier, the fitting member 80 is made of a metal having a high thermal conductivity. Moreover, the frame portion 81 is kept in surface contact with the top, left-side, and right-side surfaces of the catalyst block 70. Thus, as shown in
The fitting member 80 also receives infrared radiation from the catalyst heater 73 and the upper heater 40. From the perspective of efficient heating of the catalyst block 70, it is desirable that the fitting member 80 readily absorb radiant heat, i.e., infrared radiation. To this end, the fitting member 80 is used in a form deprived of its inherent metallic luster.
Specifically, as the metal material of which the fitting member 80 is made is selected one whose reflectivity lessens or whose color darkens when a certain amount of heat is applied thereto. The color of the fitting member 80 may be changed by application of heat in the process of its being formed, or may be changed as a result of the fitting member 80 being heated as the cooking oven 1 is used.
An example of such a metal material is stainless steel SUS304 (a code indicating a particular type of stainless steel according to the Japanese Industrial Standards). This type of steel, as the catalyst block 70 is heated to a temperature (310° C. to 600° C.) at which the catalyst functions satisfactorily, loses the luster inherent in stainless steel and comes to have a different color. It even then maintains resistance to corrosion. Thus, this material is suitable for the purpose of the invention.
The infrared absorption coefficient of the fitting member 80 may be further increased by some means. In a fifth embodiment shown in
In the sixth embodiment, the heat-shielding portion 90 is realized with projections 91 formed on the anchoring support portions 82. The projections 91 can be formed by drawing. The contact achieved between the projections 91 and the interior wall surface of the upper duct 25 helps reduce the contact area between the fitting member 80 and the interior wall surface of the upper duct 25. This limits the conduction of heat from the fitting member 80 to the walls of the upper duct 25, and thus more of the heat received by the fitting member 80 conducts to the catalyst block 70.
The projections 91 may be formed not on the anchoring support portions 82 but on the upper duct 25. Alternatively, projections 91 may be formed both on the anchoring support portions 82 and on the upper duct 25 so that they are brought into contact with each other.
Instead of the through holes 92, cuts may be formed in the edges of the frame portion 81 to serve as the heat-shielding portion 90.
The lid 101 is formed out of sheet metal, and has a bent portion 102 formed along the edges thereof. The rim of the bent portion 102 makes contact with the upper duct 25, and thus the area over which the bent portion 102 makes contact with the upper duct 25 is small. That is, the bent portion 102 forms a small-area contact portion interposed between the fitting member 80 and the upper duct 25, and thus serves as the heat-shielding portion 90.
Selecting synthetic resin as the material of the heat-shielding member 103 makes it easy to form it into a shape that runs along the contour of the lid 101. Moreover, it is possible to exploit the elasticity of the synthetic resin to keep airtightness between the upper duct 25 and the lid 101.
The embodiments starting with the eighth shown in
An irregular surface 75 can be formed by forming a large number of dimples on an interior wall surface of a duct or by bonding thereto a sheet having punched holes or laths formed thereon.
The corrugate plate 76 is made of metal, and has catalyst paint applied on both sides thereof. Catalyst paint is applied also to the part of an interior wall surface of the upper duct 25 located on the downstream side of the catalyst block 70, and the corrugate plate 76, having the catalyst paint already applied thereto, is fixed to that interior wall surface as by being fastened with screws.
In this construction, the catalyst paint surface has an increased area. Moreover, since the ridges 76a or grooves 76b run along the air stream, they do not diminish the flow speed of the air stream. This makes it possible to send the hot air stream efficiently while keeping it in contact with the catalyst paint. The side duct 26 is given a similar structure.
Also in this construction, the catalyst paint surface has an increased area. Moreover, since the parallel fins 77a and the grooves 77b between them run along the air stream, they do not diminish the flow speed of the air stream. This makes it possible to send the hot air stream efficiently while keeping it in contact with the catalyst paint. The side duct 26 is given a similar structure.
Also in this construction, the catalyst paint surface has an increased area. Moreover, since the air stream is surely kept in contact with the air-stream-regulating plate 78, the catalyst paint 74 surely functions satisfactorily. The side duct 26 is given a similar structure.
When the fan 22 sucks in air out of the cooking chamber 11, fine particles of oil released from foods 60, together with the air, enters the fan casing 21. Most of the oil that has entered is then sent, together with the air, into the upper duct 25 or the side duct 26, and is decomposed by the catalyst. However, part of the oil, while passing through the fan casing 21, settles on the interior wall surfaces thereof. As time passes, more and more oil settles on the interior wall surfaces of the fan casing 21 until the oil, in the form of oil drips, starts to flow down the wall surfaces. This oil flows through an oil drain hole 21b into the cooking chamber 11. On an occasion of cleaning, the oil is wiped off along with the oil that has settled on the interior surfaces of the cooking chamber 11.
Air flows through the inside of the upper duct 25 and of the side duct 26. Suppose that there is a grid across a cross-section of the duct, and compare the amounts of air stream that flow through the individual squares of the grid. Then, the amounts of air stream that flow through different squares are not equal, but larger amounts of air stream pass through some squares than through others.
When the duct is curved or bent, the air flowing therethrough is acted upon by centrifugal force. This causes an increasingly large amount of air, and thus an increasingly large amount of air stream, to flow through an increasingly outward part of the curve or bend. This tendency persists even after the air has exited from the curve or bend and entered a straight path, and accordingly an increasingly large amount of air stream flows through the part of the straight path that is contiguous with an increasingly outward part of the curve or bend.
According to the present invention, from this perspective, the arrangement of the heaters and the catalyst blocks is ingeniously worked out.
First, a description will be given of the heaters. The upper heater 40 and the side heater 41 are each a sheath heater, and are arranged so as to describe a complicatedly bent shape across a cross-section of the upper duct 25 and the side duct 26, respectively. The main portions of those sheath heaters, i.e., those portions thereof where they generate a large amount of heat, are laid in a ceiling-side portion inside the upper duct 25 (see
As shown in
With respect to the side duct 26, as shown in
The catalyst block 70 is arranged lopsided toward that side of a cross section of the duct at which a larger amount of heat is generated. Specifically, in the upper duct 25, the catalyst block 70 is fitted to the ceiling wall thereof, and, in the side duct 26, the catalyst block 70 is fitted to the left-hand interior side wall thereof as seen from the front.
The fitting member 80 having the catalyst block 70 held therein is fastened, in the upper duct 25, to the ceiling wall thereof with screws and, in the side duct 26, to the left-hand interior side wall thereof, as seen from the front, with screws.
In this way, the catalyst block 70 is fitted to that one of the duct interior walls (of which the ceiling wall is one) which is located where the upper heater 40 or side heater 41 generates a larger amount of heat. As a result, as well as with directly radiated heat, with the heat conducted through the duct walls, the catalyst block is heated efficiently.
Through the side duct 26 flow oily fumes containing oil, fat, odor substances, and the like released from foods 60. Some kinds of food 60 release a large amount of oily fumes. When an extremely large amount of oily fumes is released, the oil that has not been decomposed by the catalyst soils the interior surfaces of the side duct 26, and collects at the bottom thereof. Also as the cooking oven 1 is used for a long period, oil gradually collects.
To overcome these inconveniences, the floor surface 26a of the side duct 26 is so slanted as to sink toward the cooking chamber 11. In the left inner wall 15 of the cooking chamber 11, a plurality of oil drain holes 110 that lead to the lowest part of the floor surface 26 are formed at predetermined intervals along the depth direction of the side duct 26.
In this construction, oil that has flown down to the bottom of the side duct 26 flows along the slanted floor surface 26a, and then flows through the oil drain holes 110 into the cooking chamber 11. The oil that has flown into the cooking chamber 11 can be easily wiped off and thereby disposed of. This prevents oil from remaining on the catalyst paint surface inside the side duct 26, and thus helps maintain the effect of the catalyst paint without deterioration.
In this construction, oil that has flown down to the bottom of the side duct 26 flows along the slanted floor surface 113 of the drain pan 112, and then flows through the oil drain holes 110 into the cooking chamber 11. The oil that has flown into the cooking chamber 11 can be easily wiped off and thereby disposed of. This prevents oil from remaining on the catalyst paint surface inside the side duct 26, and thus helps maintain the effect of the catalyst paint without deterioration.
When the drain pan 112 becomes soiled, it is drawn out by pulling a knob 114 fitted to the front face thereof. The drain pan 112 is cleaned with detergent or the like, and is then put back into the bottom of the side duct 26.
Advisably, the interior shape of the side duct 26 and the shape of the catalyst paint surface are so devised as to permit easy collection of oil in the drain pan 112. This applies also to the nineteenth embodiment.
A mechanism for oil disposal as described above may be provided also for the upper duct 25. To permit oil to flow into the cooking chamber 11, the floor surface of the upper duct 25 is slanted as follows. It is so slanted as to one-sidedly sink toward one of the rear inner wall 14, left inner wall 15, and right inner wall 16; alternatively, like a gable roof, it is so slanted as to two-sidedly sink toward both the left inner wall 15 and right inner wall 16; or alternatively, like a hipped roof, it is so slanted as to three-sidedly sink toward the rear inner wall 14, left inner wall 15, and right inner wall 16. In any case, oil drain holes are formed as close as possible to the rear inner wall 14, left inner wall 15, and right inner wall 16 so that oil does not drip onto foods 60. Consideration needs to be taken also to prevent entry of oil into the blower 20.
A drain pan like the drain pan 112 used in the nineteenth and twentieth embodiments may be provided for the upper duct 25.
In a case where a drain pan is provided for the upper duct 25 or side duct 26, the position in which to arrange the drain pan, the shape and fitting arrangement of the door 17 should advisably be so designed that the drain pan can be drawn out when the door 17 is open.
The embodiments described hereinbefore all deal with cases in which catalyst paint is applied to an interior wall surface of a duct through which a hot air stream for heating foods is passed, i.e., a duct that forms a principal circulation passage. It is, however, also possible to provide a subsidiary circulation passage through which the air inside a cooking chamber is circulated for the purpose of decomposing oil fumes and odor substances rather than for the purpose of heating foods, and apply catalyst paint to an interior wall surface of a duct that forms the subsidiary circulation path.
A catalyst block does not necessarily have to be used in combination with catalyst paint. That is, it is also possible to rely solely on catalyst paint.
It should be understood that the embodiments of the present invention described hereinbefore are merely examples of constructions according to the invention, and are not meant to limit the scope of the invention in any way; that is, many further modifications and variations are possible in carrying out the invention within the concept of the invention.
As described above, according to the present invention, in a cooking oven wherein a catalyst is made to act upon a hot air stream circulated inside a cooking chamber in order to decompose oily fumes and odor substances, it is possible to efficiently heat the catalyst to make it function satisfactorily. Moreover, it is possible to arrange the catalyst easily. Furthermore, in arranging a heater inside a duct through which a air stream is sent to the cooking chamber, it is possible to improve the air heating efficiency of the heater. With these features, it is possible to enhance the cooking performance of professional-use and household-use cooking ovens.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2001-400835 | Dec 2001 | JP | national |
| 2001-400877 | Dec 2001 | JP | national |
| 2002-107003 | Apr 2002 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP02/13460 | 12/24/2002 | WO | 00 | 10/18/2004 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO03/058125 | 7/17/2003 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3823760 | Bloomfield et al. | Jul 1974 | A |
| 3889099 | Nuss | Jun 1975 | A |
| 4110916 | Bemrose | Sep 1978 | A |
| 4244979 | Roderick | Jan 1981 | A |
| 4503760 | Pryputsch et al. | Mar 1985 | A |
| 4823766 | Violi | Apr 1989 | A |
| 4824644 | Cox et al. | Apr 1989 | A |
| 5029519 | Boyen | Jul 1991 | A |
| 5160829 | Chang | Nov 1992 | A |
| 5272963 | Del Fabbro | Dec 1993 | A |
| 5423248 | Smith et al. | Jun 1995 | A |
| 5481962 | Tedesco | Jan 1996 | A |
| 6070517 | Helm | Jun 2000 | A |
| Number | Date | Country |
|---|---|---|
| 1257571 | Jun 2000 | CN |
| 57-155039 | Sep 1982 | JP |
| 58-104803 | Jul 1983 | JP |
| 62-141115 | Sep 1987 | JP |
| 62-268921 | Nov 1987 | JP |
| 3-199822 | Aug 1991 | JP |
| 4-169716 | Jun 1992 | JP |
| 5-90204 | Dec 1993 | JP |
| 6-323553 | Nov 1994 | JP |
| 7-42946 | Feb 1995 | JP |
| 7-151333 | Jun 1995 | JP |
| 8-66460 | Mar 1996 | JP |
| 10-202112 | Aug 1998 | JP |
| 2000-220858 | Aug 2000 | JP |
| 2000-510568 | Aug 2000 | JP |
| 2001-321291 | Oct 2001 | JP |
| 9854517 | Dec 1998 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20050039613 A1 | Feb 2005 | US |
