Information
-
Patent Grant
-
6541745
-
Patent Number
6,541,745
-
Date Filed
Friday, November 9, 200122 years ago
-
Date Issued
Tuesday, April 1, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Birch, Stewart, Kolasch & Birch, LLP
-
CPC
-
US Classifications
Field of Search
US
- 219 681
- 219 685
- 219 757
- 219 400
- 126 21 A
- 126 273 A
- 126 275 E
-
International Classifications
-
Abstract
In a heater system for a microwave oven including an air tunnel having an suction portion and a discharge portion, formed at an upper surface of a cooking chamber, a fan assembly installed inside the air tunnel and having a circulation fan forming air flow by sucking air inside the cooking chamber through the suction portion and discharge the sucked air through the air tunnel and the discharge portion, a first heater chamber having a first heater installed inside the air tunnel and heating air discharged into the discharge portion from the air tunnel, and a second heater chamber having a second heater installed inside the air tunnel and emitting radiation heat into the cooking chamber, wherein the suction portion and the discharge portion are formed near opposite side walls of the cooking chamber.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a microwave oven, and in particular to a heater system for a microwave oven which is capable of transferring heat from a heater to cooking object more efficiently.
2. Description of the Related Art
A microwave oven heats cooking object by using microwave energy. Recently, in order to add various heating functions to a microwave oven, a heater is installed as another heating source besides microwave energy and heat generated by the heater is used for heating cooking object.
FIG. 1
is a sectional view illustrating construction of a heater system for a microwave oven in accordance with a prior art.
As depicted in
FIG. 1
, in the heater system for the microwave oven in accordance with the prior art, a cooking chamber
2
is formed inside a cavity in order to cook cooking object F placed on a tray
2
′.
An additional heater chamber
5
is formed at the upper portion of an upper plate
3
forming a ceiling of the cooking chamber
2
, and heaters
7
,
7
′ for heating the cooking object F on the tray
2
′ are installed inside the heater chamber
5
.
And, a circulation fan
9
is installed at the center portion of the heater chamber
5
, and is rotated by a circulation motor
10
on the upper portion of the heater chamber
5
.
And, a suction portion
3
S and a discharge portion
3
E for air circulation generated by the circulation fan
9
are respectively formed on the upper plate
3
corresponded to the bottom surface of the heater chamber
5
.
Herein, the suction potion
3
S is formed at a position corresponded to the circulation fan
9
, and the discharge portion
3
E is formed at a position corresponded to the heaters
7
,
7
′. The suction portion
3
S and the discharge portion
3
E are formed as a plurality of air passage holes.
In the heater system for the microwave oven in accordance with the prior art, in order to perform heating with the heaters
7
,
7
′, power is applied to the heaters
7
,
7
′, heat is generated, and at the same time the circulation fan
9
is operated.
By the rotation of the circulation fan
9
, air inside the cooking chamber
2
is sucked into the heater chamber
5
through the suction portion
3
S, the sucked air is heated while passing through the heaters
7
,
7
′ in the heater chamber
5
and is discharged into the cooking chamber
2
through the discharge portion
3
E.
The heated air discharged into the cooking chamber
3
heats the cooking object F and is again sucked into the heater chamber
5
through the suction portion
3
S.
However, there are problems, which will be described in the following, in the heater system for the microwave oven in accordance with the prior art.
First, air flow inside the cooking chamber
2
is formed at the suction portion
3
S at a center of the upper plate and the discharge portion
3
E at the circumference on the basis of the ceiling of the cooking chamber
2
formed by the upper plate
3
, and such air flow does not circulate the whole cooking chamber
2
uniformly.
In more detail, air flow is well-performed mostly at the upper center portion of the cooking chamber
2
adjacent to the circulation fan
9
, air flow is not well-performed at the lower portion of the cooking chamber
2
, especially at the corner portion of the cooking chamber
2
, and accordingly air discharged through the discharge portion
3
E is directly sucked into the suction portion
3
S as shown with arrows in FIG.
1
.
Accordingly, heat transfer inside the cooking chamber
2
is not uniform and the uniform heating of the cooking object F can not be performed.
In addition, air flowing into the heater chamber
5
by the circulation fan
9
is heated by passing through the heaters
7
,
7
′, passes the discharge portion
3
E formed at the upper plate
3
and is discharged into the cooking chamber
2
, herein lots of heat loss is occurred by transferring large amount of heat to the upper plate
3
. In more detail, heat to be transferred to the cooking object F is transferred to the upper plate
3
first, accordingly heat loss occurs.
In the meantime, the air convection by the circulation fan
9
is performed by connecting the cooking chamber
2
and the heater chamber
5
, for the convection of air, the discharge portion
3
E is formed at the upper plate
3
corresponded to the heaters
7
,
7
′. However, impurities such as pieces of cooking object or fat, etc. in the cooking object
2
can be conveyed to the heaters
7
,
7
′ through the discharge portion
3
E. Particularly, because the impurities in the cooking chamber
2
can spit to the upper portion of the cooking chamber
2
, the heaters
7
,
7
′ can be easily contaminated.
SUMMARY OF THE INVENTION
Accordingly, in order to solve the above-mentioned problems, it is an object of the present invention to provide a heater system for a microwave oven which is capable of heating cooking object uniformly by improving convection of heat generated by heater.
It is another object of the present invention to provide a heater system for a microwave oven which is capable of transferring heat generated by heater to cooking object more efficiently.
It is yet another object of the present invention to provide a heater system for a microwave oven which is capable of improving operation reliability of a heater mostly using a radiation heat.
In order to achieve the above-mentioned objects, a heater system for a microwave oven in accordance with the present invention includes a cooking chamber having an upper surface and side walls; an air tunnel having a suction portion and a discharge portion, said air tunnel formed at the upper surface of the cooking chamber; a fan assembly installed inside the air tunnel, said fan assembly having a circulation fan forming air flow by sucking air inside the cooking chamber through the suction portion and discharging the sucked air through the discharge portion by passing the air tunnel; a first heater chamber having a first heater installed inside the air tunnel and heating air discharged through the discharge portion; and a second heater chamber having a second heater installed inside the air tunnel and emitting radiation heat into the cooking chamber, wherein the suction portion and the discharge portion are formed near opposite side walls of the cooking chamber.
In addition, the first heater chamber is installed directly at an upper portion of the discharge portion, is divided from the air tunnel by a first reflection plate having a plurality of connection holes, and is opened so as to be directly connected to the cooking chamber.
The second heater chamber is positioned between the suction portion and the discharge portion and is defined formed by a second reflecting plate. And it is preferable to install the second heater chamber between the suction portion and the discharge portion.
The second heater chamber is divided from the cooking chamber by a filter capable of permeating a radiation heat into the cooking chamber.
In the heater system for the microwave oven in accordance with the present invention, the air flow inside the cooking chamber by the circulation fan can be formed more uniformly, accordingly the heat can be transferred to cooking object more efficiently.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1
is a sectional view illustrating a heater system for a microwave oven in accordance with a prior art;
FIG. 2
is a sectional view illustrating a construction of a heater system for a microwave oven in accordance with the present invention; and
FIG. 3
is a sectional view illustrating operation state by a heater of a heater system for a microwave oven in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A heater system for a microwave oven in accordance with the present invention will be described in detail with reference to accompanying drawings.
FIG. 2
is a sectional view illustrating a construction of a heater system for a microwave oven in accordance with the present invention.
As depicted in
FIG. 2
, a cooking chamber
22
is formed inside a cavity
20
of a microwave oven. In the cooking chamber
22
, a cooking object F on a tray
22
′ is cooked by microwave energy supplied by a magnetron (not shown) installed at an electric room(not shown), or by heat generated by a heater system.
An upper plate
24
is formed at the upper surface of the cooking chamber
22
and, at the same time forms a ceiling of the cooking chamber
22
, a suction portion
26
forming air flow from the inside of the cooking chamber
22
and a discharge portion
28
forming air flow from the outside of the cooking chamber
22
are respectively formed at the upper plate
24
.
Herein, the suction portion
26
is formed in the upper plate
24
at one side of the cooking chamber
22
, and the discharge portion
28
is formed in the upper plate
24
at another side of the cooking chamber
22
opposite to the suction portion
26
.
The discharge portion
28
is formed to have a certain area for directly connecting a space in which a first heater
40
, namely a first heater chamber
40
′ with the cooking chamber
22
.
And, in order to make air flow smoother, an auxiliary discharge portion
28
′ is formed around the discharge portion
28
in the upper plate
24
.
Herein, it is preferable to place the suction portion
26
around one outer end of the tray
22
′ and the discharge portion
28
around another end of the tray
22
′ opposite to the one outer end.
In the meantime, an air tunnel
30
is formed on the upper plate
24
. A circulation fan
34
is installed inside the air tunnel
30
, it is preferable to install the circulation fan
34
near to the suction portion
26
, as depicted in
FIG. 2
, it is most preferable to install the circulation fan
34
directly at upper position of the suction portion
26
.
The air inside the cooking chamber
22
is sucked into the air tunnel
30
through the suction portion
26
by the circulation fan
34
, the sucked air is discharged into the cooking chamber
22
by passing through the air tunnel
30
, a first heater chamber
40
′ and the discharge portion
28
of the air tunnel
30
. A circulation motor
32
installed at the upper portion of the air tunnel
30
operates the circulation fan
34
.
The first heater
40
transferring heat to cooking object F by convection is installed at the upper portion of the discharge portion
28
formed at the opposite position of the suction portion
26
. Particularly, the first heater chamber
40
′ is formed inside the air tunnel
30
, defined by a first reflecting plate
42
having a plurality of connection holes
44
at the upper position of the discharge portion
28
, and the heat transfer inside the cooking chamber
22
can be performed efficiently by installing the first heater
40
inside the heater chamber
40
′.
The air passed through the air tunnel
30
flows through the plurality of connection holes
44
formed at the first reflecting plate
42
into the cooking chamber
22
. Herein, a ceramic heater can be used as the first heater
40
.
And, a second heater
50
emitting radiation heat into cooking object F is installed between the suction portion
26
and the discharge portion
28
. As depicted in
FIG. 2
, the second heater
50
is installed inside a second heater chamber
50
′. In more detail, the second heater chamber
50
′ is defined by the upper plate
24
and the second reflecting plate
52
.
And a plurality of holes
53
are formed in the second reflecting plate
52
, though which the air sucked into the air tunnel from the inside of the cooking chamber
22
flows. With the airflow through the plurality of holes
53
formed in the second reflecting plate can cool the second reflecting plate
52
and the second heater.
An opened portion
29
is formed at the upper plate
24
and defines the second heater chamber
50
′ together with the second reflecting plate
52
, accordingly the second heater
50
emits radiation heat to the cooking chamber
22
through the opened portion
29
.
In the meantime, such as a glass filter
54
is installed at the opened portion
29
in order to prevent penetration of impurities from the cooking chamber
22
, accordingly contamination of the second heater
50
can be prevented and radiation heat can be easily transferred. It is preferable to use such as a halogen lamp as the second heater
50
.
The operation of the heater system for the microwave oven in accordance with the present invention will be described.
FIG. 3
is a sectional view illustrating operation state of a heater of a heater system for a microwave oven in accordance with the present invention.
When the heater system using the heaters
40
,
50
starts to operate, the first heater
40
and the second heater
50
generate heat, and the circulation fan
34
is operated by the circulation motor
32
.
When the circulation fan
34
operates, as depicted in
FIG. 3
, the air inside the cooking chamber
22
is sucked into the air tunnel
30
through the suction portion
26
. The air sucked into the air tunnel
30
flows toward the first reflecting plate
42
covering the first heater
40
by passing through the upper portion of the second reflecting plate
52
covering the second heater
50
.
The air flows toward the first heater
40
through the connection hole
44
formed at the first reflecting plate
42
covering the first heater
40
, the air heated in the first heater
40
flows into the side of the cooking chamber
22
through the discharge portion
28
.
The air flowing into the cooking chamber
22
heats cooking object F by flowing into the cooking chamber
22
by the air flow formed by the circulation fan
34
and flows again into the air tunnel
30
through the suction portion
26
. Herein, the auxiliary discharge portion
28
′ performs a function for forming air flow together with the whole connection holes
44
formed at the first reflecting plate
42
.
Herein, because the discharge portion
28
is formed as not a plurality of holes but one hole having a certain area, the air flow passing the first heater
40
can flow into the cooking chamber
22
more smoothly, and the heat transferred from the first heater
40
can be wholly transferred to cooking object F with small heat loss transferred to the upper plate
24
.
In the meantime, the heat generated in the second heater
50
is transferred to cooking object F as a radiation heat (shown as arrows in
FIG. 3
) transferring through the glass filter
54
installed at the opened portion
29
into the cooking chamber
22
and heats cooking object F.
Herein, only the radiation heat radiating through the glass filter
54
can be transferred to cooking object F and the radiation heat is not affected by the internal circumstances. Accordingly, the second heater
50
is not contaminated by impurities from the cooking chamber
22
.
And, because the second reflecting plate
52
covering the second heater
50
is installed inside the air tunnel
30
, the second reflecting plate
52
can be cooled by the air flow formed by the circulation fan
34
, and it is possible to prevent excessive temperature rising of the second reflecting plate
52
although the output of the second heater
50
is relatively high and, at the same time the air cooling the second reflecting plate
52
is heated by the second reflecting plate
52
.
Additionally, all elements of the heater system can be installed in one heater chamber.
As described above, in the heater system for the microwave oven in accordance with the present invention, by forming the air flow uniformly inside the cooking chamber, it is possible to heat cooking object uniformly without installing an additional heater at the lower portion of the cooking chamber, and particularly, heat can be transferred uniformly to the cooking object with smaller heat loss in the heat transferring process by the convection and radiation of the heater system installed at the upper portion of the cooking chamber.
And, by constructing the heater supplying the radiation heat so as to be divided from the internal circumstances of the cooking chamber, it is possible to prevent the heater from being contaminated by impurities from the cooking chamber, and because the reflecting plate of the heater can be efficiently cooled by the air flow formed by the circulation fan, the cooking can be performed quickly by adjusting the output of the heater relatively high.
Claims
- 1. A heater system for a microwave oven, comprising:a cooking chamber having an upper surface and side walls; an air tunnel having a suction portion and a discharge portion, said air tunnel formed at the upper surface of the cooking chamber; a fan assembly installed inside the air tunnel, said fan assembly having a circulation fan forming air flow by sucking air inside the cooking chamber through the suction portion and discharging the sucked air through the discharge portion by passing the air tunnel; a first heater chamber having a first heater installed inside the air tunnel and heating air discharged through the discharge portion; and a second heater chamber having a second heater installed inside the air tunnel and emitting radiation heat into the cooking chamber, wherein the suction portion and the discharge portion are formed near opposite side walls of the cooking chamber.
- 2. The system of claim 1, wherein the first heater chamber is installed directly at an upper portion of the discharge portion, is divided from the air tunnel by a first reflection plate having a plurality of connection holes, and is opened so as to be directly connected to the cooking chamber.
- 3. The system of claim 1, wherein the second heater chamber is positioned between the suction portion and the discharge portion and is defined formed by a second reflecting plate.
- 4. The system of claim 3, wherein the second heater chamber is divided from the cooking chamber by a filter capable of permeating a radiation heat into the cooking chamber.
- 5. The system of claim 4, wherein the filter is a glass filter.
- 6. The system of claim 1, wherein the second heater chamber is divided from the cooking chamber by a filter capable of permeating a radiation heat into the cooking chamber.
- 7. The system of claim 1, wherein the circulation fan of the fan assembly is positioned directly at an upper portion of the suction portion in the air tunnel.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000/0066850 |
Nov 2000 |
KR |
|
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4481396 |
Matsubayashi et al. |
Nov 1984 |
A |
6005235 |
Shin |
Dec 1999 |
A |
6093918 |
Sohn |
Jul 2000 |
A |
Foreign Referenced Citations (1)
Number |
Date |
Country |
5-52352 |
Mar 1993 |
JP |