Electric heating – Microwave heating – Enclosed cavity structure
Reexamination Certificate
2000-06-30
2001-03-13
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
Enclosed cavity structure
C219S758000, C126S02100R, C362S092000
Reexamination Certificate
active
06201225
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multi-purpose microwave oven, and more particularly, to an air duct in a multi-purpose microwave oven in which an oven lamp is provided in an air duct and cooled by flow air passing through the air duct so as not to be overheated by self-heat and external heat.
2. Discussion of the Related Art
Generally, a microwave oven is a cooking machine which cooks food by friction heat between molecules as arrangement of molecules is deranged using high frequency of about 2,450 MHz as a heat source. Particularly, a multi-purpose microwave oven has a convection function and a combination function as well as a microwave function. The convection function is performed in such a manner that food is cooked at hot air by heat of a heater. The combination function combines the microwave function with the convection function.
The multi-purpose microwave oven will be described with reference to
FIGS. 1 and 2
.
As shown in
FIGS. 1 and 2
, the multi-purpose microwave oven includes a main body
1
, a base plate
2
on which the main body
1
is mounted, a U-bended outer case
3
which covers an upper part and both sides of the main body
1
, a door
4
and a control panel
5
. The door
4
and the control panel
5
are mounted at the front of the main body
1
.
A cooking chamber
10
is provided at one side inside the main body
1
, and a component chamber
11
is provided at the other side inside the main body
1
. Various components required to drive the microwave oven are collected in the component chamber
11
.
Furthermore, a tray
12
is provided on the bottom inside the cooking chamber
10
and rotated by a motor (not shown) to evenly heat food put on the tray. A heater
13
is provided on an upper part outside the cooking chamber
10
. The heater
13
emits heat when the convection function is operated so that the heat of the heater
13
flows into the cooking chamber
10
through a porous part
10
a
which is formed on a top surface of the cooking chamber
10
.
Main components such as a transformer
21
and a magnetron
20
which is a high frequency oscillator are provided in the component chamber
21
. The transformer
21
transforms power source for home use to high voltage required to oscillate the magnetron
20
. Furthermore, a cooling pan
22
, a waveguide
23
, and an air duct
24
are provided in the component chamber
21
. The cooling pan
22
includes a pan motor for cooling high heat generated when oscillating the magnetron
20
. The waveguide
23
guides microwave generated by the magnetron to the cooking chamber
10
. The air duct
24
guides air generated by rotative force of the cooling pan to the cooking chamber
10
.
In the aforementioned multi-purpose microwave oven, to heat/cook food, in a state that the cooking chamber
10
is opened by opening the door
4
, cooking food is put on the tray
12
and then the door
4
is closed to seal the cooking chamber
10
.
Subsequently, one of the microwave function, the convection function and the combination function is selected in accordance with food type and food state, so that the microwave oven is operated.
For example, if the microwave function is selected, high frequency of about 2,450 MHz per second is oscillated from the magnetron
20
and propagated into the cooking chamber
10
through the waveguide
23
. The high frequency propagated into the sealed cooking chamber
10
is scattered and reflected on the wall of the cooking chamber
10
to be incident upon the food. Thus, arrangement of molecules of the food is deranged. For this reason, friction heat between the molecules is generated so that the food is heated and cooked.
If the convection function is selected, the heater
13
emits heat and the heat of the heater
13
flows into the cooking chamber
10
through the porous part
10
a.
Thus, the food is heated by the convection. In this case, to preserve a temperature in the cooking chamber, the air duct
24
is closed so as not to flow air generated by the cooling pan
22
from the component chamber
11
into the cooking chamber
10
. To this end, a damper
26
is provided in the air duct
24
and is controlled by a solenoid
25
.
Meanwhile, a porous part
14
a
is formed in a partition
14
which isolates the cooking chamber
10
from the component chamber
11
. An oven lamp
27
is formed at a side of the component chamber
11
next to the porous part
14
a so as to illuminate the cooking chamber
10
through the porous part
14
a.
Particularly, to improve illuminance, the oven lamp
27
is mounted in a stainless lamp box
28
having excellent reflexibility. A heat blocking plate
29
is provided at a side of the lamp box
28
to block cooking heat generated during cooking (see FIG.
2
).
However, as heat emitted from the oven lamp
27
is combined with cooking heat, heat of about 200° C. is actually conducted to the heat blocking plate
29
. As a result, the heat blocking plate
29
has poor heat blocking function. This often shorts the oven lamp
27
, reduces its service life, and incurs the A/S cost.
Furthermore, since the air duct
24
is separated from the oven lamp
27
, the volume of the microwave oven increases and the number of components increases, thereby causing adverse effect in price competition.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to an air duct in a multi-purpose microwave oven that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an air duct in a multi-purpose microwave oven which prevents an oven lamp from being overheated.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the scheme particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, an air duct in a multi-purpose microwave oven according to the present invention includes a main body having an air inlet and an air outlet to communicate a cooking chamber with a component chamber, a partition provided on an inner space of the main body to guide air flow into a first path located at the air inlet and a second path communicated with the cooking chamber, an air discharge opening formed on a wall on the first path to communicate with the outside, an oven lamp provided in the first path, and a closing means provided between the first oath and the second path, for selectively blocking air flow into the second path so that air flown into the main body is selectively discharged through the air outlet or the air discharge opening.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
REFERENCES:
patent: 5847377 (1998-12-01), Yang et al.
patent: 63-189714 (1988-08-01), None
patent: 5-10532 (1993-01-01), None
patent: 6-94243 (1994-04-01), None
Fleshner & Kim LLP
Leung Philip H.
LG Electronics Inc.
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