Electric heating – Microwave heating – With diverse-type heating
Reexamination Certificate
2000-06-28
2001-10-02
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
With diverse-type heating
C219S681000, C219S746000, C219S756000, C219S757000
Reexamination Certificate
active
06297485
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a microwave oven, and in particular to a microwave oven which is capable of convection cooking and grill cooking by including an apparatus generating radiant heat and convection-performing the radiant heat inside of a cavity.
2. Description of the Prior Art
A microwave oven cooks foodstuff by utilizing molecular motion of the foodstuff which is generated by microwave.
The conventional microwave oven will now be described.
As depicted in
FIG. 1
, a door
15
having a transparent door screen
14
is installed on the front of the mainframe as hinged gate, a control panel
16
for setting functions and cooking time is installed on the side of the door
15
.
The conventional microwave oven having convection cooking function will now be described.
As depicted in
FIG. 2
, there is a cooking cavity
2
a
having a certain area for cooking inside of the mainframe
1
a
, a magnetron
3
is installed on the outer side of the cavity
2
a
, a waveguide
17
is formed at the side of the magnetron
3
for guiding microwave inside of the cavity
2
a.
A turntable
9
is placed on the inner bottom surface of the cavity
2
a
to be mounted on the food stuff, a motor shaft
8
is connected to the center portion of the bottom surface of the turntable
9
, the motor shaft is extended outwardly and connected to a turntable operation motor
7
.
A heater
18
covered by a heater chamber
19
generating heat for convection cooking is placed at the outer side of the cavity
2
a
, a blast fan
23
placed at the side of the heat chamber
19
for circulating the heat generated by the heater
18
inside of the cavity
2
a
is connected to a operating motor
20
, a convection cooking table
24
is installed at the center portion of the cavity
2
a
so as to be removable.
Herein, a plurality of vent holes
22
are formed at the wall surface of the cavity
2
a
where the heater
18
is installed in order to circulate the heat of the heater
18
inside of the cavity
2
a.
The convection microwave oven is mainly used to cook bread, in the cooking process, the bread is placed on the convection cooking table
24
, the heater
18
and blast fan
23
operate to generate heat from the heater
18
and circulate the heat inside of the cavity
2
a
, and keep temperature inside of the cavity
2
a
uniformly while the bread is cooked.
The conventional grill cooking microwave oven will now be described. As depicted in
FIG. 3
, a cavity
2
a
having a certain area is formed inside of a mainframe
1
a
for cooking foodstuff, a magnetron
3
is installed at the outer side of the cavity
2
a
for generating microwave, a waveguide
17
is formed at the side of the magnetron for guiding microwave inside of the cavity
2
a.
A turntable
9
is placed on the inner bottom surface of the cavity
2
a
to be mounted on the foodstuff, a motor shaft
8
is connected to the center bottom portion of the turntable
9
, the motor shaft
8
is extended outwardly and connected to a turntable operation motor
7
.
A heater
25
supported by a heater holder
24
is installed at the outer upper portion of the cavity
2
a
, a reflector
26
is installed at the outer upper portion of the cavity
2
a
adjacent to the heater
25
for reflecting the heat generated by the heater
25
inside of the cavity
2
a.
The grill cooking microwave oven is mainly used to cook meat, in the cooking process, the meat is placed on the turntable
9
, the heater operates to generate heat, the heat generated by the heater
25
and the reflected heat by the reflector
26
are transmitted inside of the cavity
2
a.
However, in the above-mentioned convection cooking microwave oven, controlling the temperature inside of the cavity is difficult due to non-uniformity of heat distribution, because of the distance between the heater
18
and the foodstuff, portions adjacent to the heater
18
has high temperature, the opposite wall portion from the heater
18
has low temperature. In order to uniform the heat distribution, the blast fan
23
is installed at the side of the heater, but the circulated air flow interferes with the heat flow generated by the heater
18
, accordingly the heat can not be transmitted properly to the opposite wall inside of the cavity
2
a.
In addition, the conventional grill cooking microwave oven, non-uniformity of the heat distribution may occur because of the distance between the heater and the foodstuff, and it requires long time to get enough temperature inside of the cavity because it only uses convection heat transfer having limited 600° C. surface temperature.
Furthermore, both heating apparatus are separately required for each convection cooking and grill cooking in the conventional microwave oven.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a microwave oven which is capable of convection cooking and grill cooking, and efficient and speed cooking by uniformity of heat distribution inside of a cavity.
To achieve the objects, there is provided a microwave oven comprising a cavity having a certain area for cooking, a magnetron installed outside of the cavity for generating microwave, a waveguide installed on the side of the magnetron and its end extended inside of the cavity for transmitting microwave inside of the cavity.
The waveguide includes a bidirectional flow channel for transmitting microwave selectively inside of the cavity in accordance with cooking function. A microwave guide plate is installed inside of the waveguide so as to be rotational for guiding the microwave to selected direction between the two direction of the flow channel. A plasma lamp is installed adjacent to the side of the flow channel in order to generate radiant heat by being heated by the microwave.
In the present invention, it is advisable for a blast pan to be installed at the side of the plasma lamp in order to circulate high temperature heat generated by the plasma lamp inside of the cavity.
It is advisable for the outer surface of the plasma lamp to be coated with far infrared ray in order to make the reflected light from the plasma into far infrared radiation condition.
REFERENCES:
patent: 3783220 (1974-01-01), Tanizaki
patent: 4042850 (1977-08-01), Ury et al.
patent: 5420390 (1995-05-01), Abe
patent: 1-200590 (1989-08-01), None
patent: 3-129696 (1991-06-01), None
Kim Yang Kyeong
Ryu Jong Gwan
Leung Philip H.
LG Electronics Inc.
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