Electric heating – Microwave heating – With diverse-type heating
Reexamination Certificate
2000-12-28
2003-03-04
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
With diverse-type heating
C219S685000, C219S756000, C219S757000, C219S400000, C219S536000, C126S02100R
Reexamination Certificate
active
06528773
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 improving a cooking quality and cooking time by elevating heat efficiency of a heater.
2. Description of the Prior Art
A microwave oven cooks foodstuff by utilizing molecular motion of the foodstuff by using 2,450 MHz microwave.
FIG. 1
is a perspective view illustrating a microwave oven according to the conventional technology, and
FIG. 2
is a sectional view illustrating a microwave oven according to the conventional technology.
As depicted in FIG.
1
and
FIG. 2
, the microwave oven comprises a main body including a cavity
10
where the foodstuff is cooked, an electric room
12
installed various electric units, and a door
14
installed on the front of the main body for opening/closing the cavity.
The electric room
12
includes a magnetron
16
generating high frequency, and a high voltage transmitter
18
and a high voltage capacitor
20
for applying a high voltage to the magnetron
16
.
In addition, a radiating fan
22
for cooling the electric parts by sucking the outer air and an operating motor (not shown) for operating the radiating fans are installed at the rear side of the electric room
12
.
And, a tray
25
to be mounted on the foodstuff is installed in the cavity
10
, and a transparent window
26
for seeing through the cavity when the door
14
is closed is installed on the door
14
.
A heater
28
for providing heat inside of the cavity
10
in a cooking state and a heater housing
30
for covering the heater
28
are installed between the rear wall of the cavity
10
and a casing
11
.
A plurality of discharge holes
30
a
for discharging the heat of the heater
28
into the cavity
10
and a plurality of suction holes for suctioning the inner air of the cavity
10
which is used for cooking the foodstuff to the heater
28
are formed on the inner rear wall of the cavity
10
.
And, a blast fan
32
for making the air flow so as to circulate through the discharge holes
30
a
and suction holes
30
b
of the cavity, and an operating motor for operating the blast fan
32
are installed on the heater housing
30
.
The operation of the above described conventional microwave oven will now be described.
First, when the blast fan
32
is operated in the cooking state, the inner air of the cavity
10
flows to the heater housing
30
through the suction holes
30
b
by rotary force of the blast fan
32
.
The air flowed to the heater housing
30
is heated through the heater by heat exchange with the heater
28
, and is discharged into the cavity
10
through the plurality of discharge holes
30
a.
The high temperature air discharged into the cavity
10
heats the foodstuff, and flows to the heater housing
30
through the suction holes
30
b
, accordingly the foodstuff can be cooked by repeating above process.
However, the above described conventional microwave oven does not comprise a heat transmission means for transmitting efficiently heat energy generated from the heater
28
, accordingly heat efficiencies of convection energy and radiant energy are lower, therefore the efficiency of the heater
28
is lower and cooking efficiency of the microwave oven is worse.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a heating device of a microwave oven which is capable of increasing heat efficiency of the heater and cooking quality and cooking speed by improving a heat transfer structure of the microwave oven so as to heighten heat transmission efficiency between the heater and air.
To achieve the object, a microwave oven including a cavity having a certain area for cooking of the present invention comprises a flow path formed between a main body and the cavity so as to be connected from a side of the cavity to the upper surface of the cavity, a heater installed on the side of the flow path corresponding to the outer upper surface of the cavity for emitting heat, a discharge hole installed on the upper surface of the cavity corresponding to the lower portion of the heater for discharging the heat of the heater into the cavity, an inlet installed on the lower portion of the side wall of the cavity for making the air inside of the cavity flow to the flow channel, and a circulating fan installed on a certain portion of the flow channel for circulating the air inside of the cavity flowed through the inlet to the heater.
In addition, in the microwave oven of the present invention, there are a plurality of discharge holes installed as concentric circles centering around the discharge hole on the center portion, and it is advisable to form the discharge hole adjacent utmost to the circulating fan so as to be the smallest among the plurality of discharge holes.
In addition, in the conventional microwave oven of the present invention, there are the plurality of discharge holes installed along the width direction of the flow path, and it is advisable to form the discharge hole formed on the center portion so as to be the smallest among the plurality of discharge holes.
In addition, in the conventional microwave oven of the present invention, when the high temperature air circulated by the circulating fan passes through the discharge holes, the maximum discharge speed is maintained as air velocity 9~13 m/s, passage dimension is maintained as 26~38 cm
2
, air volume circulated through the discharge holes is maintained as 1.4~2.0 m
3
/min when heat value is 3 kW, when the heat value is bigger/smaller than 3 kW, the air volume is changed in proportion to the heat value.
In addition, in the microwave oven of the present invention, it is advisable to from a reflecting plate on the external surface of the heater so as to cover the heater in order to provide whole radiant energy emitted from the heater to the cavity.
In addition, in the microwave oven of the present invention, it is advisable to form a plurality of circulation holes on a portion corresponding to the circulating fan in order to pass the circulating air inside of the cavity.
In addition, in the microwave oven of the present invention, it is advisable to form the heater so as to be zigzag-curved, and a heating plate for increasing heating dimension is installed on the heater.
In addition, in the microwave oven of the present invention, it is advisable to install the heater so as to be crossed on the square with the flow direction of the circulating air in order to increase the quantity of heat transmission between the heater and circulating air by always getting a maximum temperature difference between the heater and the circulating air.
In addition, in the microwave oven of the present invention, it is advisable to install the heater so as to be inclined at a certain degree to the flow direction of the circulating air in order to increase the quantity of heat transmission between the heater and circulating air by always getting a maximum temperature difference between the heater and circulating air.
In addition, in the microwave oven of the present invention, it is advisable to form the plurality of heating plates having through holes at the center portion so as to be penetrated and contacted by the heater.
In addition, in the microwave oven of the present invention, it is advisable to form a contact protrusion on the circumference of the through holes of the heating plates in order to increase the contact surface with the heater.
REFERENCES:
patent: 3692968 (1972-09-01), Yasuoka
patent: 3716687 (1973-02-01), Constable
patent: 4137442 (1979-01-01), Tateda
patent: 4154861 (1979-05-01), Smith
patent: 4332992 (1982-06-01), Larsen et al.
patent: 4870255 (1989-09-01), Fujii et al.
patent: 5483044 (1996-01-01), Thorneywork et al.
patent: 6060701 (2000-05-01), McKee et al.
patent: 3116057 (1994-07-01), None
patent: 2074310 (1981-10-01), None
Han Sung Jin
Kim Wan Soo
Kim Yang Kyeong
Ryu Jong Gwan
Leung Philip H.
LG Electronics Inc.
Ostrolenk Faber Gerb & Soffen, LLP
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