Electric heating – Microwave heating – With control system
Reexamination Certificate
2000-10-12
2002-02-05
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
With control system
C219S681000, C219S757000, C126S02100R
Reexamination Certificate
active
06344636
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a microwave oven, and more particularly to, an apparatus and a method for detecting abnormal operation of parts of a microwave oven for preventing damage of interior parts of the microwave oven by detecting abnormal functions of parts in trouble.
DISCUSSION OF RELATED ART
FIG. 1
is a view showing a structure of heaters and a fan according to a first embodiment of related art microwave oven, and
FIG. 2
is a view showing a structure of heaters and a fan according to a second embodiment of related art microwave oven.
First Embodiment
In the related art microwave oven, as shown in
FIG. 1
, a plurality of heaters
7
,
9
,
11
disposed between a power supply and a ground are connected with relays
13
,
15
,
17
for controlling power supply for the respective heaters
7
,
8
,
9
in serial, that is, the power supply for the heaters
7
,
8
,
9
is controlled by the on/off operation of the relays
13
,
15
17
.
The heaters
7
,
9
,
11
are connected with a plurality of cooling fans
19
,
21
,
23
,
25
for preventing overheating due to the heat generated by the heaters when the heaters
7
,
9
,
11
operate. The cooling fans
19
,
21
,
23
,
25
are also connected to relays
27
,
29
,
31
,
33
in serial so that the operation of the cooling fans
19
,
21
,
23
,
25
is controlled by the relays
27
,
29
,
31
,
33
.
Even though unshown, a controller part (unshown) controls the operation of the relays
13
,
15
,
17
for controlling the power supply for the heaters and the relays
27
,
29
,
31
,
33
for controlling the power supply for the cooling fans. That is, the control part controls the operation of the heaters and the cooling fans according to a current cooking.
In order to prevent damage of parts due to the overheating of the heaters, a thermostat
1
is connected to the heaters. The thermostat
1
is a switch element to be turned on or off above a predetermined temperature.
Therefore, if the thermostat
1
is controlled to be turned off above a predetermined temperature, the power supply for the heaters are shut off in response to the turning off of the thermostat when the temperature is higher than the predetermined temperature by the overheating of the heaters.
Second Embodiment
In the second embodiment, the same reference symbols are utilized for the same components as shown in the first embodiment.
A plurality of heaters
7
,
9
,
11
are connected between a power supply and a ground in parallel. The respective heaters
7
,
9
,
11
are connected with relays
13
,
15
,
17
for controlling power supply for the respective heaters, that is, the power supply for the heaters
7
,
8
,
9
is controlled by the on/off operation of the relays
13
,
15
17
.
The heaters
7
,
9
,
11
are connected with a plurality of cooling fans
19
,
21
,
23
,
25
for preventing overheating due to the heat generated by the heaters when the heaters
7
,
9
,
11
operate. The cooling fans
19
,
21
,
23
,
25
are also connected to relays
27
,
29
,
31
,
33
in serial so that the operation of the cooling fans
19
,
21
,
23
,
25
is controlled by the relays
27
,
29
,
31
,
33
.
Even though unshown, a controller part (unshown) controls the operation of the relays
13
,
15
,
17
for controlling the power supply for the heaters and the relays
27
,
29
,
31
,
33
for controlling the power supply for the cooling fans. That is, the control part controls the operation of the heaters and the cooling fans according to a current cooking.
In order to prevent damage of parts due to the overheating of the heaters, a plurality of thermostats
1
,
3
,
5
is connected to the heaters. The thermostats
1
,
3
,
5
are to be a switch element to be turned on or off above a predetermined temperature.
Therefore, if the thermostats are controlled to be turned off above a predetermined temperature, the power supply for the heaters are shut off in response to the turning off of the thermostats when the temperature is higher than the predetermined temperature by the overheating of the heaters.
Now, a process for controlling the operation of the related art heaters and the fans described as above.
The control part (unshown) determines a cooking to be currently processed, and controls operation of the heaters
7
,
9
,
11
according to power consumption of the cooking. If the currently processing cooking is required to drive the heater
7
only, the control part turns on the relay
13
to supply power to the heater
7
.
If the relay
13
is turned on, the heater
7
is supplied with power to generate heat to perform the cooking.
If the current cooking is required to drive all the heaters
7
,
9
,
11
, all the relays
13
,
15
,
17
are turned on such that the heaters
7
,
9
,
11
begin to operate in response to the turning on of the relays
13
,
15
,
17
.
On the other hand, if the heater
7
is driven, the controller (unshown) drives the cooling fan
19
. While all the heaters
7
,
9
,
11
are driven, the controller drives all the cooling fans
19
,
21
,
23
.
That is, the cooling fans
19
,
21
,
23
cool the heat generated by the heaters in association with the operation of the heaters
7
,
9
, and
11
.
The related art apparatus for controlling the heaters and the fans has, however, a disadvantage that it is impossible to detect malfunction of the heaters and the fans. Accordingly, if the heater
7
continues to operate even though the cooling fan
19
is in trouble, environmental parts of the heater
7
are damaged or fire happens due to the overheating of the heater
7
.
In order to resolve this disadvantage, thermostats
1
,
3
,
5
are mounted around the heaters
7
,
9
,
11
for forcibly shutting off the power supply for the heaters
7
,
9
,
11
if the generated heat is higher than a predetermined temperature.
However, the construction of the related art apparatus for controlling the heaters and the fans with the thermostats
1
,
3
,
5
is too complicated and increase the manufacturing cost. And, such a related art apparatus still has disadvantage that it is impossible to detect the malfunction of the heaters or the fans.
Accordingly, it is required to repair the microwave oven due to the re-driving of the microwave oven since the microwave oven is controlled in a worst state by the thermostats
1
,
3
,
5
when the fans are in trouble, thereby decreasing the reliability of the product.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to solve at least the problems and disadvantages of the related art.
Another object of the present invention is to provide an apparatus and a method for detecting abnormal operation of parts of a microwave oven for preventing fire or damage of the parts possibly caused due to the abnormal operation of the parts in trouble in advance.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purposes of the invention, as embodied and broadly described herein, in a microwave oven with a high voltage transformer (HVT′), an apparatus for detecting abnormal operation of parts of the microwave oven comprising: a plurality of heaters connected between a power supply and a ground potential in parallel; a plurality of relays for controlling power supply for the plurality of heaters; cooling fans to be driven in response to the operation of the heaters for cooling heat generated by the heaters; a current transformer for detecting currents used by the eaters, the cooling fan, and the high pressure transformer; and a control part for monitoring operational states of the heaters, the cooling fan and the high pressure transformer according to comparison
Fleshner & Kim LLP
Leung Philip H.
LG Electronics Inc.
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