CA1196968A - Microwave generator cooling apparatus - Google Patents
Microwave generator cooling apparatusInfo
- Publication number
- CA1196968A CA1196968A CA000409754A CA409754A CA1196968A CA 1196968 A CA1196968 A CA 1196968A CA 000409754 A CA000409754 A CA 000409754A CA 409754 A CA409754 A CA 409754A CA 1196968 A CA1196968 A CA 1196968A
- Authority
- CA
- Canada
- Prior art keywords
- generator
- temperature
- microwave oven
- cooling air
- rate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/66—Circuits
- H05B6/666—Safety circuits
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/642—Cooling of the microwave components and related air circulation systems
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Electric Ovens (AREA)
Abstract
MICROWAVE GENERATOR COOLING APPARATUS
ABSTRACT OF THE DISCLOSURE
A microwave oven cooling apparatus wherein air is flowed in heat transfer association with the microwave energy generator of the oven apparatus for cooling the same.
A control is provided for causing the air to be delivered at a relatively low rate upon initiation of energization of the generator, to gradually increase the rate of flow as the generator heats up, and modulate the rate of flow to maintain a substantially constant temperature of the generator after the generator reaches normal operating temperature. In the illustrated embodiment, the control includes a sensor for sensing the temperature of heat dissipating fins associated with the generator for effecting the automatic temperature regulation of the generator.
ABSTRACT OF THE DISCLOSURE
A microwave oven cooling apparatus wherein air is flowed in heat transfer association with the microwave energy generator of the oven apparatus for cooling the same.
A control is provided for causing the air to be delivered at a relatively low rate upon initiation of energization of the generator, to gradually increase the rate of flow as the generator heats up, and modulate the rate of flow to maintain a substantially constant temperature of the generator after the generator reaches normal operating temperature. In the illustrated embodiment, the control includes a sensor for sensing the temperature of heat dissipating fins associated with the generator for effecting the automatic temperature regulation of the generator.
Description
~6!~8 MICROWA~E GENERATOR COOLING APPARAl'US
BACKGROUND OF TH~ INVENTION
Field of the Invention This invention relates to microwave ovens and in particular to means for provlding cooling air therein.
Description of the Bac]~ground Art In the conventional microwave oven, a microwave energy generator is energized to provide microwave energy to the oven cavity through suitable wave guides. The gen-erator develops heat in the operation thereof and it isconventional to provide cooling air flow in heat transfer therewith to prevent overheating thereof. In certain of the prior art devices, the heated air is delivered into the cavity for effecting convective heating of food articles being heated thereon by the microwave energy and to dissipate moisture from the oven cavity.
One such microwave oven is illustrated in U. S.
Letters Patent No. 4,115,678 of Hajime Tahikawa et al. As disclosed therein, the apparatus includes means for automati-cally controlling the heating time by detecting the temperaturerise of the outlet air. In order to prevent moisture deposition in the heating chamber, a fan control increases the fan speed when the temperature at the chamber outlet increases, or when a manual rather than an automatic heating time is desired.
In U. S. Letters Patent No. 3,716,687, Ronald J.
W. Constable discloses a microwave oven having a switch for controlling the fan motor so that the fan can be operated when required.
SUMMARY OF THE INVENTION
.
The present invention comprehends an impxoved control , ~
:~969~8 for controlling the operation of the generator cooling fan in a microwave oven structure~
More specifically, the control means of the present invention includes means for causiny the cooling fan to pro-vide a relatively low rate of flow when the generator is energized while at a low temperature, to increase the rate of flow as a function of the rise in temperature of the generator following initial energization, and to modulate the rate of flow about a preselected rate during further energization of the generator in the event the temperature thereof reaches a preselected elevated temperature.
In the illustrated embodiment, the control means includes a temperature sensor in thermal contact with the generator, and more specifically, in thermal contact there-with through heat dissipating means thereon.
In the illustrated embodiment, the low rate of air flow is approximately one-half tha-t of the preselected rate utilized when the generator is at normal operating temperature.
By providing a relatively low speed to the cooling fan for a period of time prior to the generator reaching the normal operating temperature, a relatively low noise operation is o~tained.
The improved control provides improved energy usage efficiency in addition to the improved quiet operation.
Thus, the microwave oven generator cooling means of the present invention is extremely simple and economical of construction while yet providing the highly desirable features discussed above.
BRIEF DESCRIPTION OF THE DRAWING
O-ther features and advantages of -the invention will be apparent from the following description taken in connection with the accompanying drawing ~7herein:
FIGURE 1 is a schematic front elevation illustrat-ing a microwave oven structure utilizing a regulator cooling fan control embodying the invention;
FIGURE 2 is a block diagram illustrating the control; and FIGURE 3 is a wiring diagram illustrating in greater detail the control circuitry~
DBSCRIPTION OF THE PREFERRBD EMBODIMENT
In the illustrative embodiment of the invention as disclosed in the drawing, a microwave oven generally designated 10 is shown to comprise an outer cabinet 11 defining an oven cavity 12 selectivel~ closed by a door 13.
Microwave energy is delivered to the cavity from a generator 14 through a suitable wave guide 15. A fan 16 driven by a suitable electric motor 17 is provided for cooling the generator in operation of the oven. The fan blows ambient temperature air over the generator and at
BACKGROUND OF TH~ INVENTION
Field of the Invention This invention relates to microwave ovens and in particular to means for provlding cooling air therein.
Description of the Bac]~ground Art In the conventional microwave oven, a microwave energy generator is energized to provide microwave energy to the oven cavity through suitable wave guides. The gen-erator develops heat in the operation thereof and it isconventional to provide cooling air flow in heat transfer therewith to prevent overheating thereof. In certain of the prior art devices, the heated air is delivered into the cavity for effecting convective heating of food articles being heated thereon by the microwave energy and to dissipate moisture from the oven cavity.
One such microwave oven is illustrated in U. S.
Letters Patent No. 4,115,678 of Hajime Tahikawa et al. As disclosed therein, the apparatus includes means for automati-cally controlling the heating time by detecting the temperaturerise of the outlet air. In order to prevent moisture deposition in the heating chamber, a fan control increases the fan speed when the temperature at the chamber outlet increases, or when a manual rather than an automatic heating time is desired.
In U. S. Letters Patent No. 3,716,687, Ronald J.
W. Constable discloses a microwave oven having a switch for controlling the fan motor so that the fan can be operated when required.
SUMMARY OF THE INVENTION
.
The present invention comprehends an impxoved control , ~
:~969~8 for controlling the operation of the generator cooling fan in a microwave oven structure~
More specifically, the control means of the present invention includes means for causiny the cooling fan to pro-vide a relatively low rate of flow when the generator is energized while at a low temperature, to increase the rate of flow as a function of the rise in temperature of the generator following initial energization, and to modulate the rate of flow about a preselected rate during further energization of the generator in the event the temperature thereof reaches a preselected elevated temperature.
In the illustrated embodiment, the control means includes a temperature sensor in thermal contact with the generator, and more specifically, in thermal contact there-with through heat dissipating means thereon.
In the illustrated embodiment, the low rate of air flow is approximately one-half tha-t of the preselected rate utilized when the generator is at normal operating temperature.
By providing a relatively low speed to the cooling fan for a period of time prior to the generator reaching the normal operating temperature, a relatively low noise operation is o~tained.
The improved control provides improved energy usage efficiency in addition to the improved quiet operation.
Thus, the microwave oven generator cooling means of the present invention is extremely simple and economical of construction while yet providing the highly desirable features discussed above.
BRIEF DESCRIPTION OF THE DRAWING
O-ther features and advantages of -the invention will be apparent from the following description taken in connection with the accompanying drawing ~7herein:
FIGURE 1 is a schematic front elevation illustrat-ing a microwave oven structure utilizing a regulator cooling fan control embodying the invention;
FIGURE 2 is a block diagram illustrating the control; and FIGURE 3 is a wiring diagram illustrating in greater detail the control circuitry~
DBSCRIPTION OF THE PREFERRBD EMBODIMENT
In the illustrative embodiment of the invention as disclosed in the drawing, a microwave oven generally designated 10 is shown to comprise an outer cabinet 11 defining an oven cavity 12 selectivel~ closed by a door 13.
Microwave energy is delivered to the cavity from a generator 14 through a suitable wave guide 15. A fan 16 driven by a suitable electric motor 17 is provided for cooling the generator in operation of the oven. The fan blows ambient temperature air over the generator and at
2~ least a portion of the heated air flows through the cavity 14 before exiting the cabinet 11. The air flow may be that disclosed in U.S. Letters Patent No. 4,123,643.
As shown in Figure 2, the invention comprehends the provision of improved control means generally designated 18 for controlling the speed of the fan motor 17 for varying the rate of flow of cooling air against the generator 14 as a function of the temperature of the generator~ More specifically, a temperature sensing element 52 is provided which senses the temperature of 3Q heat dissipating fins 62 associated with PA-5133 0-~-USA
generator 14 and provides a signal to the speed control 18 for use in controlling the speed of the fan motor 17.
Broadly, the control 18 is arranged to cause the fan 16 to provide a relatively low rate of flow of the cooling air when the generator is energized and a-t a low temperature.
The control causes an increase in the rate of flow of the ` air as a function of the rise in temperature of khe generator following the initial energization thereof, and effects a modulation of the rate of flow of the air about a preselected rate during further energization of the generator when the generator temperature reaches a preselected normal operating elevated temperature.
In the illustrated embodiment, the control 18 causes the fan motor 17 to run at approximately one-half full speed at initial energization of the circuit. The control modulates the fan speed after the generator reaches its normal operating temperature continuously until the oven is de-energized.
As a result of the low speed fan operation at ~ startup, the operation of the oven is made to be relatively - 20 ~uiet, which is desideratum in applications such as domestic installations of the microwave oven~
Control 18 is more specifically illustrated in Figure 3 of the drawing wherein power to the control is pro-vided from conventional power supply leads Ll and L2, which may comprise conventional 120-volt AC supply leads. A fuse 19 may be provided in power supply lead Ll. The magnetron generator 14 is energized from a power transformer generally designated 20 which includes a first secondary winding 21 and a primary winding 22. Primary winding 22 is connected between a first power lead 23 and a second power lead 24.
PA-5133-0-P~M-USA
~69~8 Lead 24 is connected through a normally open secondary door interlock switch 25 associated with oven cavity door 13, to power supply lead L2.
The control circuit 18 further includes a timer switch 26 connected in series with a normally open primary door interlock switch 27 and a normally closed monitor switch 28 from power supply lead L2 through the fuse 19 to power supply lead Ll.
The control circuit 18 further includes a momentary contac-t start switch 29 and a cook relay generally designated 30, having a switch contact 31 connected to lead 23 through switches 27 and 26 for providing power thereto upon release of the start switch 29. A coil 32 of the cook relay has one end connected to switch 29 and the opposite end connected through a thermal protector switch 33 to the secondary door interlock switch 25. Start switch 29 is connected to lead 23 through a resistor 34 and a power lead 35.
A parallel connection of an oven light 36 and a dial light 37 is connected from power supply lead Ll through a single pole, double throw oven switch 38 and fuse 19 to power supply lead Ll.
Timer switch 26 is controlled by a suitable timer motor 39. The control circuit further includes a cook indi-cator 40 connected between leads 23 and 24 A stirrer motor41 is also connected between leads 23 and 24. I'he control circuit fuxther includes a conventional~solid state power selector 42 and a read relay 43.
! The power transformer 20 further includes a second secondary winding 44 across which is connected a series con-nection of a hiyh voltage rectifier 45 and a high vol-tage PA-5133-0-RN-US~
~9~
capaci-tor 46. ~ high holding value resistor 47 is connected in parallel with capacitor 46j as shown. The connection be-tween rectifier 45 and capacitor 46 is connected through a normally open switch contact 48 of the read relay 43 to one side of the secondary winding 21 of transformer 20.
Fan motor 17 is connected from lead 23 on one side to a fan motor speed control circuit 8 on the other side.
The speed control circuit 8 includes voltage divider resistors 49 and 50 connected to lead 24. In parallel with the series connected resistors 49 and 50 is a series connection of a time delay resistor 51, a thermistor 52, ana a capacitor 53. In parallel with capacitor 53 is a series connection of a time delay resistor 54 and a capacitor 55.
The juncture between resistor 54 and capacitor 55 is connected to a diac 56 which, in turn, is connected to the control electrode of a triac 57.
~ snubber circuit, including a series connection of a resistor 58 and capacitor 59, is connected in parallel with triac 57 from lead 24 to fan motor 17.
Thermistor 52 comprises a negative temperature co-efficient thermistor wherein the resistance decreases as the temperature sensed hy the thermistor increases. Diac 56 presents a high voltage to the control terminal 60 of triac 57 until the voltage on the diac input reaches a level caus-ing it to breakover and thereby present a short circuit for the voltage on capacitor 55 to the control input 60 of the triac. Thus, the control diac provides a variable firing time for the triac which, in turn, controls the operation of the fan motor 17 connected in series therewith to provide the desired speed control discussed above.
a6~
The resistors 49, 50, 51 and 54 cooperate with the reslstance of the thermistor 52 -to provide a preselected minimum fan motor speed at the normal ambient temperature.
In the illustrated embodiment, this speed is approximately one-half the full speed of the motor 17. As the temperature of the magnetron generator 14 increases, the temperature sensed by the thermistor sensor 52 of the heat dissipating means of the generator rises so as to lower the resistance of the thermistor and thereby decrease the time delay before the diac takes over to turn on triac 57. This results in a gradually increasing speed of the fan motor as the tem~erature of the magnetron generator rises after initial energization thereof. Ata sensedoperating temperature of the generator of approximately 155 F., the motor operates at a preselected speed slightly less than full speed. Thus, the speed of the motor remains under control of the speed control circuit 8 even at the normal operating temperature of the generator and the circuit 8 continues to modulate the fan speed and there-fore the air flow rate in accordance with the temperature sensed by thermistor 52. The snubber circuit resistance 58 and capacitor 59 limit the rise in the voltage when the triac turns off to effectively prevent self turn-on thereof.
As the speed of the fan motor 17 is caused to be approximately one-half the normal full speed when the gen-erator is at ambient temperature or close thereto, the noise level of the fan is effectively minimized. Further, energy usage efficiency is effectively maximized, particularly where the microwave oven is utilized for short heating cycles where-in the temperature of the generator normally does no-t reach 0 its elevated normal operating temperature.
The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.
As shown in Figure 2, the invention comprehends the provision of improved control means generally designated 18 for controlling the speed of the fan motor 17 for varying the rate of flow of cooling air against the generator 14 as a function of the temperature of the generator~ More specifically, a temperature sensing element 52 is provided which senses the temperature of 3Q heat dissipating fins 62 associated with PA-5133 0-~-USA
generator 14 and provides a signal to the speed control 18 for use in controlling the speed of the fan motor 17.
Broadly, the control 18 is arranged to cause the fan 16 to provide a relatively low rate of flow of the cooling air when the generator is energized and a-t a low temperature.
The control causes an increase in the rate of flow of the ` air as a function of the rise in temperature of khe generator following the initial energization thereof, and effects a modulation of the rate of flow of the air about a preselected rate during further energization of the generator when the generator temperature reaches a preselected normal operating elevated temperature.
In the illustrated embodiment, the control 18 causes the fan motor 17 to run at approximately one-half full speed at initial energization of the circuit. The control modulates the fan speed after the generator reaches its normal operating temperature continuously until the oven is de-energized.
As a result of the low speed fan operation at ~ startup, the operation of the oven is made to be relatively - 20 ~uiet, which is desideratum in applications such as domestic installations of the microwave oven~
Control 18 is more specifically illustrated in Figure 3 of the drawing wherein power to the control is pro-vided from conventional power supply leads Ll and L2, which may comprise conventional 120-volt AC supply leads. A fuse 19 may be provided in power supply lead Ll. The magnetron generator 14 is energized from a power transformer generally designated 20 which includes a first secondary winding 21 and a primary winding 22. Primary winding 22 is connected between a first power lead 23 and a second power lead 24.
PA-5133-0-P~M-USA
~69~8 Lead 24 is connected through a normally open secondary door interlock switch 25 associated with oven cavity door 13, to power supply lead L2.
The control circuit 18 further includes a timer switch 26 connected in series with a normally open primary door interlock switch 27 and a normally closed monitor switch 28 from power supply lead L2 through the fuse 19 to power supply lead Ll.
The control circuit 18 further includes a momentary contac-t start switch 29 and a cook relay generally designated 30, having a switch contact 31 connected to lead 23 through switches 27 and 26 for providing power thereto upon release of the start switch 29. A coil 32 of the cook relay has one end connected to switch 29 and the opposite end connected through a thermal protector switch 33 to the secondary door interlock switch 25. Start switch 29 is connected to lead 23 through a resistor 34 and a power lead 35.
A parallel connection of an oven light 36 and a dial light 37 is connected from power supply lead Ll through a single pole, double throw oven switch 38 and fuse 19 to power supply lead Ll.
Timer switch 26 is controlled by a suitable timer motor 39. The control circuit further includes a cook indi-cator 40 connected between leads 23 and 24 A stirrer motor41 is also connected between leads 23 and 24. I'he control circuit fuxther includes a conventional~solid state power selector 42 and a read relay 43.
! The power transformer 20 further includes a second secondary winding 44 across which is connected a series con-nection of a hiyh voltage rectifier 45 and a high vol-tage PA-5133-0-RN-US~
~9~
capaci-tor 46. ~ high holding value resistor 47 is connected in parallel with capacitor 46j as shown. The connection be-tween rectifier 45 and capacitor 46 is connected through a normally open switch contact 48 of the read relay 43 to one side of the secondary winding 21 of transformer 20.
Fan motor 17 is connected from lead 23 on one side to a fan motor speed control circuit 8 on the other side.
The speed control circuit 8 includes voltage divider resistors 49 and 50 connected to lead 24. In parallel with the series connected resistors 49 and 50 is a series connection of a time delay resistor 51, a thermistor 52, ana a capacitor 53. In parallel with capacitor 53 is a series connection of a time delay resistor 54 and a capacitor 55.
The juncture between resistor 54 and capacitor 55 is connected to a diac 56 which, in turn, is connected to the control electrode of a triac 57.
~ snubber circuit, including a series connection of a resistor 58 and capacitor 59, is connected in parallel with triac 57 from lead 24 to fan motor 17.
Thermistor 52 comprises a negative temperature co-efficient thermistor wherein the resistance decreases as the temperature sensed hy the thermistor increases. Diac 56 presents a high voltage to the control terminal 60 of triac 57 until the voltage on the diac input reaches a level caus-ing it to breakover and thereby present a short circuit for the voltage on capacitor 55 to the control input 60 of the triac. Thus, the control diac provides a variable firing time for the triac which, in turn, controls the operation of the fan motor 17 connected in series therewith to provide the desired speed control discussed above.
a6~
The resistors 49, 50, 51 and 54 cooperate with the reslstance of the thermistor 52 -to provide a preselected minimum fan motor speed at the normal ambient temperature.
In the illustrated embodiment, this speed is approximately one-half the full speed of the motor 17. As the temperature of the magnetron generator 14 increases, the temperature sensed by the thermistor sensor 52 of the heat dissipating means of the generator rises so as to lower the resistance of the thermistor and thereby decrease the time delay before the diac takes over to turn on triac 57. This results in a gradually increasing speed of the fan motor as the tem~erature of the magnetron generator rises after initial energization thereof. Ata sensedoperating temperature of the generator of approximately 155 F., the motor operates at a preselected speed slightly less than full speed. Thus, the speed of the motor remains under control of the speed control circuit 8 even at the normal operating temperature of the generator and the circuit 8 continues to modulate the fan speed and there-fore the air flow rate in accordance with the temperature sensed by thermistor 52. The snubber circuit resistance 58 and capacitor 59 limit the rise in the voltage when the triac turns off to effectively prevent self turn-on thereof.
As the speed of the fan motor 17 is caused to be approximately one-half the normal full speed when the gen-erator is at ambient temperature or close thereto, the noise level of the fan is effectively minimized. Further, energy usage efficiency is effectively maximized, particularly where the microwave oven is utilized for short heating cycles where-in the temperature of the generator normally does no-t reach 0 its elevated normal operating temperature.
The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.
Claims (10)
1. In a microwave oven having a microwave energy generator and means for flowing cooling air in heat transfer associ-ation with said generator, the improvement comprising:
control means for causing the means for flowing cooling air to (a) provide a relatively low rate of flow when the generator is initially energized while at a low temperature, (b) increase the rate of flow as a function of a rise in temperature of the generator following initial energization, and (c) modulate the rate of flow about a preselected rate during further energization of the generator in the event the temperature thereof reaches a preselected elevated normal operating temperature.
control means for causing the means for flowing cooling air to (a) provide a relatively low rate of flow when the generator is initially energized while at a low temperature, (b) increase the rate of flow as a function of a rise in temperature of the generator following initial energization, and (c) modulate the rate of flow about a preselected rate during further energization of the generator in the event the temperature thereof reaches a preselected elevated normal operating temperature.
2. The microwave oven structure of claim 1 wherein said control means includes a temperature sensor in thermal contact with the generator.
3. The microwave oven structure of claim 1 wherein said generator includes heat dissipating wall means and said control means includes a temperature sensor in thermal contact with said generator through said wall means.
4. The microwave oven structure of claim 1 wherein said low rate of air flow is approximately one-half said pre-selected rate.
5. The microwave oven structure of claim 1 wherein said means for flowing cooling air includes an electrical motor and said control includes a gated rectifier for varying electrical power delivered to said means for flowing cooling air.
6. In a microwave oven having a cavity including means forming an opening for receiving items to be heated within the cavity, a door for removably closing said opening, generator means for producing electromagnetic energy within said cavity, means on said electromagnetic wave producing means for dissipating heat therefrom, and fan means including a motor drive for flowing air over said heat dissipating means, the improvement comprising:
sensing means for continuously sensing the temperature of said heat dissipating means; and control means for varying the speed of said fan motor means from a minimum level to elevated levels less than the maximum operating speed of the fan motor dependent on the temperature of said heat dissipating means continuously being sensed by said sensing means.
sensing means for continuously sensing the temperature of said heat dissipating means; and control means for varying the speed of said fan motor means from a minimum level to elevated levels less than the maximum operating speed of the fan motor dependent on the temperature of said heat dissipating means continuously being sensed by said sensing means.
7. The microwave oven structure of claim 6 wherein said heat dissipating means comprise cooling fins on said generator means.
8. The microwave oven structure of claim 6 wherein said minimum level is approximately one-half said maximum level.
9. In a microwave oven having a microwave energy generator and means for flowing cooling air in heat transfer associ-ation with said generator, the improvement comprising:
means for directly sensing the temperature of the generator; and control means responsive to said sensing means for causing the means for flowing cooling air to provide a reduced rate of cooling air flow at all times during operation of the generator including when the directly sensed temperature of the generator reaches a preselected normal operating temperature thereof, whereby the noise produced by operation of the means for flowing the cooling air is effectively minimized.
means for directly sensing the temperature of the generator; and control means responsive to said sensing means for causing the means for flowing cooling air to provide a reduced rate of cooling air flow at all times during operation of the generator including when the directly sensed temperature of the generator reaches a preselected normal operating temperature thereof, whereby the noise produced by operation of the means for flowing the cooling air is effectively minimized.
10. The microwave oven structure of claim 9 wherein said control means further includes means for modulating the operation of the means for flowing cooling air to modulate the generator temperature substantially about its normal operating temperature as a result of said preselected temperature of the generator being directly sensed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US33676882A | 1982-01-04 | 1982-01-04 | |
| US336,768 | 1982-01-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1196968A true CA1196968A (en) | 1985-11-19 |
Family
ID=23317571
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000409754A Expired CA1196968A (en) | 1982-01-04 | 1982-08-19 | Microwave generator cooling apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1196968A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5780822A (en) * | 1994-11-28 | 1998-07-14 | Lg Electronics Inc. | Apparatus and method for cooling thermopile of microwave oven |
| US5814794A (en) * | 1995-02-28 | 1998-09-29 | Samsung Electronics Co., Ltd. | Temperature control apparatus of microwave oven and method thereof |
| EP1207720A2 (en) * | 2000-11-08 | 2002-05-22 | Samsung Electronics Co., Ltd. | Microwave oven with variable speed cooling fan |
| US20150382408A1 (en) * | 2010-12-21 | 2015-12-31 | Whirlpool Corporation | Methods of controlling cooling in a microwave heating apparatus and apparatus thereof |
| EP3364109A1 (en) * | 2017-02-17 | 2018-08-22 | Electrolux Appliances Aktiebolag | Cooking oven |
-
1982
- 1982-08-19 CA CA000409754A patent/CA1196968A/en not_active Expired
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5780822A (en) * | 1994-11-28 | 1998-07-14 | Lg Electronics Inc. | Apparatus and method for cooling thermopile of microwave oven |
| US5814794A (en) * | 1995-02-28 | 1998-09-29 | Samsung Electronics Co., Ltd. | Temperature control apparatus of microwave oven and method thereof |
| EP1207720A2 (en) * | 2000-11-08 | 2002-05-22 | Samsung Electronics Co., Ltd. | Microwave oven with variable speed cooling fan |
| EP1207720A3 (en) * | 2000-11-08 | 2005-06-15 | Samsung Electronics Co., Ltd. | Microwave oven with variable speed cooling fan |
| US20150382408A1 (en) * | 2010-12-21 | 2015-12-31 | Whirlpool Corporation | Methods of controlling cooling in a microwave heating apparatus and apparatus thereof |
| US10064247B2 (en) * | 2010-12-21 | 2018-08-28 | Whirlpool Corporation | Methods of controlling cooling in a microwave heating apparatus and apparatus thereof |
| US10912161B2 (en) | 2010-12-21 | 2021-02-02 | Whirlpool Corporation | Methods of controlling cooling in a microwave heating apparatus and apparatus thereof |
| US11818826B2 (en) | 2010-12-21 | 2023-11-14 | Whirlpool Corporation | Methods of controlling cooling in a microwave heating apparatus and apparatus thereof |
| EP3364109A1 (en) * | 2017-02-17 | 2018-08-22 | Electrolux Appliances Aktiebolag | Cooking oven |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4191875A (en) | Fan speed control used in induction cooking apparatus | |
| US4401884A (en) | Method of controlling heating in food heating apparatus including infrared detecting system | |
| US5894396A (en) | Inrush current protection circuit | |
| US4533809A (en) | Microwave ovens and methods of cooking food | |
| EP0889672B1 (en) | Ventilation system for electrical food-cooking appliances comprising a cooking hob and an oven | |
| US4620078A (en) | Power control circuit for magnetron | |
| CA1196968A (en) | Microwave generator cooling apparatus | |
| GB2067857A (en) | Power control apparatus | |
| KR100284545B1 (en) | Magnetron Drive Control Method of Microwave Oven | |
| EP0764390B1 (en) | Microwave ovens | |
| EP1388275B1 (en) | Method and apparatus for controlling an electric cooking appliance | |
| KR100681578B1 (en) | Microwave fan motor control circuit | |
| KR100517742B1 (en) | Damper controlling apparatus of microwave oven | |
| KR0145023B1 (en) | Cooling device for magnetron and high voltage transformer | |
| EP0981265B1 (en) | Microwave oven providing a security to the high-voltage-transformer | |
| KR100505245B1 (en) | Induction heating rice cooker's inverter circuit | |
| KR0138559B1 (en) | Power control device of microwave oven | |
| EP0142958A2 (en) | Microwave ovens and methods of cooking food | |
| KR100212258B1 (en) | Inrush Current Prevention Circuit of Mechanical Microwave | |
| KR19980085394A (en) | Inrush current prevention and fire protection device of mechanical microwave oven | |
| JPH07289419A (en) | Induction heating type rice cooker | |
| CN117835477A (en) | Control method of microwave cooking appliance and microwave cooking appliance | |
| JPH07289421A (en) | Induction heating type rice cooker | |
| JPS6222050B2 (en) | ||
| JPS6022899Y2 (en) | Overheat prevention variable power rice cooker |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |