JPH0620771A - Microwave oven - Google Patents

Abstract

(57) [Abstract] [Purpose] To prolong the life of electrical components by lengthening the on / off cycle of multiple microwave oscillators. [Structure] The microwave oven has two microwave oscillating devices 1
0, 11 and thermistors 15, 16 for detecting the temperature of the oscillators 10, 11, two main relays 12, 13 for turning on / off the oscillators 10, 11 and outputs of the thermistors 15, 16. A heating control device (14) for controlling the main relays (12, 13) is provided. The heating control device 14 turns off the oscillating devices 10 and 11 whose temperature has risen during operation and turns on the other oscillating devices 11 and 10, so that the two microwave oscillating devices 10 and 11 are turned on.
Alternately turn on and off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven having a plurality of microwave oscillating devices, and more particularly to a microwave oven suitable for commercial use.

[0002]

2. Description of the Related Art Household microwave ovens having one microwave oscillating device are well known.

When a microwave oven is used for cooking and thawing frozen foods in restaurants and food wholesale stores, it is necessary to quickly provide warm meals.
It is important to be able to cook in a short time. For this reason, a commercial microwave oven having a plurality of microwave oscillators and having a high high-frequency output has been put into practical use. For example, the high frequency output of a commercial microwave oven having two microwave oscillating devices is about twice that of a household microwave oven, and the high frequency output of a commercial microwave oven having four microwave oscillating devices is of a household microwave oven. It is about four times higher, and some have even higher high-frequency output.

When food is heated and cooked in a commercial microwave oven (two-tube microwave oven) having two microwave oscillating devices, the two microwave oscillating devices are continuously operated at full power for a fixed time (for example, 30 seconds). The continuous heating method that operates automatically is adopted. In the case of thawing and heating,
An intermittent heating method is employed in which two microwave oscillating devices are simultaneously turned on (actuated) and turned off (actuated) at a fixed cycle. For example, in the case of 50% output in 30 second cycle,
Both of the two microwave oscillating devices are operated at full power for 15 seconds, and both of the two microwave oscillating devices are deactivated for the subsequent 15 seconds.

[0005]

Switching between operation and deactivation of the microwave oscillating device as described above is generally performed by opening and closing the main relay. However, in the conventional two-tube microwave oven, two microwaves are used. Since the intermittent heating method that simultaneously turns on and off the wave oscillator is adopted,
The off-cycle is short, and therefore the open / close cycle of the main relay is short. In the case of a commercial microwave oven, the frequency of use is high, and if it is high, it may be used about 300 times a day. As a result, the number of times the main relay is opened and closed becomes very large, and the life of the main relay and other electrical components is shortened.

A two-tube microwave oven is used 300 times a day, 250 times of which are continuously heated with full power for 30 seconds (cooking), 50 times of which are adiabatic heating for 10 minutes with a cycle of 30 seconds (thaw heating). ), The total number of opening / closing operations of the main relay per day is 1250. That is, in the case of continuous heating, the main relay is opened and closed once at one time, and therefore, the number of times of opening and closing of the main relay is 250 times by continuous heating 250 times a day. 3 for intermittent heating
Since the main relay is opened and closed once every 0 seconds, the number of times the main relay is opened and closed is 2 times per minute, and this is done for 10 minutes, so the number of times the main relay is opened and closed for adiabatic heating is 2 times.
It will be 0 times. And such adiabatic heating 50
The number of opening and closing of the main relay for adiabatic heating is 1000 times per day because it is performed once, and when this 1000 times and 250 times for continuous heating are combined, the number of opening and closing of the main relay per day is 1250 times. . Here, assuming that the designed life of the main relay is about 400,000, the number of days used is about 320 days (400000/1250). If such use is continued every day, the life of the main relay will be about one year at the longest. In addition to the main relay,
In the case of fuses, switches, magnetrons, and the like, when the intermittent operation is repeated, heat generation and cooling are repeated, so that there is a problem that durability is affected by a heat shock phenomenon and life of parts is shortened.

The object of the present invention is to solve the above problems,
An object of the present invention is to provide a microwave oven in which the on / off cycle of the microwave oscillating device is extended to prolong the life of electrical components.

[0008]

A microwave oven according to the present invention is a microwave oven having a plurality of microwave oscillating devices, wherein each microwave oscillating device is repeatedly operated and deactivated, and as a whole, a part of the microwave oven is always operated. The microwave oscillating device is operated.

Each microwave oscillating device is provided with a temperature detector so that the operation of the microwave oscillating device whose temperature has risen during operation is stopped and the remaining microwave oscillating devices are operated in sequence. Sometimes.

In some cases, two microwave oscillating devices are provided and the two microwave oscillating devices are operated alternately.

A temperature detector is provided in each of the two microwave oscillating devices so that the operation of the microwave oscillating device whose temperature has risen during operation is stopped and the other microwave oscillating device is operated. Sometimes.

[0012]

Since some microwave oscillating devices are always operated, the on / off cycle of each microwave oscillating device can be lengthened.

Each microwave oscillating device is provided with a temperature detector, the operation of the microwave oscillating device whose temperature has risen during operation is stopped, and the remaining microwave oscillating devices are operated in sequence. Also in this case, the on / off cycle of each microwave oscillation device becomes long.

Even when two microwave oscillating devices are provided and the two microwave oscillating devices are operated alternately, the on / off cycle of each microwave oscillating device is lengthened. You can

Each of the two microwave oscillating devices is provided with a temperature detector so that the operation of the microwave oscillating device whose temperature has risen during operation is stopped and the other microwave oscillating device is operated. Also, the on / off cycle of each microwave oscillation device becomes long.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment in which the present invention is applied to a commercial microwave oven will be described below with reference to the drawings.

1 and 2 show a first embodiment.

FIG. 1 is a block diagram showing the configuration of the main part of a two-tube microwave oven for business use.

As shown in FIG. 1, the microwave oven is equipped with two microwave oscillating devices (10) and (11).
0) and (11) are connected to the heating control device (14) via main relays (12) and (13), respectively. Although not shown, the oscillators (10) and (11) are provided with a magnetron or the like. The heating control device (14) is equipped with a computer, and controls on / off of the oscillation devices (10) and (11) by controlling opening and closing of the main relays (12) and (13).

In this microwave oven, in the case of heating and cooking, as in the conventional case, continuous heating is performed in which the two oscillating devices (10) and (11) are continuously operated at full power for a fixed time (for example, 30 seconds).

In the case of thawing heating, as shown in the timing chart of FIG. 2, the two main relays (12) and (13) are alternately turned on and off at regular intervals (for example, 5 minutes). For example, only the first main relay (12) is turned on for the first fixed time, and the second main relay (1) is turned on for the next fixed time.
The operation of turning on only 3) is repeated. As a result, the first microwave oscillating device (10) for the first fixed time
Only the second microwave oscillating device (11) is turned on for the next fixed time, and the two oscillating devices (10) and (11) alternate every other fixed time. Is turned on and off.

As described above, by alternately turning on and off the two oscillators (10) and (11), these on / off cycles, that is, turning on / off of the main relays (12) and (13). The off cycle can be extended.

3 and 4 show a second embodiment.

FIG. 3 is a block diagram showing the structure of the main part of a two-tube microwave oven for business use, and the same parts as those in FIG. 1 are designated by the same reference numerals.

In this case, the oscillators (10) and (11) are provided with thermistors (15) and (16) which are temperature detectors, and their outputs are input to the heating control device (14).

The cooking process is the same as in the first embodiment.

In the case of thawing and heating, the heating control device (14) first turns on only one of the oscillators (10) and (11) and changes the temperature of the operating oscillators (10) and (11) to the thermistor (15). ) (16), if the temperature of the operating oscillator (10) (11) rises to a predetermined set value, the operating oscillator (10) (11) is turned off and the other By turning on the oscillators (11) (10),
The two oscillators (10) and (11) are turned on and off alternately. For example, as shown in the timing chart of FIG. 4, first, only the first main relay (12) is turned on, and only the first oscillator (10) is turned on. As a result, the first oscillator (10) starts oscillating at full power and heat generation. Then, the temperature of the first oscillator (10) is detected by the first thermistor (15), and if the temperature of the first oscillator (10) rises to the set value, the first main relay (12) is turned off. Then, at the same time as turning off the first oscillation device (10), the second main relay (13) is turned on and the second oscillation device (11) is turned on. Thereby, the second oscillator
Since (11) oscillates at full power and generates heat, the temperature of the second oscillator (11) is detected by the second thermistor (16) and if the temperature of the second oscillator (11) rises to the set value. For example, the second main relay (13) is turned off and the second oscillator (11) is turned off, and at the same time, the first main relay (12) is turned on and the first oscillator (10) is turned on. Hereinafter, the above operation is repeated during the set thawing and heating time.

In this way, when the temperature of the oscillating device (10) (11) in operation rises, the oscillating device (10) (11) is switched on and off to switch the two oscillating devices (10) ( By alternately turning on and off 11), the on / off cycle of these, that is, the on / off cycle of the main relays (12) and (13) can be lengthened.

As in the case of the conventional example, the two-tube microwave oven is used 300 times a day, of which 250 times are full-power cooking for 30 seconds (continuous heating) and 50 times are 5 times.
Assuming that the thawing heating (alternate heating) is performed at 0% output for 10 minutes, the number of opening / closing operations of the main relay per day will be calculated. In this case, one of the microwave
(10) If (11) is on for 5 minutes,
The total number of times the main relay is opened and closed per day is 300 times. That is, the number of times of opening and closing the main relay for heating and cooking is 250 times per day, as in the case of the conventional example. Since each microwave oscillating device is on for 5 minutes, each main relay is opened and closed once every 10 minutes, and the number of opening and closing of each main relay is 1 per 10 minutes of thawing and heating. It turns. Since such thawing heating is performed 50 times a day, the number of times of opening and closing the main relay for thawing heating becomes 50 times a day.
If 0 times and 250 times for continuous heating are combined, the number of opening / closing operations of the main relay per day will be 300 times. Here, assuming that the designed life of the main relay is about 400,000, the number of usage days is about 1333 days (400000/300), which is about four times that of the conventional one. The same applies to other parts, and the number of inrush currents flowing in the circuit during intermittent oscillation is reduced, so that the life of many parts is extended.

[0030]

According to the microwave oven of the present invention, as described above, the on / off cycle of each microwave oscillating device can be lengthened, so that the microwave oscillating device is turned on / off. The life of electrical components such as main relays can be extended.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a commercial two-tube microwave oven showing a first embodiment of the present invention.

FIG. 2 is a timing chart showing an example of operations of the microwave oscillator and the main relay in FIG.

FIG. 3 is a block diagram of a main part of a commercial two-tube microwave oven showing a second embodiment of the present invention.

FIG. 4 is a timing chart showing an example of operations of the microwave oscillator and the main relay in FIG.

[Explanation of symbols]

 (10) (11) Microwave oscillator (12) (13) Main relay (14) Heating controller (15) (16) Thermistor (temperature detector)

Claims (4)

[Claims] 1. In a microwave oven having a plurality of microwave oscillating devices, each microwave oscillating device is repeatedly operated and deactivated so that a part of the microwave oscillating devices is always operated as a whole. The microwave oven being made. 2. A microwave sensor is provided in each microwave oscillating device, the operation of the microwave oscillating device whose temperature has risen during operation is stopped, and the remaining microwave oscillating devices are operated in sequence. The microwave oven according to claim 1, 3. The microwave oven according to claim 1, further comprising two microwave oscillating devices, wherein the two microwave oscillating devices are operated alternately. 4. A temperature detector is provided in each of the two microwave oscillating devices, so that the operation of the microwave oscillating device whose temperature has risen during operation is stopped and the other microwave oscillating device is operated. The microwave oven according to claim 3, which has been made.