JP2001124345A - Microwave heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microwave oven to enable the uniform finishing state of identical foodstuff. SOLUTION: Based on a characteristic that the higher the temperature of a magnetron 5, the lower the output of the magnetron 5, the output of the microwave is held constant by variably controlling the airflow of a fan 6 detecting the temperature of the magnetron 5 by a thermistor 10. When the weight increase data is set up by a weight increase setting part of the weight of things to be heated 16, the heating condition for the things to be heated of a standard weight is changed by increasing the output of the microwave leaving the operating time as it is, and the magnetron 5 is driven based on the changed heating condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a microwave heating device such as a microwave oven.

[0002]

2. Description of the Related Art When a microwave oven operates, the temperature of a magnetron, which is an oscillation tube, rises. In order to cool it, a cooling device (comprising a fan and a fan motor)
Is sending wind.

However, due to the characteristics of the magnetron, the microwave output tends to decrease as the temperature increases. That is, FIG. 4 shows the time course of the microwave output value and the temperature of the magnetron fin unit when the fan motor is rotated at a constant speed during the oscillation of two magnetrons in a configuration using two magnetrons. The microwave output decreases with time as the fin temperature increases.

Therefore, in a convenience store or the like, when the same food is repeatedly heated by the same recipe, a large amount of microwave output is generated during the first heating operation because the magnetron is cooled. Was lowered, and there was a difference in the finished temperature at the same time setting.

In a microwave oven used in a convenience store or the like, for example, a food to be heated is roughly determined, and a heating time and an output for a specific food are registered in the microwave in advance, and one-touch operation is performed. Heating. When the number of the ingredients is increased to two or three, a double key (increase setting unit) is used to increase the operation time by 1.6 times when the operation time is double and by 2.times. When the operation time is three times. It was 1 time.

Therefore, when the double key is used, the operation time becomes long, and it is difficult to heat the food material for a short time.

[0007] It is an object of the present invention to provide a microwave heating apparatus capable of suppressing fluctuations in output due to an increase in the temperature of a magnetron and suppressing a difference in the finished state of foodstuffs. It is still another object of the present invention to provide a microwave heating device capable of suppressing an increase in heating time with an increase in the amount of food.

[0008]

SUMMARY OF THE INVENTION A first microwave heating apparatus according to the present invention comprises a heating chamber, a magnetron for supplying microwaves to the heating chamber, a cooling apparatus for cooling the magnetron, and a temperature of the magnetron. And a microcomputer that drives and controls the cooling device based on the temperature detected by the temperature detector so as to maintain the microwave output of the magnetron constant. . Further, the temperature detector is mounted on a radiation fin of the magnetron.
Further, the cooling device includes a fan and a motor that drives the fan to rotate, and the microcomputer includes:
The rotation speed of the motor is variably controlled based on the temperature detected by the temperature detector so that the microwave output of the magnetron is kept constant.

In this configuration, based on the characteristic that the output decreases as the temperature of the magnetron rises, the temperature of the fin portion of the magnetron is detected, and when the temperature exceeds a certain level, the air volume of the fan is increased. On the other hand, when the temperature of the magnetron drops, the air volume of the fan is reduced, so that the magnetron is always in a certain temperature range,
Make the output constant.

A second microwave heating apparatus according to the present invention comprises a heating chamber, a magnetron for supplying a microwave into the heating chamber, and an increase setting for setting increase information when the amount of the object to be heated is larger than a standard amount. And, when the increase information is not set by the increase setting section, the magnetron is driven based on heating conditions such as an operation time and a microwave output for a standard amount of the object to be heated, while the increase information is set by the increase setting section. Is set, the heating conditions for the standard amount of the object to be heated are changed so as to increase the microwave output while keeping the operation time, and a microcomputer that drives the magnetron based on the changed heating conditions. It is characterized by having. Further, when the change value of the microwave output based on the increase information exceeds the maximum microwave output that can be output by the magnetron, the change value of the microwave output is suppressed within the maximum microwave output, and the microwave output is reduced. It is characterized in that the operation time is increased by the reduced amount. Further, when the change value of the microwave output based on the increase information exceeds the maximum microwave output that can be output by the magnetron, the change value of the microwave output is suppressed to the maximum microwave output, and the microwave output is suppressed. It is characterized in that the operation time is increased by the amount of the operation.

[0011] In this configuration, when heating the microwave by twice the amount of the recipe having a microwave power that is not full power, the output is increased and the operation time is not increased. In other words, based on the stored heating time and the output for the standard amount, the operation is performed with the output as the output value multiplied by the doubling coefficient for the stored operation time as it was originally. If the output obtained by multiplying the output value by the doubling coefficient exceeds the full power of the device, the operating time is extended to compensate for the insufficient amount of heat. The extent of this extension is sufficient to make up for the insufficient amount of heat, and it is needless to say that it is not large as compared with the related art.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. In FIG. 1 showing a schematic configuration of a microwave oven, reference numeral 1 denotes a microwave oven main body, in which a heating chamber 3 for heating a heated object 2 such as a stored food or food material is formed. Reference numeral 4 denotes a turntable on which a heated object rotatably provided in the heating chamber 3 is placed. A door (not shown) that can be opened and closed is provided at the front opening of the heating chamber 3, and the article to be heated 2 is put in and out of the heating chamber 3 by this door. Reference numeral 5 denotes an oscillating tube for supplying a microwave into the heating chamber 3, that is, a magnetron, and two magnetrons are provided. A cooling device is provided for cooling each of the fin portions of the magnetron 5. The cooling device includes a fan 6 and a fan motor (to be described later) that rotationally drives the fan. A waveguide 7 for guiding the microwave generated by the magnetron 5 to the heating chamber 3 is provided outside the heating chamber 3, and the microwave guided by the waveguide 7 is applied to the wall surface 8 of the heating chamber 3. The object to be heated 2 is radiated from the microwave radiating port 9 formed in the heating chamber 3 into the heating chamber 3 and is microwave-heated.

Further, a temperature detector for detecting the temperature of the fin, ie, a thermistor 10, is provided at the fin portion of the magnetron, and the detected temperature information is sent to a control unit, ie, a microcomputer 11. This microcomputer 11
Controls the rotation of each fan motor, and controls the oscillation-pause of each magnetron 5 via a control line 12.

FIG. 2 shows an example in which the rotation of the fan motor is varied according to the temperature of the magnetron fin. There is a high-voltage transformer 13 for applying a high voltage to the magnetron 5, and a plurality of taps are provided on the primary circuit side of the transformer 13. The voltage of the primary circuit for magnetron oscillation is at terminal A2-
Provided between B. As a result, a high voltage is generated on the secondary side, and the magnetron 5 oscillates. One terminal of the fan motor 6a of the cooling device shares a terminal B, while the other terminal has a relay RL opened and closed by the microcomputer 11.
1, RL2 and RL3 are connected to terminals A1, A2 and A3, respectively.

At the start of operation, since the temperature of the magnetron 5 is low, the microcomputer 11 turns on the RL1, and the fan motor 6a receives a voltage stepped down from the voltage applied to the high voltage transformer 13 and rotates at a rotation speed lower than the standard. . When the temperature of the magnetron 5 rises and is detected by the thermistor 10 attached to the fin, the relay RL2
Alternatively, RL3 is turned on, and the rotation speed of the fan motor 6a increases. When RL3 is on, fan motor 6
a is applied with a voltage boosted from the voltage supplied to the high-voltage transformer 13, and the fan motor 6 a rotates at a higher rotation speed than the standard, thereby rapidly cooling the magnetron 5.

The rotation of the fan motor (not shown) for the other magnetron is, of course, similarly variably controlled.

By such control, each magnetron 5
Is constant, and the microwave output from each magnetron is kept constant.

FIG. 3 shows the operation unit 14 of the microwave oven. The operation unit 14 has a storage key 15 for storing the heating time and the microwave output with respect to the standard amount for each foodstuff in the microcomputer 11 in advance, and the food quantity is 2 for the standard food quantity stored in advance. An increase setting unit, that is, a double amount key 16 is provided for facilitating the handling when the number of times is doubled or tripled.

Here, for example, the first key is 500 g of meat.
It is assumed that a time of 10 minutes at a microwave output of 20% is stored by the storage key 15 as the thawing cooking. In such a situation, when performing thawing cooking of 500 g of meat, the first key is operated and the start key is operated. Then, since the increase information was not set by the double amount key 16, the microcomputer 11 drives and controls the magnetron 5 under heating conditions (microwave output 20%, time 10 minutes) based on the standard amount of 500 g.

On the other hand, when thawing 1000 g of meat (double amount), the first key is operated and the double amount key (double amount key) 16 is operated. Then, the microcomputer 11 increases the microwave output by 1.6 times of 20% (food 2
In this case, the heating time is changed to 32%, and the heating time is kept as it is (10 minutes), and the magnetron 5 is driven and controlled so that the microwave output is heated at 32% for 10 minutes.

The reason why the output is reduced at the time of thawing is to suppress local heating (heating unevenness). In addition, thawing is performed using the heat conduction inside the ingredients. Here, in the case of the above-mentioned food, assuming that the rated microwave output of the microwave oven is 1800 W, the output of 20% corresponds to 360 W. Also, 32% when the double key is used corresponds to 576W. Heating 500g of meat at 360W and 100
Considering that 0 g of meat is heated at 576 W, it can easily be imagined that even if the output is increased, the unevenness in heating does not increase due to heat conduction inside the food material.

Next, a description will be given of a process in a case where the output multiplied by the double factor exceeds the rated microwave output of the microwave oven. For example, assume that the second key stores 45 seconds of time at 50% output as heating of 200 g of soup. Now, when heating soup 600g (3 times amount), if the output is set to 2.1 times of 50% (corresponding to 3 times amount of food), it becomes 105% and the maximum output of microwave oven (rated microwave output) It exceeds 100%. In this case, the output is set to 100% or less, specifically, to 100%, and the shortage of heat is dealt with by extending the heating time.

The heating time is derived by the following calculation. The required heat is 45% at 105% power. That is, in the case of 100% output, 1.05 × 45 = 47.25 seconds.

The present invention is, of course, not limited to the above embodiment as long as it is within the scope of the present invention.

[0025]

According to the microwave heating device of the present invention,
Based on the characteristic that the output decreases when the temperature of the magnetron rises, the temperature of the magnetron can be detected and the fan air volume can be variably controlled, and the microwave output can be kept constant, so the same food finish The state can be kept constant.

Further, when heating a recipe whose microwave output is not at full power, the output time is increased but the operation time is not increased, so that the heating time can be suppressed from becoming longer. If the output obtained by multiplying the output value by the doubling coefficient exceeds the full power of the device, the operating time is extended to compensate for the insufficient amount of heat. However, the extent of this extension may be sufficient to compensate for the insufficient amount of heat, so that a longer time extension than in the prior art does not occur. In short, it is possible to efficiently heat the double amount food in a short time.

[Brief description of the drawings]

FIG. 1 is a sectional view of a microwave oven according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of the microwave oven.

FIG. 3 is a front view of an operation unit of the microwave oven.

FIG. 4 is a characteristic diagram showing magnetron characteristics.

[Explanation of symbols]

 3 Heating room 5 Magnetron 6 Fan 6a Fan motor 10 Thermistor 11 Microcomputer 14 Operation unit 16 Double key

Claims (6)

[Claims] 1. A heating chamber, a magnetron for supplying microwaves into the heating chamber, a cooling device for cooling the magnetron, a temperature detector for detecting a temperature of the magnetron, and a constant microwave output of the magnetron. And a microcomputer for controlling the driving of the cooling device based on the temperature detected by the temperature detector so as to maintain the temperature. 2. The microwave heating apparatus according to claim 1, wherein the temperature detector is mounted on a radiation fin of the magnetron. 3. The cooling device comprises a fan and a motor for driving the fan to rotate. The microcomputer is configured to maintain a constant microwave output of the magnetron based on a temperature detected by the temperature detector. 2. The microwave heating apparatus according to claim 1, wherein the number of rotations of the motor is variably controlled by the motor. 4. A heating chamber, a magnetron for supplying microwaves into the heating chamber, an increasing setting section for setting increasing information when the amount of the object to be heated is larger than a standard amount, and increasing information by the increasing setting section. Is not set, the magnetron is driven on the basis of heating conditions such as the operation time and microwave output for the standard amount of the object to be heated, and if the amount increase information is set by the amount setting unit, the standard amount of Microwave heating, wherein the heating conditions for the heating object are changed so as to increase the microwave output while keeping the operation time as it is, and the microcomputer drives the magnetron based on the changed heating conditions. apparatus. 5. When the change value of the microwave output based on the increase information exceeds the maximum microwave output that can be output by the magnetron, the change value of the microwave output is suppressed within the maximum microwave output, and The microwave heating device according to claim 4, wherein the operation time is increased by an amount corresponding to the suppressed wave output. 6. When the change value of the microwave output based on the increase information exceeds the maximum microwave output that can be output by the magnetron, the change value of the microwave output is suppressed to the maximum microwave output, and The microwave heating device according to claim 4, wherein the operation time is increased by an amount corresponding to the suppressed output.