JPH06257757A - High frequency heating apparatus - Google Patents

Abstract

PURPOSE:To shorten heating time, prevent any damage from being produced on a food owing to temperature rise of a magnetron, etc., and ensure confirmation of the degree of promotion of food heating and uniform heating of a food. CONSTITUTION:A high frequency output from an electromagnetic radiation part 3 is changed over into a plurality of outputs, and upon a maximum high frequency output operation of any of cooling means 8, illumination means 9, food placement means 6 is interrupted or is operated at lower electric power.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency heating device for heating an object to be heated such as food by applying electromagnetic waves.

[0002]

2. Description of the Related Art In recent years, various efforts have been made to shorten heating time in microwave ovens, which are high-frequency heating devices. For example, as shown in JP-A-2-227988, the temperature around each element such as a magnetron is detected,
Until the detected temperature reaches the safety limit temperature of each element, the maximum output that is larger than the normal continuous maximum output is generated to ensure the safety of each element and shorten the heating time. Are known.

However, in an ordinary household, due to the indoor wiring,
Often used with a 100V15A rated power supply,
It is necessary to keep the power consumption below 1.5 kW.

The power consumption of a microwave oven, which is a general conventional high-frequency heating device, will be described below with reference to FIG.

In FIG. 7, the horizontal axis represents time t and the vertical axis represents power consumption W, and FIG. 7A shows the power consumption of the entire microwave oven. Similarly, FIG. 7B shows electric power W ₁ consumed by the magnetron, which is a radio wave radiating part in the microwave oven, for electric wave oscillation, and FIG. 7C shows other electric power consumption, for example, cooling means such as a fan or the like. It is power consumption W ₂ of lighting means such as a lamp and food placing means such as a turntable. The power consumption W ₂ shown in FIG. 7 (c) is almost constant regardless of time, but the power W ₁ consumed for radio wave oscillation shown in FIG. 7 (b) varies somewhat depending on the temperature of the magnetron and the control method. To do. In this case, it gradually decreases from the start of heating 0 to t ₆ , and becomes constant after t ₆ . Since the power consumption of the entire microwave oven is shown in FIG. 7A, the power is W ₁ + W ₂ . Here, in the case of a general household microwave oven, 100V1
It is often used with a power supply with a rating of 5 A, and the power consumption is suppressed to 1.5 kW or less. Of these, about 10 W of fan, 30 W of lamp, and 10 W or less of turntable are consumed for purposes other than radio wave oscillation. Furthermore, as for radio wave oscillation, it changes to radio wave with an efficiency of about 50-60% relative to the actual power consumption, so the high frequency output for food heating is 500W.
The thing of -700W is the mainstream.

[0006]

However, in the above-mentioned conventional configuration, since the power consumption other than radio wave oscillation is always constant from the start of heating, there is an upper limit to the electric power that can be used for radio wave oscillation, and the heating time is limited. There was a problem that could not be shortened.

On the contrary, if cooling means such as a fan is removed in order to secure a large amount of electric power for radio wave oscillation, a problem such as damage due to a temperature rise of a radio wave emitting part such as a magnetron is lost, and a lamp or the like is generated. There is a problem in that the degree of progress of heating cannot be seen from the outside when the illuminating means is removed, and there is a problem that the food is not uniformly heated and the finish of cooking is uneven when the food placing means such as a turntable is removed.

The present invention is to solve the above-mentioned problems, and a high-frequency heating apparatus that enables confirmation of the progress of food heating and uniform food heating without shortening the heating time and without damage due to temperature rise of the magnetron or the like. The purpose is to realize.

[0009]

In order to achieve the above-mentioned object, a high-frequency heating apparatus of the present invention has a heating chamber for loading and unloading an object to be heated such as food, a radio wave radiating section for radiating electromagnetic waves into the heating chamber, and Cooling means for cooling the radio wave radiating section, illuminating means for irradiating light into the heating chamber, food placing means for placing food in the heating chamber and performing operations such as rotational movement, and the radio wave radiating section. It has the cooling means, the illuminating means, and a control means for controlling the food placing means, switches the high frequency output of the radio wave radiating section to a plurality of frequencies, and at the time of maximum high frequency output, the cooling means, the illuminating means, and the food placing means. Either of the operation of the mounting means is stopped or controlled so as to operate with low electric power.

[0010]

According to the present invention, in the above structure, the high frequency output of the radio wave radiating portion is switched to a plurality of frequencies, and at the time of maximum high frequency output, operation of any one of the cooling means, the lighting means, and the food placing means is stopped or operated with low power. Control so that the power consumption can be distributed efficiently depending on the case.
In addition to performing intensive heating, it has the effects of cooling the radio wave radiation part when necessary, illuminating the inside of the heating chamber, and moving food.

[0011]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
Will be described with reference to.

FIG. 1 is a schematic sectional view of a high frequency heating apparatus showing a first embodiment of the present invention. As shown in the figure, the food 2 in the heating chamber 1 is heated by the radio wave 5 of 2.45 GHz emitted from the magnetron 3 through the waveguide 4. The food 2 is placed on the turntable 6 and is rotationally driven by the operation of the drive unit 7 so that a uniform cooked state is obtained. The magnetron 3 is forcibly air-cooled by the cooling fan 8, and the lamp 9 emits the light 11 into the heating chamber 1 through the hole 10 so that the user can see the progress of cooking. Control unit 1
2 receives a signal 13 according to the temperature rise of the magnetron 3 and a signal 14 according to the food weight, and also has a signal 15 for controlling the output of the magnetron 3, a signal 16 for controlling the lamp 9, and a cooling fan 8. Signal for control of
Or signal 1 for controlling the drive unit 7 of the turntable 6
8 is given to control so that the total power consumption is efficiently kept within the rating.

FIG. 2 is an electric circuit diagram of a high frequency heating device for controlling the output of the magnetron. As shown in the figure, a rectifier circuit that rectifies the electric power supplied from the commercial power source 19 into a DC voltage, an inductor 21, and a capacitor 22, and a capacitor 23, a transistor 24, a diode 25, and a step-up transformer 26. An inverter circuit, a high-voltage rectifier circuit including a high-voltage capacitor 27, high-voltage diodes 28 and 29, a magnetron 3 that receives the output of the high-voltage rectifier circuit and generates a high-frequency output, and a control circuit 30 that controls the operating frequency of the transistor 24,
The control unit 12 controls the relay 31 and gives a heating command to the control circuit 30, and the start control unit 32 gives a command for obtaining a maximum high frequency output for a certain time when the high frequency heating device is activated. There is. Thereafter, the control unit 12 lowers the high frequency output and activates the turntable drive unit 7, the cooling fan 8 and the lamp 9.

FIG. 3 is a characteristic diagram showing the time variation of the power consumption, which is an example of controlling so as to give the maximum high frequency output for a fixed time after the start of heating. FIG. 3A shows the power consumption W ₁ + W ₂ of the entire microwave oven, which is constant regardless of time. Similarly, FIG. 3B shows the power W ₁ consumed for the radio wave oscillation from the magnetron 3, and the power consumption is high because the maximum high frequency output is generated for a certain time (0 to t ₁ ) after the heating is started. , t ₁ thereafter is lower. FIG. 3C shows the other power consumption, which is the power consumption W ₂ of the cooling fan 8, the lamp 9, the turntable 6, etc., but the operation is stopped between 0 and t ₁ so that the power is not consumed. On the contrary, after t ₁ when the high frequency output is reduced, a certain amount of electric power is consumed for normal operation. In this embodiment, the fact that t ₁ is constant has the effect of simplifying the control.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIG. The same components as those described in the first embodiment are designated by the same reference numerals.

FIG. 4 is a characteristic diagram showing the time variation of the power consumption in the second embodiment of the present invention, which is an example in which the maximum high frequency output is controlled when the temperature of the magnetron 3 is below a certain temperature. FIG. 4A shows the power consumption W ₁ + W ₂ of the entire microwave oven, which is constant regardless of time as in FIG. 3A. FIG. 4B shows the power W ₁ consumed for the radio wave oscillation from the magnetron 3, and at a certain time (0 to t ₂ ) after the start of heating, the power consumption is high because the maximum high frequency output is generated. _It is getting lower after ₂ . Figure 4
(C) is other power consumption, such as the cooling fan 8 and the lamp 9.
A power consumption W ₂ such as and turntable 6 but, 0
During t _2, the operation is stopped so that the power is not consumed, and conversely, after t ₂ when the high frequency output is reduced, a certain amount of power is consumed for the normal operation. FIG. 4 (d) shows the time change of the temperature of the magnetron 3. The temperature at the start of heating is T ₁ , the upper limit of the temperature that can maintain reliability is T ₃ , and if the cooling fan 8 is rotated thereafter, it will not exceed T _3. the limit is caused to the temperature saturated as T _2, the time exceeding T ₂ t ₂
I am trying. T ₁ , T ₂ and T ₃ change depending on which part of the magnetron 3 is captured, but when heating progresses and exceeds T ₂ (t ₂ ), the high frequency output is reduced and the cooling fan 8 and other operations start. Therefore, the rise in temperature is stopped. In this embodiment, there is an effect that the high frequency output can be efficiently supplied according to the reliability of the magnetron 3.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to FIGS. The same components as those described in the first embodiment are designated by the same reference numerals.

FIG. 5 is a characteristic diagram showing the time change of the power consumption in the third embodiment of the present invention, which is an example in which the high frequency output is controlled to be gradually decreased from the maximum value. Figure 5
(A) represents the power consumption W ₁ + W ₂ of the entire microwave oven, which is constant regardless of time as in FIGS. 3 (a) and 4 (a). FIG. 5B shows the electric power W ₁ consumed for the radio wave oscillation from the magnetron 3 for a certain time (0 to
Although power consumption is high at t ₃ ) since the maximum high frequency output is generated, it gradually decreases after t ₃ and remains constant after t ₄ . FIG. 5C shows the other power consumption, that is, the power consumption W ₂ of the cooling fan 8, the lamp 9, the turntable 6, and the like.
However, from 0 to t _3, the operation is stopped so that power is not consumed. After t ₃ , the power gradually increases, and after t ₄ when the high frequency output decreases, a constant power is consumed. ing.

FIG. 6 shows a method of determining t ₃ and t ₄ shown in FIG. 5, in which the horizontal axis indicates the food weight m and the vertical axis indicates the time t. There are various methods for cooking by determining the optimum heating time based on the information from the food 2, but as shown in FIG. 1, the optimum heating time t ₅ (m) is calculated from the signal 14 corresponding to the food weight m. It is also possible to decide. At this time, in order to obtain a uniform finish at the end of cooking, when should the turntable 6 be turned, and whether the lamp 9 should be turned on so that the progress can be seen by the user. The limit is decided. Based on such limit times, t ₃ and t ₄ are set for each weight. In this embodiment, there is an effect that it is possible to more satisfy the user such as the quality at the end of heating and the confirmation of the progress, and to efficiently supply the high frequency output.

[0020]

As is clear from the above description, the high-frequency heating apparatus of the present invention uses a lamp, a cooling fan, a turntable, etc., while reducing unnecessary electric power for electric wave heating as much as possible. It is possible to confirm the degree of progress of food heating and to uniformly heat food without increasing the heating time and without damaging the magnetron or the like while increasing the heating time.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a high frequency heating apparatus according to a first embodiment of the present invention.

FIG. 2 is an electric circuit diagram of the same high-frequency heating device.

3A is a characteristic diagram showing the total power consumption of the high-frequency heating device, FIG. 3B is a characteristic diagram showing the power consumption for radio wave oscillation, and FIG. 3C is the power consumption other than radio wave oscillation. Characteristic diagram showing

FIG. 4A is a characteristic diagram showing the total power consumption of the high-frequency heating apparatus according to the second embodiment of the present invention, FIG. 4B is the same as the characteristic diagram showing the power consumption for radio wave oscillation, and FIG. , A characteristic diagram showing power consumption other than radio wave oscillation (d) is a characteristic diagram showing temporal change of magnetron temperature

5A is a characteristic diagram showing the total power consumption of the high-frequency heating apparatus according to the third embodiment of the present invention, FIG. 5B is the same as the characteristic diagram showing the power consumption for radio wave oscillation, and FIG. , Characteristic chart showing power consumption other than radio wave oscillation

FIG. 6 is a weight-time characteristic diagram of the same high-frequency heating device.

FIG. 7A is a characteristic diagram showing the total power consumption of a conventional high-frequency heating apparatus, FIG. 7B is a characteristic diagram showing the power consumption for radio wave oscillation, and FIG. 7C is a characteristic diagram showing the power consumption other than radio wave oscillation. Characteristic diagram showing power

[Explanation of symbols]

 1 Heating Room 2 Food 3 Magnetron (Radio Wave Emitting Section) 6 Turntable (Food Placement Means) 8 Cooling Fan (Cooling Means) 9 Lamp (Lighting Means) 12 Control Part (Control Means)

Claims (4)

[Claims] 1. A heating chamber for loading and unloading an object to be heated such as food, and a radio wave radiating section for radiating electromagnetic waves into the heating chamber.
Cooling means for cooling the radio wave radiating part, illuminating means for irradiating light into the heating chamber, food placing means for placing food in the heating chamber and performing operations such as rotational movement, and the radio wave radiating part And a cooling means, the lighting means, and a control means for controlling the food placing means, switching the high frequency output of the radio wave radiating part to a plurality, at the time of maximum high frequency output the cooling means, the lighting means, the food A high-frequency heating device configured to stop operation of any one of the mounting means or to operate with a low electric power. 2. The high-frequency heating device according to claim 1, wherein the maximum high-frequency output is supplied for a certain period of time after the start of heating. 3. The high-frequency heating apparatus according to claim 1, further comprising a temperature detecting means for detecting the temperature of the radio wave radiating portion, and supplying the maximum high-frequency output while the temperature is below a certain temperature. 4. A detection means for detecting the physical quantity of food (weight, shape, temperature, dielectric constant, etc.) and the state of the heating chamber (temperature, humidity, electric field, etc.), and according to the output of the detection means. The high frequency heating apparatus according to claim 1, wherein the maximum high frequency output is supplied.