JP3012958B2 - High frequency heating equipment - Google Patents

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 apparatus for heating an object to be heated such as food by applying an electromagnetic wave.

[0002]

2. Description of the Related Art In recent years, various measures have been taken to shorten the heating time in microwave ovens that 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, by generating a maximum output larger than the normal continuous maximum output, it is possible to shorten the heating time while ensuring the safety of each element. Are known.

However, in general households, due to indoor wiring,
Often used with 100V15A rated power supply,
It is necessary to suppress power consumption to 1.5 kW or less.

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

FIG. 7 shows the time t on the horizontal axis and the power consumption W on the vertical axis, and FIG. 7A shows the power consumption of the whole microwave oven. Similarly, FIG. 7B shows electric power W ₁ consumed for radio wave oscillation from a magnetron which is a radio wave radiating part in a microwave oven, and FIG. 7C shows other electric power consumption, for example, cooling means such as a fan or the like. lamp is a power consumption W ₂ such as food placing means, such as a lighting means and the turn table and the like. Although the power consumption W ₂ shown in FIG. 7 (c) is substantially constant regardless of the time, the power W ₁ consumed for radio oscillation shown in FIG. 7 (b) slightly varies with temperature and control method of the magnetron I do. In this case, the heating gradually decreases from 0 to t ₆ and becomes constant after t ₆ . FIG. 7A shows the power consumption of the entire microwave oven, which is W ₁ + W ₂ . Here, in the case of a general household microwave oven, 100V1
A power supply rated at 5 A is often used to suppress power consumption to 1.5 kW or less. Of these, about 10 W or less of a fan 10 W, a lamp 30 W, and a turntable are consumed for purposes other than radio wave oscillation. Further, regarding the radio wave oscillation, since it is converted into a radio wave with an efficiency of about 50 to 60% of the actual power consumption, the high frequency output for heating the food is 500 W
The mainstream is ~ 700W.

[0006]

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

On the other hand, if cooling means such as a fan is removed in order to secure a large amount of electric power for radio wave oscillation, there is a problem that reliability is impaired such as breakage of a radio wave radiating portion such as a magnetron due to a rise in temperature. When the lighting means is removed, there is a problem that the degree of heating cannot be seen from the outside, and when the food placing means such as a turntable is removed, there is a problem that the food is not heated uniformly and the finish of cooking becomes uneven.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and a high-frequency heating apparatus capable of confirming the progress of food heating and uniform heating of food without shortening the heating time, without being damaged by a temperature rise of a magnetron or the like. It is intended to realize.

[0009]

In order to achieve the above object, a high-frequency heating apparatus according to the present invention has a heating chamber for taking in and out an object to be heated such as food, a radio wave radiating section for radiating electromagnetic waves into the heating chamber, A cooling unit that cools the radio wave radiating unit, an illuminating unit that irradiates light into the heating chamber, a food placing unit that performs operations such as rotating motion by placing food in the heating chamber, and the radio wave radiating unit. A control unit for controlling the cooling unit, the lighting unit, and the food placing unit, switching a high-frequency output of the radio wave radiating unit to a plurality, and when the maximum high-frequency output is performed, the cooling unit, the lighting unit, and the food mounting unit. It is configured to control to stop any operation of the mounting means or to operate with low power.

[0010]

According to the present invention, in the above configuration, the high frequency output of the radio wave radiating section is switched to a plurality, and at the time of the maximum high frequency output, the operation of any of the cooling means, the lighting means, and the food placing means is stopped or the operation is performed with low power. Control so that the power consumption can be efficiently distributed depending on the case.
In addition to heating intensively, it has the function of cooling the radio wave radiating unit when necessary, illuminating 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.
This will be described with reference to FIG.

FIG. 1 is a schematic sectional view of a high-frequency heating apparatus according to a first embodiment of the present invention. As shown in the figure, a food 2 in a heating chamber 1 is heated by a 2.45 GHz radio wave 5 radiated from a magnetron 3 via a waveguide 4. The food 2 is placed on the turntable 6 and driven to rotate by the operation of the drive unit 7 so as to be in a uniform cooking finish state. The magnetron 3 is forcibly air-cooled by the cooling fan 8, and the lamp 9 emits light 11 through the hole 10 into the heating chamber 1 so that the user can see the progress of the cooking. Control unit 1
2 receives a signal 13 corresponding to the temperature rise of the magnetron 3 and a signal 14 corresponding to the food weight, a signal 15 for controlling the output of the magnetron 3, a signal 16 for controlling the lamp 9, and the cooling fan 8. 17 for the control of
And a signal 1 for controlling the drive unit 7 of the turntable 6
8 to control the total power consumption to be efficiently within the rating.

FIG. 2 is an electric circuit diagram of the high-frequency heating device for controlling the magnetron output. As shown in the figure, the rectifier circuit rectifies the power supplied from the commercial power supply 19 into a DC voltage, a rectifier circuit including 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 and high-voltage diodes 28 and 29, a magnetron 3 that receives an output of the high-voltage rectifier circuit to generate 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. The start control unit 32 gives a command to obtain a maximum high-frequency output for a certain time when the high-frequency heating device is started. I have. After that, the control unit 12 lowers the high-frequency output and activates the turntable driving unit 7, the cooling fan 8, and the lamp 9.

FIG. 3 is a characteristic diagram showing a change over time in power consumption, and is an example in which control is performed so as to provide a 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, in FIG. 3 (b) power W ₁ consumed for the radio waves oscillated from the magnetron 3, the heating starts after a predetermined time (0 to t ₁₎ is the power consumption is high in order to generate the maximum high-frequency output , t ₁ thereafter is lower. FIG. 3 (c) Other power consumption is a cooling fan 8, lamps 9 and the power consumption W _2, such as the turntable 6, while 0 to t ₁ so as not to consume power by stopping the operation On the contrary, after t ₁ when the high-frequency output is reduced, constant power is consumed for normal operation. In this embodiment, there is an effect that the control can be simplified because t ₁ is constant.

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 denoted by the same reference numerals.

FIG. 4 is a characteristic diagram showing a change over time in power consumption in the second embodiment of the present invention, and is an example in which the maximum high-frequency output is controlled when the temperature of the magnetron 3 is lower than 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. For a certain time (0 to t ₂ ) after the start of the heating, the power consumption is high to generate the maximum high-frequency output. After ₂ it is low. FIG.
(C) shows 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 is not to consume power by stopping the operation, reduced t ₂ subsequent high-frequency output is reversed consumes constant power in order to operate normally. FIG. 4 (d) shows the time change of the magnetron 3 temperature. The temperature at the start of heating is T ₁ , the upper limit of the temperature at which the reliability can be maintained is T ₃ , and after that, if the cooling fan 8 is rotated, the temperature does not exceed T _3. the limit is caused to the temperature saturated as T _2, the time exceeding T ₂ t ₂
And 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 operation of the cooling fan 8 and the like is started. This stops the rise in temperature. In this embodiment, there is an effect that a high-frequency output can be efficiently supplied in accordance with 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 denoted by the same reference numerals.

FIG. 5 is a characteristic diagram showing a time change of the power consumption in the third embodiment of the present invention, in which the high-frequency output is controlled so as to gradually decrease from the maximum value. FIG.
(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 and a certain time (0 to 0) after the start of the heating.
At t ₃ ), the power consumption is high because the maximum high-frequency output is generated, but it gradually decreases after t ₃ and becomes constant after t ₄ . FIG. 5C shows the other power consumption, which is the power consumption W ₂ of the cooling fan 8, the lamp 9, the turntable 6, and the like.
Although, 0 to t ₃ while is not to consume power by stopping the operation, t ₃ thereafter gradually increases gradually, reduced t ₄ subsequent high-frequency output consumes constant power ing.

FIG. 6 shows a method of determining t ₃ and t ₄ shown in FIG. 5, wherein the horizontal axis represents the food weight m and the vertical axis represents time t. Various methods are considered for determining the optimal heating time based on the information from the food 2 and cooking. As shown in FIG. 1, the optimal heating time t ₅ (m) is determined from the signal 14 corresponding to the food weight m. It is 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, or should the lamp 9 be turned on so that the progress can be seen by the user? The limit is roughly determined. Based on such a limit time, t ₃ and t ₄ are set for each weight. In this embodiment, there is an effect that the user can be more satisfied, such as confirming the quality of the heating and the progress at the end of the heating, and can efficiently supply the high-frequency output.

[0020]

As is apparent from the above description, the high-frequency heating apparatus of the present invention uses lamps, cooling fans, turntables, and the like, and reduces the power unnecessary for radio wave heating as much as possible. It is possible to confirm the progress of the heating of the food and to uniformly heat the food without increasing the heating time and without damaging the magnetron or the like while increasing the heating time.

[Brief description of the drawings]

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

FIG. 2 is an electric circuit diagram of the 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. Characteristic diagram showing

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

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating room 2 Food 3 Magnetron (radio wave radiation part) 6 Turntable (food placement means) 8 Cooling fan (cooling means) 9 Lamp (lighting means) 12 Control part (control means)

Continued on the front page (56) References JP-A-64-12492 (JP, A) JP-A-59-16096 (JP, U) JP-A-56-75608 (JP, U) (58) Fields investigated (Int) .Cl. ⁷ , DB name) H05B 6/68 F24C 7/02

Claims (4)

(57) [Claims] 1. A heating chamber for taking in and out an object to be heated such as food, a radio wave radiating section for radiating an electromagnetic wave into the heating chamber,
A cooling unit that cools the radio wave radiating unit, an illuminating unit that irradiates light into the heating chamber, a food placing unit that places a food in the heating chamber and performs an operation such as a rotary motion, and the radio wave radiating unit Control means for controlling the cooling means, the illuminating means, and the food placing means, switching the high-frequency output of the radio wave radiating unit to a plurality, and when the maximum high-frequency output, the cooling means, the lighting means, the food A high-frequency heating device configured to stop any operation of the mounting means or to control the operation with low power. 2. The high-frequency heating apparatus according to claim 1, wherein a maximum high-frequency output is supplied for a predetermined time after the start of heating. 3. The high-frequency heating apparatus according to claim 1, further comprising a temperature detecting means for detecting a temperature of the radio wave radiating section, and supplying a maximum high-frequency output during a certain temperature or less. 4. A detecting means for detecting a physical quantity (weight, shape, temperature, dielectric constant, etc.) of the food and a state (temperature, humidity, electric field, etc.) in the heating chamber, and according to an output of the detecting means. The high-frequency heating device according to claim 1, wherein the high-frequency heating device is configured to supply a maximum high-frequency output.