JPH06260276A - High frequency heating device - Google Patents

Abstract

PURPOSE:To perform a cooking with good make regardless of kinds of foods of a wide range by providing a surface wave heating method and a heating element for absorbing high frequency waves. CONSTITUTION:A high frequency wave from a magnetron 2 of an oscillating source is supplied to a heating chamber 1 through upper and lower waveguides 4, 5. In the chamber 1, synchronous structure heating plates 7, 8 having variable mechanisms 9, 10 for heating strength and generating a surface wave heating mode are mounted on the lower and upper parts, and heating elements 16, 17 for absorbing the high frequency wave to generate heat are provided through heat resisting materials 14, 15 for covering the respective surfaces. A food 6 is placed on the heating element 16, and a control means 19 receives the signal of a temperature sensor 18 for detecting the temperature of the food 6 and controls the magnetron 2 and the mechanisms 9, 10. Thus, general heating, warming, and high temperature heating cooking can be performed without anxiety of uneven heating.

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 food.

[0002]

2. Description of the Related Art A conventional high-frequency heating device radiates a high frequency from a high-frequency oscillation source 2 by power from a commercial power source 3 into a closed space in which a whole heating chamber 1 is surrounded by metal as shown in FIG. The food 6 is being heated. Therefore, the food 6 is placed in the heating chamber 1 in the standing wave mode 22 generated by the wall of the heating chamber.
Was heating up. Further, the food 6 is taken in and out of the heating chamber 1, and in order to confirm the heating condition of the food, the door 6 (not shown) is provided with punching holes so that high frequency does not leak outside. Then, the turntable 23 is provided in order to improve the heat distribution of the food 6 in the heating chamber. Thus, the food 6 was heated from the inside by high frequency vibration. Further, in order to automate the warming of the food 6, the gas such as vapor generated from the food is detected by the detection means 24 and the like, and the control means 19 controls the oscillation source 2 and the like.

On the other hand, in addition to such a standing wave mode heating method, there is a heating method in which the electric field is concentrated near the food by surface wave heating (for example, Japanese Patent Publication No. 47-3877).
No. 8).

[0004]

However, the above-mentioned FIG.
However, even if the distribution in the heating chamber 1 is improved by the turntable, unevenness occurs due to the standing waves in the heating chamber 1, resulting in dissatisfaction with the finished product. For example,
The upper part of the liquid such as milk and liquor can was warmed up, and there was a problem in the workmanship. Further, the detecting means 24 used for automating the warming of the food 6 is 100 ° C. at which the food 6 boils.
In order to detect gases such as steam that exceeds the limit, the automation of milk (beverage temperature 65 ℃) and sake can (40 ℃) that are detected before boiling is performed at an appropriate time setting, and the difference in environmental conditions It was impossible to accurately control the target temperature by using such as.

Further, in the method of using the surface wave, when the electric field is concentrated in the vicinity of the food, there is a limit to the temperature rise, and depending on the food, there is a problem that heating is insufficient. Sometimes the surface was overheated and the opposite food surface was underheated.

SUMMARY OF THE INVENTION The first object of the present invention is to provide a high frequency heating apparatus which solves the above-mentioned problems and which can uniformly control the temperature of food by heating the whole food uniformly by the surface wave heating method. A second object is to provide a high-frequency heating device capable of high-temperature heating and cooking, and a third object is to provide a high-frequency heating device capable of uniformly heating the entire surface of food.

[0007]

In order to solve the above problems, the present invention provides an oscillation source for oscillating a high frequency by a power source,
Periodic structure heating plate that heats high frequency in the surface wave propagation mode arranged vertically through multiple waveguides, heat-resistant material that covers the periodic structure heating plate, and heat that generates heat by contacting the heat-resistant material and absorbing high frequency Body, a driving body for moving the heating element up and down in the heating chamber, or a switching means for switching high frequency power supplied to the upper and lower periodic structure heating plates, and a surface wave propagation mode of the periodic structure heating plate depending on the type of food. It comprises a variable mechanism for changing the intensity, a detecting means for detecting the temperature of food on the periodic structure heating plate, and a control means for controlling the output of the oscillation source by the signal of the detecting means.

Further, an oscillation source for oscillating a high frequency, a periodic structure heating plate for heating the high frequency in a surface wave propagating mode arranged vertically through a plurality of waveguides, and a heat-resistant material for covering the periodic structure heating plate. A plurality of heating elements that come into contact with the heat resistant material and absorb high frequency to generate heat; a driving body that allows the heating elements to move up and down in the heating chamber; and a surface of the periodic structure heating plate depending on the type of food. It comprises a variable mechanism for changing the intensity of the wave propagation mode, a detection means for detecting the temperature of the food on the periodic structure heating plate, and a control means for controlling the output of the oscillation source by the signal of the detection means.

Further, an oscillation source for emitting a high frequency wave, a periodic structure heating plate for heating the high frequency wave in a surface wave propagation mode arranged vertically through a plurality of waveguides, and a heat-resistant material for covering the periodic structure heating plate. A plurality of heating elements that come into contact with the heat resistant material and absorb high frequency to generate heat; a driving body that allows the heating elements to move up and down in the heating chamber; and surface wave propagation of the heating plate depending on the type of food. A variable mechanism for changing the intensity of the mode, and a switching means for switching the high frequency power supplied to the upper and lower periodic structure heating plates,
It comprises a detection means for detecting the temperature of the food on the heating plate and a control means for controlling the output of the transmission source by the signal of the detection means.

[0010]

According to the present invention, with the above-described structure, the heating element that absorbs the high frequency waves of the upper and lower periodic structure heating plates and generates heat is heated to a high temperature due to the electric field concentration of the surface wave, and the food is heated from above and below. Also, by a variable mechanism that changes the electric field concentration on the food or the heating element, it controls the various heating temperatures, and supplies a high frequency to either one of the upper and lower periodic structure heating plates depending on the type of food, It has the function of forming an optimum heating mode, and further has the function of accurately detecting the temperature of food on the periodic structure heating plate.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, 1 is a heating chamber, 2 is a magnetron which is a high frequency oscillation source, 3 is a power source for supplying to the magnetron, 4 and 5 are a plurality of waveguides for supplying the high frequency from the magnetron 2, and 6 is Food, 7 is a periodic structure heating plate below the periodic structure that causes the surface wave heating mode, 8
Is a heating plate above the periodic structure for generating the surface wave heating mode, 9 and 10 are variable mechanisms for changing the intensity of the upper and lower surface wave heating, and 11 and 12 are periodic structure heating plates 7 and 8.
Antenna for exciting high frequency wave from the waveguide
3 is a cooling fan for cooling the magnetron 2, 14 and 15
Is a heat-resistant material that covers the periodic structure, 16, 1
Reference numeral 7 is a heating element that absorbs a high frequency and generates heat on the upper surface of the heat-resistant material, and 18 is a temperature sensor that is a detection unit that detects the temperature of the food 6 on the periodic structure heating plate 7.
Receives the signal from the temperature sensor 18, the magnetron 2,
It is a control means for controlling the variable mechanisms 9 and 10.

2 and 3 are explanatory views of a periodic structure for explaining surface wave heating. Surface wave heating utilizes total reflection of radio waves, and by forming a periodic structure having grooves as shown in FIG. 2, radio waves can be concentrated near the surface. FIG. 3 is an equivalent circuit thereof, in which the characteristic impedance is Z ₀ , the lumped impedance is Z ₁ , the phase constants of the respective spaces are β ₀ and β _p , the phase constant in the Z direction is β _z , and the periodic pitch thereof. Where _p is p, the characteristic equation at that time is cosβ _z p = cosβ ₀ p + (Z ₁ / 2Z ₀ ) · sinβ _p .

In the grooved structure shown in FIG. 2, if the groove depth a and the pitch p are properly selected with respect to the wavelength λ of the operating frequency, the radio waves traveling at right angles to the transmission direction Z are due to the grooves. Since the electric field is concentrated in the vicinity of the groove by being completely reflected by the boundary surface between the groove surface and the free space in the cutoff region, Z
Propagate only in the direction. In addition, the propagation of radio waves in the X direction decreases exponentially (Froquet's theorem, Modern Science Co., Ltd., Microwave Engineering, P.462 to P.464).

Therefore, it is possible to concentrate the electric field on the food by using the periodic structure heating plates 7 and 8 as a periodic structure and providing the variable mechanisms 9 and 10 for changing the depth of the groove.
The exponential decrease of radio waves in the X direction can also be changed. In other words, loosen the degree of concentration in the Z direction,
It is to increase the strength of radio waves in the direction.

Further, depending on the type of food, there are cases where it is necessary to obtain a brown mark such as toast, a temperature rise is desired within a certain period of time, or high temperature cooking is required.
In this case, as shown in FIG. 1, by providing heating elements 16 and 17 on the heat-resistant material 11 to absorb high frequency waves and generate heat, electric field energy due to surface waves is consumed by the heating elements and heat is generated at a high temperature. Depending on the item, it is possible to cook it on both sides (eg steak or bread).

In the above structure, if the depth of the groove is increased, the concentration of radio waves increases near the surface of the groove. Therefore, the adjustment of the meat burning condition and the temperature control is performed by making the groove deeper or shallower. It suffices to adjust the variable mechanism. At this time, the control means 19 controls the variable mechanisms 9 and 10 based on the signal of the temperature sensor 18 as a signal means.

With this surface wave heating method and the constitution of the heating element, the electric field can be freely controlled and a uniform temperature distribution is achieved on the heating element, so that heating unevenness of the food does not occur.

FIG. 4 shows another embodiment of the present invention in which the heating elements 16 and 17 are movable up and down by the driving body 20. With this configuration, in the case of general warming, the heating element can be moved upward and the heating element heated at high temperature can be brought into contact with food.

With this configuration, surface wave heating and combined heating of the heating element 12 are also possible, and the meat can be browned in a short time.

FIG. 5 is also another embodiment of the present invention in which the switching means 21 for switching the high frequency is provided in the waveguides 4 and 5. With this configuration, high frequency power can be supplied to either one of the upper and lower heating plates 7 and 8. Therefore, in the case of warming milk or a can of sake, the control means 19 controls so that the switching means 21 is supplied to the periodic structure heating plate 7, and the method of heating from below is adopted. In this way, since the food is warmed from below, uneven heating does not occur due to convection inside the liquid.

Further, according to the structure of the present invention, the food 6 on the periodic structure heating plate 7 is heated, and the temperature sensor 18 is arranged in contact with the food 6 on the periodic structure heating plate. Detects the temperature rise of the periodic structure heating plate 7 and detects the temperature of the food 6. The temperature rise and the food temperature are correlated with each other with a certain time delay, and when the temperature reaches a desired temperature, the control means 19 automatically stops the oscillation of the magnetron 2.

In the embodiment of the present invention, the detecting means 18 is arranged so as to be in contact with the periodic structure heating plate 7, but it may be detected at a position separated from the periodic structure heating plate 7 by a heat transfer body. It is not limited to the example.

[0024]

As described above, the high frequency heating apparatus of the present invention has the following effects.

(1) A heating mechanism for absorbing high frequency and generating heat is arranged above and below, and a variable mechanism for changing the intensity of the surface wave propagation mode of the periodic structure heating plate is used for general heating, warming,
Even in high-temperature cooking, there is no need to worry about uneven heating of food.

(2) The temperature of the food can be accurately detected by the detecting means for detecting the temperature of the food, which is very useful, and the driving unit for driving the heating element properly selects the heating mode depending on the food. By (warming and browning) and adjusting the position of the driving body, combined heating of the heating element and surface wave heating becomes possible, and food can be heated in a short time.

(3) Since the power can be concentratedly supplied to either one of the periodic structure heating plates by the switching means of the high frequency power in the waveguide, the optimum heating mode is automatically performed according to the type of food. be able to.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a high-frequency heating device according to an embodiment of the present invention.

FIG. 2 is a diagram of a periodic structure explaining the surface wave heating.

FIG. 3 is an equivalent circuit diagram of a periodic structure for explaining the same surface wave heating.

FIG. 4 is an overall configuration diagram of a high-frequency heating device according to another embodiment of the present invention.

FIG. 5 is an overall configuration diagram of a high-frequency heating device according to another embodiment of the present invention.

FIG. 6 is a block diagram of a conventional high-frequency heating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 heating 2 (high frequency) oscillation source 4, 5 waveguide 6 food 7, 8 periodic structure heating plate 9, 10 variable mechanism 14, 15 heat resistant material 16, 17 heating element 18 detection means 19 control means 20 driver 21 Switching means

Claims (3)

[Claims] 1. An oscillation source that oscillates a high frequency, a periodic structure heating plate that heats the high frequency in a surface wave propagation mode arranged vertically through a plurality of waveguides, and a heat-resistant material that covers the periodic structure heating plate. A heating element that comes into contact with the heat resistant material and absorbs high frequency to generate heat; a variable mechanism that changes the intensity of the surface wave propagation mode of the periodic structure heating plate depending on the type of food; and the temperature of the food on the periodic structure heating plate. A high-frequency heating device comprising: a detection unit for detecting the output of the oscillation source; and a control unit for controlling the output of the oscillation source according to a signal from the detection unit. 2. An oscillating source for oscillating a high frequency, a periodic structure heating plate for heating the high frequency in a surface wave propagation mode arranged vertically through a plurality of waveguides, and a heat-resistant material for covering the periodic structure heating plate. A plurality of heating elements that come into contact with the heat resistant material and absorb high frequency to generate heat; a driving body that allows the heating elements to move up and down in the heating chamber; and a surface of the periodic structure heating plate depending on the type of food. A high frequency heating device comprising a variable mechanism for changing the intensity of a wave propagation mode, a detection means for detecting the temperature of food on the periodic structure heating plate, and a control means for controlling the output of the oscillation source by a signal of the detection means. 3. An oscillation source that oscillates a high frequency, a periodic structure heating plate that heats the high frequency in a surface wave propagation mode that is arranged vertically through a plurality of waveguides, and a heat resistant material that covers the heating plate. A plurality of heating elements that come into contact with the heat-resistant material and absorb high frequency to generate heat, a driving element that allows the heating elements to move up and down in the heating chamber, and a surface wave propagation mode of the heating plate depending on the type of food. A variable mechanism for changing the intensity, a switching means for switching the high frequency power supplied to the upper and lower periodic structure heating plates, a detecting means for detecting the temperature of the food on the periodic structure heating plate, and the oscillation by the signal of the detecting means. A high frequency heating device comprising a control means for controlling the output of the source.