JP2002359066A - High frequency heater system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency heater system for uniformly heating food by controlling the output of a high frequency generating means depending on the food. SOLUTION: This high frequency heater system 1 internally stores the high frequency generating means 2, a control device 3 for controlling the operation of the high frequency generating means 2, and a specific dielectric constant detecting means 4. The specific dielectric constant detecting means 4 detects the specific dielectric constant of the food 6. The control means 3 controls the output of the high frequency generating means 2 in proportion to the detected specific dielectric constant.

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 such as a microwave oven for generating high-frequency waves and heating an object to be heated such as food.

[0002]

2. Description of the Related Art An advantage of heating food with a microwave oven, which is a high-frequency heating device, is that the food is heated in an extremely short time as compared with other heating devices. This is because microwave heating causes the water inside the food to vibrate due to high frequency,
This is because it is internal heating that becomes heat. However, a phenomenon called uneven heating often occurred because a portion where the high frequency was concentrated became abnormally hot because of the warming in a short time. The unevenness of the heating varied depending on the food.

[0003] Conventionally, when a frozen food is thawed and heated in a microwave oven, the surface of the food is hot enough to be steamed, while a frozen portion remains in the center or the surface is conversely frozen. The center could be very hot while it was frozen. This is because, when the food temperature is around 0 ° C. and the melted portion and the unmelted portion are mixed, the microwave concentrates on the melted portion and only that portion becomes hot.

[0004]

As described above, the conventional heating method using a microwave oven cannot prevent uneven heating of food and uneven thawing of frozen food.

In view of the above problems, the present invention automatically controls the output of a magnetron, which is a high-frequency generating means, according to all foods when heating the foods with a high-frequency heating device, so that the foods can be uniformly processed in the shortest time. The purpose is to warm.

[0006]

In order to solve the above-mentioned problems, the present invention provides a heating chamber for accommodating an object to be heated, high-frequency generating means for generating a high-frequency wave radiated into the heating chamber, A high-frequency heating apparatus comprising a control unit for controlling an output of the high-frequency generation unit in proportion to a dielectric constant or a relative dielectric constant.

Further, the present invention is characterized in that it has a permittivity detecting means for detecting the permittivity of the object to be heated or the permittivity.

In the present invention, the relative dielectric constant of the object to be heated is 10 to
The control means controls the output of the high-frequency generation means to be 0 to 300 W while changing at a width of 80.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) First, the relationship between food temperature and dielectric constant will be described.

FIG. 1 shows the relative permittivity of food (temperature 15 ° C.) measured by the present inventors. It can be seen that the relative permittivity varies from 0 to 80 depending on the food. In addition,
The relative permittivity is a numerical value used to express the dielectric properties of a substance. The relative permittivity is the actual permittivity and the permittivity of vacuum ε ₀ = 8.85 × 10 ⁻¹² (F / m). And the ratio of

FIG. 2 shows the relationship between the rate of temperature rise of food (food temperature rise / 1 second) and the relative dielectric constant of food by heating 60 g of food at an output of 600 W using a microwave oven for home use. It is. The temperature rise of the food was an average value of 36 food parts. The arrows in the figure indicate the range of temperature variations at 36 points. As shown in FIG. 2, when the relative dielectric constant of the food is low, the rate of temperature rise of the food is high, but the variation depending on the food part is large. However, it was found that when the relative dielectric constant was high, the rate of temperature rise of the food was slow, but the variation among food parts was small. FIG. 2 shows an example of heating at 600 W this time.
Temperature variations are reduced. Conversely, it is known that the higher the output, the faster the temperature rise rate and the greater the temperature variation. FIG. 3 is a schematic configuration diagram of the high-frequency heating device according to the first embodiment of the present invention, and FIG. 4 is a diagram illustrating a relationship between the relative dielectric constant of food and an optimum output of the high-frequency generator.

In FIG. 3, the high-frequency heating device 1 includes a high-frequency generator 2, a controller 3 for controlling the operation of the high-frequency generator 2, and a relative permittivity detector 4 for detecting the relative permittivity of food. And a start switch 5 for instructing the start of cooking is provided. Reference numeral 6 denotes a food to be heated.

Next, the operation of the high-frequency heating device 1 will be described. First, when the food 6 is put into the high-frequency heating device 1 and the start switch 5 is turned on, the relative permittivity detecting means 4 detects the relative permittivity of the food 6. And the high frequency generating means 2
Is controlled by the control device 3 as shown in FIG. 4 in proportion to the detected relative permittivity.

For example, in the case of bread, which has a low relative dielectric constant of about 3 and a high temperature rising rate, the temperature of which is likely to rise partially, the output of the high frequency generator 2 is reduced to about 230 W. As a result, it takes a long time for heating because the output is small, but temperature variation can be reduced. Conversely, the output of the high-frequency generator 2 is set to 880 W for a radish having a high relative dielectric constant of about 68 and a slow heating rate. As a result, the temperature variation tends to be larger than the 600 W heating, but the time required for the heating can be greatly reduced (about 2/3 of the 600 W heating). However, output 88
Equipment below 0 W is heated at maximum output.

Thus, according to the dielectric constant of the food,
By controlling the output of the high-frequency generator, foods with large food temperature variations can be small, and foods that require time can be heated in a short time.

In the above embodiment, the relative permittivity of the food 6 to be heated is detected using the relative permittivity detecting means 4. However, the present invention is not limited to this. It is apparent that the same control can be performed even if the dielectric constant of the food 6 is detected by using the same, and the same effect can be obtained.

(Embodiment 2) FIG. 5 shows a change in the relative dielectric constant of bread, rice and hamburger according to the temperature. As shown in FIG. When the temperature was 10 or less, the temperature rapidly increased near 0 ° C., and at 0 ° C. or more, each value hardly changed. Similar changes were observed in other foods. This is because the water in the food is solid when the temperature is 0 ° C. or less and the water molecules cannot move, but when the water melts at 0 ° C. and becomes liquid, the water molecules can move.

However, the relative dielectric constant of a food having a low moisture content such as bread has a relative dielectric constant of about 3 even at 0 ° C. or higher, so that the relative dielectric constant hardly changes with temperature.

FIG. 6 shows changes in the relative permittivity and temperature of food during cooking, and the output of the high frequency generator.

The operation of the high-frequency heating apparatus shown in FIG. 3 when thawing and heating frozen food such as frozen rice will be described.

First, when the frozen food is put into the high-frequency heating device 1 and the start switch 5 is turned on, the relative permittivity of the frozen food detected by the relative permittivity detecting means 4 indicates a value in the range of 0-10. Then, the control device 3 causes the high frequency generation means 2 to output. At this time, since the relative dielectric constant is small, the output of the high-frequency generation means 2 is set as low as 150 W. When the thawing of the frozen food proceeds and the temperature of the frozen food reaches 0 ° C., the relative permittivity of the frozen food detected by the relative permittivity detecting means 4 starts to rapidly increase. The rise range is 0 to 8 as shown in FIG.
0 depends on the food. At this time, the control device 3 keeps the output of the high-frequency generation means 2 low, although the relative permittivity may be 10 or more in some cases.

When the temperature of the whole food becomes 0 ° C. or higher, the relative permittivity detected by the relative permittivity detecting means 4 indicates a value peculiar to the food. The output of the high frequency generator 2 is set as high as 700 W in accordance with the above.

As described above, when the food temperature is around 0 ° C. and the moisture in the food is a mixture of solids and liquids, the output of the high-frequency generator is stopped or lowered to completely remove the moisture. By increasing the output of the high-frequency generating means after the liquid has become liquid, the whole can be uniformly melted and then heated.

[0025]

As described above, the food can be uniformly heated by controlling the output of the high-frequency generator in the high-frequency heating device according to the dielectric constant or relative dielectric constant of the food.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relative dielectric constant of food at a temperature of 15 ° C.

FIG. 2 is a diagram showing the relationship between the relative dielectric constant of food and the rate of temperature rise of food.

FIG. 3 is a schematic configuration diagram of a high-frequency heating device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing the relationship between the relative permittivity of food and the optimum output of the high frequency generator.

FIG. 5 is a diagram showing a change in relative dielectric constant of bread, rice and hamburger according to temperature.

FIG. 6 is a diagram showing a change in relative dielectric constant and temperature of food during cooking and an output of a high frequency generator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 high frequency heating device 2 high frequency generating means 3 control device 4 relative permittivity detecting means 5 start switch 6 food

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K086 AA01 BA08 CA20 CB01 CC02 CD04 CD11 DA02 3L086 AA01 CB01 CC12 DA12

Claims (3)

[Claims] A heating chamber for accommodating an object to be heated; a high frequency generating means for generating a high frequency radiated into the heating chamber; and a high frequency generating means in proportion to a dielectric constant or a relative dielectric constant of the object to be heated. A high-frequency heating device comprising control means for controlling output. 2. The apparatus according to claim 1, further comprising a permittivity detecting means for detecting a permittivity or a permittivity of the object to be heated.
The high-frequency heating device as described. 3. The controller controls the output of the high-frequency generator to 0 to 300 while the relative permittivity of the object to be heated changes in a range of 10 to 80.
The high-frequency heating device according to claim 1, wherein the high-frequency heating device is controlled to W.