JP7203301B2 - High frequency heating device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high-frequency heating device having a defrosting function.

Conventionally, this type of high-frequency heating device detects the reflected power, which varies depending on the food type, shape, temperature, etc., with an antenna, detects it with a detection circuit, and then controls the operation of various devices according to the output taken into the controller. There existed (see Patent Literature 1).

In addition, reference temperature detection means for measuring the temperature at a predetermined position other than the position where the food is placed, infrared detection means for detecting and thermoelectrically converting radiant heat radiated from the food or a predetermined position without contact, and Food temperature calculation means for calculating the food temperature from the output of the infrared detection means, the output of the infrared detection means due to radiant heat from a predetermined position, and the output of the reference temperature detection means, and control for controlling the heating means according to the output of the food temperature calculation means and switching means for driving the infrared detection means and switching the direction of radiant heat detected by the infrared detection means between the direction of food and the direction of a predetermined position (see Patent Document 2).

Furthermore, a weight sensor that detects the weight of the food, a microwave detection sensor that detects the amount of high-frequency energy reflected from the food in the heating chamber, and output signals from the weight sensor and the microwave detection sensor determine the heating time of the food and the magnetron. There has been a high-frequency heating apparatus consisting of a control means for controlling the high-frequency output of (see Patent Document 3).

JP-A-3-95317 Japanese Patent No. 3491302 JP-A-4-65095

However, conventionally, when using a high-frequency heater represented by a microwave oven, there has been a problem of unevenness in the performance represented by uneven heating of each part of the object to be heated. In order to solve this problem, various sensors are installed to detect the heating state of the object to be heated, and the detection results are fed back to the heating means to control the output of the heating means such as magnetrons and radiation heaters, thereby eliminating uneven heating. I've been trying to prevent

For example, in Patent Literature 1, a detection circuit detects reflected power that varies depending on the type, shape, temperature, etc. of the food, and controls the heating means. Patent document 2 uses an infrared detection means (infrared sensor), detects the infrared rays of the object to be heated, detects the temperature of the heated part, and controls the heating means. Patent document 3 controls the heating time of food and the high-frequency output of a magnetron based on the output signals of a microwave detection sensor that detects the amount of reflected high-frequency energy and a weight sensor.

However, each sensor alone cannot completely prevent uneven heating. The detection sensor can measure incident waves from the heating means to the heating chamber and reflected waves from the heating chamber to the heating means. Although the detection is better, the temperature change on the lower surface of the object to be heated cannot be detected with high precision compared to the temperature change on the upper surface.

Further, if the infrared sensor is installed above the heating chamber, it can detect almost only the temperature change of the upper surface of the object to be heated. Also, with a weight sensor, it is very difficult to detect uneven heating in the first place.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high-frequency heating apparatus that combines a plurality of types of sensors to reduce uneven heating.

In order to solve the above conventional problems, the high-frequency heating apparatus of the present invention includes a heating chamber containing an object to be heated, and a high-frequency wave radiating into the heating chamber from an entrance at the bottom of the heating chamber to heat the object to be heated. A radio wave radiating part for heating, an antenna for detecting high frequencies in the heating chamber, a detecting means for detecting the high frequencies detected by the antenna, and a device installed above the heating chamber to be heated from the infrared rays detected in the heating chamber. an infrared sensor for estimating the temperature of an object; and control means for controlling the output of the radio wave radiating section based on the output of the detection means and the output of the infrared sensor, wherein the control means outputs the output of the detection means. and the temperature of the upper surface of the object to be heated is estimated by the output of the infrared sensor, and the output of the radio wave emitting unit is controlled.

It is possible to provide a high-frequency heating apparatus with less uneven heating of an object to be heated.

Schematic diagram of the high-frequency heating device according to Embodiment 1 Schematic diagram of the detection circuit in Embodiment 1 Schematic diagram of a high-frequency heating device according to Embodiment 2

A first invention comprises a heating chamber for housing an object to be heated, a radio wave radiating section for radiating high frequency waves into the heating chamber from an entrance at the bottom of the heating chamber to heat the object to be heated, and a high frequency wave in the heating chamber. a detection means for detecting the high frequency detected by the antenna; an infrared sensor installed in the upper part of the heating chamber for estimating the temperature of the object to be heated from the infrared rays detected in the heating chamber; control means for controlling the output of the radio wave radiating section based on the output of the means and the output of the infrared sensor, the control means estimating the temperature of the lower surface of the object to be heated from the output of the detection means; and estimating the temperature of the upper surface of the object to be heated from the output of the infrared sensor, and controlling the output of the radio wave radiating section.

As a result, heating unevenness and temperature difference of the object to be heated can be reduced as much as possible, and a desired finished heating effect can be obtained.

A second aspect of the present invention includes a second entrance at the top of the heating chamber, and a second radio wave radiating section that radiates high frequency waves from the second entrance into the heating chamber to heat an object to be heated. The control means estimates the temperature of the lower surface of the object to be heated from the output of the detection means, estimates the temperature of the upper surface of the object to be heated from the output of the infrared sensor, and estimates the temperature of the upper surface of the object to be heated. It is characterized by controlling the output of the second radio wave radiating section.

As a result, it is possible to further reduce uneven heating and temperature difference of the object to be heated, and obtain a desired finished heating effect.

In a third invention, the control means controls the radio wave radiating section so that the temperature of the lower surface of the object to be heated and the temperature of the upper surface of the object to be heated reach substantially the same predetermined temperature, and the temperature reaches the predetermined temperature. After that, the heating of the object to be heated is finished.

As a result, heating unevenness and temperature difference of the object to be heated can be reduced as much as possible, and a desired finished heating effect can be obtained.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited by this embodiment.

(Embodiment 1)
A high-frequency heating apparatus according to Embodiment 1 will be described with reference to FIG. An object to be heated 11 placed and housed on a mounting table 13 in the heating chamber 10 passes through a waveguide 23 from a radio wave emitting portion 20 composed of a magnetron or the like, and from an incident port 12 provided in the lower portion of the heating chamber 10. Heated by radiated radio frequency.

A high frequency wave passing through a waveguide 23 is detected by an antenna 21 called a directional coupler, sent to a detection means 22 via the antenna 21, and detected there. The detecting means 22 can detect radio waves (incident waves) emitted from the radio wave emitting portion 20 and emitted from the inlet 12 to the heating chamber 10 . In addition, the incident wave radiated into the heating chamber 10 may not be absorbed by the object 11 to be heated and part of the radio wave may return to the waveguide 23 . The detecting means 22 can also detect the radio waves (reflected waves) returning to the radio wave emitting section 20 via the radio wave 12 . That is, the detection means 22 is constructed so as to be able to detect the amounts of incident waves and reflected waves.

Normally, the detection means 22 is composed of a circuit as shown in FIG. 2, and the output of the detection means 22 is often voltage. A signal input from the antenna 21 to the detection means 22 passes through the input (terminal) 40 in FIG. 2, is detected, and reaches the output (terminal) 45 . A resistor 41 , a diode 43 , a resistor 42 and a capacitor 44 are connected between the input 40 and the output 45 . A signal is input from this output 45 to the control means 24 in FIG.

Further, the antenna 21 called a directional coupler functions like a signal sensor, and usually detects incident waves with attenuation to some extent (for example, about 20 dB), and also attenuates reflected waves to some extent (about 20 dB). to detect. Each signal is converted to a DC voltage via the detection means 22 and inputted to the control means 24 .

Not only the signal from the detection means 22 but also the signal from the infrared sensor 25 is input to the control means 24 . Here, the infrared sensor 25 is a sensor that detects the temperature of the heating chamber from the intensity of infrared rays.

The infrared sensor 25 uses 8 to 64 elements. In the type with a small number of elements, the infrared sensor 25 is movable, and the temperature of almost the entire upper surface of the object to be heated 11 can be detected in a matrix while the infrared sensor 25 is moved. In addition, since the field of view of the infrared sensor 25 is widened in the type with many elements, it is not necessarily required to be movable, and the temperature of almost the entire upper surface of the object 11 to be heated 11 can be detected in a matrix form by being fixed. Further, by averaging the temperature of each section of the matrix, the average temperature of substantially the entire upper surface of the object 11 to be heated can be measured and estimated.

As far as the temperature of the object 11 to be heated is concerned, the infrared sensor 25 can detect the temperature of the substantially upper surface of the object 11 to be heated, i. 25 is detectable. Since the temperature of the bottom surface of the object 11 to be heated does not reach the infrared sensor 25 , the temperature of the bottom surface of the object 11 to be heated cannot be detected by the infrared sensor 25 . It is practically impossible to know the temperature of the lower surface of the object 11 to be heated using the infrared sensor 25 . This is because the object to be heated 11 is placed on the mounting table 13 or the like and then placed in the heating chamber.

Therefore, the detection means 22 is used to obtain the temperature information of the lower surface of the object 11 to be heated. The entrance 12 of high frequency to the heating chamber 10 is arranged below the mounting table 13 for the object 11 to be heated (under the heating chamber 10), and the high frequency is emitted from the entrance 12 to the object 11 to be heated in the heating chamber 10. The high frequency (incident wave) received from the heating chamber 10, or the high frequency (reflected wave) returning to the waveguide 23 from the heating chamber 10 through the entrance 12, or both the incident wave and the reflected wave are received by the antenna 21, and the detection means 22 By detecting at , approximate temperature information of the lower surface of the object 11 to be heated can be obtained.

For example, when the frozen object to be heated 11 is thawed, if the amount of reflected waves is larger than the amount of incident waves by a certain amount, the lower surface of the object to be heated 11 is still frozen. 11 indicates a state in which radio waves are not completely absorbed. Further, when the frozen object 11 to be heated is thawed, if the amount of reflected waves is smaller than the amount of incident waves by a certain amount, the lower surface of the object 11 to be heated absorbs radio waves, so thawing progresses to a certain extent. Indicates the state of By specifically detecting the amount of the incident wave and the amount of the reflected wave, the degree of thawing of the lower surface of the object 11 to be heated when the frozen object 11 to be heated is thawed, and the extent to which the object to be heated 11 is heated. It becomes possible to roughly estimate the temperature of the lower surface of the object to be heated 11 .

Even if the detection means 22 is used, it is difficult to know the fine temperature distribution of the lower surface of the object 11 to be heated. For the purpose of knowing the temperature difference, much more detailed information can be obtained than using the infrared sensor 25 alone. By detecting the temperature of the upper surface of the object to be heated 11 with the infrared sensor 25 and detecting the temperature of the lower surface of the object to be heated 11 with the detection means 22, the radio wave emitting section 20 can be optimally controlled by the control means 24. .

As an example, while the object to be heated 11 is being heated by the radio wave emitting unit 20, the temperature of each section of the matrix is averaged by the infrared sensor 25 so that the average temperature of almost the entire upper surface of the object to be heated 11 becomes 1. Suppose it was °C. At this time, it is assumed that the temperature information of the lower surface of the object to be heated 11 detected by the detection means 22 is 3°C. Assuming that the target end temperature of the entire object 11 to be heated is 2° C., the control means 24 weakens the output of the radio wave emitting unit 20 and takes time so that the radio waves are absorbed by the entire object 11 to be heated. The output of the radio wave emitting part 20 is controlled so that the temperature of almost the entire upper surface of the object 11 to be heated is raised to 2° C. and the temperature of the lower surface of the object 11 to be heated is lowered to 2° C., and the upper surface of the object 11 to be heated and It is possible to terminate the heating when the temperature of the lower surface reaches 2°C.

In this manner, the radio wave emitting unit 20 is controlled so that the temperature of the lower surface of the object 11 to be heated and the temperature of the upper surface of the object 11 to be heated reach substantially the same predetermined temperature. If the heating is terminated, uneven heating and temperature difference of the object 11 to be heated can be reduced as much as possible, and a desired finished heating effect can be obtained.

(Embodiment 2)
FIG. 3 is a schematic diagram of a high-frequency heating apparatus according to Embodiment 2. FIG. A description of the configuration similar to that of the first embodiment is omitted. A second radio wave radiating portion 26 and a second waveguide 27 are arranged in the high-frequency heating device so that high-frequency waves can be radiated into the heating chamber 10 from the second entrance 14 . is arranged in the upper part of the heating chamber 10 . Accordingly, together with the configuration of Embodiment 1, high frequency waves can be incident into the heating chamber 10 from both the upper surface and the lower surface of the heating chamber 10 .

The control means 24 analyzes the temperature information output from the infrared sensor 25 and the detection means 22, and if it detects that the temperature of either the upper surface or the lower surface of the object 11 to be heated is higher than the other, it is canceled. The radio wave emitting section 20 and/or the second radio wave emitting section 26 can be controlled.

For example, if the temperature of the upper surface of the object 11 to be heated is higher than the temperature of the lower surface during heating of the object 11 to be heated by the radio wave radiating portion 20 and the second radio wave radiating portion 26, the output of the radio wave radiating portion 20 is is increased or the output of the second radio wave radiating section 26 is decreased. On the other hand, if the temperature of the upper surface of the object 11 to be heated is lower than the temperature of the lower surface, the output of the radio wave radiating section 20 is decreased or the output of the second radio wave radiating section 26 is increased. As a result, substantially the entire object to be heated 11 can be heated evenly.

A radiation heater may be used instead of one of the radio wave emitting parts, and the control means 24 may control the outputs of the radiation heater and the radio wave emitting part based on the temperature of the upper surface and the lower surface of the object 11 to be heated. As a result, substantially the entire object to be heated 11 can be heated evenly.

The high-frequency heating apparatus of the present invention includes a detection means 22 for detecting high-frequency waves detected by an antenna 21, and an infrared ray for estimating the temperature of an object 11 to be heated from the infrared rays detected in the heating chamber 10. A sensor 25 and a control means 24 for controlling the output of the radio wave radiating section 20 based on the output of the detection means 22 and the output of the infrared sensor 25 . By estimating the temperature of the lower surface and estimating the temperature of the upper surface of the object to be heated 11 from the output of the infrared sensor 25, and controlling the output of the radio wave emitting unit 20, the heating unevenness of the object to be heated 11 is minimized. Since a heating device can be provided, it can be applied to equipment that heats at high frequencies, such as microwave ovens and high-frequency thawing machines.

REFERENCE SIGNS LIST 10 heating chamber 11 object to be heated 12 inlet 14 second inlet 20 radio wave radiation section 26 second radio wave radiation section 21 antenna 22 detection means 23 waveguide 27 second waveguide 24 control means 25 infrared sensor 40 Input 41, 42 Resistor 43 Diode 44 Capacitor 45 Output

Claims (2)

a heating chamber for storing an object to be heated;
a radio wave radiating section that radiates high frequency waves into the heating chamber from an entrance at the bottom of the heating chamber to heat an object to be heated;
an antenna provided in the lower part of the heating chamber for detecting the high frequency returning from the incident port in the heating chamber;
a detection means for detecting the high frequency detected by the antenna;
an infrared sensor installed in the upper part of the heating chamber and having a plurality of elements for estimating the temperature of the object to be heated from the infrared rays detected in the heating chamber;
a control means for controlling the output of the radio wave emitting unit based on the output of the detection means and the output of the infrared sensor;
The control means estimates the temperature of the lower surface of the object to be heated from the output of the detection means, detects the temperature of substantially the entire upper surface of the object to be heated from the output of the infrared sensor, and detects the temperature of the upper surface of the object to be heated. By estimating the average temperature of almost the entire area, control is performed to weaken the output of the radio wave radiating part over time, and when the average temperature of the upper surface and the temperature of the lower surface of the object to be heated reach approximately the same temperature, the radio wave radiating part A high-frequency heating device characterized by terminating heating. a second inlet at the top of the heating chamber;
a second radio wave radiating section that radiates high frequency waves from the second inlet into the heating chamber to heat an object to be heated;
The control means estimates the temperature of the lower surface of the object to be heated from the output of the detection means, estimates the temperature of the upper surface of the object to be heated from the output of the infrared sensor, and estimates the temperature of the upper surface of the object to be heated. 2. The high-frequency heating device according to claim 1, wherein the output of said radio wave radiating portion is controlled.

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