JP2000215977A - High frequency heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively and ideally heat an object to be heated to its inside by high frequency heating, while preventing overheating of the surface part of the object. SOLUTION: This high frequency heating device has a temperature probe 24 for measuring a temperature of an object 5 to be heated. Plural temperature measurement elements are disposed in the temperature probe 24, while an output from each the temperature measurement element is connected to a control part 11A of a magnetron 2 of a heating means. The temperatures from the core of the heated body 5 to its surface part are measured by inserting a temperature measurement part of the temperature probe 24 into the heated body 5, so that the magnetron 2 of the heating means is controlled according to the measured result to control the temperatures of the inside and the surface part of the heated body 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device for heating foodstuffs with high frequency, wherein the heating is controlled by a temperature probe.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view of a main part of a conventional high-frequency heating device. Magnetron 2 and waveguide 3 outside heating chamber 1
And a high frequency is supplied from the power supply opening 4 into the heating chamber 1. In the heating chamber 1, a heating object 5 is placed on a heating object mounting table 6.
Is placed, and a temperature probe 7 is inserted into the object 5 to be heated. The temperature probe 7 is connected to a receptacle 10 outside the heating chamber 1 via a probe lead wire 9 and an insertion terminal 8, and is connected to a control electronic circuit 11 by a lead wire 12 therefrom.

FIG. 8A is an overall external view of a temperature probe 7 of a conventional high-frequency heating device, and FIG. 8B is an enlarged cross-sectional view of a main part surrounded by a two-dot chain line. The portion surrounded by the two-dot chain line is the tip of the temperature probe 7, and the temperature measuring element 14 is incorporated in this portion. The temperature measuring element 14 is covered with a metal pipe 13, and the temperature measuring element 14 has an element lead 15,
The element lead 16 is connected to the electrodes 17 and 18 of the insertion terminal 8. The wiring including the temperature measuring element 14 is shielded so as not to be affected by the high frequency of the heating chamber 1.

FIG. 9 is a sectional view of a main part of another conventional high-frequency heating device. The high-frequency power supply to the heating chamber 1, the object to be heated, and the mounting table for the object to be heated are the same as those described with reference to FIG. 7, and the finish of the object to be heated is determined according to the surface temperature of the object 5 using the infrared sensor 19. The output value is input to the control electronic circuit 11.

FIG. 10 is a sectional view of a main part of another conventional high-frequency heating device. High-frequency power supply to the heating chamber 1;
The heated object mounting table is the same as that described with reference to FIG. 7, and the finish of the heated object is detected by using the humidity sensor 20 to detect a large amount of evaporated water vapor from the heated object 5 near the finish of the heating, and the signal is sent to the control electronics. This is a configuration for inputting to the circuit 11.

FIG. 11 is a circuit diagram of a conventional high-frequency heating device. A half-wave rectification circuit is formed in the secondary circuit of the high-voltage transformer 23, and high-frequency half-wave rectification is applied to the magnetron 2 to oscillate high frequency. An intermittent relay 22 is connected in series to the primary circuit of the high-voltage transformer 23. I have. Intermittent relay 22
Is controlled by the control electronic circuit 11 in accordance with an input signal from a temperature probe, an infrared sensor, or a humidity sensor, and is turned on / off according to an overheated state of the object to be heated.

[0007]

However, the conventional high-frequency heating apparatus has a drawback in that the object to be heated is heated at a high frequency, that is, the surface of the object to be heated is unnecessarily heated to be dehydrated. In particular, when heating an object to be heated in a large lump with a high frequency, insert a temperature probe into the object to be heated and monitor the temperature at almost the center of the object to be heated, so that the surface temperature does not rise excessively. Output was controlled. In this method, the control content of the high frequency changes according to the weight of the object to be heated and the material of the object to be heated.
An experiment was performed in advance, and a method of programming the approximate control contents into the control electronic circuit was employed. In other words, it is only possible to take measures within a predetermined range, and there is a failure in heating the object to be heated at that point, which is inconvenient.

Even if the method of detecting the heating of the object to be heated uses a humidity sensor, there is no clear relation between the temperature of the surface of the object to be heated and the temperature of the central part. The heating is completed before the temperature of the inside of the object to be heated is not sufficiently increased by the steam generated by the heating.

The same applies to the method of detecting the heating of an object to be heated by an infrared sensor. Since the temperature of the object to be heated is only the surface portion and the internal temperature cannot be detected, the material and weight of the object to be heated are determined in advance. Predicted heating by the program was performed in the category of. In any case, there is a problem that the temperature inside the object to be heated and the surface temperature cannot be simultaneously grasped. There is also a method of using a temperature probe and an infrared sensor or a humidity sensor together, but the use of a control electronic circuit is complicated and expensive, and the infrared sensor and humidity sensor indirectly measure the temperature of the object to be heated. Because of this, the separation of extraneous noise other than the signals from each sensor has always been an issue.

First, in the conventional example shown in FIGS. 7, 8 and 11, the tip of the temperature probe 7 is inserted into the center of the object 5 to be heated, and the measurement result is taken into the control electronic circuit 11.
The high-frequency output of the magnetron 2 is controlled. Since the position of the temperature measuring element 14 of the temperature probe 7 is located at the front end thereof, the heating of the object 5 is controlled by the temperature of the center of the object 5. ing. Heated object 5 by temperature probe 7
Since there is no measurement other than the temperature control at the central portion of the above, the prediction control is performed, and there is a problem that a failure may occur due to overheating of the surface of the object 5 to be heated. Furthermore, even if the insertion position of the temperature probe is other than that shown in the figure, for example, on the surface, the same problem arises because the internal temperature is not known this time.

In the conventional example shown in FIG. 9, the finished state of the object 5 to be heated is detected by the infrared sensor 19 instead of the temperature probe 7 in the conventional examples shown in FIGS. 7, 8 and 11. is there. The infrared sensor 19 detects infrared rays emitted from the object 5 to be heated. However, since the infrared sensor 19 only detects temperature information on the surface of the object 5 to be heated, it cannot detect the inside of the object to be heated. And failure may occur due to insufficient heating inside the object to be heated. Further, the infrared rays are emitted from the inner wall of the heating chamber 1 and the heating object mounting table 6 in addition to the object to be heated.
This also occurs due to an increase in the temperature, causing the surface temperature of the object to be heated to be inaccurately captured, and promoting the above-mentioned failure in heating.

In the conventional example shown in FIG. 10, FIGS.
In the conventional example shown in FIG. 11 and FIG. 11, the finished state of the object to be heated 5 is detected by a humidity sensor 20 instead of the temperature probe 7. The humidity sensor 20 detects water vapor that starts to be emitted in a large amount at that time when the water in the object 5 reaches the boiling point and evaporates. However, since the temperature inside the object to be heated at the time when water vapor is emitted from the surface portion of the object to be heated 5 varies depending on the material of the object to be heated and the weight of the object to be heated, the end of the heating has to be predicted based on a previously experimental value. However, there is still a problem that heating may fail.

Accordingly, a first object of the present invention is to efficiently and more ideally heat the inside of the object to be heated while preventing overheating of the surface of the object to be heated by heating the object by high-frequency heating. And

A second problem is that when a heater, gas or water vapor is added to a high frequency wave to improve the finished state of the object to be heated, those heating means are effectively combined to improve the finish of the object to be heated. To provide a high-frequency heating device.

A third object is to provide a high-frequency heating apparatus in which the accuracy of the temperature measurement in the longitudinal direction of the temperature probe is improved so that the first object can be performed with higher accuracy.

A fourth object is to provide a high-frequency heating apparatus in which the temperature measurement accuracy of each temperature measuring section of the temperature probe is improved so that the first object can be performed with higher accuracy.

A fifth problem is that, while checking the temperature of the object to be heated during heating, the selection of the heating means and the output thereof can be adjusted according to the situation, so that failure of heating of the object to be heated can be prevented, and the desired heating can be achieved. An object of the present invention is to provide a high-frequency heating device that can be used.

[0018]

According to the present invention, in order to solve the above-mentioned problems, a temperature probe for measuring the temperature of an object to be heated has a rod-shaped temperature measuring section, and the rod-shaped temperature measuring section includes a plurality of rod-shaped temperature measuring sections. Are arranged, and outputs from the plurality of temperature measuring elements are connected to a control unit for high-frequency irradiation. For that reason,
By inserting the temperature measuring part into the object to be heated, the temperature from the center to the surface of the object can be measured, and the high-frequency output is adjusted based on the measurement result to control the temperature of the inside and the surface of the object. it can. That is, at the start of heating, heating is started with a strong high-frequency output, and when the surface temperature reaches an appropriate temperature, the high-frequency output is weakened so that the temperature of the surface does not rise excessively. Next, when the temperature of the central portion reaches an appropriate temperature, the heating is completed. Since this heating sequence is performed while actually measuring the temperature of the object to be heated, the object to be heated can be heated as desired. Therefore, it is possible to perform high-speed heating with high frequency without overheating the surface of the object to be heated and insufficient heating inside.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-frequency heating apparatus according to the present invention includes a heating chamber for heating an object to be heated, a magnetron of a high-frequency generation source, a control unit for the magnetron, and a temperature probe for measuring the temperature of the object to be heated. The temperature probe has a rod-shaped temperature measuring section, and the rod-shaped temperature measuring section has a plurality of temperature measuring elements arranged therein, and outputs from the plurality of temperature measuring elements are connected to a control section of the magnetron. By inserting the temperature measuring part of the temperature probe into the object to be heated, the temperature from the center to the surface of the object to be heated is measured, and the heating means is adjusted based on the measurement result. Is controlled.

Further, the heating of the object by high-frequency heating prevents overheating of the surface of the object to be heated while efficiently and more ideally heating the inside of the object to be heated.

Further, an electric heater for heating the object to be heated and a control section for adding gas or water vapor to the high frequency and controlling the heating thereof are provided.

Further, the finish of the object to be heated can be improved.

Further, the plurality of temperature measuring elements of the temperature probe are:
It is configured to be connected and arranged.

Further, the temperature from the surface to the center of the object to be heated can be measured more accurately by the temperature probe, and more accurate heating can be performed.

The temperature measuring section of the temperature probe is an optical fiber, a plurality of tip portions of the temperature measuring points of the optical fiber are arranged in a rod-shaped temperature measuring section, and the output of the infrared ray from the optical fiber is converted into an electric signal. High frequency, heater,
It is configured to be connected to a control unit that controls heating by gas, water vapor, or the like.

Further, the accuracy of temperature measurement of each temperature measuring section of the temperature probe can be improved, and more ideal heating can be performed with high accuracy.

[0027] The apparatus further comprises a control panel of the high-frequency heating device, display means for displaying a measurement result by the temperature probe on the control panel, and adjusting means for adjusting the output of the heating means.

Further, while checking the temperature of the object to be heated during heating, the selection of the heating means and the output thereof can be adjusted according to the situation, so that failure of heating the object to be heated can be prevented, and the desired heating can be performed.

[0029]

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

(Embodiment 1) FIG. 1 is a sectional view of a main part of a high-frequency heating apparatus according to Embodiment 1 of the present invention. 2A is an external view of a temperature probe used in FIG. 1, and FIG. 2B is an enlarged sectional view of a main part thereof. FIG. 5 is a circuit diagram of FIG. 1, FIG. 6 (a) is an explanatory diagram of a temperature measurement value of an object to be heated at the time of high-frequency heating by the temperature probe of FIG. 1, and FIG. FIG.

In FIG. 1, the high frequency generated by the magnetron 2 is guided into the heating chamber 1 through the waveguide 3 and the power supply opening 4, and the object 5 placed on the object mounting table 6 is heated. You. The tip of the temperature probe 24 is inserted into the object 5 so as to stop near the surface of the object 5 and pass through the center of the object 5. As shown in FIG. 2A, the temperature probe 24 is inserted into the metal pipe 13 inserted into the object 5 to be heated as shown in FIG.
4 are arranged in large numbers. As the temperature measuring element 14, an element whose electric characteristics change with temperature, such as a negative resistance, is used. Each temperature measuring element 14 is connected by an element common lead wire 29 of common wiring and each element lead wire 30 to each temperature measuring element 14, and the element common electrode 27 and the element electrode 28 It is wired to. From these temperature measuring element 14 to the insertion terminal 26, a probe lead 25
And is shielded from high frequencies. The insertion terminal 26 of the temperature probe 24 is connected to a receptacle 31 outside the heating chamber 1, from which the control electronic circuit 1 is connected via a lead wire 32.
It is connected to 1A. As a result, the measured value of the temperature probe corresponding to the temperature of the surface portion and the temperature of the central portion of the object to be heated 5 is taken into the control electronic circuit 11A, and the high-frequency output control can be performed accordingly.

Next, high-frequency output control will be described with reference to the circuit diagram of FIG. The high frequency transformer 23 is used for the magnetron 2 to generate a high frequency. High-frequency output control is performed by high-voltage transformer 23.
The connection of the contact of the intermittent relay 22 is intermittently connected to the primary circuit, and the operation is performed according to the intermittent frequency. The intermittent signal is the control electronic circuit 11
A is generated at A and drives the coil of the intermittent relay 22. The control signal of the control electronic circuit 11A is determined based on the temperature measurement result of the object 5 to be heated by the temperature probe 24.

The contents of the control will be described with reference to FIG. The horizontal axis of the graph indicates the position including the tip of the temperature probe 24, the vertical axis indicates the measured temperature value of the temperature measuring element 14 of the temperature probe 24, and the curve in the graph indicates the temperature measuring element 14
Are connected by a line. The result shown in the graph is a state after the object 5 has been heated to a high frequency to some extent, but the surface of the object 5 has a higher temperature than the central part.
Since the temperature probe 24 is inserted so that the tip end stops at the surface of the object 5 to be heated, a value of the thermosensitive element 14 corresponding to the temperature of the object 5 is output from the temperature probe 14. Since the temperature of the portion of the temperature probe 24 protruding from the object to be heated 5 is lower than that of the inside of the object to be heated 5, the curve becomes as shown in FIG. The temperature of the object to be heated 5 is controlled by the temperature probe 2
The temperature at the tip of 4 is defined as the temperature of the surface of the article 5 to be heated, and the valley of the temperature following the tip is defined as the temperature of the center of the article 5 to be heated. The temperature of the surface and the center of the article 5 to be heated is controlled by changing the high-frequency output based on the temperature of the surface and the center as control data. In other words, when the high frequency is increased, the temperature of the surface increases faster than that of the center. Further, when the high frequency is weakened, the temperature difference between the surface portion and the central portion becomes small due to the heat conduction inside the object to be heated. By utilizing this feature, the heating temperature of the object to be heated is controlled. This tendency of the temperature of the object to be heated 5 is applicable to almost any object to be heated, and the temperature of the surface portion and the central portion of the object to be heated is always grasped by simply inserting the temperature probe 24 into the object to be heated. In addition, it is possible to efficiently and freely heat the object to be heated by eliminating overheating of the surface of the object to be heated and insufficient heating inside the object. The heating control corresponding to the actually measured temperature of the object to be heated is performed by a control electronic circuit 1.
Automatic heating is possible by incorporating a heating sequence into 1A in advance, and of course, manual operation is also possible.

It should be noted that the temperature accuracy of the temperature measuring point inside the object to be heated by the temperature probe is improved if the temperature measuring elements 14 are connected and arranged, so that the measurement can be performed more finely. The description of this point can be understood without depending on the drawings, and the drawings are omitted. Further, the metal pipe 13 surrounding the temperature measuring element 14 is thinner and has a lower thermal conductivity, so that the heat at the measuring point is less likely to diffuse through the metal pipe, so that the temperature measurement accuracy is further improved.

(Embodiment 2) FIG. 3 is a sectional view of a main part of a high-frequency heating apparatus according to Embodiment 2 of the present invention.

The circuit diagram of FIG. 5 and the explanatory diagram of the measured value of the temperature of the object to be heated by the temperature probe of FIG. 6 are used in the description of FIG. 1, but the functions of the embodiment 2 of FIG. And explanations, which are also used in this explanation. The description of the overlapping portions of FIG. 3 and FIG.

The difference from the first embodiment is that a heating source for the article 5 to be heated is added to a high frequency and a heater or steam is added. In the description using gas, only the heat source using an electric heater is replaced with a gas burner, and the function of heating is the same as that of the heater.

Referring to FIG. 3, first, the heat source to the object 5 to be heated by the heater will be described. A convection fan 34 is provided on the outside facing the wall surface of the heating chamber 1, and a convection heater 33 is arranged therearound. On the wall surface of the heating chamber 1 facing the convection fan 34, there is an opening hole 37 through which the air in the heating chamber 1 enters and exits.
When 3 is energized and the convection fan 34 rotates, hot air flows into the heating chamber through the opening 37. Next, as for the heat source by steam, water 35 above the steam generator 51 disposed outside the heating chamber 1 is dropped on the evaporation heater 36 through the water supply valve 38 to generate steam, and the steam is generated on the wall surface of the heating chamber 1. Is fed into the heating chamber 1 through the opening hole 52 of the heater. The control of the heater and the steam will be described with reference to FIG. The convection heater 33 controls the amount of electricity by turning the heater relay 39 on and off to control the temperature of the heating chamber 1. The water vapor is supplied to the evaporator 3
6 is controlled, and the amount of generated steam is controlled by controlling the water supply valve 38. Similarly to the high-frequency control described in the first embodiment, the control of the heater and the steam is performed by the control electronic circuit 11A. Of course, the selection of the high frequency wave, the heater, and the steam and the respective outputs are determined by the temperature probe 24 based on the temperatures of the surface portion and the central portion of the object 5 to be heated.

Next, the control of the temperature of the object 5 to be heated by the temperature probe 24 will be described with reference to FIG. 6B <at the time of heating by high frequency and heater, gas, water vapor, etc.>. FIG.
FIG. 3 is similar to FIG. 1, but the temperature of the heating chamber 1 is higher than when only high frequency is used. Therefore, the portion of the temperature probe 24 outside the object 5 to be heated is higher than the temperature of the object to be heated, and the temperature measurement curve is different from that of the first embodiment. Also in this case, the tip of the temperature probe 24 indicates the temperature of the surface of the object 5 to be heated, and the valley of the temperature following the tip is the temperature of the center of the object 5 in the first embodiment. Since the temperature of the surface portion and the inside of the object to be heated 5 can be grasped, the heating control of the object to be heated 5 using the control electronic circuit 11A can be performed even if heating by a heater or steam is applied. Can be controlled similarly to Particularly, in the simultaneous heating of the high frequency and the electric heater or the steam, the temperature of the surface of the article 5 to be heated tends to be higher than that of the single heating of the high frequency. Even in such a case, the temperature probe 2
4 directly monitors the temperature of the object 5 to be heated, so that heating utilizing the characteristics of each of the hot air and steam flowing into the heating chamber 1 can be performed in addition to the high-frequency heating, and the heating of the object to be heated is effectively finished. I can do it.

(Embodiment 3) FIG. 4A is an external view of a temperature probe using an optical fiber according to Embodiment 3 of the present invention.
(B) is an enlarged cross-sectional view of a main part. This embodiment is similar to the first embodiment.
Alternatively, the temperature probe 24 of the second embodiment is replaced by a temperature probe using an optical fiber, and functions other than the temperature probe are the same, and description thereof will be omitted.

As shown in FIG.
Are bundled, and the leading ends of the bundles are sequentially shifted as the temperature measuring unit 43. The entire optical fiber is covered with a fixed resin 44 having a small dielectric constant with respect to a transparent high frequency, and is integrated. Infrared rays incident from the measuring section correspond to the temperature of that section. The infrared light of the optical fiber is input to the control electronic circuit 11A through the conversion circuit 45 for converting light into an electric signal shown in FIG.
Performs the same operation as. In the present embodiment, since the temperature measurement unit 43 directly receives the infrared light emitted from the object 5 to be heated, the measurement error due to the indirect measurement of the temperature of the object to be heated using the conventional humidity sensor or infrared sensor (“the object to be heated” Even if the central part is underheated, the humidity sensor works by heating only the surface part "," The infrared sensor cannot determine the temperature of the heated object itself due to the presence of a heated part or reflective material other than the heated object ")
There is no, temperature measurement comes out accurately and with good response,
Since the temperature of the object to be heated can be grasped more accurately, more ideal heating can be performed with high accuracy.

(Embodiment 4) FIG. 5 shows a control panel according to Embodiment 4 of the present invention.

The control panel 46 has a display panel 47 indicating the internal temperature of the object to be heated, a high-frequency output adjustment knob 48, a heater output adjustment knob 49, and a steam output adjustment knob 50. The display panel 47 displays the curve shown in FIG. The person who heats the output adjustment knob 48, while watching the display panel, adjusts the heating level of the object 5 to be heated.
Alternatively, the adjustment can be performed with the output adjustment knob 49 or the output adjustment knob 50. Since the temperature of the object to be heated 5 is constantly measured during heating, the result is also displayed on the display panel. Of course,
The display can also be displayed digitally. Temperature control of the temperature of the object to be heated, selection of the heating means are also predetermined conditions,
Automatic operation is possible if programmed according to the procedure.However, it is possible to confirm the operation state because the actual temperature of the object to be heated is always measured, and reliable heating can be performed without relying on experience or intuition. I can do it.

[0044]

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

Heating can be advanced while grasping the internal temperature including the surface portion of the object to be heated by using a temperature probe for multipoint measurement. The heating sequence appropriate for the material can be easily performed, and the taste can be pursued.

[Brief description of the drawings]

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

FIG. 2A is an external view of a temperature probe according to Embodiments 1 and 2 of the present invention. FIG.

FIG. 3 is a sectional view of a main part of a high-frequency heating device according to a second embodiment of the present invention.

4A is an external view of a temperature probe using an optical fiber according to a third embodiment of the present invention, and FIG.

FIG. 5 is a circuit diagram including a first embodiment, a second embodiment, a third embodiment, and a fourth embodiment of the present invention, and a diagram of a control panel.

FIG. 6 (a) Embodiments 1, 2, and 3 of the present invention.
Explanatory drawing of the measured value of the object to be heated at the time of high-frequency heating by the temperature probe shown in FIG.

FIG. 7 is a cross-sectional view of a main part of a conventional high-frequency heating device.

8A is an external view of a conventional temperature probe, and FIG.

FIG. 9 is a sectional view of a main part of another conventional high-frequency heating device.

FIG. 10 is a sectional view of a main part of another conventional high-frequency heating device.

FIG. 11 is a conventional circuit diagram.

[Explanation of symbols]

 Reference Signs List 1 heating chamber 2 magnetron 5 object to be heated 11A control electronic circuit 14 temperature measuring element 24 temperature probe 41 optical fiber temperature probe 42 optical fiber 43 temperature measuring section 46 control panel 47 display panel

Claims (5)

[Claims] 1. A heating chamber for heating an object to be heated, a magnetron of a high-frequency source serving as a heating means, a control unit of the magnetron, and a temperature probe for measuring the temperature of the object to be heated. , A rod-shaped temperature measuring unit, wherein the rod-shaped temperature measuring unit is provided with a plurality of temperature measuring elements, and outputs from the plurality of temperature measuring elements are connected to a control unit of the magnetron to measure the temperature of the temperature probe. The temperature from the center to the surface of the object to be heated is measured by inserting a warm part into the object to be heated, and the heating means is adjusted based on the measurement result. High frequency heating device that controls temperature. 2. The high-frequency heating apparatus according to claim 1, further comprising an electric heater for heating the object to be heated, a control unit for adding gas or water vapor to the high frequency, and controlling the heating of the high frequency. 3. The high-frequency heating apparatus according to claim 1, wherein the plurality of temperature measuring elements of the temperature probe are connected and arranged. 4. A temperature measuring section of the temperature probe is an optical fiber, a plurality of tip portions of temperature measuring points of the optical fiber are arranged in a rod-shaped temperature measuring section, and an infrared output from the optical fiber is converted into an electric signal. High frequency, electric heater,
The high-frequency heating device according to claim 1 or 2, wherein the high-frequency heating device is connected to a control unit that controls heating by gas, water vapor, or the like. 5. A high-frequency heating apparatus comprising: a control panel of a high-frequency heating device; display means for displaying a measurement result by a temperature probe on the control panel; and adjusting means for adjusting the output of the heating means. The high-frequency heating device as described.