JPH0864356A - High frequency heating device - Google Patents

Abstract

PURPOSE: To conduct combined heating only with microwave energy by switching a shutter in a wave guide for heating purpose, and conducting microwave heating and infrared heating with a microwave heating element. CONSTITUTION: A cooking material 9 is placed on a saucer 11, and warmed, oven-cooked, or heated by selecting a menu key. When the material 9 is warmed, a shutter 7 is set to a position B by selecting the key, a magnetron 6 is oscillated and microwave is introduced into a heating chamber 3 by controlling the shutter 7, to warm the material 9. When the material 9 is oven-cooked, the shutter 7 is set to a position A, the microwave is introduced into a heating chamber 4 to heat a microwave heating element 10, and to heat a microwave thermal insulation plate 2 to heat the material 9 with radiation heat and convection heat of the plate 2. When the material 9 such as meat is warmed, the first procedure is the same as when the material 9 is warmed mentioned above, but hot air generating from the material 9 is detected with a temperature detecting element 17, and the shutter 7 is switched to the position A when heating reaches at optimum temperature, then heating is continued same as the oven-cooking.

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 by microwave.

[0002]

2. Description of the Related Art A high-frequency heating apparatus typified by a microwave oven is provided with a heater for heating cooked food and a magnetron for microwave heating, and a heater and a control device for controlling energization to the magnetron to heat the heater. When performing the heating, the control device controls the energization of the heater to heat the cooking product, and when performing the microwave heating, the control device controls the energization of the magnetron to heat the cooking product.

As a method of heating the heater, a sheath heater was generally installed in the heating chamber at the beginning, but since the heater is exposed in the heating chamber, it disturbs the cleaning and is uneasy in appearance. Therefore, a heater is provided outside the heating chamber, and hot air generated by the heat source of the heater is circulated in the heating chamber to heat the food. This method has the feature that you can cook a large amount of food at once by setting the food to be cooked in two stages, but on the other hand, the structure is complicated, the external dimensions of the product are large, and the price is high and the installation is expensive. There was a space limitation.

Therefore, the following two systems are roughly classified into the popular type microwave ovens. That is, a planar heater insulated with a laminated mica plate is adhered to the back surface of the wall of the heating chamber, and the heat of the generated heater heats the wall of the heating chamber to indirectly heat the food in the heating chamber and the inside of the ceramic pipe. In this method, a pipe heater accommodating a heating wire such as a nichrome wire is attached to the recess formed in the heating chamber to directly heat the food, and this or a combination thereof is used.

In the microwave heating method, an opening for introducing radio wave energy from the magnetron is provided in the heating chamber, and the radio wave energy is radiated from the opening into the heating chamber through a waveguide to induce cooking. In order to prevent the inside of the door finder from becoming fogged due to water vapor from the cooking product generated during heating, the heating chamber has an inlet port for sending air from the fan for cooling the electric parts into the heating chamber. Is provided on the wall surface of the heating chamber near the door, and an exhaust port for discharging steam or hot air from the cooked food to the outside of the body is provided on the wall surface of the heating chamber on the side opposite to the air inlet.

[0006]

In the above-mentioned conventional technique, in which the heater is attached to the outside of the heating chamber as in the system, the water vapor generated during the heating of the food is small holes or portions on the wall surface of the heating chamber. May infiltrate through the gaps and adhere to the surface of the heater or the end portion of the heater, which may lower the insulation of the heater depending on the insulation treatment method and may cause electric shock.There are also design restrictions such as unit price of parts and miniaturization of parts. Therefore, the watt density of the heater must be designed to be high, and the heater is used at a high temperature. Therefore, depending on the insulation treatment method, the insulation of the heater may be lowered and there is a risk of electric shock.

Further, in the case where a heater is installed in the heating chamber as in the method, water vapor generated during the heating of the cooked material adheres to the surface of the heater and the terminal portion, and the insulation of the heater is lowered depending on the insulation treatment method. There was a risk of electric shock.

Further, the heating chamber is provided with an inlet and an outlet, and during heating, hot air generated from the cooked food gathers at the exhaust port, so that the surface of the cooked product near the exhaust port Was easily burnt, and the surface of the cooked food near the air inlet tended to become thin due to the influence of the outside air, making uniform heating difficult.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a heating chamber, a magnetron, a waveguide, a saucer on which food is placed, and a control device equipped with a microcomputer. In the high-frequency heating device consisting of
The heating chamber is composed of an object heating chamber A (hereinafter referred to as heating chamber A) and a microwave heating element heating chamber B (hereinafter referred to as heating chamber B) via a radio wave shielding plate. B is provided with an opening A and an opening B for introducing microwave energy from the magnetron, and a branch portion is provided in the middle of the waveguide coupled to the magnetron to form the opening A.
A shutter for restricting the progress of microwaves by a control device is provided at a branch portion, a microwave heating element is provided on the side of the heating chamber B on the radio wave shielding plate, and the heating chamber is switched by switching the shutter. A structure in which the food in A is heated by microwave heating from the opening A and by heat radiation and convection heat that is heated by a microwave heating element that is heated by the microwave from the opening B did.

Further, if the heating value of the microwave heating element is higher on the inlet side of the heating chamber A and lower on the outlet side, more uniform heating is possible.

It is also possible to construct a plurality of microwave heating elements with different heating values.

It is also possible to automatically switch the shutter during heating to perform combined heating by combining different heating methods.

Furthermore, the operation of the magnetron can be stopped during the shutter switching operation to prevent sparks at the connection between the shutter and the waveguide.

[0014]

The heating chamber having the above structure is divided into a heating chamber A for heating an object to be heated (heating chamber A) and a heating chamber B for microwave heating element B (heating chamber B) by a radio wave shielding plate. Are provided with an opening A and an opening B for introducing microwave energy from the magnetron, respectively, and a branch portion is provided in the middle of the waveguide coupled to the magnetron to connect to the opening A and the opening B to control the control device. A shutter for restricting the progress of microwaves is provided by means of the microwave heating through the opening A of the heating chamber A and the microwave heating element that generates heat from the microwaves through the opening B. By heating with the heater, there is no fear of electric shock due to defective insulation treatment of the heater.

Further, the heating value of the microwave heating element provided on the radio wave shielding plate is high on the inlet side of the heating chamber A and low on the outlet side, so that it may be affected by the outside air from the inlet. Instead, the food in the heating chamber A is uniformly heated.

Further, the microwave heating and the infrared heating by the heat generation of the microwave heating element can be performed by automatically switching the shutter in the waveguide.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional view and system configuration diagram of a heating chamber of a high-frequency heating apparatus showing an embodiment of the present invention, and FIG.

In the figure, reference numeral 1 denotes a heating chamber, which is composed of a heating chamber A3 and a heating chamber B4 which are partitioned by a radio wave shielding plate 2 in which an end portion 2a of a metal plate such as stainless steel is welded to a side wall of the heating chamber 1. The aperture A3a and the aperture B for introducing the radio wave energy oscillated from the magnetron 6
4a is provided. The opening A3a and the opening B4
In a, hot air and water vapor do not flow out from the heating chamber B4 to the magnetron 6, microwaves are easily transmitted, and are blocked by a partition plate A3b and a partition plate B4b made of a mica plate or the like having high heat resistance. Reference numeral 5 is a waveguide having a branch portion 5a connecting the magnetron 6 with the opening A3a and the opening B4a. The branch portion 5a is axially supported by both walls 5b and 5c of the waveguide 5, and the opening A3a or the opening A shutter 7 capable of closing B4b is provided. The shutter 7 is made of aluminum as shown in FIG. 3, and its surface is subjected to alumite treatment 7a so as to prevent sparks from being generated at the position <a> or <b> during the heating operation. Alternatively, the surface of the metal plate may be coated with an insulating film such as fluorine resin to prevent sparks. Reference numeral 7b denotes a shutter shaft, which penetrates both walls of the waveguide 5 through bearings 7c made of a fluorine-based composite resin attached to both ends thereof. Pipes 5b1 and 5c1 are formed in the peripheral portion of the through hole in such a size that the microwave is cut off, and the electric waves in the waveguide 5 are prevented from leaking out from this portion. In order to prevent the door finder (not shown) from being fogged by steam generated from the cooking product 9 during heating, the heating chamber A3 is provided with an inlet port 3c on the side wall of the heating chamber A3 near the door finder, An air inlet duct 8 is joined to the outer wall surface of the air inlet 3c, and a side wall opposite to the air inlet 3c is provided for discharging oil fumes, odors, etc. generated from the cooked food 9 to the outside of the body during heating. An exhaust port 3d is provided. A microwave heating element 10 is attached to the upper surface of the radio wave shielding plate 2 on the heating chamber B4 side with an adhesive 10a. Reference numeral 11 is a saucer on which the food 9 is placed.

Reference numeral 12 is an operation panel, and 13 is a menu key housed in the operation panel. Reference numeral 14 is a control device equipped with a microcomputer, which checks whether or not the shutter 7 is at a prescribed position according to a menu and, if it is not at the prescribed position, operates the motor 15 to move the shutter 7 linked to the motor shaft 15a to the prescribed position. Rotate to <a> or <b>. Reference numeral 16 is a microswitch, which corresponds to a cam (not shown) provided on the motor shaft 15a. Reference numeral 17 denotes a temperature detecting element arranged in the vicinity of the exhaust port 3d, which detects hot air generated from the cooked food 9 and inputs the temperature information to the control device 14.

Here, the microwave heating element 10 is Mg
Ceramics in which a proper amount of a component containing O, SiO2, Al2O3, LiO, etc. (in this embodiment, a trace amount of carbon or iron oxide is contained in order to increase the heat generation amount) is mixed and fired at a desired heat generation temperature. It is composed of.
The adhesive 10a is made of forsterite-based ceramic having a coefficient of thermal expansion close to that of metal.

Further, the microwave heating elements 10 on the surface of the radio wave shielding plate 2 are densely arranged on the side of the air inlet 3c so that the calorific value is high, and are roughly arranged on the side of the exhaust port 3d so that the calorific value is low. It is configured. In order to make this heat generation amount different, a combination of microwave heating elements 10 having different heat generation saturation temperatures is combined, the microwave heating element 10 having a high saturation temperature is arranged on the side of the inlet 3c, and the side of the exhaust port 3d is set to the temperature of the saturation temperature. It is also possible to dispose a low microwave heating element 10.

Next, the operation of this embodiment will be described.

When heating cooked food 9 such as chilled rice,
After placing and storing the cooked food 9 on the saucer 11 in the heating chamber A3, select the corresponding menu key 13 on the operation panel 12 surface,
When the start button (not shown) is pressed, it is checked whether the shutter 7 is in the specified position according to the command from the control device 14, and if it is not the specified position, the motor 15 is activated to operate the motor shaft 15a. The shutter 7 linked to is rotated to the specified position <b>. The magnetron 6 starts to oscillate after the shutter 7 reaches the predetermined position, and the microwaves branch off the waveguide 5 from the waveguide 5.
In step a, the shutter 7 is regulated to move toward the heating chamber A3 and is guided through the opening A3a into the heating chamber A3 to heat the cooking product 9 by microwave.

Next, the case of oven cooking will be described.

After the food 9 to be cooked in the normal oven such as cookies is placed and stored in the tray 11 and the menu selection operation is performed in the same manner as described above, the shutter 7 is set to the specified position <a>, and then the magnetron is set. The microwave from 6 travels in the direction of the opening B4a, and from the opening B4a the heating chamber B
4 is heated in the microwave heating element 10. The microwave heating element 10 is made by mixing components of ceramic materials having different dielectric losses in advance so as to reach a preset temperature and firing and solidifying the components, and the degree of absorption of microwaves varies depending on the magnitude of the dielectric loss (increasing the dielectric loss. The higher the heat generation temperature, the easier it is for microwaves to absorb). In this embodiment, the heat generation saturation temperature due to microwave absorption is about 1000 ° C. Incidentally, the exothermic saturation temperature can be set from about 600 ° C. to about 1200 ° C. by blending the components. Ordinary substances have problems such as destruction and decomposition at this temperature, but since they are made of ceramic, there is no such problem. The radio wave shielding plate 2 is heated by the heat of the microwave heating element 10 that has generated high temperature, and the cooking product 9 in the heating chamber A3 is heated by the heat radiation and convection heat from the radio wave shielding plate 2. At this time, the opening B4a is closed by the partition plate B4b to prevent heat generated from the microwave heating element 10 from flowing out of the heating chamber B4 into the waveguide 5, thereby shortening the life of the magnetron 6 due to thermal deterioration. To prevent. Further, since the microwave heating element 10 is arranged on the radio wave shielding plate 2 so that the heat generation amount is high on the inlet 3c side and the heat generation amount is low on the exhaust port 3d side, the cooked food 9 in the heating chamber A3 is Is heated by the high heat radiation on the inlet 3c side and the low heat radiation on the exhaust 3d side.

Next, the case of heating the cooked meat 9 will be described.

After the food 9 is placed on the tray 11 and stored, the menu selection operation is performed in the same manner as described above. The control device 14 receives the information of the menu instructed from the operation panel 12,
The optimum heating method corresponding to this is instructed to each system.

First, the shutter 7 is set to a specified position <b> for microwave heating, and then the magnetron 6 is set.
Starts to oscillate, and the microwave advances toward the heating chamber A3 due to the restriction of the shutter 7 at the branching portion 5a of the waveguide 5, and is guided into the heating chamber A3 through the opening A3a to microwave-heat the food 9 to be cooked. . At this time, the temperature detecting element 17 arranged near the exhaust port 3d detects the hot air generated from the cooked food 9 and inputs the temperature information to the control device 14. When the cooked food 9 is heated to an appropriate temperature, the shutter motor 15 is operated by the command of the control device 14 to shift to the next heating operation, and the shutter 7 is rotated <a>.
Is set to the position. By suspending the operation of the magnetron 6 during this operation, sparks at the contact portion between the shutter 7 and the waveguide 5 are prevented. Subsequently, the microwave advances toward the opening B4a due to the restriction of the shutter 7 of the branch portion 5a of the waveguide 5, and is guided into the heating chamber B4 from the opening B4a to heat the microwave heating element 10. The radio wave shield 2 is heated by the heat of the microwave heating element 10 that has generated high temperature, and the cooking time 9 in the heating chamber A3 is set by the heat radiation and convective heat from the radio wave shield 2 (here Then, the temperature detecting element 17 and the microcomputer of the control device 14 heat for a time period calculated by multiplying the time period of the first microwave heating by a constant determined by an experiment).

In this way, the microwaved food 9 is first prepared.
After heating to a suitable temperature, the shutter 7 is automatically switched and the infrared rays from the microwave heating element 10 are continuously heated, so that meat and the like can be heated inside and the surface can be burnt. You can finish it deliciously.

As shown in FIG. 4, a plurality of small holes 2b may be partially formed in the radio wave shielding plate 2 so that the heat energy of the microwave heating element 10 which has generated heat can be directly radiated into the heating chamber A3. . At this time, there is also a method of applying a coating 18 treatment with a ceramic base material on the surface of the radio wave shielding plate 2 on the heating chamber A3 side in order to prevent clogging caused by scattered scattered debris such as the food 9 being attached to the small holes 2b. The coating 18 also has the effect of favoring thermal radiation by using a black substrate. Moreover, if the adhesion with the microwave heating element 10 can be strengthened through the small hole 2b, the effect cannot be ignored.

[0032]

As described above, according to the present invention, the heating chamber is divided into the heating chamber A for the object to be heated (heating chamber A) and the heating chamber B for the microwave heating element (heating chamber B) by the radio wave shielding plate. Room A
And the heating chamber B is provided with an opening A and an opening B for introducing microwave energy from the magnetron, and a branch portion is provided in the middle of the waveguide coupled to the magnetron to connect to the opening A and the opening B, A shutter for restricting the progress of microwaves is provided under the control of the control device, and microwave heating from the opening A of the heating chamber A and heat generated by the microwave heating element that generates heat from the microwaves from the opening B are transmitted through the radio wave shielding plate. By heating with radiant / convective heat, there is no danger of electric shock due to poor insulation treatment of the heater, and there is a high level of safety. By making the mouth side high and the exhaust side low, the cooked food in the heating chamber A can be heated uniformly without being affected by the outside air from the inlet. It enables an infrared heating by heat generation of the microwave heating and the microwave heating device by the automatic switching of the shutter in the tube there is provided a high-frequency heating device capable of complex heated only by the microwave energy.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view and system configuration diagram of a heating chamber of a high-frequency heating device showing an embodiment of the present invention.

FIG. 2 is likewise a sectional view of an essential part.

FIG. 3 is likewise a sectional view of a shutter.

FIG. 4 is another example of the radio wave shielding plate.

[Explanation of symbols]

 1 heating chamber 2 radio wave shielding plate 2b small hole 3 heating chamber A 3a opening A 3b partition plate A 3c air inlet 3d exhaust port 4 heating chamber B 4a opening B 4b partition plate B 5 waveguide 5a branching part 6 magnetron 7 shutter 9 Cooked food 10 Microwave heating element 12 Operation panel 14 Control device 17 Temperature detection element

Claims (5)

[Claims] 1. A heating chamber (1) and a magnetron (6)
In a high-frequency heating device comprising a waveguide (5), a saucer (11) on which a food item (9) is placed, and a control device (14) equipped with a microcomputer, the heating chamber (1) is exposed to radio waves. A heating chamber A for an object to be heated (hereinafter referred to as heating chamber A) (3) and a heating chamber B for a microwave heating element through a shield plate (2).
(Hereinafter referred to as heating chamber B) (4), and an opening A (3a) for introducing microwave energy from the magnetron (6) into the heating chamber A (3) and the heating chamber B (4), respectively. ) And an opening B (4a) are provided, and a branch portion (5) is provided in the middle of the waveguide (5) coupled to the magnetron (6).
a) is provided and branched to form an opening A (3a) and an opening B (4
a), and the branch unit (5a) is connected to the control device (1
The shutter (7) for restricting the progress of microwaves is provided by 4), and the microwave heating element (10) is arranged on the side of the heating chamber B (4) on the radio wave shielding plate (2). By switching between the two, the cooking material (9) in the heating chamber A (3) is heated by the microwave heating from the opening A (3a) and the microwave heating element (10) that generates heat by the microwave from the opening B (4a). Radio wave shield (2)
A high-frequency heating device characterized in that heating is performed by heat radiation and convection heat via the. 2. The heating value of the microwave heating element (10) is set such that the heating chamber A (3) has a high air intake port (3c) side and a low air exhaust port (3d) side. Item 1. The high frequency heating device according to item 1. 3. The high-frequency heating device according to claim 1, wherein the microwave heating element (10) comprises a plurality of microwave heating elements having different heating values. 4. The high-frequency heating apparatus according to claim 1, 2 or 3, wherein the shutter (7) is automatically switched during heating so as to perform combined heating by combining different heating methods. 5. The high frequency heating apparatus according to claim 1, wherein the operation of the magnetron (6) is stopped during the switching operation of the shutter (7).