JP2000130764A - High frequency heating device with heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the temperature of a wall surface to which a heat sensitizing part is attached with good response and accurately control temperature in the constitution of the heat sensitizing part for controlling the temperature of a heating chamber. SOLUTION: The periphery of a metal pipe 23 is covered with a metallic cover 26 and the metal pipe 23 is attached to a heating side wall 21 through an attaching plate 27 so that they come into direct contact with each other. Electric field is not applied to the metal pipe 23 so that a self-heat generation due to high frequency current is eliminated. When both high frequency heating and electric heating are emplyed, the deterioration of a finishing state can be more eliminated than that upon heating only by the electric heating. Further, an opening 28 is provided between the metal pipe 23 and the heating side wall 21, so that the influence of heat from an electric heater transmitted directly to a heat sensitive element 24 through the heating side wall 21 is reduced and the temperature of a heating chamber can be more accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a temperature control device in one or both of electric heating and high-frequency heating chambers.

[0002]

2. Description of the Related Art Conventionally, the structure of a heat-sensitive portion 22 for controlling the temperature of a heating chamber 3 of a heating device for selectively heating either or both of electric heating by an electric heater and radio wave heating by a microwave oven is described. For example, 7-975
The thing described in No. 19 gazette was common. As described in the present invention, various inventions have been made to improve durability and corrosion resistance. FIG. 5 shows an example of such a method in which the thermal element is completely covered with metal.

As shown in FIG. 6, a heat sensing element 24 is provided near a sealed portion inside a thin metal cylinder 23 having one end sealed to prevent the ingress of high frequency, as shown in FIG. A portion is provided so as to protrude into the heating chamber 3, and the heat-sensitive portion 22 is attached by fixing a part of a mounting plate 27 that is in pressure contact with the metal cylinder 23 to the heating chamber side wall 21 constituting the heating chamber 3. The metal tube 23 has a sharp tip, so that the user does not suffer any damage due to accidental strong contact during use or during cleaning after use, and to prevent damage to the heat-sensitive portion 22. It is arranged in an extremely deep part in the heating chamber 3. Further, as the gap between the metal cylinder 23 and the heating chamber side wall 21 increases, high-frequency leakage occurs from the gap between the metal cylinder 23 and the heating chamber side wall 21 during high-frequency heating.

[0004]

However, the heat-sensitive element 24 is disposed near the sealed portion inside the metal tube 23, and this portion is provided so as to protrude into the heating chamber 3, and the mounting plate 27 is pressed against the metal tube 23. In the case of the heat sensing part 22 having a configuration in which a part of the heating part is fixed to the heating chamber side wall 21 constituting the heating chamber 3, when the high frequency heating and the electric heating are used together, the finished state is deteriorated as compared with the case where the heating is performed only by the electric heating. Occurred. In addition, the electric heating also has a problem in that there is a difference in the type and form of the food to be heated and that the change during repeated heating is large. Since the position of the heat-sensitive portion 22 is far from the object to be heated, and conversely close to the electric heating device, the temperature applied to the food cannot be accurately detected, and the metal tube 23 becomes an antenna during high-frequency electric heating, and from self-heating by high-frequency current, The temperature of the heat-sensitive element 24 exceeds the temperature rise due to the electric heating.
As a result, before the temperature of the heating chamber 3 reaches the set temperature, the electric heating device is shut off to be in an unheated state. In order to more accurately grasp the temperature of the object to be heated, the length of the metal tube 23 of the heat sensitive portion 22 is increased and the heating chamber 3 is heated.
It is known that inward extension is a powerful method, but in this case, the adverse effect that the antenna effect at the time of high-frequency heating becomes more remarkable is produced.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to cover the periphery of the heat-sensitive portion with a metal cover, further cover a metal tube covering the heat-sensitive portion, and a heating wall constituting a heating chamber. Is mounted so as not to directly contact the metal tube.

According to the above invention, the application of the electric field to the inner portion of the metal cylinder is eliminated by covering with the metal cover, and the self-heating due to the high-frequency current is eliminated. When the high-frequency heating and the electric heating are used in combination, the deterioration of the finished state can be eliminated as compared with the case where the heating is performed only by the electric heating. Furthermore, by adopting a configuration in which a high-frequency electric field is not applied to the heat-sensitive portion, a gap is provided between the metal tube of the heat-sensitive portion and the heating wall that forms the heating chamber, and a configuration can be installed without direct contact. Therefore, the effect of heat from the electric heater which is directly heated through the heating wall to the heat sensitive part is reduced, and the temperature in the heating chamber can be detected more accurately.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a heating chamber in a main body, and one of high-frequency heating and electric heating,
Alternatively, an apparatus for selectively enabling both at the same time is provided, and further, a temperature-sensitive part provided with a heat-sensitive element in the vicinity of a sealed part of a metal cylinder whose one end is closed for controlling the temperature of the heating chamber is provided in the heating chamber. In addition to protruding, the periphery of the heat-sensitive portion has air permeability, and is covered with a metal cover that does not allow high-frequency heating to enter, and the outer periphery of the metal cylinder of the heat-sensitive portion and the heating wall forming the heating chamber are The mounting configuration does not directly contact.

[0008] By covering with a metal cover, the application of an electric field to the metal cylinder portion is eliminated, and the self-heating due to the high-frequency current is eliminated, so that the temperature of the heat-sensitive portion becomes the same regardless of the application of the high-frequency current. When electric heating is used in combination, deterioration of the finished state can be eliminated as compared with the case where heating is performed only by electric heating. Further, by adopting a configuration in which a high-frequency electric field is not applied to the heat-sensitive portion, high-frequency leakage can be neglected between the metal tube of the heat-sensitive portion and the heating wall constituting the heating chamber, and a gap is provided between the heat-sensitive portion and direct contact. It can be installed without any trouble, the heat from the electric heater directly conducted through the heating wall is reduced, only the temperature in the heating chamber can be detected, and the temperature set regardless of the shape of the object to be heated Can be heated.

In addition, the metal tube is mounted on the heating wall without directly contacting the heating wall via an insulator.

Further, the heat from the electric heater directly conducted through the heating wall is further reduced, so that the temperature in the heating chamber can be detected and controlled more responsively, so that the finish as set and the stability during repeated heating can be achieved. A finished state is obtained.

[0011]

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

(Embodiment 1) FIG. 1 (a) is a cross-sectional view of a principal part showing the structure of a heat-sensitive part of a high-frequency heating apparatus with a heater according to Embodiment 1 of the present invention, and FIG. FIG. FIG. 2 is a side sectional view showing the entire apparatus according to the first embodiment of the present invention, and FIG. 3 is an air circuit diagram of a heating apparatus according to the first embodiment of the present invention.

In FIG. 2, an object 2 to be heated
The heating chamber 3 for heating is formed. A door 4 is provided on the front surface of the heating chamber 3 so as to be openable and closable so that the object to be heated 2 can enter and exit the heating chamber 3. An electric heating device serving as a heating means around an outer periphery of a heating wall forming the heating chamber 3;
A high frequency generator 15 and its supply means are provided.
In the present embodiment, a compartment 9 for housing a sheathed heater 6a, 6b and a blower fan 8 rotated by a motor 7 is provided at the rear of the rear wall 5 of the heating chamber, and air in the heating chamber is sucked from the center of the rear wall 5. After heating by the heat of the sheathed heaters 6a and 6b, the radiant heat is directly passed through the small hole group 11 on the upper portion of the heating wall upper wall 10 and the hot air circulation type heating device which blows out from the periphery of the rear wall 5 to the heating chamber 3. A radiant heating device is provided with glass tube heaters 12a and 12b that radiate red light to the object 2 to be heated.

A rotary antenna 14 rotatably supported by a motor 13 is disposed near the bottom wall of the heating wall, and the rotary antenna and a high frequency generator 15 provided outside the heating chamber 3 are provided.
The high frequency generated by the high frequency generator 15 is irradiated to the inside of the heating chamber 3 through the rotary antenna 14. A dielectric partition plate 18 is disposed near the upper portion of the rotary antenna 14, and a portion where the object 2 can be disposed and the rotary antenna 14 are disposed.
Are divided. Further, an operation panel 19 for controlling and operating these heating means and a control circuit 20 are provided on the upper part of the front surface of the main body 1.
As shown in FIG. 9, the configuration of the heating means for the object to be heated 2 and the setting of the heating temperature and the heating time can be freely set.

A heat-sensitive part 22 for controlling the temperature of the heating chamber 3 is provided at a part on the side wall 21 constituting the heating chamber 3 and between the object 2 and the electric heating apparatus. As shown in FIG. 1, the heat-sensitive part 22 is provided with a heat-sensitive element 24 in the vicinity of a sealed part of a metal cylinder 23 made of a stainless steel material having one end sealed, and this part is provided so as to protrude into the heating chamber 3. The heat sensitive part 22
Was covered with a metal cover 26 having a plurality of small holes 25 having a diameter of 3 mm on a surface facing the electric heating device. Metal tube 2
The inside of the heating chamber 3 is constituted by a substantially linear cylindrical shape. Further, a mounting plate 27 made of stainless steel is mounted on the metal cylinder 23 by pressing, and a part of the mounting plate 27 is fixed to the side wall 21 by screwing. An opening 28 is provided in the side wall 21 around the metal tube 23 so as not to come into direct contact with the metal tube 23 except for a portion necessary for fastening the mounting plate 27. The cover 26 is configured to be in contact with the side wall 21 at a position outside the outer periphery 29 of the mounting plate 27, so that the end surface of the opening 28 and the mounting screw portion are not exposed to the inside of the refrigerator, and high frequency is not applied. It is composed.
In FIG. 1, the metal cylinder 23 has a straight cylindrical shape. However, as another embodiment, the tip is bent in a range within the cover 26.
The length from the mounting plate 27 to the thermal element 24 may be increased. In the first embodiment, the material of the metal tube 23 is a stainless steel material having excellent corrosion resistance. However, for example, an aluminum material may be used in order to enhance the thermal response. On the contrary, the mounting plate 27 is made of stainless steel to suppress the thermal responsiveness, but may be made of another metal as appropriate according to the desired degree of responsiveness.

The thermosensitive element 2 of the thermosensitive part 22 having this configuration
Reference numeral 4 denotes a thermistor having a characteristic that the electric resistance value decreases as the temperature rises, and controls the temperature in the heating chamber 3 by the circuit configuration shown in FIG.

Next, the circuit and its operation will be described. FIG. 3 is a diagram showing an electric circuit of the entire device. The resistance value of the thermosensitive element 23, that is, the thermistor is taken into the control device 20. The control device 20 includes a microcomputer circuit 30. At least, the operator can select a heating unit, select a heating temperature,
An operation switch circuit 31 for setting a heating time, starting and stopping heating, an operation circuit 31 for notifying a user of a heating elapsed time, a temperature in a heating chamber, a heating state, an operation state, and the like, and an open / close state of a door 4. It has an input circuit such as a door signal switch 33 that detects and opens and closes in conjunction with it, and an output circuit for controlling each heating means.

The circuit constituting the heating means is similarly connected to a power source through a fuse 34 and a power switch 35 from a power source as shown in FIG. The sheath heaters 6a and 6b, which are heat sources of the hot air circulation type heating means, are connected in parallel, one of which is connected to the contact of the control relay 36 and the other of which is connected to the triac 37. The control relay 36 closes the circuit when the operator selects the heating means of the hot air circulation type, and allows the sheathed heaters 6a and 6b to be energized. The motor 7 connected in parallel rotates and sends air in the compartment 9 into the heating chamber 3. Triac 3
Reference numeral 7 denotes a circuit for interrupting the heater circuit in response to a signal from the control device 20. While the resistance value of the thermosensitive element 24 is higher than the set value, the control device 20 outputs a conduction signal to the triac 37, and the sheathed heaters 6a, 6b- Is turned on. At the moment when the resistance value of the thermal element 24 becomes lower than the set value, the control device 2
A value of 0 sends a cutoff signal to the triac 37 to stop energizing the sheathed heaters 6a and 6b. With this configuration, the temperature in the heating chamber 3 is controlled. Similarly, the glass tube heaters 12a and 12b, which are the heat sources of the radiant heating means, are connected in parallel, one of which is connected to the contact of the control relay 38 and the other of which is connected to the aforementioned triac 37. When the user selects the radiation type heating means, the control relay 38 closes the circuit and allows the glass tube heaters 12a and 12b to be energized. When energization starts, the glass tube heater glows red, and radiant heat is emitted into the heating chamber. The triac 37 receives a conduction signal from the control device 20 and supplies power to the glass tube heaters 12a and 12b while the resistance value of the thermosensitive element 23 is higher than the set value, as in the case of the hot air circulation type heating means. Glass tube heater 12a,
At the moment when the resistance value of the thermosensitive element 24 becomes lower than the set value due to the radiant heat of 12b, the control device 20 sends a cutoff signal to the triac 37 to stop energizing the glass tube heaters 12a and 12b. With this configuration, the amount of radiation in the heating chamber is controlled.

A high-frequency heating means is provided in parallel with such an electric heating means circuit. The transformer 3 is connected to the magnetron 15 as a high-frequency generator for high-frequency heating.
9, the input power of the drive power supply circuit including the capacitor 40 and the rectifier 41 is controlled by the relay 42. When the user places the article 2 to be heated in the heating chamber 3 and closes the door 4, the door signal switch 33 linked to opening and closing is closed, and the controller 2
High-frequency heating control at 0 is possible. At the same time, when the door switch 43 is closed, the high-frequency heating is selected, the heating time is set, and the operation related to the start of heating is performed, the relay 42 is closed, power is supplied to the transformer 39, and the magnetron 15
A high frequency is generated. The high-frequency energy is supplied to the rotating antenna 1 rotated by the motor 13 through the waveguide 17.
4 and is radiated from the rotating antenna 14 into the heating chamber.

The above three types of heating means are set individually in advance in an operation program of a microcomputer circuit 30 provided in the control device 20 so that they can be used alone or in combination according to the intention of the operator. They can be freely operated at the same time.

Next, the operation will be described. When high-frequency heating is first performed in the above-described configuration, the high-frequency waves generated in the heating chamber 3 are applied to the object 2 to be heated and simultaneously to the cover 26. No electric field is generated, and self-heating of the metal tube 23 due to high frequency is prevented. When the high-frequency frequency is 2450 MHz, a plurality of small holes having a diameter of 3 mm allow air in the heating chamber 3 to freely enter and exit, but almost no entry into the high-frequency cover occurs. Without considering the effect,
Optimal conditions for electric heating can be set. That is, conventionally, when the metal cylinder 23 protrudes from the heating side wall 21 by 10 mm or more, the influence of the electric field becomes remarkable. However, in the embodiment, any shape can be set as long as it is inside the cover.

Next, when electric heating is performed, for example, the heat generated by the sheathed heaters 6a and 6b causes the air in the compartment 9 to rise, and at the same time, the heating side wall 21 to rise. Conventionally, the heat of the side wall 21 directly reaches the metal tube 23 containing the heat-sensitive element 24 in the related art, but in the present invention, the side wall 21 around the metal tube 23 is made of metal except for the portion necessary for fastening the mounting plate 27. Since the opening 28 is provided so as not to come into direct contact with the cylinder 23, heat is not directly transmitted, and the influence of the temperature of the side wall 21 can be reduced. By doing so, the thermosensitive element 24 can detect the temperature of the air in the heating chamber 3. For example, even though the temperature of the heating wall surface 21 is rising, the temperature in the heating chamber 3 is reduced. If the temperature is low, the sheath heaters 6a and 6b are supposed to be energized. In the conventional method, the energization is interrupted due to the wall surface temperature, and the temperature in the heating chamber 3 becomes lower than the set value. The temperature in the chamber 3 is detected more accurately, and energization is promoted to control the temperature at the set temperature.

As described above, the metal tube 23 inside the cover 26
The shape of is not affected by the electric field no matter how it is configured.
For example, it is possible to extend or bend it for a long time.
4 is further extended, and the temperature control is performed in a state where the influence of the temperature of the side wall 21 is less. In the example, the case where the heating means of the hot air circulation type by the sheathed heaters 6a and 6b is selected has been described. However, the radiation type heating means for operating the glass tube heaters 12a and 12b similarly emits the heat inside the heating chamber 3 by the radiant heat. At the same time, the side wall 21 is also heated, and the operation of the heat sensitive part 22 is similar, and the present invention performs the same operation.

Further, conventionally, if foreign matter, for example, a piece of the object to be heated 2 adheres to the metal cylinder 23 or the vicinity of the root, the metal cylinder 23 is usually installed in a place where the user cannot easily reach it. In many cases. In this case, the piece of the article to be heated 2 is heated by the high frequency, and the temperature of the metal cylinder 23 is raised to a temperature equal to or higher than the temperature of the heating chamber. As a result, the temperature of the heating chamber is decreased. ,
By providing the cover 26, the piece of the article to be heated 2 is no longer attached to the metal cylinder 23, and even if the piece is operated in the attached state, the piece is not heated at a high frequency. It works so that the temperature of three chambers can be controlled.

(Embodiment 2) FIG. 4A is a cross-sectional view of a principal part showing a heat-sensitive portion 22 of a high-frequency heating apparatus with a heater according to Embodiment 2 of the present invention, and FIG. . The difference from the first embodiment is that a heat insulating material of an insulator is interposed on the mounting surface of the mounting plate 27, which is pressed against the metal cylinder 23, on the heating wall 21 constituting the heating chamber 3. The components having the same reference numerals as those in the first embodiment have the same structure, and the description will be omitted.

As in the first embodiment, a heat-sensitive element 24 is disposed near a sealed portion of a metal cylinder 23 having one end sealed, and this portion is provided so as to protrude into the heating chamber 3. A plurality of small holes 2 with a diameter of 3 mm on the surface facing the device
5 with a metal cover 26. Further, a stainless steel mounting plate 27 is attached to the metal cylinder 23 by pressing, and a part of the mounting plate 27 is fixed to the side wall 21 by screwing. The difference from the first embodiment is that the mounting plate 27 and the side wall 21 are not mounted in direct contact with each other, but the insulator 44, that is, a thickness of 3 m in the embodiment.
That is, it is mounted with an m-th silicon glass laminate interposed. As another embodiment, ceramics, heat-resistant plastic, or the like may be appropriately selected and used as the insulator 44. Further, in the other structure, as in the first embodiment, an opening 28 is provided on the side wall 21 around the metal cylinder 23 except for a part necessary for fastening the mounting plate 27 so as not to directly contact the metal cylinder 23. In the figure, the metal tube 23 is bent at its tip in a range within the cover 26 in order to further prevent heat propagation from the side wall 21, and the heat sensitive element 24 is
In this example, the length is made as long as possible, but it may be a straight cylindrical shape as in the first embodiment as appropriate according to the degree of necessity. Incidentally, as in the first embodiment, 23
Although a stainless steel material having excellent corrosion resistance is used as the material, for example, an aluminum material or the like may be used in order to enhance thermal response. On the other hand, the mounting plate 27 is made of stainless steel to suppress the thermal responsiveness, but may be made of another metal as appropriate according to the desired degree of responsiveness.

The effect in this case is that the side wall 21 at the time of electric heating is heated.
This means that the propagation of heat from the metal tube 23 to the metal tube 23 is extremely reduced. That is, since the heat of the side wall 21 propagates to the metal cylinder 23 only through the dielectric 44, the amount of propagation is extremely reduced as compared with the contact between metals. Therefore, the heat-sensing section 22 controls the temperature of the heating chamber 3 almost without being affected by the temperature of the side wall 21 as compared with the first embodiment. In addition, when performing the electric heating, the heating chamber may be kept at a set temperature in advance before the object to be heated 2 is installed in the heating chamber 3. Generally, this is referred to as preheating, and has an effect that the object to be heated 2 can be heated at a constant temperature, the finishing time is short, and the finished state is good. However,
In the conventional configuration of the heat-sensitive section 22, the wall temperature acts on the heat-sensitive section 22, and after preheating, the object to be heated 2 is placed in the heating chamber 3 and the electric heating means is energized even if the start of heating is designated. However, the object to be heated 2 is left at a temperature lower than the set temperature, so that the time required for finishing is extended, and it is not possible to finish at a stretch at a high temperature, and the finished state may be insufficient. Normally, the air in the heating chamber 3 which has risen to the set temperature by preheating, when the door 4 is opened and closed for the installation of the object 2 to be heated,
At one end, the temperature drops significantly from the set temperature. However, if the heat-sensitive portion 22 detects the temperature of the air in the refrigerator sensitively, the heating operation is started immediately after the door 4 is closed, whereas the temperature of the heating wall 21 is reduced. When the temperature is affected, the temperature of the air in the heating chamber 3 cannot be detected because the heat-sensitive portion 22 remains at the set temperature even if the door 4 is closed due to a difference in heat capacity. According to the first and second embodiments of the present invention, since the influence of the side wall 21 on the heat-sensitive portion 22 can be minimized, the electric heating device can be energized as soon as the door 4 is closed. In addition, the heating time can be reduced, and the finish can be satisfactory.

[0028]

As described above, according to the present invention, a change in the heating state due to a decrease in the temperature in the heating chamber due to an abnormal rise in the temperature of the heat-sensitive part during high-frequency heating and an influence of the temperature from the heating wall surface on the heat-sensitive part during electric heating. The unheated phenomenon can be eliminated. In particular, in the case of high-frequency heating, the antenna effect is lost, and even if the protrusion dimensions of the metal cylinder project into the refrigerator, there is no influence of self-heating, so that extremely accurate temperature control is possible.

Further, the temperature of the side wall and the temperature of the heat-sensitive portion can be separately detected, whereby the responsiveness to the temperature in the heating chamber can be further improved, and accurate temperature control can be performed.

Further, by providing a cover around the heat-sensitive part, a sharp projection into the heating chamber is eliminated, and
It enhances safety during cleaning and prevents breakage and breakdown due to collision of foreign matter, and also improves durability and usability.

In recent years, these problems have come to be noticed in recent years, in particular, in shortening the heating time and finishing state, which are required for this type of so-called commercial heating apparatus used in kitchens such as restaurants and hotels in the market. It addresses the issue of improvement. In the method of heating using both the electric heating and the high frequency heating output, it is possible to further increase the output by eliminating the influence of the heat sensitive portion on the high frequency. In addition, in this type of heating device that opens and closes the door frequently, the heating room temperature that decreases every time it is opened and closed is detected quickly, and the electric heating is controlled with good responsiveness, further shortening the heating time. This makes it possible to stabilize the repetitive finish and maintain a good state.

[Brief description of the drawings]

FIG. 1A is a side cross-sectional view of a main part showing a heat-sensitive portion of a high-frequency heating apparatus with a heater according to a first embodiment of the present invention. FIG. 1B is a cross-sectional view taken along the line AA ′ of FIG.

FIG. 2 is a sectional view of a main part showing the entire apparatus.

FIG. 3 is an electric circuit diagram according to the first embodiment of the present invention.

FIG. 4 (a) is a side cross-sectional view of a main part showing a heat-sensitive portion of a heating device with a heater according to a second embodiment of the present invention. (B) AA ′ cross-sectional view of FIG.

FIG. 5 is a side sectional view showing the configuration of a conventional device.

FIG. 6 is a cross-sectional view showing a heat-sensitive part of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Heating chamber 6a, 6b Sheath heater 15 Magnetron 21 Side wall 23 Metal cylinder 24 Thermal element 26 Cover 27 Mounting plate 28 Opening 44 Insulator

Claims (2)

[Claims] 1. A heating chamber is provided in a main body, and an apparatus for selectively enabling high-frequency heating and / or electric heating to the heating chamber at the same time is provided. For, while providing a heat-sensitive portion provided with a heat-sensitive element in the vicinity of a sealed portion of a metal cylinder having one end sealed and protruding into the heating chamber, the periphery of the heat-sensitive portion has air permeability,
A high-frequency heating device with a heater, wherein the high-frequency heating device is covered with a metal cover to which a high-frequency wave for heating does not enter, and further has a mounting structure in which the outer periphery of the metal tube of the heat-sensitive section does not directly contact the heating wall forming the heating chamber. 2. The high-frequency heating apparatus with a heater according to claim 1, wherein the metal cylinder is attached to the heating wall without directly contacting the heating wall via an insulator.