JP6722486B2 - High frequency heating device - Google Patents

Description

The present invention relates to a high-frequency heating device that applies a high-frequency electric field to food or the like to perform heat treatment, thawing treatment, or the like.

In the high-frequency heating device, a high-frequency high voltage is applied between two electrodes, and an object to be thawed as a dielectric is sandwiched therebetween to perform dielectric heating. FIG. 31 shows a defrosting device that performs defrosting processing by dielectric heating using high frequency. The defrosting device 1000 includes a heating chamber 1008 made of metal. In the heating chamber 1008, an upper electrode 1001, a lower electrode 1002, a bottom plate 1007, etc. are provided. The upper electrode 1001 and the lower electrode 1002 are each formed of a single metal plate and are arranged in parallel with each other. The bottom plate 1007 is disposed on the lower electrode 1002. The object to be defrosted 1003 is placed on the bottom plate 1007.

A high frequency oscillator 1005, a matching circuit 1006, and the like are provided outside the heating chamber 1008. The high frequency oscillator 1005 and the matching circuit 1006 are connected to the upper electrode 1001 and the lower electrode 1002 by wiring. A high frequency high voltage is supplied from a high frequency oscillator 1005 to the upper electrode 1001 and the lower electrode 1002. As a result, a high frequency electric field is generated between the upper electrode 1001 and the lower electrode 1002, the object to be defrosted 1003 is dielectrically heated, and the object to be defrosted 1003 is defrosted.

If an air gap exists between the upper electrode 1001 and the object to be defrosted 1003, the heating efficiency will decrease. Therefore, the thawing device 1000 is provided with an elevating mechanism 1004 for moving the upper electrode 1001 in the vertical direction. The elevating mechanism 1004 moves the upper electrode 1001 in the vertical direction according to the thickness of the object to be defrosted 1003.

Recently, it has been considered to improve the basic configuration of the above high-frequency heating device to provide a more practical defrosting device. For example, Patent Document 1 discloses a dielectric heating device in which a third electrode plate is arranged and the same potential as that of a fixed electrode is applied for the purpose of simplifying load matching or reducing energy loss.

Japanese Patent No. 3640621

As described above, the high-frequency heating device performs the defrosting process on the object to be defrosted by applying the high-frequency electric field to the object to be defrosted in the heating chamber. Therefore, a leakage electric field is generated outside the heating chamber. The value of the leakage electric field from the high-frequency heating device is limited by the regulation value specified by the Radio Law and the guideline value. Therefore, it is necessary to take measures to suppress the leakage electric field.

As a general measure against a leakage electric field, earth grounding of a metal housing is known. However, in the heating chamber, there is a possibility that a gap between the joints of the components that form the metal housing and an opening that is generated for structural reasons may be formed. In such a case, it becomes difficult to satisfy the above regulation value. Further, if the leakage electric field is to be suppressed only by the structure of the metal casing, it is necessary to take measures such as providing multiple shields with a metal, which causes a problem of increasing the size of the device. Therefore, a countermeasure against the leakage electric field by a method different from such a method is desired.

Therefore, it is an object of the present invention to provide a high-frequency heating device capable of suppressing a leakage electric field while suppressing an increase in size of the device.

The high-frequency heating device according to the first aspect of the present invention includes an upper electrode, a lower electrode disposed below the upper electrode, and a voltage applying unit that applies a high-frequency voltage between the upper electrode and the lower electrode. Is a high-frequency heating device equipped with. In this high frequency heating device, an auxiliary electrode is provided around the upper electrode. The voltage applying unit applies a voltage different from the high frequency voltage applied between the upper electrode and the lower electrode between the lower electrode and the auxiliary electrode.

The high-frequency heating device may further include a heating chamber that houses the upper electrode and the lower electrode, and the auxiliary electrode may be connected to the same potential as the heating chamber.

In the high-frequency heating device, the voltage applied between the lower electrode and the auxiliary electrode may have the same frequency and opposite phase as the high-frequency voltage applied between the upper electrode and the lower electrode. Good.

In the high-frequency heating device, the upper electrode has a plurality of rectangular first electrode plates, and the lower electrode has a plurality of rectangular second electrode plates, the first electrode plate And the second electrode plate has a long side and a short side, respectively, and the long side of the first electrode plate and the long side of the second electrode plate intersect each other. One electrode plate and the second electrode plate may be arranged. Further, it is preferable that the long side of the first electrode plate and the long side of the second electrode plate are substantially orthogonal to each other. Further, the plurality of rectangular first electrode plates or the plurality of rectangular second electrode plates may be connected to the matching circuit, respectively.

The high-frequency heating device may further include a second auxiliary electrode between the upper electrode and the lower electrode. The second auxiliary electrode has an opening in the center and is arranged at substantially the same position as the upper surface of the object to be heated, and between the lower electrode and the second auxiliary electrode, A voltage different from the high frequency voltage applied between the upper electrode and the lower electrode may be applied.

The high-frequency heating device further comprises a door for opening and closing a heating chamber accommodating the upper electrode and the lower electrode, and an elevating mechanism for moving the upper electrode in a vertical direction, and the elevating mechanism is for the door. The upper electrode may be raised in association with the opening operation.

The high-frequency heating device further includes a heating chamber door, and an opening operation of the heating chamber door and an ascending operation of the upper electrode are interlocked with each other, and a closing operation of the heating chamber door and a descending operation of the upper electrode are performed. May be interlocked.

The high-frequency heating device may further include a heating chamber door, and the opening operation of the heating chamber door and the lowering operation of the lower electrode may be interlocked.

The high-frequency heating device further includes a heating chamber door, the opening operation of the heating chamber door and the lowering operation of the lower electrode are interlocked, and the closing operation of the heating chamber door and the raising operation of the lower electrode are performed. May be interlocked.

As described above, the high-frequency heating device of the present invention is provided with the voltage applying unit that applies a voltage different from the high-frequency voltage applied between the upper electrode and the lower electrode between the lower electrode and the auxiliary electrode. ing. Therefore, the leakage electric field from the high-frequency heating device can be suppressed without changing the structure of the metal casing that constitutes the heating chamber of the high-frequency heating device.

It is a schematic diagram which shows the internal structure of the high frequency heating apparatus concerning the 1st Embodiment of this invention. It is a schematic diagram which shows the structure in the heating chamber of the high frequency heating apparatus concerning the 1st Embodiment of this invention. It is a circuit diagram which shows the internal structure of the matching circuit in the high frequency heating apparatus shown in FIG. It is a figure which shows the equivalent circuit structure between each electrode and the matching circuit in the high frequency heating apparatus shown in FIG. It is a figure which shows the circuit structure between each electrode and the matching circuit in the high frequency heating apparatus shown in FIG. It is a schematic diagram which shows the measurement position of a leak electric field in a high frequency heating apparatus. (A) is a graph which shows the result of having calculated the electric field value in the high frequency heating device which has an auxiliary electrode. (B) is a graph which shows the result of having calculated the electric field value in the high frequency heating device which does not have an auxiliary electrode. (C) is a schematic diagram which shows the position of the high frequency heating device corresponding to the horizontal axis of the graphs shown in (a) and (b). (A) And (b) is a figure which shows typically the relationship of the opening/closing operation of the door of a high frequency heating apparatus, and the raising/lowering operation of an upper electrode. It is a side view which shows the raising/lowering mechanism of the upper electrode with which the high frequency heating apparatus concerning the 1st Embodiment of this invention was equipped. It is a top view which shows the raising/lowering mechanism of the upper electrode with which the high frequency heating apparatus concerning the 1st Embodiment of this invention was equipped. It is a front view which shows the raising/lowering mechanism of the upper electrode with which the high frequency heating apparatus concerning the 1st Embodiment of this invention was equipped. It is a schematic diagram which shows the internal structure of the high frequency heating apparatus concerning the 2nd Embodiment of this invention. It is a figure which shows the equivalent circuit structure between each electrode and the matching circuit in the high frequency heating apparatus shown in FIG. It is a figure which shows the waveform (phase) of the voltage applied to the upper electrode and auxiliary electrode of the high frequency heating apparatus shown in FIG. (A) is a graph which shows the result of having calculated the electric field value in the high frequency heating device which applied the anti-phase voltage to the auxiliary electrode. (B) is a graph showing a result of calculating an electric field value in the high frequency heating device when the auxiliary electrode is set to the ground potential. (C) is a schematic diagram which shows the position of the high frequency heating device corresponding to the horizontal axis of the graphs shown in (a) and (b). It is a graph which shows the relationship between the voltage applied to an auxiliary electrode, and the peak value of a leakage electric field. It is a schematic diagram which shows the internal structure of the high frequency heating apparatus concerning the 3rd Embodiment of this invention. It is a schematic diagram which shows the structure in the heating chamber of the high frequency heating apparatus concerning the 3rd Embodiment of this invention. It is a figure which shows the equivalent circuit structure between the electrode and the matching circuit in the high frequency heating apparatus shown in FIG. It is a schematic diagram which shows an example of a structure of the electrode in the high frequency heating apparatus shown in FIG. It is a schematic diagram which shows the other example of a structure of the electrode in the high frequency heating apparatus shown in FIG. It is a schematic diagram which shows the internal structure of the high frequency heating apparatus concerning the 4th Embodiment of this invention. It is a figure which shows the equivalent circuit structure between the electrode and the matching circuit in the high frequency heating apparatus shown in FIG. It is a schematic diagram which shows an example of a structure of the electrode in the high frequency heating apparatus shown in FIG. (A) is a schematic diagram which shows the internal structure of the high frequency heating apparatus concerning the 5th Embodiment of this invention. (B) is a figure which shows the equivalent circuit structure between the electrode and the matching circuit in the high frequency heating apparatus shown in (a). It is a side view which shows the raising/lowering mechanism of the upper electrode with which the high frequency heating apparatus concerning the 6th Embodiment of this invention was equipped. It is a top view which shows the raising/lowering mechanism of the upper electrode with which the high frequency heating apparatus concerning the 6th Embodiment of this invention was equipped. It is a front view which shows the raising/lowering mechanism of the upper electrode with which the high frequency heating apparatus concerning the 6th Embodiment of this invention was equipped. It is a schematic diagram which shows the internal structure of the high frequency heating apparatus concerning reference embodiment of this invention. It is a schematic diagram which shows the internal structure of the high frequency heating apparatus concerning another reference form. It is a schematic diagram which shows the structure of the conventional defrosting apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are designated by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
(Schematic configuration of high-frequency heating device)
First, the schematic configuration of the high-frequency heating device 100 according to the present embodiment will be described with reference to FIGS. 1 and 2. The high-frequency heating device 100 of the present embodiment applies a high-frequency electric field to an object to be heated 3 such as food to perform heat treatment, thawing treatment, etc. on the object to be heated. The high frequency heating device 100 includes a heating chamber 8. The heating chamber 8 is formed of a metal housing.

As shown in FIG. 2, the heating chamber 8 is provided with an upper electrode 1, a lower electrode 2, a lifting mechanism 4, a bottom plate 7, an auxiliary electrode 11, a top plate 12, and the like. The upper electrode 1 and the lower electrode 2 are each composed of a plurality of metal plates, as will be described later. The upper electrode 1 and the lower electrode 2 are arranged so as to be parallel to each other. The bottom plate 7 is arranged above the lower electrode 2 and is in close contact with the lower electrode 2. The top plate 12 is arranged below the upper electrode 1 and is in close contact with the upper electrode 1. The auxiliary electrode 11 is arranged on the same surface as the upper electrode 1, and is arranged around the upper electrode 1. The upper electrode 1 and the auxiliary electrode 11 are insulated from each other.

The upper electrode 1 and the top plate 12 are connected to the lifting mechanism 4. The elevating mechanism 4 is equipped with a gear and a motor. As a result, the elevating mechanism 4 moves in the vertical direction. With the movement of the elevating mechanism 4, the upper electrode 1, the auxiliary electrode 11, and the top plate 12 connected to the elevating mechanism 4 can also be vertically moved. Thereby, the position of the upper electrode 1 can be changed according to the size of the article 3 to be heated during the heat treatment.

When the object 3 to be heated is heated or thawed using the high frequency heating device 100, the object 3 to be heated is placed on the bottom plate 7. Then, a high-frequency electric field is applied between the upper electrode 1 and the lower electrode 2 by a method described later to perform dielectric heating and thawing due to dielectric loss of the object to be heated 3.

(Structure of each electrode)
Next, a specific configuration of each electrode in the heating chamber 8 and a configuration of a voltage applying unit that applies a voltage to each electrode will be described with reference to FIG.

As shown in FIG. 1, the upper electrode 1 is composed of four rectangular (rectangular) first electrode plates 1a, 1c, 1b, and 1d. The lower electrode 2 is composed of four rectangular (rectangular) second electrode plates 2A, 2B, 2C, and 2D. The position where the long sides of the first electrode plates 1a, 1c, 1b, 1d and the long sides of the second electrode plates 2A, 2B, 2C, 2D are substantially orthogonal when viewed from above It is arranged in a relationship. The auxiliary electrode 11 is arranged so as to surround the four first electrode plates 1a, 1c, 1b, 1d.

Further, outside the heating chamber 8, a voltage application unit 10 for applying a voltage to each electrode is provided. The voltage applying unit 10 mainly includes a matching circuit 5, a high frequency oscillator 13, an amplifier (high frequency amplifier) 14, an upper electrode switching unit 15, and a lower electrode switching unit 16.

FIG. 3 shows a circuit configuration in the matching circuit 5. As shown in FIG. 3, the matching circuit 5 includes variable capacitors 5a and 5b, a variable coil 5c, and the like. As a result, the matching circuit 5 cancels the reactance of the capacitor composed of the upper electrode 1 and the lower electrode 2. Further, the matching circuit 5 can match the input impedance to the matching circuit 5 and the output impedance to the amplifier 14 by adjusting the values of the variable capacitors 5a and 5b and the variable coil 5c.

The high frequency oscillator 13 transmits a voltage signal of HF to VHF band frequency and supplies it to the amplifier 14. The amplifier 14 amplifies the voltage signal transmitted from the high frequency oscillator 13 to a desired power. The voltage signal amplified by the amplifier 14 is supplied to the capacitor formed by the upper electrode 1 and the lower electrode 2 through the matching circuit 5, the upper electrode switching unit 15 and the lower electrode switching unit 16. As a result, a high frequency electric field is generated between the upper electrode 1 and the lower electrode 2. Then, the object to be heated 3 placed between the upper electrode 1 and the lower electrode 2 is dielectrically heated.

The upper electrode switching unit 15 has a switch for supplying a voltage signal to be supplied to the upper electrode 1 to each of the four first electrode plates 1a, 1c, 1b and 1d. The lower electrode switching unit 16 has switches for connecting the wiring on the matching circuit 5 side and the four second electrode plates 2A, 2B, 2C, and 2D, respectively.

Moreover, as shown in FIG. 1, the heating chamber 8, the lower electrode 2, and the auxiliary electrode 11 are grounded. As a result, the heating chamber 8, the lower electrode 2, and the auxiliary electrode 11 have the same potential (specifically, the potential of 0V). On the other hand, a high frequency voltage is applied to the upper electrode 1 so as to have a V ⁺ potential, for example.

FIG. 4 shows an equivalent circuit composed of first electrode plates 1a, 1c, 1b, 1d forming the upper electrode 1 and second electrode plates 2A, 2B, 2C, 2D forming the lower electrode 2. Indicates. FIG. 4 shows a case where the switch for the first electrode plate 1a in the upper electrode switching unit 15 is in the ON state, and the switch for the second electrode plate 2A in the lower electrode switching unit 16 is in the ON state.

As shown in FIG. 4, the equivalent circuit includes an equivalent capacitor 18, an equivalent resistor 19, and an equivalent capacitor 20. The equivalent capacitor 18 is composed of a first electrode plate 1a on the upper electrode 1 side and a second electrode plate 2A on the lower electrode 2 side. The equivalent resistance 19 is composed of the dielectric loss of the object to be heated 3. The equivalent capacitor 20 is composed of the first electrode plate 1 a on the upper electrode 1 side and the auxiliary electrode 11. The equivalent capacitor 18 and the equivalent resistor 19 are connected in series. Further, the equivalent capacitor 18, the equivalent resistance 19 and the equivalent capacitor 20 are connected in parallel. Further, the second electrode plate 2A on the lower electrode 2 side and the auxiliary electrode 11 are grounded.

FIG. 5 shows the configuration of switches in the upper electrode switching unit 15 and the lower electrode switching unit 16. As shown in FIG. 5, the upper electrode switching unit 15 has a switch for supplying the voltage supplied to the upper electrode 1 to each of the four first electrode plates 1a, 1c, 1b, and 1d. doing. The lower electrode switching unit 16 has switches for connecting the wiring on the matching circuit 5 side and the four second electrode plates 2A, 2B, 2C, and 2D, respectively.

By turning on each switch provided in the upper electrode switching unit 15 and the lower electrode switching unit 16, the plurality of first electrode plates 1a, 1c, 1b, 1d and the plurality of second electrode plates 2A are formed. An electric field can be formed between 2B, 2C and 2D. Then, depending on which of the switches provided in the upper electrode switching unit 15 and the lower electrode switching unit 16 is in the ON state and which is in the OFF state, which region between the upper electrode 1 and the lower electrode 2 is selected. It is possible to select whether to form an electric field. Regarding the configuration in which the upper electrode 1 is divided into a plurality of electrode plates and the lower electrode 2 is divided into a plurality of electrode plates, the same configuration as in the sixth embodiment described later can be applied.

(Suppressing leakage electric field)
Next, suppression of the leakage electric field by the auxiliary electrode 11 will be described below with reference to FIGS. 6 and 7. In the conventional high-frequency heating device, the upper electrode and the lower electrode are surrounded by a heating chamber made of metal without any gap, and the heating chamber is grounded to prevent leakage electric field. However, there are cases in which the heating chamber has no choice but to be provided with openings or gaps for structural reasons. The present embodiment provides a high-frequency heating device capable of appropriately suppressing the leakage electric field in such a case.

For example, in the high frequency heating apparatus 100 of the present embodiment, as shown in FIG. 6, it is assumed that an opening 21 on the slit is provided on the side surface of the heating chamber 8. Then, FIG. 7A shows the result of calculating the electric field on the Z-Z′ axis of the outer surface of the heating chamber 8 by the difference equation on the plane 22 including the position where the opening 21 is formed. Note that FIG. 7B shows, as a comparison target, a result of calculating an electric field value in a high-frequency heating device having no auxiliary electrode. Further, FIG. 7C shows the position of the high frequency heating device corresponding to the horizontal axis of the graphs shown in FIGS. 7A and 7B. In FIGS. 7A and 7B, the electric field peak value in the case without the auxiliary electrode shown in FIG. 7B is set to 1 and the electric field value at each position is normalized and shown.

As shown in FIGS. 7A and 7B, at the position where the opening 21 is formed, the value of 1 when there is no auxiliary electrode is different from that of the auxiliary electrode 11 as in the high frequency heating device 100 of the present embodiment. When it was provided, the value was 0.27. From this result, it was confirmed that the electric field strength was reduced by providing the auxiliary electrode 11. Therefore, the auxiliary electrode 11 is effective in suppressing the leakage electric field.

(About the interlocking movement of the upper and lower electrodes and the opening/closing operation of the heating chamber door)
Next, the opening/closing operation of the door 42 provided in the heating chamber 8 of the high frequency heating device 100 of the present embodiment and the vertical movement of the upper electrode 1 will be described with reference to FIGS. 8 to 11. 8(a) and 8(b) schematically show the relationship between the opening/closing operation of the door of the high-frequency heating device and the lifting operation of the upper electrode. 9 to 11 show the structure of the lifting mechanism 4 for the upper electrode 1. Note that, for convenience of explanation, the surface on which the door 42 is arranged is referred to as the front surface of the high-frequency heating device 100. Then, when the high-frequency heating device 100 is placed in a state of being used, the surface located on the left side is the left side surface, the surface located on the right side is the right side surface, and the surface located on the rear side is based on the front surface. The back surface is defined as the upper surface, the upper surface is defined as the upper surface, and the lower surface is defined as the bottom surface.

Generally, in a high frequency heating device, if an air gap exists between the electrode and the object to be heated, the heating efficiency will be reduced. Therefore, some conventional high-frequency heating devices are provided with a mechanism for moving the electrodes up and down according to the thickness of the object to be heated. For example, Japanese Patent Laid-Open No. 2002-246165 includes an electrode distance varying unit 130 driven by a motor, and the distance between the electrode plates 108 and 109 can be changed according to the size of the object to be defrosted 121. A high frequency defroster is disclosed.

By the way, when thawing a frozen food or the like using a high-frequency heating device, in actual use, it is assumed that the door of the heating chamber is opened during the heat treatment to check the condition of the food. However, when the electrode is close to the food, the food is hidden by the electrode, and the state of the food cannot be visually confirmed. Therefore, when the operation of opening the heating chamber door is performed, for example, it is desired to perform a process of raising the upper electrode.

However, in the case of the configuration in which the upper electrode is raised by the motor, the control unit or the like in the apparatus detects that the operation of opening the heating chamber door has been performed, and then proceeds to the raising process of the upper electrode. Therefore, it takes time from when the door of the heating chamber is opened until the food is visible, and there is a problem that operability is poor.

Therefore, in the high-frequency heating device 100 according to this embodiment, the elevating mechanism 4 that moves the upper electrode 1 in the vertical direction can raise the upper electrode 1 in conjunction with the opening operation of the door 42. With this configuration, the upper electrode 1 rises mechanically in conjunction with the opening operation (opening operation) of the heating chamber door 42 (see FIG. 8B). Therefore, it is possible to quickly confirm the state of the food during heating and take out the food, and it is possible to improve the operability of the high-frequency heating device.

Further, in the high frequency heating device 100 of the present embodiment, as shown in FIG. 8A, the upper electrode 1 may descend mechanically in conjunction with the closing operation (closing operation) of the heating chamber door 42. As a result, the heating process can be started immediately after the door 42 is closed.

Subsequently, specific configurations of the lifting mechanism 4 and the door 42 will be described. The high frequency heating device 100 has a heating chamber 8 inside. A heating chamber door 42 that opens and closes the inside of the heating chamber 8 is attached (see FIG. 9). As described above, inside the heating chamber 8, the upper electrode 1, the lower electrode 2, the bottom plate 7, the auxiliary electrode 11, the top plate 12 and the like are provided. The upper electrode 1 can be moved up and down by an elevating mechanism 4 in order to improve heating efficiency.

For example, in the present embodiment, the dimensions (width×depth×height) of the heating chamber 8 can be set to 200×150×100 (mm), and the vertical height of the upper electrode 1 can be set to 55 (mm). 9 to 11, the high frequency power source (voltage applying unit 10) is not shown.

9 to 11 show a state in which the door 42 is closed. Here, the operation of each member when the door 42 is opened from the closed state to the 90 degree open state will be described. The lifting mechanism 4 includes an upper electrode support post 41, a spur gear 43, a spur gear 44, a bevel gear 45, a bevel gear 46, a bevel gear 47, a bevel gear 48, a pinion gear 49, a rack 51, a heating chamber door support 52, a shaft 53, and a shaft. 54, a shaft 55, a fixing fitting 56, and the like.

The door 42 and the spur gear 43 are fixed by a fixing fitting 56. When the door 42 is opened from the closed state to the 90 degree open state, the spur gear 43 accordingly rotates 90 degrees clockwise as viewed from the top surface. The spur gear 44 meshed with the spur gear 43 has the same number of teeth as the spur gear 43. Therefore, as the spur gear 43 rotates clockwise by 90 degrees, the spur gear 44 rotates counterclockwise by 90 degrees as viewed from above.

The spur gear 44 and the bevel gear 45 are attached to the same shaft 53. As a result, the bevel gear 45 rotates 90 degrees counterclockwise when viewed from the top surface as the spur gear 44 rotates. The bevel gear 46 meshes with the bevel gear 45. Further, the bevel gear 46 has 1/3 the number of teeth of the bevel gear 45. As a result, the bevel gear 46 rotates 270 degrees clockwise as viewed from the front surface (the front surface of the apparatus 100) as the bevel gear 45 rotates 90 degrees.

The bevel gear 47 is attached to the same shaft 54 as the bevel gear 46. Therefore, as the bevel gear 46 rotates, the bevel gear 47 rotates 270 degrees clockwise as viewed from the front. The bevel gear 48 has the same number of teeth as the bevel gear 47. Therefore, as bevel gear 47 rotates 270 degrees, it rotates 270 degrees clockwise as viewed from the left side surface of device 100.

The pinion gear 49 is attached to the same shaft 55 as the bevel gear 48. Therefore, as the bevel gear 48 rotates, the pinion gear 49 rotates 270 degrees clockwise as viewed from the left side surface. The rack 51 is attached to the upper electrode support column 41. Therefore, the rack 51 rises together with the upper electrode support column 41 and the upper electrode 1 as the pinion gear 49 rotates. For example, the module and the number of teeth of the pinion gear 49 can be set so that the rack 51 satisfies the elevation height 55 (mm) when the pinion gear 49 rotates 270 degrees. Here, the module is 1, and the number of teeth is 24. However, the present invention is not limited to this.

When the heating chamber door 42 is closed from the 90 degree open state to the closed state, the upper electrode 1 performs an operation opposite to the above-described movement, and descends by 55 (mm).

As described above, in the high-frequency heating device 100 of this embodiment, the opening/closing operation of the heating chamber door 42 and the lifting operation of the upper electrode 1 are linked. As a result, the upper electrode 1 is raised at the same time when the heating chamber door 42 is opened. Therefore, it is possible to more easily confirm the state of the object to be heated during the heating chamber processing, as compared with the configuration in which the electrodes are moved up and down by the motor. Further, according to this configuration, it is possible to improve the speed of the work of putting in and out of the object to be heated.

Further, when the shape of the object to be heated is constant, if the height of the upper electrode 1 is designed according to the thickness of the object to be heated, the actuator for lifting the electrode can be omitted. As a result, the structure can be simplified and a low-cost high-frequency heating device can be provided.

In the present embodiment, the configuration in which the distance between the upper electrode 1 and the lower electrode 2 can be changed by moving the upper electrode 1 in the vertical direction has been described, but in the present invention, the lower electrode 2 is moved in the vertical direction. The distance between the upper electrode 1 and the lower electrode 2 can be adjusted by moving them.

<Second Embodiment>
Then, the 2nd Embodiment of this invention is described. In the above-described first embodiment, the potential of the auxiliary electrode 11 is the same as that of the heating chamber 8 (specifically, the ground potential G). However, the present invention is not limited to such a configuration, and the auxiliary electrodes may have different potentials. In the second embodiment, a configuration will be described in which a voltage having a phase opposite to the voltage applied to the upper electrode is applied to the auxiliary electrode for suppressing the leakage electric field.

FIG. 12 shows a high-frequency heating device 200 according to the second embodiment of the present invention. The basic configuration of the high frequency heating device 200 is the same as that of the high frequency heating device 100 (see FIG. 1). Therefore, in the high-frequency heating device 200, members having the same structure and function as those of the high-frequency heating device 100 are designated by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 12, the high frequency heating device 200 includes an auxiliary electrode 211. In the first embodiment, the auxiliary electrode 11 is grounded. On the other hand, in the second embodiment, the auxiliary electrode 211 is not grounded. The auxiliary electrode 211 is connected to one electrode of the variable capacitor 233. The other electrode of the variable capacitor 233 is grounded and connected to the lower electrode 2 (that is, the second electrode plates 2A, 2B, 2C, 2D) via the lower electrode switching unit 16.

In FIG. 13, in the high-frequency heating device 200, first electrode plates 1a, 1c, 1b, 1d forming the upper electrode 1 and second electrode plates 2A, 2B, 2C, 2D forming the lower electrode 2 are shown. An equivalent circuit composed of is shown. FIG. 13 shows the case where the switch for the first electrode plate 1a in the upper electrode switching unit 15 is in the ON state, and the switch for the second electrode plate 2A in the lower electrode switching unit 16 is in the ON state.

As shown in FIG. 13, the equivalent circuit includes an equivalent capacitor 218, an equivalent resistor 219, a variable capacitor 233, and an equivalent capacitor 234. The equivalent capacitor 218 is composed of a first electrode plate 1a on the upper electrode 1 side and a second electrode plate 2A on the lower electrode 2 side. The equivalent resistance 219 is composed of the dielectric loss of the object to be heated 3. The equivalent capacitor 234 is composed of the second electrode plate 2A on the lower electrode 2 side and the auxiliary electrode 211.

The equivalent capacitor 218 and the equivalent resistor 219 are connected in series. The equivalent capacitor 218, the equivalent resistor 219, and the equivalent capacitor 234 are connected in series and are connected to the output of the matching circuit 5. Further, in order to adjust the voltage ratio of the auxiliary electrode 11 to the upper electrode 1 (for example, the first electrode plate 1a), the variable capacitor 233 is connected in parallel with the equivalent capacitor 234, and the lower electrode 2 (for example, the second electrode The electrode plate 2A) is grounded.

A voltage V ⁻ different from the voltage V ⁺ applied to the upper electrode 1 with respect to the lower electrode 2 (that is, the ground potential G) is applied to the auxiliary electrode 11. FIG. 14 shows an example of the phase V1 of the voltage V ⁺ applied between the upper electrode 1 and the lower electrode 2 and the phase V2 of the voltage V ⁻ applied between the auxiliary electrode 11 and the lower electrode 2. Indicates. As shown in this figure, the phase V2 of the voltage V ⁻ applied between the auxiliary electrode 11 and the lower electrode 2 is the same as the phase V1 of the voltage V ⁺ applied between the upper electrode 1 and the lower electrode 2. It has the same frequency but opposite phase. The voltage V ^- absolute value is smaller than the absolute value of the voltage V ^+.

Next, the suppression of the leakage electric field by the auxiliary electrode 211 will be described with reference to FIG. Here, similar to the first embodiment, it is assumed that the slit-shaped opening 21 is provided on the side surface of the heating chamber 8 of the high-frequency heating device 200 (see FIG. 6 ).

FIG. 15A shows the result of calculating the electric field on the Z-Z′ axis of the outer surface of the heating chamber 8 by the difference equation on the plane 22 including the position where the opening 21 is formed. Note that FIG. 15B shows, as a comparison target, the result of calculating the electric field value in the high-frequency heating device 100 of the first embodiment. Further, FIG. 15(c) shows the position of the high frequency heating device corresponding to the horizontal axis of the graphs shown in FIGS. 15(a) and 15(b). In FIGS. 15A and 15B, the electric field peak value in the case without the auxiliary electrode shown in FIG. 7B is set to 1, and the electric field value at each position is normalized and shown.

Note that FIG. 16 shows the results of evaluation using the voltage ratio of the upper electrode 1 and the auxiliary electrode 211 with respect to the lower electrode 2 as a parameter. The horizontal axis represents the ratio of the voltage applied to the auxiliary electrode 211 to the voltage applied to the upper electrode 1. As shown in FIG. 16, when the voltage such that the voltage ratio of the auxiliary electrode 211 to the upper electrode 1 is 0.1 is applied, the electric field value is the lowest. Therefore, in the analysis shown in FIG. 15, a reverse phase voltage having a voltage ratio of 0.1 to the upper electrode 1 is applied to the auxiliary electrode 211.

As shown in FIG. 15A, at the formation position of the opening 21 in the high-frequency heating device 200 of the present embodiment, the value 0.07 is obtained as compared with the value 1 in the case without the auxiliary electrode (see FIG. 7B). Became. As shown in FIG. 15B, the measurement result of the comparative high-frequency heating apparatus 100 was a value of 0.27 as compared with the value of 1 without the auxiliary electrode (see FIG. 7B). From this result, it was confirmed that by providing the auxiliary electrode 211, the electric field strength was further reduced as compared with the case of the first embodiment. Therefore, the auxiliary electrode 211 is more effective in suppressing the leakage electric field.

Further, in the high frequency heating device 200 of the present embodiment, it is possible to control the voltage ratio of the upper electrode 1 and the auxiliary electrode 11 to the lower electrode 2 by adjusting the capacitance of the variable capacitor 233. Therefore, the voltage ratio of the upper electrode 1 and the auxiliary electrode 11 to the lower electrode 2 is controlled according to the vertical position of the top plate 12 (that is, the relative position between the upper electrode 1 and the auxiliary electrode 11 and the opening 21). Therefore, it is possible to suppress the leakage electric field according to the usage conditions.

<Third Embodiment>
Subsequently, a third embodiment of the present invention will be described. In the above-described first and second embodiments, the configuration in which the upper electrode 1 and the lower electrode 2 are each divided into a plurality of rectangular electrodes has been described. However, the present invention is not limited to such a configuration. Therefore, in the third embodiment, a configuration in which the upper electrode 1 and the lower electrode 2 are each formed of one rectangular metal plate will be described.

Further, in the third embodiment, a configuration example further including a second auxiliary electrode different from the auxiliary electrode 11 for suppressing the leakage electric field will be described. The second auxiliary electrode is provided for the purpose of heating the object to be heated more uniformly.

There has been a problem that when a frozen food or the like is thawed using a high-frequency heating device, high-frequency energy is concentrated on the ridges of the food, resulting in overheating of the outer circumference of the food. In order to solve this problem, for example, it has been considered that a plurality of counter electrodes having different sizes are sequentially used during the thawing process to suppress deterioration of the quality of the heated object during the thawing process.

However, the method of selectively using electrodes having different dimensions complicates the lifting mechanism of the electrodes. Also. With the above measures, there is a certain limit to the size of the object to be heated.

Therefore, the third embodiment provides a high-frequency heating device capable of heating an object to be heated more uniformly while suppressing the elevation function from being complicated. 17 and 18 show a high-frequency heating device 300 according to the third embodiment. The basic configuration of the high frequency heating device 300 is the same as that of the high frequency heating device 100 (see FIG. 1). Therefore, in the high-frequency heating device 300, members having the same structure and function as those of the high-frequency heating device 100 are designated by the same reference numerals, and description thereof will be omitted.

The high frequency heating device 300 includes a heating chamber 8. As shown in FIG. 18, inside the heating chamber 8, an upper electrode 1, a lower electrode 2, a lifting mechanism 4, a bottom plate 7, an auxiliary electrode 11, a top plate 12, a second auxiliary electrode 301, etc. are provided. ing. The upper electrode 1 and the lower electrode 2 are each composed of a single metal plate. The upper electrode 1 and the lower electrode 2 are arranged so as to be parallel to each other. The auxiliary electrode 11 is arranged on the same surface as the upper electrode 1, and is arranged around the upper electrode 1. The upper electrode 1 and the auxiliary electrode 11 are insulated from each other.

The second auxiliary electrode 301 is arranged between the upper electrode 1 and the lower electrode 2. The second auxiliary electrode 301 is formed of a single rectangular metal plate. Then, the second auxiliary electrode 301 has a rectangular opening 301a in the central portion. As shown in FIG. 18, when the object 3 to be heated is arranged between the upper electrode 1 and the lower electrode 2, the second auxiliary electrode 301 is located at substantially the same position as the position of the upper surface of the object 3 to be heated. Thus, the vertical position is set. Such position adjustment of the second auxiliary electrode 301 can be performed by a position adjusting mechanism (not shown).

Further, outside the heating chamber 8, a voltage application unit 310 for applying a voltage to each electrode is provided. The voltage application unit 310 mainly includes a matching circuit 5, a high frequency oscillator 13, an amplifier (high frequency amplifier) 14, a second matching circuit 302, an amplifier (high frequency amplifier) 303, and a phase shifter 304. As shown in FIG. 17, in the voltage application unit 310 of the present embodiment, the high frequency voltage signal from the high frequency oscillator 13 is mainly transmitted to the upper electrode 1 side and the second auxiliary electrode 301 side, respectively. ..

In the voltage application unit 310, the signal transmission circuit to the upper electrode 1 side includes the matching circuit 5 and the amplifier (high frequency amplifier) 14. The same configurations as those in the first embodiment can be applied to these. In addition, as shown in FIG. 17, the heating chamber 8, the lower electrode 2, and the auxiliary electrode 11 are grounded. As a result, the heating chamber 8, the lower electrode 2, and the auxiliary electrode 11 have the same potential (specifically, the potential of 0V). On the other hand, a high frequency voltage is applied to the upper electrode 1 so as to have a V ⁺ potential, for example. As a result, the potential difference between the upper electrode 1 and the lower electrode 2 becomes V ⁺ .

In the voltage application unit 310, the signal transmission circuit to the second auxiliary electrode 301 side includes the second matching circuit 302, the amplifier 303, and the phase shifter 304. The second matching circuit 302 can match the input impedance to the second matching circuit 302 and the output impedance to the amplifier 14. The amplifier 303 amplifies the voltage signal transmitted from the high frequency oscillator 13 to a desired power. The voltage signal amplified by the amplifier 303 passes through the second matching circuit 302 and is supplied to the equivalent capacitor 322 formed by the second auxiliary electrode 301 and the lower electrode 2 (see FIG. 19). Thereby, for example, the voltage V″ is applied between the second auxiliary electrode 301 and the lower electrode 2. The phase shifter 304 changes the phase of the voltage signal transmitted from the high frequency oscillator 13. ..

FIG. 19 shows an equivalent circuit composed of the upper electrode 1, the lower electrode 2, the auxiliary electrode 11, and the second auxiliary electrode 301. The equivalent circuit includes an equivalent capacitor 318, an equivalent resistor 319, an equivalent capacitor 320, an equivalent capacitor 321, and an equivalent capacitor 322. The equivalent capacitor 318 is composed of the upper electrode 1 and the lower electrode 2. The equivalent resistance 319 is composed of the dielectric loss of the object to be heated 3. The equivalent capacitor 320 is composed of the upper electrode 1 and the auxiliary electrode 11. The equivalent capacitor 321 includes the upper electrode 1 and the second auxiliary electrode 301. The equivalent capacitor 322 includes the lower electrode 2 and the second auxiliary electrode 301.

The equivalent capacitor 318 and the equivalent resistor 319 are connected in series. The equivalent capacitor 321 and the equivalent capacitor 322 are connected in series. Further, the equivalent capacitor 318 and the equivalent resistor 319, the equivalent capacitor 320, the equivalent capacitor 321 and the equivalent capacitor 322 are connected in parallel. Further, the lower electrode 2 and the auxiliary electrode 11 are grounded. As a result, the lower electrode 2 and the auxiliary electrode 11 have the same potential (specifically, the potential of 0V). On the other hand, a high frequency voltage is applied to the upper electrode 1 so as to have a V ⁺ potential, for example. Further, a high frequency voltage is applied to the second auxiliary electrode 301 so as to have a potential of V″, for example.

In the high-frequency heating device 300 of the present embodiment, by applying a voltage different from the voltage applied to the upper electrode 1 to the second auxiliary electrode 301, electric field concentration on the outer periphery of the object to be heated 3 is relaxed. .. This point will be described with reference to FIG.

FIG. 20 shows a high frequency voltage applied to the upper electrode 1, the lower electrode 2, and the second auxiliary electrode 301 through the matching circuits 5 and 302. Further, the distance between the upper electrode 1 and the lower electrode 2 is indicated by L, and the distance between the lower electrode 2 and the second auxiliary electrode 301 is indicated by d.

In the case of a high-frequency heating device in which the second auxiliary electrode 301 is not provided, if there is a space between the upper electrode 1 and the upper end of the heated object 3, the physical properties of the heated object (dielectric constant ε ₀ ·ε _r ) And the dielectric constant of the space cause a potential difference in the horizontal direction. For example, when the upper electrode 1, the lower electrode 2, and the object to be heated 3 are arranged at the distances L and d as shown in FIG. 20, the potential V′ of the space at the distance d from the lower electrode 2 is , V′=V·d/L, while the potential V″ of the upper surface of the object to be heated 3 becomes V″<V·d/L. That is, the potential difference in the horizontal direction is (V′−V″).

Due to this potential difference in the horizontal direction, electric field concentration occurs at the peripheral portion of the upper surface of the object to be heated. As a result, the peripheral portion of the upper surface of the object to be heated 3 may be heated more intensively than other portions, and uneven heating may occur.

On the other hand, in the high-frequency heating device 300 of the present embodiment, as shown in FIG. 20, the second auxiliary is provided at substantially the same position as the upper surface of the object 3 to be heated (that is, at the position d from the lower electrode 2). An electrode 301 is provided. Then, a voltage is applied to the second auxiliary electrode 301 so that the potential difference between the lower electrode 2 and the second auxiliary electrode 301 becomes V″. Therefore, it is possible to reduce the potential difference that occurs in 1. Therefore, it is possible to suppress uneven heating of the object to be heated 3.

The value of the voltage applied to the second auxiliary electrode 301 is preferably substantially the same as the potential of the upper surface of the object to be heated 3. Here, the potential of the upper surface of the object to be heated 3 is the height of the object to be heated 3 (that is, the interval d), the distance between the object to be heated 3 and the upper electrode 1 (that is, Ld), and the object to be heated. It changes depending on the physical properties of 3 (relative permittivity). Therefore, it is preferable that the potential V″ given to the second auxiliary electrode 301 can be changed based on these conditions. In the present embodiment, the amplifier (high frequency amplifier) 303 changes the value of the potential V″. It functions as a voltage adjusting unit.

The height of the object to be heated 3 also changes depending on the type of the object to be heated 3. Therefore, it is preferable that the distance d of the second auxiliary electrode 301 can be changed by the position adjusting mechanism. Further, the second auxiliary electrode 301 may be configured to move up and down together with the upper electrode 1. FIG. 21 shows an example of a configuration in which the second auxiliary electrode 301 and the upper electrode 1 move up and down together.

As shown in FIG. 21, the second auxiliary electrode 301 is connected to the upper electrode 1 by the support body 333. The upper electrode 1 can be moved in the vertical direction by the lifting mechanism 4. Since the second auxiliary electrode 301 and the upper electrode 1 are fixed by the same support 333, the second auxiliary electrode 301 and the upper electrode 1 can move up and down together. This eliminates the need to provide a position adjusting mechanism dedicated to the second auxiliary electrode 301.

As described above, according to the high frequency heating device 300 of the present embodiment, it is possible to suppress heating unevenness of the object to be heated 3 and perform higher quality heat treatment. In addition, it is possible to provide a general-purpose high-frequency heating device that can handle heat treatment and thawing treatment of various foods of different types and sizes.

As described above, in the high-frequency heating device of this embodiment, the lower electrode is set to the ground potential, and the second auxiliary electrode is provided between the upper electrode and the lower electrode. The second auxiliary electrode has a shape surrounding the upper surface of the object to be heated. Then, the voltage application unit applies a voltage different from the high frequency voltage applied between the lower electrode and the upper electrode between the lower electrode and the second auxiliary electrode.

In the above high-frequency heating device, the voltage application unit may be provided with a voltage adjustment unit that adjusts the voltage applied to the second auxiliary electrode according to the physical properties and size of the object to be heated. Further, the voltage adjustment unit may be a variable capacitor.

Further, in the above high-frequency heating device, the upper electrode and the auxiliary electrode may be fixed to the same support. Further, the support may be able to move up and down.

<Fourth Embodiment>
In the third embodiment described above, the amplifier (high-frequency amplifier) 303 connected to the high-frequency power source (high-frequency oscillator 13) is used as the voltage adjusting unit that adjusts the voltage applied to the second auxiliary electrode. However, the present invention is not limited to this configuration. Therefore, in the fourth embodiment, as another example of the voltage adjusting unit, a configuration using a variable capacitor as the voltage adjusting unit will be described.

FIG. 22 shows a high-frequency heating device 400 according to the fourth embodiment. The basic configuration of the high frequency heating device 400 is the same as that of the high frequency heating device 300 (see FIG. 17). Therefore, in the high-frequency heating device 400, members having the same structure and function as those of the high-frequency heating device 300 are designated by the same reference numerals, and description thereof will be omitted.

A voltage applying unit 10 for applying a voltage to each electrode is provided outside the heating chamber 8. The voltage applying unit 10 may have the same configuration as the voltage applying unit included in the high-frequency heating device 100 of the first embodiment. In the high frequency heating device 400, the variable capacitor 402 is provided between the second auxiliary electrode 401 and the lower electrode 2. By adjusting the capacitance of the variable capacitor 402, for example, a voltage V″ can be applied between the second auxiliary electrode 401 and the lower electrode 2. By this, the second auxiliary electrode 401 is supplied with a power source ( That is, it is not necessary to connect to the high frequency oscillator 13).

FIG. 23 shows an equivalent circuit composed of the upper electrode 1, the lower electrode 2, the auxiliary electrode 11, and the second auxiliary electrode 401. The equivalent circuit includes an equivalent capacitor 418, an equivalent resistor 419, an equivalent capacitor 420, an equivalent capacitor 421, an equivalent capacitor 422, and a variable capacitor 402. For the equivalent capacitor 418, the equivalent resistor 419, and the equivalent capacitor 420, the same configurations as those of the high frequency heating device 300 of the third embodiment can be applied.

The equivalent capacitor 421 is composed of the upper electrode 1 and the second auxiliary electrode 401. The equivalent capacitor 422 includes the lower electrode 2 and the second auxiliary electrode 401. The equivalent capacitor 421 and the equivalent capacitor 422 are connected in series. Further, the equivalent capacitor 422 and the variable capacitor 402 are connected in parallel. Further, the lower electrode 2 and the auxiliary electrode 11 are grounded.

As a result, the lower electrode 2 and the auxiliary electrode 11 have the same potential (specifically, the potential of 0V). On the other hand, a high frequency voltage is applied to the upper electrode 1 so as to have a V ⁺ potential, for example. The variable capacitor 402 adjusts, for example, the potential difference V″ between the second auxiliary electrode 401 and the lower electrode 2 (see FIG. 24).

As described above, in the high frequency heating device 400 of the present embodiment, the variable capacitor 402 is used to adjust the potential of the second auxiliary electrode 401. Thereby, electric field concentration on the peripheral portion of the upper surface of the object to be heated 3 can be relaxed without using the power supply for the second auxiliary electrode.

<Fifth Embodiment>
Subsequently, a fifth embodiment of the present invention will be described. In the above-described first and second embodiments, the configuration in which the upper electrode 1 and the lower electrode 2 are each divided into a plurality of rectangular electrodes has been described. However, the present invention is not limited to such a configuration. Therefore, in the fifth embodiment, a configuration in which the upper electrode 501 and the lower electrode 502 are each formed of one rectangular metal plate will be described.

FIG. 25A shows a high frequency heating device 500 according to the fifth embodiment. The basic configuration of the high frequency heating device 500 is the same as that of the high frequency heating device 100 (see FIG. 1). Therefore, in the high-frequency heating device 500, members having the same structure and function as those of the high-frequency heating device 100 are designated by the same reference numerals, and description thereof will be omitted.

The high frequency heating device 500 includes a heating chamber 8. As shown in FIG. 25, inside the heating chamber 8, mainly, an upper electrode 501, a lower electrode 502, a lifting mechanism (not shown), a bottom plate (not shown), an auxiliary electrode 11, a top plate (see FIG. (Not shown). The upper electrode 501 and the lower electrode 502 are each composed of a single metal plate. The upper electrode 501 and the lower electrode 502 are arranged so as to be parallel to each other. The auxiliary electrode 11 is arranged on the same surface as the upper electrode 1, and is arranged around the upper electrode 501. The upper electrode 501 and the auxiliary electrode 11 are insulated from each other.

Further, outside the heating chamber 8, a voltage application unit 10 for applying a voltage to each electrode is provided. The voltage applying unit 10 mainly includes a matching circuit 5, a high frequency oscillator 13, and an amplifier (high frequency amplifier) 14.

FIG. 25B shows an equivalent circuit composed of the upper electrode 501, the lower electrode 502, and the auxiliary electrode 11. The equivalent circuit includes an equivalent capacitor 18, an equivalent resistor 19 and an equivalent capacitor 20. The equivalent capacitor 18 is composed of an upper electrode 501 and a lower electrode 502. The equivalent resistance 19 is composed of the dielectric loss of the object to be heated 3. The equivalent capacitor 20 includes an upper electrode 501 and an auxiliary electrode 11.

The equivalent capacitor 18 and the equivalent resistor 19 are connected in series. Further, the equivalent capacitor 18, the equivalent resistance 19 and the equivalent capacitor 20 are connected in parallel. Further, the lower electrode 502 and the auxiliary electrode 11 are grounded.

Further, as shown in FIG. 25(a), the heating chamber 8 is grounded. As a result, the heating chamber 8, the lower electrode 502, and the auxiliary electrode 11 have the same potential (specifically, the potential of 0V). On the other hand, for example, a high frequency voltage is applied to the upper electrode 501 so as to have a V ⁺ potential.

As described above, the high frequency heating device 500 of the present embodiment has the auxiliary electrode 11. Accordingly, like the high frequency heating device 100 of the first embodiment, even when a gap such as an opening is formed in the heating chamber 8, the electric field value in the gap can be reduced (see FIG. 7). ). Therefore, the leakage electric field from the high frequency heating device 500 can be suppressed.

<Sixth Embodiment>
Subsequently, a sixth embodiment of the present invention will be described. The high frequency heating apparatus 600 according to the sixth embodiment is different from the first embodiment in the interlocking mechanism of the vertical movement of the upper electrode and the opening/closing operation of the heating chamber door. For other configurations, the same configurations as those of the first embodiment can be applied. Therefore, in the present embodiment, only the points different from the first embodiment will be described.

26 to 28 show the configuration of the high-frequency heating device 600 according to the sixth embodiment. In particular, these drawings show the configuration of the lifting mechanism 604 for the upper electrode 1. For convenience of explanation, the surface on which the door 42 is arranged is referred to as the front surface of the high-frequency heating device 600. Then, when the high-frequency heating device 600 is placed in a state of use, with the front surface as a reference, the surface located on the left side is the left side surface, the surface located on the right side is the right side surface, and the surface located on the rear side is The back surface is defined as the upper surface, the upper surface is defined as the upper surface, and the lower surface is defined as the bottom surface.

The basic structure of the lifting mechanism 604 is the same as the lifting mechanism 4 of the first embodiment. Therefore, in the elevating mechanism 604, members corresponding to those of the elevating mechanism 4 are designated by the same reference numerals, and description thereof will be omitted.

The elevating mechanism 604 differs from the elevating mechanism 4 in that the one-way clutch 621 and the shaft 622 are connected between the shaft 55 and the pinion gear 49, and the shaft 55 is extended to the right side of the pinion gear 49 so that This is the point where the one-way clutch 625, the shaft 623, and the motor 624 are connected (see FIGS. 27 and 28).

The one-way clutch 621 transmits to the shaft 622 only the rotation direction of the rotation of the shaft 55 when the heating chamber door 42 shifts from the closed state to the open state. Thereby, when the heating chamber door 42 shifts from the closed state to the open state, the upper electrode 1 is raised. On the other hand, when the heating chamber door 42 shifts from the open state to the closed state, the upper electrode 1 does not move.

The one-way clutch 625 transmits the rotation of the shaft 623 to the shaft 622 only when the motor 624 rotates in the direction of lowering the upper electrode 1 among the rotations of the shaft 623. This allows the motor 624 to lower the upper electrode 1. In addition, the motor 624 does not interfere with the operation of raising the upper electrode 1 by the heating chamber door 42.

According to the above configuration, the lowering operation of the upper electrode 1 can be performed by the motor 624. Therefore, the stop position when the upper electrode 1 descends can be adjusted by the thickness of the object to be heated 3. Thereby, the heating efficiency of the high frequency heating device can be further improved.

In the present embodiment, the configuration in which the distance between the upper electrode 1 and the lower electrode 2 can be changed by moving the upper electrode 1 in the vertical direction has been described, but in the present invention, the lower electrode 2 is moved in the vertical direction. The distance between the upper electrode 1 and the lower electrode 2 can be adjusted by moving them.

<Reference form>
Then, the form used as a reference of the present invention is explained. Generally, in a high frequency heating device, if an air gap exists between the electrode and the object to be heated, the heating efficiency will be reduced. Therefore, some conventional high-frequency heating devices are provided with a mechanism for moving the electrodes up and down according to the thickness of the object to be heated. For example, Japanese Patent Laid-Open No. 2002-246165 includes an electrode distance varying unit 130 driven by a motor, and the distance between the electrode plates 108 and 109 can be changed according to the size of the object to be defrosted 121. A high frequency defroster is disclosed.

By the way, in particular, an object to be heated (object to be thawed) such as frozen food is not homogeneous in composition, and the thickness of each part is not constant. Dielectric losses are different due to different food compositions. As a result, the amount of heat generated by the high-frequency electric field varies depending on the composition of the object to be heated, which leads to heating unevenness (unevenness of thawing). Further, when the size of the air gap is different due to the difference in the thickness depending on the portion, there occurs a phenomenon that a portion with a large air gap is difficult to be heated and a portion with a small air gap is easily heated. As a result, the amount of heat generated varies depending on the part of the object to be heated, which leads to uneven heating.

Therefore, in the patent document (JP-A-5-41971), a plurality of electrode pairs are installed in the heating chamber and the heating time is individually set for each electrode pair. This suppresses uneven heating of the object to be heated, which has a non-uniform composition or thickness.

However, if the number of heating zones is increased in order to finely heat the part to be heated, as many electrode pairs as the number of heating zones are required. For example, FIG. 30 shows a high-frequency heating device 900 in which an upper electrode 901 and a lower electrode 902 are divided into four vertically and horizontally (X direction and Y direction). The high-frequency heating device 900 includes an upper electrode 901, a lower electrode 902, a voltage application unit 910, an upper electrode switching unit 903, a lower electrode switching unit 909, and the like. The voltage application unit 910 includes a high frequency oscillator 906, an amplifier (high frequency amplifier) 907, and a matching circuit 908.

The upper electrode 901 is divided into 16 first electrode plates 11U to 44U. The lower electrode 902 is divided into 16 second electrode plates 11L to 44L so as to form a pair with the 16 first electrode plates 11U to 44U. Thus, the high frequency heating device 900 requires a combination of 16 electrode plates to form 16 heating zones.

Further, in order to supply high frequency power to each electrode, a power line 911 is required for each electrode plate from the upper electrode switching unit 903 and the lower electrode switching unit 909. Therefore, the device configuration becomes complicated. Further, when this configuration is combined with a configuration in which an electrode is moved up and down as in the patent document (Japanese Patent Laid-Open No. 2002-246165), there is a problem that the device becomes more complicated and larger.

Therefore, the present embodiment provides a high-frequency heating device 700 capable of suppressing heating unevenness while suppressing the device from becoming complicated. FIG. 29 shows the configuration of the high-frequency heating device 700 according to this reference embodiment.

The high-frequency heating device 700 includes an upper electrode 701, a lower electrode 702, a voltage application unit 710, an upper electrode switching unit 703, a lower electrode switching unit 709, and the like. The voltage application unit 710 includes a high frequency oscillator 706, an amplifier (high frequency amplifier) 707, and a matching circuit 708.

In the high frequency heating device 700, the upper electrode 701 is composed of four rectangular (rectangular) first electrode plates A, B, C, and D. Further, in the high frequency heating device 700, the lower electrode 702 is composed of four rectangular (rectangular) second electrode plates E, F, G, and H. The first electrode plates A, B, C, and D are connected to the upper electrode switching unit 703 by a power line 711, respectively. The second electrode plates E, F, G, and H are connected to the lower electrode switching unit 709 by a power line 711, respectively. This point is the same as the configuration of the high-frequency heating device 100 according to the first embodiment. However, the high frequency heating device 700 is not provided with the auxiliary electrode 11.

Then, when viewed from above the upper electrode 701, the long sides of the first electrode plates A, B, C, D and the long sides of the second electrode plates E, F, G, H are substantially orthogonal to each other. They are arranged in such a positional relationship that In this reference embodiment, both the upper electrode 701 and the lower electrode 702 are divided into four electrodes. Also, the long side direction of the first electrode plates A, B, C, D of the upper electrode 701 is the Y axis, and the long side direction of the second electrode plates E, F, G, H of the lower electrode 702 is the X axis. I am trying. However, the division number, shape, and arrangement of each electrode plate are not limited to this.

In the high frequency heating device 700, the number of heating zones is represented by the product of the number of divisions of the upper electrode 701 and the number of divisions of the lower electrode 702. When heating an arbitrary portion of the object to be heated, a high frequency voltage is applied between the first electrode plate and the second electrode plate above and below the area of the portion to be heated. A high frequency electric field is generated in a region where the projected areas of the upper electrode 701 and the lower electrode 702 overlap with each other in the Z-axis direction of the heated region. Then, the object to be heated located in the area is dielectrically heated.

For example, in FIG. 29, the number of divisions of the upper electrode 701 is 4, the number of divisions of the lower electrode 702 is 4, and the number of heating areas is 16. To heat the object to be heated in the X4Y4 area shown in FIG. 29, the upper electrode switching unit 703 connects the first electrode plate D to the voltage applying unit 710, and the lower electrode switching unit 709 grounds the lower electrode H. Connect to potential G. As a result, a high frequency electric field is generated in the area X4Y4 where the projected areas of the upper electrode 701 and the lower electrode 702 overlap with each other in the Z-axis direction of the area to be heated. As a result, the object to be heated located in the area X4Y4 is dielectrically heated.

According to the above configuration, the number of electrode pairs can be reduced and the number of power lines connected to the electrodes can be reduced even if the number of heating zones in the heating chamber is increased. As a result, it is possible to prevent the apparatus from becoming complicated and large.

As another form, the matching circuit 708 may be provided between each of the first electrode plates A, B, C, D and the upper electrode switching unit 703. In this case, a power detection circuit may be arranged between each matching circuit 708 and the upper electrode switching unit 703. By adopting such a configuration, the voltage can be adjusted for each zone when simultaneously heating a plurality of zones. As a result, finer heating adjustment can be performed.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope. Further, configurations obtained by combining the configurations of the different embodiments described in the present specification are also included in the scope of the present invention.

1: Upper electrodes 1a to 1d: First electrode plate 2: Lower electrodes 2A to 2D: Second electrode plate 4: Elevating mechanism 8: Heating chamber 10: Voltage applying unit 11: Auxiliary electrode 42: (of heating chamber) Door 301: second auxiliary electrode

Claims (6)

An upper electrode,
A lower electrode disposed below the upper electrode,
A high-frequency heating device comprising a voltage applying unit that applies a high-frequency voltage between the upper electrode and the lower electrode,
An auxiliary electrode is provided around the upper electrode,
The voltage applying unit applies a voltage different from the high frequency voltage applied between the upper electrode and the lower electrode between the lower electrode and the auxiliary electrode,
The upper electrode has a plurality of rectangular first electrode plates,
The lower electrode has a plurality of rectangular second electrode plates,
Each of the first electrode plate and the second electrode plate has a long side and a short side,
A high-frequency heating device in which the first electrode plate and the second electrode plate are arranged such that the long sides of the first electrode plate and the long sides of the second electrode plate intersect each other. An upper electrode,
A lower electrode disposed below the upper electrode,
A high-frequency heating device comprising a voltage applying unit that applies a high-frequency voltage between the upper electrode and the lower electrode,
An auxiliary electrode is provided around the upper electrode,
The voltage applying unit applies a voltage different from the high frequency voltage applied between the upper electrode and the lower electrode between the lower electrode and the auxiliary electrode,
Further comprising a second auxiliary electrode between the upper electrode and the lower electrode,
The second auxiliary electrode has an opening in the central portion and is arranged at substantially the same position as the upper surface of the object to be heated,
A high frequency heating device, wherein a voltage different from a high frequency voltage applied between the upper electrode and the lower electrode is applied between the lower electrode and the second auxiliary electrode. Further comprising a heating chamber accommodating the upper electrode and the lower electrode,
The high frequency heating device according to claim 1, wherein the auxiliary electrode is connected to the same potential as the heating chamber. The voltage applied between the lower electrode and the auxiliary electrode has the same frequency as the high frequency voltage applied between the upper electrode and the lower electrode, but has a phase opposite to the high frequency voltage. High frequency heating device. A door for opening and closing a heating chamber that houses the upper electrode and the lower electrode,
Further comprising a lifting mechanism for moving the upper electrode in the vertical direction,
The high-frequency heating device according to claim 1, wherein the elevating mechanism raises the upper electrode in conjunction with an opening operation of the door. An upper electrode,
A lower electrode disposed below the upper electrode,
A high-frequency heating device comprising a voltage applying unit that applies a high-frequency voltage between the upper electrode and the lower electrode,
The upper electrode has a plurality of rectangular first electrode plates,
The lower electrode has a plurality of rectangular second electrode plates,
Each of the first electrode plate and the second electrode plate has a long side and a short side,
A high-frequency heating device in which the first electrode plate and the second electrode plate are arranged such that the long sides of the first electrode plate and the long sides of the second electrode plate intersect each other.

Images