JP2007234535A - High frequency induction heating device, high frequency induction heating method, and subsidiary material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency induction heating device capable of evenly heating a material to be heated. <P>SOLUTION: The material 13 to be heated is pinched between a pair of a lower part electrode 11 and an upper part electrode 12 which face with each other. A high frequency voltage is applied between the lower part electrode 11 and the upper part electrode 12, and the material 13 to be heated is heated by high frequency induction. A lower part subsidiary material 14 and an upper part subsidiary material 15 formed of vulcanized rubber for keeping the material 13 to be heated warm are arranged respectively between the lower part electrode 11 and the material 13 to be heated, and the upper part electrode 12 and the material 13 to be heated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-frequency dielectric heating apparatus and a high-frequency dielectric heating method for heating while heating a material to be heated using auxiliary materials.

  Conventionally, as a method of heating various materials to be heated such as rubber, resin, and wood, a high-frequency dielectric heating method using high-frequency dielectric is known, and is described in Patent Document 1 as an example of this heating method. A method is disclosed. In Patent Document 1, an object to be heated is sandwiched between a pair of electrodes that are flat and made of metal, a high-frequency voltage is applied between both electrodes, and the object to be heated is heated.

In this method, the material to be heated is in contact with an electrode made of a metal having a relatively high thermal conductivity, and the contact portion absorbs heat by the electrode. Therefore, in the high-frequency dielectric heating method described in Patent Document 1, the heat absorption is performed. In order to prevent this, heating means for heating the electrode itself is provided. For example, steam or a heat transfer heater is used as the heating means.
Japanese Patent Laid-Open No. 9-289078

  However, if a heating means is provided separately from the high-frequency dielectric heating as in Patent Document 1, the configuration of the apparatus becomes complicated, and if a heat transfer heater is used as the heating means, it takes a long time to raise the temperature of the electrode. . Further, when steam is used as a heating means, steam leakage may occur. In this case, when steam enters between the electrodes, a rapid temperature rise occurs in the heated material, and an explosive burst occurs in the heated material. There is a case.

  Accordingly, the present invention has been made in view of the above problems, and a high-frequency dielectric heating apparatus capable of uniformly heating a material to be heated without providing any heating means other than high-frequency dielectric heating. The purpose is to provide.

  The high-frequency dielectric heating device according to the present invention sandwiches a material to be heated between a pair of electrodes facing each other, applies a high-frequency voltage between both electrodes, and heats the material to be heated by high-frequency dielectric. The apparatus is characterized in that an auxiliary material including a vulcanized rubber body for keeping the heated material is disposed between at least one of the electrodes and the heated material.

  The auxiliary material should be electrically insulated between the electrode and the material to be heated. This prevents a spark from being generated between the electrodes when a high frequency voltage is applied. The vulcanized rubber body is preferably non-conductive. For example, the vulcanized rubber body is not blended with carbon black, or is blended with 5 parts by weight or less of carbon black with respect to 100 parts by weight of the rubber component. The

  It is preferable that a metal-containing pigment is added to the vulcanized rubber body. This disperses the energizable metal (copper-containing pigment) in the secondary material, which is an insulator, so that the metal is energized and the secondary material is heated relatively quickly due to the dielectric of the surrounding insulator. It is presumed that the warming effect of auxiliary materials will increase.

  The auxiliary material may electrically insulate between the electrode and the material to be heated by sequentially arranging the non-conductor, the vulcanized rubber body, and the non-conductor from the electrode toward the material to be heated. .

  In the heating method of the heated material according to the present invention, the heated material is sandwiched between a pair of electrodes facing each other, a high frequency voltage is applied between both electrodes, and the heated material is heated by high frequency dielectric. The method is characterized in that a secondary material including a vulcanized rubber body for keeping the heated material is disposed between at least one of the electrodes and the heated material. The electrode on the side where the auxiliary material is provided does not need to be heated by a heating means other than high-frequency dielectric heating.

  The secondary material according to the present invention is used in a high-frequency dielectric heating apparatus that sandwiches a material to be heated between a pair of electrodes facing each other, applies a high-frequency voltage between both electrodes, and heats the material to be heated by high-frequency dielectric. It is an auxiliary material, and is disposed between at least one of the electrodes and the material to be heated, and includes a vulcanized rubber body for keeping the material to be heated.

  In the present invention, by arranging the secondary material between the electrode and the material to be heated, when the material to be heated is heated by high frequency dielectric, the secondary material itself is heated in the same manner, and the material to be heated is kept warm by the secondary material. Therefore, the heated material can be heated evenly without heating the heated material with another heat source other than the high frequency dielectric heating.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a high-frequency dielectric heating device according to the first embodiment. As shown in FIG. 1, the high frequency dielectric heating device 10 is made of metal and includes a lower electrode 11 and an upper electrode 12 which are spaced apart and face each other, and the surfaces of the lower electrode 11 and the upper electrode 12 facing each other are planar. The plate-like lower secondary material 14 and the upper secondary material 15 are attached to these surfaces, respectively.

  A material to be heated 13 is placed on the upper surface of the lower auxiliary material 14 provided on the lower electrode 11. The material to be heated 13 has, for example, a quadrangular prism, a columnar shape, and the like, and is provided with a heat insulating material 17 having a cylindrical shape or a rectangular tube shape so as to surround the outer periphery thereof, and the heat insulating material 17 is also an upper surface of the lower auxiliary material 14. It is mounted on.

  A cylinder 16 is attached to the upper electrode 12, and the upper electrode 12 is driven up and down by the cylinder 16. A power supply (not shown) for applying a high frequency voltage is connected to the lower electrode 11 and the upper electrode 12.

  The material to be heated 13 may be any material that can be heated by high-frequency dielectrics, and may be any material that includes unvulcanized rubber, various resins, elastomers, natural polymer materials, and the like. Of course, a composite material such as rubber and cloth or rubber and synthetic resin may be used.

  In this embodiment, the lower auxiliary material 14 and the upper auxiliary material 15 are used to keep the heated material 13 warm when the heated material 13 is heated. In this embodiment, each of the vulcanized rubber layers is used. Consist only of. As rubber components of the vulcanized rubber layer, natural rubber, styrene-butadiene rubber, chloroprene rubber, alkylated chlorosulfonated polyethylene, ethylene-propylene-diene terpolymer blend (EPDM), ethylene-propylene rubber ( EPR), nitrile rubber, hydrogenated nitrile rubber or the like, or a mixture thereof is used. However, it is preferable to use a rubber component having excellent heat resistance such as EPDM. This is because when the vulcanized rubber layer is excellent in heat resistance, the auxiliary material can be used repeatedly. Also, it is better not to use a rubber component having a low dielectric loss coefficient such as silicon rubber as the rubber component of this embodiment.

  The vulcanized rubber layer preferably has a dielectric loss coefficient equal to or higher than that of the material to be heated 13. When the dielectric loss coefficient is set in this way, the auxiliary materials 14 and 15 are also heated together with the heated material 13, or the auxiliary materials 14 and 15 are heated preferentially over the heated material 13, and the auxiliary materials 14 and 15 This is because the effect of keeping the heated material 13 warm is enhanced. The dielectric loss coefficient is a value defined by the product (εγ × tan δ) of the relative dielectric constant (εγ) and the dielectric loss angle (tan δ).

  The vulcanized rubber layer is obtained by blending various additives such as a vulcanizing agent and a reinforcing agent into the unvulcanized rubber made of the rubber component and vulcanizing and molding the vulcanized rubber layer. As the vulcanizing agent, a sulfur-based or peroxide-based vulcanizing agent can be used, but it is better to use a peroxide vulcanizing agent. This is because when the peroxide is used, the heat resistance of the auxiliary material is improved as compared with the case where the sulfur-based vulcanizing agent is used, and the auxiliary material can be used repeatedly. As an additive, it is preferable that a metal-containing pigment such as a copper-containing pigment is added to the vulcanized rubber layer. Because the metal (copper-containing pigment) that can be energized is dispersed in the secondary material that is an insulator, the metal is energized and the secondary material is heated relatively quickly due to the dielectric of the surrounding insulator. It is.

The vulcanized rubber layer is non-conductive, and its volume resistivity value is, for example, 1 × 10 ⁹ Ω · cm or more. Therefore, it is preferable that carbon black which is a conductive substance is not used as the main reinforcing agent used in the vulcanized rubber layer. That is, the main reinforcing agent used in the vulcanized rubber layer is preferably a non-conductive substance, for example, silica. For example, 5 to 100 parts by weight of silica is blended with respect to 100 parts by weight of the rubber component. Carbon black may be blended as the reinforcing agent, but the blending amount of carbon black is less than the blending amount of silica, for example, blending at a ratio of 5 parts by weight or less with respect to 100 parts by weight of the rubber component. Of course, the vulcanized rubber layer may not contain carbon black.

  As shown in FIG. 2, the upper electrode 12 is moved downward by the cylinder 16, and the heated material 13 is moved by the lower electrode 11 and the upper electrode 12 through the lower auxiliary material 14 and the upper auxiliary material 15, respectively. It is pinched. Along with this clamping pressure, a high frequency voltage is applied between the lower electrode 11 and the upper electrode 12. Here, the high frequency voltage is a high voltage (for example, 10,000 V), but the lower auxiliary material 14 and the upper auxiliary material 15 are non-conductive, and between the electrodes 11 and 12 and the material to be heated 13, Since it is electrically insulated, even if a high voltage is applied between both electrodes, no spark or the like occurs between the two electrodes.

  The heated material 13 is heated together with the lower auxiliary material 14 and the upper auxiliary material 15 by applying a high frequency voltage. Here, both electrodes 11 and 12 are made of metal and have a relatively high thermal conductivity, while the auxiliary materials 14 and 15 are made of a vulcanized rubber layer and have a relatively very low thermal conductivity. Therefore, the auxiliary materials 14 and 15 heated by the high frequency dielectric are absorbed by both the electrodes 11 and 12, but the heated material 13 is absorbed by both the electrodes 11 and 12 due to the heat insulating effect of the auxiliary materials 14 and 15. rare. Moreover, since the outer peripheral surface of the heated material 13 is surrounded by the heat insulating material 17 as described above, the heated material 13 does not radiate heat from the outer peripheral surface. Thereby, all the parts of the to-be-heated material 13 are heated uniformly.

  Further, since the lower auxiliary material 14 and the upper auxiliary material 15 are made of vulcanized rubber, they have high elasticity (low elastic modulus), and can sufficiently adhere to the heated material 13 when being clamped by both electrodes 11 and 12. . Therefore, the heated material 13 is appropriately heated by both voltages 11 and 12, and is efficiently heated by the high frequency dielectric.

  The heat insulating material 17 may be a material that compresses and deforms in the same manner as the material to be heated 13 due to the sandwiching pressure between both the electrodes 11 and 12, or is previously covered so that it is not sandwiched by the electrodes 11 and 12. The compression amount of the heating material 13 is taken into consideration, and the height may be set smaller than that of the heated material 13.

  In addition, as shown in FIG. 3, the to-be-heated material 13 may be the unvulcanized rubber etc. with which the inside of the cylindrical shaping | molding die 21 which consists of synthetic resins like an epoxy resin was filled. When the molding die 21 is used, the heated material 13 is provided slightly higher than the molding die 21 as shown in FIG. 3, so that when the heated material 13 is narrowed by both electrodes 11, 12, the molded material 21 is molded. The mold 21 is not energized with pressure from the electrodes.

  FIG. 4 shows the configuration of the lower secondary material 14 in the second embodiment of the present invention. In the second embodiment, the configurations other than the auxiliary materials 14 and 15 are the same as those in the first embodiment, and thus the description thereof is omitted. Moreover, since the structure of the upper submaterial 15 in 2nd Embodiment has the structure similar to the structure of the lower submaterial 14 of 2nd Embodiment, the description is also abbreviate | omitted.

  In the first embodiment, the lower secondary material 14 is composed of only a vulcanized rubber layer. However, in the second embodiment, the lower secondary material 14 is composed of first and second non-conductive materials. It consists of conductive sheets 31 and 32 and a vulcanized rubber layer 33 sandwiched between the non-conductive sheets 31 and 32. With such a configuration, the lower auxiliary material 14 can insulate the lower electrode 11 and the heated material 13 from each other. Therefore, even in the second embodiment, even if a high frequency voltage is applied between both electrodes, no spark occurs between the electrodes.

The first and second nonconductive sheets 31 and 32 are made of a nonconductive resin such as a fluororesin, for example, a polytetrafluoroethylene sheet. On the other hand, the vulcanized rubber layer 33 in the second embodiment may have a configuration similar to that of the vulcanized rubber layer in the first embodiment and may be non-conductive, but is preferably conductive. . When the vulcanized rubber layer 33 is conductive, the volume resistivity value is 1 × 10 ³ Ω · cm to 1 × 10 ⁷ Ω · cm. Therefore, the rubber component of the vulcanized rubber layer 33 is the same as that of the first embodiment, but as a main reinforcing agent blended in the rubber component, it is better to blend carbon black. 20-60 parts by weight is blended with 100 parts by weight of the rubber component.

  The auxiliary material 14 includes a vulcanized rubber layer 33 having a relatively low elastic modulus and non-conductive sheets 31 and 32 having a relatively high elastic modulus. The non-conductive sheets 31 and 32 are vulcanized rubber layers 33. Therefore, even in the second embodiment, when the heated material 13 is sandwiched between both electrodes, the auxiliary materials 14 and 15 can be in close contact with the heated material 13.

  As described above, in the first and second embodiments, when the material to be heated is heated by the high frequency dielectric by arranging the auxiliary material for keeping the material to be heated between the electrode and the material to be heated. Since the material to be heated is kept warm by the auxiliary material, the material to be heated can be evenly heated without heating the material to be heated by another heat source other than the high frequency dielectric heating. In addition, since the auxiliary material is formed of a vulcanized rubber body having high elasticity, it is possible to appropriately pressurize the material to be heated by both electrodes.

  In the first and second embodiments, a release agent is provided between the auxiliary materials 14 and 15 and the heated material 13 in order to facilitate the release of the heated material 13 from the auxiliary materials 14 and 15. May be applied.

In the first and second embodiments, the auxiliary material is provided between both the electrodes 11 and 12 and the material to be heated 13, but either one of the electrodes 11 and 12 and the material to be heated are provided. The auxiliary material may be provided only between 13. In this case, the electrode on the side where the auxiliary material is provided does not need to be heated by a heating means other than the high frequency dielectric heating. Further, the electrode on the side where the auxiliary material is not provided is preferably heated by a heating means different from the high frequency dielectric heating. In this specification, a conductive substance means a substance having a volume resistivity of less than 1 × 10 ⁸ Ω · cm, and a non-conductive substance means a volume resistivity of 1 × 10. ⁸ Ω · cm or more.

  EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not necessarily limited to a following example.

  In this example, the following experimental examples 1 to 3 were performed. In Experimental Examples 1 to 3, as shown in FIG. 3, a cylindrical mold made of an epoxy resin was prepared, and unvulcanized rubber filled in the mold was used as a material to be heated. The mold had an outer diameter of 10 cm, an inner diameter of 9 cm, and a height of 3 cm. The material to be heated was 3.3 cm in height, and a part of the material protruded 0.3 cm from the upper part of the mold. And, as shown in FIG. 3, the lower secondary material, the upper electrode with the upper secondary material attached to the surfaces facing each other, the unvulcanized rubber is sandwiched at 1.2 MPa by the lower electrode, and the upper electrode and the lower electrode High frequency dielectric heating was performed by applying a high frequency voltage, and unvulcanized rubber was vulcanized. In each of Experimental Examples 1 to 3, the thicknesses of the upper subsidiary material and the lower subsidiary material are set to 3 mm, 5 mm, and 8 mm, respectively, and are performed even when there is no upper subsidiary material and lower subsidiary material. It was. The high-frequency oscillator used in this test was 7 kW, the oscillator current value was 0.4 A, and no other heat source was used.

[Composition of secondary materials]
The upper submaterial and the lower submaterial of Experimental Examples 1 to 3 are each composed of a vulcanized rubber layer, and the composition thereof is shown in Table 1. As can be seen from Table 1, Experimental Example 1 is an example using silica as the main reinforcing agent. The blending of the auxiliary materials in Experimental Example 2 is the same as that in Experimental Example 1 except that the copper-containing pigment is added. Experimental Example 3 is an example using carbon black as the main reinforcing agent.

[Composition of heated material]
The compositions of the materials to be heated in Experimental Examples 1 to 3 are the same, and are shown in Table 2.

[Experimental result]
The experimental results of Experimental Example 1 and Experimental Example 2 are shown in Tables 3 and 4, respectively. In Experimental Examples 1 to 3, a high frequency voltage was applied for 5 minutes, and the temperature of the material to be heated was measured at the time when 1, 3 and 5 minutes passed. The temperature of the material to be heated was measured at an intermediate position in the height direction, an upper position, and a lower position in the axis of the material to be heated by an optical fiber thermometer inserted into the material to be heated. The upper position and the lower position in the height direction refer to positions that are 2 mm and 2 mm apart from the upper surface and the lower surface of the heated material before pressing, respectively. The intermediate position refers to an intermediate position between the upper position and the lower position. Further, in this example, a hole was formed in the mold, and a thermometer was inserted into the material to be heated from the hole.

  As shown in Table 3, in Experimental Example 1, the temperature difference between the intermediate position and the upper and lower positions is smaller when the lower auxiliary material and the upper auxiliary material are provided than when the auxiliary material is not provided. Thus, it can be understood that the material to be heated is heated uniformly. In addition, it can be understood that the larger the thickness of the auxiliary material, the more uniformly heated. That is, it can be understood that the greater the thickness, the less the heat energy propagates from the heated material to the electrode, and the heated material is more uniformly heated. Also, compared to the case where no auxiliary material is provided, when the auxiliary material is provided, the temperature of the heated material is generally higher even if the heating time is the same. It can be understood that the material to be heated is heated.

  As shown in Tables 3 and 4, in Experimental Example 2, the rate of temperature increase was faster than in Experimental Example 1, and heating was performed more efficiently than in Experimental Example 1. This is because, in Experimental Example 2, the metal (copper-containing pigment) that can be energized is dispersed in the secondary material that is an insulator, so that the metal is energized, and the secondary material is caused by the dielectric of the surrounding insulator. It is presumed that the heat of the auxiliary materials has been increased due to the rapid heating of the materials. In particular, when the thickness is 8 mm, the temperature at the upper position and the lower position is higher than the intermediate position, so that it is assumed that the thermal energy is transmitted from the auxiliary material to the heated material. That is, in Experimental Example 2, it is presumed that the dielectric loss coefficient of the auxiliary material is higher than that of the heated material, and the temperature rising rate of the auxiliary material is faster than the temperature rising rate of the heated material.

  As described above, since the temperature increase rate of the heated material can be changed by changing the rubber composition of the auxiliary material, in the present invention, by appropriately selecting the auxiliary material, the heated material can be efficiently heated. The temperature distribution can be made uniform.

  In Experimental Example 3, when the thickness of the auxiliary material was 3, 5, and 8 mm, sparks were generated between both electrodes, and the material to be heated could not be stably heated. That is, it can be understood that when the secondary material is composed of a single rubber layer, if the rubber layer is conductive, sparks are generated by a high-frequency high voltage, and therefore the secondary material should be non-conductive.

It is sectional drawing which shows typically the high frequency dielectric heating apparatus which concerns on 1st Embodiment. It is sectional drawing which shows typically the high frequency dielectric heating apparatus which concerns on 1st Embodiment, Comprising: A mode when a to-be-heated material is pressurized with both electrodes is shown. It is sectional drawing which shows typically a high frequency dielectric heating apparatus in case a to-be-heated material is the unvulcanized rubber with which the inside of the shaping | molding die was filled. It is sectional drawing of the lower submaterial in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 High frequency dielectric heating apparatus 11 Lower electrode 12 Upper electrode 13 Material to be heated 14 Lower auxiliary material 15 Upper auxiliary material 21 Mold

Claims (9)

  In a high frequency dielectric heating apparatus for sandwiching a material to be heated between a pair of electrodes facing each other, applying a high frequency voltage between the two electrodes, and heating the material to be heated by high frequency dielectric, at least one of them A high-frequency dielectric heating apparatus comprising: a sub-material including a vulcanized rubber body for keeping the heated material between the electrode and the heated material.   The high frequency dielectric heating apparatus according to claim 1, wherein the auxiliary material electrically insulates between the electrode and the material to be heated.   The high-frequency dielectric heating device according to claim 1, wherein the vulcanized rubber body is non-conductive.   4. The high frequency dielectric heating device according to claim 3, wherein the vulcanized rubber body is not compounded with carbon black or is blended with 5 parts by weight or less of carbon black with respect to 100 parts by weight of the rubber component. .   The high-frequency dielectric heating device according to claim 1, wherein a metal-containing pigment is added to the vulcanized rubber body.   The auxiliary material is formed by sequentially arranging a non-conductor, the vulcanized rubber body, and a non-conductor from the electrode toward the material to be heated, and electrically insulates between the electrode and the material to be heated. The high-frequency dielectric heating device according to claim 1, wherein   In a high frequency dielectric heating method in which a material to be heated is sandwiched between a pair of electrodes facing each other, a high frequency voltage is applied between the two electrodes, and the material to be heated is heated by high frequency dielectric, at least one of the electrodes A heating method for a material to be heated, characterized in that an auxiliary material including a vulcanized rubber body for keeping the material to be heated is disposed between the material to be heated and the material to be heated.   The heating method for a material to be heated according to claim 7, wherein the electrode on the side where the auxiliary material is provided is not heated by a heating means other than the high-frequency dielectric heating.   A secondary material used in a high-frequency dielectric heating apparatus that sandwiches a heated material between a pair of electrodes facing each other, applies a high-frequency voltage between the electrodes, and heats the heated material by high-frequency dielectric, An auxiliary material, comprising: a vulcanized rubber body disposed between at least one of the electrodes and the material to be heated and for keeping the material to be heated.

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