JPH0997674A - Grid electrode of high-frequency heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of discharge in a grid electrode by preventing steam generated in a heated body due to induction heating from being condensed into a dewdrop in the surface of the grid electrode. SOLUTION: A grid electrode 32 on a plus side is composed of a tubular body made of metal, and a plurality of air jetting holes 323 are perforated at predetermined intervals in the axial direction in the outer circumferential surface opposite to the surface of a heated body P. A connection part 322 provided at one end of the grid electrode 32 is connected to a compressed-air generating device through an insulating pipe, and compressed air supplied from the compressed-air generating device is jetted toward the surface of the heated body P from the air jetting holes 323. Steam jetted from the surface of the heated body P by high-frequency heating is dispersed by the compressed air jetted from the air jetting holes 323, thereby preventing dew condensation to the surface of the grid electrode 32 and the high moisturizing of air in the periphery of the grid electrode 32 to suppress the generation of discharge in the grid electrode 32.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to, for example, LVL (La
Mined Veneer Lumber) etc. for grid electrodes of high-frequency heating devices used for drying and laminating veneer laminated materials, and for building and adhering construction materials, etc., where a decorative board is adhered to the surface of the lumber, especially for discharge prevention structure of grid electrodes Is.

[0002]

2. Description of the Related Art Conventionally, a surface heating type high-frequency heating device is known as a device for efficiently drying the above-mentioned laminated veneer lumber and dry adhering a decorative board to the lumber surface.

This high-frequency heating device comprises a plurality of rod-shaped plus electrodes and minus electrodes arranged in proximity to the surface of the object to be heated and arranged alternately and in parallel with each other, and the above-mentioned grid electrodes. It consists of a high-frequency generator that supplies high-frequency power between the positive electrode and the negative electrode.The high-frequency electric field generated between the positive electrode and the negative electrode is permeated into the surface layer of the object to be heated and heated by the dielectric loss. It promotes surface drying and dry adhesion of the object to be heated.

[0004]

When wood or the like is dried or dry-bonded by dielectric heating, the moisture in the wood is rapidly heated to high-pressure steam, and this steam is pushed out from the surface of the wood to the outside of the grid electrode. The surroundings become extremely humid. For this reason, the dielectric strength of air, which is an insulating layer between the grid electrode and the wood surface, decreases, and the water droplets of the dew condensation of the water vapor adhere to the grid electrode surface, resulting in the discharge between the water droplet and the wood surface. .

The conventional high-frequency heating device is designed so that hot air is circulated in the device to suppress the increase in humidity due to the water vapor as much as possible and accelerate the drying by high-frequency heating. Since it is not possible to completely prevent water droplets from adhering to the electrode surface, discharge easily occurs at the grid electrode during dielectric heating, which leads to a decrease in efficiency such as drying due to high frequency heating, and scorching due to discharge on the wood surface. Occasionally, adhesion failure may occur.

Although it is possible to increase the effect of preventing water droplets from adhering to the grid electrode surface by increasing the amount of hot air supplied or by blowing air toward each grid electrode, this method requires a large hot air supply device. And it gets complicated.

The present invention has been made in view of the above problems, and effectively suppresses the occurrence of electric discharge with a simple structure, efficiently, and also for drying, bonding, etc. of the object to be heated without damaging the object to be heated. The present invention provides a grid electrode for a high-frequency heating device capable of performing the above.

[0008]

The present invention relates to a grid electrode for a high-frequency heating device which is arranged close to the surface of an object to be heated so as to form a high-frequency electric field on the surface layer of the object to be heated. At least the positive electrode is constituted by a tubular body provided with a gas jetting portion for jetting the externally supplied high pressure gas at least on the outer peripheral surface facing the surface of the object to be heated (Claim 1). .

The gas jetting portion may be formed of a plurality of holes discretely formed in the axial direction of the plus electrode tube (claim 2), and may be formed of one or two or more slits. (Claim 3). Further, the outer peripheral surface of the positive electrode may be covered with an insulating member (claim 4).

According to the above construction, in the high-frequency heat treatment, the high-pressure gas supplied into the tube of the grid electrode is jetted from the gas supply unit consisting of a plurality of holes or slits toward the surface of the object to be heated. Water vapor is generated from the surface of the object to be heated by dielectric heating, but this water vapor is blown off by the high-pressure gas, without condensation on the grid electrode surface,
Higher humidity of air, which is an insulating layer between the grid electrode and the surface of the object to be heated, is also reduced.

Therefore, the discharge phenomenon between the grid electrode and the surface of the object to be heated is suppressed by reducing the adhesion of water droplets on the surface of the grid electrode due to dew condensation and reducing the humidity of the air as the insulating layer.

Further, by covering the outer peripheral surface of the grid electrode with an insulating member, the surface potential of the grid electrode is lowered,
The discharge suppression effect is improved.

Further, according to the present invention, in order to form a high frequency electric field on the surface layer of the object to be heated, a pair or two of them are placed close to the surface of the object to be heated.
In a grid electrode of a high-frequency heating device arranged in pairs or more, at least a positive electrode of the grid electrode and an insulating sheet member provided between the surface of the object to be heated are provided (Claim 5).

The plurality of grid electrodes are rod-shaped electrodes arranged on one surface of the support board at a predetermined interval, and the insulating sheet member faces the surface of the plurality of grid electrodes to be heated. It is advisable to mount it on the support plate so as to cover the outer peripheral surface (claim 6).

The plurality of grid electrodes are rod-shaped electrodes arranged on one surface of the supporting board at a predetermined interval, and the insulating sheet member is arranged on one side of the supporting board in the arrangement direction of the grid electrodes. A feeding roller provided at an end of the grid electrode is fed so as to cover an outer peripheral surface of the plurality of grid electrodes facing the surface of the object to be heated, and is provided at the other end of the support plate in the arrangement direction of the grid electrodes. It is preferable to use a roll film wound by a winding roller (claim 7).

Further, the plurality of grid electrodes are rod-shaped electrodes arranged on one surface of the support board at a predetermined interval, and the insulating sheet member faces the surface of the plurality of grid electrodes to be heated. It is preferable that the belt-shaped film sheet is provided around the support plate and the grid electrode so as to cover the outer peripheral surface thereof.

According to the above construction, the water vapor spouted from the surface of the heated body is shielded by the insulating sheet member interposed between the grid electrode and the surface of the heated body, and the dew condensation does not occur on the surface of the grid electrode. Further, the insulating sheet member reduces the surface potential of the grid electrode.

Therefore, the phenomenon of discharge between the grid electrode and the surface of the object to be heated is suppressed by preventing water droplets from adhering to the surface of the grid electrode due to dew condensation and lowering the surface potential of the grid electrode.

Further, the insulating sheet member interposed between the grid electrode and the surface of the object to be heated is exchanged by winding the roll film with a winding roller or by winding a belt-shaped film sheet.

Further, according to the present invention, the plurality of grid electrodes are bar-shaped electrodes arranged on one surface of the supporting plate at a predetermined interval, and the insulating sheet member is at least the outer periphery of the bar-shaped electrodes on the plus side. It is composed of an insulating film for covering the surface (claim 9).

According to the above structure, the surface potential of the grid electrode is lowered by the insulating film coated on the outer peripheral surface of the grid electrode, and the discharge phenomenon between the surface of the grid electrode and the surface of the heated object is suppressed.

Further, according to the present invention, the plus-side rod-shaped electrode is constituted by a tubular body through which a fluid can flow (claim 10).

According to the above structure, the grid electrode is heated by circulating a high temperature fluid in the tube of the grid electrode. Water vapor is generated from the surface of the object to be heated by dielectric heating, but since the grid electrode is heated, condensation of the water vapor on the grid electrode surface is prevented, which contributes to a decrease in the surface potential of the grid electrode due to the insulating film. Therefore, the discharge phenomenon between the surface of the grid electrode and the surface of the object to be heated is suppressed.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 7 is a side view showing a schematic structure of a high-frequency heating apparatus having a grid electrode according to the present invention, and FIG. 8 is a front view showing a schematic structure of the same high-frequency heating apparatus.

The high-frequency heating device 1 shown in the figure is made of lumber P1.
The building material P (hereinafter referred to as a heated object P), which is obtained by bonding a decorative plate P2 (thin plate) to the surface of the same with a thermosetting adhesive P3, is dried and bonded.

The high-frequency heating device 1 is composed of a carrying section 2 for carrying the heated object P while pressurizing it, and a high-frequency generating section 3 for irradiating the surface layer of the heated object P with a high-frequency electric field. The transport unit 3 is composed of a plurality of paired transport rollers 21, 21 'and a roller driving unit (not shown), and each transport roller 21, 21'.
Are arranged at a predetermined interval from the upstream side to the downstream side. The upper conveying roller 21 can be moved up and down by a drive mechanism (not shown), and the distance between the upper conveying roller 21 'and the lower conveying roller 21' can be adjusted according to the thickness of the object P to be heated.

The object to be heated P is held by a lower conveying roller 21 'and an upper roller 21 at a predetermined pressure, and is conveyed downstream by a rotational drive of both conveying rollers 21, 21' at a predetermined speed. .

The high frequency generator 3 generates a predetermined high frequency power, a high frequency generator 31, grid electrodes 32 and 33 to which the high frequency power is supplied, and the grid electrodes 32 and 3.
3, a compressed air generator 35 that supplies high temperature and high pressure compressed air to the positive side grid electrode 32,
It is composed of a blower duct 36 for guiding the high-pressure air to the plus side grid electrode 32 and an insulating pipe 37 made of PTFE (polytetrafluoroethylene) for connecting the blower duct 36 and each grid electrode 32.

The upper plate 34 can be moved up and down by a drive mechanism (not shown), and in the heating process of the object P to be heated, the lower surfaces of the grid electrodes 32 and 33 have a predetermined height from the surface of the object P to be heated. For example, it is arranged to be lowered at a position having a height of 3 to 5 mm.

The grid electrodes 32 and 33 are rod-shaped electrodes having a predetermined length dimension, and at least the plus-side grid electrode 32 is a hollow tubular electrode.

FIG. 1 shows the first side of the positive side grid electrode 32.
2 is a vertical sectional view of the embodiment of FIG. 2, and FIG. 2 is a horizontal sectional view of the grid electrode 32.

The grid electrode 32 is a tubular electrode having an elliptical cross section, and is made of a metal such as aluminum, copper or iron. One end of the grid electrode 32 is closed, and the other end is a compressed air supply hole 321 for supplying high-pressure compressed air into the pipe.
Is provided. The compressed air supply hole 321 is provided with a connection portion 322 having a male thread, and an insulating pipe 37 branched and connected to the blower duct 36 is screwed on.

A plurality of circular air ejection holes 323 for ejecting the compressed air supplied into the tube are formed on the outer peripheral surface (hereinafter referred to as the lower surface) of the grid electrode 32, which faces the surface of the object P to be heated. It is set up.

The air ejection holes 323 are, as shown in FIG.
The grid electrodes 32 are provided on the lower surface in a matrix. For example, in the case of the grid electrode 32 having a diameter of about 15 mm, the air ejection holes 323 having a diameter of about 1.5 mm have 10 to 15
It is arranged in mm pitch.

In the figure, three lines of ejection holes arranged at predetermined intervals in the axial direction are arranged on the lower surface of the grid electrode 32 at predetermined intervals in the circumferential direction. Only one line of the ejection holes may be provided on the lower surface of 32 which is the closest to the surface of the body P to be heated. In addition, as shown in FIG. 2, the air ejection holes 323 eject water vapor Q generated in the object P to be heated by dielectric heating from the air ejection holes 323 to disperse the compressed air, so that the grid electrode 32 of the water vapor Q is ejected. It is preferable to provide it on at least the lower surface of the grid electrode 32 in order to prevent the air ejection holes 32 from forming on the entire outer peripheral surface of the grid electrode 32.
3 may be provided.

Further, as shown in FIGS. 4 and 5, the air ejection holes may be one or two or more slits 323 extending in the axial direction provided on the lower surface of the grid electrode 32. As shown in, a plurality of slits 323 provided on the lower surface of the grid electrode 32 and extending in the direction perpendicular to the axial direction may be used.

Furthermore, although one end of the tubular electrode is closed in the present embodiment, one end may be opened so that the jetting force of the compressed air from the air jetting hole 323 can be adjusted. Further, since the compressed air supply hole 322 and the ejection force adjusting mechanism are for ejecting the compressed air from the air ejection hole 323 at a predetermined pressure, the arrangement positions thereof are limited to both ends of the tubular electrode. It may be the outer peripheral surface of the tubular electrode instead of the one.

Returning to FIG. 1, a terminal plate 324 for applying a high frequency to the grid electrode 32 is provided on the outer peripheral surface (hereinafter referred to as the upper surface) opposite to the lower surface of the grid electrode 32 along the axial direction. Has been done. The grid electrode 32 is formed by fixing the terminal plate 324 to a plus terminal 341 provided on the lower surface of the upper board 34 via a conductive supporting member 38 made of the same member as the grid electrode 32. It is attached to the bottom surface.

The minus-side grid electrode 33 is a solid rod-shaped electrode having the same appearance as the plus-side grid electrode 32, and like the plus-side grid electrode 32, a terminal provided on the upper surface of the electrode. A negative terminal 342 provided on the lower surface of the upper board 34 with a plate interposed via a support member 39.
It is fixed to and attached to the lower surface of the upper plate 34.

In this embodiment, the grid electrode 3
Although the cross-sectional shapes of 2 and 33 are elliptical, they may be circular or rectangular. Also, the negative side grid electrode 3
3 may have the same structure as the positive side grid electrode 32, and compressed air may be jetted from the lower surface of the electrode.

The upper plate 34 is made of a metal plate such as aluminum or iron and is grounded to the ground of the high frequency heating device 1.
The minus terminal 342 is provided directly connected to the upper board 34, and the positive terminal 341 is provided on the upper board 34 via an insulating member. The upper board 34 may be made of an insulator made of synthetic resin.

The high frequency generator 31 has a power supply circuit, a high frequency oscillating circuit, etc. inside, and 13.56 MHz, 27.12.
It generates high frequencies of licensed frequencies such as MHz and 40.68 MHz. The high frequency generator 31 has an unbalanced output terminal pair, the signal side terminal of this unbalanced output terminal pair is connected to the plus terminal 341, and the earth side terminal is connected to the minus terminal 342. High frequency generator 3
The high frequency generated in 1 is output from the unbalanced output terminal pair and is supplied to the grid electrodes 32 and 33 via the plus terminal 341, the minus terminal 342, and the supporting members 38 and 39.

In this embodiment, high frequency power is supplied to the grid electrodes 32 and 33 by the unbalanced power supply method, but high frequency power may be supplied by the balanced power supply method.

The compressed air generator 35 has a heating part and a compression part inside, and heats the air to a predetermined high temperature.
It is output after being compressed to a predetermined high pressure. The hot compressed air generated by the compressed air generator 35 is blown by the blower duct 3
6 to the grid electrodes 32 on the plus side through the insulating pipes 37.

Since the compressed air blows off the steam ejected from the surface of the object to be heated P, it may be a compressed gas other than air. Further, in the present embodiment, high temperature compressed air is supplied, but normal temperature compressed air may be supplied.

Although not shown, it is preferable that hot air be circulated in the apparatus to suppress an increase in internal humidity and promote drying.

In the above structure, the dry adhesion of the object to be heated P is performed as follows. That is, the high frequency generator 3
High frequency voltage generated in 1 is the positive side grid electrode 3
2 is applied between the negative electrode and the negative grid electrode 33, and a high frequency electric field is formed between the two electrodes. The high frequency electric field is generated in the horizontal direction because the plurality of grid electrodes 32 and 33 are alternately arranged in the horizontal plane.

Further, the high temperature and high pressure compressed air generated by the compressed air generator 35 is supplied to the blower duct 36 and the insulating pipe 3.
It is supplied to the inside of the tube of the grid electrode 32 on the plus side via 7 and is jetted downward from the air jet holes 323 on the lower surface of the grid electrode 32.

The object to be heated P has the grid electrode 3 so that the high frequency electric field can penetrate into the surface layer of the object to be heated P.
A pair of conveying rollers 2 with their surfaces close to the lower parts of 2, 33
1, 21 'conveys horizontally. When the high-frequency electric field penetrates into the surface layer of the object to be heated P, the material P1, the decorative plate P2, and the adhesive P3 in the surface layer are heated by the high-frequency dielectric loss, and the thermoplastic adhesive P3 is heated and solidified, and the material P1. The moisture in the decorative plate P2 and the adhesive P3 becomes water vapor and flows out from the surface of the heated object P to the outside to promote dry adhesion.

In the dry bonding step, the object P to be heated is
On the surface of the positive electrode, the heating temperature is higher in the vicinity of the positive side grid electrode 32 than in the vicinity of the negative side grid electrode 33, and as shown in FIG.
A large amount of water vapor Q is ejected at a position near 2. However, since the grid electrode 32 is heated by the high temperature compressed air and the water vapor Q is blown away by the compressed air ejected from the air ejection holes 323 provided on the lower surface of the grid electrode 32, the water vapor Q Grid electrode 3
Water droplets due to dew condensation on the surface of No. 2 are prevented. Furthermore,
The increase in humidity of air, which is an insulating layer between the grid electrode 32 and the surface of the body P to be heated, is reduced, and the decrease in withstand voltage is also suppressed.

When water droplets adhere to the surface of the grid electrode 32, the electric field concentrates on the water droplets, and discharge is likely to occur from the water droplets toward the surface of the object P to be heated. Since the dew condensation on the surface of the grid electrode 32 is prevented and the humidity of the air, which is an insulating layer, is reduced, the occurrence of the above-mentioned discharge phenomenon is suppressed, whereby the efficiency of high-frequency heating due to the above-mentioned discharge phenomenon is suppressed. The decrease can be reduced and damage such as scorching of the surface of the heated object P due to the above-mentioned discharge phenomenon can be prevented.

FIG. 9 shows a fourth grid electrode according to the present invention.
It is a perspective view of the electrode part of the high frequency heating apparatus which has embodiment of this. Further, FIG. 10 is a vertical sectional view of the same electrode portion, and FIG. 11 is a horizontal sectional view of the same electrode portion.

The electrode portion 40 shown in FIG. 9 is made of epoxy resin,
A plus side electrode 32 'and a minus side electrode 33' each having a rectangular cross section and having a rectangular cross section are provided in parallel with each other on the lower surface of an insulating upper plate 34 'made of a synthetic resin such as POM (polyoxymethylene) or PTFE. , And are buried alternately. The lower surface of the grid electrodes 32 ', 33' is the upper plate 3
It has the same height as the lower surface of 4 ', and a plurality of air ejection holes 323 are formed in the lower surface of the positive side grid electrode 32' at a predetermined pitch in the axial direction. A connecting portion 322 to which the insulating pipe 37 is connected is provided at one end of the grid electrode 32 '.

Although the negative grid electrode 33 'is hollow in FIG. 10, it may be solid.

FIG. 12 is a cross sectional view of a fifth embodiment of the grid electrode according to the present invention. In the first to fourth embodiments described above, a mechanism for ejecting compressed air is provided on the lower surface of the positive side grid electrodes 32, 32 ', and the water vapor ejected from the surface of the heated object P is blown away to form water droplets on the grid electrode 32. In order to prevent adhesion, in the fifth embodiment, in addition to the above-mentioned compressed air ejection mechanism, the outer peripheral surface of the grid electrode 32 is made of an insulating material such as PTFE, PE (polyethylene), PP (polypropylene), fluororesin, or the like. It is coated with a thin film of 325.

The thin film 325 may be formed by applying an insulating paste, or may be formed by adhering an insulating film or an insulating sheet.

The outer peripheral surface of the grid electrode 32 is covered with the insulating member 32.
When coated with 5, the insulating member 325 lowers the surface potential of the grid electrode 32 and relatively increases the dielectric strength, so that the effect of suppressing the discharge phenomenon can be enhanced.

FIG. 13 is a vertical sectional view of an electrode portion of a high frequency heating apparatus having a sixth embodiment of the grid electrode according to the present invention. In the grid electrode shown in FIG. 13, the lower surface of the grid electrode 32 'in FIG. 11 is covered with an insulating member 325. The same effect as that of the grid electrode 32 shown in FIG. 12 can be obtained.

FIG. 14 is a vertical sectional view of the grid electrode according to the seventh embodiment, and FIG. 15 is a horizontal sectional view of the grid electrode.

The grid electrode 32 "shown in FIG.
In which the air ejection hole 323 is removed, a fluid discharge hole 321 'and a male threaded connecting portion 322' are also provided at one end, and the outer peripheral surface of the electrode is covered with the insulating member 325. .

The connecting portions 322 and 322 'are connected to a fluid circulating device (not shown) through an insulating pipe 37 and a duct (not shown), and the grid electrode 32 "is provided with a high temperature fluid K in the electrode tube.
Is circulated and heated. That is,
The fluid K such as high temperature steam, air or oil supplied from this fluid circulation device is supplied into the pipe of the grid electrode 32 from the fluid supply hole 322 and returned to the fluid circulation device from the fluid discharge hole 322 '. The flow of the fluid K causes the grid electrode 32 ″ to be heated.

Grid electrode 32 ″ according to the seventh embodiment
Covers the outer peripheral surface of the grid electrode 32 ″ with an insulating member 325 to suppress the occurrence of the above-mentioned discharge phenomenon, and heats the grid electrode 32 ″ to prevent dew condensation of the water vapor Q ejected from the surface of the heated object P. This is to prevent it.

When this grid electrode 32 "is used,
The surface potential of the grid electrode 32 ″ is suppressed by the insulating member 325 ″, and as shown in FIG. 15, the water vapor Q ejected from the surface of the object to be heated P is heated by the grid electrode 32 ″ and condensed on the electrode surface. Since there is no such thing,
As in the sixth embodiment, it is possible to suppress the occurrence of a discharge phenomenon between the grid electrode 32 ″ and the heated body P.

By the way, in the seventh embodiment, the outer peripheral surface of the plus side grid electrode 32 ″ is covered with the insulating member 325 so that the insulating member 325 is interposed between the grid electrode 32 ″ and the heated body P. However, all grid electrodes 3
An insulative sheet member may be interposed between the surfaces 2 and 33 and the surface of the object to be heated P to suppress the surface potential of the positive grid electrode 32.

FIG. 16 is a perspective view of an electrode portion of a high frequency heating apparatus having an eighth embodiment of the grid electrode according to the present invention.

The electrode portion 40 'shown in the figure has a grid electrode 32 ", on the lower surface of the upper plate 34, with support members 38, 39 interposed therebetween.
33 ″ is projected downward, and this grid electrode 32 ″,
Band-shaped insulating sheet member 4 having substantially the same width as 33 ″
1 covers the lower surfaces of the grid electrodes 32 ″ and 33 ″, and both ends of the sheet member 41 are fixed to the upper surfaces of both ends of the upper plate 34. The grid electrodes 32 ″ and 33 ″ may be tubular electrodes through which fluid can flow, or solid rod-shaped electrodes.

In this embodiment, when the upper plate 34 is lowered to a predetermined position during dielectric heating, the grid electrodes 32 ",
The sheet member 4 is formed on the entire surface between the surface of 33 ″ and the surface of the heated object P.
1, the surface potential of the grid electrode 32 ″ is lowered, and the water vapor ejected from the surface of the object to be heated P is shielded by the sheet member 41 and condensed on the grid electrodes 32 ″, 33 ″. Therefore, it is possible to effectively suppress the occurrence of discharge.

FIG. 17 is a side view of an electrode portion of a high frequency heating apparatus having a ninth embodiment of the grid electrode according to the present invention.

In the electrode portion shown in FIG. 16, an endless belt-shaped sheet member 41 is provided around the electrode portion 40 'in place of the belt-shaped sheet member 41 in FIG. Driving rollers 343 and 344 for conveying the sheet member 41 are provided at both ends of the upper plate 34, and a plurality of guide rollers 345 are provided on the upper plate 34, and the sheet member 41 has the grid electrode 32 ″. , 3
The drive rollers 343, 3 so as to cover the lower surface of 3 ″.
It is wound around 44 and the guide roller 345.

In this embodiment, when the dielectric heat treatment is performed a predetermined number of times or more, the grid member 3 is rotated by rotating the sheet member 41 manually or by the power of a motor or the like.
The sheet member 41 provided between the 2 ″ and 33 ″ and the surface of the heated object P can be replaced.

FIG. 18 is a side view of an electrode part of a high frequency heating apparatus having a tenth embodiment of the grid electrode according to the present invention.

The electrode portion shown in FIG. 16 has a roll-shaped sheet member 41 instead of the strip-shaped sheet member 41 in FIG.
Is provided. A feed roller 346 for supplying the roll-shaped sheet member 41 and a take-up roller 347 for winding the roll-shaped sheet member 41 are provided at both ends of the upper plate 34, and the roll-shaped sheet member 41 includes the grid electrodes 32 ", 33". The feeding roller 346 and the take-up roller 34 cover the lower surface.
It is built between 7

In this embodiment, when the dielectric heating process is performed a predetermined number of times or more, the grid electrode 3 is wound by manually winding the sheet member 41 or by the power of a motor or the like.
The sheet member 41 provided between the 2 ″ and 33 ″ and the surface of the heated object P can be replaced.

The upper plate 34 'has grid electrodes 32',
Also for the electrode portion 40 formed by projecting 33 ',
As shown in FIG. 21, the sheet member 41 is manufactured by the same method.
Can be provided. FIG. 19 shows a configuration corresponding to FIG. 16, in which the belt-shaped sheet member 41 is fixed to both ends of the upper board 34 '. Further, FIG. 20 shows a configuration corresponding to FIG. 17, in which an endless belt-shaped sheet member 41 is provided so as to be able to wrap around the electrode portion 40. Further, FIG. 21 shows a configuration corresponding to FIG. 18, in which a roll-shaped sheet member 41 is provided so as to be wound around the electrode portion 40.

In the above embodiment, the building material P is dried and
Although the high-frequency heating device for adhering has been described, the present invention is not limited to such an application, and the grid electrode of the high-frequency heating device for dielectrically heating another object to be heated having a relatively high water content, such as grain. It can also be widely applied to.

[0076]

As described above, according to the present invention,
Since at least the positive electrode of the grid electrode is composed of a tubular body provided with a gas ejection portion for ejecting the externally supplied high-pressure gas to at least the outer peripheral surface facing the surface of the object to be heated, the high frequency heating Even when water vapor is generated from the heated body, the high-pressure gas supplied into the electrode tube is ejected from the gas ejection portion to blow off the water vapor, whereby water droplets are attached due to dew condensation on the grid electrode surface and the grid electrode and the heated body. It is possible to reliably prevent the humidity of the air, which is an insulating layer between the surfaces, from increasing. This suppresses the discharge phenomenon that occurs between the grid electrode and the surface of the heated object,
It is possible to reliably prevent deterioration of the treatment efficiency of high-frequency heating and damage such as scorching of the surface of the object to be heated due to this discharge phenomenon.

Further, since the outer peripheral surface of the grid electrode is covered with the insulating member, the surface potential of the grid electrode is lowered,
The effect of suppressing the discharge phenomenon is further improved.

Further, according to the present invention, at least one of the grid electrodes of the high-frequency heating device is arranged at least in pairs in order to form a high-frequency electric field on the surface layer of the object to be heated and is arranged close to the surface of the object to be heated. Since the insulating sheet member provided between the positive electrode of the grid electrode and the surface of the object to be heated is provided, the surface potential of the grid electrode is reduced by this sheet member, and the discharge phenomenon can be suppressed. it can. As a result, it is possible to prevent the efficiency of high-frequency heating from being lowered and the damage such as scorching on the surface of the object to be heated due to the discharge phenomenon.

Further, since the insulating sheet member is provided so as to cover the outer peripheral surfaces of the plurality of grid electrodes facing the surface of the object to be heated, even when steam is generated from the object to be heated by dielectric heating, The rise of water vapor to the grid electrode side is completely blocked by the sheet member, and water droplet adhesion due to dew condensation on the surface of the grid electrode is reliably prevented.

Further, since the above-mentioned insulating sheet member is provided so as to be able to wrap around or wind around the support board and the grid electrode, the sheet member interposed between the grid electrode and the surface of the heated object can be replaced. It can be done easily.

Further, since at least the outer peripheral surface of the positive electrode of the grid electrode is covered with the insulating film, the surface potential of each positive electrode is lowered by this insulating member, which is generated between the grid electrode and the surface of the object to be heated. The discharge phenomenon can be suppressed.

Furthermore, since the positive electrode is a tubular body having an outer peripheral surface covered with an insulating member and through which a fluid can flow, even when steam is generated from a heated object due to high-frequency heating, a high-temperature fluid is introduced into the electrode tube. Water droplets due to dew condensation on the surface of the grid electrode can be prevented by circulating it to heat the grid electrode, and the discharge suppressing effect is further improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of a grid electrode according to the present invention.

FIG. 2 is a cross-sectional view of a first embodiment of a grid electrode according to the present invention.

FIG. 3 is a diagram showing a shape of an air ejection hole provided in the grid electrode according to the first embodiment.

FIG. 4 is a vertical cross-sectional view of a second embodiment of a grid electrode according to the present invention.

FIG. 5 is a diagram showing the shape of air ejection holes provided in a grid electrode according to a second embodiment.

FIG. 6 is a view showing the shape of air ejection holes provided in a grid electrode according to a third embodiment.

FIG. 7 is a side view showing a schematic configuration of a high-frequency heating device provided with a grid electrode according to the present invention.

FIG. 8 is a front view showing a schematic configuration of a high-frequency heating device including a grid electrode according to the present invention.

FIG. 9 is a perspective view of an electrode portion of a high-frequency heating device having a fourth embodiment of a grid electrode according to the present invention.

FIG. 10 is a vertical cross-sectional view of an electrode part of a high-frequency heating device having a fourth embodiment of a grid electrode according to the present invention.

FIG. 11 is a cross-sectional view of an electrode part of a high-frequency heating device having a fourth embodiment of a grid electrode according to the present invention.

FIG. 12 is a cross sectional view of a fifth embodiment of a grid electrode according to the present invention.

FIG. 13 is a vertical cross-sectional view of a sixth embodiment of a grid electrode according to the present invention.

FIG. 14 is a vertical cross-sectional view of a seventh embodiment of a grid electrode according to the present invention.

FIG. 15 is a cross-sectional view of a seventh embodiment of a grid electrode according to the present invention.

FIG. 16 is a perspective view of an electrode part of a high-frequency heating device having an eighth embodiment of a grid electrode according to the present invention.

FIG. 17 is a side view of an electrode part of a high-frequency heating device having a ninth embodiment of a grid electrode according to the present invention.

FIG. 18 is a side view of an electrode part of a high-frequency heating device having a tenth embodiment of a grid electrode according to the present invention.

FIG. 19 is a side view of an electrode part of a high-frequency heating device having an eleventh embodiment of a grid electrode according to the present invention.

FIG. 20 is a side view of an electrode part of a high-frequency heating device having a twelfth embodiment of a grid electrode according to the present invention.

FIG. 21 is a side view of an electrode part of a high-frequency heating device having a thirteenth embodiment of a grid electrode according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 High frequency heating device 2 Conveyance part 21,21 'Conveying roller 3 High frequency generation part 31 High frequency generation device 32,32' 32 ", 33,33 ', 33" Grid electrode 321 Compressed air supply hole 321' Fluid discharge hole 322,322 ′ Connection part 323 Air ejection hole (gas ejection part) 324 Terminal plate 325 Insulation member 34, 34 ′ Upper plate 341 Positive terminal 342 Negative terminal 343, 344 Drive roller 345 Guide roller 346 Supply roller 347 Winding roller 35 35 Compressed air generator 36 Blower duct 37 Insulation pipe 38, 39 Supporting member 40, 40 'Electrode part 41 Sheet member P Heated body P1 Lumber P2 Decorative plate P3 Adhesive

Claims (10)

[Claims] 1. A grid electrode of a high-frequency heating device, which is arranged close to the surface of a heated object to form a high-frequency electric field on the surface layer of the heated object, wherein at least the positive electrode of the grid electrode is A grid electrode for a high-frequency heating device, which is a tubular body provided with a gas jetting portion for jetting a high-pressure gas supplied to the outside at least on the outer peripheral surface facing the surface of the object to be heated. 2. The grid electrode of the high frequency heating apparatus according to claim 1, wherein the gas jetting portion is a plurality of holes arranged discretely in the axial direction. 3. The grid electrode of the high frequency heating device according to claim 1, wherein the gas jetting portion is a slit having one or more than two slits. 4. The grid electrode for a high frequency heating device according to claim 1, wherein the positive electrode has an outer peripheral surface covered with an insulating member. 5. A grid electrode of a high-frequency heating device arranged in a pair or in two or more pairs in close proximity to the surface of the object to be heated so as to form a high-frequency electric field on the surface layer of the object to be heated, at least a positive electrode of the grid electrode. A grid electrode for a high-frequency heating device, comprising: an insulating sheet member interposed between the surface of the object to be heated and the surface of the object to be heated. 6. The plurality of grid electrodes are rod-shaped electrodes arranged on one surface of the support board at a predetermined interval,
The grid electrode of the high frequency heating device according to claim 5, wherein the insulating sheet member is attached to the support board so as to cover outer peripheral surfaces of the plurality of grid electrodes facing the surfaces of the objects to be heated. . 7. The plurality of grid electrodes are rod-shaped electrodes arranged on one surface of the support board at predetermined intervals,
The insulative sheet member is fed from a feeding roller provided at one end of the support plate in the arrangement direction of the grid electrodes so as to cover the outer peripheral surfaces of the plurality of grid electrodes facing the surface of the heated object. The grid electrode of the high frequency heating device according to claim 5, wherein the grid electrode is a roll film wound by a winding roller provided on the other end of the support board in the arrangement direction of the grid electrodes. 8. The plurality of grid electrodes are rod-shaped electrodes arranged on one surface of a supporting board at a predetermined interval,
The insulating sheet member is a belt-like film sheet rotatably provided around the support plate and the grid electrode so as to cover the outer peripheral surface of the plurality of grid electrodes facing the surface to be heated. The grid electrode of the high frequency heating apparatus according to claim 5, which is characterized in that. 9. The plurality of grid electrodes are rod-shaped electrodes arranged on one surface of the support board at predetermined intervals,
The grid electrode of the high frequency heating device according to claim 5, wherein the insulating sheet member is an insulating film that covers at least the outer peripheral surface of the positive electrode. 10. The grid electrode of the high frequency heating device according to claim 9, wherein the positive rod-shaped electrode is a tubular body through which a fluid can flow.