JPH08183098A - Welding jointing between fluororesin tubes - Google Patents

Abstract

PURPOSE: To attain jointing in a short time by installing a heat-welding type resin tube at a peripheral surface near a jointing part between fluororesin tubes, bringing a heat-resisting tubular body into close contact with the peripheral surface of the resin tube before covering, and carrying out welding with conduction heat from a conductive heat generating element, in heating and welding the jointing part. CONSTITUTION: In jointing fluororesin tubes 1, 1 with a heat-welding type resin tube 2, the heat-welding type resin tube 2 is first applied over a peripheral surface near a jointing part 1a between the fluororesin tubes 1, 1, and a heat- resisting tubular body 3 is brought into close contact with the peripheral surface before covering. A conductive heat generating element 4 is closely-disposed at the peripheral surface of the heat-resisting tubular body 3 so as to be attached and removed, and an opening and closing electromagnetic coupling coil L provided with a hinge box L4 pivoted by a hinge L3 is disposed so as to surround its periphery. The heat-welding type resin tube 2 is fused by the heat which the conductive heat generating element 4 generates through an alternating magnetic field from the electromagnetic coupling coil L to joint the fluororesin tubes 1, 1 each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororesin pipe or tube useful for constructing a pipe connecting portion for cleaning ultrapure water or a chemical liquid in a manufacturing site of semiconductors such as silicon single crystal wafers and liquid crystal panels. The present invention relates to a welding connection method.

[0002]

2. Description of the Related Art Conventionally, as a method for welding fluororesin members of this kind to each other, there has been a method described in Japanese Patent Publication No. 62-58898. In this conventional technique, a welding member made of a fluororesin and a member to be welded made of a fluororesin are prepared, and a welding surface of at least one of the members is preliminarily determined to have a softening point of not less than a melting point of the member. Preheating at temperature, and sliding relative speed between the above members is 3 to 2 per second.
A fusion bonding method for a fluororesin member, characterized in that the member to be welded is welded to the welding member by the heating and the heat generated by the sliding friction, which is set to 0 meters.

[0003]

The above-mentioned conventional technique requires a rotation source for rotating a fluororesin pipe or the like at a high speed, and cannot be easily carried out anywhere. Due to friction between the parts, scraped powder and dust are scattered to contaminate the inside of the pipe and its surroundings, and the clean room and the ultrapure water pipe are polluted with dust and cannot be used. Only applicable.

For this reason, at present, it is well known to heat and weld a joint portion such as a butting portion or a fitting portion of a fluororesin tube with a heating jig, but this one divides the tube connecting portion into half. The tube was surrounded by a cylindrical heating jig with a gap of about 2 to 3 mm, and the tubes were heated and melt-bonded by heat radiation.

Therefore, in this conventional example, due to the convection effect of the air in the gap, uneven heating occurs and good welding cannot be performed. Therefore, the heat source temperature is lowered in order to obtain uniform heating. There was a problem that it took time. SUMMARY OF THE INVENTION In order to eliminate the above-mentioned problems, an object of the present invention is to weld and connect fluororesin tubes to each other in a short time without unevenness without causing dust pollution.

[0006]

DISCLOSURE OF THE INVENTION The above-mentioned object of the present invention is to heat a joint between fluororesin tubes to heat the joint so that the peripheral surface near the joint between the fluororesin tubes is heated. A fusible resin pipe is attached, and a heat-resistant tubular body is further closely attached to the peripheral surface of the resin pipe, and a conductive heating element is detachably and closely arranged on the peripheral surface of the heat-resistant tubular body. The heat-welding property is applied to the peripheral surface in the vicinity of the joining portion by the conduction heat transmitted from the heat-resistant tubular body from the conductive heating element that surrounds the electromagnetically-coupling coil and is detachably arranged to receive heat by receiving an alternating magnetic field from the coil. This can be achieved by welding the resin pipes at the welding portion so that the fluororesin tubes can be connected to each other.

[0007]

First, the principle of heat generation of the conductive heating element according to the present invention applies the principle of a general electromagnetic cooker for heating and the principle of induction hardening. That is, due to the alternating magnetic field generated in the electromagnetic coupling coil (hereinafter simply referred to as a coil), an induced current according to the material of the conductive heating element having a short ring function disposed therein flows.

In the case where a conductive heating element having a split-cylindrical short ring action made of an iron plate is used, the induced currents include a short ring-like current and an induced overcurrent due to an induced voltage generated in the conductive heating element. There is.

Of these currents, the induced electric current causes the conductive heating element to have three losses, namely, self-resistance loss, contact resistance loss on the joining flange surface, and loss due to iron hysteresis phenomenon. A total of four heat generating actions, namely, heat generation due to the induced eddy current and heat generation due to eddy current resistance loss due to the induced eddy current, and the temperature is rapidly raised, and the conductive heating element can be used as a heat source. Then, when the coil current is cut off, the heating element now exhibits an air cooling function as a radiator, and cools the welded portion in a short time.

Next, the function of tube welding in the present invention will be described below. The heat-welding resin tube made of fluororesin, which is adhered to the joint between fluororesin tubes, is covered with a heat-resistant cylindrical body, and its peripheral surface can be rapidly heated by conduction heat from a conductive heating element that heats up by coil coupling. it can. The energy of this heating is directly transmitted through the heat-welding resin tube to the vicinity of the joint between the fluororesin tubes inside, and the vicinity of this joint is heated above the melting point and heated to the outer peripheral surface thereof. The inner surface of the fusible resin tube can be uniformly and firmly welded in a short time, and the ends of two or more fluororesin tubes can be connected to each other.

After this connection, the coil is opened from the hinge,
Remove the conductive heating element. In addition, poly-tetra-
When fluoroethylene (hereinafter abbreviated as "PTFE") is used, it is not completely welded due to its physical properties, and therefore the conductive heating element after welding can be easily removed.

Further, in the method of claim 2 according to the present invention, a heat resistant pipe made of PTFE, which covers the fitting portions of two fluororesin tubes having different diameters from each other, is provided around the conductive heating element. It is also possible to heat rapidly and evenly to the required welding temperature with the conduction heat. Then, the conduction heat transmitted through the heated heat-resistant pipe in its thickness direction serves as a heat source for heating the fitting portion, and the fitting portion is heat-conducted from its surroundings uniformly and rapidly above its melting point. It can be heated, and the fitting parts of two fluororesin tubes with different diameters can be evenly and rapidly welded uniformly.

[0013]

EXAMPLES Examples will be described with reference to the drawings. First, the basic configuration of the present invention is as shown in FIGS.
When heating the joints between the fluororesin tubes made of poly, fluoro, ethylene or the like to weld the joints, the ends of the fluororesin tubes 1 and 1 are brought into contact with each other as shown in the above figures. As shown in FIGS. 1 and 2, the heat-welding resin tube 2 is attached to the peripheral surface near the portion 1a through the state of FIG.

Then, PT is further formed on the peripheral surface of the resin pipe 2.
As shown in FIGS. 1 and 4, the FE heat-resistant tubular body 3 is tightly covered, and the peripheral surface of the heat-resistant tubular body 3 is a half-cut tubular conductive heating element 4 made of an iron plate and its flange. 4a is screwed and fixed in a detachable manner. Further, the periphery thereof is surrounded as shown in each of the above figures, and for example, the open / close type electromagnetic coupling coil L is detachably arranged by opening / closing the hinge.

That is, in this coil L, as shown in FIGS. 1 and 5, a large number of coil elements L0 made of a semicircular conductor having linear terminals L1 integrally projecting on both sides are conductively connected to their lower terminals L1. By connecting the flexible conductor L2 such as a braided wire so as to form a spiral coil, and firmly arranging it in the insulative hinge box L4 by the hinge L3 by the pivot as shown in each figure, the upper and lower coil elements are connected. Connect L0 and L0 so that they can be opened and closed.

Then, the conductive heating element 4 is fixed to the heat-resistant tubular body 3 with the flange 4a by means of a screw n, and is attached in the form of a tubular one-turn Shottling, and then the attached fluororesin tube is attached. 1, 1, etc. are stored in the lower coil element L0 as shown in FIGS.

Next, as shown by the arrow in FIG. 4, the upper coil element L0 is brought close to the lower coil element L0 together with the hinge box L4, and the conductive heat generation is performed by the insulating supporters L5 and L5 of each coil element L0. The body 4 is supported as shown in FIG. 6, and the coil elements L0 are joined at their linear terminals L1 to form a spiral coil form.

Then, this time, the terminals L1 and L1 in the above-mentioned joined state are respectively provided with conductive caps L6 and L6 from their tapered ends.
As shown by the chain line arrow in FIG. 7, each L6 is fitted with a click as shown in FIG. 6 to form an electromagnetic coupling coil L of, for example, 5 turns, which is extremely thick and relatively large.

Next, a current of about 5 to 10 volts and about 30 to 50 amperes at a frequency of 10 to 30 kilohertz can be applied to the coil L through its lead wires L7 and L7 at the time of use, for example, for about 1 minute. Prepare a high frequency power supply.

In addition to PTFE, a heat-resistant glass or ceramic cylinder can be used as the heat-resistant cylinder 3, and the material of the conductive heating element 4 is not limited to iron, but stainless steel or aluminum. The conductive heating element 4 may be a single-flange screw-fastened joint open / close type in which a flexible hinge portion is provided at one side edge, instead of screw-fastened joints of the both side flanges 4a.

The configuration example of the present invention is as described above, and its operation will be described below. When the conductive heating element 4 having the split ring-like short ring made of an iron plate is used,
The induced current includes a short-ring current and an induced overcurrent due to the induced voltage generated in the conductive heating element 4.

Of these currents, a current that flows through the conductive heating element 4 like a short ring due to an induced voltage, and the conductive heating element 4 has a self-resistance loss, a contact resistance loss at the joining flange surface, and a hysteresis phenomenon of iron. The heat generated by the three losses associated with the above and the heat generated by the eddy current resistance loss caused by the induced eddy current generate a total of four heat generating actions to rapidly raise the temperature, and the conductive heating element 4 is heated. Can be used as a heat source.
Then, when the current of the coil L is cut off, the heating element 4 now exhibits an air cooling function as a radiator, and cools the welded portion and the like in a short time.

Particularly in the present invention, the fluororesin tubes 1, 1
As shown in FIG. 2, the heat-welding resin tube 2 adhered to the joint portions 1a of the two is covered with the heat-resistant cylindrical body 3 and its peripheral surface is subjected to the alternating magnetic field from the coil L as shown in FIGS. It is possible to rapidly heat to the required welding temperature by the conductive heat from the conductive heating element 4 which generates heat. The heating energy is directly transmitted through the heat-welding resin tube 2 to the vicinity of the joint portion 1a between the fluororesin tubes 1 and 1 inside the heat-welding resin tube 2, and the heat-welding property is applied to the outer peripheral surface near the joint portion 1a. The inner surface of the resin tube 2 can be uniformly and firmly welded in a short time in the welding portion 1A as shown in FIG. 8, and the ends of two or more fluororesin tubes can be connected to each other and firmly connected.

After the welding, the conductive caps L6 and L6 are removed from the coil terminals L1 and L1, the coil L is opened from the hinge L3 as shown in FIG. 1, and the coil L is removed from the welded portion and cooled by the action of the radiator. The conductive heating element 4 is removed from the welded portion.

Further, the fluororesin tubes 1 and 1 according to the present invention are the same as the large diameter portions 2a on both sides of the heat-welding resin tube 2 as shown in FIG. Or different diameter fluororesin tubes 1, 1
To form two joints 1a, and one heat-resistant cylindrical body 3 made of PTFE is covered on the outside including these joints, and each joint in FIG. 1a and 1a can be welded.

Further, according to the present invention, as shown in FIG.
A heat resistant tubular body 3 made of PTFE is closely attached to the peripheral surface of the fitting portion 1b between two fluororesin tubes 1 and 1 having different diameters, and the heat resistant tubular body 3 is closely arranged. The fitting portion 1b can be heated and welded by the conduction heat transmitted through the heat-resistant cylindrical body 3. In this row, the heat-welding resin tube 2 is unnecessary.

[0027]

Since the present invention is configured as described above, it has the following effects. In heating the joint between the fluororesin tubes to weld the joint, the heat-welding resin pipe 2 is adhered to the peripheral surface in the vicinity of the joint 1a between the fluororesin tubes 1 and 1. The heat-resistant cylindrical body 3 is further closely attached to the peripheral surface of the heat-resistant cylindrical body 2 and
The heat-welding resin pipe is applied to the peripheral surface near the joint portion 1a by the conduction heat transmitted from the heat-resistant tubular body 3 from the conductive heating element 4 which generates heat by receiving the alternating magnetic field from the external coil L closely attached to the peripheral surface thereof. The first effect is that 2 can be evenly welded in a short time and the fluororesin tubes can be connected to each other.

Further, according to the present invention, since the ends of the fluororesin tube can be welded to each other only by heating, there is a second effect that no dust is generated, and the coil current is cut off after the welding so that the coil current can be removed. Since the conductive heating element 4 serves as a radiator and the welded portion can be rapidly air-cooled, the heating element 4 can be removed in a short time after welding, which is good in workability and is particularly effective when there are many welding points. There are also third and fourth effects.

Further, according to the second aspect, the heat-resistant tubular body 3 is adhered to the peripheral surface of the fitting portion 1b between the two fluororesin tubes 1, 1 having different diameters in a close contact state, and the heat-resistant tubular body is also attached. Three
Since the conductive heating element 4 closely arranged on the peripheral surface of the heat-dissipating member can heat and weld the fluororesin tubes in the fitting portion 1b to each other by the conduction heat transmitted to the heat-resistant tubular body 3, the heat-welding resin tube 2 itself can be connected. There is an industrial effect that it can be carried out more simply and cheaply without the need to use it.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a vertical sectional elevation view of the essential part of the embodiment of the present invention.

FIG. 3 is an exploded sectional view of a tube-related material according to an embodiment of the present invention.

FIG. 4 is a sectional view showing a combination of tube-related materials according to an embodiment of the present invention.

5 is a vertical sectional side view of what is shown in FIG.

FIG. 6 is an enlarged sectional view showing a state different from that shown in FIG.

FIG. 7 is a perspective view showing a state different from that shown in FIG.

FIG. 8 is a sectional view showing a welded state of the one shown in FIG.

FIG. 9 is a sectional view showing a welded state of another example of the present invention.

FIG. 10 is a sectional view showing a welding state of still another example of the present invention.

[Explanation of symbols]

 1 Fluororesin tube 1a Joining part 1b Fitting part 1A Welding part 2 Heat-welding resin tube 3 Heat-resistant cylinder 4 Conductive heating element 4a Flange (bonding part) L Electromagnetic coupling coil

Claims (2)

[Claims] 1. A method of heating a joint between fluororesin tubes to weld the joint, wherein a heat-welding resin tube 2 is attached to a peripheral surface near the joint 1a between the fluororesin tubes 1 and 1. Then, on the peripheral surface of the resin pipe 2, a heat-resistant cylindrical body 3
And the conductive heating element 4 is detachably and closely attached to the peripheral surface of the heat-resistant cylindrical body 3, and the electromagnetic coupling coil L is detachably arranged so as to surround the periphery thereof and detach from the coil L. The heat-weldable resin pipe 2 is welded to the peripheral surface near the joint 1a by the conduction heat transmitted from the heat-generating cylindrical body 3 from the heat-generating conductive body 4 that receives an alternating magnetic field to heat the welded portion 1A.
A method for welding and joining fluororesin tubes, which enables the fluororesin tubes to be joined together by welding. 2. A method for heating a joint between fluororesin tubes with a heat source to weld the joints, wherein a heat-resistant tubular body is provided on a peripheral surface of a fitting portion 1b between the fluororesin tubes 1, 1 having mutually different diameters. 3 is adhered in close contact with the heat-resistant cylindrical body 3, and a conductive heating element 4 is removably adhered to the peripheral surface of the heat-resistant cylindrical body 3, and the electromagnetic coupling coil L is removably arranged so as to surround the periphery thereof. The fitting portion 1b is welded at the welding portion 1A by the conduction heat transmitted through the heat-resistant tubular body 3 from the conductive heating element 4 which receives the alternating magnetic field from L to generate heat, and the fluororesin tubes having different diameters are connected to each other. A possible method for welding and joining fluororesin tubes together.