JPH09257182A - Synthetic resin pipe and its connecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the renewal work of the outer circumferential surface at the end part of a synthetic resin pipe as simple as possible to make concoction work efficient when the synthetic resin pipes are connected with an EF joint. SOLUTION: When synthetic resin pipes A, A are connected with an EF joint 24 formed by arranging heater wires 30b, 30b in which a resin layer for melt bonding is formed in the outer circumference of a heater core wire are which are wound in a coil shape on the inner wall surface of a connecting pipe 26, the synthetic resin pipe A in which a resin film 22 comprising non- compatible resin to resin mainly forming the synthetic resin pipe A is bonded to the outer circumferential surface at the end part of the synthetic resin pipe A to which the EF joint is fit is used. Renewal surfaces 20, 20 are formed by peeling off the resin film 22 bonded to the outer circumferential surfaces at the end parts of synthetic resin pipes A, A, then the EF joint 24 is fit to the synthetic resin pipes A, A so as to stride each end part of the synthetic resin pipes A, A electricity is passed to the heater core wire of the EF joint 24, the resin layer is melted, then solidified to fill the resin of the resin layer in the gap between the connecting pipe 26 and each renewal surface 20 of the synthetic resin pipes A, A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin tube and a method for connecting the same, and more particularly, to a connecting tube for connecting a heater wire in which a resin layer for welding is wound around a heater core wire and wound in a coil shape. The present invention relates to a synthetic resin pipe connected by an EF joint arranged on the inner wall surface of the above and its connecting method.

[0002]

2. Description of the Related Art As a conventional method for connecting synthetic resin pipes,
The electro-fusion connection method shown in FIG.
(It may be called F method). This EF method is shown in FIG.
It is a method of connecting the synthetic resin pipes A and A by the EF joint shown in FIG. In the EF method, first, the heater wire 50 shown in FIG. 10 is attached to the outer peripheral surface of each end of the synthetic resin pipes A, A to be connected. The heater wire 50 is formed by winding the heater core wire 12 having a resin layer 14 made of a thermoplastic resin such as polyethylene resin formed on the outer periphery thereof in a coil shape. In this way, the EF joint is completed by mounting the synthetic resin connecting pipe 16 across the heater wire 50 mounted on the outer peripheral surface of each end of the synthetic resin pipes A and A. Next, the heater core wire 12 of the completed EF joint is energized to melt the resin layer 14. A part of the melted resin flows out to the outside of the heater wire 50 and is cooled to seal both outside parts of the heater wire 50. Due to such a seal, the internal pressure of the portion where the heater wire 50 is present rises, so that the molten resin comes into close contact with the inner wall surface of the connecting pipe 16 and the outer peripheral surface of each end of the synthetic resin pipes A and A, and further cools. By doing so, the two are closely connected.

[0003]

According to the EF method using the EF joint, the gap between the inner wall surface of the connecting pipe and the outer peripheral surface of the end of the synthetic resin pipe is utilized by utilizing the fluidity of the molten resin. Can be sealed, and the synthetic resin pipes can be tightly connected. However, since the resin forming the outer peripheral surface of the synthetic resin pipe is usually deteriorated by being exposed to direct sunlight, air, etc., the resin forming the heater wire 50 at the connecting portion of the synthetic resin pipe connected by the EF method. The connection strength between the resin obtained by melting and cooling and solidifying the layer 14 and the outer peripheral surface of the synthetic resin pipe is low,
Both are easy to peel off. Therefore, as shown in FIG. 11, the outer peripheral surface of the end portion of the synthetic resin pipe A is scraped off by a scraping tool 100 to form a renewal surface, and the heater wire 50 is attached to the renewal surface before melting the resin layer 14. Then, by cooling and solidifying, it is possible to prevent the resin solidified by cooling and the outer peripheral surface of the synthetic resin pipe from peeling off.

However, when the synthetic resin pipe is connected by the EF method, the renewal work for scraping off the outer peripheral surface of the end portion of the synthetic resin pipe must be performed immediately before the connection work in order to prevent deterioration of the renewed surface. In addition, when the renewal work is performed by polishing using a grinder or sandpaper, the synthetic resin pipe may be deformed by frictional heat. For this reason, such update work has delayed connection work. In particular, with a large diameter synthetic resin pipe having a pipe diameter of 300 mm or more, the renewal work with the shaving tool 100 becomes more difficult. Then, the subject of this invention is E
When connecting synthetic resin pipes using the F joint,
It is an object of the present invention to provide a synthetic resin pipe and a method for connecting the synthetic resin pipe, by which the work of updating the outer peripheral surface of the end portion of the synthetic resin pipe can be made as simple as possible and the connection work can be performed efficiently.

[0005]

As a result of studies to solve the above-mentioned problems, the present inventor has found that a resin film made of a resin incompatible with the resin forming the synthetic resin pipe is formed on the outer peripheral surface of the synthetic resin pipe. It is possible to prevent deterioration of the resin that forms the outer peripheral surface of the synthetic resin pipe, and the resin film can be easily peeled from the outer peripheral surface of the synthetic resin pipe, so that the outer peripheral surface of the end of the synthetic resin pipe can be removed immediately before connection work. They have found that they can be easily updated, and have arrived at the present invention. That is, the present invention relates to a synthetic resin tube in which a heater resin wire layer for welding is formed on the outer periphery of a heater core wire and wound around in a coil shape is connected by an EF joint formed on the inner wall surface of the connection tube. In addition, a resin film made of a resin incompatible with the resin mainly forming the synthetic resin pipe is adhered to at least the outer peripheral surface of the end of the synthetic resin pipe to which the EF joint is mounted. It is in a characteristic synthetic resin pipe.

Further, according to the present invention, two heater wires, each having a resin layer for welding formed on the outer periphery of the heater core wire and wound in a coil shape, are arranged on the inner wall surface of the connecting pipe by an EF joint. When connecting the synthetic resin pipe, the synthetic resin pipe is incompatible with the resin mainly forming the synthetic resin pipe at least on the outer peripheral surface of the end of the synthetic resin pipe to which the EF joint is mounted. A synthetic resin pipe in which a resin film made of a resin is adhered is used. After the resin film adhered to the outer peripheral surface of each end of the synthetic resin pipe is peeled off to form a renewed surface, the EF joint is attached to the synthetic resin pipe. By mounting the heater core wire of the EF joint by energizing the heater core wire to melt the resin layer and then cooling and solidifying, the gap is formed between the connecting pipe and each renewal surface of the synthetic resin pipe. It is special to fill with resin In connection of the synthetic resin tube according to. In the present invention, a resin film made of a polypropylene resin is adhered to the outer peripheral surface of the synthetic resin pipe formed mainly of polyethylene resin or vinyl chloride resin, thereby forming a resin film from the outer peripheral surface of the synthetic resin pipe. It can be easily peeled off.

According to the present invention, the resin forming the outer peripheral surface of the end portion of the synthetic resin pipe is shielded from direct sunlight, air, etc. by the resin film which is in close contact with the outer peripheral surface of the end portion, and therefore is deteriorated. To be prevented. Further, since the resin forming the resin film is incompatible with the resin mainly forming the synthetic resin pipe, the resin film can be easily peeled from the outer peripheral surface of the end portion of the synthetic resin pipe. As a result, the end outer peripheral surface of the synthetic resin pipe can be easily renewed by peeling off the resin film adhered to the end outer peripheral surface of the synthetic resin pipe immediately before connecting the synthetic resin pipes. Therefore, at the connection portion of the synthetic resin pipe connected by the EF method, the resin obtained by melting and cooling and solidifying the resin layer of the heater wire and the renewed surface of the synthetic resin pipe can be brought into close contact with each other, and peeling between the two can be prevented.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The synthetic resin pipe used in the present invention is made of a resin which is incompatible with the resin mainly forming the synthetic resin pipe A on the outer peripheral surface of the synthetic resin pipe A, as shown in FIG. The resin film 22 is closely attached. Such synthetic resin pipe A
As the resin mainly formed of, polyethylene resin,
The synthetic resin pipe A can be easily manufactured by using a thermoplastic resin such as a vinyl chloride resin. In addition, the resin film 2
2 may be made of a resin that is incompatible with the resin that mainly forms the synthetic resin pipe A, and has a thickness of 0.5 m.
When it is m or less, it is easy to adhere to the outer peripheral surface of the synthetic resin pipe A, which is preferable. The resin film 22 is made of polypropylene resin when the resin mainly forming the synthetic resin pipe A is polyethylene resin or vinyl chloride resin.
Can be preferably used. The synthetic resin pipe A shown in FIG. 1 uses a conventionally known mold for a two-layer pipe, forms a cylinder of polyethylene resin or vinyl chloride resin, and forms a resin film 22 on the outer peripheral surface of the cylinder. Thus, the synthetic resin pipe A can be manufactured. The term "incompatible" as used herein means that when two or more kinds of resins in a fluid state are mixed with each other, the mixed state maintains a non-homogeneous phase state.

Since the resin film 22 adhered to the outer peripheral surface of the synthetic resin pipe A shown in FIG. 1 is made of a resin which is incompatible with the resin mainly forming the synthetic resin pipe A, the outer periphery of the synthetic resin pipe A is large. Easy to peel off from the surface. Therefore, immediately before mounting the EF joint used for connecting the synthetic resin pipe A, the resin film 22 on the outer peripheral surface of the end portion of the synthetic resin pipe A is peeled off as shown in FIG. The renewal surface 20 can be formed by exposing the outer peripheral surface of the end portion covered with.
The renewal work of peeling off the resin film 22 to form the renewal surface 20 is extremely easy as compared with the renewal work of scraping off the outer peripheral surface of the end portion of the synthetic resin pipe shown in FIG. Can be done quickly.

In this way, the synthetic resin pipes A, A are connected to the renewal surface 20 obtained by renewing the outer peripheral surfaces of the end portions of the synthetic resin pipes A, A to be connected.
EF joint 2 shown in FIG. 3 so as to straddle each end of the
4 is attached. The EF joint 24 is a cylindrical body made of a resin such as polyethylene resin, and has a groove 2 on the inner wall surface.
Connecting pipe 26 around which 8a and 28b are provided, and concave groove 28a,
28b and heater wires 30a and 30b arranged inside. The recessed grooves 28a and 28b can be formed by cutting a cylindrical body having an inner wall surface that is a smooth surface by molding with resin or the like. In addition, the heater wires 30a and 30b are the same as those in FIG.
Similar to the heater wire 50 shown in FIG. 3, the heater core wire 12 having the resin layer 14 made of a thermoplastic resin such as polyethylene resin formed on the outer circumference is wound in a coil shape.
The resin layer 14 is formed of a resin that is compatible with the resin forming the connecting pipe 26 and the resin mainly forming the synthetic resin pipe A, so that the resin layer 14 is connected to the resin melted and cooled and solidified. It is preferable because the pipe 26 and the synthetic resin pipe A can be prevented from being separated from the renewed surface 20.

The outer diameters of the heater wires 30a and 30b are set to be slightly larger than the inner diameters of the concave grooves 28a and 28b.
When the heater wires 30a and 30b are arranged in the concave grooves 28a and 28b, the heater wires 30a and 30b are arranged in the concave grooves 28a and 28b.
30b is formed so as to fit tightly. The inner diameters of the heater wires 30a and 30b are substantially the same as the inner diameter of the connecting pipe 26. The heater wires 30a and 30b are connected to the groove 28
In order to arrange each of a and 28b, first, the coiled heater wire 50 shown in FIG. 10 is replaced with the cylindrical heater wire 3 shown in FIG.
Set to 0. The heater wire 30 corresponds to the heater wire 50 (see FIG.
The outer periphery of (0) is applied with an electric iron and rubbed in the axial direction to bond the resin layers 14 to each other to form a tubular shape.
Next, the tubular heater wire 30 is deformed into a heart shape in cross section to reduce its diameter, and then inserted into the connecting pipe 26 in a reduced diameter state, and opened at the positions of the concave grooves 28a and 28b. , 28b can be fitted with the heater wire 30.

Each of the lead wires electrically connected to the respective heater core wires 12 of the heater wires 30a and 30b fitted in the recessed grooves 28a and 28b is bored at a portion of the connecting pipe 26 on the open end side. Through the through holes 32a and 32b.
By thus forming the through holes 32a and 32b on the end side of the connecting pipe 26, it is possible to prevent the seal from being broken from the through holes 32a and 32b. Further, it is preferable to provide small holes 34a and 34b for indicating, which communicate with the concave grooves 28a and 28b, on the end side of the connecting pipe 22. Due to these small holes 34a, 34b, the concave grooves 28a, 2
This is because the air can be discharged from 8b and the surplus molten resin can be released.

When connecting the synthetic resin pipes A, A using the EF joint 24 shown in FIG. 3, first, as shown in FIG. 2, from the outer peripheral surface of each end of the synthetic resin pipe A to which the EF joint 24 is mounted. The resin film 22 is peeled off, and the renewal surface 20 having a predetermined length
To form Then, the ends of the synthetic resin pipes A and A are
As shown in FIG. 5, the EF joint 24 is inserted from both ends by a predetermined length and the end faces are butted. At this time, since the heater wires 30a and 30b are incorporated in the EF joint 24 in advance, the heater wires 30a and 30b are brought into contact with predetermined positions of the renewal surfaces 20 and 20 only by inserting the ends of the synthetic resin pipes A and A. Is installed in. After that, by energizing the heater wires 30a and 30b, the resin layer 14 of the heater wires 30a and 30b is melted, and the molten resin is formed between the inner wall surface of the connection pipe 26 and the renewed surfaces 20 and 20 of the synthetic resin pipes A and A. Gap (concave grooves 28a, 28
(including b). Therefore, the grooves 28a, 28b
Since the gap including is reliably sealed by the molten resin and is hermetically closed, after the molten resin fills the sealed space, excess molten resin enters the small holes 34a and 34b together with air (FIG. 6). Therefore, the small holes 34a, 34
When it is confirmed that the molten resin has been filled up to the inside of b, the heater wires 30a and 30b are stopped from being energized, the molten resin is cooled and solidified, and then the lead wire protruding from the connecting pipe 24 is cut. And remove.

As described above, the resin that has flowed into the gap between the inner wall surface of the connecting pipe 26 and the renewal surfaces 20 and 20 of the synthetic resin pipes A and A and is cooled and solidified has the same properties as the non-degraded synthetic resin pipes A and A. It adheres to the renewal surfaces 20, 20. Moreover, the gap is
Since the gap is narrow, a slight amount of molten resin flows in, so that the outer peripheral surfaces of the end portions of the synthetic resin pipes A, A are renewed surfaces 2.
Coupled with the fact that it is 0 or 20, the gap can be easily and surely sealed. As a result, the synthetic resin pipes A, A are connected via the resin that adheres to the inner wall surface of the connection pipe 24 and the renewal surfaces 20, 20, and the adhesion between the renewal surfaces 20, 20 and the resin is also good. Therefore, the peeling phenomenon between the both can be prevented. Therefore, the synthetic resin pipes A, A can be reliably connected. By using the EF joint 24 shown in FIG. 3, it is possible to sufficiently cope with the connection of a synthetic resin pipe having a pipe diameter of 300 mm or more. For example, the pipe diameter is 10
Even if it is a synthetic resin pipe with a large diameter of 00 mm or more, the resin film 2
By peeling 2 from the outer peripheral surface of the end of the synthetic resin pipe, the renewal surface 20 can be easily formed, and the heater wires 30a and 30b can be arranged at predetermined positions of the renewal surfaces 20 and 20 without displacement. It can be suitably used for connecting a large-diameter synthetic resin pipe.

An EF joint 36 shown in FIG. 7 can be used instead of the EF joint 24 shown in FIG.
The EF joint 36 is provided with a wide concave groove 40 on the inner wall surface of the connecting pipe 38 so as to extend over the pipe ends of the synthetic resin pipes A, A to be connected, and extends over substantially the entire length of the concave groove 40. The heater wire 30 is incorporated. Such E shown in FIG.
Even in the F joint 36, the EF joint 24 shown in FIG.
The synthetic resin pipes A, A can be connected in the same procedure as. Since the synthetic resin pipe A shown in FIG. 1 is used as the synthetic resin pipe to be connected as in the present invention, the work of updating the outer peripheral surface of the end portion of the synthetic resin pipe can be made as simple as possible. Even if the EF joint shown in FIG. 9 which has been conventionally used is used, the synthetic resin pipes A and A can be reliably and easily connected. At this time, the heater wire 50
Alternatively, the heater wire 42 shown in FIG. 8 can be used. The heater wire 42 has a heater core wire 46 built in a tubular body 44 formed to have an inner diameter into which the end of the synthetic resin pipe A can be inserted. In addition, in the synthetic resin pipe A shown in FIGS. 1, 2, and 5, the resin film 22 is adhered to the entire outer peripheral surface of the synthetic resin pipe A, but the end of the synthetic resin pipe A to which the EF joint is attached is attached. It may be only the outer peripheral surface.

[0016]

According to the present invention, even for a synthetic resin pipe having a large diameter, it is possible to renew the end outer peripheral surface of the synthetic resin pipe immediately before connecting the synthetic resin pipe as much as possible. . Therefore, the connecting work of the synthetic resin pipe by the EF method can be easily and surely performed.

[Brief description of drawings]

FIG. 1 is a partial sectional front view showing an example of a synthetic resin pipe according to the present invention.

FIG. 2 is an explanatory diagram illustrating a state in which a resin film adhered to an outer peripheral surface of an end portion of the synthetic resin pipe illustrated in FIG. 1 is peeled off.

FIG. 3 is a vertical sectional view showing an example of an EF joint used in the present invention.

4 is a vertical cross-sectional view showing an example of a heater wire used in the EF joint shown in FIG.

FIG. 5 is a partial cross-sectional view showing a state in which the EF joint shown in FIG. 3 is attached to a synthetic resin pipe to be connected.

FIG. 6 is a partial cross-sectional view showing a connected state of a synthetic resin pipe.

FIG. 7 is a partial cross-sectional view showing another example of the EF joint.

FIG. 8 is a vertical sectional view showing another example of a heater wire.

FIG. 9 is an explanatory diagram for explaining a conventional connection method.

FIG. 10 is a vertical cross-sectional view showing a heater wire used in a conventional connecting method.

FIG. 11 is an explanatory diagram for explaining a conventional method for updating the outer peripheral surface of the end portion of the synthetic resin pipe.

[Explanation of symbols]

 A synthetic resin pipe 12,46 heater core wire 14 resin layer 20 renewal surface 22 resin film 26,38 connection pipe 24,36 EF joint 28a, 28b, 40 concave groove 30, 30a, 30b, 42, 50 heater wire 32a, 32b transparent Hole 34a, 34b Small hole

Claims (3)

[Claims] 1. A synthetic resin tube in which a heater resin wire for welding is formed on the outer circumference of a heater core wire and wound around in a coil shape is connected by an EF joint formed on the inner wall surface of the connecting tube. And a resin film made of a resin incompatible with the resin mainly forming the synthetic resin pipe is adhered to at least the outer peripheral surface of the end of the synthetic resin pipe to which the EF joint is mounted. And synthetic resin tube. 2. An outer peripheral surface of an end portion of a synthetic resin pipe formed mainly of polyethylene resin or vinyl chloride resin,
The synthetic resin tube according to claim 1, wherein a resin film made of polypropylene resin is closely attached. 3. A synthetic resin pipe is formed by an EF joint formed by arranging a heater wire, in which a resin layer for welding is formed on the outer periphery of a heater core wire and wound in a coil shape, on an inner wall surface of a connecting pipe. As a synthetic resin pipe, a resin made of a resin that is incompatible with the resin that mainly forms the synthetic resin pipe at least on the outer peripheral surface of the end of the synthetic resin pipe to which the EF joint is mounted. Using a synthetic resin pipe having a film adhered thereto, the resin film adhered to the outer peripheral surface of each end of the synthetic resin pipe is peeled off to form a renewal surface, and then the EF joint is attached to each end of the synthetic resin pipe. It is mounted so as to straddle, and then the heater core wire of the EF joint is energized to melt the resin layer and then to be cooled and solidified, thereby filling the gap between the connecting pipe and each renewal surface of the synthetic resin pipe with the resin. A synthetic tree characterized by How to connect the fat pipe.