JP2001090896A - Organic solvent-impermeable joint for synthetic resin pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent an organic solvent from permeating from a joint part into an embedded pipe. SOLUTION: In this joint used to together join synthetic resin pipes 1, 1 each having at least one gas-impermeable resin layer 2 formed thereon by means of a joint body 4 mounted on outer surfaces of end parts of the pipes 1, 1, a sleeve pipe 3 made of a material not permeated with an organic solvent is fitted into pipe end parts of the pipes 1, 1 inserted in the joint body 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint for a synthetic resin pipe capable of reliably preventing an organic solvent from entering a buried pipe from a joint portion of the synthetic resin pipe buried in soil. .

[0002]

2. Description of the Related Art Polyethylene resin tubes do not have the effect of preventing the penetration of organic solvents. Therefore, when a polyethylene resin pipe for tap water is buried in soil contaminated with an organic solvent, the organic solvent permeates into the pipe and tap water in the pipe is contaminated with the organic solvent. If tap water is contaminated with an organic solvent, it may cause off-flavors, off-flavors, or harm health.

[0003] The polyethylene resin pipe has the following effects as compared with a conventionally used metal pipe. Excellent corrosion resistance to acids, alkalis and electricity. A completely integrated conduit can be constructed by the electrofusion joint. Has excellent flexibility. It stretches well against tension. Since it is lighter than a metal tube, it has excellent handling properties. It has excellent earthquake resistance because it has the effect of

[0004] As a means for solving the above-mentioned problems, a nylon-based resin which is relatively effective in preventing penetration of an organic solvent is used.
6 is wound around a polyethylene resin tube.

However, the method of winding nylon-6 around the polyethylene resin pipe is time-consuming and requires careful work of burying the pipe so that the nylon-6 does not peel off from the polyethylene resin pipe. It takes time.

Therefore, a synthetic resin tube which solves the above-mentioned problem is disclosed in Japanese Patent Application Laid-Open No. H11-10557.

This synthetic resin pipe is formed by extruding at least one gas-impermeable resin layer on a synthetic resin pipe (at least one of the inner surface, outer surface, and inner wall of the pipe). . The gas impermeable resin layer is
For example, it is made of an ethylene vinyl alcohol copolymer sold under the registered trademark “EVAL” by Kuraray Co., Ltd.

[0008]

According to the synthetic resin pipe having the gas-impermeable resin layer formed thereon, the penetration of the organic solvent from the pipe main body can be reliably prevented, but the pipe end abutting portion is not provided. No gas-impermeable resin layer is formed. Therefore, penetration of the organic solvent into the pipe from the pipe joint becomes a problem.

However, a joint for a synthetic resin pipe capable of preventing the penetration of an organic solvent into a pipe from a pipe joint has not yet been proposed. Therefore, its development is strongly desired.

Accordingly, an object of the present invention is to provide a joint for a synthetic resin pipe which can reliably prevent an organic solvent from entering a buried pipe from a pipe joint.

[0011]

According to the first aspect of the present invention,
In a synthetic resin pipe joint for joining synthetic resin pipes each having at least one gas-impermeable resin layer formed on the synthetic resin pipe via a joint body attached to an outer surface of a pipe end of the synthetic resin pipe, A sleeve tube made of a material through which an organic solvent does not penetrate is fitted into a tube end of the synthetic resin tube inserted into the joint body.

The invention according to claim 2 is characterized in that a stopper for positioning the tube end surface of the synthetic resin tube is formed on the central peripheral surface in the axial direction of the sleeve tube.

[0013] The invention according to claim 3 is characterized in that the stopper is formed by forming a part of the peripheral surface of the sleeve tube into a groove shape in the axial direction of the sleeve tube. .

The invention according to claim 4 is characterized in that the stopper comprises a ring-shaped flat plate fixed to the peripheral surface of the sleeve tube.

The invention according to claim 5 is characterized in that the sleeve tube is adhered to the inner surface of the tube end of the synthetic resin tube.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the joint for a synthetic resin pipe of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a pipe connection state by a synthetic resin pipe joint according to a first embodiment of the present invention, and FIG. 2 is a pipe connecting state by a synthetic resin pipe joint according to a second embodiment of the present invention. FIG. 3 is a sectional view showing a pipe connection state by a joint for a synthetic resin pipe according to a third embodiment of the present invention, and FIG.
FIG. 5 is an explanatory view of a current-carrying heating element in the joint main body, FIG.
FIG. 3 is a cross-sectional view showing a state in which a molten portion between a joint body and a pipe is hardened.

In FIG. 1, reference numerals 1 and 1 denote a synthetic resin pipe made of polyethylene or the like to be connected (hereinafter, a polyethylene resin pipe will be described as an example). And a gas-impermeable resin layer formed simultaneously with the extrusion of the resin tube. The gas impermeable resin layer 2 is made of nylon, ethylene vinyl alcohol copolymer resin, polyvinyl alcohol, polyamide, fluororesin, or polyvinylidene chloride.

The gas-impermeable resin layer 2 is formed not only in the pipe wall of the polyethylene resin pipes 1 and 1 but also on the outer surface of the pipe. If not, it may be formed on the inner surface of the tube.

Reference numeral 3 denotes a sleeve tube inserted into the end of the synthetic resin tube in the joint body. The sleeve tube 3 is made of a material such as stainless steel which has excellent corrosion resistance and does not penetrate the organic solvent. The outer diameter of the sleeve tube 3 has a tolerance such that the sleeve tube 3 has a slight interference fit with the inner diameter of the synthetic resin tubes 1 and 1 in order to provide an effect of preventing the organic solvent from penetrating into the tube. I have. The sleeve tube 3 may be bonded to the inner surfaces of the tube ends of the synthetic resin tubes 1 and 1 with an adhesive. By fitting the sleeve tube 3 into the tube ends of the synthetic resin tubes 1 and 1, it is possible to reliably prevent the organic solvent from permeating into the tubes from the joints of the synthetic resin tubes 1 and 1.

Reference numeral 4 denotes a joint body formed into a cylindrical shape so that the tube ends of the polyethylene resin tubes 1 and 1 are inserted. The joint body 4 is a polyethylene resin pipe 1 to be connected,
It is made of the same material as 1.

As shown in FIGS. 4 to 6, reference numeral 5 denotes a coil-shaped energizing heating element which is embedded in the inserted portion of the pipe end in the joint main body 4 and generates heat by energization. Reference numeral 6 denotes a pair of terminals provided on the outer surface of the joint body 4 for supplying electricity to the current-carrying heating element 5, and is electrically connected to the current-carrying heating element 5.

The electric heating element 5 is made of, for example, a micro metal fiber and an aramid fiber, has excellent flexibility and durability, and has almost the same electric heat characteristics as a nichrome wire. Therefore, there is no possibility of disconnection, and it can be easily embedded in the joint body 4. Electric heating element 5
The embedding method in the joint main body 4 can be performed by an injection molding method or the like by setting the current-carrying heating element 5 in a mold as in the related art. The energization heating element 5 may be formed in a net shape or a comb shape in addition to the coil shape. When the energizing heating element 5 is formed in a net shape, only one of the warp and the weft constituting the net is used as the energizing heating element to prevent a short circuit.

Reference numeral 7 denotes an indicator for managing a molten state of a contact portion between the polyethylene resin pipes 1 and 1 and the joint body 4. The indicator 7 is formed of a rod-like body inserted into a through hole formed in the joint body 4. When the contact portion between the polyethylene resin pipes 1 and 1 and the joint body 4 is melted by energization, the interface pressure at the contact portion increases, and the indicator 7 rises. By monitoring the raised state, the molten state of the polyethylene resin pipes 1 and 1 and the joint body 6 can be easily grasped from the outside. When the indicator 7 rises above the surface of the joint body 6 as shown in FIG. 6, it is determined that the contact portion between the polyethylene resin pipes 1 and 1 and the joint body 4 has completely melted, and the energization is stopped. .

According to the joint for a synthetic resin pipe of the first embodiment of the present invention configured as described above, the polyethylene resin pipes 1 and 1 are connected as follows.

First, the tube ends of the polyethylene resin tubes 1 and 1 are inserted into the joint body 4 with the sleeve tube 3 fitted in the tube ends. Then, the power supply connector 8 is fitted into the terminal 6, and electricity is supplied to the energizing heating element 5. Thereby, the inner surface of the joint body 4 and the polyethylene resin pipes 1, 1
Are heated and melted and fused to each other, so that the polyethylene resin tubes 1 and 1 are joined to each other via the joint body 4. The energization stops when the indicator 7 rises above the surface of the joint body 4.

If the joint body 4 and the sleeve tube 3 are adhered to each other with a water-insoluble adhesive, the pipe 1, 1
Intrusion of the organic solvent into the inside can be reliably prevented.

If the stopper for the synthetic resin tubes 1 and 1 is formed on the axially central peripheral surface of the sleeve tube 3, the sleeve tube 3
Positioning of the tube ends when the tube ends of the synthetic resin tubes 1 and 1 are inserted therein can be performed easily and easily.

As shown in FIG. 2, the stopper 9 may be formed by compressing a part of the peripheral surface of the sleeve tube 3 into a groove (U-shaped section) in the axial direction of the sleeve tube 3. Further, as shown in FIG. 3, the stopper 9 may be a ring-shaped flat plate fixed to the peripheral surface of the sleeve tube 3.

[0030]

As described above, according to the present invention, the synthetic resin tubes each having at least one gas-impermeable resin layer formed on the synthetic resin tube are mounted on the outer surface of the tube end of the synthetic resin tube. In a joint for a synthetic resin pipe to be joined to each other via a joint body to be formed, a sleeve pipe made of a material that does not penetrate an organic solvent is fitted into a pipe end of the synthetic resin pipe inserted into the joint body. By doing so, there is an industrially useful effect that the infiltration of the organic solvent from the pipe joint into the buried pipe can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a pipe connection state by a synthetic resin pipe joint according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a pipe connection state by a joint for a synthetic resin pipe according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a pipe connection state by a synthetic resin pipe joint according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram of a current-carrying heating element in a joint body.

FIG. 5 is a cross-sectional view showing a state where a contact surface between the joint body and the pipe is melted.

FIG. 6 is a cross-sectional view showing a state in which a molten portion between the joint body and the pipe is hardened.

[Explanation of symbols]

 1: Synthetic resin tube 2: Gas impermeable resin layer 3: Sleeve tube 4: Joint body 5: Electric heating element 6: Terminal 7: Indicator 8: Power connector 9: Stopper

Continuation of the front page (72) Inventor Michio Uzawa 1-2-1 Marunouchi, Chiyoda-ku, Tokyo F-term in Nihon Kokan Co., Ltd. (reference) 3H019 GA03

Claims (5)

[Claims] 1. A synthetic resin pipe having at least one gas-impermeable resin layer formed on the synthetic resin pipe is joined to each other via a joint body attached to a pipe end outer surface of the synthetic resin pipe. In the joint for a synthetic resin pipe, a sleeve pipe made of a material that does not penetrate an organic solvent is fitted into a pipe end of the synthetic resin pipe inserted into the joint main body, Joint for synthetic resin pipes that does not penetrate. 2. The joint for a synthetic resin pipe according to claim 1, wherein a stopper for positioning a pipe end surface of the synthetic resin pipe is formed on an axially central peripheral surface of the sleeve pipe. 3. The synthetic resin pipe according to claim 2, wherein the stopper is formed by forming a part of a peripheral surface of the sleeve pipe into a groove shape in an axial direction of the sleeve pipe. Fittings. 4. The joint according to claim 2, wherein the stopper comprises a ring-shaped flat plate fixed to a peripheral surface of the sleeve tube. 5. The joint for a synthetic resin pipe according to claim 1, wherein the sleeve pipe is bonded to an inner surface of a pipe end of the synthetic resin pipe.