JPH05106769A - Connection structure between pipe and pipe joint - Google Patents

Abstract

PURPOSE:To facilitate connection of a metal pipe with its inner face coated with resin with a sufficient anti-pulling force without application of threading work to a pipe end by fitting a rubber packing between the outer face of cylindrical core part of synthetic resin compact and the inner face of the pipe end so as to performing work for preventing water from passing through to the pipe end face and pipe outer part. CONSTITUTION:A synthetic resin form 1 having a cylindrical core member 11 is fixed in a pipe joint main body 2 and a pipe end insertion gap 3 is formed. A female threaded groove 21 is formed on the inner ace of end of the pipe joint main body 2 and the rubber packing fitting groove 12 is formed on the outer face of the cylindrical core part 11. The pipe end (b) of a metal pipe with its inner face being coated with resin B is inserted into the gap 3 and compressed with the inner face (b1) of the pipe end. A lock ring 5 of C type in section has at its outer circumferential face a male thread groove 51 threaded to the female thread groove 21 of a pipe joint A and at its inner circumferential face a thread groove 52 fitted forcedly to the outer face (b2) of the pipe end, and the thread groove 52 at the inner face is forcedly fitted to the outer face (b2) because it is reduced in its diameter when threaded to the female thread groove 21 of the pipe joint A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for connecting a pipe and a pipe joint, which is used for connecting an inner surface resin-coated metal pipe or an inner surface-outer surface resin-coated metal pipe.

[0002]

2. Description of the Related Art In metal pipes used in the fields of water supply and hot water supply, inner surface corrosion protection is required for water supply and hot water supply, and inner surface resin-coated metal pipes are often used.

When connecting this inner surface resin-coated metal pipe,
Not only stopping the water flow inside the pipe but also stopping the water at the boundary between the resin inner layer and the metal pipe at the end face of the pipe, it is necessary to prevent water from entering the boundary between the resin inner layer and the metal pipe. Is essential to prevent and eliminate that delamination.

Further, it is also necessary to provide the connecting portion with pull-out strength capable of sufficiently dealing with an external load such as a thrust load and vibration based on water pressure in the pipe. Therefore, conventionally, as shown in FIG. 7 (a), a synthetic resin molded body 1'having a tubular core portion 11 'is fixedly mounted in a pipe joint body 2'having an internal thread groove 21'. Putty-like sealant 4 such as sealant in the pipe end portion insertion gap 3'of the pipe joint A'where the pipe end portion insertion gap 3'is formed between the tubular core portion and the pipe joint body.
1'is filled and a male screw groove 51 'is engraved on the metal pipe outer surface of the inner surface resin-coated metal pipe end portion b', and this pipe end portion is connected to the pipe joint A '.
Is screwed into the female thread groove 21 'of FIG. 1 through a seal tape 42', and the tip end surface e'of the inner surface resin-coated metal tube is put with a putty-like sealant 41 'in the inner portion of the tube end insertion gap 3'. It is sealed.

According to this structure of the connecting portion, the putty-like sealant 41 'and the tape seal 42' engaged with the screwing portion stop the passage of water in the pipe to the outside. The putty-like sealant 41 'that surrounds the end surface e'stops water at the boundary between the resin coating layer on the tube end surface e'and the metal pipe.

Further, the withdrawal strength is assured by the screw engagement between the pipe end and the pipe joint.

[0007]

However, in the above connecting structure, it is necessary to form a thread groove on the outer surface of the metal pipe at the end of the pipe, and the pipe length must be adjusted and cut to connect the pipe on site. When it is necessary to perform thread groove processing on site, such as when it must be done, the connection work becomes difficult because the processing is troublesome.

Conventionally, when connecting a metal pipe using a pipe joint having a female thread groove, as shown in FIG. 7B, a female thread of the pipe joint is formed in order to eliminate the thread groove processing of the end portion of the metal pipe. A lock ring 5'in which a male thread groove 51 'screwed into the groove 21' is engraved on the outer surface, a diameter-reducing slit 54 'is formed on the tip portion, and a thread groove 52' is engraved on the inner surface of the tip portion, It is possible to screw it into the female thread groove 21 'of the joint and reduce the diameter of the tip by screwing the lock ring 5'to make the thread groove 52' on the inner surface of the tip difficult to fit into the outer surface of the metal pipe end b '. It is known (for example, Japanese Patent Application Publication No. Sho 49-752).
4).

However, in the connection structure between the pipe joint and the metal pipe, it is inevitable that a gap remains at the connection interface between the lock ring and the end of the metal pipe (the female thread of the lock ring and the pipe joint body). At the threaded interface with the groove, it is possible to eliminate the gap by engaging a seal tape.) The connecting structure between this pipe joint and the metal pipe is shown in FIG. When used to bond the pipe joint body and the metal pipe of the inner surface resin-coated metal pipe in the pipe connection structure shown, the putty-like sealant that is pressurized by the water pressure inside the pipe causes the binding interface between the lock ring and the metal pipe. It is difficult to maintain the waterproof property.

An object of the present invention is to provide sufficient pulling-out resistance without threading the pipe end portion, and also to stabilize the water stoppage to the resin resin-coated metal pipe end face of the inner surface of the pipe and to the outside. Another object of the present invention is to provide a connecting portion structure between a pipe and a pipe joint, which can easily connect the inner surface resin-coated metal pipe.

[0011]

According to the structure for connecting a pipe and a pipe joint of the present invention, a synthetic resin molded body having a tubular core portion is fixedly mounted in a pipe joint body to form an outer surface of the tubular core portion. The pipe end is inserted into the pipe end insertion gap of the pipe joint in which a pipe end insertion gap is formed between the pipe joint body inner surface and the pipe core main body outer surface, and the tubular core portion outer surface and the pipe end portion inner surface are provided. Rubber packing is installed,
The structure is characterized in that the pipe joint body and the pipe outer surface are bound by a lock member.

[0012]

[Function] Rubber packing is mounted between the outer surface of the tubular core portion and the inner surface of the pipe end portion of the synthetic resin molded body that is fixedly installed in the pipe joint body. Irrespective of the watertightness, water is stopped from passing through the pipe end surface and inside the pipe. Therefore, there is a lock ring between the outer surface of the pipe end and the pipe joint,
Even if the gap remains, these water stops can be stably held.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view showing an embodiment of the present invention.

In FIG. 1, A is a pipe joint, and a synthetic resin molded body 1 having a tubular core portion 11 is fixed in a pipe joint body 2 so as to be located between the inner surface of the pipe joint body and the outer surface of the tubular core portion. A gap 3 for inserting the pipe end portion is formed in. Reference numeral 21 is a female screw groove formed on the inner surface of the end of the pipe joint body 2, and 12 is a rubber packing mounting groove provided on the outer surface of the tubular core portion 11. Reference numeral B denotes an inner surface resin-coated metal pipe, the pipe end portion b of which is inserted into the pipe end portion insertion gap 3 of the pipe joint A. Reference numeral 4 denotes a rubber packing, which is mounted in the rubber packing mounting groove 12 of the tubular core portion 11 and is compressed at the tube end inner surface b ₁ . Reference numeral 5 is a lock ring having a C-shaped cross section and capable of reducing its diameter.
(A) of FIG. 2 (side view showing a part in cross section) and (b)
As shown in the (front view), an outer peripheral surface is provided with a male thread groove 51 that is screwed into the female thread groove 21 of the pipe joint A, and an inner peripheral surface is provided with a thread groove 52 into which the pipe end portion outer surface b ₂ is hard to be inserted. Have In the lock ring 5, the diameter of the pipe joint A is reduced by being screwed into the female thread groove 21 so that the thread groove 52 on the inner surface is embedded in the outer surface b ₂ of the tube end portion.

To assemble the above-mentioned connecting portion structure, the rubber packing 4 is attached to the tubular core portion 11 of the synthetic resin molded body 1 of the pipe joint A, the lock ring 5 is passed through the pipe B, and then the pipe end is inserted. The portion b is inserted into the gap 3 for inserting the pipe end portion of the pipe joint A, and the rubber packing 4 is compressed on the inner surface b ₁ of the pipe end portion. Next, the lock ring 5 is pulled back, and the lock ring 5 is screwed into the female thread groove 21 of the pipe joint A to reduce the diameter so that the thread groove 52 on the inner surface of the lock ring is hard to fit on the outer surface b ₂ of the pipe end portion.
This completes the assembly.

The lock ring 5 can be easily screwed in by rotating only the lock ring 5 with a wrench or the like, and it is not necessary to relatively rotate the pipe joint A and the pipe B, so that the rubber packing is used. The twisting of the rubber packing 4 can be avoided, and the rubber packing 4 can be mounted in a good condition.

In the structure of the connecting portion between the pipe and the pipe joint,
The water stopping ability is determined by the water stopping ability of the rubber packing 4,
This waterproofness is not affected by the remaining gaps at the binding interface between the pipe joint A and the lock ring 5 and at the binding interface between the lock ring 5 and the outer surface b _{2 of the} pipe end portion. By setting the contact pressure, the contact length and the like with the pipe end inner surface b _{1 and the} tubular core outer surface c according to the pipe water pressure, water can be stably stopped in the pipe.

In the above description, the pipe to be connected B can be used as long as it has an anticorrosive coating layer on at least the inner surface of the metal pipe, and not only the inner surface resin-coated metal tube but also the inner and outer surface resin-coated metal tube, for example, the inner and outer surfaces. A vinyl chloride resin-coated steel pipe can also be used.

In the above, in addition to metal products such as iron, synthetic resin products such as nylon can be used for the pipe joint body 2.
The synthetic resin molded body 1 in the pipe joint body 2 can be molded by injection molding in which a mold is incorporated in the pipe joint body 2, and for this resin, for example, polyethylene can be used.

In order to increase the binding strength between the pipe joint body 2 and the synthetic resin molded body 1, as shown in FIG. 3, a protrusion portion 22 is provided in the center of the inner surface of the pipe joint body 2, and the protrusion portion 22 is provided.
It is desirable that the synthetic resin molded body 1 is hard to be embedded.

In the above, the rubber packing 4 is shown in FIG.
As shown in FIG. 3, a tubular rubber packing having a flange portion 41 at its tip is used. The tubular portion 40 of the rubber packing 4 is inserted into the pipe end portion b, and the pipe end portion b is connected to the pipe of the pipe joint A. It is also possible to insert the rubber packing tubular portion 40 into the end insertion gap 3 and compress the rubber packing tubular portion 40 with the tubular core portion 11. The material of the rubber packing 4 is selected according to the liquid quality of the water passing through the pipe, the temperature, etc. In the case of water, ethylene / propylene rubber, chloroprene rubber, fluororubber or the like can be used.

In the above, as shown in FIG. 5, the lock ring 5 has a plurality of taper parts (usually 6) for reducing the diameter in the taper portion having the male thread groove 51 screwed into the female thread groove of the pipe joint body. Slits 53, ... Are provided, and a plurality of protrusions 53, ..
Those provided with can also be used. For example, brass can be used as the material of the lock ring 5.

The tightening structure of the lock ring 5 is as follows.
An appropriate configuration can be used as long as the lock ring 5 can be tightened between the outer surface of the pipe end portion and the pipe joint without relatively rotating these both members. For example, as shown in FIG. Screw-type pressing fitting 61 as shown, or FIG.
Bolt tightening retainer 62 as shown in (b)
The lock ring 5 may be tightened with.

[0024]

The structure of the connecting portion between the pipe and the pipe joint according to the present invention is as described above, and the inner surface of the pipe end is sealed from the water flow in the pipe by the rubber packing, and the outer surface of the pipe end portion is sealed. Regardless of the watertight state between the pipe joint and the pipe joint, water can be stopped against the pipe end surface of the water passage in the pipe and water outside the pipe of water passage inside the pipe, so there is no seal between the pipe joint and the outer surface of the pipe end. -The binding by the flexible lock ring has no effect on these water stops, and when the coupling by the lock ring is made between the pipe joint and the outer surface of the pipe end, the pipe joint and the pipe are relatively Since it does not need to be rotated and can be installed satisfactorily without twisting the rubber packing, it is possible to use the lock ring method instead of the method of screwing the male thread groove of the pipe end into the female thread groove of the pipe joint. Nevertheless, with the resin coating layer on the inner surface of the resin coated metal pipe It can be connected to the inner surface resin-coated metal tube and the water stop with sufficient water tightness the boundary portion between the genus pipe from pipe water flow. Therefore, it is not necessary to form the thread groove on the metal pipe at the end portion of the inner surface resin-coated metal pipe, and the pipe connecting work can be simplified.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an embodiment of the present invention.

FIG. 2A is a side view partially showing an example of a lock member used in the present invention in section, and FIG. 2B is a front view showing the lock member.

FIG. 3 is a partial cross-sectional view showing another example of the pipe joint used in the present invention.

FIG. 4 is a partial cross-sectional view showing another embodiment of the present invention.

FIG. 5 is a side view showing a part of a cross-section of another example of the lock member used in the present invention.

FIG. 6 is a partial cross-sectional view showing another example different from the above of the tightening structure for the lock member used in the present invention.

FIG. 7 is a partial cross-sectional view showing another conventional example.

[Explanation of symbols]

 1 Synthetic Resin Molded Body 11 Cylindrical Core Part 2 Pipe Joint Body A Pipe Joint 3 Pipe End Insertion Gap B Pipe b Pipe End 4 Rubber Packing 5 Lock Member

Claims (1)

[Claims] 1. A synthetic resin molded body having a tubular core portion is fixedly provided in a pipe joint body, and a gap for inserting a pipe end portion is formed between an outer surface of the tubular core portion and an inner surface of the pipe joint body. The pipe end is inserted into the gap for inserting the pipe end of the pipe joint, a rubber packing is mounted between the outer surface of the tubular core portion and the inner surface of the pipe end, and a locking member is provided between the pipe joint body and the outer surface of the pipe. A structure of a connecting portion between a pipe and a pipe joint, which is characterized in that the pipe and the pipe joint are bonded together.