JPH1144385A - Attachment corrosion-proof pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make packing and a core hard to be damaged by making its axes coincide with each other so that a pipe can be easily inserted. SOLUTION: On an end part inside surface of a pipe joint main body 1, an expansible/contractible slipping-out preventive ring 3 to fasten/fix a pipe and a pipe joint by biting into a pipe end part outside surface, is housed and arranged in a recessed groove 11, and on its inmost side, annular packing 4 to seal a part between a pipe outside surface and the pipe joint by being brought into pressure contact with the pipe end part outside surface, is housed and arranged in a recessed groove 12, and an O ring (a core pressure contact seal part) 5 to seal a part between a pipe inside surface and a cylindrical core 21 by being brought into pressure contact with an inside surface of a pipe P in an end part side outward position more than the annular packing 4, is also arranged on an outside surface of the cylindrical core 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin-lined steel pipe having a resin-lining layer at least on an inner surface thereof (hereinafter referred to as a "resin-lined steel pipe").
It may be called a lining steel pipe or simply a pipe. The present invention relates to a plug-in type anticorrosion pipe joint which can be connected simply by inserting a pipe without corroding the pipe end face and cutting the pipe end.

[0002]

2. Description of the Related Art Conventionally, a resin-lined steel pipe and a pipe end anticorrosion pipe joint are often used as a countermeasure against red water in a water supply pipe or a hot water pipe. However, since these were screw-in types or mechanical types using nuts, etc.,
Threading and assembling of parts were required, and the workability was poor. Therefore, a plug-in type pipe end anticorrosion joint that can be connected simply by inserting a pipe has been proposed.

[0003] For example, there is a plug-in type anticorrosion pipe joint disclosed in Japanese Patent Application Laid-Open No. Hei 4-203688. As shown in FIG. 4, a concave groove 51 having a tapered inner surface 51a is formed on an inner peripheral surface of an end portion of the pipe joint body 50, and a retaining ring 52 which can be expanded and contracted in the radial direction is accommodated therein, as shown in FIG. Further, a concave groove 53 is formed on the inner side, and an annular packing 54 which presses against the outer surface of the tube is accommodated therein. Further, a tube end anticorrosion core 56 provided with an annular packing 55 for sealing the inner surface of the tube end in a watertight manner is provided on the inner side of the concave groove 53. Therefore, just by inserting the lining steel pipe P, the annular packing 55 of the cylindrical core is pressed against the inner peripheral surface of the pipe, and the annular packing 54 is pressed against the outer peripheral surface of the pipe to form a watertight seal, thereby preventing the pipe end from being corroded. You. Thereafter, when the pipe is pulled in the pulling direction, the retaining split ring 52 moves along the tapered inner surface 51a and is engaged with the pipe outer surface.

[0004]

The plug-in type anticorrosion pipe joint 50 has a cylindrical core (hereinafter, may be simply referred to as a core) 56. The core has a concave groove 53 at its tip. And packing 54 are provided inside. That is, since the pipe end insertion portion is formed only on the back side of the joint main body, there is an advantage that the packing 54 and the core 56 do not interfere with each other in position and the assembling property is good.
However, since the cylindrical core is located on the back side, there are the following problems.

(1) In a bayonet joint, it is necessary to provide a slight gap between the inside diameter of the joint body and the outside diameter of the pipe to absorb the respective tolerances and allow easy insertion. . However, on the contrary, even if the force is relatively low, the axis of the pipe and the joint is displaced, and a problem is apt to occur that the pipe and the joint are inclined. The displacement amount due to the inclination of the pipe viewed from the joint main body in FIG. 4 is maximum at the point a at the inner end of the pipe end insertion portion (that is, at the pipe end) and at the point b at the end face contact portion of the joint main body. Therefore, when the core is located at the inner side of the packing 54, the packing 55 on the inner surface seal side is located closer to the inner end of the pipe end insertion portion, and is easily affected by a large displacement. On the other hand, the thickness of the seal part is as small as possible because the pressure loss of the internal fluid must be reduced as much as possible on the pipe inner seal part.
In this case, the diameter of the packing 55 is made smaller. For this reason, if there is a small absorption force against the displacement in the radial direction and there is a large displacement, there is a high risk that the sealing performance is impaired and red water is generated.
Further, in order to reduce the displacement, the joint body and the core may both be lengthened to increase the insertion length. However, this increases the overall length of the joint, which is not practical especially for elbows and cheeses.

(2) In the process of inserting the pipe, the end of the pipe is first pressed against the packing 54 on the main body side, and then pressed against the packing 55 on the core side. However, in the case of the plug-in type, unlike the screw-in type, there is no guarantee that the pipe will be inserted so as to coincide with the axis of the joint. Therefore, when the pipe is inserted while being inclined, the pipe end first collides with the annular packing 54, and this packing 54 is removed. A force acts such as to drop out of the concave groove 53. Further, the core 56 and the packing 55 may be hit and damaged. Particularly in connection work in a narrow space or the like surrounded by a wall, the above-described situation is likely to occur because not only is it difficult to insert but also the core is located at a position that is difficult to see on the back side.

(3) The plug-in type anticorrosion pipe joint 50 described above
In the case of (1), the position is shifted so that the cylindrical core 56 and the packing 54 do not interfere with each other in the length direction, so that the overall length of the joint is long.

An object of the present invention is to provide a plug-in type anticorrosion pipe joint in which the joint is made compact, the pipe is easily inserted, and the packing and the core are made hard to be damaged by making the pipe compact. Is what you do.

[0009]

According to the present invention, an inner resin coating layer is formed on an inner peripheral surface of a pipe joint body, and a tubular core extending toward an end is provided. In a plug-in type anticorrosion pipe joint having a built-in core in which a pipe end insertion portion is formed between a coating layer and a cylindrical core, the pipe and the pipe are cut into the inner surface of the end of the pipe joint body at the outer surface of the pipe end. An expandable / retractable retaining ring for fastening and fixing the joint is provided, and an annular packing is provided on the inner side of the ring to press against the outer surface of the pipe end to seal between the outer surface of the pipe and the pipe joint. It is a plug-in type anticorrosion pipe joint provided with a core press-welding seal portion which presses against the inner surface of the pipe at an outer position on the outer side closer to the end of the joint than the annular packing to seal between the inner surface of the pipe and the cylindrical core. . Here, the above-mentioned retaining ring forms a first groove and is accommodated and provided therein, and the annular packing is formed with a second groove and is accommodated therein.

[0010] Further, the annular packing is formed with an enlarged diameter step on the inner surface on the end side of the second concave groove, and the annular packing is formed with a thick step fitted to the enlarged diameter step.
It is desirable to form a lip-shaped seal portion on the inner surface side.
Further, it is desirable that the position of the core pressure seal portion of the cylindrical core is located near the center of the entire length of the tube inserted between the annular packing and the retaining ring. The core pressure seal portion is an annular protrusion integrally formed with the core or an annular elastic packing made of rubber or polymer elastomer. The outer surface of the cylindrical core other than the core pressure seal portion has the same diameter as or slightly smaller than the inner surface of the tube. It is desirable to be formed in.

As described above, the amount of displacement due to the inclination of the pipe becomes maximum at the deep end of the pipe end insertion portion and at the abutting portion of the joint end face, and conversely, the amount of displacement decreases toward the middle between them and becomes zero at the center. According to the plug-in type anticorrosion pipe joint described above in this regard,
The cylindrical core extends toward the end of the joint main body, and is provided with a core pressure-sealing seal portion at least at a position outside the annular packing. Preferably, a substantially central portion of the entire tube insertion length between the annular packing and the retaining ring is provided. It is located near.
As a result, the seal portion on the inner surface of the tube is provided at a position where the displacement amount is the least and is not affected by the displacement amount, so that the sealing performance is not reduced and no red water is generated. Here, it is more advantageous for displacement if the annular packing on the outer surface of the tube is moved as close to the center of the tube insertion length as possible. The compression resistance between the packing and the core pressure seal portion overlaps and is amplified, making insertion work difficult. For this reason, the position of the annular packing is located deeper than the core pressure seal portion so that they do not interfere with each other. Therefore, it is easily affected by displacement,
In this regard, the lip structure has a sufficient absorption allowance (compression allowance) as compared with the pressure contact seal portion on the inner diameter side, so that there is no influence on the sealability.

Further, since the tubular core is located close to the insertion opening of the joint body and is easy to see from the outside, it is easy to insert the pipe, and the inserted pipe is first guided by the core press-sealing portion to guide the inner surface of the pipe. The axis of the pipe and the joint body coincide. Then, the inner surface side of the pipe is first watertightly sealed by the core pressure sealing portion, and then the outer surface side is watertightly sealed by the annular packing. Further, an enlarged diameter stepped portion was provided on the inner surface on the end side of the second groove, and one of the annular packings was made thick so as to fit into this stepped portion. Thereby, even if a biased force is applied to the annular packing when the pipe is inserted, the resistance is strong and the packing can be prevented from falling off.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a half cross-sectional view of a plug-in type anticorrosive pipe joint F1 showing one embodiment of the present invention. The figure has a left-right symmetric structure, the left side of which shows before pipe connection and the right side shows after pipe connection. Here, the pipe may be a poly-powder-lined steel pipe in which a polyethylene powder resin P2 is lined on the inner surface of a steel pipe portion P1 or a PVC-lined steel pipe in which a vinyl chloride resin P2 thicker than the poly-powder resin is lined on the inner surface. Collectively referred to as lining steel pipe P.

In FIG. 1, reference numeral 1 denotes a metal (for example, malleable cast iron) pipe joint main body, and a first concave groove for accommodating a retaining ring 3 from the main body end 10 side as shown in FIG. 1
1 and a second concave groove 12 for accommodating the annular packing 4 for sealing the outer surface of the tube in a watertight manner, and a convex portion 13 is provided at a central portion. However, this step may be a concave portion. Although the joint of the present embodiment shows a socket, it may be an elbow, a cheese, or a pipe joint provided with a screw connection portion or an electric fusion connection portion on one side.

An inner resin coating layer 20 of a water-resistant resin (for example, hard vinyl chloride, polybutene, cross-linked polyethylene, etc.) is formed on the inner surface of the central portion of the joint body 1, and at the same time, a cylindrical shape extending toward the end portion is formed. The core 21 is integrally formed. By these, the inner resin coating layer 20 and the cylindrical core 21 are formed.
And a pipe end insertion portion 24 for accommodating the end of the lining steel pipe P. Here, the length of the cylindrical core 21 extends at least outside the annular packing 4 having the second concave groove, and the core pressure seal portion is provided here. In this example, a groove 23 for mounting an O-ring shaped annular packing 5 (hereinafter, referred to as an O-ring 5) is provided at a substantially intermediate position between the packing 4 and the retaining ring 3. The outer diameter surface 22 of the core 21 excluding the concave groove 23 is slightly smaller in diameter than the inner surface of the lining steel pipe P, so that a gap is formed between them to facilitate the insertion of the pipe. The size of the gap is about 0.7 mm in the case of a poly powder lining steel pipe, and about 0.2 mm in the case of a PVC lining steel pipe.

The annular packing 4 and the O-ring 5 are made of water-resistant rubber (eg, EPDM, SBR, etc.), and the annular packing 4 is mounted in the second groove 12 in advance. In the present example, the enlarged diameter step portion 15 is formed on the inner surface on the end portion side of the concave groove 12, while the outer peripheral surface of the annular packing 4 is also formed in the enlarged diameter step portion 1.
5 is formed in a thick step portion 40 which fits into the groove 5. The uneven portion is fitted, the packing is compressed, and fixed in the groove. With such a configuration, even if a biased force or a shocking force is applied to the packing 4 at the time of inserting the pipe,
The packing 4 can be prevented from dropping out of the concave groove 12 due to the effect of high resistance and high rigidity. On the other hand, a lip-shaped seal portion is provided on the inner surface side. Here, the first lip 41 and the second lip 42 are formed to improve the sealing property. Note that one or three or more lips may be provided. In other words, by using a lip seal, even if the pipe is inclined and the outer surface is displaced in a direction in which the outer surface is separated, the lip portion can follow and seal, and when the pipe is inserted, the outer ring surface is scratched by the retaining ring 3. Even if it can be sealed. Further, if a plurality of lip seal structures are used, higher sealing performance can be obtained by a labyrinth effect.

The retaining ring 3 is obtained by cutting off a part of a ring made of a hard metal so as to have a spring property, and has a substantially triangular cross section. I have. Therefore, when the pipe is pushed in, the diameter is increased by the force to allow passage of the pipe, and then the pipe is reduced in diameter and fitted into the annular groove P3 of the pipe, and one side of the pipe bites into the pipe and is locked. .

Next, connection work between the plug-in type anticorrosive pipe joint F1 and the lining steel pipe P will be described. First, prior to the connection work, in this example, a circular grooved groove is formed by a grooving tool at a predetermined position of the lining steel pipe P, that is, at a position where the retaining ring 3 comes into contact when the pipe is normally inserted to the inner part of the pipe insertion portion 24. The groove P3 is processed. At this time, a shallow groove P4 or a knurl is formed at a position outside the groove P3 and close to the joint end face 10 at the same time. This serves as an indicator that allows the operator and a third party to visually check whether or not the pipe has been inserted correctly. Is easier to confirm.

Thereafter, when the pipe P is inserted into the joint body 1,
The end of the pipe can be pushed forward by first opening the retaining ring 3 and expanding the diameter. However, the end of the pipe is immediately pressed against the O-ring packing 5 of the cylindrical core 21 and the inner surface of the pipe is guided by this, and the axis of the pipe and the joint body is The cores match. After that, the inner peripheral surface 22 of the cylindrical core 21
Since the diameter of the pipe is slightly smaller than the inner surface of the pipe, a force for pushing the pipe is not so required, and the pipe can be pushed relatively smoothly. When the pipe P is inserted into the inner part of the pipe insertion portion 24, the inner surface of the pipe is water-tightly sealed by the O-ring 5, the outer surface of the pipe is water-tightly sealed by the annular packing 4, and the end of the pipe is completely corrosion-proof sealed. . On the other hand, the tip of the core is a concave groove P3.
As a result, excessive insertion is suppressed, and at the same time, the retaining ring 3 is fitted into the concave groove P3 to prevent the tube from falling off. At this time, the operator can know that the lock has been achieved by touching the hand, and at the same time, since the indicator groove P4 is located on the end face 10 of the joint main body, it is confirmed that the connection is normally performed even after piping. (Plumbing supervisor) can also check. Thereafter, for example, when a pulling force is applied to the pipe, the retaining ring 3 is further engaged and fixed. The position of the O-ring 5 is located near the center of the entire length L of the tube inserted between the annular packing 4 and the retaining ring 3. Therefore, even if an external force is applied and the pipe is tilted and the pipe is received by the pipe end insertion part deep end a and the joint end face contact part b, the displacement amount at the seal part position is relatively small and the O-ring 5 There is no decrease in sealing performance. Further, the annular packing 4 can sufficiently follow the displacement by the function of the lip-shaped seal portion, and the sealing property does not decrease.

Next, FIG. 2 is a half sectional view of a plug-in type anticorrosive pipe joint F2 showing another embodiment of the present invention. The left side shows a state before the pipe connection, and the right side shows a state after the pipe connection. In the present embodiment, the first concave groove 61 is formed as a tapered inner surface 62 whose diameter is reduced toward the end side, in which the retaining ring 8 having an arcuate outer surface and having a blade on the inner surface is accommodated. Similarly, the retaining ring 8 is also capable of expanding and contracting by cutting off a part of the ring, and its diameter is reduced along the tapered surface so that its blade bites into the outer surface of the tube and is prevented from falling off.
The annular packing 9 has a lip-shaped seal portion 91 on the inner diameter side, and further has a protruding portion 93 which extends to the concave groove 61 at the rear end and presses the retaining ring 8 against the tapered inner surface side.
Are provided integrally. The inner resin coating layer 7
0 and the cylindrical core 71 are connected to the pipe end insertion portion 7 in the same manner as in the above embodiment.
4 extending toward the end of the joint body. An annular projection 73 is formed between the retaining ring 8 and the annular packing 9 as a core pressure seal portion. The protrusion 73 is also provided with the annular packing 9 and the retaining ring 8.
Is located near the center of the entire tube insertion length. still,
The protrusions may be provided over a plurality of lines at intervals. In this example, a concave groove is not formed in the pipe P at the time of the pipe connection work as in the above embodiment, but a knurl P5 for confirming insertion is provided as shown in the figure. Subsequent pipe insertion work and effects are the same as those in the above-described embodiment, and a description thereof will be omitted.

In each of the above-described embodiments, the first groove for accommodating the retaining ring and the second groove for accommodating the annular packing are separately provided. However, the present invention is not limited to this. For example, without providing individual concave grooves, using a retainer that supports the annular packing and a stopper ring that stops the retaining ring, these are mounted in the joint body in the order of the annular packing, the retainer, the retaining ring, and the stopper ring, and mechanically The present invention can also be implemented as a plug-in type pipe joint having a connecting portion.

By the way, the cylindrical cores 21 and 71 used in the above-described embodiment are provided with the concave groove 23 or the projection 73 integrally. Therefore, when the inner resin coating layer 20 or 70 is to be integrally injection-molded with the inner resin coating layer 70 or 70, the concave grooves and projections become so-called undercut portions, and molding is difficult. Therefore, one of these forming means will be described with reference to FIG. First, in this example, the cylindrical core 2 is prepared by injection molding separately. This can be molded without any problem because it is a single core regardless of whether it has a concave groove or a projection.
When the inner resin coating layer of the joint body 1 is injection-molded, the above-described separately formed cylindrical cores 2 are attached to the outer circumferences of the tip ends of the molding mandrels MR and ML, respectively. Attach the annular packing P. After that, the molding sleeves SR and SL and the cored mandrels MR and ML are inserted from both ends of the joint main body, and a cavity C (opening portion in the drawing) corresponding to the resin coating layer is formed on the inner surface of the central portion. Thereafter, a molten resin is injection-molded into the cavity C from the gate G via a resin molding runner R provided inside at least one mandrel to form an inner resin coating layer. At this time, since the distal end 2a of the cylindrical core faces the cavity C, the distal end 2a comes into contact with the molten resin to be melted and can be fixed integrally with the inner resin coating layer.

As another method, after injection molding the inner resin coating layer, a separately molded cylindrical core is fused to the end of the inner resin coating layer by ultrasonic vibration. Similarly, a separately molded core is thermally fused to the end of the inner resin coating layer by rotational friction. Further, heat fusion is performed by a heating plate. Alternatively, a method may be considered in which the inner resin coating layer and a cylindrical core having no grooves or protrusions are first injection-molded, and then the leading end portion of the core is heated and compressed by a heating jig to form the groove portion later. Can be

[0024]

As described above, according to the plug-in type anticorrosive pipe joint of the present invention, the pipe can be easily inserted, and the pipe and the pipe joint can be correctly inserted at an early stage by aligning the axes of the pipe and the pipe joint. Therefore, the inner side and the outer side can be securely watertightly sealed without damaging the sealing portion such as the packing. In addition, even if the pipe is inclined, the plug-type anticorrosion pipe joint has no deterioration in the sealing performance of the core pressure-sealing seal portion and the annular packing provided on the core and does not generate red water.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a plug-in type anticorrosion pipe joint showing one embodiment of the present invention. The left side shows the state before the tube insertion, and the right side shows the state after the tube insertion.

FIG. 2 is a half sectional view of a plug-in type anticorrosion pipe joint showing another embodiment of the present invention. The left side shows the state before the tube insertion, and the right side shows the state after the tube insertion.

FIG. 3 is a cross-sectional view of a molding die or the like showing an example of a method for molding a resin coating layer and a cylindrical core of a corrosion-resistant pipe joint.

FIG. 4 is a half sectional view showing an example of a conventional plug-in type anticorrosion pipe joint.

[Explanation of symbols]

F1, F2: Plug-in anticorrosion pipe fittings 1,
6: Fitting body 3, 8: Retaining ring 4,
9: Annular packing 5: O-ring (core pressure seal section) 7
3: Protrusions (core pressure seal portion) 10: End of joint body 11, 6
1: first groove 12, 64: second groove 1
3: Joint body convex part 14: Pipe end insertion part 1
5: Step of concave groove 20, 70: Inner surface resin coating layer 21, 7
1: cylindrical core 22, 72: outer surface of cylindrical core 2
3: Packing mounting groove 40: Thick step 41, 4
2: Lip-shaped seal P: Resin-lined steel pipe P
1: Steel pipe part P2: Resin lining layer P
3: Annular groove P4: Indicator groove P
5: Knurl eyes R: Runner
G: Gate MR, ML: Molding mandrel SR, S
L: Molded sleeve DR, DL: Outer mold
C: cavity

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Matsul Manish 2nd Daifuku, Kuwana-shi, Mie Hitachi Metals, Ltd. Kuwana Plant (72) Inventor Tsutomu Somai 75 Nojiri, Ritto-cho, Kurita-gun, Shiga 75 Sekisui Chemical Co., Ltd. (72) Inventor Masahiko Okumura 75 Nojiri, Ritto-cho, Kurita-gun, Shiga Prefecture Inside Sekisui Chemical Co., Ltd.

Claims (5)

[Claims] An inner resin coating layer is formed on an inner peripheral surface of a pipe joint body, and a tubular core extending toward an end is provided. The joint body is connected to the inner resin coating layer and the tubular core. In a plug-in type anticorrosion pipe joint with a built-in core in which a pipe end insertion part is formed, an expandable / contractible type in which the pipe and the pipe joint are fastened and fixed to the inner surface of the end of the pipe joint body by biting into the outer surface of the pipe end. An annular gasket is provided on the inner side of the tubular core, and an annular packing is provided on the inner side of the ring to seal between the outer surface of the tube and the pipe joint. A plug-in type anticorrosion pipe joint comprising a core press-welding seal portion which presses against an inner surface of a pipe at an outer position on a joint end side to seal between the inner surface of the pipe and a cylindrical core. 2. An inner resin coating layer is formed on an inner peripheral surface of a pipe joint main body, and a cylindrical core extending toward an end is provided. The joint main body is connected to the inner resin coating layer and the cylindrical core. In a plug-in type anticorrosion pipe joint with a built-in core in which a pipe end insertion part is formed, an expandable / contractible type in which the pipe and the pipe joint are fastened and fixed to the inner surface of the end of the pipe joint body by biting into the outer surface of the pipe end. An annular gasket is provided in the first groove so as to be housed in the first groove, and an annular packing for pressing the outer surface of the pipe end to seal between the outer surface of the pipe and the pipe joint is provided in the second groove. And a core press contacting the outer surface of the cylindrical core at an outer position closer to the joint end than the annular packing to press the inner surface of the tube to seal between the inner surface of the tube and the cylindrical core. A plug-in type anticorrosion pipe joint characterized by having a seal portion. 3. An enlarged diameter step portion is formed on the inner surface of the joint end portion side of the second concave groove, and the annular packing forms a thick step portion to be fitted to the enlarged diameter step portion. The plug-in type anticorrosion pipe joint according to claim 2, wherein a lip-shaped seal portion is formed. 4. The seal according to claim 1, wherein the core pressure seal portion is located near the center of the entire tube insertion length between the annular packing and the retaining ring. Plug-in anticorrosion pipe fittings. 5. The core pressure contact seal portion is an annular protrusion or an annular elastic packing, and the outer surface of the cylindrical core other than the core pressure contact seal portion is formed to have the same diameter as or slightly smaller than the inner surface of the tube. The plug-in type anticorrosion pipe joint according to any one of claims 1 to 4.