JP6130746B2 - Coupling type fitting - Google Patents

Description

  The present invention relates to a coupling type pipe joint for connecting a pipe for flowing a fluid such as city gas.

  Conventionally, as pipe joints for connecting piping for transporting fuel gas such as city gas, as shown in Patent Document 1 (Japanese Patent Laid-Open No. 59-50289) and Patent Document 2 (Japanese Patent Laid-Open No. 2010-249258), A fitting main body, a push ring screwed into the pipe fitting main body, and a packing, a retainer, a pipe retaining member, and a fireproof and airtight filler provided in a space formed between the pipe fitting main body, the push ring and the outer surface of the pipe. Mechanical connection type (mechanical connection type) pipe joints are in practical use. According to this pipe joint, since a packing, a retainer, a pipe retaining member, and a fireproof and airtight filler are provided in a space formed between the pipe joint main body, the push ring, and the outer surface of the pipe, a fire occurs. Even if the packing is burned out, the space formed between the pipe, push ring, and joint body is filled with fireproof and airtight filler, so gas does not leak from the piping, and secondary due to gas leakage. Disaster can be prevented.

JP 59-50289 A JP 2010-249258 A

However, the above-mentioned mechanical connection type pipe joint has a structure that gives the packing surface pressure necessary for the seal by screwing the screws formed on the joint body and the press ring respectively, so that the outer diameter of the pipe increases. The joint body and the press ring must be tightened with a large tightening torque, and it is only practical for pipes having a relatively small outer diameter up to a nominal diameter of 80A. If it is a mechanical connection type pipe joint that connects pipes of 100A or more, the connection part of the presser wheel and the joint body must have a screw connection structure instead of a screw connection structure due to insufficient tightening torque. In this case, the flange portion must be tightened with a plurality of bolts and a plurality of nuts, and there is a problem that workability is poor. For this reason, in the case of connection of large diameter pipes, in fact, it is often connected using a welded joint, but the welded joint also has problems such as poor workability and increased connection costs.
Therefore, the present invention has been made in view of the above circumstances, and even when exposed to a high temperature such as a fire, the fluid in the pipe does not leak to the outside, and the pipe has a relatively large diameter. Even so, an object of the present invention is to provide a pipe joint capable of easily performing pipe connection.

In order to achieve the above object, a coupling-type pipe joint of the present invention includes:
A casing mounted on the outer periphery of the end of a pair of pipes connected to face each other; a seal member mounted inside the casing and hermetically sealing the outer periphery of the pair of pipes; A coupling member having a diameter reduced along the pipe, and a high-temperature-expandable seal member that is volume-expanded at high temperature and is filled in the casing; And an inner cylinder inserted over the inside of both the tubes.

  According to this coupling type pipe joint, a casing having a sealing member and a retaining member is mounted on the outer periphery of the end of the pair of pipes, and the casing is reduced in diameter along the outer periphery of the pipe by tightening the fastening member. Let the tube be connected. Thereby, even if it is a case where a pipe | tube with a large outer diameter is connected, a connection operation | work can be performed easily. Further, according to this coupling type pipe joint, since the high temperature expansible seal member is provided inside the casing, when the joint is exposed to a high temperature due to a fire or the like, the high temperature expansible seal member is volume-expanded by heat. The casing is filled. At this time, since this coupling type pipe joint includes an inner cylinder inserted across both pipes in the opposite pipe, the volume-expanded high-temperature-expandable sealing member does not flow into the pipe, I can be dammed up. As a result, the volume-expanded high-temperature-expandable seal member is filled so that the space inside the casing and between the inner surface of the tube and the inner cylinder is tightly filled without causing density density, and fluid leaks from the joint. Is reliably prevented.

In the coupling type pipe joint of the present invention,
The inner cylinder is fitted with an annular member that can be inserted into the tube and restricts inflow of the high-temperature expansion seal member into the tube when the high-temperature expansion seal member expands. preferable. The annular member externally fitted to the inner cylinder fills the gap between the inner cylinder and the inner surface of the pipe by being fitted between the inner cylinder and the inner surface of the pipe. The flow into the pipe is more reliably regulated as compared with the case where the inner cylinder alone is used to prevent the fluid from leaking out from the joint.

In the coupling type pipe joint of the present invention,
The inner cylinder may be a cylindrical body that can be inserted from an end of the pipe.

In the coupling type pipe joint of the present invention,
The inner cylinder may be a metal plate that is rounded into an elastically expandable / contractible cylinder and can be inserted from the end of the pipe.

In the coupling type pipe joint of the present invention,
The high-temperature-expandable seal member may be a cylindrical body that is externally fitted to the inner cylinder and is inserted into the tube together with the inner cylinder.

In the coupling type pipe joint of the present invention,
It is preferable that the high-temperature-expandable seal member has a positioning protrusion larger than the inner diameter of the tube at the center.

In the coupling type pipe joint of the present invention,
It is preferable that the inner cylinder has a large-diameter portion larger than the inner diameter dimension of the tube at the center.

In the coupling type pipe joint of the present invention,
The high-temperature-expandable seal member may be provided on the outer periphery of the tube.

  According to the coupling type pipe joint of the present invention, since the casing is attached to the outer periphery of the end of the pipe and can be connected to the pipe by a simple operation of tightening with a fastening member, the pipe can be easily connected even to a large-diameter pipe. Can be connected. The coupling-type pipe joint of the present invention includes a high-temperature-expandable seal member that is volume-expanded at a high temperature and is filled in the casing, and an inner cylinder that is inserted over both opposing pipes. Therefore, even when the joint is exposed to a high temperature such as a fire and the seal member is burned out, it is possible to fill the casing with the high-temperature expandable seal member that has undergone volume expansion due to heat without flowing into the pipe. it can. Thus, according to the coupling type pipe joint of the present invention, it is possible to connect easily even when connecting a large-diameter pipe, and even if the joint is exposed to high temperature due to a fire or the like, the fluid in the pipe Can have good fire resistance that does not leak to the outside of the joint.

It is a perspective view which shows the use condition of the coupling type pipe joint which concerns on this invention. It is a longitudinal cross-sectional view of the coupling type pipe joint which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the construction procedure of the coupling type pipe joint which concerns on the 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the coupling type joint which concerns on 2nd Embodiment of this invention. It is a perspective view which shows the other form of an inner cylinder.

Hereinafter, a coupling type pipe joint according to an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the coupling-type pipe joint 1 according to the first embodiment of the present invention connects two opposing ends of two pipes P that allow fluid such as gas to flow. A casing (joint body) 2 mounted on the outer peripheral end of the pipe P, and a fastening means including a bolt 3 and a nut 4 for reducing the diameter of the casing 2 along the outer periphery of the pipe P are provided. In the present embodiment, the nut 4 is a rod-shaped special nut in which a female screw is formed that penetrates a round bar in the lateral direction and is screwed into the bolt 3. The casing 2 is formed of a metal plate having a U-shaped cross section and is formed in a C shape along the outer periphery of the pipe P. Similarly, the casing 2 fills the open portion of the casing body member 21. It consists of a slide plate 22 whose cross section is bent into a U-shape. The casing 2 is an annular body having a U-shaped cross section with the casing body 21 and the slide plate 22, and is surrounded by the outer surface of the pipe P and the inner surface of the casing 2 on the entire outer periphery of the pipe P. An annular space is formed.

  As shown in FIG. 2, the casing 2 has a cylindrical seal member 5 formed with a lip portion 51 that seals the outer surface of the pipe P, and is pressed against the outer periphery of the pipe P so that the pipe is pulled out. A retaining member 6 to be prevented is accommodated. The seal member 5 can be made of nitrile butadiene rubber (NBR) having excellent sealing properties and corrosion resistance.

Further, on the inner diameter side of the two opposing pipes P, there is a cylindrical high-temperature-expandable seal member 8 that is externally fitted to the inner cylinder 7 that is a stainless steel cylindrical body and can be inserted into the pipe P. Has been inserted. An annular member 9 is externally fitted on the outer periphery of the inner cylinder 7 on the outer sides of both ends of the high-temperature-expandable seal member 8. For example, two coil springs can be used for the annular member 9 as shown in FIG.
As the material of the high-temperature-expandable seal member 8, nitrile butadiene rubber containing expanded graphite that expands when exposed to a high temperature such as a fire can be used. The high-temperature-expandable seal member 8 may be formed into a cylindrical body by molding, or may be formed into a cylindrical body by rolling a sheet material.

  A procedure for connecting the two pipes P by the coupling-type pipe joint 1 will be described with reference to FIG. First, as shown in FIG. 3 (a), a sealing member 5 and a retaining member 6 are attached to the casing 2, and a coupling type pipe joint in a state before tightening is prepared so that the pipe P can be inserted. The pipe P is inserted from one end of the ring-shaped pipe joint 1 to a predetermined position.

  Next, as shown in FIG. 3 (b), the high-temperature expansibility that is externally fitted to the inner cylinder 7 while being sandwiched and restrained by two annular members 9 on the inner diameter side of the end of the inserted pipe P The seal member 8 is inserted. At this time, the high-temperature-expandable seal member 8 is inserted until the positioning protrusion 81 provided so as to protrude from the center portion of the high-temperature expandable seal member 8 hits the end of the pipe P. Since the positioning projection 81 is formed to be larger than the inner diameter dimension of the tube P, the end of the tube P is abutted against the positioning projection 81, so that the high-temperature expandable seal member 8 having a desired length is reliably inserted. . Instead of the positioning projection 81 in the present embodiment, a large diameter portion larger than the inner diameter of the tube is provided on the inner cylinder that externally fits the high-temperature-expandable seal member, and the end of the tube is abutted against the large diameter portion. May be performed.

  Next, as shown in FIG. 3C, the pipe P is inserted from the other end of the coupling type pipe joint 1. At this time, as in the case of the other pipe P, the high-temperature-expandable seal member 8 is inserted on the inner diameter side of the end of the pipe P.

  Next, by tightening the bolt 3 and the nut 4 to reduce the diameter of the casing 2 along the pipe P, the seal member 5 is brought into close contact with the outer surface of the pipe P, and the retaining member 6 is firmly pressed against the outer surface of the pipe P. To connect the pipe P.

  Next, the operation when exposed to a high temperature such as a fire will be described. In a pipe joint that does not have a high-temperature-expandable seal member, when the joint is exposed to a high temperature such as a fire, the seal member 5 is burned out and the function of sealing the internal fluid is lost. However, the coupling type according to the present embodiment According to the pipe joint 1, as shown in FIG. 2, since the high-temperature expandable seal member 8 is provided between the inner surface of the pipe P and the inner cylinder 7, the high-temperature expandable seal member 8 expands in the event of a fire. Thus, the space in the gap between the pipe P and the inner cylinder 7 or the inside of the casing is prevented, and the fluid inside the pipe is prevented from leaking out of the joint. Furthermore, since both ends of the high-temperature expandable seal member 8 are restrained by the annular member 9, the high-temperature expandable seal member 8 expanded during a fire is prevented from flowing into the pipe P. Therefore, the high-temperature-expandable sealing member is filled in the gap between the pipe P and the inner cylinder 7 and the inside of the casing 2 so as to be tightly packed without causing any density to be ensured, and a good sealing performance is ensured. Further, by making the outer diameter dimension of the annular member 9 substantially the same as the inner diameter dimension of the pipe P, the inner cylinder 7 is prevented from being biased inside the pipe P, and high temperature expansion is caused around the inner cylinder 7. A space in which the conductive sealing member can be uniformly expanded is secured. The annular member 9 is not necessarily required and can be selected as necessary.

(Second Embodiment)
As shown in FIG. 4, the coupling type pipe joint 1 </ b> A according to the second embodiment of the present invention has a high-temperature-expandable seal member 8 </ b> A disposed on the outer periphery of the pipe P, and an annular shape inside the pipe P. 2 is the same as the coupling joint 1 shown in FIG. 2 except that the inner cylinder 7 into which only the member 9 is fitted is inserted, and the same portions are denoted by the same reference numerals and the description thereof is omitted. Similarly to the coupling-type pipe joint according to the first embodiment, in this coupling-type pipe joint, the high-temperature-expandable seal member does not cause density in the pipe when expanded at a high temperature during a fire. The gap between P and the inner cylinder 7 and the inside of the casing 2 are filled, and good sealing performance is ensured.

  In the first and second embodiments, the inner cylinder 7 is a cylindrical body that can be inserted from the end of the pipe P. However, as shown in FIG. It can also be set as the cylindrical body formed by rounding into the cylinder shape expandable / shrinkable. According to this inner cylinder 7A, when the high-temperature expandable seal member expands, the inner cylinder 7A is reduced in diameter inside the pipe P by the expansion force of the high-temperature expandable seal member, and the inner surface of the pipe P and the inner cylinder 7A Since the space in which the high-temperature expandable sealing member expands is reliably formed over the entire circumference between the outer surface and the outer surface of the cover, the high-temperature expandable member expands uniformly over the entire periphery without being biased, and good sealing performance is obtained.

P: Pipe 1, 1A: Coupling type pipe joint 2: Casing 21: Casing main body, 22: Slide plate 3: Bolt 4: Nut 5: Seal member 6: Retaining member 7, 7A: Inner cylinder 8: High temperature expansibility Seal member 9: annular member

Claims (8)

A casing mounted on the outer periphery of the ends of a pair of pipes connected to face each other;
A seal member that is mounted inside the casing and seals the outer periphery of the pair of pipes;
A fastening member for reducing the diameter of the casing along the pipe;
A coupling type pipe joint comprising:
A high-temperature-expandable sealing member that is volume-expanded at a high temperature and is filled into the casing;
An inner cylinder that is inserted across both of the opposing pipes when connecting the pipes;
Coupling type pipe joint characterized by comprising The inner cylinder is fitted with an annular member that can be inserted into the pipe and regulates the flow of the high-temperature expansion seal member into the pipe when the high-temperature expandable seal member expands. The coupling type pipe joint according to claim 1, wherein The coupling-type pipe joint according to claim 1 or 2, wherein the inner cylinder is a cylindrical body that can be inserted from an end of the pipe. 3. The coupling type according to claim 1, wherein the inner cylinder is made of a metal plate that is rounded into an elastically expandable / contractible cylinder and that can be inserted from an end of the pipe. Pipe fittings. The said high-temperature-expandable sealing member is a cylindrical body externally fitted to the inner cylinder and inserted into the tube together with the inner cylinder. The coupling-type pipe joint according to item. 6. The coupling-type pipe joint according to claim 5, wherein the high-temperature-expandable seal member includes a positioning protrusion larger than an inner diameter dimension of the pipe at a central portion thereof. The coupling-type pipe joint according to claim 5, wherein the inner cylinder includes a large-diameter portion larger than an inner diameter dimension of the tube at a central portion thereof. The coupling-type pipe joint according to any one of claims 1 to 4, wherein the high-temperature-expandable seal member is provided on an outer peripheral portion of the pipe.

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