JP2009243601A - Extensible union joint and liquid transfer piping system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To heighten convenience of a pipe connection operation and a maintenance operation with a union joint, and functional reliability of the union joint. <P>SOLUTION: This union joint comprises a union flange 2 connected to one piping member 1, a union flange 3 connected to a slide member 8 which is the other pipe, and a union nut 4 connecting the members 2 and 3. A part of the slide member 8 is inserted in an inner diameter part of a union screw 3 via a self-sealing type packing 7. An insertion amount can be adjusted by a relative axial slide to the union screw. A locking bolt 6 is provided to the union screw 3. A tapered part T whose diameter gets smaller from a side inserted in the union screw toward its opposite side is provided at an outer diameter part of the slide member 8, and a tip of the locking bolt 6 contacts the tapered part by fastening. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel expandable union joint used in, for example, a nuclear power plant or a general plant having piping equipment, and a fluid transfer piping system using the same.

  Conventionally, as this kind of union joint, a union joint comprising a union screw attached to one pipe, a union collar attached to the other pipe, and a union nut connecting both of them is known.

  For example, in the expandable union joint structure described in Patent Document 1 (Japanese Patent Laid-Open No. 2005-3038), when the union nut is loosened and the nut is separated from the union screw, the union screw and the union brim Is in a disconnected state. In this state, one pipe (referred to as a slide member or a sleeve) and the union screw are relatively slidable in the axial direction.

  In a state where the union nut is tightened and the union screw and the union brim are coupled, the pipes are also connected via the union joint. Between the inner diameter of the union screw and the outer diameter of the one of the pipes, a self-standing sealed packing is interposed, and the U-shaped packing of the cross section U is spread outward by the fluid pressure introduced from the pipe, Sealing is performed in close contact with the inner diameter and the outer diameter of the one pipe.

  In this prior art, when the union nut is loosened and the union screw is separated from the nut, the union screw can slide on the pipe. As a result, the self-sealing packing attached to the pipe is exposed, and there is an advantage that the packing can be replaced with the pipe installed as it is.

  The union joint is used as a joint for connecting piping systems between pipes, for example, between valves or between a valve and a filter. In addition, in the patent document 2 (Japanese Patent Application No. 2006-310939), the present applicant adjusts the pull-in amount of the pipe (slide member or sleeve) to the union screw in the same union joint, and provides the union screw after the adjustment. This pipe is fixed by tightening a lock bolt, and the pipe length between a union joint and a valve or the like is adjustable.

JP 2005-3038 A Japanese Patent Application No. 2006-310939

  In the prior art as described above, the pipe length between the union joint and the valve or the like can be adjusted to be adjustable while the installation of the pipe to be connected is left as it is. Has advantages. However, technical considerations regarding the flexibility as a joint and the ease of connection work in the case where a relative inclination occurs between the axes of the installed pipes are not disclosed.

  In addition, the fluid pressure in the pipe is connected to the other end of the pipe with an axial displacement of the pipe, with abnormal pressure applied to one end of the pipe (slide member or sleeve member) drawn into the union joint. There is a concern that it may be transmitted to devices such as valves and filters, which may cause damage to piping system devices and piping.

  Furthermore, it is desired to improve the sealing performance of the self-standing sealing type packing that seals between the union joint and the pipe.

  The present invention solves the various problems as described above and can provide an expansion joint type union joint that can improve the piping connection work and maintenance work by the union joint and the functional reliability of the union joint, and the same. It is in providing the used fluid transfer system piping.

  The present invention is basically configured as follows.

A union nut with one open and the other bag-shaped;
A union collar inserted into the bag-like side of the union nut and connected to one piping member;
A union screw that is screw-coupled to the inner diameter portion of the union nut on the open side, and whose one end can be abutted against one end of the union collar via a first packing;
A slide member that is inserted into the inner diameter portion of the union screw via a second packing and that is a piping member that can be adjusted by sliding in the axial direction relative to the union screw. Expansion joints
The union screw is provided with a lock bolt for fastening the slide member by tightening the outer diameter portion of the slide member,
The outer diameter portion of the slide member is provided with a taper portion whose diameter decreases from the side inserted into the union screw toward the opposite side so that the tip of the lock bolt comes into contact with the taper portion. It is configured.

  Preferably, the second packing is a self-supporting hermetic packing in which the packing expands outward by an internal fluid pressure and closely contacts the outer diameter of the slide member and the inner diameter of the union screw. The packing housing groove is formed by two annular protrusions provided on the outer diameter portion of the slide member, and of the annular protrusions, the annular protrusion closer to one end of the slide member on the side to be inserted into the union screw. Is provided with a curved surface section having an arc-shaped cross section at the outer peripheral edge thereof.

  Further preferably, in the annular protrusion of the annular protrusion, which is closer to one end of the slide member that is inserted into the union screw, a pressure introduction hole that guides the fluid pressure in the pipe to the self-supporting sealed packing And at least one of the notches is provided.

  According to the said structure, the reliability of the piping connection work and maintenance work by a union joint, and the functional reliability of a union joint can be improved.

Example 1
FIG. 1 is an upper half cross-sectional view and a partially enlarged cross-sectional view of the expansion / contraction union joint according to the first embodiment of the present invention. FIG. 2 is a perspective view of a tubular slide member used as one of the pipes of the expansion / contraction union joint (which may be one of pipes to be connected and may be referred to as a “sleeve”) and a self-standing sealed packing attached thereto. It is. FIG. 3 is a side view of the slide member as viewed from the direction E in FIG.

  As shown in FIG. 1, the expansion / contraction union joint of a present Example is the union collar 2 attached to the end of the piping 1 via the welding 15, and the union screw 3 attached to the end of the tubular slide member 8 used as the other piping. And a union nut 4 for connecting both the union collar 2 and the union screw 3. Here, a part of the slide member 8 is inserted into the union screw 3, and is fastened and fixed by a plurality of lock bolts 6 provided on the union screw 3. The amount of insertion of the slide member 8 into the union screw 3 can be adjusted. As a result, the length L of the sleeve 8 coming out of the union screw 3 (that is, the length L between the union screw 3 and the valve (or filter) 13) can be adjusted, so that the slide member 8 can be expanded or contracted. Sometimes referred to as a sleeve.

  The union collar 2 is a cylindrical member having a collar portion 20 at one end, and an insert portion 21 for inserting the pipe 1 is provided on the opposite side of the collar portion 20. The pipe 1 and the union collar 2 inserted in the insert portion 21 are joined by welding 15.

  The union screw 3 is a cylindrical member having a large-diameter portion 3A and a small-diameter portion 3B, and a male screw portion that is screw-coupled with the union nut 4 is formed on the outer periphery of the large-diameter portion 3A. This screw connection is indicated by 30.

  The union nut 4 is constituted by a cap nut having an opening at one end, and a female thread portion for the screw coupling 30 is cut on the inner surface on the opening side. The union nut 4 is attached to the union collar 2 so that the nut can be tightened and loosened and rotated. The union collar 2 is provided with a flange 20 to prevent the union collar 2 from coming off. ing.

  An annular groove 31 into which the squeeze packing 5 is fitted is formed on one end surface of the union screw 3, that is, the abutting surface with the union collar 2. The union screw 3 is also formed in a bag shape, and a part of the slide member 8 is inserted into its inner diameter portion by a retaining structure (described later). The inner diameter of the union screw 3 has an inner diameter portion that receives a portion of the slide member 8 on which the self-standing sealed packing 7 is mounted. The small-diameter portion 3B of the union screw 3 is provided with a screw hole 32 in the radial direction, and a lock bolt 6 for fixing the slide member 8 by fastening the outer diameter portion of the slide member 8 is attached to the screw hole 32. Yes. A plurality of lock bolts 6 are installed in the circumferential direction of the union screw 3, that is, two or more, preferably three or more, at equal intervals.

  The amount of the slide member 8 inserted into the union screw 3 can be adjusted by loosening the lock bolt 6. As described above, by adjusting the amount of insertion, the portion L of the slide member 8 coming out from the union screw 3 can be adjusted for expansion and contraction. The insertion amount of the slide member 8 can be adjusted while looking at the scale baking portion 12 provided on the outer periphery of the slide member 8.

  The amount of insertion of the slide member 8 is appropriately adjusted according to the distance between the piping system valve (or filter) 13 and the union joint, but the front end surface of the slide member 8 and the front end surface of the union collar 2 facing the slide member 8 are adjusted. Is adjusted so that a gap G can be secured in the direction of the pipe axis. The gap G is secured at the inner diameter portion of the union screw 3 and is necessary for introducing the fluid pressure of the pipe into a fluid pressure introduction hole 83 (described later) provided in the slide member 8.

  A plurality of flat portions 11 are disposed on the outer periphery of the union screw 3. When the union nut 4 and the union screw 3 are screwed together, the union nut 4 is tightened with the union screw 3 held by the flat portion 11 with a spanner.

  The slide member 8 has a male screw portion 84 (shown in FIG. 2) cut at one end of the outer periphery opposite to the portion inserted into the union screw 3, and this male screw portion 84 is a valve (or filter portion) of the piping system. It is screw-coupled to 13 female thread portions (not shown) while maintaining the sealing performance.

  The slide member 8 is formed with an annular groove 80 for attaching the packing, into which the self-supporting sealing type packing 7 is fitted and attached at one end of the side where the union screw 3 is inserted. The annular groove 80 is formed by two annular protrusions 81 and 82 formed on the outer diameter portion of the slide member 8.

  The annular protrusion 82 also functions to prevent the slide member 8 from coming off from the union screw 3 in cooperation with the inner periphery of the bag portion of the union screw 3.

  The annular protrusion 81 provided near the tip of the slide member 8 (one end on the side inserted into the union screw 3) has a curved surface shape 81a having a circular arc in cross section. Further, the annular protrusion 81 is provided with a fluid pressure introduction hole 83 for introducing the fluid pressure of the fluid flowing in the pipe into the self-supporting sealed packing 7 through the gap G described above. The fluid pressure introduction holes 83 are preferably a plurality, and are arranged at equal intervals in the circumferential direction.

  The self-standing sealing type packing 7 is made of fluorine rubber, silicone rubber or the like. The packing 7 is formed in a U-shaped cross section so that the internal pressure P1 of the internal fluid can be easily received. By receiving the internal pressure, the outer diameter surface of the packing 7 comes into close contact with the inner diameter surface of the union screw 3, and the packing 7 The inner diameter surface of the sliding member 8 comes into close contact with the outer diameter surface of the slide member 8 to provide a sealing function.

  The slide member 8 is provided with a taper T having a slight inclination angle at the outer diameter portion thereof. This taper T is secured at least in the outer diameter portion between the annular protrusion 82 and the screw portion 84, and from the annular protrusion 82 side (side to be inserted into the union screw) to the screw portion 84 side (opposite side to the insertion side). The taper ratio is set to, for example, 1/75 (diameter is reduced by 1 mm for a length of 75 mm) to 1/125 (diameter is reduced by 1 mm for a length of 125 mm). ) Is desirable. In this embodiment, the taper ratio is 1/100. In the present embodiment, the pipe 1 and the slide member 8 have outer diameters of JIS standards of 15A to 40A.

  The union brim 2, union screw 3, union nut 4, and slide member 8 constituting the expansion / contraction union joint are made of, for example, stainless steel, and the valve (or filter part) 13 is made of brass.

  Here, the advantage of the expansion / contraction union joint according to the present embodiment will be described including the reason why the taper T of the slide member 8 is provided.

  (1) When the pipe 1 and the pipe (slide member) 8 are connected using the expansion / contraction union joint, the pipe 1 side is welded to the union collar 2 in advance, while the slide member 8 is a valve (or filter) 13 and a screw. Combined. Even when the pipes are installed and after the pipes are installed (even when both the pipe 1 and the slide member 8 are fixed in the piping system), if the lock bolt 6 is loosened, the union Since the screw 3 and the slide member 8 are allowed to move in the axial direction, the relative slide position of the union screw 3 on the slide member 8 can be easily adjusted with the pipe 1 and the slide member 8 left as they are. It can be carried out. After the position adjustment, the coupling between the pipe 1 and the pipe (slide member) 8 is completed by performing screw coupling by tightening the union nut 4 to the union screw 3.

  In this pipe connection work, the taper T described above is provided on the slide member 8, and therefore, misalignment or relative inclination between the pipe 1 and the slide member 8 during installation of the pipe (one-dot chain line in the partially enlarged view of FIG. 1). Even if such occurs, the misalignment and inclination can be absorbed by the gap generated in the taper T and the inner diameter portion of the union screw 3. When the slide member 8 is tilted with respect to the union screw 3, the annular protrusion 81 of the slide member 8 comes into contact with the inner diameter portion of the union screw 3 (point contact or line contact) as shown by the one-dot chain line in FIG. However, in this embodiment, since the outer peripheral edge of the annular protrusion 81 has a circular arc-shaped cross section, it is possible to prevent the union screw 3 and the pipe 1 from being damaged due to the one-sided contact of the slide member 8.

  In addition, when adjusting the pipe connection of the union joint, even if the slide member 8 comes into contact with the inner diameter portion of the union screw 3 in the same manner as described above due to the tightening error of the plurality of lock bolts 6, the annular protrusion 81 that becomes the contact portion. The outer peripheral curved surface portion of the slide member 8 can permit a universal tilting operation of the slide member 8. Therefore, it is possible to prevent the union screw 3 and the pipe 1 from being damaged due to the contact of the slide member 8 with each other.

  In particular, from the viewpoint of the sealing performance of the union joint, even if the gap A1 between the inner diameter portion of the union screw 3 and the annular protrusion 81 is set to a minimum, the above-mentioned contact can be allowed without any trouble.

  (2) Further, the tapered portion T has the following advantages in cooperation with the lock bolt 6. When the pressure of the fluid flowing through the pipe to be connected rises abnormally, the fluid pressure of the pipe is applied to the leading edge of the slide member 8, and the slide member 8 is pressed against the valve (or filter) 13 (see FIG. 1). The pressing force in the direction of the arrow X1 is about to act, and this pressing force is received by the lock bolt 6 by the engagement between the tapered portion T and the lock bolt 6. As a result, the abnormal pressing force in the axial direction from the slide member 8 to the valve (or filter) 13 can be prevented from acting, and damage to the piping system and the valve (or filter) can be prevented.

  (3) As described above, when the contact portion of the slide member 8 is generated at the inner diameter portion of the union screw 3 at the A1 portion, the contact distance between the self-standing sealing type packing 7 and the inner diameter portion of the union screw 3 is A gap opens (increases) on the opposite side of the generated portion, and if no consideration is given, the sealing performance may be hindered. The self-standing sealing type packing has a high hardness in order to increase the strength. For this reason, there is a slight difficulty in flexibility when the above-described contact occurs. In this embodiment, this point is dealt with by providing a fluid pressure introducing hole 83 in the annular protrusion 81. That is, conventionally, the internal pressure P1 is applied to the self-supporting sealed packing 7 through the A1 portion, but in this embodiment, the internal pressure capable of expanding the self-supporting sealing packing 7 through the fluid pressure introducing hole 83. P1 is further strengthened (that is, the fluid pressure in the pipe directly affects the internal pressure of the self-supporting sealed packing 7 through the fluid pressure introduction hole 83). Therefore, it is possible to prevent the sealing performance of the self-supporting sealing type packing 7 from being affected as much as possible and to improve the sealing performance.

  Further, the fluid pressure introducing hole 83 does not cause a differential pressure between the internal fluid pressure of the pipe and the internal pressure P1 of the self-supporting sealed packing portion even when the pressure of the fluid inside the pipe varies.

  (4) Since the self-supporting sealed packing serves as a buffer material for the union joint body, it can follow the vibration during operation of the valve (or filter) 13 and the movement during an earthquake, reducing the load on the piping system. be able to.

  In the present embodiment, the annular gap A1 between the outer diameter of the annular protrusion 81 and the inner diameter of the union screw 3; the annular gap A2 between the outer diameter of the annular protrusion 82 and the inner diameter of the union screw 3; The relationship with the annular gap A3 between the inner diameter of the union screw 3 can be set to A1 <A2 <A3. These gaps can provide a labyrinth sealing effect.

  In the above embodiment, the insertion hole of the slide member 8 in the union screw 3, particularly the inner diameter portion of the small diameter portion 3 </ b> B, may be provided with a taper that is opposite to the taper of the slide member 8.

  FIG. 9 shows an example of a fluid transfer piping system in which the union joint according to the present invention is used.

  The fluid transfer piping system in this example includes devices such as a reducer and a filter, valves such as a globe valve and a check valve, and fluid transfer system piping connected to each of them by the expansion and contraction union joint according to the present embodiment.

As shown in FIG. 9, the union joint is used in many general piping facilities including nuclear power plants, and is also a place where periodic inspection is performed. The union joint of the present embodiment can be connected to the pipe after installation, leaving the pipe as it is, loosening the union nut on the union joint side, and simply adjusting the pipe by tightening it without damaging the piping equipment. . Moreover, it is possible to replace the packing with the piping installed as it is simply by loosening and tightening the union nut. Therefore, in an enormous amount of piping equipment, the efficiency of piping installation and maintenance work can be improved. Further, in the use of equipment, highly reliable equipment operation can be realized.
(Example 2)
FIG. 4 is an upper half cross-sectional view and a partially enlarged cross-sectional view of the expansion / contraction union joint according to the second embodiment of the present invention. FIG. 5 is a perspective view of a slide member used for the expansion / contraction union joint and a self-supporting sealed packing attached thereto. FIG. 6 is a side view of the slide member as seen from the direction E of FIG.

  The basic structure of the present embodiment is the same as that of the first embodiment, and only the following points are different. Only the differences will be described below. In addition, in the code | symbol used for FIGS. 4-6, the code | symbol same as 1st Example is used about what shows the same or common element as 1st Example.

  In this embodiment, a partial arc of the annular protrusion 81 that constitutes a part of the receiving groove 80 of the self-supporting sealed packing 7 is cut as indicated by reference numeral 40. By comprising in this way, a piping fluid pressure can be guide | induced with sufficient response as an internal pressure of a self-supporting sealing type packing through the cut part 40. FIG. That is, a stronger internal pressure can be applied to the self-supporting sealed packing 7 to press the packing 7 against the inner diameter portion of the union screw 3 to enhance the sealing effect.

  Furthermore, according to the present embodiment, by cutting a part of the annular protrusion 81, even the packing 7 having a high hardness can be easily fitted into the annular groove 80, and the packing mounting work Can be simplified.

  When the cut portion 40 is provided, it is effective to omit the fluid pressure introducing hole 83 from the annular protrusion 81, and the cut portion 40 and the fluid pressure introducing hole 83 may be used in combination. .

Note that the shape of the cut portion is arbitrary, and may be, for example, a slit.
(Example 3)
FIG. 7 is an upper half cross-sectional view and a partially enlarged cross-sectional view of the expansion / contraction union joint according to the third embodiment of the present invention. FIG. 8 is a perspective view of a partial element (a member for adjusting the amount of insertion of the slide member 8) 70 of the split union screw used in the expansion / contraction union joint of this embodiment.

  The basic structure of the present embodiment is the same as that of the first embodiment, and only the following points are different. Only the differences will be described below. In addition, in the code | symbol used for FIGS. 7-8, the code | symbol same as 1st Example is used about what shows the same or common element as 1st Example.

  In the first embodiment described above, the union screw 3 used for the union joint is constituted by a single bag-shaped cylindrical member. However, in this embodiment, the union screw does not form the union screw main body 3 in a bag shape, but has an inner diameter. Is formed into a straight shape, and a portion corresponding to a bag shape of a union screw is constituted by a cylindrical member 70 having a diameter smaller than that of the main body 3. That is, the union screw is composed of two products, a main body (large diameter cylindrical member) 3 and a small diameter cylindrical member 70.

  The small-diameter cylindrical member 70 has a male screw portion 72 and a flange portion 70 </ b> A that are screw-coupled to a female screw formed on the inner diameter of the union screw main body 3.

  The position of the small diameter cylindrical member 70 in the axial direction relative to the union screw body 3 can be adjusted by the screwing amount of the small diameter cylindrical member. Thereby, the distance S between the annular protrusion 82 and the tip surface of the cylindrical part 70 can be adjusted.

  The lock bolt 6 is divided into 6A and 6B. The lock bolt 6A is provided on the union screw main body 3 and tightens the outer diameter portion (male screw portion 72) of the small diameter cylindrical member 70 so as to surround the cylindrical member 70. Stopping. On the other hand, the lock bolt 6 </ b> B is provided in the small diameter cylindrical member 70 and tightens the outer diameter portion of the slide member 8 inserted through the inner diameter of the small diameter cylindrical member 70. There are two or more of these lock bolts 6A and 6B, and they are arranged at equal intervals in the circumferential direction.

  The insertion amount of the slide member 8 with respect to the union screw 3 is adjusted via the small-diameter cylindrical member 70, whereby the pipe length (slide member) between the union joint and the valve (or filter) 13 is adjusted as in the first and second embodiments. Can be adjusted.

  Further, since the slide member 8 is provided with the same tapered portion T as in the first and second embodiments, a gap g between the inner diameter of the small-diameter cylindrical member 70 and the tapered portion T is used to The relative inclination between the slide members 8 can be absorbed.

  Further, in this embodiment, a packing, for example, a rubber packing 73 is interposed between the small diameter cylindrical member 70 and the slide member 8. In addition to functioning as a seal between the slide member 8 and the small-diameter cylindrical member 70, the packing 73 has a function of buffering one piece when the slide member 8 is inclined with respect to the small-diameter cylindrical member 70. .

FIG. 2 is a cross-sectional view of the upper half of the expansion / contraction union joint according to the first embodiment of the present invention and a partially enlarged cross-sectional view thereof. The perspective view of the tubular slide member used as one of piping of the said expansion | extension union joint, and the self-supporting sealing type packing with which it is mounted | worn. The side view which looked at the said slide member from the E direction of FIG. The upper half hook sectional view and its partially expanded sectional view of the expansion-contraction union joint which concern on 2nd Example of this invention. The perspective view of the slide member used for the said expansion / contraction union joint, and the self-supporting sealing type packing with which it is mounted | worn. The side view which looked at the said slide member from the E direction of FIG. The upper half cross-sectional view and its partial expanded sectional view of the expansion-contraction union joint which concern on 3rd Example of this invention. The perspective view of the partial element (member which adjusts the insertion amount of a slide member) 70 of the split type union screw used for the expansion-contraction union joint of 3rd Example. FIG. 9 is a configuration diagram showing an example of a fluid transfer piping system in which the union joint according to the present invention is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Piping, 2 ... Union collar, 3 ... Union screw, 4 ... Union nut, 6 ... Lock bolt, 5 ... 1st packing, 7 ... 2nd packing (self-supporting sealing type packing), 8 ... Tubular slide member, DESCRIPTION OF SYMBOLS 14 ... 1st packing (squeeze packing), 80 ... Packing accommodation groove, 81, 82 ... Cylindrical protrusion, 83 ... Pressure introduction hole, 40 ... Notch.

Claims (8)

A union nut with one open and the other bag-shaped;
A union collar inserted into the bag-like side of the union nut and connected to one piping member;
A union screw that is screw-coupled to the inner diameter portion of the union nut on the open side, and whose one end can be abutted against one end of the union collar via a first packing;
A slide member that is inserted into the inner diameter portion of the union screw via a second packing and that is a piping member that can be adjusted by sliding in the axial direction relative to the union screw. Expansion joints
The union screw is provided with a lock bolt for fastening the slide member by tightening the outer diameter portion of the slide member,
The outer diameter portion of the slide member is provided with a taper portion whose diameter decreases from the side inserted into the union screw toward the opposite side so that the tip of the lock bolt comes into contact with the taper portion. An expansion / contraction union joint characterized by comprising In claim 1,
The second packing is a self-standing sealing type packing that expands outward by an internal fluid pressure and adheres closely to the outer diameter of the slide member and the inner diameter of the union screw. Formed by two annular projections provided on the outer diameter portion of the slide member. Of the annular projections, the annular projection closer to one end of the slide member to be inserted into the union screw has an outer peripheral edge. An expansion / contraction union joint in which a curved section having a circular arc cross section is provided.   3. The pressure introducing hole according to claim 2, wherein the annular protrusion of the annular protrusion that is closer to one end of the slide member that is inserted into the union screw has a fluid pressure in a pipe that guides fluid pressure in the pipe to the self-supporting sealed packing. An expansion / contraction union joint.   4. The annular projection of claim 2 or 3, wherein the annular projection closer to one end of the slide member that is inserted into the union screw is cut into a pipe that guides the fluid pressure in the pipe to the self-supporting sealed packing. Expansion union joint with notches.   5. The union screw according to claim 1, wherein the union screw is formed by two cylindrical members that are screw-coupled, and the slide member is inserted into a cylindrical member having a smaller diameter, and this small screw. An expansion / contraction union joint provided with the lock bolt for fixing the slide member to a cylindrical member on one side. A union nut with one open and the other bag-shaped;
A union collar inserted into the bag-like side of the union nut and connected to one piping member;
A union screw that is screw-coupled to the inner diameter portion of the union nut on the open side, and whose one end can be abutted against one end of the union collar via a first packing;
A part of the union screw is inserted into the inner diameter portion of the union screw via a second packing made of a self-standing sealing type packing, and the amount of insertion becomes a piping member that can be adjusted by sliding in the axial direction relative to the union screw. In the expansion / contraction union joint provided with the slide member,
The housing groove of the self-standing sealing type packing is formed by two annular protrusions provided on the outer diameter portion of the slide member,
Among the annular protrusions, the annular protrusion closer to one end of the slide member that is inserted into the union screw has at least a pressure introduction hole and a notch for guiding the fluid pressure in the pipe to the self-supporting sealed packing. Expansion union joint with one provided. In claim 6,
An expansion / contraction union joint in which an annular protrusion, which is closer to one end of the slide member that is inserted into the union screw, is provided with a curved surface having an arcuate cross section on the outer periphery thereof.   It comprises piping system equipment and fluid transfer system piping connected with each of these by expansion union joint, and the expansion union joint consists of the expansion union joint according to any one of claims 1 to 7. Characteristic fluid transfer piping system.

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