JP6599573B1 - Piping joint mechanism and piping joint - Google Patents

Abstract

An object of the present invention is to reduce the replacement frequency of a pipe joint and a connection destination member that are connected to a connection destination member by screw joint. A pipe joint is a tubular member and is provided so as to protrude from a through hole forming a flow path, a flange portion through which the through hole passes, and a surface of the flange portion on the side of the connection end. A sleeve having a protruding portion through which the through-hole passes and an opening of the through-hole is provided at a protruding tip, and a tubular member that covers a part of the sleeve from the outer periphery, the end on the connection end side being the end The flange portion has a portion that comes into contact with the surface on the pipe side, and is disposed so as to surround the outer periphery of the convex portion and the fastening member provided with the screw portion on the outer periphery for screw joining to the connection destination member. A ring-shaped gasket. By tightening with the tightening member, before the protruding tip of the sleeve abuts on the connection destination member and exerts the function of a line seal, the opposing surface is pressed and deformed to deform the face seal. Demonstrate the function. [Selection] Figure 1

Description

  The present invention relates to a pipe joint mechanism that is interposed between a pipe and a flow path of a connection destination member and includes a pipe joint and a connection destination member that are connected to the connection destination member by screw joining, and a pipe joint.

  When connecting the high-pressure gas pipe to the connection destination member, a pipe joint is used so that there is no leakage of the high-pressure gas. The pipe joint is interposed between the pipe and the flow path of the connection destination member, and is configured to be connected to the connection destination member by screw bonding. In particular, in a high-pressure hydrogen station that supplies hydrogen gas as fuel to a fuel cell vehicle, when connecting a pipe through which high-pressure hydrogen gas flows and a connection destination member, it is required to completely seal the hydrogen gas so that it does not leak. It is done.

  For example, in the general high-pressure gas example standard 26 in Article 7, Paragraph 3 of the General Rules for the High-Pressure Gas Safety Law, it is obliged to use a limited screw joint structure. The hydrogen gas in the compressed hydrogen stand is pressurized to a pressure of 82 MPa, for example. In such a high-pressure gas, a well-known cone / thread type is used as the structure of the pipe joint. A cone-thread type pipe joint uses a metal seal wire seal structure.

  However, in a pipe joint having a wire seal structure by metal touch, extremely high contact pressure is applied between the members that come into contact with each other, so that the plastic deformation of the contact portion between the pipe joint and the connection destination member is large and a flaw is formed. Such plastic deformation or damage is a cause of gas leakage when the pipe joint is repeatedly fastened and detached.

  On the other hand, it is suitable for the flow path of high-pressure fluid, and prevents high-pressure fluid leakage by providing high sealing performance while preventing deformation and breakage of the gasket and connecting end side due to excessive tightening force. There has been proposed a high-pressure pipe joint that can be easily prevented and pipe construction is easy (Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-14468

The high-pressure pipe joint has a structure in which the connection end surfaces of a pair of tubular members are sealed and connected by tightening a screw member via a gasket. The gasket is a metal whose hardness is lower than that of the connecting end surface, and a narrow flat seal portion is formed on the inner end or in the vicinity of the innermost end surface, and an obtuse angle tapered surface is formed along the outer diameter side of the narrow flat seal portion. Form. When the screw member is tightened, it is sealed in a state where the seal part of the gasket is expanded with a narrow flat seal part and an obtuse angle taper surface depending on the size of the tightening load, and when tightened with the maximum tightening load, the outer diameter The seal structure is such that the obtuse angle taper surface on the side serves as a stopper, and is configured to maintain the sealing performance even for ultra-high pressure fluid.
The high-pressure pipe joint has a so-called face seal structure in which sealing is performed by tightening a screw member via a gasket. For this reason, it cannot be used in combination with a cone-thread type pipe joint for connecting a high-pressure gas pipe using a metal seal line seal structure to a connection destination member. The line seal refers to a seal form in which the abutting part is linear, and the surface seal refers to a seal form in which the abutting part is planar like a gasket surface.

  Therefore, the present invention is a pipe joint that is interposed between the pipe and the flow path of the connection destination member and is connected to the connection destination member by screw joining, and has a contact portion that has the above-described line seal structure and exhibits a sealing function An object of the present invention is to provide a pipe joint mechanism and a pipe joint that can reduce the frequency of replacement of the pipe joint and the connection destination member.

One aspect of the present invention is a pipe joint mechanism including a pipe joint that is interposed between a pipe and a flow path of a connection destination member and is connected to the connection destination member by screw joint and the connection destination member.
The connecting member is
A recess that becomes a part of the flow path of the connection destination member;
A connecting thread portion provided on the inner peripheral surface of the recess,
An opening of a hole which is provided on the bottom side of the recess and is surrounded by a bottom surface provided on the bottom side of the recess, which becomes a part of the flow path;
With
The pipe joint is
A tubular member, a through hole forming a flow path extending from an end on the pipe side toward a connection end side with the connection destination member, and an outer periphery of the tubular member, the through hole being provided A flange portion that passes through, and a convex portion that is provided on the surface of the tubular member on the side of the connection end so as to protrude toward the connection end, and that has a through hole that passes through the through hole and is provided with an opening of the through hole. A sleeve having
A tubular member that covers from the outer periphery a portion of the sleeve that is closer to the pipe than the flange, and has a portion that contacts the pipe side of the flange at the end of the connection end; A tightening member provided on the outer periphery with a thread portion for joining with the connection destination screw of the connection destination member;
A ring-shaped gasket disposed on the base of the convex portion on the side of the connection end of the sleeve on the opposite surface facing the bottom surface of the connection destination member so as to surround the outer periphery of the convex portion; .
At this time, the edge of the opening is provided with an inclined surface having the shape of the side surface of the truncated cone along the circumference of the opening.
The convex portion is configured such that a corner portion of the projecting tip is in contact with the inclined surface of the edge of the opening of the connection destination member and can be sealed linearly around the edge of the opening,
By the tightening of the pipe joint by the tightening member to the recess of the connection destination member, the projecting tip of the sleeve approaches the connection destination member and contacts the connection destination member before the connection surface and the connection destination. It is configured to seal between the through hole and the flow path of the connection destination member by pressing and deforming the gasket between the member and the opposing surface ,
The convex portion protrudes in a truncated cone shape so that a cross-section becomes smaller toward the connection end side from the columnar protruding portion standing vertically from the facing surface, and the protruding tip. A frustoconical protrusion having
The thickness dimension of the gasket is shorter than the protruding length of the cylindrical protrusion,
The protrusion height of the columnar protrusion is such that when the protrusion tip abuts the connection destination member, a part of the columnar protrusion is located in the space of the hole surrounded by the inclined surface. Is stipulated.

  It is preferable that the thickness of the gasket is larger than the separation distance between the facing surface and the bottom surface when the protruding tip comes into contact with the edge of the opening by tightening the tightening member.

  It is preferable that a diameter of a portion of the protruding tip that comes into contact with the connection destination member is smaller than an inner diameter of the ring-shaped gasket.

Another aspect of the present invention is a pipe joint that is interposed between a pipe and a flow path of a connection destination member and is connected to the connection destination member by screw bonding. The pipe joint is
A tubular member, a through hole forming a flow path extending from an end on the pipe side toward a connection end side with the connection destination member, and an outer periphery of the tubular member, the through hole being provided A flange portion that passes through, and a convex portion that is provided on the surface of the flange portion on the side of the connection end so as to protrude toward the connection end, and that has a through hole that passes through the through hole. A sleeve having
A tubular member that covers from the outer periphery a portion of the sleeve that is closer to the pipe than the flange portion, the end of the connecting end has a portion that contacts the surface of the flange of the pipe; A tightening member provided on the outer periphery with a screw portion for screw joining with the connection destination member;
A ring-shaped gasket disposed on an opposing surface facing the connection destination member provided on the connection end side of the sleeve so as to surround the outer periphery of the convex portion;
The convex portion is configured such that a corner portion of the projecting tip comes into contact with an inclined surface at an edge of the opening of the connection destination member and can be sealed linearly around the edge of the opening,
By tightening the pipe joint to the connection destination member by the clamping member, before the protruding tip of the sleeve approaches the connection destination member and abuts on the connection destination member, the opposing surface and the connection destination member It is configured to seal between the through hole and the flow path of the connection destination member by pressing and deforming the gasket in between.
The convex portion protrudes in a truncated cone shape so that a cross-section becomes smaller toward the connection end side from the columnar protruding portion standing vertically from the facing surface, and the protruding tip. A frustoconical protrusion having
The thickness dimension of the gasket is shorter than the protruding length of the cylindrical protrusion,
The protrusion height of the columnar protrusion is such that when the protrusion tip abuts the connection destination member, a part of the columnar protrusion is located in the space of the hole surrounded by the inclined surface. Is stipulated.

  According to the above-described pipe joint mechanism and pipe joint, the deformation of the abutting portion that has a line seal structure and exhibits a sealing function is small, and the replacement frequency of the pipe joint and the connection destination member can be reduced.

It is an external appearance perspective view of the piping joint mechanism of one embodiment. It is a perspective view which shows the cross section of the piping joint of one Embodiment, and a connecting point member. It is an enlarged view which shows the sleeve of the piping joint of one Embodiment. It is a figure explaining an example of modification of a gasket when a face seal functions in one embodiment.

  Hereinafter, a pipe joint mechanism and a pipe joint according to an embodiment will be described with reference to the drawings. FIG. 1 is an external perspective view of a pipe joint mechanism including a pipe joint and a connection destination member. FIG. 2 is a perspective view illustrating a cross section of a pipe joint and a connection destination member according to an embodiment. FIG. 3 is an enlarged view showing a sleeve of a pipe joint according to an embodiment.

  A pipe joint mechanism 1 shown in FIG. 1 includes a pipe joint 10 that is interposed between the pipe 2 and the flow path of the connection destination member 30 and is connected to the connection destination member 30 by screw joining, and the connection destination member 30. . The connection destination member 30 is a member provided with a high-pressure valve or the like used in a high-pressure hydrogen station or the like, and has a complicated shape, but is represented in a cubic shape in the figure for easy understanding.

The connection destination member 30 is a portion that is connected to the pipe joint 10 and includes a recess 32 that is a part of a gas flow path in the connection destination member 30. Further, the connection destination member 30 is connected to the connection destination screw portion 34 provided on the inner peripheral surface of the recess 32, the bottom surface 36 provided on the bottom side of the recess 32, and provided on the bottom side of the recess 32, and surrounded by the bottom surface 36. And an opening 38 of a hole that becomes a part of the flow path, and an inclined surface 40 that is provided along the circumference of the opening 30 as an edge of the opening 38 and is inclined with respect to the bottom surface 36.
The illustration of the thread of the connecting thread portion 34 provided on the inner peripheral surface of the recess 32 is omitted.

The pipe joint 10 includes a sleeve 12, a fastening member 14, and a gasket 16.
The sleeve 12 is a tubular member, and a through hole 18 (see FIG. 2) is provided inside the sleeve 12. The part with one opening of the through hole 18 is connected to the pipe 2 by welding. A portion of the through hole 18 having the other opening is provided at a protruding tip of a convex portion 22 described later. The protruding tip of the convex portion 22 is configured to be inserted into the concave portion 32 of the connection destination member 30 as will be described later. Therefore, the through hole 18 forms a flow path of a fluid such as a gas extending from the end on the pipe 2 side toward the connection end with the connection destination member 30.

The sleeve 12 further includes a flange portion 20 and a convex portion 22.
The flange portion 20 is provided in a hook shape on the outer periphery of the sleeve 12 on the connection end side where the sleeve 12 is connected to the connection destination member 30. The through hole 18 passes through the flange portion 20.
The convex portion 22 is provided on the surface of the sleeve 12 on the connection end side where the sleeve 12 is connected to the connection destination member 30 so as to protrude toward the connection end. The through-hole 18 passes through the convex portion 22, and an opening of the through-hole 18 is provided at the protruding tip of the convex portion 22.

  As shown in FIG. 2, the tightening member 14 is a tubular member that covers a portion closer to the pipe 2 than the flange portion 20 of the sleeve 12 from the outer periphery. The sleeve 12 is loosely fitted in the hole of the fastening member 14. The outer diameter of the fastening member 14 is larger than the outer diameter of the flange portion 20. The tightening member 14 is provided with a screw portion 24 (see FIG. 2) on the outer periphery for screw-joining with a recess 32 that is a part of the flow path of the connection destination member 30. In FIG. 2, the illustration of the thread of the screw portion 24 is omitted. A gland nut 28 is formed on the pipe 2 side of the screw portion 24. The convex portion 22, the flange portion 20, and a part of the fastening member 14 of the pipe joint 10 are inserted into the concave portion 32 of the connection destination member 30, and by rotating the ground nut 28 with a wrench or the like, the screw portion 24 is The connecting member 30 is configured to be screwed to a connecting screw portion 34 provided on the inner peripheral surface of the concave portion 32 of the connecting member 30 and move the tightening member 14 to the connecting end side to be tightened. On the other hand, the end on the connection end side of the fastening member 14 is configured to abut on the surface of the flange portion 20 on the pipe 2 side. Therefore, when the fastening member 14 moves the sleeve 12 toward the concave portion 32, the sleeve 12 moves toward the concave portion 32, and the gap between the facing surface 26 and the bottom surface 36 is gradually narrowed.

  The gasket 16 (see FIGS. 2 and 3) is a ring-shaped thin plate member, and the outer periphery of the convex portion 22 is formed on the opposing surface 26 provided on the connection end side of the sleeve 12, which faces the bottom surface 36 of the concave portion 32. It is arranged to surround. The gasket 16 is made of malleable metal having a lower hardness than the sleeve 12 and the connection destination member 30. For example, the sleeve 12 and the connection destination member 30 are made of stainless steel, and the gasket 16 is made of copper or aluminum.

Here, in the pipe joint 10, the convex portion 22 is inserted into the concave portion 32, and the projecting tip of the convex portion 22 opens the flow path provided at the bottom of the concave portion 32 of the connection destination member 30 by tightening by the tightening member 14. The projecting height of the projecting portion 22 and the shape of the projecting tip of the projecting portion 22 are such that the space between the through hole 18 and the flow path of the connection destination member 30 can be sealed by abutting the surrounding inclined surface 40. It is configured. The inclined surface 40 has the shape of the side surface of the truncated cone.
In addition, the clamping member 14 is positioned between the facing surface 26 and the bottom surface 36 before the protruding tip of the sleeve 12 approaches the connection destination member 30 and abuts against the inclined surface 40 (edge of the opening) of the recess 32. The gasket 16 is configured to be sealed (face seal) between the through hole 12 and the flow path of the connection destination member 30 by the opposing surface 26 being pressed and deformed.

  Since it is configured in this way, the gasket 16 is deformed to fill a gap between the connection destination member 30 and the sleeve 12 and to seal the surface between the through hole 18 and the flow path of the connection destination member 30. it can. On the other hand, when the degree of tightening by the tightening member 14 is weak, the gasket 16 is deformed and performs surface sealing, but does not come into contact with the inclined surface 40 of the recess 32 and does not exhibit the function of line sealing. Although only such a face seal functions, gas leakage can be prevented, but in order to prevent gas leakage more fully or to prevent gas leakage of high-pressure gas completely, the fastening member 14 is used. By further increasing the tightening force, the projecting tip of the convex portion 22 abuts on the inclined surface 40 formed in the concave portion 32 of the connection destination member 30, so that in addition to the face seal by the gasket 16, the through hole 18 and the connection destination member 30. It is possible to seal (line seal) between the two channels. These can be properly used depending on the tightening torque of the ground nut 28.

When the line seal is made to function, since the surface seal has already functioned, it is possible to prevent gas leakage without applying a tightening force for making the conventional line seal function. Moreover, even if the tightening force by the tightening member 14 is about the same as the conventional one, the gasket 16 bears a part of the tightening force, so that the pressure at which the projecting tip of the convex portion 22 contacts the inclined surface 40 of the concave portion 32 is reduced. . For this reason, it can suppress that an abutting part plastically deforms conventionally, and a damage | wound generate | occur | produces. Therefore, the deformation of the contact portion that exhibits the function of the wire seal is small, and the replacement frequency of the pipe joint and the connection destination member can be reduced. When the pipe joint is fastened and removed, it is not necessary to replace it with a new pipe joint. Therefore, it is not necessary to separate the pipe 2 and the pipe joint 10 connected by welding, and the deformed gasket 16 is replaced. Only good.
As described above, the pipe joint mechanism 1 of the present embodiment can first exert the face seal function, and if the gas leakage cannot be prevented, the tightening by the tightening member 14 can be strengthened so that the line seal function is exhibited. it can.

  Since the surface sealing function and the line sealing function are exhibited in this way, the thickness of the gasket 16 is such that the projecting tip of the convex portion 22 contacts the inclined surface 40 when the screw portion 24 is tightened, and the opposing surface 26 and the bottom surface 36. Is preferably greater than the separation distance between the two. Thereby, the gasket 16 is crushed in the thickness direction and extends to the inner hole side and the outer peripheral side of the ring-shaped gasket 16 so as to fill the gap. Thereby, the function of a face seal can be exhibited.

  Further, according to one embodiment, the convex portion 22 has a columnar protruding portion 22A (see FIG. 3) erected vertically from the facing surface 26, and a cross section from the columnar protruding portion 22A toward the connection end. And a frustoconical protrusion 22B (see FIG. 3) that protrudes into a frustoconical shape and has a protruding tip. At this time, the thickness dimension of the gasket 16 is preferably shorter than the protruding length of the cylindrical protruding portion 22A.

FIG. 4 is a diagram for explaining an example of the deformation of the gasket 16 when the face seal functions.
The inclination angle of the inclined surface 40 provided around the opening of the flow path of the joining member 30 is such that the corner of the protruding tip of the convex portion 22 abuts and exhibits the function of a line seal. It is gently inclined with respect to the inclination angle of the inclined surface. For this reason, the gap between the inclined surface 40 and the inclined surface of the frustoconical protruding portion 22B increases as it proceeds from the protruding tip of the protruding portion 22 toward the base portion of the protruding portion 22. Due to the malleability of the gasket 16 that is crushed by the tightening of the tightening member 14, the gasket 16 extends to the gap between the inclined surface 40 and the inclined surface of the truncated cone-shaped protrusion 22 </ b> B rather than extending to the outer periphery of the gasket 16. It is preferable for further improving the function. When the thickness dimension of the gasket 16 is shorter than the protruding length of the columnar protrusion 22A, the inclined surface 40 is compared with the case where the thickness dimension of the gasket 16 is equal to or larger than the protruding length of the columnar protrusion 22A. The gap with the inclined surface of the frustoconical protrusion 22B is large. Therefore, by making the thickness dimension of the gasket 16 shorter than the projecting length of the cylindrical projecting portion 22A, it is possible to secure a space extending to the gap of the gasket 16 to be crushed. Is shorter than the protruding length of the cylindrical protruding portion 22A from the viewpoint of exerting a sealing function.

According to one embodiment, it is preferable that the diameter of the portion contacting the inclined surface 40 at the protruding tip of the convex portion 22 is smaller than the inner diameter of the ring-shaped gasket 16.
The portion that contacts the inclined surface 40 at the projecting tip of the convex portion 22 is a portion that exerts the function of the line seal when the function of the surface seal by the gasket 16 is not sufficient, and therefore it is preferable to contact with a high contact pressure. For this reason, it is preferable that the diameter of the abutting portion of the projecting tip of the convex portion 22 that effectively exhibits the function of gas leakage by the line seal is smaller than the inner diameter of the gasket 16 that exhibits the function of the face seal.

  As described above, in this embodiment, before the projecting tip of the convex portion 22 of the sleeve 12 approaches the connection destination member 30 and abuts on the connection destination member 30 by tightening by the fastening member 14 that moves the pipe joint 10 to the concave portion 32, The gasket between the opposing surface 26 and the connection destination member 30 (bottom 36) is configured to seal between the through hole 18 and the flow path of the connection destination member 30 when the opposing surface 26 presses and deforms the gasket. can do. For this reason, it has a seal structure and the deformation | transformation of the contact part which exhibits a sealing function is small, and it can reduce the replacement frequency of a pipe joint and a connecting point member.

  As described above, the pipe joint mechanism and the pipe joint of the present invention have been described in detail. However, the present invention is not limited to the above embodiment, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

DESCRIPTION OF SYMBOLS 1 Piping joint mechanism 2 Piping 10 Piping joint 12 Sleeve 14 Tightening member 16 Gasket 18 Through-hole 20 Flange part 22 Protruding part 24 Screw part 26 Opposing surface 28 Ground nut 30 Connection destination member 32 Concavity part 34 Connection tip thread part 36 Bottom face 38 Opening 40 Inclined surface

Claims (4)

It is a pipe joint mechanism that is interposed between the pipe and the flow path of the connection destination member, and includes a pipe joint that is connected to the connection destination member by screw joint and the connection destination member.
The connecting member is
A recess that becomes a part of the flow path of the connection destination member;
A connecting thread portion provided on the inner peripheral surface of the recess,
An opening of a hole that is provided on the bottom side of the recess and is surrounded by a bottom surface provided on the bottom side of the recess;
With
The pipe joint is
A tubular member, a through hole forming a flow path extending from an end on the pipe side toward a connection end side with the connection destination member, and an outer periphery of the tubular member, the through hole being provided A flange portion that passes through, and a convex portion that is provided on the surface of the tubular member on the side of the connection end so as to protrude toward the connection end, and that has a through hole that passes through the through hole and is provided with an opening of the through hole. A sleeve having
A tubular member that covers from the outer periphery a portion of the sleeve that is closer to the pipe than the flange, and has a portion that contacts the pipe side of the flange at the end of the connection end; A tightening member provided on the outer periphery with a thread portion for joining with the connection destination screw of the connection destination member;
A ring-shaped gasket disposed at a base portion of the convex portion on the side of the connection end of the sleeve on a facing surface facing the bottom surface of the connection destination member so as to surround an outer periphery of the convex portion; ,
The edge of the opening is provided with an inclined surface in the shape of the side surface of the truncated cone along the circumference of the opening,
The convex portion is configured such that a corner portion of the projecting tip is in contact with the inclined surface of the edge of the opening of the connection destination member and can be sealed linearly around the edge of the opening,
By the tightening of the pipe joint by the tightening member to the recess of the connection destination member, the projecting tip of the sleeve approaches the connection destination member and contacts the connection destination member before the connection surface and the connection destination. It is configured to seal between the through hole and the flow path of the connection destination member by pressing and deforming the gasket between the member and the opposing surface,
The convex portion protrudes in a truncated cone shape so that a cross-section becomes smaller toward the connection end side from the columnar protruding portion standing vertically from the facing surface, and the protruding tip. A frustoconical protrusion having
The thickness dimension of the gasket is shorter than the protruding length of the cylindrical protrusion,
The protrusion height of the columnar protrusion is such that when the protrusion tip abuts the connection destination member, a part of the columnar protrusion is located in the space of the hole surrounded by the inclined surface. It is defined, the pipe joint mechanism, characterized in that.   2. The pipe joint mechanism according to claim 1, wherein a thickness of the gasket is larger than a separation distance between the facing surface and the bottom surface when the protruding tip comes into contact with an edge of the opening by fastening of the fastening member. . The pipe joint mechanism according to claim 1 or 2 , wherein a diameter of a portion of the protruding tip that comes into contact with the connection destination member is smaller than an inner diameter of the ring-shaped gasket. A pipe joint interposed between the pipe and the flow path of the connection destination member, and connected to the connection destination member by screw bonding,
A tubular member, a through hole forming a flow path extending from an end on the pipe side toward a connection end side with the connection destination member, and an outer periphery of the tubular member, the through hole being provided A flange portion that passes through, and a convex portion that is provided on the surface of the flange portion on the side of the connection end so as to protrude toward the connection end, and that has a through hole that passes through the through hole. A sleeve having
A tubular member that covers from the outer periphery a portion of the sleeve that is closer to the pipe than the flange portion, the end of the connecting end has a portion that contacts the surface of the flange of the pipe; A tightening member provided on the outer periphery with a screw portion for screw joining with the connection destination member;
A ring-shaped gasket disposed on an opposing surface facing the connection destination member provided on the connection end side of the sleeve so as to surround the outer periphery of the convex portion;
The corner of the projecting tip is in contact with the inclined surface having the shape of the side surface of the truncated cone at the edge of the opening of the connection destination member, so that the periphery of the edge of the opening can be linearly sealed. The convex portion is configured,
By the tightening of the pipe joint to the connection destination member by the tightening member, before the protruding tip of the sleeve approaches the connection destination member and contacts the connection destination member, the opposing surface and the connection destination member It is configured to seal between the through hole and the flow path of the connection destination member by pressing and deforming the gasket in between.
The convex portion protrudes in a truncated cone shape so that a cross-section becomes smaller toward the connection end side from the columnar protruding portion standing vertically from the facing surface, and the protruding tip. A frustoconical protrusion having
The thickness dimension of the gasket is shorter than the protruding length of the cylindrical protrusion,
The protrusion height of the columnar protrusion is such that when the protrusion tip abuts the connection destination member, a part of the columnar protrusion is located in the space of the hole surrounded by the inclined surface. It is defined, pipe fittings, characterized in that.

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