Joint

Abstract

To provide a joint which is further reducible in size while highly maintaining seal performance.SOLUTION: A cylindrical main body of a joint is fixed to piping or a fluid apparatus, and an annular gasket is attached to an opening end face of the main body. The opening end face of the main body includes an annular groove extending along an edge of an internal peripheral side. The annular groove includes a tapered face and an external peripheral side boundary face which expands in an axial direction. The tapered face is inclined so as to move away from the opening end face of the main body to the axial direction as progressing toward an internal peripheral direction. The gasket includes a primary seal face and a secondary seal face. The primary seal face is an annular face which is inclined so that an outside diameter is contracted as moving away from a center of the gasket in the axial direction to the axial direction. The secondary seal face is included at an external peripheral face of the center part of the gasket in the axial direction, and its outside diameter is larger than the annular groove of the main body. When the gasket is pressure-inserted into the annular groove of the main body, the primary seal face tightly adheres to the tapered face of the annular groove, and the secondary seal face tightly adheres to the external peripheral side boundary face of the annular groove.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a joint for connecting a pipe or a fluid device to another pipe or a fluid device, and in particular to a seal structure thereof. [Background technology]

[0002] There are the following types of joints for connecting a pipe or a fluid device (pump, valve, flow meter, etc.) to another pipe or fluid device (see, for example, Patent Documents 1-6). The cylindrical body of the joint is fixed to the opening of the pipe to be connected, or the inlet or outlet of the fluid device (hereinafter, abbreviated as "pipe, etc."), and an annular gasket is attached to the open end face of the body. As a seal structure between the body and the gasket, an annular groove is provided along the periphery of the open end face of the body, and a gasket is embedded in the groove. A seal area is formed by the surface of the gasket being in close contact with the surface of the annular groove. In particular, there are joints in which an annular protrusion is provided along the periphery of the gasket, and the gasket is pressed into the annular groove on the open end face of the body to form a seal area between the annular protrusion and the annular groove (see, for example, Patent Documents 4-6). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2656102 [Patent Document 2] Japanese Utility Model Application Publication No. 6-49888 [Patent Document 3] Special Publication No. 2001-517287 [Patent Document 4] Patent No. 4644477 [Patent Document 5] JP 2021-148189 A [Patent Document 6] JP 2021-156428 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned joints, the gasket is attached to the opening end face of the main body, so that the opening end face of the main body needs to be sufficiently wide in order to form a sufficiently wide sealing area between the main body and the gasket in order to maintain high sealing performance between them. In particular, as in the joints disclosed in Patent Documents 4-6, joints in which the sealing area is formed between the annular protrusion of the gasket and the annular groove of the main body, not only require a large area for the opening end face of the main body, but also require a large volume for the opening of the main body. Therefore, the opening of the main body has to be wider in the outer circumferential direction than the pipes, etc. As a result, the joint is bulkier in the radial direction than the pipes, etc., making it difficult to handle the joint and restricting the layout of the piping system. Therefore, in order to make the joint easier to handle and increase the freedom of the layout of the piping system, it is desirable to make the joint smaller. However, simple miniaturization limits the area of ​​the sealing area, which impairs the sealing performance.

[0005] An object of the present invention is to solve the above problems, and in particular to provide a joint that can be further miniaturized while maintaining high sealing performance. [Means for solving the problem]

[0006] A joint according to one aspect of the present invention includes a cylindrical body and an annular gasket. The body is fixed to a pipe or a fluid device, and the gasket is attached to an open end surface of the body. The open end surface of the body includes an annular groove extending along an inner peripheral edge. The annular groove includes a tapered surface and an outer peripheral boundary surface that widens in the axial direction. The tapered surface is inclined so as to move axially away from the open end surface of the body as it progresses in the inner peripheral direction. The gasket includes a primary seal surface and a secondary seal surface. The primary seal surface is an annular surface that is inclined so that the outer diameter decreases as it moves axially away from a center portion of the gasket in the axial direction. The secondary seal surface is included in the outer peripheral surface of the center portion of the gasket in the axial direction, and has an outer diameter larger than that of the annular groove of the body. When the gasket is press-fitted into the annular groove of the body, the primary seal surface comes into close contact with the tapered surface of the annular groove, and the secondary seal surface comes into close contact with the outer peripheral boundary surface of the annular groove.

[0007] The gasket may further include a protruding portion protruding from a central portion in the axial direction toward the outer periphery. The secondary seal surface is included in the outer periphery of the protruding portion. Preferably, in a state in which the gasket is separated from the main body, the height of the protruding portion in the radial direction is designed to be such that, when the gasket is press-fitted into the annular groove of the main body, the pressure applied to the secondary seal surface from the outer periphery of the annular groove does not displace the primary seal surface in the inward periphery.

[0008] The above-mentioned joint according to the present invention may further include a cylindrical second body fixed to another pipe or another fluid device, and a connecting member for fixing the second body to the body with the gasket sandwiched therebetween. Furthermore, the connecting member may be a clamp. Preferably, when the second body is fixed to the body with the gasket sandwiched therebetween, the body and the second body maintain a predetermined distance in the axial direction on the outer circumferential side of the gasket. This distance is preferably designed so that the reduction in the inner diameter of the gasket caused by pressure from the tapered surface of the annular groove of the body is equal to or less than the allowable upper limit. Effect of the Invention

[0009] In the above joint according to the present invention, a seal area is formed between the tapered surface of the annular groove of the main body and the primary seal surface of the gasket, as well as between the boundary surface on the outer periphery of the annular groove of the main body and the secondary seal surface of the gasket. Therefore, the total area of ​​the seal area is sufficiently large. On the other hand, since the secondary seal surface is limited to the central portion in the axial direction of the gasket, the volume required for the opening of the main body is smaller than that of the structures disclosed in Patent Documents 4-6, for example, in which the combination of the annular protrusion of the gasket and the annular groove of the main body is used for sealing. Thus, the above joint according to the present invention can be further miniaturized while maintaining high sealing performance. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing the appearance of a joint according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a vertical cross-sectional view taken along line II-II in FIG. [Diagram 3]3 is a cross-sectional view taken along line III-III shown in FIG. 1. [Figure 4] FIG. 2(a) is a perspective view showing the appearance of a pair of main bodies connected to each other, and FIG. 2(b) is a perspective view showing the appearance of the pair of main bodies separated from each other. [Diagram 5] FIG. 2A is a perspective view showing the appearance of a closed clamp, and FIG. 2B is a perspective view showing the appearance of an open clamp. [Figure 6] FIG. 3 is a partially enlarged view of the vertical cross-sectional view shown in FIG. 2. [Figure 7] 1A is a partially enlarged view of a vertical cross section of a main body and a gasket immediately before they are connected, and FIG. 1B is a partially enlarged view of a vertical cross section of the main body and the gasket connected to each other. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] FIG. 1 is a perspective view showing the appearance of a fitting 100 according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view (i.e., a sectional view including the central axis) taken along line II-II in FIG. 1, and FIG. 3 is a transverse sectional view (i.e., a sectional view perpendicular to the central axis) taken along line III-III in FIG. 1. The fitting 100 is used in a piping system that handles chemicals or ultrapure water for deposition or cleaning of chips, or drying gas, for example, in a semiconductor manufacturing device, and connects a pipe or fluid device to another pipe or fluid device. The fitting 100 includes a pair of main bodies 110, 120, a gasket 200, and a connecting member 300. [Main unit]

[0012] FIG. 4(a) is a perspective view showing the appearance of a pair of main bodies 110 and 120 connected to each other, and FIG. 4(b) is a perspective view showing the appearance of the main bodies 110 and 120 separated from each other. The main bodies 110 and 120 are cylindrical members made of, for example, thermoplastic resin, and are preferably made of fluororesin such as polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE). One end 111 (left end in the figure) in the axial direction (left-right direction in the figure) of the first main body 110 is fixed to or integrated with an opening of a pipe, or an inlet or outlet of a fluid device (hereinafter abbreviated as "piping, etc."). On the other hand, the other end 112 (right end in the figure) in the axial direction of the first main body 110 has an opening, and a flange 113 extends from the periphery in the outer circumferential direction. One end 121 (right end in the figure) in the axial direction of the second main body 120 is fixed to or integrated with another pipe, etc. On the other hand, the second body 120 has an opening at the other end 122 (the left end in the figure) in the axial direction, and a flange 123 extends from the periphery of the opening in the outer circumferential direction. As shown in Figures 2 and 4, the bodies 110 and 120 are coaxially arranged so that the open end faces 114 and 124 face each other.

[0013] As shown in FIG. 2 and FIG. 4(b), annular grooves 116, 126 extend along the inner circumferential edges of the opening end faces 114, 124 of the main bodies 110, 120. The annular groove 116 of the first main body 110 is partitioned by a circular surface 117 and a tapered surface 118 on the side opposite to the opening end face 114 of the first main body 110 (the left side in the figure), and is partitioned by a boundary surface 119 on the outer circumferential side (the upper side in the figure). The circular surface 117 is parallel to the radial direction (the up-down direction in the figure). The tapered surface 118 is adjacent to the inner circumferential side (the lower side in the figure) of the circular surface 117, and is inclined so as to move away from the opening end face 114 of the first main body 110 in the axial direction (to the left in the figure) as it proceeds in the inner circumferential direction (downward in the figure). The boundary surface 119 on the outer periphery side is a cylindrical surface, and spreads in the axial direction (left and right direction in the figure) between the opening end surface 114 and the annular surface 117. The annular groove 126 of the second main body 120 is divided by the annular surface 127 and the tapered surface 128 on the side opposite to the opening end surface 124 of the second main body 120 (right side in the figure), and is divided by the boundary surface 129 on the outer periphery side (upper side in the figure). The annular surface 127 is parallel to the radial direction (up and down direction in the figure). The tapered surface 128 is adjacent to the inner periphery side (lower side in the figure) of the annular surface 127, and is inclined so as to move away from the opening end surface 124 of the second main body 120 in the axial direction (rightward in the figure) as it proceeds in the inner periphery direction (downward in the figure). The boundary surface 129 on the outer periphery side is a cylindrical surface, and spreads in the axial direction (left and right direction in the figure) between the opening end surface 124 and the annular surface 127. Preferably, as shown in FIG. 2, the annular grooves 116, 126 are equal in shape and size to one another. [gasket]

[0014] The gasket 200 is an annular member made of thermoplastic resin such as fluororesin, and is coaxially sandwiched between the opening end faces 114, 124 of the main bodies 110, 120. Preferably, as shown in FIG. 2, the longitudinal section of the gasket 200 has the same shape and size on both sides in the axial direction (left and right direction in the figure). The gasket 200 is particularly disposed in the annular grooves 116, 126 of the opening end faces 114, 124, and the surfaces are in close contact with the tapered surfaces 118, 128 of the annular grooves 116, 126 and the boundary surfaces 119, 129 on the outer periphery. As a result, as shown in FIG. 2, the internal spaces of the main bodies 110, 120 communicate with each other through the holes in the gasket 200, forming flow paths CHN for fluids such as chemicals, ultrapure water, and gases. Furthermore, the space connecting the flow channel CHN to the gap GAP between the flanges 113, 123 of the main bodies 110, 120 is sealed airtight or liquidtight by the gasket 200. Also, since the gasket 200 has the same inner diameter as the main bodies 110, 120, the walls of the flow channel CHN are smooth at the boundaries between the main bodies 110, 120 and the gasket 200. As a result, stagnation is unlikely to occur near these walls.

[0015] The gasket 200 includes a primary seal surface 210, a protruding portion 215, and a secondary seal surface 220. The primary seal surface 210 is an annular surface included in both end surfaces of the gasket 200 in the axial direction (left and right direction in the figure), and is inclined so that the outer diameter decreases as it moves away from the center portion 201 of the gasket 200 in the axial direction. When the gasket 200 is placed in the annular grooves 116, 126 of the main body 110, 120, the primary seal surface 210 is in close contact with the tapered surfaces 118, 128 of the annular grooves 116, 126. The protruding portion 215 is an annular portion that expands from the center portion 201 of the gasket 200 in the outer circumferential direction, and has an outer diameter larger than the outer boundary surfaces 119, 129 of the annular grooves 116, 126 of the main body 110, 120. As a result, the gasket 200 is placed in the annular grooves 116, 126 by press fitting. That is, the gasket 200 is coaxially pressed into the annular grooves 116, 126, and the protruding portion 215 pushes out the boundary surfaces 119, 129 on the outer periphery of the annular grooves 116, 126, thereby entering the annular grooves 116, 126. The secondary seal surface 220 is an annular surface parallel to the axial direction (the left-right direction in the drawing), and is included in the outer periphery of the central portion 201 of the gasket 200, particularly the outer periphery of the protruding portion 215. When the gasket 200 is separated from the main bodies 110, 120, the secondary seal surface 220 has an outer diameter larger than the boundary surfaces 119, 129 on the outer periphery of the annular grooves 116, 126. As a result, when the gasket 200 is pressed into the annular grooves 116, 126, the secondary seal surface 220 is brought into close contact with the boundary surfaces 119, 129 on the outer periphery. [Connecting parts]

[0016] 1 to 3, the connecting member 300 is a member, for example a clamp, that fixes the second body 120 to the first body 110 with the gasket 200 sandwiched therebetween. The clamp 300 is a cylindrical member made of a thermoplastic resin such as a fluororesin, and coaxially surrounds the entire bodies 110 and 120 that are connected to each other (see FIG. 4(a)).

[0017] FIG. 5 is a perspective view showing the appearance of the clamp 300. The clamp 300 includes a first member 310 and a second member 320. The first member 310 and the second member 320 are both semicircular ring-shaped, and base ends 311, 321 in the circumferential direction are connected to each other by a hinge. In each hinge, a shaft 323 protruding in the axial direction from the base end 321 of the second member 320 is disposed in an axial hole 313 penetrating the base end 311 of the first member 310. This allows each member 310, 320 to rotate around the hinge shaft 323, and the tip end 312 of the first member 310 and the tip end 322 of the second member 320 to be displaced between a closed position (see FIG. 5(a)) and an open position (see FIG. 5(b)). When the tip portions 312, 322 are in the closed position, both members 310, 320 form a complete ring shape. As shown in Figs. 1 to 3, the main bodies 110, 120 are sandwiched inside this ring shape. Ribs 314, 324 protrude inward from both axial ends of each member 310, 320. When the main bodies 110, 120 are sandwiched inside the ring shape formed by both members 310, 320, the flanges 113, 123 of the main bodies 110, 120 are sandwiched between the ribs 314, 324 of the clamp 300 and are tightened in the axial direction. On the other hand, when the tip portions 312, 322 are in the open position, both members 310, 320 change from a ring shape to an ω shape. This allows the clamp 300 to be removed from the main bodies 110, 120.

[0018] The clamp 300 includes a frame portion 331 and a protruding portion 332 as members for fixing the first member 310 and the second member 320 in an annular shape. The frame portion 331 is a rectangular frame provided on the tip portion 312 of the first member 310. The protruding portion 332 is a rectangular region that protrudes in the radial direction from the outer circumferential surface of the tip portion 322 of the second member 320, and forms a mountain shape along the circumferential direction of the annular shape formed by both members 310 and 320, as shown in FIG. 3. When the tip portions 312 and 322 of both members 310 and 320 are displaced from the open position to the closed position, the frame portion 331 rides over and surrounds the protruding portion 332. In this way, the frame portion 331 is caught on the protruding portion 332, and both members 310 and 320 are fixed in an annular shape. [Sealing structure between the body and gasket]

[0019] 6 is a partially enlarged view of the longitudinal section shown in FIG. 2. When the gasket 200 is sandwiched between the main bodies 110 and 120, the primary seal surface 210 is in close contact with the tapered surfaces 118 and 128. When the clamp 300 is closed around the main bodies 110 and 120 in this state, that is, when the tip portions 312 and 322 of the clamp 300 are displaced from the open position to the closed position, the ribs 314 and 324 of the clamp 300 come into contact with the flanges 113 and 123 of the main bodies 110 and 120 and apply pressure APR in the axial direction. These pressures APR are transmitted to the tapered surfaces 118 and 128 through the flanges 113 and 123, generating pressure against the primary seal surface 210, i.e., the primary seal pressure SP1. In this way, a primary seal area is formed between the tapered surfaces 118 and 128 and the primary seal surface 210, i.e., an area where the primary seal pressure SP1 reaches a level required to prevent fluid from entering the gap between those surfaces. Since the tapered surfaces 118, 128 and the primary seal surface 210 are inclined with respect to the axial direction (the left-right direction in the drawing), the area of ​​the primary seal region is sufficiently large.

[0020] In the gasket 200, the primary seal surface 210 may be displaced inward due to deformation caused by the primary seal pressure SP1, causing the edge 231 of the inner peripheral surface 230 to protrude into the flow path CHN. If the amount of protrusion, i.e., the reduction in the inner diameter ΔIR of the gasket 200, is excessive, the step generated on the wall of the flow path CHN may become excessive, which may cause excessive stagnation in the flow nearby. In the stagnation, solutes or foreign matter in the fluid are likely to solidify and accumulate as fine particles. To prevent these fine particles from flowing into the downstream piping system and products, etc. and causing adverse effects, it is necessary to minimize the step on the wall of the flow path CHN and prevent the occurrence of excessive stagnation. Therefore, even when clamp 300 is closed, gap GAP between flanges 113, 123 of main bodies 110, 120 is maintained at a predetermined distance ΔGP in the axial direction (left-right direction in the figure) so that reduction in the inner diameter of gasket 200 is kept below the upper limit of tolerance. This distance ΔGP is designed so that even if flanges 113, 123 come into contact with each other and close the gap GAP, reduction in the inner diameter ΔIR of gasket 200 reaches the upper limit of tolerance for the first time (see the two-dot chain line in FIG. 6).

[0021] Designing the gap ΔGP between the flanges 113 and 123 as described above has the following further advantage. As the shape of the gasket 200 changes over time, the clamp 300 may be replaced with one with a narrower gap between the ribs 314 and 324 in the axial direction for the purpose of retightening. In this case, the gap between the ribs 314 and 324 cannot be narrowed beyond the distance at which the flanges 113 and 123 come into contact with each other. Therefore, even with retightening, the reduction in the inner diameter ΔIR of the gasket 200 cannot exceed the allowable upper limit. Furthermore, if the flanges 113 and 123 come into contact with each other during retightening, it is understood that the reduction in the inner diameter ΔIR of the gasket 200 has reached the allowable upper limit. Therefore, the contact between the flanges 113 and 123 due to retightening can be used as a guide for replacing the gasket 200.

[0022] 7(a) is a partial enlarged view of a vertical section of the first body 110 and the gasket 200 immediately before they are connected, and FIG. 7(b) is a partial enlarged view of a vertical section of the first body 110 and the gasket 200 connected to each other. As shown in FIG. 7(a), when the gasket 200 is separated from the first body 110, the outer diameter of the protruding portion 215 of the gasket 200 is wider than the annular groove 116 of the first body 110. Therefore, as shown in FIG. 7(b), in order for the gasket 200 to be connected to the first body 110, the gasket 200 must be press-fitted into the annular groove 116. As a result, the secondary seal surface 220 of the gasket 200 is pressed inward by the boundary surface 119 on the outer circumferential side of the annular groove 116, and is subjected to the secondary seal pressure SP2. The difference in outer diameter between the outer peripheral boundary surface 119 and the secondary seal surface 220 before the gasket 200 is press-fitted into the annular groove 116, i.e., the press-fit allowance ΔPF, ensures the secondary seal pressure SP2 at a level necessary to prevent fluid from entering the gap between the outer peripheral boundary surface 119 and the secondary seal surface 220. In this way, a secondary seal area is formed between the outer peripheral boundary surface 119 and the secondary seal surface 220.

[0023] Preferably, when the gasket 200 is separated from the annular groove 116, the height HEX of the protruding portion 215 in the radial direction (the vertical direction in the drawing) is designed to be 0.2 to 5 times, more preferably 3 times, the height HPS of the primary seal face 210. If the primary seal face 210 is separated from the secondary seal face 220 to this extent, the secondary seal pressure SP2 is not transmitted to the primary seal face 210, and thus the displacement of the primary seal face 210 in the inward direction due to the secondary seal pressure SP2 is prevented. On the other hand, if the distance from the primary seal face 210 to the secondary seal face 220 is about the above-mentioned extent, the joint 100 does not become bulky in the radial direction. [Advantages of the embodiment]

[0024] In the joint 100 according to the above embodiment of the present invention, not only is a primary seal area formed between the tapered surfaces 118, 128 of the annular grooves 116, 126 of the main bodies 110, 120 and the primary seal surface 210 of the gasket 200, but also a secondary seal area is formed between the outer peripheral boundary surfaces 119, 129 of the annular grooves 116, 126 and the secondary seal surface 220 of the gasket 200. Therefore, the total area of ​​the seal area is sufficiently large. On the other hand, since the secondary seal surface 220 is limited to the central portion 201 in the axial direction of the gasket 220, the volume required for the openings 112, 122 of the main bodies 110, 120 is smaller than that of the structures disclosed in Patent Documents 4-6, for example, in which a combination of an annular protrusion of the gasket and an annular groove of the main body is used for sealing. In this way, the joint 100 can be further miniaturized while maintaining high sealing performance.

[0025] Preferably, when the gasket 200 is separated from the annular grooves 116, 126, the height HEX of the protruding portion 215 in the radial direction is designed to be 0.2 to 5 times, more preferably 3 times, the height HPS of the primary seal surface 210. This prevents the secondary seal pressure SP2 from being transmitted to the primary seal surface 210 without making the joint 100 bulky in the radial direction, and therefore prevents the primary seal surface 210 from being displaced in the inward direction due to the secondary seal pressure SP2.

[0026] Preferably, even when the clamp 300 is closed, the gap GAP between the flanges 113, 123 of the main body 110, 120 is maintained at a predetermined distance ΔGP in the axial direction. This distance ΔGP is designed so that even if the flanges 113, 123 come into contact with each other to close the gap GAP, the reduction in the inner diameter ΔIR of the gasket 200 reaches the upper limit of tolerance only at that time. Furthermore, even if the clamp 300 is replaced with one having a narrower distance between the ribs 314, 324 in the axial direction for the purpose of retightening, the distance cannot be narrowed beyond the distance at which the flanges 113, 123 come into contact with each other. Therefore, the reduction in the inner diameter ΔIR of the gasket 200 cannot exceed the upper limit of tolerance. In addition, the contact between the flanges 113, 123 due to retightening can be used as a guide for replacing the gasket 200. [Variations]

[0027] (1) The shapes of the entire joint 100 and each part shown in Figures 1 to 6 are merely examples. For example, the main body 110, 120 or the clamp 300 may be cylindrical, and the gasket 200 may be annular. The cross sections of these are not limited to circles, but may be ovals or polygons. The structure for fixing the tip portions 312, 322 of the clamp 300 in the closed position may also be various. For example, the circumferences of both the frame portion 331 and the protruding portion 332 are not limited to rectangles, but may be shapes including curves.

[0028] (2) It is not essential to the invention that the mutually connected main bodies 110, 120 are fastened with the clamp 300. The connecting member can be replaced with a member other than the clamp 300 as long as it has a well-known structure for fastening the mutually connected main bodies 110, 120. For example, the flanges 113, 123 of the main bodies 110, 120 may be fixed to each other with a bolt, or the entire main bodies 110, 120 may be surrounded and fastened with a union nut.

[0029] (3) In the gasket 200, the protruding portion 215 is provided in the central portion 201, so that the secondary seal pressure SP2 is not transmitted to the primary seal surface 210. However, if the primary seal surface 210 maintains a rigidity sufficient to prevent it from being displaced in the inward circumferential direction by the secondary seal pressure SP2, the protruding portion 215 may be omitted. In other words, the maximum outer diameter of the primary seal surface 210 and the outer diameter of the secondary seal surface 220 may be designed to be equal. [Explanation of symbols]

[0030] 100 Joints 110 First Body 111 One end of the first body 112 First body opening 113 Flange of first body 114 Open end surface of first body 116 Annular groove of first body 117 Circular surface of annular groove of first body 118 Tapered surface of annular groove of first body 119 Boundary surface on the outer periphery of the annular groove of the first body 120 Second Body 121 One end of the second body 122 Second body opening 123 Flange of second body 124 Open end surface of second body 126 Annular groove of second body 127 Circular surface of annular groove of second body 128 Tapered surface of annular groove of second body 129 Boundary surface on the outer periphery of the annular groove of the second body 200 Gasket 201 Center of gasket 210 Primary seal surface 215 Overhang 220 Secondary seal surface 300 Clamp 310 First member 311 Base end of first member 312 Tip of first member 313 Hinge hole 320 Second member 321 Base end of second member 322 Tip of second member 323 Hinge axis 331 Frame 332 Convex

Claims

1. A cylindrical main body that is fixed to a pipe or a fluid device; an annular gasket attached to an open end surface of the body; A fitting comprising: The open end surface of the body is An annular groove extending along the inner periphery and into which the gasket is press-fitted Including, The annular groove is a tapered surface that is inclined so as to move away from the open end surface in the axial direction as it progresses in an inner circumferential direction; The boundary surface on the outer periphery that spreads in the axial direction and Including, The gasket is a primary seal surface that is an annular surface that is inclined such that an outer diameter decreases with increasing distance from a central portion in the axial direction, and that comes into close contact with the tapered surface when the gasket is press-fitted into the annular groove; a secondary seal surface that is included in the outer circumferential surface of the central portion, has an outer diameter larger than that of a boundary surface on the outer circumferential side of the annular groove, and comes into close contact with the boundary surface when the gasket is press-fitted into the annular groove; Includes A joint characterized in that

2. The gasket further comprises: An annular protruding portion extending from the central portion toward the outer periphery Including, The secondary seal surface is included in an outer peripheral surface of the protruding portion.

2. The joint of claim 1.

3. a height of the protruding portion in a radial direction is designed to be such that, when the gasket is press-fitted into the annular groove in a state in which the gasket is separated from the main body, the primary seal surface is not displaced in an inward circumferential direction due to a pressure applied to the secondary seal surface from a boundary surface on an outer circumferential side of the annular groove. A joint according to claim 2.

4. A cylindrical second body that is fixed to another pipe or another fluid device; a connecting member that fixes the second body to the main body with the gasket sandwiched therebetween; The fitting of claim 1 further comprising:

5. The joint of claim 4 , wherein the connecting member is a clamp.

6. When the second body is fixed to the main body with the gasket therebetween, a predetermined distance is maintained between the main body and the second body in the axial direction on the outer circumferential side of the gasket, The interval is designed so that a reduction in the inner diameter of the gasket caused by pressure from the tapered surface is equal to or less than an allowable upper limit. A joint according to claim 4.

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