Pipe Fittings

Abstract

To provide a pipe joint in which detection sensitivity is improved, an installation work of a leak detection mechanism to a leak port is easily performed, and a leak detection sensitivity is improved.SOLUTION: A pipe joint 1 includes: first and second sleeves 10A and 10B having a flow passage communicating therebetween; an annular gasket 20 interposed between facing end faces of the sleeves 10A and 10B; a male screw member 30 having a through hole through which the first sleeve 10A is inserted; and a female screw member 40 having a through hole through which the second sleeve 10B is inserted. The sleeves 10A and 10B are coupled by screwing of the male screw member 30 and the female screw member 40. A leak port 38 for detecting a leak fluid from a gap between the sleeves 10A and 10B and the gasket 20 is provided which opens at an outer peripheral surface of the male screw member 30 that is not covered with the female screw member 40, and is connected to a gap G6 between the male screw member 30 and the first sleeve 10A.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pipe joint, and more particularly to a pipe joint having a leak port. [Background technology]

[0002] As a pipe joint for connecting various valves and pipes that require high cleanliness, chemical resistance, and sealing properties in semiconductor manufacturing equipment, for example, the joints shown in Patent Documents 1 and 2 are known. In this pipe joint, one end (joint side end) of a first and second sleeve, which are tubular materials having a flange portion and a seal portion at one end, is butted against each other via an annular gasket, and a female threaded member (cap nut) engaged with the flange portion of the first sleeve and a male threaded member (coupling) engaged with the flange portion of the second sleeve are screwed together to join and seal the two sleeves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-68269 A [Patent Document 2] JP 2016-205408 A [Patent Document 3] Japanese Utility Model Application Publication No. 5-86086 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned pipe joint, in order to detect the leak fluid from the seal part of the gasket, for example, a leak port has been provided in the cap nut. However, in this method, when the joint is fastened, the coupling is fixed to the sleeve and the cap nut is rotated, so the position of the leak port is not constant, and it is not easy to install the leak detection mechanism to the leak port after the joint is fastened. Furthermore, in pipe fittings such as those described above, the sleeves are connected to each other using a cap nut and a coupling, so there are many leak paths for the leak fluid, including threaded portions other than the leak port, and the leak fluid may leak to the outside from leak paths other than the leak port before reaching the leak port, which tends to delay leak detection and reduce detection sensitivity. For example, a method is conceivable in which leak fluid is collected in a leak port by sealing leak paths other than the leak port with an O-ring, as in the technology disclosed in Patent Document 3. However, providing an O-ring in each of the multiple leak paths in the pipe joint as described above increases the number of O-rings, and multiple O-rings must be provided in an area where multiple parts are closely spaced, which increases the number of steps.

[0005] An object of the present invention is to provide a pipe fitting which enables easy installation of a leak detection mechanism in a leak port and which has improved leak detection sensitivity. [Means for solving the problem]

[0006] A pipe joint according to the present invention comprises first and second sleeves having fluid passages communicating with each other, an annular gasket interposed between butted end faces of the first and second sleeves, a male threaded member having a through hole into which the first sleeve is inserted, and a female threaded member having a through hole into which the second sleeve is inserted, wherein the first and second sleeves are coupled together by screwing the male threaded member and the female threaded member, The male threaded member has an opening in a portion of the outer peripheral surface not covered by the female threaded member and connected to the gap between the male threaded member and the first sleeve, and has a leak port for detecting leaking fluid from between the first and second sleeves and the gasket. When the male threaded member and the female threaded member are fastened together, the male threaded member is fixed to the first and second sleeves, and the female threaded member is rotated relative to the first and second sleeves. At this time, preferably, the second seal member deforms between the first sleeve and the male threaded member, and serves as a temporary stop that restricts the rotation of the male threaded member relative to the first sleeve.

[0007] Preferably, the male screw member has a cylindrical tip portion that extends to the second sleeve and covers an outer circumferential surface of the butted portion between the first sleeve and the second sleeve, a first annular seal member that prevents the leakage fluid from leaking through a gap between the tip end of the male screw member and the second sleeve into a gap formed in a screwed portion between the male screw member and the female screw member and into a gap between the second sleeve and the female screw member; A configuration can be adopted which has a second annular seal member which is positioned toward the rear end (opposite the second sleeve) of the male threaded member relative to the position of the leak port and seals the gap between the first sleeve and the male threaded member.

[0008] More preferably, the first sealing member can be held by the female threaded member, compressed and deformed between the tip surface of the male threaded member and the female threaded member as the female threaded member is tightened, and fitted closely to the outer peripheral surface of the butt portion of the second sleeve. More preferably, the first sealing member can be configured to prevent leakage fluid from leaking through the gap between the tip end of the male threaded member and the second sleeve, through deformation, into the gap between the tip end of the male threaded member that communicates with the screw-engagement portion and the female threaded member, and into the gap between the second sleeve and the female threaded member.

[0009] Alternatively, a configuration can be adopted in which the first seal member is provided between the tip end portion of the male thread member and the abutting portion of the second sleeve.

[0010] Preferably, the first and second sleeves have flanges at their butt joints, the male screw member has a small diameter hole portion into which the first sleeve is inserted, a large diameter hole portion having a diameter larger than an inner diameter of the small diameter hole portion and receiving a flange portion of the first sleeve, and an annular engagement surface formed by a step between the small diameter hole portion and the large diameter hole portion and abutting against an annular wall surface of the flange portion of the first sleeve, A configuration can be adopted in which a groove portion is formed on a portion of the engagement surface or wall surface to connect the gap between the first sleeve and the small diameter hole portion and the gap between the flange portion and the large diameter hole portion. Also, a pipe joint of the present invention comprises first and second sleeves having fluid passages communicating with each other, an annular gasket interposed between butted end faces of the first and second sleeves, a male threaded member having a through hole into which the first sleeve is inserted, and a female threaded member having a through hole into which the second sleeve is inserted, wherein the first and second sleeves are coupled together by screwing the male threaded member and the female threaded member, The male threaded member has a leak port in a portion of its outer circumferential surface that is not covered by the female threaded member, the leak port communicating with a space in contact with the outer periphery of the gasket via a through hole in the male threaded member. Effect of the Invention

[0011] According to the present invention, a pipe fitting can be obtained which has improved detection sensitivity, facilitates the installation of a leak detection mechanism in a leak port, and also has improved leak detection sensitivity. [Brief description of the drawings]

[0012] [Figure 1] 1 is a longitudinal sectional view of a pipe joint according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a vertical cross-sectional view showing a state before fastening of the pipe joint of FIG. [Figure 3A] FIG. [Figure 3B] FIG. [Figure 4]FIG. 4 is a vertical cross-sectional view showing a modified example of the pipe joint according to the embodiment of the present invention. [Diagram 5] FIG. 11 is a vertical cross-sectional view showing still another modified example of the pipe joint according to the embodiment of the present invention. [Figure 6] FIG. 11 is a vertical cross-sectional view showing still another modified example of the pipe joint according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing a pipe joint according to this embodiment. The pipe fitting 1 comprises two sleeves 10 (10A, 10B) made of tubular material with one end abutted and having fluid passages that communicate with each other, an annular gasket 20 interposed between the abutting end faces of the sleeves 10A, 10B, a substantially cylindrical male threaded member 30 fitted onto the outer periphery of the sleeve 10A, a substantially cylindrical female threaded member 40 fitted onto the outer periphery of the sleeve 10B, an annular sealing member 50 held by the female threaded member 40, and an annular sealing member 60 held by the male threaded member 30.

[0014] The sleeve 10 has a fluid passage inside, a flange portion 11 is provided at the butted end, and a seal portion 10t is formed on the butted end face, protruding in an annular shape in the axial direction of the sleeve 10 and abutting against the gasket 20 to provide a seal. The sleeve 10 is made of a metal such as SUS316L stainless steel. A gasket 20 and a retainer 80 for holding the gasket are housed in recesses 12 formed in the butted portions of sleeves 10A and 10B, and retainer 80 is attached to recess 12 on the sleeve 10A side.

[0015] The gasket 20 is made of a metal such as a nickel alloy, and is pressed between the seal portions 10t of the sleeves 10A, 10B and is plastically deformed, thereby forming a seal between the gasket 20 and the sleeves 10A, 10B.

[0016] As shown in Fig. 3A and Fig. 3B, the male screw member 30 is a cylindrical metal member, and has a small diameter hole 31 in which the sleeve 10A is located and a large diameter hole 32 that is larger in diameter than the inner diameter of the small diameter hole 31 and receives the flange portion 11 of the sleeve 10A. An annular engagement surface 35 formed by a step between the small diameter hole 31 and the large diameter hole 32 abuts against an annular wall surface 11a on the rear end side of the flange portion 11 of the sleeve 10A. An arc-shaped groove 35a is formed in part of the circumferential direction of the engagement surface 35. This groove 35a is provided to ensure a flow path for leak fluid, as described later. A male thread 37 is formed on the outer peripheral surface of the male thread member 30, and a cylindrical tip portion 34 is formed on the tip side (right side in Fig. 3) of this male thread 37. As shown in Fig. 1, the tip portion 34 extends to (the outer peripheral surface of the flange portion 11 of) the sleeve 10B and covers the outer peripheral surface of the butted portion between the sleeves 10A and 10B. The annular tip surface 30a of the tip portion 34 presses the seal member 50 held by the sleeve 10B, as described below. A hexagonal tool engagement portion 36 for engagement with a tool is formed on the rear end face 30b side of the outer circumferential surface of the male thread member 30. A leak port 38 is formed in the tool engagement portion 36, which opens on the outer circumferential surface and communicates with the small diameter hole portion 31. The leak port 38 is internally threaded for mounting a leak detection mechanism (not shown in FIG. 1). A groove 33 into which a seal member 60 is attached is formed on the rear end surface 30b side of the small diameter hole portion 31 of the male screw member 30. The seal member 60 may be attached to a groove provided in the sleeve 10A.

[0017] 1, the female threaded member 40 is a so-called cap nut that is formed in a cylindrical shape, with a through hole 42 formed in the center of the rear end portion 41 into which the outer circumferential surface of the sleeve 10B is inserted, and a co-rotation prevention member 70 (preferably a washer or bearing) is provided between the rear end portion 41 and the flange portion 11 of the sleeve 10B. A groove 44 for mounting a seal member 50 is formed in the inner circumferential surface of the female threaded member 40 at a position adjacent to the rear end portion 41, and further, a female thread 43 that screws into the male thread 37 of the male threaded member 30 is formed on the side opposite the rear end portion 41.

[0018] The seal member 50 is made of resin, and as shown in Fig. 2, before the pipe fitting 1 is fastened, only the portion attached to the groove is deformed. When the male threaded member 30 and the female threaded member 40 are fastened, the male threaded member 30 is fixed to the sleeves 10A, 10B, and the female threaded member 40 is rotated relative to the sleeves 10A, 10B. The ends of the sleeves 10A, 10B opposite the butted portions are connected to tubes (not shown) by welding or the like. As the female thread member 40 is tightened, the sealing member 50 is compressed and deformed between the tip surface 30a of the male thread member 30 and the wall surface of the rear end portion 41 of the female thread member 40, and as shown in Figure 1, the R-shaped curved inner circumferential surface comes into close contact with the outer circumferential surface of the flange portion 11 of the sleeve 10B.

[0019] The seal member 60 is made of resin and is fitted to the outer peripheral surface of the sleeve 10A in an elastically deformed state. The seal member 60 deforms and comes into close contact with the outer peripheral surface of the sleeve 10A, whereby the seal member 60 serves as a temporary stop that restricts the rotation of the male screw member 30 relative to the sleeve 10A. This seal member 60 makes it possible to prevent the male screw member 30 from rotating relative to the sleeve 10A when the female screw member 40 is tightened.

[0020] In the pipe fitting 1, a plurality of gaps G1 to G6 are formed into which the leak fluid can enter. A gap G1 is formed between the inner peripheral surface of the large diameter hole portion 32 of the male thread member 30 and the outer peripheral surface of the flange portion 11 of the sleeve 10B. The gap G2 is formed between the outer circumferential surface of the tip portion 34 of the male threaded member 30 and the inner circumferential surface of the female threaded member 40. The gap G3 communicates with the gap G2, and is formed at the screw-engagement portion between the male thread 37 of the male-threaded member 30 and the female thread 43 of the female-threaded member 40. The gap G4 is formed between the outer circumferential surface of the sleeve 10B and the inner circumferential surface of the through hole 42 of the female thread member 40. The gap G5 is formed between the outer circumferential surface of the flange portion 11 of the sleeve 10A and the inner circumferential surface of the large diameter hole portion 32 of the male thread member 30. The gap G6 is formed between the outer circumferential surface of the sleeve 10A and the inner circumferential surface of the small diameter hole portion 31 of the male thread member 30.

[0021] The gaps G1 to G4 are in communication with each other when the seal member 50 is not present. The seal member 50 seals the gaps G1 and G2 by deforming, and prevents leakage fluid from leaking through the gap G1 to the gaps G2, G3, and G4.

[0022] The gap G5 and the gap G6 communicate with each other through a groove 35a in the engagement surface 35 of the male screw member 30. When the pipe fitting 1 is fastened, the engagement surface 35 of the male thread member 30 comes into close contact with the wall surface 11a, which may block communication between gaps G5 and G6. However, the presence of groove 35a on the engagement surface 35 of the male thread member 30 ensures communication between gaps G5 and G6.

[0023] The leak fluid that leaks to the outer periphery of the gasket 20 flows only into gap G5 because gap G1 is sealed by the sealing member 50, and passes through groove 35a and gap G6 to collect in the leak port 38. If a leak detection mechanism is provided in the leak port 38, the leak can be detected with high sensitivity.

[0024] According to this embodiment, the leak port 38 is provided in the non-rotating male screw member 30, which facilitates the installation of a leak detection mechanism in the leak port 38. In addition, since there is no path for fluid to leak other than the leak port 38, the leak detection sensitivity can be improved.

[0025] A modified example of the pipe joint of the present invention is shown in Fig. 4. Note that, among the components in Fig. 4, the same components as those in the above embodiment are designated by the same reference numerals. In the pipe fitting 1B, instead of the above-mentioned seal member 50, a seal member 50B is provided between the outer peripheral surface of the flange portion 11 of the sleeve 10B and the inner peripheral surface of the tip portion 34 of the male thread member 30 to seal the gap G1. With this configuration, it is possible to prevent leakage fluid from flowing into the gaps G2, G3, and G4 through the gap G1.

[0026] A further modified example of the pipe joint of the present invention is shown in Fig. 5. Note that, among the components in Fig. 5, the same components as those in the above embodiment are designated by the same reference numerals. In the pipe fitting 1C, instead of the leak port 38 provided in the tool engagement portion 36 of the male thread member 30, a leak port 38b is formed in a position forward of the tool engagement portion 36 and not covered by the female thread member 40.

[0027] A further modified example of the pipe joint of the present invention is shown in Fig. 6. Among the components in Fig. 6, the same components as those in the pipe joint 1 shown in Fig. 1 are designated by the same reference numerals. The pipe joint 1D differs from the pipe joint 1 shown in FIG. 1 in that the pipe joint 1D has a seal member 60 provided in a groove 10r formed in the sleeve 10A. According to this configuration, without fitting the seal member 60 to the groove 10r, in a state where the sleeve 10A is inserted into the male thread member 30, the end portion (not shown) of the sleeve 10A and the tube (not shown) can be connected by welding, and then the seal member 60 can be fitted to the groove 10r. As a result, it is possible to prevent the seal member 60 from being affected by heat due to welding.

[0028] The present invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0029] 1, 1B, 1C, 1D: Pipe fittings 10, 10A, 10B: Sleeve 10t: Seal part 10r: Groove 11: Flange part 11a: Wall 12: Recess 20: Gasket 30: Male threaded member 30a: Tip surface 30b: Rear end surface 31: Small diameter hole (through hole) 32: Large diameter hole 33: Groove 34:Tip 35: Engagement surface 35a: Groove 36: Tool engagement part 37: Male thread 38,38b:Leak port 40: Female threaded member 41: Rear end 42:Through hole 43: Female thread 44: Groove 50, 50B, 60: Sealing material 70: Anti-rotation parts 80: Retainer G1-G6: Gap

Claims

1. a pipe joint comprising first and second sleeves having fluid passages communicating with each other, an annular gasket interposed between butted end faces of the first and second sleeves, a male threaded member having a through hole into which the first sleeve is inserted, and a female threaded member having a through hole into which the second sleeve is inserted, wherein the first and second sleeves are coupled together by screwing the male threaded member and the female threaded member, A pipe fitting having a leak port for detecting leaking fluid from between the first and second sleeves and the gasket, the leak port opening in a portion of the outer peripheral surface of the male threaded member that is not covered by the female threaded member and connected to a gap between the male threaded member and the first sleeve.

2. 2. The pipe fitting according to claim 1, wherein when the male threaded member and the female threaded member are fastened together, the male threaded member is fixed relative to the first and second sleeves and the female threaded member is rotated relative to the first and second sleeves.

3. the male screw member has a cylindrical tip portion that extends to the second sleeve and covers an outer circumferential surface of an abutting portion between the first sleeve and the second sleeve, a first annular seal member that prevents the leakage fluid from leaking through a gap between the tip end of the male screw member and the second sleeve into a gap formed in a screwed portion between the male screw member and the female screw member and into a gap between the second sleeve and the female screw member; 3. The pipe fitting according to claim 1, further comprising: an annular second seal member that is arranged on a rear end side of a position of the leak port of the male threaded member and seals a gap between the first sleeve and the male threaded member.

4. 4. The pipe joint according to claim 3, wherein the second seal member deforms between the first sleeve and the male threaded member and serves as a temporary stop that restricts rotation of the male threaded member relative to the first sleeve.

5. 5. The pipe fitting according to claim 3, wherein the first seal member is held by the female-threaded member, and is compressed and deformed between the tip surface of the male-threaded member and the female-threaded member as the female-threaded member is tightened, and is brought into close contact with an outer peripheral surface of the butt portion of the second sleeve.

6. 6. The pipe fitting according to claim 4 or 5, wherein the first seal member, by deformation, prevents leakage fluid from leaking through the gap between the tip end of the male threaded member and the second sleeve, into the gap between the tip end of the male threaded member that communicates with the threaded portion and the female threaded member, and into the gap between the second sleeve and the female threaded member.

7. 4. The pipe joint according to claim 3, wherein the first seal member is provided between a tip end of the male thread member and an abutting portion of the second sleeve.

8. The first and second sleeves have flanges at their butt joints, the male screw member has a small diameter hole portion into which the first sleeve is inserted, a large diameter hole portion having a diameter larger than an inner diameter of the small diameter hole portion and receiving a flange portion of the first sleeve, and an annular engagement surface formed by a step between the small diameter hole portion and the large diameter hole portion and abutting against an annular wall surface of the flange portion of the first sleeve, 4. The pipe fitting according to claim 1, wherein a groove portion is formed in a portion of the engagement surface or wall surface to connect a gap between the first sleeve and the small diameter hole portion and a gap between the flange portion and the large diameter hole portion.

9. a pipe joint comprising first and second sleeves having fluid passages communicating with each other, an annular gasket interposed between butted end faces of the first and second sleeves, a male threaded member having a through hole into which the first sleeve is inserted, and a female threaded member having a through hole into which the second sleeve is inserted, wherein the first and second sleeves are coupled together by screwing the male threaded member and the female threaded member, a leak port in a portion of the outer peripheral surface of the male threaded member that is not covered by the female threaded member, the leak port communicating with a space in contact with the outer periphery of a gasket via a through hole in the male threaded member.

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