Gasket and flow passage joint structure

Abstract

The present disclosure pertains to a gasket for sealing and connecting flow path holes respectively formed in two fluid devices. The gasket is provided with: an inner peripheral surface that is made of a conductive material, is disposed between the flow path holes, and comes into contact with a transferred fluid; and a pair of annular seal parts that are provided on both sides in the axial direction and are in close contact with annular seal grooves respectively formed at connection ends of the flow path holes of both the fluid devices.

Description

Gasket and flow path joint structure

[0001] This application claims priority to Japanese Patent Application No. 2024-032289, filed on March 4, 2024, and incorporates by reference all of the contents of said Japanese application.

[0002] In manufacturing equipment in various technical fields such as semiconductor manufacturing and medical / pharmaceutical manufacturing, a flow path joint (ground joint) described in Patent Document 1 (see FIG. 6) is known as a connection structure for connecting flow path holes formed in fluid devices such as tubes and diaphragm pumps. The flow path joint in Patent Document 1 has a through hole formed in its peripheral wall, and an electrode rod is inserted into this through hole. When the transport fluid flowing through the flow path joint comes into contact with the electrode rod, the electric charge on the transport fluid is discharged to the electrode rod.

[0003] Japanese Patent Application Laid-Open No. 2008-235301

[0004] In the above-mentioned flow path joint, when the transfer fluid flows through the flow path joint, the transfer fluid tends to accumulate in the gap between the through hole of the flow path joint and the electrode rod, and if the transfer fluid accumulates in the gap, the replaceability of the transfer fluid decreases.

[0005] An object of the present disclosure is to provide a gasket and a flow path joint structure that can discharge electric charges stored in a transport fluid while suppressing a decrease in the replaceability of the transport fluid.

[0006] (1) The gasket disclosed herein is a gasket that seals and connects flow path holes formed in two fluid devices, and is made of a conductive material and is arranged between the flow path holes. The gasket has an inner surface that comes into contact with the transport fluid, and a pair of annular seal portions that are provided on both axial sides and that fit tightly into annular seal grooves formed at the connection ends of the flow path holes of both fluid devices.

[0007] According to the gasket of the present disclosure, when the transfer fluid comes into contact with the inner peripheral surface of the gasket made of a conductive material, the charge on the transfer fluid can be discharged to the gasket. Furthermore, a pair of seals provided on both axial sides of the gasket are in close contact with seal grooves formed at the connection ends of the flow path holes of each fluidic device. This prevents the transfer fluid from accumulating at the connection portions between each fluidic device and the gasket. As a result, the replacement of the transfer fluid can be prevented from decreasing.

[0008] (2) The gasket of (1) above preferably further comprises a rib provided on the inner circumferential surface and in contact with the transfer fluid. In this case, the transfer fluid comes into contact with the rib as well as the inner circumferential surface of the gasket, so that the electric charge on the transfer fluid can be efficiently discharged to the gasket.

[0009] (3) The gasket of (1) or (2) preferably further comprises an annular gasket body having the inner peripheral surface and a ground terminal extending radially outward from the gasket body, in which case electric charges discharged from the transported fluid to the gasket body can be released to the ground from the ground terminal.

[0010] (4) The flow path joint structure of the present disclosure comprises a gasket described in any one of (1) to (3) that seals and connects flow path holes formed in two fluid devices, a pair of annular seal grooves that are formed at the connection ends of the flow path holes of both fluid devices and into which each seal portion of the gasket is in close contact, and a clamp that fastens the opposing ends of both fluid devices together with each seal portion in close contact with the pair of seal grooves, wherein the gasket has an annular gasket body with an inner surface that contacts the transport fluid, and the clamp is arranged to cover the gasket body from the radial outside to fasten the ends together and has a through hole that penetrates radially.

[0011] The flow path joint structure of the present disclosure provides the same effects as the gasket. Furthermore, by inserting a ground wire or the like into the through-hole of the clamp that covers the gasket body, the gasket body can be electrically connected to the ground wire or the like. This allows the charge discharged from the transport fluid to the gasket body to escape from the ground outlet to the outside of the clamp.

[0012] (5) In the flow path joint structure of (4), it is preferable that the gasket further includes a grounding portion extending radially outward from the gasket body and inserted into the through-hole of the clamp, and the grounding portion has an exposed portion exposed radially outward from the through-hole of the clamp. In this case, the exposed portion of the grounding portion of the gasket is exposed radially outward from the through-hole of the clamp, so that electric charges discharged from the transport fluid to the gasket body can be easily released to ground through the exposed portion of the grounding portion.

[0013] According to the present disclosure, it is possible to discharge the electric charge on the transfer fluid while suppressing a decrease in the replaceability of the transfer fluid.

[0014] 13 is a perspective view showing a flow path joint structure according to a first embodiment of the present disclosure. FIG. 14 is a cross-sectional view of the flow path joint structure. FIG. 15 is a perspective view showing a gasket. FIG. 16 is a cross-sectional view showing the periphery of the gasket. FIG. 17 is a perspective view showing a clamp. FIG. 18 is a perspective view showing a first modified example of the gasket. FIG. 19 is a perspective view showing a second modified example of the gasket. FIG. 19 is a perspective view showing a modified example of the earth take-out portion of the gasket. FIG. 20 is a perspective view showing another modified example of the earth take-out portion of the gasket. FIG. 21 is a perspective view showing a modified example of the earth connection from the earth take-out portion of the gasket to the ground. FIG. 22 is a perspective view showing a modified example of the earth connection from the earth take-out portion of the gasket to the ground. FIG. 23 is a cross-sectional view showing the periphery of the gasket. FIG. 24 is a cross-sectional view showing a flow path joint structure according to a second embodiment of the present disclosure.

[0015] Next, preferred embodiments of the present disclosure will be described with reference to the accompanying drawings. [First Embodiment] <Flow Channel Joint Structure> Fig. 1 is a perspective view showing a flow channel joint structure 10 according to a first embodiment of the present disclosure. Fig. 2 is a cross-sectional view of the flow channel joint structure 10. The flow channel joint structure 10 of this embodiment is used to connect flow channel holes 50a formed in two fluidic devices 50, 50, respectively, in a piping path through which a chemical solution used in a semiconductor manufacturing device flows as a transport fluid. Each fluidic device 50 includes a pump, a valve, an accumulator, a filter, a flow meter, a pressure sensor, a joint, a piping block, or the like. Each fluidic device 50 of this embodiment is, for example, a joint that connects tubes.

[0016] 1 and 2 , the flow path joint structure 10 includes a primary seal groove (seal groove) 11 and a secondary seal groove 12 formed in each fluid device 50, a gasket 20, and a clamp 30. Hereinafter, in this specification, the term "axial direction" refers to the direction along the axis X of the gasket 20. Also, in this specification, the term "radial direction" refers to the direction perpendicular to the axis X of the gasket 20, and the term "circumferential direction" refers to the direction around the axis X of the gasket 20. Also, in this specification, the direction from the axial center of the gasket 20 toward both axial sides is referred to as the axial outward direction, and the direction from both axial sides of the gasket 20 toward the axial center is referred to as the axial inward direction.

[0017] The primary seal groove 11 is an annular tapered groove cut out so as to gradually increase in diameter from the axial inner end toward the axial outer end, radially outward of the connection end of the flow path hole 50a in each fluid device 50. The secondary seal groove 12 is formed in a cylindrical shape radially outward of the primary seal groove 11 in each fluid device 50.

[0018] <Gasket> Fig. 3 is a perspective view showing the gasket 20. In Figs. 2 and 3, the gasket 20 is made of a conductive material. The gasket 20 of this embodiment is made of, for example, a conductive carbon-containing fluororesin. The gasket 20 includes a gasket body 21 formed in an annular shape and a grounding portion 25 provided on the gasket body 21.

[0019] The gasket body 21 seals and connects the flow path holes 50a, 50a of both fluid devices 50, 50. The inner circumferential space of the gasket body 21 is formed as a circulation hole 21a through which the transfer fluid flows. The circulation hole 21a is in communication with the flow path holes 50a of each fluid device 50. Therefore, the gasket body 21 has an inner circumferential surface 21b that is disposed between the flow path holes 50a, 50a and comes into contact with the transfer fluid. The inner diameter of the circulation hole 21a of the gasket body 21 is approximately the same as the inner diameter of the flow path hole 50a.

[0020] Fig. 4 is a cross-sectional view showing the periphery of the gasket 20. In Fig. 3 and Fig. 4, the gasket body 21 has a main body portion 22 formed in its axial center, and a pair of primary seal portions (seal portions) 23 and a pair of secondary seal portions 24 provided on both axial sides of the main body portion 22. The main body portion 22 is disposed between the opposing ends of both fluid devices 50, 50.

[0021] The primary seal portion 23 protrudes axially outward from the radially inner side of both axial ends of the main body portion 22. The primary seal portion 23 is formed in an annular shape. The outer peripheral surface of the primary seal portion 23 gradually reduces in diameter from the axially inner end to the axially outer end. The primary seal portion 23 is inserted into the primary seal groove 11 of the fluid device 50 and is tightly fitted thereto.

[0022] The secondary seal portions 24 protrude axially outward from the radially outer sides of both axial end portions of the main body 22. The secondary seal portions 24 are formed in a cylindrical shape. The secondary seal portions 24 are press-fitted into the secondary seal grooves 12 of the fluidic device 50. The primary seal portions 23 and secondary seal portions 24 of the gasket main body 21 ensure the sealing performance of the portions connecting the flow path holes 50a, 50a of the two fluidic devices 50, 50.

[0023] The earth extraction portion 25 is provided at a predetermined circumferential position on the outer peripheral surface of the main body portion 22 of the gasket body 21 and extends radially outward from the outer peripheral surface. The earth extraction portion 25 is formed in a shape that allows it to be inserted into a through hole 35 (described below) of the clamp 30. In this embodiment, the earth extraction portion 25 is formed, for example, in the shape of a rectangular rod. The radial length of the earth extraction portion 25 is the length that protrudes radially outward from the clamp 30. Therefore, the earth extraction portion 25 has an exposed portion 25a that is exposed radially outward from the through hole 35 of the clamp 30. A mounting hole 25b that penetrates in the axial direction is formed in the exposed portion 25a of the earth extraction portion 25. In this embodiment, the earth extraction portion 25 is provided integrally with the gasket body 21, but it may also be provided separately from the gasket body 21.

[0024] 1 and 4 , the shank 41a of the bolt 41 is inserted into the mounting hole 25b of the exposed portion 25a from one axial side (the right side in FIG. 4 ). The tip of the shank 41a passes through the mounting hole 25b and protrudes from the other axial side (the left side in FIG. 4 ) of the exposed portion 25a. A connection terminal 40a, which is one end of the ground wire 40, is sandwiched between the head 41b of the bolt 41 and the exposed portion 25a. In this state, a nut 42 is tightened onto the tip of the shank 41a of the bolt 41. This fixes the connection terminal 40a of the ground wire 40 to the exposed portion 25a of the ground extraction portion 25, and the gasket 20 is electrically connected to the ground wire 40. The other end of the ground wire 40 is grounded.

[0025] <Clamp> Figure 5 is a perspective view showing the clamp 30. In Figures 2 and 5, the clamp 30 is a member that fastens the opposing ends of the two fluidic devices 50, 50 together with the primary seal portions 23 of the gasket 20 in close contact with the primary seal grooves 11 of the two fluidic devices 50. The clamp 30 of this embodiment fastens the flanges 50b, 50b formed on the ends of the two fluidic devices 50, 50 together by clamping them from both axially outer sides.

[0026] The clamp 30 has a first clamp portion 31 and a second clamp portion 32. The first clamp portion 31 and the second clamp portion 32 are formed in a semicircular arc shape when viewed in the axial direction. The first clamp portion 31 has a first fitting groove 31a that is formed in a substantially C-shape when viewed in cross section. Similarly, the second clamp portion 32 has a second fitting groove 32a that is formed in a substantially C-shape when viewed in cross section. Both the first fitting groove 31a and the second fitting groove 32a open radially inward.

[0027] One circumferential end of the second clamping portion 32 is connected to one circumferential end of the first clamping portion 31 so as to be rotatable about an axis C extending in the axial direction. The other circumferential ends of the first clamping portion 31 and the second clamping portion 32 are formed with a first end surface 31b and a second end surface 32b that abut against each other.

[0028] The second clamp portion 32 is rotatable between a closed position ( FIG. 5 ) and an open position (not shown) relative to the first clamp portion 31. The closed position is a position where the second end surface 32 b of the second clamp portion 32 abuts against the first end surface 31 b of the first clamp portion 31. The open position is a position where the second clamp portion 32 in the closed position has been rotated approximately 180 degrees counterclockwise in FIG. 5 around the axis C relative to the first clamp portion 31.

[0029] When the second clamp portion 32 is in the open position, the first clamp portion 31 covers the circumferential halves of both flanges 50b and the gasket body 21 from the radially outward direction. At this time, these halves of both flanges 50b are fitted into the first fitting grooves 31a. When the second clamp portion 32 is rotated from this state to the closed position, the second clamp portion 32 covers the circumferential halves of both flanges 50b and the gasket body 21 from the radially outward direction. At this time, these halves of both flanges 50b are fitted into the second fitting grooves 32a. As described above, the clamp 30 is positioned so as to cover both flanges 50b and the gasket body 21 from the radially outward direction.

[0030] An engagement groove 33 is integrally formed on the other circumferential end of the first clamp portion 31. An engagement portion 34 that can engage with the engagement groove 33 is integrally formed on the other circumferential end of the second clamp portion 32. When the second clamp portion 32 is in the closed position, the engagement groove 33 of the first clamp portion 31 engages with the engagement portion 34 of the second clamp portion 32. This fastens the flanges 50b, 50b of both fluid devices 50, 50 together.

[0031] The engagement groove 33 may be provided separately from the first clamp portion 31. The engagement portion 34 may be provided separately from the second clamp portion 32. Alternatively, the engagement groove 33 may be provided in the second clamp portion 32, and the engagement portion 34 may be provided in the first clamp portion 31.

[0032] The first clamp portion 31 has a through hole 35 formed radially penetrating through its circumferential middle portion. The ground lead portion 25 of the gasket 20 is inserted into the through hole 35 of the first clamp portion 31. Specifically, as described above, when half of the circumference of each of the flanges 50 b, 50 b and the gasket body 21 is covered from the radial outside by the first clamp portion 31, the ground lead portion 25 is inserted into the through hole 35 of the first clamp portion 31. The through hole 35 may be formed in the second clamp portion 32.

[0033] With the above configuration, when the transfer fluid flowing through the flow holes 21a of the gasket body 21 comes into contact with the inner peripheral surface 21b of the gasket body 21, the electric charge stored in the transfer fluid is discharged to the gasket body 21. The electric charge discharged to the gasket body 21 is conducted from the gasket body 21 to the exposed portion 25a of the earth extraction portion 25 and escapes to the ground via the earth wire 40.

[0034] <Effects> According to the flow path joint structure 10 of the first embodiment, when the transfer fluid comes into contact with the inner circumferential surface 21b of the gasket 20 made of a conductive material, the electric charge stored in the transfer fluid can be discharged to the gasket 20. In addition, a pair of primary seal portions 23 provided on both axial sides of the gasket 20 are tightly fitted to the primary seal grooves 11 formed at the connection ends of the flow path holes 50a of each fluid device 50. This makes it possible to prevent the transfer fluid from accumulating at the connection portions between each fluid device 50 and the gasket 20. As a result, it is possible to prevent a decrease in the replaceability of the transfer fluid.

[0035] The ground lead-out portion 25 extending radially outward from the gasket body 21 is inserted into the through-hole 35 of the clamp 30. This allows the electric charge discharged from the transported fluid to the gasket body 21 to escape from the clamp 30 through the ground lead-out portion 25.

[0036] Since the exposed portion 25a of the grounding portion 25 is exposed radially outward from the clamp 30, electric charges discharged from the transported fluid to the gasket body 21 can be easily released to the ground from the exposed portion 25a of the grounding portion 25. This is particularly effective when the fluid device 50 and the tube are each made of a conductive material, as electric charges discharged from the transported fluid to the fluid device 50 and the tube can also be released to the ground via the flow path joint structure 10. In this case, it is preferable that at least one of the fluid device 50 and the tube be made of a transparent or translucent material so that the interior of the component can be visually confirmed.

[0037] <Modifications of Gasket> Fig. 6 is a perspective view showing a first modification of the gasket 20. As shown in Fig. 6, the gasket 20 of this modification includes ribs 26 provided on the inner circumferential surface 21b of the gasket body 21. The ribs 26 are components for increasing the contact area of ​​the gasket 20 with the transfer fluid. In other words, the ribs 26 are components that come into contact with the transfer fluid other than the inner circumferential surface 21b of the gasket body 21. The ribs 26 of this modification are provided integrally with the gasket body 21 and are formed in a cross shape centered on the axis X.

[0038] The rib 26 of this modified example has a first rib portion 26a, a second rib portion 26b, a third rib portion 26c, and a fourth rib portion 26d that extend in the directions of 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock, respectively, from the axis X. The first to fourth rib portions 26a to 26d are connected to one another on the axis X. The radial outer ends of the first to fourth rib portions 26a to 26d are fixed to the inner circumferential surface 21b of the gasket body 21.

[0039] Each of the first to fourth rib portions 26a to 26d is formed in a flat plate shape and is arranged so that the plate surface is parallel to the flow direction (axial direction) of the transported fluid. This prevents the flow of the transported fluid from being obstructed by the rib 26. The axial length of each of the first to fourth rib portions 26a to 26d is equal to or less than the axial length of the inner circumferential surface 21b of the gasket body 21.

[0040] 7 is a perspective view showing a second modified example of the gasket 20. As shown in FIG. 7, the gasket 20 of this modified example is similar to the first modified example in that it includes a cross-shaped rib 26. The axial length of each of the first to fourth rib portions 26a to 26d of the rib 26 of this modified example is greater than the axial length of the inner circumferential surface 21b of the gasket body 21. Both axial ends of each of the first to fourth rib portions 26a to 26d protrude axially outward beyond the secondary seal portion 24 of the gasket body 21.

[0041] According to the gasket 20 of the first modified example (Figure 6) and the second modified example (Figure 7), the transport fluid comes into contact with the ribs 26 in addition to the inner surface 21b of the gasket body 21, so that the electric charge stored in the transport fluid can be efficiently discharged to the gasket 20.

[0042] The ribs 26 of the first and second modified examples are not limited to a cross shape and may have other shapes, such as a lattice shape. Furthermore, the ribs 26 of the first and second modified examples may be formed of at least one member. In this case, the ribs 26 may simply protrude radially inward from the inner circumferential surface 21 b of the gasket body 21.

[0043] Instead of the mounting hole 25b, the exposed portion 25a of the earth extraction portion 25 may be formed with a mounting groove 25c that opens to the upper side in the figure as shown in Figure 8, or with a mounting groove 25d that opens to the left side in the figure as shown in Figure 9.

[0044] 10 and 11 are perspective views showing a modified example of the earth connection from the earth outlet 25 of the gasket 20 to the ground. As shown in Fig. 10, this modified example of the earth connection is used when the clamp 30 fastening both fluid devices 50, 50 is fixed to the wall surface of the housing 46 via a fixing member 45. The fixing member 45 and the housing 46 are made of a conductive material. The housing 46 is earth-connected to the ground.

[0045] The fixing member 45 has a U-shaped fixing body 45a and flanges 45b provided on both ends of the fixing body 45a. The fixing body 45a covers the first clamp portion 31 of the clamp 30 from the radially outward side. The fixing body 45a has an opening 45c for exposing the through-hole 35 while covering the first clamp portion 31. The fixing body 45a also has a screw hole 45d formed axially adjacent to the opening 45c. The flanges 45b are fixed in contact with the wall surface of the housing 46 by bolts 47.

[0046] The ground lead-out portion 25 of the gasket 20 is flexible. The shaft 48a of the bolt 48 is inserted into the mounting hole 25b of the exposed portion 25a of the ground lead-out portion 25 from one axial side (the right side in FIG. 10 ). The tip of the shaft 48a passes through the mounting hole 25b and protrudes from the other axial side of the exposed portion 25a (the left side in FIG. 10 ). From this state, the exposed portion 25a of the ground lead-out portion 25 is bent to the other axial side, as shown in FIG. 11 .

[0047] After the exposed portion 25a is bent, the shaft 48a of the bolt 48 that has passed through the mounting hole 25b is screwed into the threaded hole 45d of the fixing body 45a. When the shaft 48a of the bolt 48 is screwed into the threaded hole 45d, the exposed portion 25a of the earth extraction portion 25 is fixed in a sandwiched state between the head 48b of the bolt 48 and the fixing body 45a of the fixing member 45. In this way, the gasket 20 is electrically connected to the fixing member 45.

[0048] With the above configuration, the electric charge discharged from the transport fluid to the gasket body 21 (see Figure 4) is guided from the gasket body 21 to the exposed portion 25a of the earth extraction portion 25, and then escapes to ground via the fixing member 45 and the housing 46.

[0049] The screw hole 45d of the fixing member 45 is not limited to this modified example. For example, a part of the outer periphery of the fixing body 45a may be made to protrude radially outward in parallel with the exposed portion 25a of the ground extraction portion 25, and the screw hole 45d extending in the axial direction may be formed in the protruding part. In this case, the shaft portion 48a of the bolt 48 can be tightened into the screw hole 45d without bending the exposed portion 25a.

[0050] <Modification of Clamp> Figure 12 is a perspective view showing a modification of the clamp 30. As shown in Figure 12, the clamp 30 of this modification has a through hole 36 formed by both the first clamp portion 31 and the second clamp portion 32. A first groove 36a that forms part of the through hole 36 is formed at the other circumferential end of the first clamp portion 31. A second groove 36b that forms the other part of the through hole 36 is formed at the other circumferential end of the second clamp portion 32. When the first clamp portion 31 is in the closed position, the first groove 36a and the second groove 36b face each other and communicate with each other, thereby forming a single through hole 36.

[0051] In this modification, when the first clamp portion 31 covers the circumferential halves of both flanges 50b, 50b and the gasket body 21 from the radially outward direction, a part of the ground extraction portion 25 is inserted into the first groove 36a of the first clamp portion 31. When the second clamp portion 32 is rotated from this state to the closed position, the other part of the ground extraction portion 25 is inserted into the second groove 36b of the second clamp portion 32. As a result, the ground extraction portion 25 is inserted into the through-hole 36 of the clamp 30.

[0052] <Another Use Example of the Gasket> Fig. 13 is a perspective view showing another use example of the gasket 20. Fig. 14 is a cross-sectional view showing the periphery of the gasket 20 in Fig. 13. Figs. 13 and 14 show a use example in which flow path holes 60a, 60a formed in two block-shaped fluidic devices 60, 60 are connected to each other by the gasket 20 of the first embodiment.

[0053] 13 and 14, each of the fluid devices 60 has opposing surfaces 60b that are adjacent to each other and face each other. An annular first arrangement groove 60c is formed in each of the opposing surfaces 60b, in which the main body 22 of the gasket 20 is disposed. Furthermore, a second arrangement groove 60d is formed in each of the opposing surfaces 60b, in which a portion of the ground connection portion 25 of the gasket 20 (excluding the exposed portion 25a) is disposed. The first arrangement groove 60c and the second arrangement groove 60d on each opposing surface 60b are connected to each other.

[0054] A primary seal groove 61 and a secondary seal groove 62 are formed in the first arrangement groove 60c of each opposing surface 60b. The primary seal groove 61 and the secondary seal groove 62 have the same configuration as the primary seal groove 11 and the secondary seal groove 12 of the first embodiment, and therefore detailed description will be omitted. A pair of primary seal portions 23 of the gasket 20 are inserted into and tightly fitted into the primary seal groove 61 of each fluid device 60. A pair of secondary seal portions 24 of the gasket 20 are press-fitted into the secondary seal groove 62 of each fluid device 60. The primary seal portions 23 and secondary seal portions 24 of the gasket 20 ensure sealing performance in the portion connecting the flow path holes 60a, 60a in both fluid devices 60, 60.

[0055] As described above, the primary seal portion 23 and the secondary seal portion 24 are tightly fitted and press-fit into the primary seal groove 61 and the secondary seal groove 62, respectively, so that the main body portion 22 and a portion of the ground lead portion 25 are respectively positioned in the first arrangement groove 60c and the second arrangement groove 60d of each opposing surface 60b. As a result, the exposed portion 25a of the ground lead portion 25 is exposed to the outside of both fluid devices 60, 60 (the right side in FIG. 15 ). The connection terminal 40a of the ground wire 40 is fixed to the exposed portion 25a of the ground lead portion 25, and the gasket 20 is electrically connected to the ground wire 40. The fixing structure is the same as in the first embodiment, so a detailed description thereof will be omitted. As a result, the gasket 20 is electrically connected to the ground wire 40.

[0056] In this example, the exposed portion 25a of the earth extraction portion 25 of the gasket 20 is exposed to the outside of both fluid devices 60, 60. This allows the electric charge discharged from the transport fluid to the gasket body 21 to be easily released to the ground from the exposed portion 25a of the earth extraction portion 25 via the earth wire 40.

[0057] Second Embodiment Fig. 15 is a cross-sectional view showing a flow path joint structure 10 according to a second embodiment of the present disclosure. The flow path joint structure 10 of this embodiment differs from the first embodiment in the connection structure of the ground wire 40 to the gasket 20. The gasket 20 of this embodiment includes only the gasket body 21 and does not include the ground lead-out portion 25 (see Fig. 4). A threaded hole 27 is formed at a predetermined position in the circumferential direction on the outer peripheral surface of the main body portion 22 of the gasket body 21. The inner diameter of the through hole 35 of the clamp 30 is set to a size that allows the screw (bolt) 43 and the connection terminal 40a of the ground wire 40 to be inserted therein.

[0058] The screw 43, with the connection terminal 40a of the ground wire 40 hooked onto its head 43b, is inserted into the through-hole 35 of the clamp 30 together with the connection terminal 40a. The shank 43a of the screw 43 inserted into the through-hole 35 of the clamp 30 is screwed into the threaded hole 27 of the gasket body 21. At this time, the connection terminal 40a of the ground wire 40 is sandwiched between the head 43b of the screw 43 and the outer peripheral surface of the gasket body 21 (main body portion 22). Therefore, by screwing the shank 43a of the screw 43 into the threaded hole 27, the connection terminal 40a of the ground wire 40 is fixed to the main body portion 22 of the gasket body 21. As a result, the ground wire 40 is electrically connected to the gasket 20. Other configurations of this embodiment are similar to those of the first embodiment, and therefore the same reference numerals are used and their description will be omitted.

[0059] According to the flow path joint structure 10 of the second embodiment, as in the first embodiment, electric charges stored in the transfer fluid can be discharged to the gasket 20, and a decrease in the replaceability of the transfer fluid can be suppressed. Furthermore, a connection terminal 40a of a ground wire 40 and a screw 43 are inserted into the through hole 35 of the clamp 30 covering the gasket body 21, and the shank 43a of the screw 43 is fastened into the threaded hole 27 of the gasket body 21. This electrically connects the ground wire 40 to the gasket body 21, so that electric charges discharged from the transfer fluid to the gasket body 21 can be released to the outside of the clamp 30 by the ground wire 40.

[0060] [Others] The above-disclosed embodiments are illustrative in all respects and are not limiting. For example, the flow path joint structure 10 and the gasket 20 of the above-described embodiments may be applied to fields other than semiconductor manufacturing equipment, such as liquid crystal / organic electroluminescence (EL) fields, medical / pharmaceutical fields, and automotive-related fields. In the above-described embodiments, the bolt 41 (43) is used to secure the connection terminal 40a of the ground wire 40 to the ground outlet 25 of the gasket 20, but other securing means may also be used.

[0061] The gasket 20 may be applied to a flow path joint structure in which the ends of both fluid devices 50, 50 are fastened together by a fastening means other than the clamp 30. The conductive material of the gasket 20 is not limited to carbon-containing fluororesin, and may be, for example, metal. The gasket 20 includes a primary seal portion 23 and a secondary seal portion 24, but it is sufficient that it includes at least the primary seal portion 23. In that case, it is sufficient that the flow path joint structure 10 includes at least the primary seal groove 11 of the primary seal groove 11 and secondary seal groove 12.

[0062] REFERENCE SIGNS LIST 10 Flow path joint structure 11 Primary seal groove (seal groove) 20 Gasket 21 Gasket body 21b Inner peripheral surface 23 Primary seal portion (seal portion) 25 Earth extraction portion 25a Exposed portion 26 Rib 30 Clamp 35, 36 Through hole 50, 60 Fluid device 50a, 60a Flow path hole

Claims

1. A gasket that seals and connects flow path holes formed in two fluid devices, the gasket being made of a conductive material and having an inner surface that is positioned between the flow path holes and comes into contact with the transported fluid, and a pair of annular seal portions that are provided on both axial sides and that fit tightly into annular seal grooves formed at the connecting ends of the flow path holes of both fluid devices.

2. The gasket according to claim 1, further comprising a rib provided on the inner peripheral surface and in contact with the transported fluid.

3. A gasket according to claim 1 or claim 2, further comprising: an annular gasket body having the inner peripheral surface; and an earth extraction portion extending radially outward from the gasket body.

4. A flow path joint structure comprising: a gasket as claimed in claim 1 or claim 2 that seals and connects flow path holes formed in two fluid devices; a pair of annular seal grooves formed at the connecting ends of the flow path holes of the two fluid devices, with each seal portion of the gasket tightly fitting; and a clamp that fastens the opposing ends of the two fluid devices together with each seal portion tightly fitting in the pair of seal grooves, wherein the gasket has an annular gasket body having an inner surface that comes into contact with the transport fluid, and the clamp is arranged to cover the gasket body from the radial outside in order to fasten the ends together, and has a through hole that passes through in the radial direction.

5. A flow path joint structure as described in claim 4, wherein the gasket further comprises an earth extraction portion extending radially outward from the gasket body and inserted into the through hole of the clamp, and the earth extraction portion has an exposed portion exposed radially outward from the through hole of the clamp.

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