Positioning member and pipe connection structure

Abstract

To provide a technology which positions a gasket attached to a space between a flange of a pipe and a fluid device with a positioning member which positions the fluid device relative to the pipe.SOLUTION: Positioning members 50 according to an embodiment are attached to a pair of through holes 71 of a flange 90F of a pipe 90, and large diameter parts 52 protruding from the flange 90F support a sleeve side flange 12F of a housing 11 from below and contact with the sleeve side flange at two points to match a center axis J2 of the flange 90F with a center axis J1 of the sleeve side flange 12F. Then, a gasket 60 disposed between the flange 90F and the sleeve side flange 12F is received in cutout parts 55 of the positioning members 50. The gasket 60 is supported from below by bolts 70 exposed from the cutout parts 55 and placed in contact with the bolts at two points to match a center axis of the gasket 60 with the center axis J2 of the flange 90F.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a structure of a positioning member and a pipe connection section that are used in a pipe connection section between a pair of flanges midway along a pipe and a fluid device, and that positions the fluid device relative to the pipe. [Background technology]

[0002] BACKGROUND ART A conventional positioning member is known that is attached to a plurality of fastening members that are placed across a pair of flanges of a pipe (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 4-50726 (Page 2, bottom left column, line 14 to bottom right column, line 14, Figures 1 and 2) Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional positioning members have the problem that it is difficult to position the gasket that is attached between the flange and the fluid device, and a solution to this problem is required. [Means for solving the problem]

[0005] The invention of claim 1, made to achieve the above-mentioned object, is a positioning member used in a piping connection section in which a fluid device is sandwiched between a pair of flanges in the middle of a piping via a pair of gaskets, and a plurality of fastening members are passed through a plurality of through holes in the pair of flanges and spanned between the pair of flanges, the positioning member being tubular and passed outside the fastening members, one end of which is fitted into a pair of through holes in each of the flanges and protruding from each of the flanges, and positioning the fluid device relative to the piping by contacting each end of the fluid device at two points, and the positioning member has a cutout portion that exposes the fastening members on the gasket side, so that each gasket is positioned relative to the piping by contacting the fastening members at two points. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a front view of a flow meter according to an embodiment of the present disclosure. [Figure 2] Section AA of the housing in Figure 1 [Figure 3] Exploded perspective view of the piping connection [Figure 4] (A) is a perspective view of the positioning member, (B) is a cross-sectional view, and (C) is a cross-sectional view taken along the line CC in FIG. 4(B). [Figure 5] Cross section of pipe connection shown in Figure 1 [Figure 6] DD cross section of Figure 5 of the piping connection [Figure 7] A diagram showing the gasket abutting on the bolt exposed from the notch in the positioning member [Figure 8] A diagram showing the housing abutting against the large outer diameter portion of the positioning member [Figure 9] A diagram showing a gasket attached to a positioning member that does not have a notch [Figure 10] (A) and (B) Positioning members according to other embodiments DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, with reference to FIGS. 1 to 9, an embodiment of a flowmeter 10 having a pipe connection portion 20 of the present disclosure will be described. The flowmeter 10 of this embodiment is a flange clamp type flowmeter and, as shown in FIG. 1, has a housing 11 installed between a pair of annular flanges 90F provided midway through a pipe 90. The housing 11 is, for example, a casting, has a cylindrical shape, extends laterally, and both end faces thereof abut against a pair of flanges 90F via a pair of gaskets 60 (see FIG. 1). The housing 11 connects the divided pipes 90 so that a fluid (e.g., water in this embodiment) flowing through the pipes 90 flows through a measurement flow path 13 that penetrates the housing 11 (see FIG. 2). The pipes 90 are horizontal pipes and are omitted from the drawings other than FIG. 1.

[0008] The flowmeter 10 also includes a display case 40 (see FIG. 1). The display case 40 houses a circuit board, a display unit, and the like (not shown), and the circuit board calculates the flow rate of the fluid, and the display unit displays the calculated flow rate, etc., so that it can be seen from the outside. The display case 40 is connected to the housing 11 by a cylindrical relay member 30.

[0009] Pipe connection portion 20, which is a connection portion between a pair of flanges 90F of pipe 90 and housing 11 of the flowmeter, positions housing 11 with respect to flanges 90F (piping 90) by positioning member 50. The configuration of pipe connection portion 20 will be described below.

[0010] As shown in Fig. 3, the flange 90F has four through holes 71, through which the bolts 70 are passed, formed at equal intervals on a circumference concentric with the central axis of the flange 90F. The housing 11 is placed inside the four bolts 70 extending between the pair of flanges 90F, and is fastened by nuts 72 threaded onto the bolts 70 (see Fig. 1). Hereinafter, the central axis of the flange 90F (the central axis of the piping 90) will be referred to as the central axis J2. The bolts 70 have threads (not shown) threaded onto the nuts 72 on the entire outer circumferential surface. The bolts 70 in this embodiment correspond to the "fastening member" in the claims, but the fastening member is not limited to the bolts 70.

[0011] Circular openings 12K communicating with the measurement flow path 13 are formed on both end surfaces of the housing 11, and sleeve-side flanges 12F protrude laterally (see FIG. 3). The sleeve-side flange 12F is annular and concentric with the circular opening 12K, and four bolts 70 extending between the pair of flanges 90F clamp the outer edge of the sleeve-side flange 12F. Hereinafter, the central axis of the sleeve-side flange 12F will be referred to as the central axis J1 (see FIG. 2).

[0012] The outer diameter of the sleeve-side flange 12F is smaller than the distance from the central axis J2 of the flange 90F to the bolts 70 passed through the through-holes 71 (see FIG. 6). In other words, the outer diameter of the sleeve-side flange 12F is smaller than a circle inscribed in the four bolts 70 extending between the pair of flanges 90F. The circular opening 12K is smaller than the inner diameter of the flange 90F.

[0013] The gasket 60 described above is disposed between the sleeve-side flange 12F and the flange 90F. In this embodiment, the gasket 60 is an inner gasket whose outer edge is disposed inside the four bolts 70 that are inserted between the pair of flanges 90F. The outer diameter of the inner gasket is approximately the same as the diameter of a circle inscribed in the four bolts 70 that are inserted between the pair of flanges 90F, and the inner diameter is approximately the same as or slightly larger than the inner diameter of the flanges 90F (see FIG. 6). The gasket 60 is made of resin, rubber, or metal.

[0014] The positioning member 50 is a cylindrical resin injection molded product, and as shown in Figure 5, is attached to two adjacent through holes 71 out of the four through holes 71 of the flange 90F, with bolts 70 inserted inside.

[0015] Specifically, as shown in Figures 4(A) and (B), positioning member 50 has a stepped portion 53 formed in the axial middle portion that reduces the diameter of one end of the outer circumferential surface, with small outer diameter portion 51 located on one end side of stepped portion 53 and large outer diameter portion 52 located on the other end side of stepped portion 53. The small outer diameter portion 51 has an outer diameter that is approximately the same as or slightly smaller than the inner diameter of through hole 71, and is fitted into the inner surface of through hole 71 (see Figure 6). Hereinafter, in positioning member 50, the side where small outer diameter portion 51 is located will be referred to as the tip side, and the side where large outer diameter portion 52 is located will be referred to as the base side, as appropriate.

[0016] 5, the large outer diameter portion 52 protruding from the flange 90F abuts against the sleeve-side flange 12F at two points. The outer diameter of the large outer diameter portion 52 is set so that the distance from the center axis J2 of the flange 90F to the large outer diameter portion 52 is approximately the same as the outer diameter of the sleeve-side flange 12F (see FIG. 6). In other words, the outer diameter of the sleeve-side flange 12F is approximately the same diameter as a circle inscribed in the large outer diameter portion 52 of the positioning member 50 attached to the flange 90F. In this embodiment, the axial length of the large outer diameter portion 52 is shorter than the thickness of the sleeve-side flange 12F, but is not limited to this and may be longer than the thickness of the sleeve-side flange 12F.

[0017] As shown in FIGS. 4A and 4B, the positioning member 50 is formed with a notch 55 that exposes the inserted bolt 70. The notch 55 is disposed so as to straddle the step 53 in the axial direction and extends 180 degrees in the circumferential direction (see FIG. 4C). As shown in FIG. 6, the gasket 60 is received in the portion of the notch 55 formed in the large outer diameter portion 52, and the gasket 60 abuts at two points against the bolt 70 exposed from the notch 55. In this embodiment, the distance from the step 53 to the end face on the base end side of the notch 55, i.e., the axial width of the portion of the notch 55 formed in the large outer diameter portion 52, is approximately the same as or slightly larger than the thickness of the gasket 60.

[0018] As shown in Figures 4(A) and (B), press-fit protrusions 54 are formed on the outer peripheral surface of the small outer diameter portion 51, extending axially from a position adjacent to the stepped portion 53 to a position near the tip. As shown in Figure 4(C), the press-fit protrusions 54 have a semicircular cross section, and four press-fit protrusions 54 are provided at equal intervals in the circumferential direction. The axial tip side of each press-fit protrusion 54 forms an inclined portion 54S that gradually approaches the outer peripheral surface of the small outer diameter portion 53 (see Figure 4(B)). The four press-fit protrusions 54 are arranged symmetrically with respect to a line connecting the boundary between the portion of the small outer diameter portion 51 in the circumferential direction where the notched portion 55 is formed and the portion where the notched portion 55 is not formed (see Figure 4(C)).

[0019] This completes the description of the configuration of this embodiment. Next, a method for assembling the pipe connection portion 20 will be described with reference to Figures 7 and 8. In this embodiment, the pair of flanges 90F of the pipe 90 are placed on a horizontal placement surface, for example, so that the four through holes 71 are aligned horizontally in pairs above and below (see Figure 7).

[0020] First, as shown in Fig. 7, the positioning members 50 are attached to a pair of through holes 71 arranged horizontally at the bottom of the through holes 71 of each flange 90F. Specifically, the small outer diameter portion 51 is pushed into the through hole 71 until the stepped portion 53 of the positioning member 50 abuts against the flange 90F (see Fig. 6). At this time, the press-fit protrusion 54 provided on the small outer diameter portion 51 abuts against the inner surface of the through hole 71 and is crushed. After attachment, the position of the positioning member 50 is adjusted so that the notch 55 faces the center of the flange 90F.

[0021] Next, the bolt 70 is passed through the through-hole 71 to which the positioning member 50 is attached, and is extended between the pair of flanges 90F.

[0022] Next, the gasket 60 is placed in the notch 55 of the positioning member 50. At this time, the gasket 60 is positioned so that its outer edge abuts against the bolt 70 exposed from the notch 55. As a result, the gasket 60 abuts against the bolt 70 at two points and is supported from below.

[0023] 8, the housing 11 is placed between the pair of flanges 90F with the connected display case 40 positioned above, and the pair of sleeve-side flanges 12F of the housing 11 are brought into contact with the large outer diameter portions 52 of the positioning members 50. As a result, the pair of sleeve-side flanges 12F come into contact with the positioning members 50 at two points and are supported from below.

[0024] Then, the bolts 70 are passed through the two upper through-holes 71 of the flange 90F. Finally, nuts 72 are screwed into both ends of each bolt 70 and tightened to fix the housing 11 between the pair of flanges 90F, completing the assembly (see FIG. 1).

[0025] As described above, in the pipe connection portion 20 of this embodiment, the housing 11 of the flowmeter 10 is sandwiched between a pair of flanges 90F of the pipe 90 and fastened by four bolts 70 that are inserted between the pair of flanges 90F. In this embodiment, the positioning member 50 is attached to two of the through holes 71 of the flange 90F that are arranged side by side at the bottom of the through holes 71 of the flange 90F that is placed on a horizontal mounting surface, and the sleeve-side flange 12F of the housing 11 is abutted at two points against the large outer diameter portion 52 of the positioning member 50 that protrudes from the flange 90F. As a result, the gap between the outer diameter of the sleeve-side flange 12F and the circle inscribed in the bolts 70 that are inserted between the pair of flanges 90F is filled by the thickness of the large outer diameter portion 52 of the positioning member 50, and the central axis J2 of the flange 90F and the central axis J1 of the sleeve-side flange 12F can be aligned to position the housing 11 with respect to the pipe 90. Furthermore, since the sleeve-side flange 12F is supported from below by the large outer diameter portion 52, assembly can be performed stably.

[0026] Furthermore, according to the positioning member 50 of this embodiment, even if the outer diameters of the flange 90F or the sleeve side flange 12F are changed, the thickness of the large outer diameter portion 52 of the positioning member 50 can be appropriately changed to match these outer diameters, thereby easily aligning the center axis J2 of the flange 90F with the center axis J1 of the sleeve side flange 12F.

[0027] Furthermore, in this embodiment, the positioning member 50 is provided with a notch 55 that receives the gasket 60. This allows the gasket 60 to be temporarily fixed to the flange 90F before the housing 11 is installed between the pair of flanges 90F. This makes it possible to check whether the gasket 60 is misaligned with respect to the flange 90F before assembling the flange 90F and the housing 11. Also, in this embodiment, the distance from the stepped portion 53 of the notch 55 to the end face on the base end side, i.e., the axial width of the portion of the notch 55 formed in the large outer diameter portion 52, is approximately the same as or slightly larger than the thickness of the gasket 60. If the distance from the stepped portion 53 of the notch 55 to the end face on the base end side is larger than the thickness of the gasket 60, the gasket 60 can be more easily received in the notch 55, thereby reducing the effort required to install the gasket 60. Furthermore, if the distance from the step portion 53 to the end face on the base end side of the cutout portion 55 is made approximately the same as the thickness of the gasket 60, the gasket 60 will be clamped between the end face on the base end side of the cutout portion 55 and the flange 90F, making it less likely to fall out from within the cutout portion 55, and the housing 11 can be easily assembled to the piping 90.

[0028] Furthermore, the gasket 60 abuts at two points against the bolts 70 exposed from the cutouts 55. Here, the outer diameter of the gasket 60, which is the inner gasket, is approximately the same diameter as a circle inscribed in the four bolts 70 that are inserted between the pair of flanges 90F, so that by abutting the gasket 60 against the bolts 70, the central axis of the gasket 60 can be easily aligned with the central axis J2 of the flanges 90F. Furthermore, because the gasket 60 is supported from below by the bolts 70, assembly can be performed stably.

[0029] Here, we will explain the case where a positioning member 80 that does not have a notch 55 is attached. In the case of this positioning member 80, if it is a full-surface gasket with bolt holes, it will not be misaligned with the flange 90F. However, if it is an inner gasket whose outer edge is placed inside the bolt 70 that spans between a pair of flanges 90F, like the gasket 60 of this embodiment, the gasket 60 will come into contact with the large outer diameter portion 52 of the positioning member 50, as shown in Fig. 9, and the central axis J3 of the gasket 60 will be misaligned from the central axis J2 of the flange 90F.

[0030] In contrast, with the positioning member 50 of this embodiment, as described above, the notch 55 of the positioning member 50 allows the gasket 60 to abut against the bolt 70, so that the central axis of the gasket 60 can be easily aligned with the central axis J2 of the flange 90F. In other words, the positioning member 50, which is used to position the housing 11 relative to the piping 90, can also easily position the gasket 60.

[0031] Furthermore, in this embodiment, a step portion 53 is provided on the outer peripheral surface of the positioning member 50, and a large outer diameter portion 52, which is larger in diameter than the small outer diameter portion 51 that fits into the through hole 71 of the flange 90F, protrudes from the flange 90F. This allows the positioning member 50 to be positioned relative to the flange 90F in the insertion direction, making it easy to assemble the flange 90F and the housing 11.

[0032] Furthermore, since the outer surface of the small outer diameter portion 51 is provided with the press-fit protrusion 54 that comes into contact with the inner surface of the through hole 71 and is crushed, the positioning member 50 is less likely to fall out of the through hole 71, improving workability. Moreover, the press-fit protrusion 54 is provided from a position near the tip of the small outer diameter portion 51 to the base end, and the tip of the press-fit protrusion 54 has an inclined portion 54S, improving insertion into the through hole 71 and facilitating the fitting work.

[0033] [Other embodiments] (1) In the above embodiment, the distance from the stepped portion 53 to the base-side end face of the cutout 55, i.e., the axial width of the portion of the cutout 55 formed in the large outer diameter portion 52, was approximately the same as or slightly larger than the thickness of the gasket 60. However, it may be smaller. In this case, when inserting the small outer diameter portion 51 of the positioning member 50 into the through hole 71 of the flange 90F, the gasket 60 is received in the cutout 55 before the stepped portion 53 abuts against the flange 90F, and then the small outer diameter portion 51 is further inserted into the through hole 71, thereby sandwiching and fixing the gasket 60 between the base-side end face of the cutout 55 and the flange 90F. This makes it difficult for the gasket 60 to fall out of the cutout 55, facilitating assembly of the housing 11 to the piping 90.

[0034] (2) In the above embodiment, the notch 55 of the positioning member 50 was formed in the small outer diameter portion 51 and the large outer diameter portion 52, arranged so as to straddle the step portion 53 in the axial direction, but it may also be formed only in the large outer diameter portion 52.

[0035] (3) The positioning member 50 of the above embodiment includes the small outer diameter portion 51 that fits into the through hole 71 of the flange 90F. However, the small outer diameter portion 51 may not be included.

[0036] (4) In the above embodiment, the notch 55 of the positioning member 50 has a width extending over 180 degrees in the circumferential direction, but this is not limited to this as long as it is large enough to abut against the bolt 70 exposed from the notch 55.

[0037] (5) In the above embodiment, the positioning member 50 is provided with four press-fit protrusions 54 spaced equally apart in the circumferential direction, but the number may be four or more, or less than four. Also, in the above embodiment, the press-fit protrusions 54 are shaped to extend in the axial direction, but this is not limiting and the press-fit protrusions 54 may be, for example, protruding or annular. Furthermore, the press-fit protrusions 54 may not be provided.

[0038] (6) In the above embodiment, the positioning members 50 are attached to both the upstream and downstream sides of the flowmeter 10. However, they may be attached to only one of the upstream and downstream sides.

[0039] (7) In the above embodiment, a positioning member 50 was used in which the outer peripheral surface of the large outer diameter portion 52 had a generally flat cylindrical surface. However, to avoid a situation in which the large outer diameter portion 52 interferes with an external component attached to the flowmeter 10 or the outer surface of the housing 11, making it impossible to abut the sleeve-side flange 12F against the large outer diameter portion 52 at two points, a positioning member 50V having a stepped surface 56 that reduces the diameter on the base end side as shown in FIG. 10(A) or a positioning member 50W having a flat surface 57 in which part of the outer peripheral surface is cut flat as shown in FIG. 10(B) may be used.

[0040] (8) In the above embodiment, the positioning member 50 is made of resin, but it may be made of metal.

[0041] (9) In the above embodiment, the flange 90F is provided with four through holes 71, but it may be provided with eight through holes 71. In this case, when the flange 90F is placed on a horizontal surface, the positioning members 50 may be attached to the pair of through holes 71 located at the bottom or the pair of through holes 71 located second from the bottom.

[0042] (10) In the above embodiment, the bolt 70 is threaded on the entire outer periphery thereof, but it may be threaded only on both ends where the nut 72 is screwed.

[0043] (11) In the above embodiment, the flow meter 10 measures the flow rate of water as a fluid. However, the flow meter 10 may measure the flow rate of a liquid other than water or a gas.

[0044] (12) In the above embodiment, the housing 11 is a cast product, but it may be an injection-molded product made of resin.

[0045] (13) In the above embodiment, the piping 90 is horizontal piping, and the positioning member 50 is used at the piping connection portion 20 between the flange 90F placed on a horizontal mounting surface and the sleeve-side flange 12F. However, the positioning member 50 may be used for the flange 90F of a piping that extends in a direction intersecting the horizontal direction, or for the flange 90F of a vertical piping. In such a case, the sleeve-side flange 12F of the housing 11 and the gasket 60 cannot be supported from below during assembly. However, the sleeve-side flange 12F can be abutted against the large outer diameter portion 52 of the positioning member 50 at two points, and the gasket 60 can be abutted against the bolts 70 exposed from the cutouts 55 at two points. This makes it possible to position the sleeve-side flange 12F and the gasket 60 relative to the flange 90F.

[0046] Although the present specification and drawings disclose specific examples of the technology included in the scope of the claims, the technology described in the claims is not limited to these specific examples, but also includes various modifications and variations of the specific examples, and also includes parts of the specific examples taken out alone.

[0047] <Additional Notes> The following describes the features extracted from the above embodiment, while indicating, as necessary, the effects, etc. Note that, for ease of understanding, the corresponding configurations in the above embodiment are indicated in parentheses as appropriate below, but these features are not limited to the specific configurations indicated in parentheses.

[0048] The present disclosure relates to a positioning member and a pipe connection structure used at a pipe connection between a pair of flanges in a pipe and a fluid device, for positioning the fluid device relative to the pipe. For example, Japanese Patent Application Laid-Open No. 4-50726 (page 2, bottom left column, line 14 to bottom right column, line 14, Figures 1 and 2) discloses a positioning member that is attached to multiple fastening members that are inserted between a pair of flanges of a pipe. The conventional positioning members described above have a problem in that it is difficult to position a gasket to be installed between the flanges and the fluid device, and there is a need for the development of a technology that can solve this problem. In contrast, according to the present features, a positioning member that positions a fluid device relative to a pipe can position a gasket to be installed between the flanges and the fluid device.

[0049] [Feature 1] A positioning member (positioning member 50) is used in a piping connection section in which a fluid device (flow meter 10) is sandwiched between a pair of flanges (flanges 90F) in the middle of a pipe (piping 90) via a pair of gaskets (gaskets 60), and multiple fastening members (bolts 70) are passed through multiple through holes (through holes 71) in the pair of flanges and spanned between the pair of flanges.The positioning member is cylindrical and passed outside the fastening members, has one end fitted into a pair of through holes in each of the flanges and protrudes from each of the flanges, and positions the fluid device relative to the piping by contacting each end of the fluid device at two points.The positioning member has a notch (notch 55) that exposes the fastening members on the gasket side, so that each gasket can be positioned relative to the piping by contacting the fastening members at two points.

[0050] [Feature 2] This is a positioning member described in Feature 1, in which the other end opposite the one end that is fitted into the through hole has a stepped diameter and has a step portion (step portion 53) halfway in the axial direction.

[0051] [Feature 3] 3. The positioning member according to feature 2, wherein the step portion is located midway along the notch portion in the axial direction.

[0052] [Feature 4] The positioning member according to Feature 3, wherein the distance from the step portion to the end face of the other end portion of the notch is smaller than the thickness of the gasket.

[0053] [Feature 5] In the positioning member according to feature 2 or 3, the distance from the step portion of the notch to the end face on the other end side is equal to or greater than the thickness of the gasket.

[0054] [Feature 6] The positioning member according to any one of Features 1 to 5, further comprising a press-fit protrusion (press-fit protrusion 54) on the outer surface of the one end portion that is crushed by contact with the inner surface of the through hole.

[0055] [Feature 7] A pipe connection structure having a pair of flanges arranged midway along a pipe and facing each other across a fluid device, a pair of gaskets sandwiched between the pair of flanges and the fluid device, and a positioning member described in any one of features 1 to 6.

[0056] [Feature 8] Feature 7 is a structure of a pipe connection portion according to Feature 7, wherein the gasket is sandwiched between the flange and an end face of the notch of the positioning member that is farther from the flange.

[0057] The positioning members of Features 1 and 7 are cylindrical and passed through the outside of the fastening members, with one end fitting into a pair of through-holes in each flange and the other end protruding from each flange abutting each end of the fluid equipment at two points, thereby positioning the fluid equipment relative to the piping. The positioning members also have notches, and the gaskets placed between the flanges and the fluid equipment abut against the fastening members exposed from the notches at two points, thereby positioning the gasket relative to the piping. In other words, the gasket can be positioned by the positioning member that positions the flange and the fluid equipment. Furthermore, because the gasket can be received in the notches, it is possible to check whether there is any misalignment before assembling the flange and the fluid equipment.

[0058] According to the positioning member of Feature 2, a step portion is provided at one end that fits into the through hole of the flange, and the other end has a stepped portion that expands in diameter in a stepped manner. This allows the positioning member to be axially positioned relative to the flange. In this case, the notch may be provided only on the other end side of the step portion, or, as in Feature 3, the step portion may be provided so as to be located midway in the axial direction of the notch. In the latter case, if the distance from the step portion to the end face of the other end of the notch is made smaller than the thickness of the gasket, when inserting one end of the positioning member into the through hole, the gasket can be received in the notch before the step portion abuts the flange. Then, by further inserting the positioning member into the through hole, the gasket can be sandwiched and fixed between the end face of the other end of the notch and the flange. This makes it less likely for the gasket to fall out of the notch, facilitating the assembly of the fluid device to the piping (positioning members of Features 4 and 8).

[0059] Furthermore, if the distance from the step portion of the notch to the end face on the other end side is equal to or greater than the thickness of the gasket (positioning member of Feature 5), the gasket can be received after one end of the positioning member has been completely inserted into the through-hole. If the distance from the step portion of the notch to the end face on the other end side is greater than the thickness of the gasket, the gasket can be more easily received in the notch, reducing the effort required to install the gasket. Furthermore, if the distance from the step portion of the notch to the end face on the other end side is approximately the same as the thickness of the gasket, the gasket is held between the end face on the other end side of the notch and the flange, making it less likely to fall out of the notch, and facilitating the assembly of the fluid device to the piping.

[0060] Furthermore, according to the positioning member of feature 6, the outer surface of one end side is provided with a press-fit protrusion that abuts against the inner surface of the through hole and is crushed, making it difficult for the positioning member to fall out of the through hole and improving workability. [Explanation of symbols]

[0061] 10 Flow meter 20 Piping connection 50,50V,50W Positioning member 53 Step 54 Press-fit protrusion 55 Notch 60 gaskets 70 volts 71 Through hole 90 Piping 90F flange

Claims

1. A positioning member used in a piping connection in which a fluid device is sandwiched between a pair of flanges in the middle of a piping with a pair of gaskets interposed therebetween, and a plurality of fastening members are passed through a plurality of through-holes in the pair of flanges and are inserted between the pair of flanges, a positioning member having a cylindrical shape that is passed through the outside of the fastening member, one end of which is fitted into a pair of the through holes of each of the flanges, protruding from each of the flanges, and positioning the fluid device with respect to the piping at two points on each end of the fluid device, a positioning member having a notch that exposes the fastening member on the gasket side, so that each gasket is positioned relative to the piping by abutting the fastening member at two points;

2. 2. The positioning member according to claim 1, wherein the other end opposite to the one end fitted into the through hole has a stepped diameter and has a step partway in the axial direction.

3. The positioning member according to claim 2 , wherein the step portion is located midway along the notch portion in the axial direction.

4. The positioning member according to claim 3 , wherein the distance from the step portion to the end face of the other end portion of the notch is smaller than the thickness of the gasket.

5. 3. The positioning member according to claim 2, wherein the distance from the step portion to the end face of the other end portion of the notch is equal to or greater than the thickness of the gasket.

6. The positioning member according to claim 1 , further comprising a press-fit protrusion on an outer surface of the one end portion that is crushed by contact with an inner surface of the through hole.

7. a pair of flanges provided midway along the piping and facing each other with the fluid device in between; a pair of gaskets sandwiched between the pair of flanges and the fluid device; A structure of a pipe connection portion having the positioning member according to any one of claims 1 to 6.

8. The pipe connection structure according to claim 7 , wherein the gasket is sandwiched between the flange and an end face of the notch of the positioning member that is farther from the flange.

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