diaphragm valve

Abstract

To provide a diaphragm valve which can improve cutoff performance.SOLUTION: In a diaphragm valve 10, a stress dispersion plate 15 is arranged at a face 21b at a side opposite to a side connected to the other member 71 of a first flange part 21. The stress dispersion plate 15 is arranged at a face 22b at a side opposite to a side connected to the other member 75 of a second flange part 22. The first flange part 21 is connected to the other member 71 with a first bolt 81 penetrating together with the stress dispersion plate 15, and a first nut 82 screwed with the first bolt 81. The second flange part 22 is connected to the other member 75 with a second bolt 85 penetrating together with the stress dispersion plate 15, and a second nut 86 screwed with the second bolt 85. The first flange part 21 and the second flange part 22 are formed of polyethylene system resins. A thickness of the stress dispersion plate 15 is equal to or thicker than 1.5 mm, and equal to or thinner than 4 mm.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a diaphragm valve having a stress dispersion plate.

Background Art

[0002] Conventionally, in the manufacture of precision devices such as semiconductor devices or liquid crystal display devices, ultrapure water that has been purified to extremely high purity is used in wet processes such as cleaning. If metal ions or the like are present in water above a predetermined concentration, metal will adsorb onto the wafer surface or the like, which will adversely affect the quality of the precision device. Therefore, restrictions on impurities in ultrapure water have been thoroughly implemented.

[0003] The mixing of impurities into ultrapure water also occurs in the pipes that make up the ultrapure water transport line. As the material of the pipes, metals such as stainless steel with excellent gas barrier properties have sometimes been used, but considering the influence of metal elution from the pipes, it is considered preferable to use resin.

[0004] Among the resins used as materials for ultrapure water pipe materials, polyvinylidene fluoride (PVDF) has been put into practical use as pipes inside ultrapure water production equipment and as pipes for transporting ultrapure water from ultrapure water production equipment to use points in the semiconductor field, and it has become a technical standard for ultrapure water pipe materials.

[0005] Patent Document 1 discloses that PVDF is used in a diaphragm valve for ultrapure water.

[0006] Recently, with the improvement of the integration degree of semiconductor chips, circuit patterns have become increasingly finer, and they are more susceptible to the influence of low-level impurities. Therefore, the required water quality for ultrapure water has been continuously becoming stricter.

[0007] Also, PVDF is used as a fluororesin material with excellent chemical resistance and anti-contamination properties in chemical-resistant pipe materials.

[0008] Patent Document 2 discloses that PVDF is used in diaphragm valves for chemical-resistant applications. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent Publication No. 1-231984 [Patent Document 2] Patent Publication No. 2019-184063 Summary of the Invention [Problem to be solved by the invention]

[0010] Fluororesin piping such as PVDF has some disadvantages in terms of workability and cost compared to other common piping, but with the demands for ultrapure water quality becoming stricter, fluororesin piping is effectively the only option that meets the required water quality. The present inventors have deliberately focused on alternative materials for ultrapure water valves. For example, polyethylene-based resins, which are easy to install and cost-effective, are commonly used as piping materials. However, polyethylene-based resins have low long-term compressive strength, and when a bolted joint is tightened with a bolt and nut, creep deformation of the polyethylene occurs over time, reducing the bolt axial tension and leading to watertightness problems. For this reason, polyethylene is not currently used in valves that require long-term strength.

[0011] An object of the present disclosure is to provide a diaphragm valve that can improve watertightness. [Means for solving the problem]

[0012] To achieve the above object, a diaphragm valve according to a first aspect includes a first flange portion, a second flange portion, a diaphragm, a drive mechanism, a first stress distribution plate, and a second stress distribution plate. The first flange portion has an inlet of a flow path formed therein and is intended for connection to another member. The second flange portion has an outlet of the flow path formed therein and is intended for connection to another member. The diaphragm opens and closes the flow path. The drive mechanism closes or opens the flow path by driving the diaphragm. The first stress distribution plate is disposed on a first surface of the first flange portion opposite the side connected to the other member. The second stress distribution plate is disposed on a second surface of the second flange portion opposite the side connected to the other member. The first flange portion is connected to the other member by a first bolt that passes through the first flange portion together with the first stress distribution plate and a first nut that threads onto the first bolt. The first flange portion is connected to the other member by a second bolt that passes through the first flange portion together with the second stress distribution plate and a second nut that threads onto the second bolt. The first flange portion and the second flange portion are made of a polyethylene resin. The first stress dispersion plate and the second stress dispersion plate each have a thickness of 1.5 mm or more and 4 mm or less.

[0013] In this way, by placing a stress dispersion plate at the part where another member is fastened with a bolt and nut, compressive creep deformation due to fastening can be suppressed, and watertightness can be improved.

[0014] Furthermore, even when a polyethylene resin is used for the first flange portion and the second flange portion, the water-stopping property can be improved.

[0015] Furthermore, by specifying the thickness of the stress dispersion plate, it is possible to further improve the water-stopping property.

[0016] A diaphragm valve according to a second aspect is the diaphragm valve according to the first aspect, wherein the first stress distribution plate is formed to span two or more bolt fastening holes in the first flange portion, and the second stress distribution plate is formed to span two or more bolt fastening holes in the second flange portion.

[0017] By forming the stress dispersion plate so as to span two or more bolt fastening holes in this way, it becomes possible to further improve the water tightness.

[0018] The diaphragm valve according to the third aspect is the diaphragm valve according to the first or second aspect, and the area where the first stress dispersion plate contacts the first surface is 50% or more of the area of the first surface. The area where the second stress dispersion plate contacts the second surface is 50% or more of the area of the second surface.

[0019] By setting the installation area of the stress dispersion plate to 50% or more of the installation surface in this way, it becomes possible to further improve the water tightness.

[0020] The diaphragm valve according to the fourth aspect is the diaphragm valve according to any one of the first to third aspects, and the material of each of the first stress dispersion plate and the second stress dispersion plate is stainless steel.

[0021] By forming it with stainless steel in this way, it becomes possible to further improve the water tightness.

[0022] The diaphragm valve according to the fifth aspect is the diaphragm valve according to any one of the first to fourth aspects, and the Young's modulus of the material of each of the first bolt and the second bolt is 200 GPa or less.

[0023] In this way, by setting the Young's modulus of the material of the first bolt and the second bolt to 200 GPa or less, the water tightness can be improved.

[0024] The diaphragm valve according to the sixth aspect is the diaphragm valve according to any one of the first to fifth aspects, and the material of each of the first bolt and the second bolt is stainless steel.

[0025] By forming it with stainless steel in this way, it becomes possible to further improve the water tightness.

[0026] The diaphragm valve according to the seventh aspect is a diaphragm valve according to any one of the first to sixth aspects, and the materials of each of the first bolt and the second bolt are SUS304.

[0027] By using SUS304 with a relatively small Young's modulus in this way, when the bolt is tightened with the same tightening torque compared to the case where a bolt made of a material with a Young's modulus larger than that of SUS304 is used, the elongation of the bolt caused by tightening is larger for the bolt made of SUS304. Due to this influence, the depression due to the compression of the polyethylene-based resin existing near the bolt fastening hole in the flange portion of the diaphragm becomes smaller. As a result, it is considered that the axial force of the bolt is maintained better over a long period of time, and the torque holding rate becomes higher even after a certain period of time has passed.

[0028] The diaphragm valve according to the eighth aspect is a diaphragm valve according to any one of the first to seventh aspects, and the use of the diaphragm valve is for ultrapure water use or chemical-resistant use.

[0029] The diaphragm valve according to this aspect can improve the long-term water tightness, and thus can be used for ultrapure water use or chemical-resistant use.

Advantages of the Invention

[0030] According to the present disclosure, it is possible to provide a diaphragm valve capable of improving water tightness.

Brief Description of the Drawings

[0031] [Figure 1] External perspective view of the diaphragm valve of the embodiment according to the present disclosure [Figure 2] Partial cross-sectional configuration diagram of the diaphragm valve of the embodiment according to the present disclosure [Figure 3] Perspective view showing the valve body 11 of the diaphragm valve of the embodiment according to the present disclosure. [Figure 4] Cross-sectional view of the diaphragm valve of the embodiment according to the present disclosure. [Figure 5] FIG. 1 is a front view showing a state in which a diaphragm valve according to an embodiment of the present disclosure is connected to another member. [Figure 6] 1A is a front view showing a stress distribution plate according to an embodiment of the present disclosure; FIG. 1B is a front view showing a stress distribution plate according to an embodiment of the present disclosure; [Figure 7] (a) Front view showing the surface on which two stress distribution plates are arranged, (b) Front view showing the surface on which two stress distribution plates are arranged. [Figure 8A] FIG. 1 is a front view showing a state in which a diaphragm valve according to an embodiment of the present disclosure is connected to another member. [Figure 8B] 8B is an exploded view of the connection between the other member and the first flange portion in FIG. 8A. FIG. [Figure 9] FIG. 1A is a schematic cross-sectional view showing a state in which a flow channel is closed, and FIG. 1B is a schematic cross-sectional view showing a state in which the flow channel is open. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, a diaphragm valve according to an embodiment of the present disclosure will be described.

[0033] <1. Structure> Fig. 1 is a perspective view of the appearance of a diaphragm valve 10 according to an embodiment of the present disclosure. Fig. 2 is a partial cross-sectional view of the diaphragm valve 10 according to the present embodiment.

[0034] As shown in Figures 1 and 2, the diaphragm valve 10 of this embodiment includes a valve body 11, a diaphragm 12 (also called a diaphragm), a bonnet 13, a drive mechanism 14, and a stress dispersion plate 15 (see Figure 4).

[0035] The first flange portion 21 and the second flange portion 22 of the valve body 11 are connected to the flange of another member and the pipe, and a flow path 24 through which fluid flows is formed in the valve body 11. The diaphragm 12 opens or blocks the flow path 24. The bonnet 13 is attached to the valve body 11 so as to cover the diaphragm 12. A part of the drive mechanism 14 is disposed in the bonnet 13 and drives the diaphragm 12. The stress dispersion plate 15 is installed on the side opposite to the side connected to another member of the first flange portion 21 or the second flange portion 22 (see FIG. 4 described later).

[0036] (Valve body) FIG. 3 is a perspective view showing the valve body 11. FIG. 4 is a cross-sectional view of the diaphragm valve 10. FIG. 4 is a cross-sectional view taken along the arrow between AA' in FIG. 1. FIG. 5 is a front view showing the piping structure in a state where the diaphragm valve is connected to another member. In FIG. 4, in order to show the position of the stress dispersion plate 15, the state in which the stress dispersion plate 15 is arranged is shown although it is not fixed with bolts or the like.

[0037] For the valve body 11, PE (polyethylene) is used from the viewpoints of workability and low elution property. PE can be changed to desired properties by changing the catalyst species used during polymerization. Examples of the catalyst used include polymerization catalysts such as Ziegler-Natta catalysts, metallocene catalysts, and chromium oxide catalysts.

[0038] The polyethylene-based resin may be copolymerized with an α-olefin as necessary. Examples of the α-olefin copolymerized with the polyethylene-based resin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-butene-1-hexene, 1-butene-4-methyl-1-pentene, 1-butene-1-octene, and the like.

[0039] A material mainly composed of the above-mentioned PE was used for the valve body 11. The main component refers to the component having the highest content on a mass basis. The main component is a component having a content of at least 50%.

[0040] As shown in FIGS. 3 and 4, the valve body has a first flange portion 21, a second flange portion 22, a central portion 23, and a flow path 24.

[0041] The first flange portion 21, the second flange portion 22, and the central portion 23 are integrally formed, and the flow path 24 is formed across the first flange portion 21, the central portion 23, and the second flange portion 22, as shown in Figure 4.

[0042] A flange 72 and a pipe 73 of another member 71 are connected to the first flange portion 21. As shown in Fig. 4, the first flange portion 21 has a first flange surface 21a on which an inlet 24a through which fluid flows into the valve body 11 is formed, a surface 21b (an example of a first surface) on the valve body 11 side opposite the first flange surface 21a, and bolt fastening holes 21c (see Fig. 5) that penetrate from the first flange surface 21a to the surface 21b. As shown in Fig. 1, a plurality of bolt fastening holes 21c are formed around the inlet 24a, and in this embodiment, for example, four bolt fastening holes 21c are formed.

[0043] 5, the other member 71 has a pipe 73 and a flange 72 arranged at the end of the pipe 73. The flange 72 has a flange surface 72a that contacts the first flange surface 21a of the valve body 11, a surface 72b opposite the flange surface 72a, and bolt fastening holes 72c that penetrate from the flange surface 72a to the surface 72b. A plurality of bolt fastening holes 72c are formed around the inlet to the pipe 73 formed in the flange surface 72a; in this embodiment, for example, four bolt fastening holes 72c are formed.

[0044] In a state in which the other member 71 is disposed relative to the first flange portion 21 so that the flange surface 72a faces the first flange surface 21a and the bolt fastening holes 21c and 72c face each other, the flange 72 of the other member 71 is connected to the first flange portion 21. It is preferable to dispose a packing or the like between the first flange portion 21 and the flange 72.

[0045] The first flange portion 21 and the flange 72 of the other member 71 are connected using a first bolt 81 and a first nut 82. The first bolt 81 is inserted into the bolt fastening hole 21c of the first flange portion 21 and the bolt fastening hole 72c of the flange 72. The first nut 82 is screwed onto the tip of the first bolt 81 that passes through the bolt fastening hole 21c and the bolt fastening hole 72c. As a result, the first flange portion 21 and the flange 72 are fastened together by the first bolt 81 and the first nut 82.

[0046] The head of a first bolt 81 is disposed on the surface 72b of the flange 72, and a first nut 82 is disposed on the surface 21b side of the first flange portion 21. A stress distribution plate 15, which will be described later, is disposed between the first nut 82 and the valve body 11 (more specifically, on the surface 21b). The stress distribution plate 15 disposed on the surface 21b of the first flange portion 21 corresponds to an example of a first stress distribution plate.

[0047] A flange 76 of another member 75 and a pipe 77 are connected to the second flange portion 22. As shown in Fig. 4, the second flange portion 22 has a second flange surface 22a in which an outlet 24b through which fluid is discharged from the valve body 11 is formed, a surface 22b (an example of a second surface) on the valve body 11 side opposite the second flange surface 22a, and bolt fastening holes 22c (see Fig. 5) that penetrate from the second flange surface 22a to the surface 22b. A plurality of bolt fastening holes 22c are formed around the outlet 24b; for example, four bolt fastening holes are formed in this embodiment.

[0048] 5, the other member 75 has a pipe 77 and a flange 76 arranged at the end of the pipe 77. The flange 76 has a flange surface 76a that contacts the second flange surface 22a of the valve body 11, a surface 76b opposite the flange surface 76a, and bolt fastening holes 76c that penetrate from the flange surface 76a to the surface 76b. A plurality of bolt fastening holes 76c are formed around the inlet to the pipe 77 formed in the flange surface 76a; in this embodiment, for example, four bolt fastening holes 76c are formed.

[0049] In a state in which the other member 75 is disposed relative to the second flange portion 22 so that the flange surface 76a faces the second flange surface 22a and the bolt fastening holes 22c and 76c face each other, the flange 76 of the other member 75 is connected to the second flange portion 22. It is preferable to dispose a packing or the like between the second flange portion 22 and the flange 76.

[0050] The second flange portion 22 and the flange 76 of the other member 75 are connected using a second bolt 85 and a second nut 86. The second bolt 85 is inserted into the bolt fastening hole 22c of the second flange portion 22 and the bolt fastening hole 76c of the flange 76. The second nut 86 is screwed onto the tip of the second bolt 85 that passes through the bolt fastening hole 22c and the bolt fastening hole 76c. As a result, the second flange portion 22 and the flange 76 are fastened together by the second bolt 85 and the second nut 86.

[0051] The head of a second bolt 85 is disposed on the surface 76b of the flange 76, and a second nut 86 is disposed on the surface 22b side of the second flange portion 22. A stress distribution plate 15, which will be described later, is disposed between the second nut 86 and the valve body 11 (more specifically, on the surface 22b). The stress distribution plate 15 disposed on the surface 22b of the second flange portion 22 corresponds to an example of a second stress distribution plate.

[0052] The first bolt 81 and the second bolt 85 can be made of metals such as iron, copper, copper alloy, brass, aluminum, stainless steel, etc., but it is preferable to make them of stainless steel in order to maintain watertightness for a long period of time.

[0053] Examples of stainless steel include SUS303, SUS304, SUS316, SUS310S, SUS410, and SUS430. The Young's modulus of SUS303, SUS304, and SUS316 is 193 GPa, while the Young's modulus of SUS310S, SUS410, and SUS430 is 200 GPa. Therefore, it is preferable that the Young's modulus of the material of first bolt 81 and second bolt 85 is 200 GPa or less.

[0054] The first nut 82 and the second nut 86 can be made of a metal such as iron, copper, a copper alloy, brass, aluminum, or stainless steel.

[0055] The first flange portion 21 and the second flange portion 22 are disposed opposite each other as shown in Figures 3 and 4, and the first flange surface 21a and the second flange surface 22a are formed to face each other and be parallel to each other as shown in Figure 4. The position of the inlet 24a and the position of the outlet 24b also face each other.

[0056] As shown in FIG. 4, the central portion 23 is provided between the first flange portion 21 and the second flange portion 22. The central portion 23 has a connecting portion 23a connected to the first flange portion 21 and a connecting portion 23b connected to the second flange portion 22. The above-mentioned surface 21b is the surface on the central portion 23 side of the first flange portion 21 and surrounding the connecting portion 23a. The surface 21b is the portion parallel to the first flange surface 21a. The above-mentioned surface 22b is the surface on the central portion 23 side of the second flange portion 22 and surrounding the connecting portion 23b. The surface 22b is parallel to the second flange surface 22a.

[0057] The central portion 23 has a first surface 31 with an opening 31a formed in the center. As shown in FIGS. 3 and 4, the first surface 31 is generally planar and is formed perpendicular to the first flange surface 21a and the second flange surface 22a. As shown in FIG. 3, the opening 31a has a curved periphery. A protrusion 34 is formed along the periphery of the opening 31a. The diaphragm 12 is disposed inside this protrusion 34. Furthermore, a plurality of bolt holes 32 are formed in the first surface 31 around the opening 31a.

[0058] The direction along the line connecting the inlet 24a and the outlet 24b is defined as the first direction X, the direction perpendicular to the first direction X and parallel to the first surface 31 is defined as the second direction Y, and the direction perpendicular to the first surface 31 is defined as the third direction Z. The first direction X can also be said to be a direction along a straight line perpendicular to the first flange surface 21a and the second flange surface 22a.

[0059] As shown in FIG. 4, the flow path 24 is formed from an inlet 24a to an outlet 24b. The wall portion 33 is formed to project toward the first surface 31 at the center of the flow path 24. The wall portion 33 is formed such that the inner surface of the flow path 24 gently rises toward the first surface 31 so as to form an inclination in the flow path 24. The above-described opening 31a is formed at a position corresponding to the wall portion 33. A diaphragm 12, which will be described later, is pressed against the tip surface 33a on the first surface 31 side of the wall portion 33.

[0060] The flow path 24 includes an inlet-side flow path 241 formed from the inlet 24a of the first flange portion 21 to the wall portion 33, an outlet-side flow path 242 formed from the outlet 24b of the second flange portion 22 to the wall portion 33, and a communication portion 243 that communicates the inlet-side flow path 241 and the outlet-side flow path 242.

[0061] As shown in FIG. 4, the width of the inlet-side flow path 241 in the direction perpendicular to the first surface 31 (width in the third direction Z) becomes narrower as it approaches the wall portion 33. On the other hand, the width of the inlet-side flow path 241 in the direction parallel to the first surface 31 (width in the second direction Y) becomes wider as it approaches the wall portion 33 (see FIG. 2).

[0062] The outlet-side flow path 242 is formed from the outlet 24b of the second flange portion 22 to the wall portion 33. As shown in FIG. 4, the width of the outlet-side flow path 242 in the direction perpendicular to the first surface 31 (width in the third direction Z) becomes narrower as it approaches the wall portion 33. On the other hand, the width of the outlet-side flow path 242 in the direction parallel to the first surface 31 (width in the second direction Y) becomes wider as it approaches the wall portion 33.

[0063] The communication portion 243 is a portion of the flow path 24 on the first surface 31 side of the wall portion 33 and communicates the inlet-side flow path 241 and the outlet-side flow path 242.

[0064] (Diaphragm 12) As shown in FIGS. 2 and 4, the diaphragm 12 is disposed on the first surface 31 so as to close the opening 31a, and includes a diaphragm main body 41 and an engagement member 42.

[0065] The material of the diaphragm body 41 may be any rubber-like elastic body, and examples of suitable materials include ethylene propylene rubber, isoprene rubber, chloroprene rubber, chlorosulfonated rubber, nitrile rubber, styrene butadiene rubber, chlorinated polyethylene, fluororubber, EPDM (ethylene-propylene-diene rubber), PTFE (polytetrafluoroethylene), etc. PTFE with high cleanliness is used.

[0066] Also, a high-strength reinforcing cloth may be inserted into the diaphragm body 41, and it is desirable that the reinforcing cloth be made of nylon. This is preferable because it is possible to prevent deformation or damage of the diaphragm body 41 when fluid pressure is applied to the diaphragm body 41 when the diaphragm valve 10 is closed.

[0067] As shown in FIGS. 2 and 4, the outer peripheral edge portion 43 of the diaphragm body 41 is sandwiched between the bonnet 13 and the valve body 11, which will be described later.

[0068] The diaphragm 12 moves downward by the drive mechanism 14 described later and abuts against the tip surface 33a of the wall portion 33, thereby closing the communication portion 243 and closing the flow path 24. Also, when the diaphragm 12 moves upward by the drive mechanism 14 and separates from the tip surface 33a, the flow path 24 is opened.

[0069] (Bonnet 13) The bonnet 13, similar to the valve body 11, can be formed of resins such as PE (polyethylene), PVC (polyvinyl chloride), HT (heat-resistant vinyl chloride pipe), PP (polypropylene), or PVCF (polyvinylidene fluoride), polystyrene, ABS resin, polytetrafluoroethylene, perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, etc., or metals such as iron, copper, copper alloy, brass, aluminum, stainless steel, etc., or porcelain, etc. From the viewpoints of workability and cost, it is preferable to use PE (polyethylene).

[0070] 1 and 2, the bonnet 13 is fixed to the first surface 31 of the valve body 11 by a third bolt 88 and a third nut (not shown). The bonnet 13 is provided so as to cover the opening 31a via the diaphragm 12.

[0071] As shown in Figures 2 and 4, the bonnet 13 has an opening 13a corresponding to the first surface 31, and has a through hole 13b opposite the opening 13a in which a sleeve 62 and a stem 63, described later, are disposed.

[0072] (Drive mechanism 14) The drive mechanism 14 includes a compressor 61 , a sleeve 62 , a stem 63 , and a handle 64 .

[0073] Compressor 61 is made of PVDF (polyvinylidene fluoride) or the like, and is connected to diaphragm 12. An engaging member 42 is embedded in diaphragm body 41, and engaging member 42 protrudes from the opposite side (non-liquid-contacting side) of valve body 11. The protruding portion of engaging member 42 engages with compressor 61, connecting compressor 61 and diaphragm 12.

[0074] The sleeve 62 is supported in a through hole 13b of the bonnet 13. The sleeve 62 has a threaded shape formed on the inside thereof.

[0075] The stem 63 is disposed inside the sleeve 62, and the threaded portion formed on the outer periphery is threadedly engaged with the threaded portion formed inside the sleeve 62. The compressor 61 is fixed to the end of the stem 63 that is disposed inside the bonnet 13.

[0076] The compressor 61 is engaged with the diaphragm 12 on the valve body 11 side, and is fixed to the stem 63 on the opposite side to the valve body 11 .

[0077] The handle 64 is engaged with the outer periphery of the portion of the stem 63 that is positioned outside the bonnet 13 .

[0078] (Stress distribution plate 15) The stress dispersion plate 15 can be made of strong metals such as iron, copper, copper alloy, brass, aluminum, stainless steel, or porcelain, with stainless steel being preferred from the viewpoint of achieving both strength and ease of installation. Examples of stainless steel that can be used include SUS304, SUS316, SUS303, SUS317, and SUS403.

[0079] As shown in FIG. 5, the stress dispersion plate 15 is fixed between the valve body 11 and a first nut 82 and between the valve body 11 and a second nut 86 using a first bolt 81 and a second bolt 85 .

[0080] 6(a) and 6(b) are plan views showing the stress dispersion plate 15. FIG.

[0081] As shown in Figures 6(a) and 6(b), each stress distribution plate 15 is shaped to span two or more bolt fastening holes 21c or bolt fastening holes 22c of the first flange portion 21 or the second flange portion 22.

[0082] 6(a) has a substantially semicircular shape. A circular notch 15b is formed in the center of the radius shape of the stress dispersion plate 15.

[0083] Fig. 7(a) is a front view showing the surface 21b on which two stress distribution plates 15 are arranged. Fig. 7(a) is a view seen along the arrow B shown in Fig. 1, which is parallel to the first direction X. Note that in Fig. 7(a), the stress distribution plates 15 are indicated by dots for the sake of explanation.

[0084] As shown in Fig. 7(a), two stress dispersion plates 15 are arranged on the surface 21b adjacent to each other to form a circle. The connecting portion 23a (see Fig. 4) of the central portion 23 to the first flange portion 21 passes through the cutouts 15b of the two adjacent stress dispersion plates 15.

[0085] Two bolt holes 15a are formed in one stress distribution plate 15, and the bolt holes 15a face bolt fastening holes 21c on the surface 21b. As shown in Fig. 5, a first bolt 81 is inserted through the bolt fastening holes 72c of the flange 72, the bolt fastening holes 21c of the first flange portion 21, and the bolt hole 15a in the stress distribution plate 15, and a first nut 82 is screwed onto the tip of the first bolt 81 protruding from the bolt hole 15a. The stress distribution plate 15 is sandwiched between the first nut 82 and the surface 21b.

[0086] Fig. 7(b) is a front view showing the surface 22b on which two stress distribution plates 15 are arranged. Fig. 7(b) is a view seen along the arrow C shown in Fig. 1, and the arrow C is a direction parallel to the first direction X. In Fig. 7(b), the stress distribution plates 15 are indicated by dots for the sake of explanation.

[0087] As shown in Fig. 7(b), two stress dispersion plates 15 are arranged adjacent to each other to form a circle on the surface 22b. The connecting portion 23b (see Fig. 4) of the center portion 23 to the second flange portion 22 passes through the cutouts 15b of the two adjacent stress dispersion plates 15.

[0088] Two bolt holes 15a are formed in one stress distribution plate 15, facing bolt fastening holes 22c on surface 22b. A second bolt 85 is inserted through bolt fastening hole 76c in flange 76, bolt fastening hole 22c in second flange portion 22, and bolt hole 15a in stress distribution plate 15, and a second nut 86 is screwed onto the tip of second bolt 85 protruding from bolt hole 15a. The stress distribution plate 15 is sandwiched between second nut 86 and surface 22b.

[0089] In this way, in this embodiment, a stress dispersion part is provided to distribute the stress caused by fastening bolts and nuts when connecting the flange of another part to the flange part of the diaphragm valve. This stress dispersion part is made up of, for example, two semicircular members (stress dispersion plates 15) as shown in Fig. 6(a), but it may also be a single member in which two semicircular stress dispersion plates 15 are connected at connecting part 15c with screws or the like as shown in Fig. 6(b).

[0090] The area of the stress dispersion plate 15 is 50% or more, more preferably 70% or more, and even more preferably 80% or more of the area of the surface 21b on the central portion 23 side of the first flange portion 21 or the area of the surface 22b on the central portion 23 side of the second flange portion 22 in order to disperse the stress caused by the bolt fastening.

[0091] The thickness of the stress dispersion plate 15 is set to be 1.5 mm or more and 4 mm or less so that it can withstand the axial force of the bolt fastening and there is no problem with workability.

[0092] Although the connection with other members has been described with reference to FIG. 5, it is not limited thereto. For example, as shown in FIG. 8A, it may be connected to other members 71′ and 75′. The other member 71′ shown in FIG. 8A is formed such that the diameter of the flange 72′ is smaller than the diameter of the first flange portion 21 (it can be said to be a small face seat) as compared with the other member 71 of the piping structure shown in FIG. 5. Further, the other member 75′ shown in FIG. 8A is formed such that the diameter of the flange 76′ is smaller than the diameter of the second flange portion 22 as compared with the other member 75 of FIG. 5. In the configuration shown in FIG. 8A, the connection portions 23a′ and 23b′ at the central portion 23′ of the valve body 11 are also formed thinner than those in FIG. 5.

[0093] In the configuration shown in FIG. 8A, the other member 71′ is connected to the first flange portion 21 by a pressing member 91, a first bolt 81, and a first nut 82. Further, the other member 75′ is connected to the second flange portion 22 by a pressing member 92, a second bolt 85, and a second nut 86.

[0094] Taking the connection between the other member 71′ and the first flange portion 21 as an example for explanation. FIG. 8B is an exploded view of the connection between the other member 71′ and the first flange portion 21. As shown in FIG. 8B, the other member 71′ has a flange 72′ and a pipe 73′. The flange 72′ has a flange surface 72a′ facing the first flange surface 21a and a surface 72b′ on the side opposite to the flange surface 72a′. Unlike the flange 72, the flange 72′ is not provided with bolt fastening holes 72c.

[0095] The pressing member 91 presses the flange 72′ against the first flange surface 21a. The pressing member 91 is a plate-shaped member having a through hole 91d through which the piping 73′ is inserted. The pressing member 91 has a pressing surface 91a that presses against the surface 72b′ of the flange 72′, a surface 91b opposite the pressing surface 91a, and a bolt fastening hole 91c formed from the pressing surface 91a to the surface 91b. A first bolt 81 is inserted into the bolt fastening hole 91c of the pressing member 91, the bolt fastening hole 21c of the first flange portion 21, and the bolt hole 15a of the stress dispersion plate 15, and a first nut 82 is screwed onto the tip of the first bolt 81 protruding from the bolt hole 15a. By tightening the first nut 82, the pressing member 91 presses the flange 72′ against the first flange portion 21. The head of the first bolt 81 is positioned on the surface 91b of the pressing member 91, the first nut 82 is positioned on the surface 21b side of the first flange portion 21, and a stress distribution plate 15 is positioned between the first nut 82 and the first flange portion 21.

[0096] In this way, even another member 71 ′ provided with a flange 72 ′ of the small face seat can be connected to the first flange portion 21 .

[0097] The same applies to the connection between the other member 75 and the second flange portion 22.

[0098] The other member 75' has a flange 76' and a pipe 77'. The flange 76' has a flange surface 76a' facing the second flange surface 22a and a surface 76b' opposite the flange surface 76a'. Unlike the flange 76, the flange 76' does not have bolt fastening holes 76c.

[0099] The pressing member 92 presses the flange 76′ against the second flange surface 22a. The pressing member 92 is a plate-shaped member having a through hole 92d through which the piping 77′ is inserted. The pressing member 92 has a pressing surface 92a that presses against the surface 76b′ of the flange 76′, a surface 92b opposite the pressing surface 92a, and a bolt fastening hole 92c formed from the pressing surface 92a to the surface 92b. Second bolts 85 are inserted into the bolt fastening holes 92c of the pressing member 92, the bolt fastening holes 22c of the second flange portion 22, and the bolt holes 15a of the stress distribution plate 15, and a second nut 86 is screwed onto the tip of the second bolt 85 protruding from the bolt hole 15a. By tightening the second nut 86, the pressing member 92 presses the flange 76′ against the second flange portion 22. The head of the second bolt 85 is positioned on the surface 92b of the pressing member 92, the second nut 86 is positioned on the surface 22b side of the second flange portion 22, and a stress distribution plate 15 is positioned between the second nut 86 and the second flange portion 22.

[0100] In this way, even another member 75 ′ provided with a flange 76 ′ of the small face seat can be connected to the second flange portion 22 .

[0101] <2. Operation> Next, the operation of the diaphragm valve 10 of this embodiment will be described. Figures 9(a) and 9(b) are diagrams that schematically show the operation of the diaphragm 12.

[0102] 9(a) in which the flow path 24 is open, when the handle 64 is rotated in a direction to close the flow path 24, the stem 63 moves toward the flow path 24 in accordance with the rotation of the handle 64. As the stem 63 moves, the compressor 61 fixed to the end of the stem 63 also moves toward the flow path.

[0103] As the compressor 61 moves toward the flow path 24, the diaphragm 12 curves convexly toward the wall portion 33 and is pressed against the tip end surface 33a of the wall portion 33, as shown in FIG. 9(b).

[0104] As a result, the flow path 24 of the diaphragm valve 10 is blocked.

[0105] On the one hand, when the handle 64 is rotated in the opening direction, the stem 63 moves to the side opposite to the flow path 24 as the handle 64 rotates. Along with the movement of the stem 63, the compressor 61 also moves, and the central portion of the diaphragm 12 engaged with the compressor 61 moves as shown in Fig. 9(a).

[0106] As a result, the flow path 24 of the diaphragm valve 10 is in an open state.

[0107] <3. Applications> (Ultra-pure water applications) The diaphragm valve 10 according to the embodiment of the present disclosure can be used for the transport piping of ultrapure water. Specifically, the diaphragm valve 10 according to the embodiment of the present disclosure can be used for piping within an ultrapure water production device, piping for transporting ultrapure water from the ultrapure water production device to a use point, and piping for returning ultrapure water from the use point, etc.

[0108] The diaphragm valve 10 according to the embodiment of the present disclosure is preferably used for transport piping of ultrapure water in wet treatment processes such as cleaning in piping for nuclear power plant water, or in the manufacturing process of pharmaceuticals, semiconductor elements or liquid crystals, more preferably in the manufacturing process of semiconductor elements where the required water quality for ultrapure water is particularly strict. As for the semiconductor element, those having a higher integration degree are preferred, and specifically, it is more preferably used in the manufacturing process of semiconductor elements with a minimum line width of 65 nm or less. Examples of the standards regarding the quality of ultrapure water used in semiconductor manufacturing include SEMIF75.

[0109] (Chemical-resistant applications) The diaphragm valve 10 according to the embodiment of the present disclosure can be used for the transport piping of chemical liquids. It can be used for transport piping of highly corrosive fluids or fluids requiring contamination prevention in chemical factories, semiconductor manufacturing fields, liquid crystal manufacturing fields, food fields, etc.

[0110] In the semiconductor manufacturing process, the surface of a silicon wafer (substrate) is cleaned with diluted chemical solutions. This is done to remove particles, metal contaminants, oxide films, etc., and a processing solution made by mixing multiple chemical solutions and pure water in appropriate ratios is used. Processing solutions include APM (ammonia, hydrogen peroxide, and pure water), HPM (hydrochloric acid, hydrogen peroxide, and pure water), DHF (hydrofluoric acid and pure water), and SPM (sulfuric acid and hydrogen peroxide), etc.

[0111] The diaphragm valve 10 of the embodiment according to the present disclosure is preferably used as a transport pipe for APM (ammonia, hydrogen peroxide, and pure water), HPM (hydrochloric acid, hydrogen peroxide, and pure water), DHF (hydrofluoric acid and pure water), SPM (sulfuric acid and hydrogen peroxide), etc.

[0112] <4. Other embodiments> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0113] (A) In the above embodiment, the stress distribution plate 15 is disposed between the first nut 82 and the surface 21b. However, this is not limiting, and the positions of the first nut 82 and the head of the first bolt 81 may be reversed. That is, in the example of the piping structure of FIG. 5, the first nut 82 may be disposed on the surface 72b of the flange 72, and the stress distribution plate 15 may be disposed between the head of the first bolt 81 and the surface 21b. Similarly, the stress distribution plate 15 may not be disposed between the second nut 86 and the surface 22b, and the positions of the second nut 86 and the head of the second bolt 85 may be reversed. That is, the second nut 86 may be disposed on the surface 76b of the flange 76, and the stress distribution plate 15 may be disposed between the head of the second bolt 85 and the surface 22b. The same applies to the piping structure of FIG. 8A.

[0114] (B) In the above embodiment, two bolt holes 15a are formed in one stress distribution plate 15, but this is not limited to this. For example, three or more bolt holes may be formed. The number of bolt fastening holes 21c in the first flange portion 21 and the number of bolt fastening holes 22c in the second flange portion 22 are not limited to four.

[0115] (C) In the above embodiment, two stress distribution plates 15 or one stress distribution member consisting of two stress distribution plates 15 connected to each other are arranged on surfaces 21b and 22b, but if the number of bolt fastening holes 21c and bolt fastening holes 22c is five or more, three or more stress distribution plates 15 may be arranged on surfaces 21b and 22b.

[0116] (D) In the above embodiment, the stress dispersion plate 15 is formed in a circular shape so as to fit the outer shapes of the surfaces 21b and 22b, but the shape is not limited to a circular shape.

[0117] (E) In the diaphragm valve 10 of the above embodiment, the manual handle 64 is provided as an example of a drive unit, but the stem 63 may be driven by an air-driven or electrically driven drive unit. [Example]

[0118] Next, an embodiment of the present disclosure will be described using examples.

[0119] [Valve body configuration] The valve body 11 of the diaphragm valve 10 is injection molded using the following materials by a conventional molding method.

[0120] HB534N (Japan Polyethylene Co., Ltd.) [Stress distribution plate configuration] In Examples 1 and 2 and Comparative Examples 1 to 3, diaphragm valves were used in which the thickness t of the stress dispersion plate 15 made of SUS304 was changed to 5.0 mm, 3.0 mm, 2.0 mm, 1.0 mm, or 0 mm (no stress dispersion plate).

[0121] The area occupancy rate of the prepared stress dispersion plate was measured. The area occupancy rate is the value obtained by dividing the area of the stress dispersion plate 15 by the area of the surface 21b on the central portion 23 side of the first flange portion 21.

[0122] [Stress relaxation test] The stress relaxation test of the flange portion (for example, the first flange portion 21) of the diaphragm valve was carried out according to the following procedure. 1) Using a band saw, only the flange portion of the diaphragm valve was cut to prepare a flange cutting piece. 2) Using four M16 bolts (material: SCM435), in order from the head side of the bolt, a stress dispersion plate, a flange cutting piece, a packing (manufactured by Sekisui Chemical Co., Ltd., Esflon PTFE packing 50A JIS10K (PP50)), and a stainless steel pipe flange (manufactured by MIE Techno Co., Ltd., SUSF304-TRFF-10K-50A) were connected to prepare a sample. Hereinafter, this sample is referred to as the "sample for stress relaxation test". 3) After setting the sample for stress relaxation test on a uniaxial testing machine (manufactured by Orientec Co., Ltd., RTF-2430-W-XL-S), the lifting plate of the uniaxial testing machine was brought into contact with the bolts of the sample for stress relaxation test, and an initial load of 43.75 kN was applied to the bolts of the sample for stress relaxation test. 4) After applying the initial load, the height of the lifting plate of the uniaxial testing machine was fixed for 3 hours, and the load applied to the uniaxial testing machine was measured.

[0123] [Evaluation] Table 1 shows the load after 3 hours, the load retention ratio, and the determination results of workability for the diaphragm valves of Example 1, 2 and Comparative Examples 1 to 3.

[0124] The load retention ratio is the value obtained by dividing the load after 3 hours by the initial load. When the stress dispersion plate can be installed, the workability is marked as 〇, and when it cannot be installed, the workability is marked as ×.

[0125] A load retention rate of 85% or more and workability of ◯ was rated as good (◯), and a load retention rate of less than 85% or workability of × was rated as poor (×).

[0126] [Table 1] In Example 1, the load and workability were evaluated using a diaphragm valve with a stress dispersion plate thickness t of 2.0 mm. The diaphragm valve of Example 1 had a load retention rate of 89.5%, and the workability was rated as good.

[0127] In Example 2, the load and workability were evaluated using a diaphragm valve with a stress dispersion plate thickness t of 3.0 mm. The diaphragm valve of Example 2 had a load retention rate of 94.3%, and the workability was rated as good.

[0128] In Comparative Example 1, the load and workability were evaluated using a diaphragm valve without the stress dispersion plate. The diaphragm valve of Comparative Example 1 had a load retention rate of 52.6%, and the workability was rated as good, resulting in a poor evaluation.

[0129] In Comparative Example 2, the load and workability were evaluated using a diaphragm valve with a stress dispersion plate thickness t of 1.0 mm. The diaphragm valve of Comparative Example 2 had a load retention rate of 57.4%, and the workability was rated as good and poor.

[0130] In Comparative Example 3, the workability was evaluated using a diaphragm valve with a stress dispersion plate thickness t of 5.0 mm. The workability of the diaphragm valve of Comparative Example 3 was evaluated as x, and the evaluation was poor.

[0131] [Long-term tightening torque measurement] A long-term tightening torque evaluation of a flange portion (for example, first flange portion 21) of a diaphragm valve was carried out according to the following procedure. 1) A sample was prepared by connecting four M16 bolts, in order from the head side of the bolts, a stainless steel pipe flange (MIE Techno Co., Ltd., SUSF304-TRFF-10K-50A), a packing (Sekisui Chemical Co., Ltd., Eslon PTFE packing 50A JIS10K (PP50)), the flange part of the diaphragm valve, a stress distribution plate, and an M16 nut. 2) Using an M16 wrench and a digital torque wrench, four M16 bolts were tightened to 35 N·m each. 3) The sample was left standing in a constant temperature environment of 23°C for 1,500 hours. 4) Using an M16 wrench and a digital torque wrench, the tightening torque of the four bolts was measured after 1,500 hours using the retightening method.

[0132] Table 2 shows the tightening torque (average tightening torque of the four bolts) and tightening torque retention rate after 1,500 hours for the diaphragm valves of Examples 3 and 4 and Comparative Examples 4 to 7.

[0133] The tightening torque retention rate is the tightening torque after 1,500 hours divided by the initial tightening torque (35 N·m).

[0134] A tightening torque retention rate of 50% or more and workability of ○ was rated as good (○), and a tightening torque retention rate of less than 50% or workability of × was rated as poor (×). [Table 2]

[0135] As shown in Table 2, the diaphragm valve (Example 3-6) equipped with a stress dispersion plate having a thickness of 1.5 mm or more and 4 mm or less exhibited a good tightening torque retention rate, and was able to improve watertightness.

[0136] On the other hand, the diaphragm valves without stress dispersion plates (Comparative Examples 4 and 5) or the diaphragm valve with a stress dispersion plate having a thickness of 1.5 mm or less (Comparative Example 6) were unable to achieve a sufficient tightening torque retention rate.

[0137] Furthermore, in the diaphragm valve (Comparative Example 7) equipped with a stress dispersion plate having a thickness of 5 mm, the tightening torque retention rate was good, but the workability was rated as x, and the evaluation was poor.

[0138] Furthermore, as shown by the comparison between Example 3 and Example 4, and between Example 5 and Example 6, the use of SUS304 bolts results in a better tightening torque retention rate than the use of SCM435 bolts. The following factors are presumed to be the cause of this.

[0139] That is, SUS304 has a smaller Young's modulus than SCM435, and when the bolts are tightened with the same tightening torque, the bolt elongates more when tightened with a SUS304 bolt. This reduces the collapse of the polyethylene resin near the bolt fastening holes (e.g., bolt fastening hole 21c) in the flange of the diaphragm due to compression. As a result, the axial force of the bolt is maintained for a longer period of time, and the torque retention rate is thought to be higher even after a certain period of time has passed.

[0140] As described above, it has been discovered that by installing a stress dispersion plate at the bolt fastening section of a diaphragm valve made of polyethylene resin, compressive creep deformation due to bolt tightening can be suppressed and watertightness can be maintained without impairing the function of the valve as a valve for ultrapure water. [Industrial Applicability]

[0141] The diaphragm valve of the present disclosure has the effect of improving watertightness and can be used in ultrapure water applications, chemical-resistant applications, and the like. [Explanation of symbols]

[0142] 10: Diaphragm valve 15: Stress dispersion plate 21: First flange part 21b: Surface 22: Second flange part 22b: Surface 24: Flow path 24a: Inlet 24b: Outlet 71: Other member 75: Other member

Claims

1. An inlet of a flow path is formed, a first flange portion for the purpose of connection with a first other member, an outlet of the flow path is formed, a second flange portion for the purpose of connection with a second other member, a diaphragm for opening and closing the flow path, a drive mechanism for closing or opening the flow path by driving the diaphragm, a first stress dispersion plate disposed on a first surface of the first flange portion on a side opposite to a side connected to the first other member, a second stress dispersion plate disposed on a second surface of the second flange portion on a side opposite to a side connected to the second other member without being connected to the first stress dispersion plate, The first flange portion is connected to a flange at a tip of the first other member by a first bolt passing through together with the first stress dispersion plate and a first nut screwed onto the first bolt, and the flange of the first other member is sandwiched between a first pressing member through which the first bolt passes and the first flange portion. The flange of the first other member has a smaller diameter than the first pressing member and the first flange portion, and the first bolt is disposed outside the flange of the first other member. The second flange portion is connected to a flange at a tip of the second other member by a second bolt passing through together with the second stress dispersion plate and a second nut screwed onto the second bolt, and the flange of the second other member is sandwiched between a second pressing member through which the second bolt passes and the second flange portion. The flange of the second other member has a smaller diameter than the second pressing member and the second flange portion, and the second bolt is disposed outside the flange of the second other member. The first flange portion and the second flange portion are formed of a polyethylene-based resin. The thickness of each of the first stress dispersion plate and the second stress dispersion plate is 1.5 mm or more and 4 mm or less. The Young's modulus of the material of each of the first bolt and the second bolt is 200 GPa or less. A diaphragm valve.

2. The first stress dispersion plate is formed to extend across two or more bolt fastening holes of the first flange portion. The second stress dispersion plate is formed to extend across two or more bolt fastening holes of the second flange portion. The diaphragm valve according to Claim 1.

3. The area where the first stress dispersion plate contacts the first surface is 50% or more of the area of the first surface. The area where the second stress dispersion plate contacts the second surface is 50% or more of the area of the second surface. The diaphragm valve according to claim 1 or 2.

4. The material of each of the first stress dispersion plate and the second stress dispersion plate is stainless steel, The diaphragm valve according to any one of claims 1 to 3.

5. The material of each of the first bolt and the second bolt is stainless steel, the diaphragm valve according to any one of claims 1 to 4.

6. The material of each of the first bolt and the second bolt is SUS304, the diaphragm valve according to any one of claims 1 to 5.

7. The use of the diaphragm valve is for ultrapure water use or chemical-resistant use, The diaphragm valve according to any one of claims 1 to 6.

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