Joint structure and connection structure

Abstract

To provide a stub end capable of suppressing generation of a gap in which particles remain.SOLUTION: A joint structure is configured such that a flare part 23 of a stub end 11 is used to connect pipes, and is made of a resin material, the joint structure comprising a flow path 24, a contact surface 23a, and a chamfered part 23b. Liquid flows through the flow path 24. The contact surface 23a is arranged around an opening 24b of the flow path 24, and comes into contact with a packing 13 that is arranged between itself and an object to be connected. The chamfered part 23b is formed by C-chamfering on the edge of the opening 24b, and is arranged between an inner peripheral surface 24c of the flow path 24 and the contact surface 23a. In a cross section including a central axis O of the flow path 24, an angle between an extension line L1 of the inner peripheral surface 24c and a line L2 on the chamfered part 23b is larger than or equal to 10 degrees and less than 60 degrees.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to joint structures and connection structures. [Background technology]

[0002] BACKGROUND ART In factory piping and the like, the end of a pipe is connected to the end of another pipe by a pipe joint structure (see, for example, Patent Document 1).

[0003] The pipe joint structure shown in Patent Document 1 comprises a packing, stub ends arranged on both sides of the packing, and loose flanges provided on the outer periphery of each stub end, and the loose flanges are fastened with bolts. This fastening causes the stub ends to compress the ribs of the packing, causing the ribs to collapse and maintaining sealing performance.

[0004] Fig. 12 is a schematic diagram showing a state in which a packing 1003 is compressed by a pair of stub ends 1001, 1002 in a conventional pipe fitting structure. Fig. 12 shows a flow path 1004 through which a liquid flows. The packing 1003 has protrusions 1005 formed on both sides of the stub ends 1001, 1002. The protrusions 1005 are compressed by the contact surfaces 1006 of the stub ends 1001, 1002, ensuring the sealing of the flow path 1004. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-162147 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the configuration shown in Patent Document 1, the difference between the inner diameter of the sealing member and the inner diameter of the opening of the flow path at the stub end may cause a stagnation area S shown in Figure 12 to be generated, and a vortex may be generated in the stagnation area S, which may result in particles being generated after water passes through the piping.

[0007] An object of the present disclosure is to provide a joint structure and a connection structure that can suppress the occurrence of accumulation areas where particles accumulate. [Means for solving the problem]

[0008] In order to achieve the above object, a joint structure according to a first aspect is used for connecting pipes and is formed from a resin material, and includes a flow path, a contact surface, and a chamfered portion. A liquid flows through the flow path. The contact surface is disposed around the opening of the flow path and contacts a seal member disposed between the opening and the connection object. The chamfered portion is formed by C-chamfering on the edge of the opening and is disposed between the inner circumferential surface of the flow path and the contact surface. In a cross section including the central axis of the flow path, the angle formed between an extension line of the inner circumferential surface and a line on the chamfered portion is 10 degrees or more and less than 60 degrees.

[0009] In this way, by forming a chamfered portion using C-chamfering processing and making the angle between the extension line of the inner surface and the line on the chamfered portion in a cross section including the central axis of the flow path 10 degrees or more and less than 60 degrees, it is possible to reduce the difference between the inner diameter of the sealing member and the inner diameter of the opening of the joint structure, thereby suppressing the occurrence of retention areas where particles can accumulate.

[0010] A joint structure according to a second aspect is used for connecting pipes and is made of a resin material, and includes a flow path, a contact surface, and a chamfered portion. Liquid flows through the flow path. The contact surface is disposed around the opening of the flow path and contacts a seal member disposed between the opening and the object to be connected. The chamfered portion is formed by C-chamfering on the edge of the opening and is disposed between the inner circumferential surface of the flow path and the contact surface. If the inner diameter of the connection portion between the contact surface and the chamfered portion is d1 and the inner diameter of the seal member is d2, then the relationship 0≦(((d2-d1) / 2) / d2)×100≦1.9 is satisfied.

[0011] In this way, a chamfered portion is formed by C-chamfering, the inner diameter of the connection portion between the contact surface and the chamfered portion is d1, and the inner diameter of the sealing member is d2. By satisfying 0≦(((d2-d1) / 2) / d2)×100≦1.9, it is possible to reduce the difference between the inner diameter of the sealing member and the inner diameter of the opening of the joint structure, and to suppress the occurrence of retention areas where particles can accumulate.

[0012] A joint structure according to a third aspect is the joint structure according to the first or second aspect, in which the resin material is polyethylene.

[0013] In this way, by using polyethylene as the material for the joint structure, the joint structure and the pipe can be joined by heat fusion, etc. Furthermore, since it can be easily cut on site, it is easy to adjust the length, etc.

[0014] A joint structure according to a fourth aspect is the joint structure according to the third aspect, in which the polyethylene is high-density polyethylene.

[0015] In this way, by using high density polyethylene as the material for the joint structure, rigidity and strength can be ensured, and therefore the collapse of the convex portion of the sealing member can be further increased.

[0016] The joint structure according to the fifth aspect is used for cleaning semiconductors.

[0017] This allows ultrapure water used for cleaning semiconductors to flow.

[0018] A connection structure according to a sixth aspect includes a first stub end, a second stub end, a seal member, a first flange, a second flange, and a fastening portion. The first stub end has the joint structure according to the first or second aspect. The second stub end has the joint structure according to the first or second aspect. The seal member is disposed between the contact surface of the first stub end and the contact surface of the second stub end. The first flange is disposed around the first stub end. The second flange is disposed around the second stub end. The fastening portion fastens the first flange and the second flange together.

[0019] This makes it possible to reduce the difference in the inner diameter of the seal member and the inner diameter of the opening of the stub end joint structure in the connection structure, thereby suppressing the occurrence of accumulation areas where particles may accumulate. [Effects of the Invention]

[0020] According to the present disclosure, it is possible to provide a joint structure and a connection structure that can suppress the occurrence of accumulation portions where particles accumulate. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view showing a state in which a first pipe and a second pipe are connected to the connection structure of the present embodiment. FIG. [Figure 2] 1 is a perspective view showing a state before a first pipe and a second pipe are connected to the connection structure of the present embodiment. FIG. [Figure 3] FIG. 2 is a cross-sectional view of the connection structure of the present embodiment. [Figure 4] 1A is a front cross-sectional view of a stub end of the present embodiment, and FIG. 1B is a bottom view of the stub end of the present embodiment. [Figure 5] FIG. 10 is a schematic cross-sectional view of a stub end for explaining the inclination of the contact surface. [Figure 6] 6(a) is a plan view of the packing of the present embodiment, (b) is a cross-sectional view taken along the line AA in FIG. 6(a), and (c) is an enlarged view of part B in FIG. 6(b). [Figure 7] FIG. 4 is an enlarged view of a portion T in FIG. 3. [Figure 8] 8(a) is a front view of the flange of this embodiment, (b) is a cross-sectional view taken along the line CC in FIG. 8(a), and (c) is a cross-sectional view taken along the line DD in FIG. 8(a). [Figure 9] 10 is a schematic cross-sectional view showing a state in which a packing is compressed by a pair of stub ends in the connection structure of the present embodiment. FIG. [Figure 10] FIG. 10 is a schematic cross-sectional view of a stub end in a comparative example. [Figure 11] FIG. 1A is a diagram illustrating the configurations of an example and a comparative example for which simulations were performed, and FIG. 1B is a diagram illustrating the configuration of a stub end of a comparative example in which θ=0 degrees. [Figure 12] FIG. 10 is a cross-sectional schematic view showing a state in which a packing is compressed by a pair of stub ends in a conventional pipe joint structure. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, a joint structure and a connection structure using the joint structure according to an embodiment of the present disclosure will be described with reference to the drawings.

[0023] <Configuration> (Overview of connection structure 3) Fig. 1 is a perspective view showing a connection structure 3 in which a first pipe 1 and a second pipe 2 are connected. Fig. 2 is a perspective view showing a state before the first pipe 1 and the second pipe 2 are attached to the connection structure 3.

[0024] End 1a of first pipe 1 shown in Figure 2 is joined by heat fusion to end 21a of stub end 11 (described later) of connection structure 3. This heat fusion joint 4 is shown in Figure 1. End 2a of second pipe 2 shown in Figure 2 is joined by heat fusion to end 21a of stub end 12 (described later) of connection structure 3. This heat fusion joint 5 is shown in Figure 1. Note that in Figure 1, the stub end 11 and first pipe 1, and the stub end 12 and second pipe 2 are connected by butt fusion, but they may also be connected via electrofusion joints.

[0025] The first pipe 1 and the second pipe 2 are made of a resin material. A thermoplastic resin is used as the resin material. Specifically, the first pipe 1 and the second pipe 2 are made of a polyolefin such as polyethylene. The resin material for the first pipe 1 and the second pipe 2 may also be polypropylene, PVDF (Polyvinylidene DiFluoride), PVC (polyvinyl chloride), or the like.

[0026] As shown in Figure 2, first pipe 1 and second pipe 2 have flow paths 1b and 2b extending therethrough, each having a circular cross section. Connection structure 3 has flow path 3a extending therethrough, each having a circular cross section. When first pipe 1 and second pipe 2 are connected to connection structure 3, the axes of the flow paths of first pipe 1, second pipe 2, and connection structure 3 are arranged on the same axis O. In connection structure 3, first pipe 1, and second pipe 2, the direction perpendicular to each axis and moving toward or away from each other is defined as the radial direction, and the direction rotating around each axis is defined as the circumferential direction.

[0027] Fig. 3 is a diagram showing a cross-sectional configuration of the connection structure 3. The connection structure 3 has a stub end 11 (an example of a first stub end), a stub end 12 (an example of a second stub end), a packing 13 (an example of a sealing member), a flange 14 (an example of a first flange), and a flange 15 (an example of a second flange). Note that Fig. 3 shows a state in which the packing 13 is not compressed by the stub ends 11 and 12 in order to show the positional relationship of each component.

[0028] Stub end 11 and stub end 12 (an example of a connection object) are arranged opposite each other with packing 13 sandwiched between them. Flange 14 is arranged around stub end 11. Flange 15 is arranged around stub end 12. Flanges 14 and 15 are fastened together by a plurality of bolts 16 and nuts 17. In FIG. 3, bolts 16 and nuts 17 are indicated by two-dot chain lines, showing the configuration on the far side of the page. Bolts 16 and nuts 17 correspond to an example of a fastening part.

[0029] (stub end) The stub ends 11, 12 are made of a resin material. Polyethylene can be used as the resin material. It is more preferable to use high-density polyethylene as the resin material. High-density polyethylene is defined by JIS K 6922-1 and has a density of 0.942 kg / m 3 It is defined as polyethylene having the above properties.

[0030] Since the shapes of the stub end 11 and the stub end 12 are the same, the following description will be given taking the stub end 11 as an example. Fig. 4(a) is a front cross-sectional view of the stub end 11. Fig. 4(a) is a cross-sectional view of the stub end 11 including the axis O. Fig. 4(b) is a bottom view of the stub end 11.

[0031] The stub end 11 has a connection portion 21, an intermediate portion 22, and a flared portion 23 (an example of a joint structure). A flow path 24 is formed in the stub end 11, extending from the connection portion 21, the intermediate portion 22, and the flared portion 23.

[0032] The connecting portion 21 is joined to the end 1a of the first tube 1 by butt welding or fusion via an electrofusion joint. The flared portion 23 presses against the packing 13. The intermediate portion 22 is disposed between the connecting portion 21 and the flared portion 23 (an example of a first end portion) in the axial direction O. The outer diameters of the connecting portion 21, the intermediate portion 22, and the flared portion 23 increase in this order. The flow path 24 is formed from the connecting portion 21 to the flared portion 23.

[0033] The connecting portion 21 is cylindrical and has an end portion 21a where an opening 24a of the flow path 24 is formed. The end portion 21a of the connecting portion 21 is joined to the end 1a of the first pipe 1 by heat fusion.

[0034] The intermediate portion 22 is cylindrical. The intermediate portion 22 is disposed on the opposite side of the end portion 21a of the connecting portion 21. The intermediate portion 22 is formed to have a larger outer diameter than the connecting portion 21. The intermediate portion 22 is formed to have the same inner diameter as the connecting portion 21.

[0035] Flare portion 23 is cylindrical. Flare portion 23 is disposed on the opposite side of intermediate portion 22 from connecting portion 21. Flare portion 23 is formed to have a larger outer diameter than intermediate portion 22. The inner diameter of flare portion 23 is formed to be the same size as intermediate portion 22.

[0036] Flare portion 23 has end surface 23e arranged on the packing 13 side. End surface 23e of flare portion 23 has opening 24b (an example of an opening) of flow path 24, contact surface 23a, and chamfered portion 23b. Opening 24b is formed in the center of end surface 23e of flare portion 23. Opening 24b is arranged opposite opening 24a. Flow path 24 is formed linearly along axis O. Contact surface 23a is formed on end surface 23e of flare portion 23. Contact surface 23a is arranged around opening 24b and contacts packing 13. Contact surface 23a is arranged perpendicular to axis O.

[0037] The chamfered portion 23b is formed around the entire periphery of the edge of the opening 24b. The chamfered portion 23b is disposed between the inner circumferential surface 24c of the flow path 24 and the contact surface 23a. The chamfered portion 23b is formed by C-chamfering the edge of the opening 24b.

[0038] FIG. 5 is a schematic diagram of the stub end 11. FIG. 5 is a cross-sectional view of the stub end 11 including the axis O. For ease of explanation, FIG. 5 has a different shape from FIG. 4. In the cross-sectional view of FIG. 5, if the extension line extending toward the contact surface 23a of the inner circumferential surface 24c of the flow path 24 is L1 and the line on the chamfered portion 23b is L2, and the angle formed by the extension line L1 and the line L2 is θ, θ is set to be equal to or greater than 10 degrees and less than 60 degrees. Note that θ is preferably equal to or greater than 10 degrees and less than 30 degrees.

[0039] Contact surface 23a is connected to chamfered portion 23b at connecting portion 23c. Contact surface 23a and chamfered portion 23b are connected at connecting portion 23c. Connecting portion 23c has a circular shape as shown in FIG. 4(b). The relationship between the inner diameter d1 of connecting portion 23c and the inner diameter d2 of packing 13 will be described after the explanation of packing 13.

[0040] (rubber seal) 3, the packing 13 is disposed between the contact surface 23a of the stub end 11 and the contact surface 23a of the stub end 12. The packing 13 is preferably made of ethylene propylene diene (EPDM) rubber. A portion of the packing 13 is coated with polytetrafluoroethylene (PTFE).

[0041] The packing 13 is formed in an annular plate shape. The outer diameter of the packing 13 is approximately the same as that of the flanges 14 and 15. The inner diameter d2 of the central hole 30 of the packing 13 is set to satisfy the formula 1 described below. The center of the central hole 30 of the packing 13 is positioned on the axis O.

[0042] Fig. 6(a) is a plan view of the packing 13. Fig. 6(b) is a cross-sectional view of the packing 13 taken along line AA in Fig. 6(a). Fig. 6(c) is an enlarged view of part B in Fig. 6(b).

[0043] As shown in FIGS. 6(a) and 6(b), the packing 13 has a flat portion 31, an inner convex portion 32, an outer convex portion 33, an inner convex portion 34, and an outer convex portion 35.

[0044] The flat portion 31 has a main surface 31a on the stub end 11 side and a main surface 31b on the stub end 12 side.

[0045] As shown in FIG. 6(b), the inner convex portion 32 and the outer convex portion 33 are disposed on the main surface 31a. The inner convex portion 32 and the outer convex portion 33 protrude from the main surface 31a along the axis O. The inner convex portion 32 is formed in an annular shape to surround the central hole 30 and is formed concentrically with the central hole 30. The outer convex portion 33 is formed in an annular shape to surround the inner convex portion 32 and is formed concentrically with the central hole 30. The diameter of the inner convex portion 32 is larger than the diameter of the opening 24b of the contact surface 23a of the stub end 11. The diameter of the outer convex portion 33 is smaller than the diameter of the contact surface 23a of the stub end 11. As a result, the inner convex portion 32 and the outer convex portion 33 come into contact with the contact surface 23a of the stub end 11.

[0046] As shown in FIG. 6( b), the inner convex portion 34 and the outer convex portion 35 are disposed on the main surface 31b. The inner convex portion 34 and the outer convex portion 35 protrude from the main surface 31b along the axis O. The inner convex portion 34 is formed in an annular shape to surround the central hole 30 and is formed concentrically with the central hole 30. The outer convex portion 35 is formed in an annular shape to surround the inner convex portion 34 and is formed concentrically with the central hole 30. The diameter of the inner convex portion 34 is larger than the diameter of the opening 24b of the contact surface 23a of the stub end 12. The diameter of the outer convex portion 35 is smaller than the diameter of the contact surface 23a of the stub end 12. As a result, the inner convex portion 34 and the outer convex portion 35 come into contact with the contact surface 23a of the stub end 12.

[0047] The inner convex portion 34 is formed at the same position as the inner convex portion 32 in the radial direction and has the same shape as the inner convex portion 32. The outer convex portion 35 is formed at the same position as the outer convex portion 33 in the radial direction and has the same shape as the outer convex portion 33.

[0048] As shown in FIG. 6(a), the packing 13 has an inner peripheral portion 36 and an outer peripheral portion 37. The inner peripheral portion 36 is a portion of the packing 13 that extends radially outward from the inner edge 13e of the central hole 30. The inner peripheral portion 36 also includes the outer convex portion 33 and the outer convex portion 35. As shown in FIG. 6(c), the inner peripheral portion 36 has a coating portion 36a whose surface is coated with PTFE. The outer peripheral portion 37 is a portion of the packing 13 that is radially outward from the inner peripheral portion 36.

[0049] Four bolt holes 38 are formed in the circumferential direction around the center on the outer periphery 37 of the packing 13. The bolt holes 38 are arranged radially outward from the outer protrusions 33 and 35.

[0050] (Relationship between the inner diameter of the stub end and the inner diameter of the packing) As described above, if the inner diameter of the connection portion 23c is d1 and the inner diameter of the packing 13 described below is d2, the following formula (1) is satisfied. The inner diameter d1 corresponds to the largest inner diameter among the inner diameters of the chamfered portion 23b.

[0051] (Formula 1) 0≦(((d2-d1) / 2) / d2)×100≦1.9 Here, (d2-d1) / 2=d3, and d3 is shown in Figure 7. Figure 7 is a diagram for explaining the length d3. Figure 7 is an enlarged view of the T portion of Figure 3, but in order to explain d3, the position of the inner edge 13e of the packing 13 is different from that of Figure 3.

[0052] 7, the space in the direction perpendicular to the axis O from the inner edge 13e of the central hole 30 of the packing 13 to the connecting portion 23c, which is the edge of the opening 24b, forms the retaining portion S. The length d3 can be said to be the depth of the retaining portion S in the direction perpendicular to the axis O.

[0053] Furthermore, (((d2-d1) / 2) / d2) x 100 represents the ratio of the depth d3 of the stagnation portion S to the packing inner diameter d2. By forming the chamfered portion 23b by performing C-face machining so that this ratio is between 0% and 1.9%, the depth of the stagnation portion S is reduced and the generation of particles is suppressed.

[0054] (flange) As shown in Fig. 3, the flange 14 is disposed radially outward of the stub end 11 and is rotatable relative to the stub end 11. The flange 14 is a loose flange. The flange 15 is disposed radially outward of the stub end 12 and is rotatable relative to the stub end 12. The flange 15 is a loose flange.

[0055] The flanges 14 and 15 are made of a resin material, and it is more preferable that the flanges 14 and 15 are made of glass fiber reinforced polypropylene (GFPP).

[0056] Since flange 14 and flange 15 have the same configuration, flange 14 will be described as an example. Fig. 8(a) is a front view of flange 14. Fig. 8(b) is a cross-sectional view taken along the line CC in Fig. 8(a). Fig. 8(c) is a cross-sectional view taken along the line DD in Fig. 8(a).

[0057] The flange 14 is formed in a disk shape with a diameter larger than that of the flare portion 23 of the stub end 11 .

[0058] The flange 14 has an insertion hole 41 into which the stub end 11 is inserted, and a plurality of bolt holes 42 arranged around the insertion hole 41. The insertion hole 41 and the bolt holes 42 are formed from a surface 43 of the flange 14 facing the packing 13 to a surface 44 opposite the packing 13. In this embodiment, four bolt holes 42 are formed.

[0059] The insertion hole 41 has a large diameter portion 45 and a small diameter portion 46 with different inner diameters. The large diameter portion 45 is formed along the axis O from the surface 43 of the flange 14. The flared portion 23 of the stub end 11 is disposed in the large diameter portion 45. The small diameter portion 46 is disposed on the surface 44 side of the large diameter portion 45. The small diameter portion 46 is formed from the large diameter portion 45 to the surface 44. The intermediate portion 22 of the stub end 11 is disposed in the small diameter portion 46. As shown in FIG. 3 , the contact surface 23a of the stub end 11 protrudes slightly toward the packing 13 beyond the surface 43 of the flange 14. In this embodiment, the contact surface 23a of the stub end 11 protrudes slightly toward the packing 13 beyond the surface 43 of the flange 14, and the outer edge 23f of the stub end 11 protrudes slightly toward the packing 13 beyond the surface 43 of the flange 14. The positional relationship between the contact surface 23a of the stub end 12 and the surface 43 of the flange 14 is also similar.

[0060] The flange 14 has a plurality of ribs 48 formed on the surface 44 and a plurality of recesses 47 formed on the surface 44. The ribs 48 are arranged between the bolt holes 42 in the circumferential direction. The ribs 48 are arranged along the diameter direction. The ribs 48 are provided for reinforcement. In this embodiment, four ribs 48 are formed. The recesses 47 are arranged on both sides of each rib 48 in the circumferential direction. The recesses 47 are lightening portions.

[0061] The flanges 14 and 15 are arranged so that their surfaces 43 face each other.

[0062] (Assembly of connection structure 3) The stub end 11 is inserted into the insertion hole 41 of the flange 14 , and the stub end 12 is inserted into the insertion hole 41 of the flange 15 .

[0063] Packing 13 is disposed between contact surface 23a of stub end 11 and contact surface 23a of stub end 12. Bolts 16 are inserted into bolt holes 42 of flange 14, bolt holes 38 of packing 13, and bolt holes 42 of flange 15. In this embodiment, four bolts 16 are inserted.

[0064] Nut 17 is screwed onto the tip of inserted bolt 16. This fastens flange 14 and flange 15 together, and packing 13 is pressed against stub end 11 and stub end 12.

[0065] The flow path 3 a of the connection structure 3 is formed by the flow path 24 of the stub end 11 , the central hole 30 of the packing 13 , and the flow path 24 of the stub end 12 .

[0066] FIG. 9 is a diagram showing a state in which packing 13 is pressed against stub end 11 and stub end 12. As described above, chamfered portion 23b is formed so that 0≦(((d2−d1) / 2) / d2)×100≦1.9. This reduces difference d3 (see FIG. 7) between the position of inner edge 13e of packing 13 and the position of connecting portion 23c in a direction perpendicular to axis O, making it difficult for stagnation portion S (see FIG. 7) to be formed. Furthermore, in a cross section including central axis O of flow path 24, angle θ formed between extension line L1 of inner circumferential surface 24c and line L2 on chamfered portion 23b is 10 degrees or more and less than 60 degrees. This reduces difference d3 (see FIG. 7) between the position of inner edge 13e of packing 13 and the position of connecting portion 23c in a direction perpendicular to axis O, making it difficult for stagnation portion S (see FIG. 7) to be formed.

[0067] (Ultrapure water application for connection structure 3) The joint structure and connection structure 3 according to the embodiment of the present disclosure can be used, for example, for transporting ultrapure water. Specifically, the joint structure and connection structure 3 for ultrapure water according to the embodiment of the present disclosure can be used as piping within an ultrapure water production apparatus, piping for transporting ultrapure water from an ultrapure water production apparatus to a use point, piping for returning ultrapure water from a use point, etc.

[0068] Ultrapure water is water with extremely high purity, and is suitable for use in cleaning electronic devices such as semiconductor devices. There are many indices for expressing the grade of ultrapure water, but in this embodiment, the electrical resistivity of ultrapure water is 18.2 MΩ cm or more, and the TOC is 50 ppb or less.

[0069] The joint structure and connection structure 3 of the embodiment according to the present disclosure are preferably used for water piping for nuclear power generation, which has particularly strict requirements for the quality of ultrapure water, or for transporting ultrapure water used in wet processing steps such as cleaning in the manufacturing process of pharmaceuticals, semiconductor devices, or liquid crystals, more preferably semiconductor devices. The semiconductor devices in question are preferably those with a high degree of integration, and more specifically, those used in the manufacturing process of semiconductor devices with a minimum line width of 65 nm or less. Standards for the quality of ultrapure water used in semiconductor manufacturing include, for example, SEMI F75.

[0070] (Features, etc.) In the joint structure of this embodiment, the angle θ formed between the drawn line L1 of the inner circumferential surface 24c and the line L2 on the chamfered portion 23b in a cross section including the central axis O of the flow path 24 is 10 degrees or more and less than 60 degrees.

[0071] This reduces the difference in position between inner edge 13e of packing 13 and connecting portion 23c in the direction perpendicular to axis O, making it difficult for retention portion S (see FIG. 12) to form in inner portion P of inner edge 13e. In this way, the difference in inner diameter between packing 13 and stub ends 11, 12 can be reduced, suppressing particle retention and improving the yield of semiconductor products, particularly in the field of semiconductor manufacturing.

[0072] Furthermore, in the joint structure of this embodiment, if the inner diameter of the connection portion 23c between the contact surface 23a and the chamfered portion 23b is d1 and the inner diameter of the packing 13 is d2, then the relationship 0≦(((d2−d1) / 2) / d2)×100≦1.9 is satisfied.

[0073] This reduces the difference in position between inner edge 13e and connecting portion 23c of packing 13 in the direction perpendicular to axis O, making it difficult for retention portion S (see FIG. 12) to form in inner portion P of inner edge 13e. This makes it possible to suppress retention of particles, which can improve the yield of semiconductor products, particularly in the field of semiconductor manufacturing.

[0074] (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.

[0075] (A) In the above embodiment, the stub end 11 and the stub end 12 have the same configuration, but they may be different as long as the chamfered portion 23b is formed on the edge of the opening 24b.

[0076] (B) In the above embodiment, both the flange 14 and the flange 15 are loose flanges that can rotate relative to the stub end, but either one of them may be a flange that is fixed to the stub end.

[0077] (C) In the above embodiment, the flange 14 and the flange 15 are fastened together by four bolts 16, but the number is not limited to four.

[0078] (D) In the above embodiment, the packing 13 has inner convex portions 32, 34 and outer convex portions 33, 35, but further annular convex portions may be formed outside the outer convex portions 33, 35, or the outer convex portions 33, 35 may not be formed.

[0079] (E) In the above embodiment, the gasket 13 is made of ethylene propylene diene (EPDM) rubber and is partially coated with polytetrafluoroethylene (PTFE), but this is not limited to this and, for example, it may be made of only one of the two.

[0080] Furthermore, the packing 13 is not limited to being made of polyolefin, but may be made of PVC (polyvinyl chloride) or PVDF (polyvinylidene fluoride).

[0081] (F) In the above embodiment, a packing has been described as an example of a sealing member of the present disclosure, but the sealing member is not limited to a packing and may be a gasket or an O-ring.

[0082] (G) In the above embodiment, the flared portion 23 of the stub end 11 was described as an example of a connection structure of the present disclosure, but this is not limited to stub ends and may be applied to the flange portions of valves such as diaphragm valves, ball valves, and ball catch valves. The chamfered portion described in the above embodiment can be provided on the edge of the opening of the flow path formed in the flange portion of the valve.

[0083] (Example) The above-described embodiment will be described in detail below using examples.

[0084] By the C-face machining described in the above embodiment, it is possible to reduce the difference in inner diameter between the packing 13 and the opening 24a of the stub end 11 for each of the six diameters shown in Table 1 below.

[0085] For each diameter in the examples shown below (Table 1), the stub end was created with θ=30°.

[0086] As a comparative example, a case where no C-face machining is performed is also shown. The configuration of stub end 1011 when no C-face machining is performed is shown in Fig. 10. The inner diameter d1 of opening 1024b in stub end 1011 is the same as the inner diameter of flow path 1024 because no C-face machining is performed.

[0087] (Table 1) TIFF2025153711000002.tif71167As in the above examples, by performing C-face machining, the difference in inner diameter between the packing 13 and the opening 24a of the stub end 11 can be reduced, and the size of the retention portion S can be suppressed.

[0088] Next, a simulation was conducted to examine the occurrence of retention in the retention section S by changing the chamfering angle θ. For a nominal diameter of 150A, a simulation of retention was conducted using a stub end (inner diameter D1 = 140.6 mm) and packing (d2 = 150 mm). The simulation was conducted using the Ansys Fluent turbulent flow analysis K-ω SST model. The inner diameter D1 of the stub end is the inner diameter of the flow path 24 in Figure 5 (inner diameter of opening 24a).

[0089] 11(a) is a diagram illustrating the configurations of an example and a comparative example in which a simulation was performed. In the example, the simulation was performed using the stub ends 11 and 12 described above in the embodiment. The stub ends 11 and 12 have the same shape. If the length from the inner edge 13e of the packing 13 of the stub end 11 to the inner circumferential surface 24c of the flow path 24 is d4 and the distance between the contact surface 23a of the stub end 11 and the contact surface 23a of the stub end 12 is d5, then d4 = 4.7 mm and d5 = 3.6 mm were set.

[0090] 11(a), the length from the inner edge 13e of the packing 13 toward the inner diameter of the stub end 11 to the connection portion 23c is defined as d6, and d6 was set to 2.9 mm. As an example, a simulation was performed assuming stub ends machined at θ = 10 degrees and 30 degrees from the position of d6 (= 2.9 mm). As comparative examples, a simulation was performed assuming stub ends machined at θ = 60 degrees and 80 degrees.

[0091] Here, the groove area is defined as the area enclosed by line L1', which is an extension of line L1 shown in FIG. 5 and connects the inner circumferential surface 24c of the flow passage 24 of stub end 11 with the inner circumferential surface 24c of the flow passage 24 of stub end 12, inner edge 13e, contact surface 23a and chamfered portion 23b of stub end 11, and contact surface 23a and chamfered portion 23b of stub end 12. In FIG. 11(a), the groove area is the region indicated by dots. Of this groove area, the retention area, which is the portion where retention occurs through simulation, was calculated, and the ratio of the retention area to the groove area ((retention area / groove area) × 100) (%) was calculated. The results are shown in Table 2.

[0092] Also, Figure 11(b) is a diagram showing the configuration of a stub end of a comparative example where θ = 0 degrees. In the comparative example shown in Figure 11(b), the packing 13 is sandwiched between the stub end 1011 shown in Figure 10. In the comparative example shown in Figure 11(b), no C-chamfering is performed. The groove area is d4 x d5, which is 3.6 x 4.7 = 16.92 mm 2 This becomes:

[0093] (Table 2) TIFF2025153711000003.tif46167At θ = 10 degrees and 30 degrees, the proportion of the water retention area to the total groove volume was reduced by about 30 to 40%, but no reduction in the retention area was confirmed in other areas.

[0094] This shows that the retention portion can be reduced by chamfering the surface so that θ is in the range of 10 degrees or more and less than 60 degrees.

[0095] Furthermore, it is clear that the retention portion can be reduced by C-chamfering, and therefore it is also clear from Table 1 that the retention portion can be reduced in the examples.

[0096] As a result, the generation of vortexes due to stagnation can be suppressed, and the generation of particles after water passes through the piping can be suppressed. [Explanation of symbols]

[0097] 11: Stub end 23: Flare section 23a: Contact surface 23b: Chamfered part 24: Flow path 24c: Inner surface

Claims

1. A joint structure used for connecting pipes and formed of a resin material, a flow path through which a liquid flows; a contact surface that is disposed around an opening of the flow path and that comes into contact with a seal member that is disposed between the connection object and the contact surface; a chamfered portion formed on an edge of the opening by C-chamfering and disposed between an inner circumferential surface of the flow path and the contact surface, an angle formed by the drawing line of the inner circumferential surface and the line on the chamfered portion in a cross section including the central axis of the flow channel is 10 degrees or more and less than 60 degrees; Joint structure.

2. A joint structure used for connecting pipes and formed of a resin material, a flow path through which a liquid flows; a contact surface that is disposed around an opening of the flow path and that comes into contact with a seal member that is disposed between the connection object and the contact surface; a chamfered portion formed on an edge of the opening by C-chamfering and disposed between an inner circumferential surface of the flow path and the contact surface, When the inner diameter of the connection portion between the contact surface and the chamfered portion is d1 and the inner diameter of the seal member is d2, the relationship 0≦(((d2−d1) / 2) / d2)×100≦1.9 is satisfied. Joint structure.

3. The resin material is polyethylene. The joint structure according to claim 1 or 2.

4. The polyethylene is a high-density polyethylene. The joint structure according to claim 3.

5. The joint structure is used for semiconductor cleaning applications. The joint structure according to claim 1 or 2.

6. A first stub end having the joint structure according to claim 1 or 2; A second stub end having the joint structure according to claim 1 or 2; a seal member disposed between the contact surface of the first stub end and the contact surface of the second stub end; a first flange disposed around the first stub end; a second flange disposed about the second stub end; and a fastening portion for fastening the first flange and the second flange together. Connection structure.

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