Diaphragm valve and manufacturing method thereof

Abstract

The purpose of the present invention is to provide a diaphragm valve and a manufacturing method for suppressing the generation of particles, the diaphragm valve (1A) comprising: a diaphragm (3) having a valve body part (3a) and a diaphragm part (3b) that extends outward from the valve body part and is deformable in the direction of a movement axis (C); and a main body (5) having a valve seat section (5a) in which the valve body section that reciprocates in the direction of the movement axis comes into contact with and separates from each other, one of the valve body section and the valve seat section being provided with a rib (31) that protrudes toward the other, the rib being configured from crosslinked PFA from the tip thereof to the root thereof, the tertiary carbon concentration M1 (mol%) at the tip and the tertiary carbon concentration M2 (mol%) at the root satisfy M1 > = 0.01, M2 > = 0.01, and 0.8 < = M1 / M2 < = 1.2. The present invention is provided with: a step for obtaining a cut sheet of a cross-linked PFA film which is cross-linked so that the tertiary carbon concentration is 0.01 mol% or more; re-molding the cut sheet to obtain a re-molded object; and obtaining a rib from the reformed object.

Description

Technical Field

[0001] This invention relates to diaphragm valves and methods for manufacturing the same. More specifically, it relates to diaphragm valves having a diaphragm for fluid control and methods for manufacturing the same. Background Technology

[0002] Diaphragm valves can be used to control various fluids under various conditions, such as controlling the flow and volume of pharmaceutical solutions used in semiconductor manufacturing. In this case, the diaphragm valve comprises a body and a diaphragm made of fluoropolymers such as polytetrafluoroethylene (PTFE) and perfluoroalkoxyalkylene (PFA) to ensure excellent chemical resistance and flexural durability. The body has a valve chamber communicating with multiple flow paths, and the diaphragm can reciprocate within the valve chamber along its axis of movement. Thus, a mechanism is established whereby, when the diaphragm reciprocates, the valve core portion located at the lower end of the diaphragm abuts against / separates from the valve seat portion located at the flow path opening within the valve chamber. This abutment / separation opens / closes the flow path containing the valve seat portion and changes the size of the flow path.

[0003] In such diaphragm valves, preventing the generation of particles during the contact / separation of the valve core and valve seat becomes a problem. Specifically, particles can be defined as particles resulting from the miniaturization of the materials forming the components of the diaphragm valve due to wear, etc. If particles are generated in the valve core and valve seat, located in the wetted area, they will mix into the cleaning solution flowing within the diaphragm valve. Therefore, in cases where the cleaning solution is, for example, a cleaning solution used in semiconductor manufacturing, the presence of particles in the cleaning solution leads to a reduction in cleaning effectiveness. To address this problem, the technology described in Patent Document 1 is known.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2023-034749 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The aforementioned patent document 1 discloses a flow control valve with the aim of reducing dust generation due to its excellent wear resistance: the flow path side body and valve core are formed by a fluoropolymer composed of PFA or PTFE, and an annular or circular sealing member composed of cross-linked PTFE is joined at the valve core side abutment and the valve seat side abutment.

[0009] However, cross-linked PTFE is harder than non-cross-linked PTFE and PFA. Therefore, when the valve core, whose surface is formed only by cross-linked PTFE, comes into contact with / separates from the valve seat, the non-cross-linked part deforms. This creates a sliding area on the surface of the valve core and the surface of the valve seat. As a result, particles can still be generated in this sliding area.

[0010] The present invention was made in view of the above-mentioned actual situation, and its object is to provide a diaphragm valve and a method thereof that can further suppress the generation of particles compared with existing diaphragm valves.

[0011] Technical solution

[0012] That is, the present invention includes the following contents.

[0013] [1] A diaphragm valve comprising: a diaphragm having a valve core portion and a membrane portion extending outwardly from the valve core portion and deformable in a direction of a moving axis; and a body having a valve seat portion for contacting and separating from the valve core portion, which reciprocates in the direction of the moving axis due to deformation of the membrane portion, the diaphragm valve being characterized in that...

[0014] A rib protruding towards the other is provided on either the valve core or the valve seat.

[0015] The ribs are composed of cross-linked PFA from their tip to their root.

[0016] When the concentration of tertiary carbon at the top is set to M1 (mol%) and the concentration of tertiary carbon at the root is set to M2 (mol%), the following conditions must be met: M1≥0.01, M2≥0.01 and 0.8≤M1 / M2≤1.2.

[0017] [2] According to the diaphragm valve described in [1] above, wherein,

[0018] The component that is either the diaphragm or the body and has the rib has:

[0019] The base is composed of a non-crosslinked fluoropolymer; and

[0020] The end portion is integrated relative to the base portion, has the rib, and is composed of the cross-linked PFA.

[0021] [3] According to the diaphragm valve described in [1] or [2] above, wherein,

[0022] The distance between the top end and the root of the rib is greater than or equal to 250 μm.

[0023] [4] The diaphragm valve according to any one of [1] to [3] above, wherein,

[0024] The valve core or the valve seat has a contact portion that abuts against the rib provided on the component of said one.

[0025] The contact portion is made of cross-linked fluoropolymer.

[0026] [5] The diaphragm valve according to any one of [1] to [4] above, wherein,

[0027] The rib is composed of a reshaped piece of a cross-linked PFA film, which is cross-linked in such a manner that the concentration of tertiary carbon is greater than or equal to 0.01 mol%.

[0028] [6] According to the diaphragm valve described in [2] above, wherein,

[0029] One of the components is cut from a composite, which is an integral part of a cut piece of a cross-linked PFA film that will become the base, consisting of an intermediate made of non-crosslinked fluoropolymer resin and a crosslinked PFA film with a tertiary carbon concentration of ≥0.01 mol%.

[0030] [7] A method for manufacturing a diaphragm valve, wherein the method for manufacturing the diaphragm valve is any one of the methods for manufacturing the diaphragm valve described in any one of [1] to [6] above, characterized in that it comprises:

[0031] The cutting process yields a cut sheet of a cross-linked PFA film formed by cross-linking in a manner that ensures a tertiary carbon concentration of ≥0.01 mol%.

[0032] The reshaping process reshapes the cut pieces to obtain a reshaped article; and

[0033] The forming process involves obtaining the rib from the reshaped material.

[0034] [8] According to the manufacturing method of the diaphragm valve described in [7] above, wherein,

[0035] The method for manufacturing the diaphragm valve includes: an integrated process to obtain a composite material formed by integrating an intermediate component made of non-crosslinked fluororesin and the remolded material.

[0036] [9] According to the manufacturing method of the diaphragm valve described in [8] above, wherein,

[0037] The integrated process includes: a cut piece receiving process, in which the cut piece is received in a cavity provided in the intermediate component; and

[0038] In the firing process, the cut piece is melted inside the cavity to obtain the reshaped article, and the intermediate part is integrated with the reshaped article.

[0039]

[10] The method for manufacturing a diaphragm valve according to [8] or [9] above, wherein,

[0040] The integration process includes: an injection molding process, in which molten material of the cut piece is injected into a cavity of the intermediate part to obtain the reshaped part within the cavity, and the intermediate part and the reshaped part are integrated.

[0041]

[11] A method for manufacturing a diaphragm valve according to any one of [8] to

[10] above, wherein,

[0042] The integrated process includes: a cut piece receiving process, in which the cut piece is received in a cavity provided in the intermediate component; and

[0043] In the compression molding process, the cut piece is compressed within the cavity to obtain the reshaped article, and the intermediate part is integrated with the reshaped article.

[0044]

[12] A method for manufacturing a diaphragm valve according to any one of [7] to

[11] above, wherein,

[0045] The method for manufacturing the diaphragm valve includes: a welding process to obtain a composite material formed by welding an intermediate component made of non-crosslinked fluororesin to the pre-obtained remolded material.

[0046] Invention Effects

[0047] The diaphragm valve according to the present invention can further suppress particle generation compared to existing diaphragm valves.

[0048] In a diaphragm valve where the ribs are composed of cross-linked PFA from tip to root, and the tertiary carbon concentration M1 (mol%) at the tip and the tertiary carbon concentration M2 (mol%) at the root satisfy M1 ≥ 0.01, M2 ≥ 0.01, and 0.8 ≤ M1 / M2 ≤ 1.2, the ribs are formed from fully cross-linked PFA from tip to root. Therefore, deformation of the ribs is prevented when one component with ribs comes into contact with the other component. Thus, compared to diaphragm valves that do not satisfy the above-mentioned M1 and M2 relationships, the diaphragm valve of the present invention can suppress particle generation.

[0049] In the aforementioned diaphragm valve, the component having ribs, either as the diaphragm or the body, can have: a base made of non-crosslinked fluoropolymer; and an end portion integral with respect to the base, having ribs and made of crosslinked PFA. In this case, a non-crosslinked fluoropolymer with superior flexural durability compared to crosslinked PFA can be used as the base, thus particularly enabling excellent flexural durability of the membrane portion of the diaphragm. Furthermore, since it is not necessary to form the diaphragm or body integrally from crosslinked PFA, the manufacturing cost of the diaphragm valve can be reduced.

[0050] In the diaphragm valve described above, the distance D1 between the top end 31a and the root 31b of rib 31 can be defined as follows (refer to...). Figure 2The rib spacing is greater than or equal to 250 μm. Generally, it is difficult from the viewpoint of radiation transmittance to crosslink a thick layer of non-crosslinked PFA in a manner that extends across both the surface and back, but this can be achieved through the diaphragm valve manufacturing method described later. Furthermore, by having ribs with a spacing greater than or equal to 250 μm, reliable flow control can be achieved compared to ribs with a spacing less than 250 μm.

[0051] In the aforementioned diaphragm valve, either the valve core or the valve seat may have a contact portion that abuts against a rib provided on one of the components, and this contact portion is formed of cross-linked fluoropolymer. In this case, using cross-linked fluoropolymer with excellent wear resistance as the material allows for the manufacture of a diaphragm valve with superior durability.

[0052] In the aforementioned diaphragm valve, the ribs can be constructed from remolded pieces of cross-linked PFA membranes with a tertiary carbon concentration greater than or equal to 0.01 mol%. That is, it is difficult from a radiation transmittance perspective to cross-link a thick, non-cross-linked PFA membrane entirely across its surface and back with a tertiary carbon concentration greater than or equal to 0.01 mol%, but by irradiating a non-cross-linked PFA membrane of sufficient thickness to achieve this cross-linking, a cross-linked PFA membrane with a tertiary carbon concentration greater than or equal to 0.01 mol% can be obtained. If a component is constructed from cross-linked PFA obtained by remolding pieces of this cross-linked PFA membrane, a cross-linked PFA component with uniform cross-linking can be manufactured regardless of its thickness. By forming the ribs from such a cross-linked PFA component with uniform cross-linking, deformation of the ribs themselves can be prevented, thus significantly suppressing particle generation associated with the contact / separation of the valve core and valve seat.

[0053] In the aforementioned diaphragm valve, one component can be cut from a composite material, which is an integrally formed piece of a cross-linked PFA membrane cut from a non-crosslinked fluoropolymer resin that will serve as the base, and a cross-linked PFA membrane with a tertiary carbon concentration of ≥0.01 mol%. In this case, a non-crosslinked fluoropolymer resin with superior flexural durability compared to crosslinked PFA can be used as the base, thus particularly improving the flexural durability of the membrane portion of the diaphragm. Furthermore, since it is not necessary to form the diaphragm or body integrally from crosslinked PFA, the manufacturing cost of the diaphragm valve can be reduced.

[0054] The method for manufacturing a diaphragm valve according to the present invention provides a method for manufacturing a diaphragm valve that can further suppress the generation of particles compared to existing diaphragm valves.

[0055] By incorporating a cutting process for obtaining a cut sheet of a cross-linked PFA film with a tertiary carbon concentration of ≥0.01 mol%, a remolding process for remolding the cut sheet to obtain a remolded product, and a rib-forming process for obtaining ribs from the remolded product, a cross-linked PFA film with a uniform cross-linking concentration of ≥0.01 mol% can be obtained. Furthermore, by remolding the cut sheet of this uniformly cross-linked PFA film, a remolded product (cross-linked PFA member) composed of cross-linked PFA with a uniform overall tertiary carbon concentration of ≥0.01 mol% can be obtained. By forming ribs from such a cross-linked PFA member with a uniform overall cross-linking degree, deformation of the ribs themselves can be prevented, thus enabling a diaphragm valve that significantly suppresses particle generation accompanying the contact / separation of the valve core and valve seat.

[0056] The aforementioned method for manufacturing a diaphragm valve includes an integrated process to obtain a composite component formed by integrating an intermediate part made of non-crosslinked fluoropolymer resin with a remolded part. In this case, a non-crosslinked fluoropolymer resin with superior flexural durability compared to crosslinked PFA can be used. Therefore, the membrane portion of the diaphragm can be formed through the intermediate part of the composite component, resulting in excellent flexural durability of the membrane portion. Furthermore, since it is not necessary to form the diaphragm or the main body integrally from crosslinked PFA, the manufacturing cost of the diaphragm valve can be reduced.

[0057] In the above-described method for manufacturing a diaphragm valve, the integration process may include: a cut-piece receiving process, in which a cut-piece is received in a cavity provided in an intermediate part; and a firing process, in which the cut-piece is melted in the cavity to obtain a reshaped article, and the intermediate part and the reshaped article are integrated. Alternatively, in the above-described method for manufacturing a diaphragm valve, the integration process may include: an injection molding process, in which molten material of the cut-piece is injected into a cavity provided in an intermediate part, a reshaped article is obtained in the cavity, and the intermediate part and the reshaped article are integrated. Alternatively, in the above-described method for manufacturing a diaphragm valve, the integration process may include: a cut-piece receiving process, in which a cut-piece is received in a cavity provided in an intermediate part; and a compression molding process, in which the cut-piece is compressed in the cavity to obtain a reshaped article, and the intermediate part and the reshaped article are integrated. Furthermore, in the above-described method for manufacturing a diaphragm valve, a welding process may be included, in which a composite part is obtained by welding an intermediate part made of non-crosslinked fluororesin to a pre-obtained reshaped article. By incorporating these processes, a composite part can be obtained that integrates an intermediate component made of non-crosslinked fluoropolymer with a remolded part. Therefore, as described above, a diaphragm can be obtained that has ribs formed entirely of uniformly crosslinked PFA on one side and a membrane portion with excellent flexural durability on the other. Furthermore, since it is not necessary to form the diaphragm or the main body entirely from crosslinked PFA, the manufacturing cost of the diaphragm valve can be reduced. Attached Figure Description

[0058] The invention will be further described in the following detailed description with reference to the numerous accompanying drawings, which list non-limiting examples of typical embodiments of the invention, though in some of the drawings the same reference numerals denote the same parts.

[0059] Figure 1 This is a longitudinal sectional view of the diaphragm valve in Example 1.

[0060] Figure 2 This is a longitudinal sectional view of the diaphragm that makes up the diaphragm valve.

[0061] Figure 3 This is a longitudinal sectional view of the main body that makes up the diaphragm valve.

[0062] Figure 4 This is a diagram illustrating the function of a diaphragm valve. Figure 4 (a) indicates the valve is closed. Figure 4 (b) indicates the valve is open.

[0063] Figure 5 This is an explanatory diagram illustrating the manufacturing method of a diaphragm valve. Figure 5 (a) represents a cross-linked PFA membrane. Figure 5 (b) indicates the cutting process of the cross-linked PFA film. Figure 5 (c) indicates the re-forming process of cut pieces of cross-linked PFA film.

[0064] Figure 6 This is an explanatory diagram illustrating the manufacturing method of a diaphragm valve (the integrated process of intermediate parts and remolded parts). Figure 6 (a) represents a three-dimensional view of the intermediate part and the reshaped part. Figure 6 (b) shows a longitudinal sectional view of the case where the reshaped part is contained in the cavity of the intermediate part.

[0065] Figure 7 This is an explanatory diagram illustrating the manufacturing method of a diaphragm valve (the rib formation process). Figure 7 (a) represents a longitudinal sectional view of the composite component. Figure 7 (b) shows a longitudinal sectional view of the diaphragm obtained by cutting the composite.

[0066] Figure 8 This is an explanatory diagram illustrating the manufacturing method (rib formation process) of other types of diaphragm valves. Figure 8 (a) represents a longitudinal sectional view of the composite component. Figure 8 (b) shows a longitudinal sectional view of the diaphragm obtained by cutting the composite.

[0067] Figure 9 This is an explanatory diagram illustrating a manufacturing method (rib formation process) for yet another type of diaphragm valve. Figure 9 (a) represents a longitudinal sectional view of the composite component. Figure 9 (b) shows a longitudinal sectional view of the diaphragm obtained by cutting the composite.

[0068] Figure 10 This is an explanatory diagram illustrating a manufacturing method (rib formation process) for yet another type of diaphragm valve. Figure 10 (a) represents a longitudinal sectional view of the composite component. Figure 10 (b) shows a longitudinal sectional view of the diaphragm obtained by cutting the composite.

[0069] Figure 11 This is an explanatory diagram illustrating a different method of manufacturing a diaphragm valve (an integrated process of intermediate parts and remolded parts).

[0070] Figure 12 This is a longitudinal sectional view of the diaphragm valve in Example 2.

[0071] Figure 13 This is a longitudinal sectional view of the diaphragm that makes up the diaphragm valve.

[0072] Figure 14 This is a longitudinal sectional view of the main body that makes up the diaphragm valve.

[0073] Figure 15 This is a diagram illustrating the function of a diaphragm valve. Figure 15 (a) indicates the valve is closed. Figure 15 (b) indicates the valve is open.

[0074] Figure 16 This is an explanatory diagram illustrating the manufacturing method of a diaphragm valve. Figure 16 (a) represents a cross-linked PFA membrane. Figure 16 (b) indicates the cutting process of the cross-linked PFA film. Figure 16 (c) indicates the re-forming process of cut pieces of cross-linked PFA film.

[0075] Figure 17 This is an explanatory diagram illustrating the manufacturing method of a diaphragm valve (the integrated process of intermediate parts and remolded parts). Figure 17 (a) represents a three-dimensional view of the intermediate part and the reshaped part. Figure 17 (b) shows a longitudinal sectional view of the case where the reshaped part is contained in the cavity of the intermediate part.

[0076] Figure 18 This is an explanatory diagram illustrating the manufacturing method of a diaphragm valve (the rib formation process). Figure 18 (a) represents a longitudinal sectional view of the composite component. Figure 18 (b) represents a longitudinal sectional view of the main body obtained by cutting the composite.

[0077] Figure 19 This is an explanatory diagram illustrating the manufacturing method (rib formation process) of other types of diaphragm valves. Figure 19 (a) represents a longitudinal sectional view of the composite component. Figure 19 (b) represents a longitudinal sectional view of the main body obtained by cutting the composite.

[0078] Figure 20 This is an explanatory diagram illustrating a manufacturing method (rib formation process) for yet another type of diaphragm valve. Figure 20 (a) represents a longitudinal sectional view of the composite component. Figure 20 (b) represents a longitudinal sectional view of the main body obtained by cutting the composite.

[0079] Figure 21 This is an explanatory diagram illustrating a manufacturing method (rib formation process) for yet another type of diaphragm valve. Figure 21 (a) represents a longitudinal sectional view of the composite component. Figure 21 (b) represents a longitudinal sectional view of the main body obtained by cutting the composite.

[0080] Figure 22 This is an explanatory diagram illustrating a manufacturing method (rib formation process) for yet another type of diaphragm valve. Figure 22 (a) represents a longitudinal sectional view of the composite component. Figure 22 (b) represents a longitudinal sectional view of the main body obtained by cutting the composite.

[0081] Figure 23 This is an explanatory diagram illustrating a different method of manufacturing a diaphragm valve (an integrated process of intermediate parts and remolded parts). Detailed Implementation

[0082] The matters illustrated herein are exemplary and intended to illustrate embodiments of the invention. They are described with the aim of providing a description that is thought to most effectively and readily convey the principles and conceptual features of the invention. In this respect, it is not intended to show structural details of the invention beyond what is necessary for a fundamental understanding of the invention, but rather to clarify to those skilled in the art how some aspects of the invention are actually embodied through description in conjunction with the accompanying drawings.

[0083] The present invention will now be described in detail with reference to the accompanying drawings and through Embodiments 1 and 2.

[0084] <Example 1>

[0085] like Figure 1As shown, the diaphragm valve 1A of this embodiment includes: a diaphragm 3 having a valve core portion 3a and a membrane portion 3b extending outward from the valve core portion 3a and deformable in the direction of the moving axis C; and a body 5 having a valve seat portion 5a, which is used to abut and separate the valve core portion 3a, which reciprocates in the direction of the moving axis C due to the deformation of the membrane portion 3b (see reference). Figure 4 Furthermore, the diaphragm valve 1A includes a drive unit 7 for driving the diaphragm 3.

[0086] In the main body 5, a valve chamber 11 is formed at the upper center, and a first flow path and a second flow path communicating with the valve chamber 11 are formed. Furthermore, in the main body 5, an annular valve seat portion 5a is formed around the opening from the first flow path to the valve chamber 11 for the diaphragm 3 (specifically, the valve core portion 3a) to abut / separate. In this embodiment, as the first flow path, an inlet flow path 13 is formed extending from a flow inlet 12 formed on one of the opposite sides of the main body 5 and opening at the center of the bottom of the valve chamber 11. The valve seat portion 5a is formed around the opening from the inlet flow path 13 to the valve chamber 11. Furthermore, as the second flow path, an outlet flow path 15 is formed extending from a flow outlet 14 formed on the other opposite side of the main body 5 and opening on the side of the valve chamber 11. However, the first and second flow paths are not limited to the methods described above. For example, a weir portion for diaphragm contact / separation can be provided between each flow path, or each flow path can be configured in a straight line. Furthermore, in this embodiment, the first and second flow paths are connected to the valve chamber 11, but the flow paths connected to the valve chamber 11 are not limited to this, and there may be more than three flow paths.

[0087] The drive unit 7 is mounted on the upper part of the main body 5. Furthermore, the drive unit 7 includes: a drive unit housing 17, which has a mechanism receiving space formed inside; a cover member 18, mounted on the upper part of the drive unit housing 17; a valve stem 19 connected to the diaphragm 3; and a drive mechanism, housed in the mechanism receiving space and driving the valve stem 19. In this embodiment, a cylinder is formed within the drive unit housing 17 as the mechanism receiving space, and the drive mechanism consists of a piston 21 housed within the cylinder and a coil spring 22 serving as a force-applying member.

[0088] The piston 21 includes a piston body 21a, which is slidably housed within the cylinder of the drive housing 17; and a guide shaft 21b extending upward from the piston body 21a. A valve stem 19 is connected to the piston body 21a, extending downward from it. The outer peripheral surface of the piston body 21a contacts the inner peripheral surface of the cylinder in a vertically slidable manner. The piston body 21a divides the internal space of the cylinder into an upper space S1 enclosed by the upper surface of the piston body 21a, the inner peripheral wall of the cylinder, and the top surface of the cylinder (i.e., the lower surface of the cover member 18), and a lower space S2 enclosed by the lower surface of the piston body 21a, the inner peripheral wall of the cylinder, and the bottom surface of the cylinder (i.e., the bottom of the drive housing 17). The guide shaft 21b is slidably inserted into a through hole provided through the cover member 18, guiding the vertical movement of the piston 21. The valve stem 19 is slidably inserted into a through hole provided at the bottom of the drive housing 17 and extends to the valve chamber 11, with its top end connected to the diaphragm 3.

[0089] A vent 26 is formed on the cover member 18, communicating with the cylinder portion that divides the upper space S1. Ventilation can be achieved between the upper space S1 and the outside through the vent 26. Furthermore, a working fluid supply port 27 is formed on the side of the drive housing 17, communicating with the bottom of the cylinder portion that divides the lower space S2. Working fluid can be supplied into the lower space S2 from the working fluid supply port 27. Moreover, a coil spring 22 is disposed in a compressed state between the lower surface of the cover member 18 (i.e., the top surface of the cylinder portion) and the upper surface of the piston body 21a.

[0090] It should be noted that the drive unit 7 is not limited to driving the diaphragm 3 using fluid pressure as described above. For example, it can also be driven by an electric actuator equipped with a motor, solenoid, etc. Moreover, it can also be driven manually.

[0091] The diaphragm 3 is configured to block the opening above the valve chamber 11 and is fixed to the main body 5. Furthermore, the diaphragm 3 has: a valve core portion 3a located in the center; an annular membrane portion 3b formed with a thin wall to facilitate bending and support the valve core portion 3a; and an outer peripheral portion 3c located on the outer periphery of the membrane portion 3b (see reference). Figure 2The valve core 3a has a shape resembling a truncated cone connected to a cylinder, i.e., a hammer shape with a conical upper end. Furthermore, the valve core 3a is positioned so that its bottom surface faces the valve seat 5a. Additionally, an annular rib 31 protruding towards the valve seat 5a is provided on the bottom surface of the valve core 3a. Furthermore, the diaphragm 3b is formed extending radially outward from the outer periphery of the upper end of the valve core 3a, and the outer periphery of the diaphragm 3b has a generally circular shape. Furthermore, at least a portion of the outer peripheral edge 3c is sandwiched between the upper surface of the area surrounding the upper opening of the valve chamber 11 of the main body 5 and the bottom surface of the drive housing 17. In this way, the diaphragm 3, with the valve core 3a supported within the valve chamber 11 via the diaphragm 3b, divides the valve chamber 11 from the drive unit 7.

[0092] It should be noted that as long as the rib 31 of the valve core 3a, which moves back and forth in the direction of the moving axis C due to the deformation of the membrane 3b, abuts against / separates from the valve seat 5a, the connection between the first flow path (specifically the inlet flow path 13) and the second flow path (specifically the outlet flow path 15) can be opened / closed, the shape of the valve seat 5a, the valve core 3a, and the rib 31 is not limited.

[0093] The valve core portion 3a of the diaphragm 3 has an upwardly opening connection hole 37. The connection hole 37 includes a small-diameter hole portion 37a located on the side near the drive portion 7 and a large-diameter hole portion 37b connected to the lower part of the small-diameter hole portion 37a. The top end (lower end) of the valve stem 19 has a locking portion 19a that is larger than the middle portion. The locking portion 19a is pressed through the small-diameter hole portion 37a into the large-diameter hole portion 37b, thereby connecting the diaphragm 3 to the valve stem 19. The diaphragm 3 (specifically the valve core portion 3a) can abut / separate from the valve seat portion 5a via the valve stem 19 as the piston 21 moves up and down.

[0094] like Figure 2 As shown, the diaphragm 3 has: a base 33a, made of non-crosslinked fluoropolymer; and an end portion 33b, integral with respect to the base 33a, having ribs 31 and made of crosslinked PFA. That is, the base 33a, including the membrane portion 3b, is formed of a non-crosslinked fluoropolymer, which is cheaper and has higher bending durability than crosslinked PFA. Furthermore, the end portion 33b, including the ribs 31 (specifically the bottom of the valve core portion 3a), is formed of crosslinked PFA, which has high wear resistance and strength. Moreover, the diaphragm 3 is cut from a composite 45, which is integrally formed from an intermediate 44, which will become the base 33a, made of non-crosslinked fluoropolymer, and a reshaped piece 43 (which will become the end portion 33b) of a cut piece 42 of a crosslinked PFA membrane crosslinked with a tertiary carbon concentration greater than or equal to 0.01 mol% (see reference). Figures 5-7 ).

[0095] The type of fluoropolymer used to form the aforementioned non-crosslinked fluoropolymer is not limited. Polymers (homopolymers or copolymers) using fluorinated polymerizable compounds such as tetrafluoroethylene [F₂C=CF₂], hexafluoropropylene [F₂C=CF₂-CF₃], difluoroethylene [H₂C=CF₂], trifluorochloroethylene [F₂C=CFCl], and perfluoroalkoxyethylene (perfluoromethoxyethylene [F₂C=CF-O-CF₃], perfluoroethoxyethylene [F₂C=CF-O-CF₂-CF₂], etc.) as monomers can be used. Ethylene (unfluorinated ethylene) can be used as the monomer for the copolymer. Specifically, materials such as PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane, tetrafluoroethylene-perfluoroalkoxyethylene copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), ETFE (ethylene-tetrafluoroethylene copolymer), PVDF (polyvinylidene fluoride, difluoroethylene polymer), PCTFE (polychlorotrifluoroethylene), and ECTFE (ethylene-chlorotrifluoroethylene copolymer) can be used. Only one of these materials can be used, or two or more can be used in combination. Among these, non-crosslinked PTFE is preferred as the base 33a, considering its ability to suppress melting caused by heating and maintain shape through gelation, as well as its ability to reduce material costs.

[0096] Furthermore, crosslinking in fluoropolymers refers to the formation of carbon-carbon bonds between the different polymer molecules constituting the fluoropolymer. Therefore, tertiary carbon is typically absent in non-crosslinked PFA, but present in crosslinked PFA. Thus, the presence or absence of tertiary carbon corresponds to the presence or absence of crosslinking within the PFA; the higher the concentration of tertiary carbon, the more crosslinking occurs within the PFA. In this invention, crosslinking is assumed to occur when the tertiary carbon concentration is greater than or equal to 0.01 mol%. There is no upper limit to this tertiary carbon concentration, but it is typically less than or equal to 0.7 mol%. By maintaining the tertiary carbon concentration at less than or equal to 0.7 mol%, the mechanical strength of the crosslinked PFA can be maintained at a high level.

[0097] Through cross-linking PFA 19 F-NMR determination (measuring apparatus: solid) 19 F-NMR (Bruker Biospin AVANCEIII-400 WB, measurement conditions: 376MHz, rotation speed 27kHz), measure the integral values ​​of each peak A to G shown in Table 1 below, and then use the following calculation formula (1) (based on peak C) to calculate the tertiary carbon concentration.

[0098] It should be noted that the presence of tertiary carbon can be determined by the presence of peak C and / or peak G. As mentioned above, the concentration of tertiary carbon is basically calculated using the peak intensity of peak C according to formula (1). However, if peak C is not detected but only peak G is detected, the concentration of tertiary carbon is calculated using the following formula (2). The concentration of tertiary carbon calculated by formula (1) and the concentration of tertiary carbon calculated by formula (2) are usually substantially equivalent values.

[0099] Furthermore, the following calculation formula shows [I] A / 3 ]、[I B / 5 ]、[I C / 6 ]、[I D / 4 ]、[I E / 2 ]、[I F / 1 ] and [I G / 1 The results are shown below.

[0100] [I A / 3 ]: The equivalent F contained in the structure of “A” in Table 1 There are 3, therefore the peak intensity based on "A" is set to "I". A When “A” contains one F, it is relative to the 1 F in “A”. The peak intensity is "I A / 3”, record this value as [I A / 3 ].

[0101] [I B / 5 ]: The equivalent F contained in the structure of “B” in Table 1 There are 5, therefore the peak intensity based on "B" is set to "I". B When “”, relative to the 1 F contained in “B” The peak intensity is "I B / 5”, record this value as [I B / 5 ].

[0102] [I C / 6 ]: The equivalent F contained in the structure of “C” in Table 1 There are 6, therefore the peak intensity based on "C" is set to "I". C When “”, it is relative to the 1 F contained in “C”. The peak intensity is "I C / 6”, record this value as [I C / 6 ].

[0103] [I D / 4 ]: The equivalent F contained in the structure of “D” in Table 1 There are 4, therefore the peak intensity based on "D" is set to "I". D When “”, relative to the 1 F contained in “D”. The peak intensity is "ID / 4”, record this value as [I D / 4 ].

[0104] [I E / 2 ]: The equivalent F contained in the structure of “E” in Table 1 Since there are two, the peak intensity based on "E" is set to "I". E When “”, it is relative to the 1 F contained in “E”. The peak intensity is "I E / 2”, record this value as [I E / 2 ].

[0105] [I F / 1 ]: The equivalent F contained in the structure of “F” in Table 1 Since there is one, the peak intensity based on "F" is set to "I". F When “”, it is relative to the 1 F contained in “F”. The peak intensity is "I F / 1”, record this value as [I F / 1 ].

[0106] [I G / 1 ]: The equivalent F contained in the structure of “G” in Table 1 Since there is one, the peak intensity based on "G" is set to "I". G When “”, relative to the 1 F contained in “G” The peak intensity is "I G / 1”, record this value as [I G / 1 ].

[0107] [Calculation formula (1)] Based on I C / 6 tertiary carbon concentration

[0108] Tertiary carbon concentration (mol%) = [I C / 6 ] / {[I A / 3 ]+[I B / 5 ]+[I D / 4 ]+[I E / 2 ]+[I F / 1 ]+[I G / 1 ]}×100

[0109] [Calculation formula (2)] Based on I G / 1 tertiary carbon concentration

[0110] Tertiary carbon concentration (mol%) = {[I G / 1 ]-[I A / 3 ]} / {[I B / 5 ]+[I C / 6 ]+[I D / 4 ]+[I E / 2 ]+[IF / 1 ]}×100

[0111] [Table 1]

[0112]

[0113] Rib 31 is composed of cross-linked PFA from its tip to its root. With the tertiary carbon concentration at the tip set as M1 (mol%) and at the root set as M2 (mol%), the following conditions are met: M1 > 0.01, M2 > 0.01, and 0.8 ≤ M1 / M2 ≤ 1.2. That is, the tertiary carbon concentration M1 at the tip of rib 31 exceeds 0.01 mol%, and the tertiary carbon concentration M2 at the root also exceeds 0.01 mol%. Furthermore, these M1 / M2 ratios are greater than or equal to 0.8 and less than or equal to 1.2, with M1 and M2 showing close values. Therefore, rib 31 is formed from uniformly cross-linked PFA from its tip to its root. Additionally, the distance between the tip and root of rib 31 is approximately 250 μm to 2000 μm, set to greater than or equal to 250 μm.

[0114] Such ribs 31, which are composed of cross-linked PFA uniformly cross-linked from top to bottom, can be formed arbitrarily, but can be formed from a reshaped piece 43 of a cross-linked PFA film cut into pieces 42, which are cross-linked in such a way that the tertiary carbon concentration is greater than or equal to 0.01 mol% (see reference). Figure 5 ).

[0115] That is, for example, if it is a thin film of non-crosslinked PFA less than 250 μm, radiation can be irradiated on both sides of the film. On the other hand, for example, if it is a thick film of non-crosslinked PFA greater than or equal to 250 μm, radiation is difficult to pass through, resulting in a crosslinked PFA film with different degrees of crosslinking on the surface and back. In addition, the output power of the radiation can be increased to make it pass through the surface and back of the non-crosslinked PFA film, but the result is that the degree of crosslinking on the surface and back is sometimes different due to attenuation during transmission. Furthermore, the use of high-output-power radiation leads to a sharp increase in cost, making it difficult to adopt. Therefore, in order to reliably crosslink and obtain a crosslinked PFA with a high degree of shape freedom at low cost, a thin film of non-crosslinked PFA less than 250 μm is irradiated on both sides of the film to make the film uniformly crosslinked. Then, the cut piece 42 of the film is reshaped to obtain a uniformly crosslinked PFA with a desired shape. Moreover, for example, in fluoropolymers, PTFE is difficult to melt-form regardless of whether it is crosslinked or not. In contrast, PFA can melt and form even after crosslinking, so block-shaped crosslinked PFA can also be obtained from the cut piece 42 of the crosslinked PFA film by reshaping.

[0116] On the other hand, the valve seat portion 5a of the main body 5 is provided with an abutment portion 39, which abuts against the rib 31 of the valve core portion 3a of the diaphragm 3. The abutment portion 39 is composed of an annular facet. However, the shape of the abutment portion 39 is not limited as long as it can abut against the rib 31. In addition, as Figure 3 As shown, the main body 5 has: a base 35a, made of non-crosslinked fluoropolymer; and an end portion 35b, integral with respect to the base 35a, having an abutment portion 39 and made of crosslinked fluoropolymer. That is, the base 35a (specifically, the portion of the main body 5 with a larger volume than the end portion 35b) is formed of non-crosslinked PTFE, which is less expensive than crosslinked fluoropolymer. Furthermore, the end portion 35b, including the abutment portion 39, is formed of a crosslinked fluoropolymer with high wear resistance and strength.

[0117] It should be noted that the non-crosslinked fluororesin constituting the base 35a can be any of the aforementioned non-crosslinked fluororesins. Furthermore, the crosslinked fluororesin constituting the end 35b can be any of the aforementioned crosslinked fluororesins, with crosslinked PFA being particularly preferred.

[0118] Next, the manufacturing method of the diaphragm valve 1A configured as described above will be explained.

[0119] First, an intermediate part 44 having a cylindrical cavity 44a is made of a non-crosslinked fluoropolymer. PTFE can be used as the non-crosslinked fluoropolymer.

[0120] In the first embodiment, the following is made: Figure 6 The illustrated intermediate member 44 is a cup-shaped part with a recess at its upper end that functions as a cavity 44a. The intermediate member 44 can be formed by any method, for example, by machining the recess into the upper end of a rod or plate formed by compression molding from non-crosslinked fluoropolymer using a free-baking method, hot molding method, or similar method. Similarly, it can also be formed by compression molding from non-crosslinked fluoropolymer using a free-baking method, hot molding method, or similar method, into a cup-shaped rod or plate with a recess at its upper end.

[0121] Furthermore, the intermediate part 44 does not need to be integrally formed; for example, it can be manufactured by combining a cylindrical tubular body with a solid rod-shaped body or plate-shaped body (including sheet-like objects) disposed adjacent to its lower part. In this case, the tubular body and the rod-shaped body or plate-shaped body can be joined by screwing or interlocking. Moreover, if the tubular body and the rod-shaped body or plate-shaped body (including sheet-like objects) are integrally formed, they can be joined by welding after being manufactured separately. Welding can be performed, for example, by laser welding, hot plate welding, hot air welding, heating block welding, diffusion bonding, firing, etc. When the intermediate part 44 is made of a rod-shaped body of non-crosslinked fluoropolymer resin, the rod-shaped body of non-crosslinked fluoropolymer resin can also be manufactured by extrusion molding.

[0122] On the other hand, products made from cross-linked PFA, such as Figure 6 The reshaped part 43 shown has a shape and size that can be accommodated within the cavity 44a (recess) of the intermediate part 44. The reshaped part 43 can be reshaped in a location other than the cavity 44a or inside the cavity 44a.

[0123] When remolding occurs outside of cavity 44a, a rod-shaped body can be remolded from cross-linked PFA in the same manner as the aforementioned intermediate piece 44, with its outer peripheral shape complementary to the inner peripheral surface of the cylindrical cavity 44a. In this case, as the raw material for cross-linked PFA, a cut sheet 42 of a cross-linked PFA film cross-linked to a concentration of tertiary carbon greater than or equal to 0.01 mol% can be used. That is, for example, such as... Figure 5 As shown in (a), a cross-linked PFA film 41 can be formed by irradiating a film composed of non-cross-linked PFA (non-cross-linked PFA film) with radiation. That is, by irradiating a non-cross-linked PFA film formed in the form of a thin film with radiation, a cross-linked PFA film formed by uniform cross-linking throughout its surface and back can be obtained. More specifically, by irradiating with radiation at an accelerating voltage at a temperature above the melting point of the non-cross-linked PFA and at an accelerating voltage at which the absorbed dose on the back side of the irradiated surface is greater than or equal to 20% (preferably greater than or equal to 60%) of the absorbed dose on the surface relative to the thickness of the non-cross-linked PFA film to be irradiated, a cross-linked PFA film with a tertiary carbon concentration of greater than or equal to 0.01 mol% throughout the surface and back of the film can be obtained.

[0124] Then, as Figure 5 As shown in (b), a cross-linked PFA film uniformly cross-linked throughout its surface and back is cut to obtain cut pieces 42, thereby obtaining cross-linked PFA materials with higher shape freedom. Further, as... Figure 5As shown in (c), a cut piece 42 of a cross-linked PFA film is placed in the cavity of a mold 46 having a predetermined shape, heated and melted, and then solidified to obtain a reshaped article 43. This reshaped article 43 can be housed in the cavity 44a after being shaped by cutting or the like in a manner that allows it to be accommodated in the cavity 44a of the intermediate part 44. Furthermore, from the viewpoint of being able to heat and melt the reshaped article 43, as long as the reshaped article 43 does not overflow from the cavity 44a during heating and melting, the height of the reshaped article 43 can be approximately equal to or shorter than the depth of the cavity 44a. The reshaped article 43 can also be directly manufactured from cross-linked PFA by extrusion molding, injection molding using a mold, or the like.

[0125] On the other hand, if the reshaped material 43 is reshaped inside cavity 44a, such as Figure 11 As shown, the cut piece 42 of the aforementioned cross-linked PFA film is accommodated in the cavity 44a (cut piece accommodation process), and heated and melted in the cavity 44a, thereby obtaining a reshaped article 43 made of cross-linked PFA with a shape complementary to the inner circumferential surface of the cavity 44a.

[0126] In this case, only the cut piece 42 of the cross-linked PFA film contained in the cavity 44a can be heated and melted, but heating can also be performed in a manner that includes the cavity 44a. That is, for example, the entire intermediate piece 44 can be heated. This method is preferably used when the intermediate piece 44 is made of non-cross-linked PTFE. Non-cross-linked PTFE will gel even at the temperature at which cross-linked PFA can be heated and melted without melting. Therefore, the approximate shape of the intermediate piece 44 and the cavity 44a can be maintained. Then, after the cut piece 42 of the cross-linked PFA film is heated and melted, it is reshaped into a shape corresponding to the cavity 44a. Then, when it is cooled and solidified, the cavity 44a is also cooled and solidified at the same time. At this time, the two (the intermediate piece 44 and the reshaped piece 43) are integrated to obtain their composite piece 45 (firing process).

[0127] If the reshaped part 43 is reshaped inside the cavity 44a in this way, the production of the reshaped part 43 and the integration of the resulting reshaped part 43 with the intermediate part 44 can be achieved through a single heating, melting, and cooling solidification process, thus achieving excellent manufacturing efficiency. Furthermore, a mold for obtaining the reshaped part 43 is not required, allowing for low-cost manufacturing of the diaphragm valve. Moreover, by heating the intermediate part 44 as a whole while obtaining the reshaped part 43 inside the cavity 44a, strain and residual stress can be suppressed, resulting in excellent bonding strength between the two. This effect is even more pronounced by heating under non-pressurized conditions (without special pressurization). Furthermore, since the reshaped part 43 is reshaped inside the cavity 44a, the entire contact surface of both the cavity 44a and the reshaped part 43 can be joined, thus achieving a more robust bond between the intermediate part 44 and the reshaped part 43 compared to composite parts with selective bonding areas, such as laser welding. Furthermore, even when external forces are applied to the composite 45, gaps between the two can be prevented.

[0128] As described above, a rod-shaped composite 45 obtained by reshaping the reshaped material 43 inside the cavity 44a is used as a test piece. The intermediate part 44 and the reshaped material 43 are separated and a tensile test is performed. As a result, it is confirmed that the joint between the intermediate part 44 and the reshaped material 43 does not break, but the breakage occurs at the part other than the joint.

[0129] It should be noted that when obtaining cross-linked PFA, it is possible to use non-cross-linked PFA film instead of non-cross-linked PFA film, for example, by selecting non-cross-linked PFA powder as the starting material. However, when obtaining cross-linked PFA powder from non-cross-linked PFA powder, the cross-linked PFA powder needs to be reshaped, but there is a problem that the melt tends to contain gas during heating and melting. That is, compared with uncross-linked PFA, the melt viscosity of cross-linked PFA is higher, and the higher the degree of cross-linking, the higher the melt viscosity. Therefore, when prioritizing wear resistance, degassing requires effort and cost. Therefore, from the viewpoint of excellent degassing during heating and melting, it is preferable to use cut sheets of cross-linked PFA film. In addition, cross-linked PFA film can also be pulverized into powder or microparticles, but it is low-cost to make cut sheets. Moreover, from the viewpoint of more effectively maintaining the mechanical strength obtained through cross-linking, it is also preferable to use it as a cut sheet.

[0130] Furthermore, as described above, when the intermediate part 44 is heated as a whole to melt the cut piece 42 housed in the cavity 44a to obtain the reshaped part 43 (firing process), the integration process can be performed simultaneously with its cooling and solidification. However, equivalent effects can also be obtained by the method described below. That is, for example, integration can be performed using the following injection molding process: molten material of the cross-linked PFA film cut piece 42 is injected into the cavity 44a of the intermediate part 44, the reshaped part 43 is obtained in the cavity 44a, and the intermediate part 44 and the reshaped part 43 are integrated. Alternatively, after accommodating the cross-linked PFA film cut piece 42 in the cavity 44a of the intermediate part 44 (cut piece accommodation process), the cut piece 42 can be compressed in the cavity 44a to obtain the reshaped part 43, and the intermediate part 44 and the reshaped part 43 can be integrated (compression molding process). Heating can be performed simultaneously during this compression. Heating can be set to the required temperature, for example, a temperature below the melting point of cross-linked PFA or a temperature above the melting point of cross-linked PFA.

[0131] On the other hand, if a remolded part 43 is obtained separately, an integration process is performed to obtain a composite part 45 formed by integrating the intermediate part 44 with the remolded part 43 housed within its cavity 44a (recess). Integration can be performed by any method, for example, by simultaneously heating both to a temperature higher than the melting point of the non-crosslinked fluoropolymer constituting the intermediate part 44 and the melting point of the crosslinked PFA constituting the remolded part 43. That is, only at least one of the intermediate part 44 and the remolded part 43 melts at least on its surface, thereby enabling the two to be joined.

[0132] Furthermore, the joining of the intermediate part 44 and the reshaped part 43 can also be achieved by welding. That is, it can be achieved by a welding process that obtains a composite part formed by welding the intermediate part 44 and the reshaped part 43 together. This welding can be performed, for example, by laser welding, hot plate welding, hot air welding, heating block welding, diffusion bonding, etc. It should be noted that these methods can be described as methods of welding the intermediate part 44 and the reshaped part 43 together by melting at least a portion of the contact area between them.

[0133] Figure 7 (a) ~ Figure 7 (b) illustrates a method for fabricating the diaphragm 3 from the composite 45. (See diagram 45 for details.) Figure 7 As shown by the dashed line in (a), the composite part 45 is machined to produce a product like... Figure 7 Diaphragm 3 is shown in (b). Figure 7 The diaphragm 3 shown in (b) is... Figure 1The diaphragm used in the diaphragm valve 1A shown. In the diaphragm 3, the membrane portion 3b having a base portion 33a in the central portion is made of an intermediate portion 44 formed of a non-crosslinked fluoropolymer in the composite 45. It should be noted that, from the viewpoint of high bending durability, the non-crosslinked fluoropolymer constituting the intermediate portion 44 is formed of PTFE.

[0134] Furthermore, from the viewpoint of low dust generation, the end portion 33b of the diaphragm 3 is formed of cross-linked PFA. In addition, in the composite 45, the intermediate portion 44 and the reshaped part 43 are integrally joined by firing (integral melt molding). Therefore, the entire surface of the boundary (joining surface) between the base portion 33a and the end portion 33b of the diaphragm 3 is integrally joined. Therefore, even if the end portion 33b is impacted and deformed when it abuts against the valve seat portion 5a during valve closure, no gap will be generated at the boundary surface between the base portion 33a and the end portion 33b, preventing liquid intrusion into the valve chamber 11 and thus preventing a decrease in strength. Furthermore, both the intermediate portion 44 and the reshaped part 43 are heated and then cooled as a whole, thus suppressing the generation of thermal strain and the reduction in strength caused by thermal strain.

[0135] It should be noted that the range of components made from different fluororesins can be altered by cutting them out from appropriate locations. That is, in Figure 7 (a) ~ Figure 7 In (b), only the vicinity of the contact surface that abuts against the valve seat portion 5a is made of cross-linked PFA with low dust generation, but for example... Figure 8 (a) ~ Figure 8 As shown in (b), by changing the cutting position, the end portion 33b made of cross-linked PFA can be made larger, while the base portion 33a made of non-cross-linked fluoropolymer can be made smaller. On the other hand, as Figure 10 (a) ~ Figure 10 As shown in (b), it can be configured such that only rib 31 is made of cross-linked PFA, while the rest is made of non-cross-linked fluoropolymer. Furthermore, as... Figure 10 (a) ~ Figure 10 As shown in (b), when only rib 31 is made of cross-linked PFA, the size of the reshaped part 43 within the composite 45 can be kept small. Therefore, the amount of cross-linked PFA used, which is more expensive than non-cross-linked fluoropolymers, can be reduced, and a membrane with excellent performance can be obtained.

[0136] Next, the effects of the diaphragm valve 1A constructed as described above will be explained. For example... Figure 1As shown, in the normal state where no working fluid is supplied to the drive unit 7 from the working fluid supply port 27, the piston 21 of the drive unit 7 is pressed down by the helical spring 22. As a result, the valve core 3a moves towards the valve seat 5a via the valve stem 19, and the rib 31 of the valve core 3a presses against the valve seat 5a, thus closing the diaphragm valve 1A (see reference). Figure 4 (a) Along with this, the diaphragm portion 3b supporting the valve core portion 3a also deforms away from the drive portion 7. If working fluid is supplied from this state to the working fluid supply port 27 of the drive portion 7, the fluid pressure of the working fluid flowing into the lower space S2 of the cylinder acts upward on the piston body 21a, and the piston 21 is pushed upward against the force applied by the coil spring 22. At this time, the air in the upper space S1 is released to the outside through the vent port 26. As a result, the valve core portion 3a moves away from the valve seat portion 5a via the valve stem 19, and the diaphragm valve 1A becomes open (see reference). Figure 4 (b) . Along with this, the diaphragm 3b also deforms toward the drive 7. When the supply of working fluid to the working fluid supply port 27 is stopped, the piston 21 is pressed down again by the helical spring 22, and the rib 31 of the valve core 3a is pressed into the valve seat 5a, returning to the closed valve state.

[0137] In summary, according to the diaphragm valve 1A of this embodiment, a rib 31 protruding toward the valve seat 5a is provided in the valve core 3a. The rib 31 is composed of cross-linked PFA from its tip to its root. When the tertiary carbon concentration at the tip is set to M1 (mol%) and the tertiary carbon concentration at the root is set to M2 (mol%), M1>0.01, M2>0.01 and 0.8≤M1 / M2≤1.2 are satisfied. As a result, the rib 31 is formed of uniformly cross-linked PFA from its tip to its root, thus improving the wear resistance and strength of the rib 31. Therefore, it is possible to suppress the deformation of the rib 31 when it comes into contact with the valve seat 5a during valve closure, thus reducing the amount of particles generated.

[0138] <Example 2>

[0139] Next, the diaphragm valve 1B of Embodiment 2 will be described, but the same reference numerals will be used for components that are substantially the same as those of the diaphragm valve 1A of Embodiment 1, and detailed descriptions will be omitted. The differences between the two will be described in detail. The main difference between the two is that in Embodiment 1, a rib 31 is provided in the valve core portion 3a of the diaphragm 3, while in Embodiment 2, a rib 31 is provided in the valve seat portion 5a of the body 5.

[0140] like Figure 12As shown, the diaphragm valve 1B of this embodiment includes: a diaphragm 3 having a valve core portion 3a and a membrane portion 3b extending outward from the valve core portion 3a and deformable in the direction of the moving axis C; and a body 5 having a valve seat portion 5a, which is used to abut and separate the valve core portion 3a, which reciprocates in the direction of the moving axis C due to the deformation of the membrane portion 3b (see reference). Figure 15 Furthermore, the diaphragm valve 1B includes a drive unit 7 for driving the diaphragm 3.

[0141] In the main body 5, an annular valve seat portion 5a is formed around the opening from the first flow path to the valve chamber 11 for the diaphragm 3 (specifically, the valve core portion 3a) to abut / separate from. Figure 14 The valve seat portion 5a is provided with an annular rib 31 protruding toward the valve core portion 3a.

[0142] It should be noted that as long as the valve core 3a, which moves back and forth in the direction of the moving axis C due to the deformation of the membrane 3b, abuts or separates from the rib 31 of the valve seat 5a, the connection between the first flow path (specifically the inlet flow path 13) and the second flow path (specifically the outlet flow path 15) can be opened / closed, the shape of the valve seat 5a, the valve core 3a and the rib 31 are not limited.

[0143] like Figure 14 As shown, the main body 5 has: a base 35a, made of non-crosslinked fluoropolymer; and an end portion 35b, integral with respect to the base 35a, having ribs 31 and made of crosslinked PFA. That is, the base 35a (specifically, the portion of the main body 5 with a larger volume than the end portion 35b) is formed of a non-crosslinked fluoropolymer, which is cheaper than crosslinked PFA. Furthermore, the end portion 35b, including the ribs 31, is formed of crosslinked PFA, which has high wear resistance and strength. Moreover, the main body 5 is cut from a composite 45, which is an integral part of a non-crosslinked fluoropolymer intermediate 44 that will become the base 35a, and a reshaped piece 43 (i.e., a reshaped piece 43 that will become the end portion 35b) of a cut piece 42 of a crosslinked PFA film crosslinked with a tertiary carbon concentration greater than or equal to 0.01 mol% (see reference). Figures 16-18 ).

[0144] Rib 31 is composed of cross-linked PFA from its tip to its root. With the tertiary carbon concentration at the tip set as M1 (mol%) and at the root set as M2 (mol%), the following conditions are met: M1 > 0.01, M2 > 0.01, and 0.8 ≤ M1 / M2 ≤ 1.2. Therefore, rib 31, formed from uniformly cross-linked PFA from its tip to its root, exhibits high wear resistance and strength.

[0145] The type of fluoropolymer used to form the aforementioned non-crosslinked fluoropolymer is not limited. Similar to Example 1, polymers (homopolymers or copolymers) using tetrafluoroethylene, hexafluoropropylene, difluoroethylene, trifluorochloroethylene, perfluoroalkoxyethylene, etc., as monomers can be used. Specifically, polymers (homopolymers or copolymers) utilizing fluorinated polymerizable monomers can be used, specifically PTFE, PFA, FEP, ETFE, PVDF, PCTFE, ECTFE, etc. Only one of these can be used, or two or more can be used in combination. Among these, non-crosslinked PTFE is preferred as the base 35a from the viewpoints of suppressing melting caused by heating and maintaining shape through gelation, and from the viewpoint of reducing material costs.

[0146] On the other hand, the end 35b is formed of cross-linked PFA with high wear resistance and strength, but as in Example 1, the tertiary carbon concentration of the cross-linked PFA is preferably greater than or equal to 0.01 mol%, with no upper limit, but usually less than or equal to 0.7 mol%. In addition, the determination of the tertiary carbon concentration is also the same as in Example 1.

[0147] When rib 31 is provided on the main body 5, similarly to the case in Example 1, rib 31 is composed of cross-linked PFA from its tip to its root. With the tertiary carbon concentration at the tip set as M1 (mol%) and the tertiary carbon concentration at the root set as M2 (mol%), the following conditions are met: M1 > 0.01, M2 > 0.01, and 0.8 ≤ M1 / M2 ≤ 1.2. That is, the tertiary carbon concentration M1 at the tip of rib 31 exceeds 0.01 mol%, and the tertiary carbon concentration M2 at its root also exceeds 0.01 mol%. Furthermore, the ratio of M1 to M2 (M1 / M2) is greater than or equal to 0.8 and less than or equal to 1.2, with M1 and M2 showing close values. Therefore, rib 31 is formed from uniformly cross-linked PFA from its tip to its root. In addition, the distance between the tip and root of rib 31 is approximately 250 μm to 2000 μm, set to be greater than or equal to 250 μm.

[0148] Such ribs 31, formed from uniformly cross-linked PFA from top to bottom, can be formed arbitrarily, but similarly to the case of Example 1, they can be formed from the reshaped part 43 of the cut piece 42 of the cross-linked PFA film (see Figure 1). Figure 16 In this case, the effect is the same as in Example 1. That is, as... Figure 16 As shown in (a), a cross-linked PFA membrane 41 is formed by irradiating a membrane composed of non-cross-linked PFA (non-cross-linked PFA membrane) with radiation, as shown in (a). Figure 16 As shown in (b), the cross-linked PFA film, which is uniformly cross-linked throughout its surface and back, is cut to obtain cut pieces 42, and then as shown in (b). Figure 16As shown in (c), a cut piece 42 of a cross-linked PFA film is placed in the cavity of a mold 46 having a specified shape, heated and melted, and then solidified to obtain a reshaped article 43.

[0149] A contact portion 39 is provided on the bottom surface of the valve core portion 3a of the diaphragm 3, which abuts against the rib 31 of the valve seat portion 5a of the main body 5. The contact portion 39 is composed of annular facets. However, the shape of the contact portion 39 is not limited as long as it can be abutted against by the rib 31. In addition, such as Figure 13 As shown, the diaphragm 3 has: a base 33a, made of non-crosslinked PTFE; and an end portion 33b, integral with respect to the base 33a, having an abutment portion 39, and made of crosslinked fluoropolymers such as PTFE and PFA. That is, the base 33a, including the membrane portion 3b, is formed of non-crosslinked PTFE, which is cheaper and has higher bending durability than crosslinked fluoropolymers. Furthermore, the end portion 33b, including the abutment portion 39 (specifically, the bottom of the valve core portion 3a), is formed of a crosslinked fluoropolymer with high wear resistance and strength.

[0150] Next, the manufacturing method of the diaphragm valve 1B configured as described above will be explained.

[0151] First, such as Figure 17 (a) ~ Figure 17 As shown in (b), similarly to the case of Example 1, the intermediate piece 44 having a cylindrical cavity 44a is made of non-crosslinked fluororesin. On the other hand, as... Figure 16 (a) ~ Figure 16 As shown in (c), a reshaped part 43 that can be accommodated in the cavity 44a (recess) is made using a cut piece 42 of a cross-linked PFA film cross-linked in such a way that the tertiary carbon concentration is greater than or equal to 0.01 mol%. Then, the reshaped part 43 is accommodated in the cavity 44a of the intermediate part 44, and the two are joined together by an appropriate method, as in the case of Example 1, thereby obtaining a composite part in which the intermediate part 44 and the reshaped part 43 are integrally formed.

[0152] On the other hand, similar to the case in Example 1, when the reshaped material 43 is reshaped inside the cavity 44a, such as... Figure 23 As shown, a cut piece 42 of a cross-linked PFA film is accommodated in a cavity 44a (cut piece accommodation process), and heated and melted in the cavity 44a, thereby obtaining a reshaped article 43 made of cross-linked PFA with a shape complementary to the inner circumferential surface of the cavity 44a.

[0153] In this case, only the cut piece 42 of the cross-linked PFA film contained in the cavity 44a can be heated and melted, but heating can also be performed in a manner that includes the cavity 44a. That is, for example, the entire intermediate piece 44 can be heated. This method is preferably used when the intermediate piece 44 is made of non-cross-linked PTFE. Non-cross-linked PTFE will gel even at the temperature at which cross-linked PFA can be heated and melted without melting. Therefore, the approximate shape of the intermediate piece 44 and the cavity 44a can be maintained. Then, after the cut piece 42 of the cross-linked PFA film is heated and melted, it is reshaped into a shape corresponding to the cavity 44a. Then, when it is cooled and solidified, the cavity 44a is also cooled and solidified at the same time. At this time, the two (the intermediate piece 44 and the reshaped piece 43) are integrated to obtain their composite piece 45 (firing process).

[0154] If the reshaped part 43 is reshaped inside the cavity 44a in this way, the production of the reshaped part 43 and the integration of the resulting reshaped part 43 with the intermediate part 44 can be achieved through a single heating, melting, and cooling solidification process, thus achieving excellent manufacturing efficiency. Furthermore, a mold for obtaining the reshaped part 43 is not required, allowing for low-cost manufacturing of the diaphragm valve. Moreover, by heating the intermediate part 44 as a whole while obtaining the reshaped part 43 inside the cavity 44a, strain and residual stress can be suppressed, resulting in excellent bonding strength between the two. This effect is even more pronounced by heating under non-pressurized conditions (without special pressurization). Furthermore, since the reshaped part 43 is reshaped inside the cavity 44a, the entire contact surface of both the cavity 44a and the reshaped part 43 can be joined, thus achieving a more robust bond between the intermediate part 44 and the reshaped part 43 compared to composites with selective joining points, such as laser welding. Furthermore, even when external forces are applied to the composite 45, gaps between the two can be prevented.

[0155] As described above, a rod-shaped composite 45 obtained by reshaping the reshaped material 43 inside the cavity 44a is used as a test piece. The intermediate part 44 and the reshaped material 43 are separated and a tensile test is performed. As a result, it is confirmed that the joint between the intermediate part 44 and the reshaped material 43 does not break, but the breakage occurs at the part other than the joint.

[0156] Figure 18 (a) ~ Figure 18 (b) and Figure 19 (a) ~ Figure 19 (b) shows a method for making the main body 5 from the composite 45.

[0157] like Figure 18 As shown by the dashed line in (a), the composite part 45 is machined to produce a product like... Figure 18 The main body 5 is shown in (b). Figure 18 The main body 5 shown in (b) is in Figure 12 The body used in the diaphragm valve 1B shown is as follows. In the body 5, the end 35b with ribs 31 is formed in the composite 45 by a remolded part 43, i.e., formed from cross-linked PFA with low dust generation. Furthermore, the base 35a of the body 5, which forms the inlet 12 and outlet 14, is formed in the composite 45 by an intermediate part 44, i.e., formed from a non-cross-linked fluoropolymer, which is less expensive than cross-linked PFA. The inlet flow path 13 and outlet flow path 15 are cut out from the intermediate part 44 in such a way that they extend from the inlet 12 and outlet 14 to the valve chamber 11. On the other hand, the ribs 31 are cut out from the end 35b. Therefore, even when the valve is open / closed, the abutment portion 39 abuts against the valve seat portion 5a, the generation of particles can be suppressed, reducing the contamination of the liquid in the valve chamber 11 by the generated particles.

[0158] according to Figure 18 (a) ~ Figure 18 Method (b) allows for the cutting of the flow path 13 from the inlet 12, the valve chamber 11, and the flow path 15 from the outlet 14 from the base 35a. On the other hand, it allows for the cutting of only the valve seat 5a from the end 35b. Therefore, compared with... Figure 19 (a) ~ Figure 19 Compared to the cutting method shown in (b), particle generation can be suppressed, and the main body 5 can be manufactured at a low cost.

[0159] In addition, such as Figure 20 (a) ~ Figure 20 As shown in (b), after forming the reshaped part 43 in the cavity 44a of the intermediate part 44, other intermediate parts 48 can be further formed using other non-crosslinked fluoropolymers. Even so, compared with the method of... Figure 19 (a) ~ Figure 19 Compared to the cutting method shown in (b), particle generation can be suppressed, and the main body 5 can be manufactured at a low cost.

[0160] Moreover, such as Figure 22 (a) ~ Figure 22 As shown in (b), it can be configured such that only rib 31 is made of cross-linked PFA, while the rest is made of non-cross-linked fluoropolymer. Furthermore, as... Figure 22 (a) ~ Figure 22 As shown in (b), when only rib 31 is made of cross-linked PFA, the size of the reshaped part 43 within the composite 45 can be kept particularly small. Therefore, the amount of cross-linked PFA used, which is more expensive than non-cross-linked fluoropolymers, can be reduced, and a membrane with excellent performance can be obtained.

[0161] Moreover, such as Figure 21 (a) ~ Figure 21 As shown in (b), cavities 44a can be provided in the intermediate part 44 at three locations corresponding to the inlet 12, the valve seat portion 5a, and the outlet 14, respectively. Within each of these three cavities 44a, a remolded part 43 and other remolded parts 49 made of cross-linked PFA are formed. Furthermore, the valve seat portion 5a can be cut from the remolded part 43, and the connector portion of the inlet 12 and the connector portion of the outlet 14 can be cut from the other remolded parts 49, respectively. In this case, dust (particle generation) accompanying the contact / separation of the contact portion 39 and the valve seat portion 5a can be suppressed, as can dust (particle generation) from the connector portion of the pipe connecting the inlet 12 and the outlet 14. On the other hand, such a low-dust-generating body 5 can be manufactured at low cost.

[0162] Next, the effects of the diaphragm valve 1B constructed as described above will be explained. For example... Figure 12 As shown, in the normal state where no working fluid is supplied to the drive unit 7 from the working fluid supply port 27, the piston 21 of the drive unit 7 is pressed down by the helical spring 22. As a result, the valve core 3a moves towards the valve seat 5a via the valve stem 19 and presses against the rib 31 of the valve seat 5a, and the diaphragm valve 1B is in the closed state (see reference). Figure 15 (a) Along with this, the diaphragm 3b supporting the valve core 3a also deforms away from the drive unit 7. If working fluid is supplied from this state to the working fluid supply port 27 of the drive unit 7, the fluid pressure of the working fluid flowing into the lower space S2 of the cylinder acts upward on the piston body 21a, and the piston 21 is pushed upward against the force applied by the coil spring 22. At this time, the air in the upper space S1 is released to the outside through the vent 26. As a result, the valve core 3a moves away from the valve seat 5a via the valve stem 19, and the diaphragm valve 1B becomes open (see reference). Figure 15 (b) . Along with this, the diaphragm 3b also deforms toward the drive 7. When the supply of working fluid to the working fluid supply port 27 is stopped, the piston 21 is pressed down again by the helical spring 22, and the valve core 3a presses against the rib 31 of the valve seat 5a, returning to the closed valve state.

[0163] In summary, according to the diaphragm valve 1B of this embodiment, a rib 31 protruding toward the valve core 3a is provided in the valve seat portion 5a. The rib 31 is composed of cross-linked PFA from its tip to its root. When the tertiary carbon concentration at the tip is set to M1 (mol%) and the tertiary carbon concentration at the root is set to M2 (mol%), M1>0.01, M2>0.01 and 0.8≤M1 / M2≤1.2 are satisfied. As a result, the rib 31 is formed of uniformly cross-linked PFA from its tip to its root, thus improving the wear resistance and strength of the rib 31. Therefore, it is possible to suppress the deformation of the rib 31 and the friction between the rib 31 and the valve core 3a when the valve is closed, thereby reducing the amount of particles generated.

[0164] Industrial availability

[0165] This invention is widely used as a diaphragm valve having a diaphragm for fluid control and a method for manufacturing the same.

[0166] Explanation of reference numerals in the attached figures

[0167] 1A, 1B: Diaphragm valves;

[0168] 3: Diaphragm;

[0169] 3a: Valve core; 3b: Diaphragm; 3c: Outer periphery;

[0170] 5: Main body; 5a: Valve seat;

[0171] 7: Drive unit;

[0172] 11: Valve chamber;

[0173] 12: Inlet; 13: Inlet flow path; 14: Outflow port; 15: Outlet flow path;

[0174] 17: Drive unit housing;

[0175] 18: Cover component;

[0176] 19: Valve stem; 19a: Locking part;

[0177] 21: Piston; 21a: Piston body; 21b: Guide shaft;

[0178] 26: Vent; 27: Working fluid supply port;

[0179] 31: Rib;

[0180] 33a: base; 33b: end; 35a: base; 35b: end;

[0181] 37: Connecting hole; 37a: Small diameter hole section; 37b: Large diameter hole section;

[0182] 39: Butt part;

[0183] 41: Cross-linked PFA membrane; 42: Cut pieces of cross-linked PFA membrane;

[0184] 43: Reshaped product;

[0185] 44: Middleware; 44a: Cavity;

[0186] 45: Composite parts;

[0187] 46: Mold;

[0188] 48: Other intermediate parts; 49: Other reshaped parts;

[0189] C: Moving axis;

[0190] S1: Upper space; S2: Lower space.

Claims

1. A diaphragm valve comprising: a diaphragm having a valve core portion and a membrane portion extending outwardly from the valve core portion and deformable in a direction of a movement axis; and a body having a valve seat portion for contacting and separating from the valve core portion, which reciprocates in the direction of the movement axis due to deformation of the membrane portion, wherein the diaphragm valve is characterized in that... A rib protruding towards the other is provided on either the valve core or the valve seat. The ribs, from their tips to their roots, are composed of cross-linked perfluoroalkoxyalkanes (PFAs). When the tertiary carbon concentration at the tip is set to M1 and the tertiary carbon concentration at the root is set to M2, the following conditions must be met: M1 ≥ 0.01, M2 ≥ 0.01, and 0.8 ≤ M1 / M2 ≤ 1.

2. The unit of M1 is mol%, and the unit of M2 is mole.

2. The diaphragm valve according to claim 1, wherein, The component that is either the diaphragm or the body and has the rib has: The base is composed of non-crosslinked fluoropolymer; and The end portion is integrated relative to the base portion, has the rib, and is composed of the cross-linked PFA.

3. The diaphragm valve according to claim 1, wherein, The distance between the top end and the root of the rib is greater than or equal to 250 μm.

4. The diaphragm valve according to claim 1, wherein, The valve core or the valve seat has a contact portion that abuts against the rib provided on the component of said one. The contact portion is made of cross-linked fluoropolymer.

5. The diaphragm valve according to claim 1, wherein, The rib is composed of a reshaped piece of a cross-linked PFA film, which is cross-linked in such a manner that the concentration of tertiary carbon is greater than or equal to 0.01 mol%.

6. The diaphragm valve according to claim 2, wherein, One of the components is cut from a composite, which is an integral part of a cut piece of a cross-linked PFA film that will become the base, consisting of an intermediate made of non-crosslinked fluoropolymer resin and a crosslinked PFA film with a tertiary carbon concentration of ≥0.01 mol%.

7. A method for manufacturing a diaphragm valve, wherein the method for manufacturing the diaphragm valve is the method for manufacturing the diaphragm valve according to any one of claims 1 to 6, characterized in that, have: The cutting process yields a cut sheet of a cross-linked PFA film formed by cross-linking in a manner that ensures a tertiary carbon concentration of ≥0.01 mol%. The reshaping process reshapes the cut piece to obtain a reshaped object; and The forming process involves obtaining the rib from the reshaped material.

8. The method for manufacturing a diaphragm valve according to claim 7, wherein, The method for manufacturing the diaphragm valve includes: an integrated process to obtain a composite material formed by integrating an intermediate component made of non-crosslinked fluororesin and the remolded material.

9. The method for manufacturing a diaphragm valve according to claim 8, wherein, The integrated process includes: a cut piece receiving process, in which the cut piece is received in a cavity provided in the intermediate component; and In the firing process, the cut piece is melted inside the cavity to obtain the reshaped article, and the intermediate part is integrated with the reshaped article.

10. The method for manufacturing a diaphragm valve according to claim 8, wherein, The integration process includes: an injection molding process, in which molten material of the cut piece is injected into a cavity of the intermediate part to obtain the reshaped part within the cavity, and the intermediate part and the reshaped part are integrated.

11. The method for manufacturing a diaphragm valve according to claim 8, wherein, The integrated process includes: a cut piece receiving process, in which the cut piece is received in a cavity provided in the intermediate component; and In the compression molding process, the cut piece is compressed within the cavity to obtain the reshaped article, and the intermediate part is integrated with the reshaped article.

12. The method for manufacturing a diaphragm valve according to claim 7, wherein, The method for manufacturing the diaphragm valve includes: a welding process to obtain a composite material formed by welding an intermediate component made of non-crosslinked fluororesin to the pre-obtained remolded material.

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