Diaphragm valve and manufacturing method therefor

Abstract

To provide a diaphragm valve that inhibits generation of particles, and a manufacturing method.SOLUTION: A diaphragm valve 1A includes: a diaphragm 3 including a valve body part 3a and a membrane part 3b that extends outward from the valve body part and can deform in a movement axis C direction; and a body 5 including a valve seat part 5a which the valve body part, moving reciprocally in the movement axis direction, comes into contact with and separates from, where one of the valve body part and the valve seat part is provided with a rib 31 protruding toward the other, the rib including a cross-linked PFA from a tip to a base thereof, and a tertiary carbon concentration M1 (mol%) in the tip and a tertiary carbon concentration M2 (mol%) in the base satisfy M1≥0.01, M2≥0.01, and 0.8≤M1 / M2≤1.2. A manufacturing method includes: a step of obtaining a cut piece of a crosslinked PFA film crosslinked such that the tertiary carbon concentration is 0.01 mol% or more; a step of reshaping the cut piece to obtain a reshaped product; and a step of obtaining a rib from the reshaped product.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a diaphragm valve and a manufacturing method thereof, and more particularly to a diaphragm valve equipped with a diaphragm used for fluid control and a manufacturing method thereof. [Background technology]

[0002] Diaphragm valves can be used to control various fluids in various situations, for example, to control the flow and flow rate of chemicals used in semiconductor manufacturing. In this case, the diaphragm valve includes a body and a diaphragm formed from fluororesin such as polytetrafluoroethylene (PTFE) or perfluoroalkoxyalkane (PFA) because of its excellent chemical resistance and bending durability. The body includes a valve chamber connected to a plurality of flow paths, and the diaphragm is made reciprocable in the direction of the movement axis within the valve chamber. As a result, when the diaphragm is reciprocated, a valve body portion arranged at the lower end of the diaphragm and a valve seat portion provided at the flow path opening in the valve chamber are brought into contact with and separated from each other, and this contact and separation realizes opening and closing of the flow path including the valve seat portion and changing the size of the flow path.

[0003] In such a diaphragm valve, the problem is how to prevent particle generation due to contact and separation between the valve body and the valve seat. That is, particles can be said to be particles that are formed by the wear or the like of the materials that constitute the parts that constitute the diaphragm valve. If particles are generated in the valve body or the valve seat, which are in the liquid contact area, they will be mixed into the chemical liquid flowing through the diaphragm valve. Therefore, if the above-mentioned chemical liquid is, for example, a cleaning liquid used in semiconductor manufacturing, the cleaning liquid will contain particles, which will cause a problem of reduced cleanliness due to cleaning. To address this problem, the technology described in the following Patent Document 1 is known. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-034749 A Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned Patent Document 1 discloses a flow control valve in which the flow path side body and the valve body are formed from a fluororesin made of PFA or PTFE, and annular or circular sealing members made of cross-linked PTFE are joined to the valve body side abutment part and the valve seat side abutment part, with the aim of achieving excellent abrasion resistance and reducing the amount of dust generated. However, because cross-linked PTFE is harder than non-cross-linked PTFE or PFA, when a valve disc portion, only the surface of which is made of cross-linked PTFE, and a valve seat portion are brought into contact with and separated from each other, the non-cross-linked portion deforms, creating areas where the surface of the valve disc portion and the surface of the valve seat portion slide against each other. As a result, there is a problem that particles are still generated in these sliding areas.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a diaphragm valve and a manufacturing method thereof that can further suppress the generation of particles compared to conventional diaphragm valves. [Means for solving the problem]

[0007] That is, the present invention includes the following. [1] A diaphragm valve including a valve body portion and a membrane portion extending outward from the valve body portion and deformable in a movement axis direction, and a body having a valve seat portion against which the valve body portion abuts and separates as the membrane portion reciprocates in the movement axis direction due to deformation of the valve body portion, One of the valve body portion and the valve seat portion is provided with a rib protruding toward the other, The rib is made of cross-linked PFA from its tip to its base, A diaphragm valve characterized in that, when a tertiary carbon concentration at the tip is M1 (mol %) and a tertiary carbon concentration at the base is M2 (mol %), M1≧0.01, M2≧0.01, and 0.8≦M1 / M2≦1.2 are satisfied. [2] Either the diaphragm or the body, whichever of the parts has the rib, A base made of a non-crosslinked fluororesin; The diaphragm valve described in [1] above, having an end portion that is integral with the base, has the rib, and is made of the cross-linked PFA. [3] A diaphragm valve as described in [1] or [2] above, wherein the distance between the tip and the base of the rib is 250 μm or more. [4] The other of the valve body and the valve seat has an abutment portion that abuts against the rib provided on the one of the components, The diaphragm valve according to any one of [1] to [3] above, wherein the abutment portion is made of a cross-linked fluororesin. [5] A diaphragm valve described in any one of [1] to [4] above, wherein the rib is made of a remolded piece of cross-linked PFA film cross-linked so that the tertiary carbon concentration is 0.01 mol % or more. [6] The diaphragm valve described in [2] above, wherein one of the parts is cut from a composite material formed by integrating an intermediate material made of non-crosslinked fluororesin that serves as the base and a remolded piece of crosslinked PFA film that has been crosslinked so that the tertiary carbon concentration is 0.01 mol % or more. [7] A method for manufacturing a diaphragm valve according to any one of [1] to [6] above, A cutting step of obtaining cut pieces of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more; a remolding step of remolding the cut pieces to obtain a remolded product; and obtaining the rib from the remolded product. [8] A method for manufacturing the diaphragm valve described in [7] above, comprising an integration step of obtaining a composite material by integrating an intermediate material made of a non-crosslinked fluororesin with the remolded product. [9] The integration step includes a cut piece receiving step of receiving the cut piece in a cavity provided in the intermediate material; A manufacturing method for the diaphragm valve described in [8] above, comprising: a firing process for melting the cut piece in the cavity to obtain the remolded product and integrating the intermediate material with the remolded product.

[10] A method for manufacturing a diaphragm valve as described in [8] or [9] above, wherein the integration process includes an injection process of injecting a molten material of the cut piece into a cavity formed in the intermediate material to obtain the remolded product within the cavity and integrate the intermediate material with the remolded product.

[11] The integrating step includes a cut piece receiving step of receiving the cut piece in a cavity provided in the intermediate material; A method for manufacturing a diaphragm valve described in any one of [8] to

[10] above, comprising a compression molding process of compressing the cut piece in the cavity to obtain the remolded product and integrating the intermediate material with the remolded product.

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

[11] above, comprising a welding step for obtaining a composite material by welding an intermediate material made of a non-crosslinked fluororesin and the remolded product obtained in advance. Effect of the Invention

[0008] The diaphragm valve of the present invention can further suppress the generation of particles compared to conventional diaphragm valves.

[0009] That is, in a diaphragm valve in which the rib is made of cross-linked PFA from the tip to the base, and the tertiary carbon concentration M1 (mol%) at the tip and the tertiary carbon concentration M2 (mol%) at the base satisfy M1≧0.01, M2≧0.01, and 0.8≦M1 / M2≦1.2, the rib is formed of sufficiently cross-linked cross-linked PFA from the tip to the base, so that deformation of the rib is prevented when one part having the rib comes into contact with the other part. As a result, the diaphragm valve of the present invention can suppress the generation of particles, compared to a diaphragm valve that does not satisfy the above relationship between M1 and M2.

[0010] In the above diaphragm valve, one of the ribbed parts, either the diaphragm or the body, may have a base made of non-crosslinked fluororesin and an end part made of crosslinked PFA, which is integrated with the base and has ribs. In this case, since a non-crosslinked fluororesin having better flexural durability than crosslinked PFA can be used as the base, the flexural durability of the membrane part of the diaphragm can be particularly excellent. In addition, since it is not necessary to form the entire diaphragm or body from crosslinked PFA, the manufacturing cost of the diaphragm valve can be reduced.

[0011] In the above diaphragm valve, the rib 31 can have a distance D1 (see FIG. 2) between the tip 31a and the base 31b of 250 μm or more. Normally, it is difficult to crosslink a thick non-crosslinked PFA from the front to the back in terms of radiation transmittance, but this can be achieved by a manufacturing method for a diaphragm valve described later. By providing a rib with the distance of 250 μm or more, more reliable flow control can be achieved than with a rib with the distance of less than 250 μm.

[0012] In the above diaphragm valve, the other of the valve body and the valve seat has an abutment portion that abuts against a rib provided on the other of the parts, and the abutment portion can be made of cross-linked fluororesin. In this case, cross-linked fluororesin with excellent wear resistance is used as the mating material, resulting in a diaphragm valve with even greater durability.

[0013] In the above diaphragm valve, the rib can be made of a remolded piece of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more. That is, it is difficult to crosslink a thick non-crosslinked PFA film so that the tertiary carbon concentration is 0.01 mol% or more over the entire front and back from the viewpoint of radiation transmittance, but it is possible to obtain a crosslinked PFA film with a tertiary carbon concentration of 0.01 mol% or more over the entire front and back by irradiating a non-crosslinked PFA film of a thickness that allows this to be done. In addition, if the member is made of crosslinked PFA remolded from the cut piece cut from this crosslinked PFA film, it can be a crosslinked PFA member that is crosslinked uniformly throughout, regardless of its thickness. By forming the rib from such a crosslinked PFA member with a uniform degree of crosslinking throughout, deformation of the rib itself can be prevented, and particle generation accompanying contact and separation between the valve body portion and the valve seat portion can be significantly suppressed.

[0014] In the above diaphragm valve, one of the parts can be cut from a composite material that integrates an intermediate material made of a non-crosslinked fluororesin as a base and a remolded cut piece of a crosslinked PFA film that has been crosslinked so that the tertiary carbon concentration is 0.01 mol% or more. In this case, since a non-crosslinked fluororesin that has better flexural durability than crosslinked PFA can be used as the base, the flexural durability of the membrane part of the diaphragm can be particularly excellent. In addition, since it is not necessary to form the entire diaphragm or body from crosslinked PFA, the manufacturing cost of the diaphragm valve can be reduced.

[0015] According to the method for manufacturing a diaphragm valve of the present invention, it is possible to manufacture a diaphragm valve which can further suppress the generation of particles as compared to conventional diaphragm valves.

[0016] When the method includes a cutting step of obtaining a cut piece of a crosslinked PFA film crosslinked to have a tertiary carbon concentration of 0.01 mol% or more, a remolding step of remolding the cut piece to obtain a remolded product, and a forming step of obtaining a rib from the remolded product, a crosslinked PFA film that is uniformly crosslinked to have a tertiary carbon concentration of 0.01 mol% or more can be obtained. Then, by remolding the cut piece of the uniformly crosslinked crosslinked PFA film, a remolded product (crosslinked PFA member) made of crosslinked PFA that is uniformly crosslinked throughout the entire product to have a tertiary carbon concentration of 0.01 mol% or more can be obtained. By forming a rib from such a crosslinked PFA member that is uniformly crosslinked throughout the entire product, deformation of the rib itself can be prevented, and a diaphragm valve that can significantly suppress particle generation associated with contact and separation between the valve body and the valve seat can be obtained.

[0017] The above-mentioned manufacturing method of the diaphragm valve can include an integration step of obtaining a composite material by integrating an intermediate material made of a non-crosslinked fluororesin with a remolded product. In this case, since a non-crosslinked fluororesin having superior flexural durability compared to crosslinked PFA can be used, the intermediate material portion of the composite material can form the membrane portion of the diaphragm, and the membrane portion can have excellent flexural durability. In addition, since it is not necessary to form the entire diaphragm or body from crosslinked PFA, the manufacturing cost of the diaphragm valve can be reduced.

[0018] In the above-mentioned manufacturing method of the diaphragm valve, the integration step can include a cut piece accommodation step of accommodating the cut pieces in a cavity provided in the intermediate material, and a firing step of melting the cut pieces in the cavity to obtain a remolded product and integrate the intermediate material and the remolded product. In addition, in the above-mentioned manufacturing method of the diaphragm valve, the integration step can include an injection step of injecting the melted cut pieces into the cavity provided in the intermediate material to obtain a remolded product in the cavity and integrate the intermediate material and the remolded product. In addition, in the above-mentioned manufacturing method of the diaphragm valve, the integration step can include a cut piece accommodation step of accommodating the cut pieces in a cavity provided in the intermediate material, and a compression molding step of compressing the cut pieces in the cavity to obtain a remolded product and integrate the intermediate material and the remolded product. In addition, in the above-mentioned manufacturing method of the diaphragm valve, a welding step can be provided to obtain a composite material by welding the intermediate material made of a non-crosslinked fluororesin and the previously obtained remolded product. By carrying out these steps, a composite material can be obtained that integrates the intermediate material made of non-crosslinked fluororesin and the remolded product, and therefore, as described above, a diaphragm can be obtained that has a rib entirely made of uniformly crosslinked crosslinked PFA and also has a membrane part with excellent bending durability. In addition, since it is not necessary to form the entire diaphragm or body from crosslinked PFA, the manufacturing cost of the diaphragm valve can be reduced. [Brief description of the drawings]

[0019] The present invention will be further described in the following detailed description by way of non-limiting examples of exemplary embodiments according to the invention and with reference to the several drawings mentioned, in which like reference numerals refer to like parts throughout the several views of the drawings.

[0020] [Figure 1] FIG. 2 is a vertical cross-sectional view of the diaphragm valve of the first embodiment. [Diagram 2] FIG. 2 is a vertical cross-sectional view of a diaphragm that constitutes a diaphragm valve. [Diagram 3] FIG. 2 is a vertical cross-sectional view of a body that constitutes a diaphragm valve. [Figure 4]1A and 1B are diagrams illustrating the operation of a diaphragm valve, in which (a) shows a closed valve state and (b) shows an open valve state. [Diagram 5] FIG. 1 is an explanatory diagram for explaining a manufacturing method of a diaphragm valve, in which (a) shows a cross-linked PFA film, (b) shows a cutting process of the cross-linked PFA film, and (c) shows a remolding process of the cut pieces of the cross-linked PFA film. [Figure 6] FIG. 1 is an explanatory diagram for explaining a manufacturing method of a diaphragm valve (a process for integrating an intermediate material and a remolded product), in which (a) shows a perspective view of the intermediate material and the remolded product, and (b) shows a longitudinal sectional view of the remolded product contained in the cavity of the intermediate material. [Figure 7] FIG. 1 is an explanatory diagram for explaining a manufacturing method of a diaphragm valve (a rib forming process), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a diaphragm obtained by cutting the composite material. [Figure 8] 1A and 1B are explanatory diagrams for explaining a manufacturing method for another type of diaphragm valve (rib formation process), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a diaphragm obtained by cutting the composite material. [Figure 9] FIG. 11 is an explanatory diagram for explaining a manufacturing method for a diaphragm valve of still another embodiment (rib forming process), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a diaphragm obtained by cutting the composite material. [Figure 10] FIG. 11 is an explanatory diagram for explaining a manufacturing method for a diaphragm valve of still another embodiment (rib forming process), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a diaphragm obtained by cutting the composite material. [Figure 11] FIG. 11 is an explanatory diagram for explaining a manufacturing method of a diaphragm valve of still another embodiment (a process of integrating an intermediate material and a remolded product). [Figure 12] FIG. 11 is a vertical cross-sectional view of a diaphragm valve according to a second embodiment. [Figure 13] FIG. 2 is a vertical cross-sectional view of a diaphragm that constitutes a diaphragm valve. [Figure 14] FIG. 2 is a vertical cross-sectional view of a body that constitutes a diaphragm valve. [Figure 15] 1A and 1B are diagrams illustrating the operation of a diaphragm valve, in which (a) shows a closed valve state and (b) shows an open valve state. [Figure 16] 1A and 1B are explanatory diagrams for explaining a manufacturing method of a diaphragm valve, in which (a) shows a cross-linked PFA film, (b) shows a cutting process of the cross-linked PFA film, and (c) shows a remolding process of the cut pieces of the cross-linked PFA film. [Figure 17] FIG. 1 is an explanatory diagram for explaining a manufacturing method of a diaphragm valve (a process for integrating an intermediate material and a remolded product), in which (a) shows a perspective view of the intermediate material and the remolded product, and (b) shows a longitudinal sectional view of the remolded product contained in the cavity of the intermediate material. [Figure 18] 1A and 1B are explanatory diagrams for explaining a manufacturing method of a diaphragm valve (a rib forming process), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a body obtained by cutting the composite material. [Figure 19] 1A and 1B are explanatory diagrams for explaining a manufacturing method of another type of diaphragm valve (rib forming process), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a body obtained by cutting the composite material. [Figure 20] FIG. 11 is an explanatory diagram for explaining a manufacturing method for a diaphragm valve of still another embodiment (rib forming process), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a body obtained by cutting the composite material. [Figure 21] FIG. 11 is an explanatory diagram for explaining a manufacturing method for a diaphragm valve of still another embodiment (rib forming process), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a body obtained by cutting the composite material. [Figure 22] FIG. 11 is an explanatory diagram for explaining a manufacturing method for a diaphragm valve of still another embodiment (rib forming process), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a body obtained by cutting the composite material. [Diagram 23] FIG. 11 is an explanatory diagram for explaining a manufacturing method of a diaphragm valve of still another embodiment (a process of integrating an intermediate material and a remolded product). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The matters shown herein are illustrative and are intended to exemplify the embodiments of the present invention, and are described for the purpose of providing what is believed to be the most effective and easily understandable explanation of the principles and conceptual features of the present invention. In this respect, it is not intended to show structural details of the present invention beyond the extent necessary for a fundamental understanding of the present invention, and the description in conjunction with the drawings will make it clear to those skilled in the art how some forms of the present invention can be actually embodied.

[0022] The present invention will be specifically described below with reference to the drawings and examples 1 and 2.

[0023] <Example 1> As shown in Fig. 1, the diaphragm valve 1A of this embodiment comprises a diaphragm 3 having a valve body portion 3a and a membrane portion 3b extending outward from the valve body portion 3a and deformable in the direction of the movement axis C, and a body 5 having a valve seat portion 5a against which the valve body portion 3a abuts and separates as it reciprocates in the direction of the movement axis C due to deformation of the membrane portion 3b (see Fig. 4). Furthermore, the diaphragm valve 1A comprises a drive portion 7 that drives the diaphragm 3.

[0024] The body 5 is formed with a valve chamber 11 at the center of the upper part, and with a first flow path and a second flow path communicating with the valve chamber 11. The body 5 is also formed with an annular valve seat portion 5a around the opening from the first flow path to the valve chamber 11, with which the diaphragm 3 (specifically, the valve body portion 3a) comes into contact and separates. In this embodiment, the first flow path is formed with an inlet flow path 13 that extends from an inlet port 12 formed on one of the opposing side surfaces of the body 5 and opens 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. The second flow path is formed with an outlet flow path 15 that extends from an outlet port 14 formed on the other of the opposing side surfaces of the body 5 and opens at the side surface of the valve chamber 11. However, the first and second flow paths are not limited to the above-mentioned configuration, and may be, for example, a configuration in which a wear portion (dam portion) where a diaphragm comes into contact with and separates from each flow path is provided between the flow paths, or a configuration in which each flow path is arranged in a straight line may be adopted. Also, 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 may have three or more flow paths.

[0025] The drive unit 7 is attached to the upper part of the body 5. The drive unit 7 also includes a drive unit housing 17 having a mechanism accommodating space formed therein, a cover member 18 attached to the upper part of the drive unit housing 17, a stem 19 connected to the diaphragm 3, and a drive mechanism housed in the mechanism accommodating space and driving the stem 19. In this embodiment, a cylinder portion is formed in the drive unit housing 17 as the mechanism accommodating space, and the drive mechanism is composed of a piston 21 housed in the cylinder portion, and a coil spring 22 as a biasing member.

[0026] The piston 21 has a piston body 21a slidably accommodated in the cylinder part of the drive unit housing 17, and a guide shaft 21b extending upward from the piston body 21a. A stem 19 is connected to the piston body 21a so as to extend downward from the piston body 21a. The piston body 21a has an outer circumferential surface that is in contact with the inner circumferential surface of the cylinder part so as to be slidable in the vertical direction, and divides the internal space of the cylinder part into an upper space S1 surrounded by the upper surface of the piston body 21a, the inner circumferential wall of the cylinder part, and the ceiling surface of the cylinder part (i.e., the lower surface of the cover member 18), and a lower space S2 surrounded by the lower surface of the piston body 21a, the inner circumferential wall of the cylinder part, and the bottom surface of the cylinder part (i.e., the bottom of the drive unit housing 17). The guide shaft 21b is slidably inserted into a through hole provided through the cover member 18, and is adapted to guide the vertical movement of the piston 21. The stem 19 is slidably inserted into a through hole provided through the bottom of the drive unit housing 17 , extends to the valve chamber 11 , and has its tip connected to the diaphragm 3 .

[0027] The cover member 18 is formed with an air vent 26 that communicates with the cylinder section that defines the upper space S1. Air can be ventilated between the upper space S1 and the outside through the air vent 26. A working fluid supply port 27 that communicates with the bottom of the cylinder section that defines the lower space S2 is formed on the side of the drive unit housing 17. Working fluid can be supplied from the working fluid supply port 27 to the lower space S2. Furthermore, a coil spring 22 is arranged in a compressed state between the lower surface of the cover member 18 (i.e., the ceiling surface of the cylinder section) and the upper surface of the piston body 21a.

[0028] The driving unit 7 is not limited to the above-mentioned embodiment in which the diaphragm 3 is driven by using a fluid pressure, but may be an electric actuator having a motor, a solenoid, or the like, for example. Furthermore, the diaphragm 3 may be driven manually.

[0029] The diaphragm 3 is disposed so as to close the upper opening of the valve chamber 11, and is fixed to the body 5. The diaphragm 3 has a valve body portion 3a disposed in the center, an annular membrane portion 3b formed to be thin so as to be easily bent and supporting the valve body portion 3a, and an outer peripheral edge portion 3c disposed on the outer peripheral side of the membrane portion 3b (see FIG. 2). The valve body portion 3a has a shape like a truncated cone connected to a cylinder, that is, a cone shape with a tapered upper end. The valve body portion 3a is disposed so that its bottom surface faces the valve seat portion 5a. The bottom surface of the valve body portion 3a is provided with an annular rib 31 that protrudes toward the valve seat portion 5a. The membrane portion 3b is formed so as to extend radially outward from the outer peripheral portion of the upper end of the valve body portion 3a, and the outer periphery of the membrane portion 3b has a roughly circular shape. Furthermore, at least a portion of the outer peripheral edge portion 3c is sandwiched between the upper surface of the surrounding area of ​​the upper opening of the valve chamber 11 of the body 5 and the bottom surface of the actuator housing 17. In this manner, the diaphragm 3 separates the valve chamber 11 from the actuator 7 with the valve body portion 3a supported within the valve chamber 11 via the membrane portion 3b.

[0030] In addition, the shapes of the valve seat portion 5a, the valve body portion 3a and the rib 31 are not limited as long as the rib 31 of the valve body portion 3a, which moves back and forth in the direction of the movement axis C due to the deformation of the membrane portion 3b, can approach and separate from the valve seat portion 5a to open and close the communication between the first flow path (specifically, the inlet flow path 13) and the second flow path (specifically, the outlet flow path 15).

[0031] The valve body portion 3a of the diaphragm 3 is provided with a connecting hole 37 that opens upward. The connecting hole 37 includes a small diameter hole portion 37a located on the side closer to the drive unit 7, and a large diameter hole portion 37b that is continuous with the small diameter hole portion 37a below. The tip portion (lower end portion) of the stem 19 is provided with a locking portion 19a that is larger than the intermediate portion, and the diaphragm 3 and the stem 19 are connected by pressing the locking portion 19a through the small diameter hole portion 37a into the large diameter hole portion 37b, so that the diaphragm 3 (specifically the valve body portion 3a) can approach and separate from the valve seat portion 5a via the stem 19 as the piston 21 moves up and down.

[0032] As shown in Fig. 2, the diaphragm 3 has a base 33a made of a non-crosslinked fluororesin, and an end 33b made of crosslinked PFA, which is integrated with the base 33a and has a rib 31. That is, the base 33a including the membrane portion 3b is made of a non-crosslinked fluororesin which is less expensive and has high bending durability than crosslinked PFA. The end 33b including the rib 31 (specifically, the bottom of the valve body portion 3a) is made of crosslinked PFA which has high abrasion resistance and strength. Furthermore, the diaphragm 3 is cut from a composite material 45 which is made by integrating an intermediate material 44 made of a non-crosslinked fluororesin which becomes the base 33a, and a remolded product 43 (remolded product 43 which becomes the end 33b) of a cut piece 42 of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more (see Figs. 5 to 7).

[0033] The type of fluororesin constituting the non-crosslinked fluororesin is not limited, and a polymer (homopolymer or copolymer) using a fluorine-substituted polymerizable compound as a monomer, such as tetrafluoroethylene [F2C=CF2], hexafluoropropene [F2C=CF2-CF3], difluoroethylene [H2C=CF2], chlorotrifluoroethylene [F2C=CFCl], perfluoroalkoxyethylene (perfluoromethoxyethylene [F2C=CF-O-CF3], perfluoroethoxyethylene [F2C=CF-O-CF2-CF2], etc.), can be used. Among these, ethylene (non-fluorine-substituted ethylene) can be used as a copolymer monomer. Specifically, for example, PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane, tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin), FEP (tetrafluoroethylene-hexafluoropropene copolymer resin), ETFE (ethylene-tetrafluoroethylene copolymer resin), PVDF (polyvinylidene fluoride, difluoroethylene polymer), PCTFE (polychlorotrifluoroethylene), ECTFE (ethylene-chlorotrifluoroethylene copolymer resin), etc. can be used. These may be used alone or in combination of two or more. Among these, non-crosslinked PTFE is preferable as the base 33a from the viewpoints of suppressing melting due to heating, maintaining the shape by gelation, and reducing material costs.

[0034] Moreover, crosslinking in fluororesin means that different polymer molecules constituting the fluororesin form carbon-carbon bonds. Therefore, non-crosslinked PFA usually does not have tertiary carbon, but crosslinked PFA does. Therefore, the presence or absence of tertiary carbon corresponds to the presence or absence of crosslinking in PFA, and it can be seen that the higher the tertiary carbon concentration, the more crosslinks there are in PFA. In the present invention, crosslinking is considered to occur when the tertiary carbon concentration is 0.01 mol% or more. The upper limit of this tertiary carbon concentration is not limited, but is usually 0.7 mol% or less. By maintaining the tertiary carbon concentration at 0.7 mol% or less, the mechanical strength of the crosslinked PFA can be maintained high.

[0035] Tertiary carbon concentration of cross-linked PFA 19 F-NMR measurement (measurement device: solid 19 The integral values ​​of the peaks A to G shown in Table 1 below are measured by F-NMR (Bruker Biospin AVANCE III-400WB, measurement conditions: 376 MHz, rotation speed 27 kHz), and then calculated (based on peak C) using the following calculation formula (1). The presence of tertiary carbon can be determined by the presence of peak C and / or peak G, but as described above, the tertiary carbon concentration is basically calculated according to formula (1) using the peak intensity of peak C. However, when peak C is not detected and only peak G is detected, the tertiary carbon concentration is calculated using formula (2) below. The tertiary carbon concentration calculated by formula (1) and the tertiary carbon concentration calculated by formula (2) are usually substantially the same value.

[0036] In addition, the following formula [I A / 3 ], [I B / 5 ], [I C / 6 ], [I D / 4 ], [I E / 2 ], [I F / 1 ] and [I G / 1 ] are as follows: [I A / 3 ]: Equivalent F in the structure of "A" in Table 1 * Since there are three peaks, the peak intensity based on "A" is "I A ", then one F in "A" * The peak intensity for I A / 3" and this value is [I A / 3 ] should be written. [I B / 5 ]: Equivalent F in the structure of "B" in Table 1 * Since there are five, the peak intensity based on "B" is "I B ", then one F in "B" * The peak intensity for I B / 5" and this value is [I B / 5 ] should be written. [IC / 6 ]: Equivalent F in the structure of "C" in Table 1 * Since there are six peaks, the peak intensity based on "C" is "I C ", then one F in "C" * The peak intensity for I C / 6" and this value is [I C / 6 ] should be written. [I D / 4 ]: Equivalent F in the structure of "D" in Table 1 * Since there are four, the peak intensity based on "D" is "I D ", then one F in "D" * The peak intensity for I D / 4" and this value is [I D / 4 ] should be written. [I E / 2 ]: Equivalent F in the structure of "E" in Table 1 * Since there are two, the peak intensity based on "E" is "I E ", then one F in "E" * The peak intensity for I E / 2" and this value is [I E / 2 ] should be written. [I F / 1 ]: Equivalent F in the structure of "F" in Table 1 * Since there is only one, the peak intensity based on "F" is "I F ", then one F in "F" * The peak intensity for I F / 1" and this value is [I F / 1 ] should be written. [I G / 1 ]: Equivalent F in the structure of "G" in Table 1 * Since there is only one, the peak intensity based on "G" is "I G ", then one F in "G" * The peak intensity for I G / 1" and this value is [I G / 1 ] should be written.

[0037] [Formula (1)]I C / 6 Tertiary carbon concentration based on 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 [Formula (2)]I G / 1 Tertiary carbon concentration based on Tertiary carbon concentration (mol%) = {[I G / 1 ]-[I A / 3 ]} / {[I B / 5 ]+[I C / 6 ]+[I D / 4 ]+[I E / 2 ]+[I F / 1 ]}×100

[0038] [Table 1]

[0039] The rib 31 is made of cross-linked PFA from its tip to its base, and satisfies M1>0.01, M2>0.01, and 0.8≦M1 / M2≦1.2, where M1 (mol%) is the tertiary carbon concentration at the tip and M2 (mol%) is the tertiary carbon concentration at the base. That is, the rib 31 has a tertiary carbon concentration M1 at its tip that exceeds 0.01 mol%, and at the same time, the tertiary carbon concentration M2 at its base also exceeds 0.01 mol%. In addition, the ratio (M1 / M2) of M1 to M2 is 0.8 or more and 1.2 or less, and M1 and M2 are close values. Therefore, the rib 31 is formed of cross-linked PFA that is uniformly cross-linked from its tip to its base. In addition, the distance between the tip and base of the rib 31 is about 250 to 2000 μm, and is set to 250 μm or more.

[0040] The rib 31 made of cross-linked PFA that is uniformly cross-linked from tip to base may be formed in any manner, but can be formed from a remolded product 43 of a cut piece 42 of a cross-linked PFA film that has been cross-linked so that the tertiary carbon concentration is 0.01 mol % or more (see Figure 5). That is, for example, in the case of a thin film-like non-crosslinked PFA of less than 250 μm, radiation can be irradiated so as to reach both sides of the film. On the other hand, for example, in the case of a thick film-like non-crosslinked PFA of 250 μm or more, it becomes difficult to transmit radiation, and a crosslinked PFA film with different degrees of crosslinking on the front and back is formed. In addition, the output of radiation can be increased to transmit the front and back of the non-crosslinked PFA film, but as a result, the degree of crosslinking on the front and back may differ due to attenuation during transmission, and the use of high-output radiation leads to a rapid increase in costs, making it difficult to adopt. Therefore, in order to obtain a crosslinked PFA that is low-cost and has a high degree of freedom in shape while reliably crosslinking, radiation is irradiated to a thin film-like non-crosslinked PFA of less than 250 μm so as to reach both sides of the film, the film is uniformly crosslinked, and then the cut pieces 42 obtained by cutting the film are remolded, whereby a crosslinked PFA having a desired shape that is uniformly crosslinked can be obtained. Furthermore, for example, among fluororesins, PTFE is difficult to melt-form, regardless of whether it is crosslinked or not. On the other hand, since PFA can be melt-molded even after crosslinking, it is possible to obtain a block of crosslinked PFA by remolding the cut piece 42 of the crosslinked PFA film.

[0041] On the other hand, the valve seat portion 5a of the body 5 is provided with an abutment portion 39 against which the rib 31 provided on the valve body portion 3a of the diaphragm 3 abuts. The abutment portion 39 is formed of an annular surface portion. However, the shape of the abutment portion 39 is not limited as long as the rib 31 can abut. As shown in FIG. 3, the body 5 has a base portion 35a made of a non-crosslinked fluororesin, and an end portion 35b made of a crosslinked fluororesin, which is integrated with the base portion 35a and has the abutment portion 39. That is, the base portion 35a (specifically, a portion of the body 5 having a larger volume than the end portion 35b) is made of a non-crosslinked PTFE, which is cheaper than a crosslinked fluororesin. The end portion 35b, including the abutment portion 39, is made of a crosslinked fluororesin, which has high abrasion resistance and strength. The non-crosslinked fluororesin constituting the base 35a may be any of the above-mentioned non-crosslinked fluororesins, while the crosslinked fluororesin constituting the end 35b may be any of the above-mentioned crosslinked fluororesins, with crosslinked PFA being particularly preferred.

[0042] Next, a method for manufacturing the diaphragm valve 1A having the above configuration will be described. First, the intermediate material 44 having a cylindrical cavity 44a is made from a non-crosslinked fluororesin. PTFE can be used as this non-crosslinked fluororesin. In the first embodiment, as shown in Fig. 6, a cup-shaped intermediate material 44 having a recess functioning as a cavity 44a at the upper end is produced. The intermediate material 44 may be formed by any method, but may be produced, for example, by forming a recess by cutting at the upper end of a rod-shaped body or plate compression-molded from a non-crosslinked fluororesin using a mold by a free baking method, hot molding method, etc. Similarly, the intermediate material 44 may be produced by compression-molding a cup-shaped rod-shaped body or plate having a recess at the upper end from a non-crosslinked fluororesin using a mold by a free baking method, hot molding method, etc. Moreover, the intermediate material 44 does not need to be integrally formed, and can be produced, for example, by combining a cylindrical tubular body with a solid rod-shaped body or plate-shaped body (including a sheet-shaped body) disposed adjacent to the lower part of the cylindrical tubular body. In this case, the tubular body and the rod-shaped body or plate-shaped body may be joined by screwing or uneven fitting. Furthermore, when the tubular body and the rod-shaped body or plate-shaped body (including a sheet-shaped body) are integrally formed, they may be produced separately and then joined by welding. The welding can be performed, for example, by laser welding, hot plate welding, hot air welding, heating block welding, diffusion bonding, baking, etc. When the intermediate material 44 is produced from a rod-shaped body of non-crosslinked fluororesin, the rod-shaped body of non-crosslinked fluororesin may be produced by extrusion molding.

[0043] On the other hand, a remolded object 43 having a shape and size that can be accommodated in the cavity 44a (recess) of the intermediate material 44 as shown in Fig. 6 is produced from the cross-linked PFA (remolding step). The remolded object 43 may be remolded in a place other than the cavity 44a, or may be remolded inside the cavity 44a. When remolding at a location other than the cavity 44a, a rod-shaped body whose outer peripheral shape is complementary to the inner peripheral surface of the cylindrical cavity 44a can be remolded from the crosslinked PFA in the same manner as the intermediate material 44 described above. In this case, a cut piece 42 of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more can be used as the raw material for the crosslinked PFA. That is, for example, as shown in FIG. 5(a), a crosslinked PFA film 41 can be formed by irradiating a film made of non-crosslinked PFA (non-crosslinked PFA film) with radiation. That is, by irradiating a thin non-crosslinked PFA formed in a film shape with radiation, a crosslinked PFA film that is uniformly crosslinked on both sides can be obtained. More specifically, by irradiating the uncrosslinked PFA film to be irradiated with radiation at an accelerating voltage such that the absorbed dose on the back side of the irradiated surface is 20% or more (preferably 60% or more) of the absorbed dose on the front side relative to the thickness of the uncrosslinked PFA film to be irradiated in a temperature environment above the melting point of the uncrosslinked PFA, a crosslinked PFA film having a tertiary carbon concentration of 0.01 mol % or more across both sides of the film can be obtained.

[0044] Thereafter, as shown in FIG. 5(b), the crosslinked PFA film that has been uniformly crosslinked on both sides is cut to obtain cut pieces 42, thereby obtaining a crosslinked PFA material with a higher degree of freedom in shape. Furthermore, as shown in FIG. 5(c), the cut pieces 42 of the crosslinked PFA film are placed in a cavity of a mold 46 having a predetermined shape, and are then heated and melted, followed by solidification to obtain a remolded product 43. This remolded product 43 can be placed in the cavity 44a of the intermediate material 44 after being shaped by cutting or the like so that it can be placed in the cavity 44a. Also, for example, from the viewpoint of being able to heat and melt it, the height of the remolded product 43 may be approximately equal to the depth of the cavity 44a, or may be shorter than the depth of the cavity 44a, so long as it does not overflow from the cavity 44a when heated and melted. The remolded product 43 can also be directly produced from the crosslinked PFA by extrusion molding or injection molding using a mold, for example.

[0045] On the other hand, when remolding the remolded product 43 inside the cavity 44a, as shown in FIG. 11, the cut pieces 42 of the cross-linked PFA film described above are placed in the cavity 44a (cut piece placement process), and are heated and melted in the cavity 44a to obtain the remolded product 43 made of cross-linked PFA having a shape complementary to the inner surface of the cavity 44a. In this case, only the cut pieces 42 of the crosslinked PFA film housed in the cavities 44a can be heated and melted, but the cavity 44a can also be heated. That is, for example, the entire intermediate material 44 can be heated. This method is preferably used when the intermediate material 44 is made of non-crosslinked PTFE. The non-crosslinked PTFE is gelled and not melted even at a temperature at which the crosslinked PFA is heated and melted. Therefore, the general shapes of the intermediate material 44 and the cavity 44a can be maintained. Then, after the cut pieces 42 of the crosslinked PFA film are heated and melted, they are remolded into a shape corresponding to the cavity 44a, and then cooled and solidified, and at the same time, the cavity 44a is also cooled and solidified, and at that time, the two (the intermediate material 44 and the remolded product 43) are integrated, and a composite material 45 of these is obtained (firing process).

[0046] In this way, when the remolded object 43 is remolded inside the cavity 44a, the production of the remolded object 43 and the integration of the obtained remolded object 43 with the intermediate material 44 can be realized by one heating, melting, cooling and solidification, so that excellent manufacturing efficiency can be achieved. In addition, since a mold for obtaining the remolded object 43 is not required, the diaphragm valve can be manufactured at low cost. Furthermore, when the remolded object 43 is obtained in the cavity 44a while heating the entire intermediate material 44, the occurrence of distortion and residual stress can be suppressed, so that excellent bonding strength can be obtained between the two. This effect can be obtained more remarkably by performing heating under no pressure (in a state where no pressure is particularly applied). In addition, when the remolded object 43 is remolded inside the cavity 44a, the cavity 44a and the remolded object 43 can be bonded over the entire contact surface, so that the intermediate material 44 and the remolded object 43 can be bonded more firmly than a composite material having selective bonding points such as laser welding. Moreover, even if an external force acts on the composite material 45, it is possible to prevent a gap from being generated between them. As described above, a rod-shaped composite material 45 obtained by remolding the remolded object 43 inside the cavity 44a was used as a test piece, and a tensile test was performed by setting the intermediate material 44 and the remolded object 43 so as to separate them.It was confirmed that the joint between the intermediate material 44 and the remolded object 43 did not break, but broke at a location other than the joint.

[0047] In addition, when obtaining crosslinked PFA, it is also possible to select, for example, non-crosslinked PFA powder as a starting material without using a non-crosslinked PFA film. However, when crosslinked PFA powder is obtained from non-crosslinked PFA powder, the crosslinked PFA powder is remolded, but there is a problem that the melt is likely to contain gas when heated and melted. That is, the melt viscosity of crosslinked PFA is higher than that of non-crosslinked PFA, and the higher the degree of crosslinking, the higher the melt viscosity. Therefore, when trying to obtain abrasion resistance with priority, it requires time and cost for degassing, so it is preferable to use cut pieces of crosslinked PFA film from the viewpoint of excellent degassing ability during heat melting. In addition, crosslinked PFA film can be crushed into, for example, powder or fine particles, but it is less expensive to use cut pieces. Furthermore, it is preferable to use cut pieces from the viewpoint of more effectively maintaining the mechanical strength obtained by crosslinking.

[0048] As described above, when the entire intermediate material 44 is heated and the cut pieces 42 accommodated in the cavity 44a are heated and melted to obtain the remolded product 43 (firing process), the integration process can be performed simultaneously with the cooling and solidification, but the same effect can be obtained by the following method. That is, for example, the melted cut pieces 42 of the cross-linked PFA film can be injected into the cavity 44a provided in the intermediate material 44 to obtain the remolded product 43 in the cavity 44a, and the intermediate material 44 and the remolded product 43 can be integrated using an injection process. Also, after accommodating the cut pieces 42 of the cross-linked PFA film in the cavity 44a provided in the intermediate material 44 (cut piece accommodation process), the cut pieces 42 can be compressed in the cavity 44a to obtain the remolded product 43 and integrate the intermediate material 44 and the remolded product 43 (compression molding process). Heating can be performed at the same time as this compression. The heating may be performed at a temperature as required. For example, the heating may be performed at a temperature lower than the melting point of the cross-linked PFA, or at a temperature higher than the melting point of the cross-linked PFA.

[0049] On the other hand, when the remolded object 43 is obtained separately, an integration step is performed to obtain a composite material 45 by integrating the intermediate material 44 with the remolded object 43 accommodated in the cavity 44a (recess) of the intermediate material 44. The integration may be performed by any method, but for example, the integration can be performed by simultaneously heating both to a temperature equal to or higher than the higher of the melting points of the non-crosslinked fluororesin constituting the intermediate material 44 and the crosslinked PFA constituting the remolded object 43. That is, the intermediate material 44 and the remolded object 43 can be joined by melting at least one of them at least on its surface.

[0050] The intermediate material 44 and the remolded product 43 can also be joined by welding. That is, this can be achieved by providing a welding process for obtaining a composite material by welding the intermediate material 44 and the remolded product 43. This welding can be performed by, for example, laser welding, hot plate welding, hot air welding, heating block welding, diffusion bonding, etc. Each of these methods can be said to be a method of melting at least a part of the contact area between the intermediate material 44 and the remolded product 43 to weld them together.

[0051] 7(a) to 7(b) show a method for producing a diaphragm 3 from a composite material 45. A diaphragm 3 as shown in FIG. 7(b) can be produced by cutting a composite material 45 as shown by a broken line in FIG. 7(a). The diaphragm 3 shown in FIG. 7(b) is used in the diaphragm valve 1A shown in FIG. 1. In the diaphragm 3, a membrane portion 3b having a base portion 33a at the center is produced from an intermediate material 44 formed from a non-crosslinked fluororesin in the composite material 45. The non-crosslinked fluororesin constituting the intermediate material 44 is formed from PTFE from the viewpoint of high bending durability.

[0052] Moreover, the end 33b of the diaphragm 3 is formed of cross-linked PFA from the viewpoint of low dust generation. Moreover, in the composite material 45, the intermediate material 44 and the remolded product 43 are integrally bonded by sintering (integral melt molding). Therefore, the entire boundary surface (joint surface) between the base 33a and the end 33b of the diaphragm 3 is integrally bonded. Therefore, even if the end 33b abuts against the valve seat 5a when the valve is closed and is deformed by receiving an impact, no gap is generated at the boundary surface between the base 33a and the end 33b, and a decrease in strength due to the liquid in the valve chamber 11 entering the gap can be prevented. Moreover, since both the intermediate material 44 and the remolded product 43 are heated and then cooled overall, the occurrence of thermal strain is suppressed, and the decrease in strength due to thermal strain is also suppressed.

[0053] In addition, by cutting out the parts made from the composite material 45 from an appropriate position, it is possible to change which range of the parts is made from different fluororesins. That is, in Figs. 7(a) and 7(b), only the vicinity of the contact surface that contacts the valve seat portion 5a is made from cross-linked PFA, which has low dust generation, but for example, as shown in Figs. 8(a) and 8(b), by changing the cutting position, it is possible to make the end portion 33b made from cross-linked PFA larger and the base portion 33a made from non-cross-linked fluororesin smaller. On the other hand, as shown in Figs. 10(a) and 10(b), it is possible to make only the rib 31 from cross-linked PFA and make the other portions from non-cross-linked fluororesin. And, as shown in Figs. 10(a) and 10(b), when only the rib 31 is made from cross-linked PFA, it is possible to keep the size of the remolded object 43 in the composite material 45 small. Therefore, it is possible to obtain a diaphragm with excellent performance while reducing the amount of cross-linked PFA used, which is more expensive than non-cross-linked fluororesin.

[0054] Next, the action and effect of the diaphragm valve 1A having the above configuration will be described. As shown in FIG. 1, in normal times when the working fluid is not supplied from the working fluid supply port 27 to the drive unit 7, the piston 21 of the drive unit 7 is urged downward by the coil spring 22 and pushed down. As a result, the valve body portion 3a moves in a direction approaching the valve seat portion 5a via the stem 19, and the rib 31 of the valve body portion 3a is pressed against the valve seat portion 5a, and the diaphragm valve 1A is in a closed state (see FIG. 4(a)). Accordingly, the membrane portion 3b supporting the valve body portion 3a is also deformed in a direction away from the drive unit 7. When the 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 that has flowed into the lower space S2 of the cylinder portion acts upward on the piston body 21a, and the piston 21 is pushed up against the urging force of the coil spring 22. At this time, the air in the upper space S1 is discharged to the outside from the ventilation port 26. As a result, the valve body 3a is moved away from the valve seat 5a via the stem 19, and the diaphragm valve 1A is opened (see FIG. 4(b)). Accordingly, the membrane portion 3b is also deformed in a direction approaching the drive portion 7. When the supply of working fluid to the working fluid supply port 27 is stopped, the piston 21 is again urged downward by the coil spring 22 and pushed down, and the rib 31 of the valve body 3a is pressed against the valve seat 5a, and the valve is closed again.

[0055] As described above, according to the diaphragm valve 1A of this embodiment, the valve body portion 3a is provided with a rib 31 that protrudes toward the valve seat portion 5a, and the rib 31 is made of cross-linked PFA from its tip to its base, and when the tertiary carbon concentration at the tip is M1 (mol%) and the tertiary carbon concentration at the base is 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 cross-linked PFA that is uniformly cross-linked from its tip to its base, so that the wear resistance and strength of the rib 31 are improved. Therefore, when the rib 31 of the valve body portion 3a abuts against the valve seat portion 5a when the valve is closed, the rib 31 is prevented from deforming and rubbing against the valve seat portion 5a, and the amount of particles generated can be reduced.

[0056] <Example 2> Next, a diaphragm valve 1B of the second embodiment will be described, but the same components as those of the diaphragm valve 1A of the first embodiment will be designated by the same reference numerals and detailed description will be omitted, and the differences between the two will be described in detail. The main difference between the two is that, while a rib 31 is provided on the valve body portion 3a of the diaphragm 3 in the first embodiment, a rib 31 is provided on the valve seat portion 5a of the body 5 in the second embodiment.

[0057] As shown in Fig. 12, the diaphragm valve 1B of this embodiment comprises a diaphragm 3 having a valve body portion 3a and a membrane portion 3b extending outward from the valve body portion 3a and deformable in the direction of the movement axis C, and a body 5 having a valve seat portion 5a against which the valve body portion 3a abuts and separates as it reciprocates in the direction of the movement axis C due to deformation of the membrane portion 3b (see Fig. 15). Furthermore, the diaphragm valve 1B comprises a drive portion 7 that drives the diaphragm 3.

[0058] In the body 5, an annular valve seat portion 5a with which the diaphragm 3 (specifically, the valve body portion 3a) comes into contact and separates is formed around the opening from the first flow path to the valve chamber 11 (see FIG. 14). The valve seat portion 5a is provided with an annular rib 31 that protrudes toward the valve body portion 3a.

[0059] The shapes of the valve seat portion 5a, the valve body portion 3a and the rib 31 are not limited as long as the valve body portion 3a, which moves back and forth in the direction of the movement axis C due to deformation of the membrane portion 3b, can approach and separate from the rib 31 of the valve seat portion 5a to open and close the communication between the first flow path (specifically, the inlet flow path 13) and the second flow path (specifically, the outlet flow path 15).

[0060] As shown in Fig. 14, the body 5 has a base 35a made of a non-crosslinked fluororesin, and an end 35b made of crosslinked PFA, which is integrated with the base 35a and has a rib 31. That is, the base 35a (specifically, a portion of the body 5 having a larger volume than the end 35b) is made of a non-crosslinked fluororesin that is less expensive than crosslinked PFA. The end 35b including the rib 31 is made of crosslinked PFA that has high abrasion resistance and strength. Furthermore, the body 5 is cut from a composite material 45 that integrates an intermediate material 44 made of a non-crosslinked fluororesin that becomes the base 35a, and a remolded product 43 (i.e., the remolded product 43 that becomes the end 35b) of a cut piece 42 of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more (see Figs. 16 to 18).

[0061] The rib 31 is made of cross-linked PFA from its tip to its base, and when the tertiary carbon concentration at the tip is M1 (mol%) and the tertiary carbon concentration at the base is M2 (mol%), M1>0.01, M2>0.01, and 0.8≦M1 / M2≦1.2 are satisfied. Therefore, the rib 31 is made of cross-linked PFA that is uniformly cross-linked from its tip to its base, and has high abrasion resistance and strength.

[0062] The type of fluororesin constituting the non-crosslinked fluororesin is not limited, and a polymer (homopolymer or copolymer) using tetrafluoroethylene, hexafluoropropene, difluoroethylene, chlorotrifluoroethylene, perfluoroalkoxyethylene, or the like as a monomer can be used, as in the case of Example 1. Specifically, a polymer (homopolymer or copolymer) using a fluorine-substituted polymerizable monomer can be used, and specifically, PTFE, PFA, FEP, ETFE, PVDF, PCTFE, ECTFE, or the like can be adopted. These may be used alone or in combination of two or more. Among these, non-crosslinked PTFE is preferable as the base 35a from the viewpoints of suppressing melting due to heating, maintaining the shape by gelation, and reducing material costs.

[0063] On the other hand, the end 35b is formed from a cross-linked PFA having high abrasion resistance and strength, and the tertiary carbon concentration of the cross-linked PFA is preferably 0.01 mol% or more, and although there is no upper limit, it is usually 0.7 mol% or less, as in Example 1. The tertiary carbon concentration is also measured in the same manner as in Example 1.

[0064] In the case where the rib 31 is provided on the body 5, as in the case of the first embodiment, the rib 31 is made of cross-linked PFA from its tip to its base, and when the tertiary carbon concentration at the tip is M1 (mol%) and the tertiary carbon concentration at the base is M2 (mol%), M1>0.01, M2>0.01, and 0.8≦M1 / M2≦1.2 are satisfied. That is, the rib 31 has a tertiary carbon concentration M1 at its tip that exceeds 0.01 mol%, and at the same time, the tertiary carbon concentration M2 at its base that exceeds 0.01 mol%. In addition, the ratio (M1 / M2) of M1 to M2 is 0.8 or more and 1.2 or less, and M1 and M2 are close to each other. Therefore, the rib 31 is formed of cross-linked PFA that is uniformly cross-linked from its tip to its base. Moreover, the distance between the tip and base of the rib 31 is about 250 to 2000 μm, and is set to be 250 μm or more.

[0065] The rib 31 made of crosslinked PFA uniformly crosslinked from the tip to the base may be formed in any manner, but can be formed from a remolded product 43 of a cut piece 42 of a crosslinked PFA film, as in the case of Example 1 (see FIG. 16). In this case, the action and effect are also the same as in the case of Example 1. That is, as shown in FIG. 16(a), a crosslinked PFA film 41 is formed by irradiating a film made of non-crosslinked PFA (non-crosslinked PFA film) with radiation, and as shown in FIG. 16(b), the crosslinked PFA film uniformly crosslinked on both sides is cut to obtain a cut piece 42, and then, as shown in FIG. 16(c), the cut piece 42 of the crosslinked PFA film is placed in the cavity of a mold 46 having a predetermined shape, heated and melted, and then solidified to obtain a remolded product 43.

[0066] The bottom surface side of the valve body portion 3a of the diaphragm 3 is provided with an abutment portion 39 against which the rib 31 provided on the valve seat portion 5a of the body 5 abuts. The abutment portion 39 is formed of an annular surface portion. However, the shape of the abutment portion 39 is not limited as long as the rib 31 can abut. As shown in FIG. 13, the diaphragm 3 has a base portion 33a made of non-crosslinked PTFE and an end portion 33b that is integrated with the base portion 33a, has the abutment portion 39, and is made of a crosslinked fluororesin such as PTFE or PFA. That is, the base portion 33a including the membrane portion 3b is formed of non-crosslinked PTFE, which is cheaper and has higher bending durability than crosslinked fluororesin. The end portion 33b including the abutment portion 39 (specifically, the bottom portion of the valve body portion 3a) is formed of a crosslinked fluororesin that has high wear resistance and strength.

[0067] Next, a method for manufacturing the diaphragm valve 1B having the above-mentioned configuration will be described. First, as shown in Fig. 17(a) to Fig. 17(b), an intermediate material 44 having a cylindrical cavity 44a is prepared from a non-crosslinked fluororesin in the same manner as in Example 1. Meanwhile, as shown in Fig. 16(a) to Fig. 16(c), a remolded product 43 that can be accommodated in the cavity 44a (recess) is prepared using a cut piece 42 of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more. Then, the remolded product 43 is accommodated in the cavity 44a of the intermediate material 44, and by joining the two together by an appropriate method in the same manner as in Example 1, a composite material in which the intermediate material 44 and the remolded product 43 are integrated can be obtained.

[0068] On the other hand, as in the case of Example 1, when remolding the remolded product 43 inside the cavity 44a, as shown in Figure 23, the cut pieces 42 of the cross-linked PFA film are placed in the cavity 44a (cut piece placement process), and the cut pieces 42 are heated and melted in the cavity 44a, thereby obtaining the remolded product 43 made of cross-linked PFA having a shape complementary to the inner surface of the cavity 44a. In this case, only the cut pieces 42 of the crosslinked PFA film housed in the cavities 44a can be heated and melted, but the cavity 44a can also be heated. That is, for example, the entire intermediate material 44 can be heated. This method is preferably used when the intermediate material 44 is made of non-crosslinked PTFE. The non-crosslinked PTFE is gelled and not melted even at a temperature at which the crosslinked PFA is heated and melted. Therefore, the general shapes of the intermediate material 44 and the cavity 44a can be maintained. Then, after the cut pieces 42 of the crosslinked PFA film are heated and melted, they are remolded into a shape corresponding to the cavity 44a, and then cooled and solidified, and at the same time, the cavity 44a is also cooled and solidified, and at that time, the two (the intermediate material 44 and the remolded product 43) are integrated, and a composite material 45 of these is obtained (firing process).

[0069] In this way, when the remolded object 43 is remolded inside the cavity 44a, the production of the remolded object 43 and the integration of the obtained remolded object 43 with the intermediate material 44 can be realized by one heating, melting, cooling and solidification, so that excellent manufacturing efficiency can be achieved. In addition, since a mold for obtaining the remolded object 43 is not required, the diaphragm valve can be manufactured at low cost. Furthermore, when the remolded object 43 is obtained in the cavity 44a while heating the entire intermediate material 44, the occurrence of distortion and residual stress can be suppressed, so that excellent bonding strength can be obtained between the two. This effect can be obtained more remarkably by performing heating under no pressure (in a state where no pressure is particularly applied). In addition, when the remolded object 43 is remolded inside the cavity 44a, the cavity 44a and the remolded object 43 can be bonded over the entire contact surface, so that the intermediate material 44 and the remolded object 43 can be bonded more firmly than a composite material having selective bonding points such as laser welding. Moreover, even if an external force acts on the composite material 45, it is possible to prevent a gap from being generated between them. As described above, a rod-shaped composite material 45 obtained by remolding the remolded object 43 inside the cavity 44a was used as a test piece, and a tensile test was performed by setting the intermediate material 44 and the remolded object 43 so as to separate them.It was confirmed that the joint between the intermediate material 44 and the remolded object 43 did not break, but broke at a location other than the joint.

[0070] 18(a)-18(b) and 19(a)-19(b) show a method of producing the body 5 from a composite material 45. As shown in FIG. By cutting the composite material 45 as shown by the broken line in FIG. 18(a), the body 5 shown in FIG. 18(b) can be produced. The body 5 shown in FIG. 18(b) is used in the diaphragm valve 1B shown in FIG. 12. In the body 5, the end 35b where the rib 31 is formed is made of the remolded material 43 in the composite material 45, that is, made of cross-linked PFA with low dust generation. Also, the base 35a where the inlet 12 and the outlet 14 of the body 5 are formed is made of the intermediate material 44 in the composite material 45, that is, made of non-cross-linked fluororesin which is cheaper than cross-linked PFA. The inlet flow path 13 and the outlet flow path 15 are cut out from the intermediate material 44 so as to extend from the inlet 12 and the outlet 14 to the valve chamber 11. On the other hand, the rib 31 is cut out from the end 35b. Therefore, even if the contact portion 39 comes into contact with the valve seat portion 5a when the valve is opened or closed, the generation of particles can be suppressed, and contamination of the liquid in the valve chamber 11 due to the generated particles can be reduced.

[0071] 18(a) and 18(b), the inlet 12 to the inlet flow path 13, the valve chamber 11, the outlet flow path 15 to the outlet 14 are cut out from the base 35a, while only the valve seat 5a is cut out from the end 35b. Therefore, compared to the case where cutting is performed by the method shown in Fig. 19(a) and 19(b), the generation of particles is suppressed and the body 5 can be manufactured at low cost. 20(a) and 20(b), after forming a remolded product 43 in a cavity 44a of an intermediate material 44, another intermediate material 48 can be formed using another non-crosslinked fluororesin. Even in this case, the body 5 can be manufactured at low cost while suppressing particle generation, as compared to the case of cutting by the method shown in Fig. 19(a) and 19(b). Furthermore, as shown in Figures 22(a) and 22(b), only the ribs 31 can be made from cross-linked PFA, and the other parts can be made from non-cross-linked fluororesin. When only the ribs 31 are made from cross-linked PFA as shown in Figures 22(a) and 22(b), the size of the remolded object 43 in the composite material 45 can be kept particularly small. This makes it possible to obtain a diaphragm with excellent performance while reducing the amount of cross-linked PFA used, which is more expensive than non-cross-linked fluororesin.

[0072] Furthermore, as shown in FIG. 21(a) to FIG. 21(b), cavities 44a are provided in three locations in the intermediate material 44, corresponding to the inlet 12, the valve seat portion 5a, and the outlet 14, and the remolded product 43 and the other remolded product 49 made of cross-linked PFA can be formed in each of the three cavities 44a. Then, the valve seat portion 5a can be cut out from the remolded product 43, and the joint portion of the inlet 12 and the joint portion of the outlet 14 can be cut out from the other remolded product 49. In this case, dust generation (particle generation) caused by the contact and separation between the abutment portion 39 and the valve seat portion 5a can be suppressed, while dust generation (particle generation) from the joint portion to which the tubes of the inlet 12 and the outlet 14 are connected can also be suppressed. On the other hand, such a body 5 with low dust generation can be manufactured at low cost.

[0073] Next, the action and effect of the diaphragm valve 1B having the above configuration will be described. As shown in FIG. 12, in normal times when the working fluid is not supplied from the working fluid supply port 27 to the drive unit 7, the piston 21 of the drive unit 7 is urged downward by the coil spring 22 and pushed down. As a result, the valve body portion 3a moves in a direction approaching the valve seat portion 5a via the stem 19 and is pressed against the rib 31 of the valve seat portion 5a, and the diaphragm valve 1B is in a closed state (see FIG. 15(a)). Accordingly, the membrane portion 3b supporting the valve body portion 3a also deforms in a direction away from the drive unit 7. When the 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 that has flowed into the lower space S2 of the cylinder portion acts upward on the piston body 21a, and the piston 21 is pushed up against the urging force of the coil spring 22. At this time, the air in the upper space S1 is discharged to the outside from the ventilation port 26. As a result, the valve body 3a is moved away from the valve seat 5a via the stem 19, and the diaphragm valve 1B is opened (see FIG. 15(b)). Accordingly, the membrane portion 3b is also deformed in a direction approaching the drive portion 7. When the supply of working fluid to the working fluid supply port 27 is stopped, the piston 21 is again urged downward by the coil spring 22 and pushed down, and the valve body 3a is pressed against the rib 31 of the valve seat 5a, and the valve is closed again.

[0074] As described above, according to the diaphragm valve 1B of this embodiment, the valve seat portion 5a is provided with a rib 31 protruding toward the valve body portion 3a, and the rib 31 is made of cross-linked PFA from its tip to its base, and when the tertiary carbon concentration at the tip is M1 (mol%) and the tertiary carbon concentration at the base is 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 cross-linked PFA that is uniformly cross-linked from its tip to its base, so that the wear resistance and strength of the rib 31 are improved. Therefore, when the valve body portion 3a abuts against the rib 31 of the valve seat portion 5a when the valve is closed, the rib 31 is prevented from deforming and rubbing against the valve body portion 3a, and the amount of particles generated can be reduced. [Industrial Applicability]

[0075] The present invention can be widely used as a diaphragm valve having a diaphragm used for fluid control and a manufacturing method thereof. [Explanation of symbols]

[0076] 1A, 1B; diaphragm valve, 3; diaphragm, 3a; Valve body part, 3b; Membrane part, 3c; Outer periphery part, 5; body, 5a; valve seat, 7; Drive unit, 11; Valve chamber, 12; inlet; 13; inlet passage; 14; outlet; 15; outlet passage; 17; Drive unit housing, 18; Cover member, 19; stem, 19a; locking portion, 21; piston; 21a; piston body; 21b; guide shaft; 26; vent, 27; working fluid supply port, 31; Rib, 33a; base; 33b; end; 35a; base; 35b; end; 37; connecting hole, 37a; small diameter hole portion, 37b; large diameter hole portion, 39;Abutment part, 41; Cross-linked PFA film, 42; Cut pieces of cross-linked PFA film, 43; remolding; 44; intermediate material, 44a; cavity, 45; composite materials, 46;Mold, 48; Other intermediate materials, 49; Other reshaped products, C; moving axis, S1; Upper space, S2; Lower space.

Claims

1. A diaphragm valve comprising a diaphragm having a valve body and a membrane portion extending outward from the valve body and deformable in the direction of the movement axis, and a body having a valve seat portion to which the valve body, which reciprocates in the direction of the movement axis due to the deformation of the membrane portion, contacts and separates, Either the valve body or the valve seat is provided with a rib that protrudes toward the other. The aforementioned rib is made of bridged PFA from its tip to its base. The tertiary carbon concentration at the tip is M １ (Assuming mol%), the tertiary carbon concentration at the base is M ２ (When expressed as mol%), M １ ≥0.01, M ２ ≥ 0.01, and 0.8 ≤ M １ / M ２ Satisfying ≤ 1.2, Either the diaphragm or the body, the component having the ribs, A base made of non-crosslinked fluororesin, A diaphragm valve characterized by having an end portion which is integrated with the base portion and is provided with the ribs and is made of the bridging PFA.

2. The diaphragm valve according to claim 1, wherein the distance between the tip and the base of the rib is 250 μm or more.

3. The other component of either the valve body or the valve seat has a contact portion that contacts the rib provided on the other component, The diaphragm valve according to claim 1, wherein the contact portion is made of cross-linked fluororesin.

4. The diaphragm valve according to claim 1, wherein the rib is made of a remolded product of a crosslinked PFA film crosslinked to have a tertiary carbon concentration of 0.01 mol% or more.

5. The diaphragm valve according to claim 1, wherein one of the aforementioned parts is cut from a composite material which integrates an intermediate material made of a non-crosslinked fluororesin that forms the base, and a remolded product of a crosslinked PFA film crosslinked to have a tertiary carbon concentration of 0.01 mol% or more.

6. A method for manufacturing a diaphragm valve according to any one of claims 1 to 5, A cutting process to obtain cut pieces of a crosslinked PFA film that has been crosslinked so that the tertiary carbon concentration is 0.01 mol% or more, A reshaping step to reshape the aforementioned cut pieces to obtain a reshaped product, A method for manufacturing a diaphragm valve, comprising a forming step of obtaining the ribs from the remolded product.

7. A method for manufacturing a diaphragm valve according to claim 6, comprising an integration step to obtain a composite material by integrating an intermediate material made of a non-crosslinked fluororesin and the remolded product.

8. The integration process includes a piece-filling step of filling the piece in a cavity provided in the intermediate material, A method for manufacturing a diaphragm valve according to claim 7, comprising a firing step of melting the cut fragments in the cavity to obtain the remolded product and integrating the intermediate material and the remolded product.

9. The method for manufacturing a diaphragm valve according to claim 7, wherein the integration step includes an injection step of injecting molten material of the cut fragments into a cavity provided in the intermediate material to obtain a remolded product within the cavity and to integrate the intermediate material and the remolded product.

10. The integration process includes a piece-filling step of filling the piece in a cavity provided in the intermediate material, A method for manufacturing a diaphragm valve according to claim 7, comprising a compression molding step of compressing the cut pieces in the cavity to obtain the remolded product and integrating the intermediate material and the remolded product.

11. A method for manufacturing a diaphragm valve according to claim 6, comprising a welding step to obtain a composite material by welding together an intermediate material made of a non-crosslinked fluororesin and the previously obtained remolded product.

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