Needle valve and manufacturing method thereof

Abstract

In order to provide a needle valve and a manufacturing method for suppressing the generation of particles, a needle valve (1) is provided with: a diaphragm (3) having a needle part (3a) and a deformable membrane part (3b) that extends outward of the needle part (3a); and a main body (5) in which a valve chamber (6) is formed and which has a cylindrical flow path section (5a) that opens into the valve chamber, the opening area of the flow path section being adjustable by the reciprocating movement of the needle section in the direction of the movement axis (C), each of the needle section and the flow path section being configured from crosslinked PFA from one end to the other end, and each of the needle section and the flow path section being configured from crosslinked PFA from the other end to the other end. The tertiary carbon concentration M1 (mol%) at one end and the tertiary carbon concentration M2 (mol%) at the other end in each axial direction satisfy M1 > = 0.01, M2 > = 0.01, and 0.8 < = M1 / M2 < = 1.2. The production method comprises: a step for obtaining a cut sheet of a crosslinked PFA film which is crosslinked 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 the needle part and the flow path part from the reformed object.

Description

Technical Field

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

[0002] Needle 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 needle valve features a body and diaphragm made of fluoropolymers such as polytetrafluoroethylene (PTFE) and perfluoroalkoxyalkylene (PFA) to ensure excellent chemical resistance and flexural durability. The body has valve chambers communicating with multiple flow paths, and the diaphragm can reciprocate within the valve chamber in the direction of its moving axis. Therefore, the mechanism by which the gap between the needle portion located at the lower end of the diaphragm and the flow path portion changes achieves a variation in flow rate.

[0003] In such needle valves, it is necessary to prevent the generation of particles that occur during contact between the needle and the flow path. These particles can be defined as particles obtained by miniaturizing the material constituting the needle valve. While the needle and flow path are not necessarily designed to contact each other, they are designed to minimize the gap between them for flow control purposes. Therefore, the smaller the gap, the higher the probability of contact due to assembly deviations, dimensional tolerances of components, etc. Furthermore, since the needle and flow path are located in the liquid-contacting area, particles generated in these areas may become mixed into the flowing liquid. In the case of a cleaning solution used in semiconductor manufacturing, for example, the presence of particles in the cleaning solution can lead to reduced 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. 2022-095226 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Patent Document 1 discloses a flow control valve designed to suppress wear even when the needle valve core is in contact with the annular valve seat on one side. This flow control valve has an annular elastic body on the outer circumferential surface of a rod linked to the needle valve core, thus providing the rod with a degree of freedom to tilt about the elastic body. With this configuration, when the needle valve core is in contact with the annular valve seat on one side, the rod tilts, easing the contact pressure applied to the needle valve core and suppressing wear. However, the degree of freedom cannot be increased indefinitely. Furthermore, the temperature of the liquid can sometimes reach high temperatures of around 200°C. Considering the dimensional changes such as expansion / contraction that occur with temperature variations, it cannot be assumed that sufficient wear resistance can be achieved solely through the degree of freedom. In addition, Patent Document 1 describes using fluoropolymers (e.g., PFA or PTFE) as the material for the needle valve core and the annular valve seat (

[0040] ,

[0024] ), but neither describes nor suggests using cross-linked fluoropolymers as the material for the needle valve core and the annular valve seat.

[0009] The present invention was made in view of the above-mentioned actual situation, and its purpose is to provide a needle valve that can suppress the generation of particles and a method for manufacturing the same.

[0010] Technical solution

[0011] That is, the present invention includes the following contents.

[0012] [1] A needle valve comprising: a diaphragm having a needle portion and a membrane portion extending outward from the needle portion and deformable in a direction of a moving axis; and a body having a valve chamber and having a cylindrical flow path portion opening into the valve chamber, the axis of the flow path portion being aligned with the axis of the needle portion, and the opening area of ​​the flow path portion being adjustable by reciprocating movement of the needle portion in the direction of the moving axis caused by deformation of the membrane portion, characterized in that...

[0013] For each of the needle portion and the flow path portion, from one end to the other, it is composed of cross-linked perfluoroalkoxyalkane (PFA), and when the tertiary carbon concentration at one end in each axial direction is set as M1 (mol%) and the tertiary carbon concentration at the other end in each axial direction is set as M2 (mol%), M1 ≥ 0.01, M2 ≥ 0.01 and 0.8 ≤ M1 / M2 ≤ 1.2.

[0014] [2] According to the needle valve described in [1] above, wherein,

[0015] The diaphragm has: a base composed of a non-crosslinked fluoropolymer; and...

[0016] The end portion is integrated with the base portion, and the end portion has the needle portion and is composed of the cross-linked PFA.

[0017] [3] According to the needle valve described in [1] or [2] above, wherein,

[0018] The main body has: a base, composed of a non-crosslinked fluoropolymer; and

[0019] The end portion is integrated with the base portion, and the end portion has the flow path portion and is composed of the cross-linked PFA.

[0020] [4] The needle valve according to any one of [1] to [3] above, wherein,

[0021] The distance between one end and the other end is greater than or equal to 250 μm.

[0022] [5] The needle valve according to any one of [1] to [4] above, wherein,

[0023] The needle portion and the flow path portion are composed of a reshaped piece of a cross-linked PFA film, which is cross-linked in such a manner that the tertiary carbon concentration is greater than or equal to 0.01 mol%.

[0024] [6] According to the needle valve described in [2] above, wherein,

[0025] The diaphragm and the body are cut from a composite, which is an integrally formed of a cut piece of a cross-linked PFA membrane, which will become the base and is made of a non-cross-linked fluoropolymer intermediate, and cross-linked with a tertiary carbon concentration of ≥0.01 mol%.

[0026] [7] A method for manufacturing a needle valve, the method being a method for manufacturing a needle valve according to any one of [1] to [6] above, characterized in that it comprises:

[0027] 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%.

[0028] The reshaping process reshapes the cut pieces to obtain a reshaped article; and

[0029] The forming process involves obtaining the needle portion and the flow path portion from the remolded material.

[0030] [8] According to the manufacturing method of the needle valve described in [7] above, wherein,

[0031] The manufacturing method of the needle 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.

[0032] [9] According to the manufacturing method of the needle valve described in [8] above, wherein,

[0033] 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

[0034] 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.

[0035]

[10] According to the manufacturing method of the needle valve described in [8] or [9] above, wherein,

[0036] 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.

[0037]

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

[10] above, wherein,

[0038] 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

[0039] 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.

[0040]

[12] According to the manufacturing method of the needle valve described in [7] above, wherein,

[0041] The method for manufacturing the needle 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.

[0042] Invention Effects

[0043] The needle valve according to the present invention can suppress the generation of particles.

[0044] In a needle valve where the tertiary carbon concentration M1 (mol%) at one end of each axial direction and the tertiary carbon concentration M2 (mol%) at the other end of each axial direction are M1≥0.01 and M2≥0.01 respectively, and 0.8≤M1 / M2≤1.2, the needle portion and the flow path portion are formed from one end to the other in the axial direction by fully cross-linked PFA, thus suppressing particle generation from these locations. Therefore, compared to needle valves that do not satisfy the above-mentioned M1 and M2 relationships, the needle valve of the present invention can suppress particle generation.

[0045] In the aforementioned needle valve, the diaphragm may have: a base made of a non-crosslinked fluoropolymer; and an end portion integral with respect to the base portion, the end portion having a needle portion and being 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 portion, thus particularly enabling the flexural durability of the membrane portion of the diaphragm to be excellent. Furthermore, since it is not necessary to form the entire diaphragm from crosslinked PFA, the manufacturing cost of the needle valve can be reduced.

[0046] In the needle valve described above, the main body may have: a base made of non-crosslinked fluoropolymer; and an end portion integral with respect to the base portion, the end portion having a flow path portion and being 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 portion, thus particularly enabling excellent flexural durability of the membrane portion of the diaphragm. Furthermore, since it is not necessary to form the main body integrally from crosslinked PFA, the manufacturing cost of the needle valve can be reduced.

[0047] In the needle valve described above, the distance between one end and the other end can be greater than or equal to 250 μm. Normally, it is difficult to crosslink a thick layer of non-crosslinked PFA throughout its entire surface and back, from the viewpoint of radiation transmittance, but this can be achieved through the needle valve manufacturing method described later. Furthermore, by having a needle portion and flow path portion with a distance greater than or equal to 250 μm, wear on the needle portion and flow path portion can be suppressed compared to cases where the distance is less than 250 μm, thus enabling more accurate flow control over a longer period.

[0048] In the aforementioned needle valve, the needle portion and flow path portion can be constructed from a remolded piece of a cross-linked PFA film, which is cross-linked to a tertiary carbon concentration of ≥0.01 mol%. That is, it is difficult from the viewpoint of radiation transmittance to cross-link a thick, non-cross-linked PFA film entirely across its surface and back to a tertiary carbon concentration of ≥0.01 mol%, but by irradiating a non-cross-linked PFA film of sufficient thickness to achieve this cross-linking, a cross-linked PFA film with a tertiary carbon concentration of ≥0.01 mol% can be obtained entirely across its surface and back. If a component is constructed from cross-linked PFA obtained by remolding a piece of this cross-linked PFA film, regardless of its thickness, a cross-linked PFA component with uniform cross-linking can be manufactured. By forming the needle portion and flow path portion from such a cross-linked PFA component with uniform cross-linking throughout, the generation of particles accompanying contact between the needle portion and the flow path portion can be significantly suppressed.

[0049] In the aforementioned needle valve, the diaphragm and body can be manufactured by cutting a composite component, which is an integrally formed piece of a cut sheet of a cross-linked PFA membrane, which serves as the base and is made of a non-crosslinked fluoropolymer resin. This cross-links the membrane to a concentration of tertiary carbon greater than or equal to 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 enhancing the flexural durability of the membrane portion of the diaphragm. Furthermore, since the diaphragm or body is not integrally formed from crosslinked PFA, the manufacturing cost of the needle valve can be reduced.

[0050] According to the needle valve manufacturing method of the present invention, a method for manufacturing a needle valve capable of suppressing particle generation can be provided.

[0051] That is, by including 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 forming process for obtaining needles and flow paths from the remolded product, a cross-linked PFA film with a tertiary carbon 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) can be obtained, whose entire structure is composed of cross-linked PFA with a tertiary carbon concentration of ≥0.01 mol%. By forming the needles and flow paths from such a cross-linked PFA member with a uniform degree of cross-linking, particle generation accompanying contact between the needles and flow paths can be significantly suppressed.

[0052] In the above-described needle valve manufacturing method, an integration process can be included to obtain a composite part formed by integrating an intermediate component made of non-crosslinked fluoropolymer and a remolded part. In this case, a non-crosslinked fluoropolymer with superior flexural durability compared to crosslinked PFA can be used, thus the membrane portion of the diaphragm can be formed in the intermediate component portion of the composite part, thereby achieving excellent flexural durability of the membrane portion. Furthermore, it is not necessary to form the diaphragm or the main body integrally from crosslinked PFA, thus reducing the manufacturing cost of the needle valve. In the above-described needle valve manufacturing method, the integration process may include: a cut-piece receiving process, in which a cut-piece is received in a cavity provided in the intermediate component; and a firing process, in which the cut-piece is melted in the cavity to obtain a remolded part, and the intermediate component and the remolded part are integrated. In addition, in the above-described needle valve manufacturing method, the integration process may include: an injection molding process, in which molten material of the cut-piece is injected into the cavity provided in the intermediate component, a remolded part is obtained in the cavity, and the intermediate component and the remolded part are integrated. Furthermore, in the above-described needle valve manufacturing method, 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 remolded part, and the intermediate part and the remolded part are integrated. Furthermore, in the above-described needle valve manufacturing method, 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 remolded part, and the intermediate part and the remolded part are integrated. Furthermore, in the above-described needle valve manufacturing method, a welding process may be included to obtain a composite part formed by welding an intermediate part made of non-crosslinked fluororesin to a pre-obtained remolded part. By including these processes, a composite part formed by integrating an intermediate part made of non-crosslinked fluororesin with a remolded part can be obtained. Therefore, as described above, a diaphragm that has a needle portion and a flow path portion integrally formed of uniformly crosslinked PFA can be obtained, while also having a membrane portion with excellent bending durability. Furthermore, there is no need to form a diaphragm or main body from cross-linked PFA, thus reducing the manufacturing cost of needle valves. Attached Figure Description

[0053] The invention will be further described in the following detailed description with reference to the numerous accompanying drawings, which are non-limiting examples of typical embodiments of the invention, though in some of the drawings the same reference numerals denote the same parts.

[0054] Figure 1 This is a longitudinal sectional view of the needle valve in the embodiment.

[0055] Figure 2 This is a longitudinal sectional view of the diaphragm that makes up the needle valve.

[0056] Figure 3 This is a longitudinal sectional view of the main body that makes up the needle valve.

[0057] Figure 4 This is a diagram illustrating the function of a needle valve. Figure 4 (a) represents the fully closed state. Figure 4 (b) indicates the fully open state.

[0058] Figure 5 This is an explanatory diagram illustrating the manufacturing process of a needle 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.

[0059] Figure 6 This is an explanatory diagram illustrating the manufacturing method of a needle valve (an 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 receiving section of the intermediate part.

[0060] Figure 7 This is an explanatory diagram illustrating the manufacturing method of a needle valve (the process of forming the needle). 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.

[0061] Figure 8 This is an explanatory diagram illustrating the manufacturing method (needle formation process) of other types of needle 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.

[0062] Figure 9 This is an explanatory diagram illustrating a different method of manufacturing a needle valve (the needle formation process). 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.

[0063] Figure 10 This is an explanatory diagram illustrating the manufacturing method of a needle valve (an integrated process of intermediate parts and remolded parts). Figure 10 (a) represents a three-dimensional view of the intermediate part and the reshaped part. Figure 10 (b) shows a longitudinal sectional view of the case where the reshaped part is contained in the receiving section of the intermediate part.

[0064] Figure 11This is an explanatory diagram illustrating the manufacturing method of a needle valve (the process of forming the flow path). Figure 11 (a) represents a longitudinal sectional view of the composite component. Figure 11 (b) represents a longitudinal sectional view of the main body obtained by cutting the composite.

[0065] Figure 12 This is an explanatory diagram used to illustrate the manufacturing method of needle valves in other ways (the integrated process of intermediate parts and remolded parts). Detailed Implementation

[0066] 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.

[0067] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0068] like Figure 1 As shown, the needle valve 1 of this embodiment includes: a diaphragm 3 having a needle portion 3a and a membrane portion 3b extending outward from the needle portion 3a and deformable in the direction of the moving axis C; and a body 5 having a valve chamber 6 and a cylindrical flow path portion 5a with an opening in the valve chamber 6. Furthermore, the axis of the flow path portion 5a of the needle valve 1 is aligned with the axis of the needle portion 3a, and the opening area of ​​the flow path portion 5a can be adjusted by the reciprocating movement of the needle portion 3a in the direction of the moving axis C caused by the deformation of the membrane portion 3b. Moreover, the needle valve 1 includes a drive unit 15 for driving the diaphragm 3.

[0069] The diaphragm 3 is configured to block the opening above the valve chamber 6 and is fixed to the main body 5. Furthermore, the diaphragm 3 has: a needle portion 3a located in the center; an annular membrane portion 3b formed with a thin wall to facilitate bending and support the needle portion 3a; and an outer peripheral portion 3c located on the outer periphery of the membrane portion 3b (see reference). Figure 2 Furthermore, the diaphragm 3 has a valve core portion 3d arranged to surround the needle portion 3a. Also, the diaphragm 3 has a connecting portion 3e located on the upper part of the needle portion 3a and connected to the valve stem 16 of the drive unit 15. Furthermore, the diaphragm 3, while supporting the needle portion 3a and the valve core portion 3d within the valve chamber 11 via the membrane portion 3b, divides the space between the valve chamber 6 and the drive unit 15.

[0070] Furthermore, the needle portion 3a protrudes beyond the top of the valve core portion 3d (specifically, the top of the rib 4) and toward the flow path portion 5a. The needle portion 3a also has a tapered shape that tapers towards the flow path portion 5a. Moreover, the shape of the flow path portion 5a (the flow path defined by the inner circumference of the flow path portion 5a) in a cross-section orthogonal to the axial direction corresponds to the shape of the needle portion 3a in that cross-section (e.g., both are circular). Furthermore, each part is formed and assembled such that the center of the flow path portion 5a in that cross-section approximately coincides with the center of the needle portion 3a in that cross-section. Therefore, by adjusting the insertion position of the needle portion 3a relative to the flow path portion 5a, the size of the flow path defined by the inner circumferential surface of the flow path portion 5a and the outer circumferential surface of the needle portion 3a is adjusted, thereby regulating the flow rate of the flow path portion 5a.

[0071] Furthermore, the diaphragm portion 3b is configured to extend radially outward from the needle portion 3a. More specifically, it is formed to extend radially outward from the outer periphery of the lower end of the connecting portion 3e. Furthermore, the outer periphery of the diaphragm portion 3b has a generally circular shape. Furthermore, the outer peripheral edge portion 3c has an L-shaped cross-section. Furthermore, at least a portion of the outer peripheral edge portion 3c is sandwiched between the main body 5 and the pressing member 21. Furthermore, an annular rib 4 protruding towards the flow path portion 5a is provided in the valve core portion 3d. The rib 4 presses against the valve seat surface 5b, thereby making the flow path of the flow path portion 5a fully closed. Furthermore, threaded portions 26 that engage with each other are formed on the outer peripheral surface of the connecting portion 3e and the inner peripheral surface of the lower end of the valve stem 16, respectively. Moreover, the diaphragm 3 and the valve stem 16 are connected via the connecting portion 3e, and the diaphragm 3 is raised and lowered via the valve stem 16 by the drive portion 15, thereby adjusting the insertion position of the needle portion 3a relative to the flow path portion 5a.

[0072] It should be noted that, in this embodiment, the diaphragm 3 is shown as having a valve core portion 3d, but it is not limited to this; it may also be used without the valve core portion 3d (see [reference]). Figure 9 In this case, for example, a stop portion that engages with the valve stem 16 is provided on the drive housing 17 side, thereby restricting the descent position of the needle portion 3a of the diaphragm 3.

[0073] like Figure 2As 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, the end portion 33b having needle portions 3a and being 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 flexural durability than crosslinked PFA. Furthermore, the end portion 33b, including the needle portions 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 7-9 ).

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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). This is because the concentration of tertiary carbon calculated by formula (1) and the concentration of tertiary carbon calculated by formula (2) are usually substantially equivalent values.

[0078] 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.

[0079] [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 ].

[0080] [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 ].

[0081] [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 "IC / 6”, record this value as [I C / 6 ].

[0082] [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 "I D / 4”, record this value as [I D / 4 ].

[0083] [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 ].

[0084] [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 ].

[0085] [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 ].

[0086] [Calculation formula (1)] Based on I C / 6 tertiary carbon concentration

[0087] 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

[0088] [Calculation formula (2)] Based on I G / 1 tertiary carbon concentration

[0089] 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

[0090] [Table 1]

[0091]

[0092] The needle portion 3a is composed of cross-linked PFA from one end to the other. With the tertiary carbon concentration at one end set as M1 (mol%) and the tertiary carbon concentration at the other end 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 one end of the needle portion 3a exceeds 0.01 mol%, and the tertiary carbon concentration M2 at the other end 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, the needle portion 3a is formed from uniformly cross-linked PFA from one end to the other. In addition, the distance D1 between one end and the other end of the needle portion 3a is approximately 250 μm to 6000 μm (refer to...). Figure 2 The value is set to be greater than or equal to 250 μm. It should be noted that the needle portion 3a is the part of the end portion 33b that can be inserted into the flow path portion 5a and is formed into a tapered shape at a certain angle (see reference). Figure 2 ).

[0093] Such a needle portion 3a, composed of uniformly cross-linked PFA from one end to the other, can be formed arbitrarily, but it can be formed from a reshaped piece 43 of a cross-linked PFA film 41 cross-linked in such a manner that the tertiary carbon concentration is greater than or equal to 0.01 mol% (see reference). Figure 5 ).

[0094] 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 43 can also be obtained by reshaping the cut pieces 42 of the crosslinked PFA film 41.

[0095] In the main body 5, a valve chamber 6 is formed at the upper center, and a first flow path and a second flow path communicating with the valve chamber 6 are formed. Furthermore, in the main body 5, a flow path portion 5a facing the needle portion 3a is formed at the opening from the first flow path to the valve chamber 6. Additionally, the upper end face of the flow path portion 5a of the main body 5 forms a valve seat surface 5b for the rib 4 of the valve core portion 3d to abut / separate from (see reference). Figure 2 and Figure 3 In this embodiment, as a first flow path, an inlet flow path 8 is formed, extending from an inlet 7 formed on one of the opposing sides of the main body 5 and opening at the center of the bottom of the valve chamber 6. A valve seat surface 5b is formed around the opening from the inlet flow path 8 to the valve chamber 6. Furthermore, as a second flow path, an outlet flow path 10 is formed, extending from an outlet 9 formed on the other opposing side of the main body 5 and opening at the outer side of the bottom of the valve chamber 6. The outlet flow path 10 is formed to open at the outer side of the bottom of the valve chamber 6 and to be at the same height as the inlet flow path 8.

[0096] A recess 12 is provided on the upper part of the main body 5 to accommodate the fitting portion 21b of the pressing member 21. Furthermore, a drive housing 17 is disposed above the main body 5, and a base plate 13 is disposed below the main body 5. The drive housing 17 has a hollow cylindrical shape, and the base plate 13 has a flange shape. The drive housing 17, the main body 5, and the base plate 13 are fastened together by bolts and nuts (not shown). The main body 5 is clamped and fixed between the drive housing 17 and the base plate 13.

[0097] 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, the end portion 35b having a flow path portion 5a and being 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 less expensive than crosslinked PFA. Furthermore, the end portion 35b, including the flow path portion 5a, 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 integrally formed from an intermediate 44 (which will become the base 35a) made of non-crosslinked fluoropolymer, and a reshaped piece 43 (i.e., the reshaped piece 43 that becomes 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). Figure 5 , Figure 10 as well as Figure 11 ).

[0098] The type of fluoropolymer used to form the aforementioned non-crosslinked fluoropolymer is not limited. As previously described in the description of membrane 3, polymers (homopolymers or copolymers) using fluorinated polymerizable compounds such as tetrafluoroethylene, hexafluoropropylene, difluoroethylene, trifluorochloroethylene, and perfluoroalkoxyethylene (perfluoromethoxyethylene, perfluoroethoxyethylene, etc.) as monomers can be used. Among these, ethylene (unfluorinated ethylene) can be used as the monomer for the copolymer. Specifically, PTFE, PFA, FEP, ETFE, PVDF, PCTFE, ECTFE, etc., can be used, for example. 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 viewpoints of reducing material costs.

[0099] Furthermore, the crosslinking in the fluoropolymer is also as previously described in the description of diaphragm 3.

[0100] Regarding the flow path 5a, when the tertiary carbon concentration at one end in the axial direction is set to M1 (mol%) and the tertiary carbon concentration at the other end in the axial direction is set to M2 (mol%), the following conditions are met: M1 > 0.01, M2 > 0.01, and 0.8 ≤ M1 / M2 ≤ 1.2. Therefore, the flow path 5a is formed of cross-linked PFA uniformly cross-linked throughout the axial direction, exhibiting high wear resistance and strength. Furthermore, the flow path 5a is formed from a reshaped piece 43 of a cross-linked PFA film cut from a cross-linked film with a tertiary carbon concentration greater than or equal to 0.01 mol%. The distance D2 between one end and the other end of the flow path 5a is approximately 250 μm to 6000 μm (refer to...). Figure 2 The thickness D3 of the flow path section 5a is set to be greater than or equal to 250 μm. Furthermore, the thickness D3 is also approximately 250 μm to 12000 μm (refer to...). Figure 2), set to greater than or equal to 250μm.

[0101] Such a flow path section 5a, composed of cross-linked PFA uniformly cross-linked from one end to the other, can be formed arbitrarily, but it can be formed from a reshaped piece 43 of a cross-linked PFA film 41 cross-linked in such a way that the tertiary carbon concentration is greater than or equal to 0.01 mol% (see reference). Figure 5 ).

[0102] 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 43 can also be obtained from the cut piece 42 of the crosslinked PFA film 41 by reshaping.

[0103] Furthermore, the aforementioned drive unit 15 allows the diaphragm 3 and valve stem 16 to move axially forward and backward together via manual operation, thereby adjusting the position of the needle portion 3a relative to the flow path portion 5a. The drive unit 15 moves the valve stem 16 using a threaded engagement mechanism. Specifically, the drive unit 15 consists of a threaded portion 27 and a threaded portion 28. The threaded portion 27 is configured to engage with the inner circumferential surface of the through hole 24 of the drive unit housing 17 and the outer circumferential surface of the first valve stem 16a, respectively. The threaded portion 28 is configured to engage with the inner circumferential surface of the first valve stem 16a and the outer circumferential surface of the second valve stem 16b, respectively. However, the drive unit 15 is not limited to a manually operated threaded mechanism; for example, it can also be driven by fluid pressure (air pressure, etc.) or by an electric actuator equipped with a motor, solenoid, etc.

[0104] The valve stem 16 is connected to the connecting portion 3e of the diaphragm 3 and extends toward the side opposite to the flow path portion 5a. The valve stem 16 has a first valve stem 16a and a second valve stem 16b connected to the first valve stem 16a via a threaded portion 28. The connecting portion 3e of the diaphragm 3 is connected to the lower end of the second valve stem 16b via a threaded portion 26. The first valve stem 16a is made of PVDF. The first valve stem 16a has a hollow cylindrical shape with an opening at the lower end. Furthermore, a stop portion 18 extending radially outward is provided at the lower end of the first valve stem 16a. Furthermore, a handle 19 for rotating the first valve stem 16a is fitted to the upper end of the first valve stem 16a. Furthermore, the second valve stem 16b is made of PVDF. Furthermore, the lower outer periphery of the second valve stem 16b is formed into a hexagonal shape.

[0105] The drive housing 17 is made of PVDF. Furthermore, a through hole 24 for inserting the first valve stem 16a is formed at the upper end of the drive housing 17. Additionally, a stepped portion 17a with a hexagonal inner circumferential surface is provided at the lower part of the drive housing 17. The pressing member 21 is also made of PVDF. The pressing member 21 has a stepped portion 21a and a cylindrical fitting portion 21b located on the lower outer circumference of the stepped portion 21a. Both the stepped portion 21a and the fitting portion 21b have hexagonal outer circumferences. A through hole 22 with a hexagonal inner circumferential surface is formed at the center of the pressing member 21. The lower part of the second valve stem 16b is inserted into the through hole 22 in a non-rotatable manner. Furthermore, the stepped portion 21a of the pressing member 21 is fitted into the stepped portion 17a of the drive housing 17 in a non-rotatable manner. Furthermore, the fitting portion 21b of the pressing member 21 is fitted into the recess 12 of the main body 5 in a non-rotatable manner. Thus, the pressing member 21 supports the second valve stem 16b so that it can move freely up and down without rotating.

[0106] Next, the manufacturing method of the needle valve 1 with the above configuration will be described.

[0107] 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.

[0108] In this embodiment, the fabrication is as follows Figure 6 (Manufacturing of diaphragm 3) and Figure 10(Manufacturing of Body 5) The cup-shaped intermediate part 44 shown has a recess at its upper end that functions as a cavity 44a. The intermediate part 44 can be formed by any method, for example, by machining the recess at the upper end of a rod-shaped body or plate that is compressed from non-crosslinked fluoropolymer using a free baking method, hot molding method, or the like using a mold. Similarly, it can also be manufactured by compressing a cup-shaped rod-shaped body or plate with a recess at its upper end using a non-crosslinked fluoropolymer using a free baking method, hot molding method, or the like using a mold.

[0109] 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.

[0110] On the other hand, products made from cross-linked PFA, such as Figure 6 and Figure 10 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.

[0111] 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 5As 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.

[0112] 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 5 As 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.

[0113] On the other hand, if the reshaped material 43 is reshaped inside cavity 44a, such as Figure 12 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.

[0114] 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).

[0115] 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 needle 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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 1 The diaphragm used in the needle valve 1 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.

[0122] 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 remolded 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 under impact, no gap will form at the boundary between the base portion 33a and the end portion 33b, preventing liquid intrusion into the valve chamber 6 and thus preventing a decrease in strength. Furthermore, both the intermediate portion 44 and the remolded 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.

[0123] 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), the portion closer to the tip of membrane 3b 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 smaller, and the base portion 33a made of non-cross-linked fluoropolymer can be made larger. In this case, it is practically possible to make only the needle portion 3a made of cross-linked PFA, thereby obtaining a needle valve 1 that further suppresses costs and has low dust generation.

[0124] Next, the function of the needle valve 1 constructed as described above will be explained. In the fully closed state of needle valve 1 (refer to...), Figure 4 In (a) of the above conditions, the fluid flowing into the inlet flow path 8 is closed by pressing the rib 4 of the valve core 3d against the valve seat surface 5b. When the handle 19 is turned from the fully closed state to the opening direction, the first valve stem 16a rotates and rises. The rotation of the first valve stem 16a is transmitted to the second valve stem 16b, causing the second valve stem 16b to rise. The diaphragm 3 connected to the second valve stem 16b rises, and the rib 4 of the valve core 3d separates from the valve seat surface 5b. When the handle 19 is turned further to raise the diaphragm 3, the needle 3a rises and becomes half-open. At this time, a part of the needle 3a is inserted into the flow path 5b. The opening area obtained by subtracting the needle 3a from the flow path 5b becomes the area of ​​the passage. The flow rate of the flow path 5b is adjusted by adjusting the area of ​​this passage. When adjusting the flow rate, the handle 19 is operated to adjust the opening to achieve the desired flow rate. When the handle 19 is further rotated from the half-open state, the stop portion 18 of the first valve stem 16a presses against the top surface of the drive housing 17, causing the rotation of the first valve stem 16a to stop, and the needle valve 1 becomes fully open (see reference). Figure 4 (b)

[0125] As described above, when needle valve 1 is fully closed, the rib 4 of valve core 3d presses against valve seat surface 5b to achieve a full closure seal. If the opening is increased, diaphragm 3 rises, and needle 3a and valve core 3d rise to full opening along with diaphragm 3. Even when fully open, needle 3a will not detach from flow path 5b, allowing flow regulation from fully closed to fully open.

[0126] Industrial availability

[0127] This invention is widely used as a needle valve having a diaphragm for fluid control and a method for manufacturing the same.

[0128] Explanation of reference numerals in the attached figures

[0129] 1: Needle valve;

[0130] 3: Diaphragm;

[0131] 3a: Needle portion; 3b: Membrane portion; 3c: Peripheral portion;

[0132] 5: Main body; 5a: Flow path section; 5b: Valve seat surface;

[0133] 6: Valve chamber;

[0134] 7: Inlet / outlet;

[0135] 8: Inlet flow path;

[0136] 9: Outlet;

[0137] 10: Exit flow path;

[0138] 12: concave part;

[0139] 13: Base plate;

[0140] 15: Drive unit;

[0141] 16: Valve stem; 16a: First valve stem; 16b: Second valve stem;

[0142] 17: Drive unit housing; 17a: Stepped section;

[0143] 18: Stop part;

[0144] 19: Handle;

[0145] 21: Pressing component; 21a: Stepped portion; 21b: Fitting portion;

[0146] 22: Through hole;

[0147] 24: Through hole;

[0148] 26, 27, 28: Threaded section;

[0149] 33a: base; 33b: end;

[0150] 35a: base; 35b: end;

[0151] 41: Cross-linked PFA membrane;

[0152] 42: Cut pieces of cross-linked PFA membrane;

[0153] 43: Reshaped product;

[0154] 44: Middleware; 44a: Cavity;

[0155] 45: Composite parts;

[0156] 46: Mold;

[0157] C: Moving axis.

Claims

1. A needle valve comprising: a diaphragm having a needle portion and a membrane portion extending outward from the needle portion and deformable in a direction of a movement axis; and a body having a valve chamber and a cylindrical flow path portion having an opening in the valve chamber, the axis of the flow path portion being aligned with the axis of the needle portion, and the opening area of ​​the flow path portion being adjustable by reciprocating movement of the needle portion in the direction of the movement axis caused by deformation of the membrane portion, characterized in that... For each of the needle portion and the flow path portion, from one end to the other, it is composed of cross-linked perfluoroalkoxyalkane (PFA), where, with the tertiary carbon concentration at one end in each axial direction set as M1 and the tertiary carbon concentration at the other end in each axial direction set as M2, the following conditions are 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 needle valve according to claim 1, wherein, The diaphragm has: a base composed of a non-crosslinked fluoropolymer; and... The end portion is integrated with the base portion, and the end portion has the needle portion and is composed of the cross-linked PFA.

3. The needle valve according to claim 1, wherein, The main body has: a base, composed of a non-crosslinked fluoropolymer; and The end portion is integrated with the base portion, and the end portion has the flow path portion and is composed of the cross-linked PFA.

4. The needle valve according to claim 1, wherein, The distance between one end and the other end is greater than or equal to 250 μm.

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

6. The needle valve according to claim 2, wherein, The diaphragm and the body are cut from a composite, which is an integrally formed of a cut piece of a cross-linked PFA membrane, which will become the base and is made of a non-cross-linked fluoropolymer intermediate, and cross-linked with a tertiary carbon concentration of ≥0.01 mol%.

7. A method for manufacturing a needle valve, wherein the method for manufacturing a needle valve is according to claim 1, 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 needle portion and the flow path portion from the remolded material.

8. The method for manufacturing a needle valve according to claim 7, wherein, The manufacturing method of the needle 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 needle valve according to claim 8, wherein, The integrated process includes: The cut piece receiving process involves receiving the cut piece into a cavity provided in the intermediate member; 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 needle 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 needle 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 needle valve according to claim 7, wherein, The method for manufacturing the needle 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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