Constant pressure valve

Abstract

[Project] To provide a constant pressure valve capable of reducing particle generation while having excellent diaphragm flexibility. [Solution] A valve body side contact surface (21x) is formed on the valve body (21) and perpendicular to the direction of movement of the valve body (21) and the shaft (31), and a shaft side contact surface (31x) is formed on the shaft (31) and perpendicular to the direction of movement of the valve body (21) and the shaft (31), and a valve seat side contact surface (41x) is formed on the flow control path (13) and perpendicular to the direction of movement of the valve body (21) and the shaft (31), and a valve blocking contact portion (41y) protruding in a ring shape is formed on the valve body side contact surface (21x) or the valve seat side contact surface (41x), and a valve body pressing contact portion (31y) protruding in a ring shape is formed on the valve body side contact surface (21x) or the shaft side contact surface (31x), and the shaft (31) and the shaft side The diaphragm (32) is formed from a composite material formed by bonding PTFE and PFA, the shaft-side diaphragm (32) is formed from PTFE, and the shaft-side contact surface (31x) is formed from PFA.

Description

Technology Field

[0001] The present invention relates to a constant pressure valve that maintains a constant pressure on the outlet side caused by a controlled fluid flowing out from an outlet channel, even when the pressure on the inlet side caused by the controlled fluid flowing in from an inlet channel fluctuates. Background Technology

[0002] In the cleaning and stripping processes of silicon wafers for semiconductor device manufacturing, highly corrosive chemicals such as strong acids or strong alkalis are used.

[0003] In addition, metal or organic solutes from the valve are not allowed, and the chemical solution used in the cleaning and stripping process requires a very high degree of cleanliness. Therefore, fluorine resin, which is a low-leaching material with excellent acid and alkali resistance, is used for the valve that carries the chemical solution.

[0004] Since the mixing of particles into the fluid flow path during the semiconductor manufacturing process significantly affects product yield, the generation of particles from valves is not permitted.

[0005] For this reason, as a valve for supplying high-purity chemical solutions and ultrapure water, a structure is adopted in which the driving part and the liquid contact part are isolated by a diaphragm so that oscillations from the sliding part (contact part) do not affect the liquid contact part of the valve.

[0006] For example, Patent Document 1 proposes a constant pressure valve having an inlet path through which a controlled fluid is introduced, an outlet path through which a controlled fluid is discharged, a flow control path located between the inlet path and the outlet path, a valve body disposed in the flow control path, a valve body-side diaphragm that displaces the valve body, a shaft that pressurizes the valve body, and a shaft-side diaphragm that displaces the shaft, wherein an inlet path is connected to one side of the valve body-side diaphragm and a valve body-side pressurizing chamber is formed on the other side of the valve body-side diaphragm, and an outlet path is connected to one side of the shaft-side diaphragm and a shaft-side pressurizing chamber is formed on the other side of the shaft-side diaphragm. Prior art literature

[0007] Japanese Patent Publication No. JP 2000-193106 The problem to be solved

[0008] PTFE (tetrafluorinated ethylene resin) is a material with excellent chemical resistance and flexibility, and a long lifespan.

[0009] However, nowadays, with the development of higher miniaturization of semiconductor manufacturing processes (10 nm process or less), improvements are also required regarding oscillation from the machined surface, and it has become difficult to sufficiently meet these requirements even by using PTFE.

[0010] Therefore, the present invention aims to provide a constant pressure valve capable of reducing particle generation while having excellent flexibility of the diaphragm. means of solving the problem

[0011] The constant pressure valve of the present invention according to claim 1 comprises an inlet passage (11) into which a fluid to be controlled flows in, an outlet passage (12) into which the fluid to be controlled flows out, a flow rate control passage (13) located between the inlet passage (11) and the outlet passage (12), a valve body (21) disposed in the flow rate control passage (13), a valve body-side diaphragm (22) that displaces the valve body (21), a shaft (31) that pressurizes the valve body (21), and a shaft-side diaphragm (32) that displaces the shaft (31). The inlet passage (11) is connected to one side of the valve body-side diaphragm (22), and a valve body-side pressurizing chamber (14) is formed on the other side of the valve body-side diaphragm (22). The outlet passage (12) is connected to one side of the shaft-side diaphragm (32), and the shaft-side A shaft-side pressurized chamber (15) is formed on the other side of the diaphragm (32), and even if the inlet-side pressure of the fluid to be controlled flowing in from the inlet passage (11) fluctuates, the valve body-side diaphragm (22) and the shaft-side diaphragm (32) are deformed to maintain a constant outlet-side pressure of the fluid to be controlled flowing out from the outlet passage (12). In the valve body (21), a valve body-side contact surface (21x) is formed perpendicular to the direction of movement of the valve body (21) and the shaft (31), and in the shaft (31), a shaft-side contact surface (31x) is formed perpendicular to the direction of movement of the valve body (21) and the shaft (31). In the flow control passage (13), a valve seat-side contact surface (41x) is formed perpendicular to the direction of movement of the valve body (21) and the shaft (31). A valve closing contact portion (41y) protruding in a ring shape is formed on the valve body side contact surface (21x) or the valve seat side contact surface (41x), and a valve body pressing contact portion (31y) protruding in a ring shape is formed on the valve body side contact surface (21x) or the shaft side contact surface (31x).The shaft (31) and the shaft-side diaphragm (32) are formed from a composite material formed by bonding PTFE and PFA, the valve body (21) and the valve body-side diaphragm (22) are formed from the composite material, the shaft-side diaphragm (32) and the valve body-side diaphragm (22) are formed by the PTFE, the shaft-side contact surface (31x), the valve body-side contact surface (21x), the valve closing contact part (41y), and the valve body pressure contact part (31y) are formed by the PFA, and the valve body-side contact surface (21x) and the valve seat-side contact surface (41x) are brought into contact by the valve closing contact part (41y), and the valve body-side contact surface (21x) and the valve seat-side contact surface (41x) are brought into contact by the valve body pressure contact part (31y). It is characterized by bringing the shaft-side contact surface (31x) into contact.

[0012] delete

[0013] delete

[0014] delete

[0015] The present invention according to claim 5 is a constant pressure valve according to claim 1, wherein a body (40) is composed of a flow path forming body (41), a valve body side body (42), and a shaft side body (43); the flow path forming body (41) forms the inlet flow path (11), the outlet flow path (12), and the flow rate control flow path (13); the valve body side body (42) forms the valve body side pressurizing chamber (14); the shaft side body (43) forms the shaft side pressurizing chamber (15); the valve body side diaphragm (22) is fixed to the flow path forming body (41) by the valve body side body (42); the shaft side diaphragm (32) is fixed to the flow path forming body (41) by the shaft side body (43); and the valve body side body (42) and the shaft side body (43) are formed on the PTFE It is characterized by being formed by, and the above-mentioned body (41) for forming the Euro is formed by the above-mentioned PFA. Effects of the invention

[0016] According to the constant pressure valve of the present invention, the valve body-side contact surface, the shaft-side contact surface, and the valve seat-side contact surface are formed as surfaces perpendicular to the direction of movement of the valve body and the shaft, and the valve body-side contact surface and the valve seat-side contact surface are brought into contact by a ring-shaped protruding valve closing contact part, and the valve body-side contact surface and the shaft-side contact surface are brought into contact by a ring-shaped protruding valve body pressing contact part, thereby reducing the generation of particles caused by contact. Furthermore, by forming the shaft and the shaft-side diaphragm from a composite material, the generation of particles can be reduced compared to the case where the shaft and the shaft-side diaphragm are formed from other materials. Additionally, by forming the shaft-side diaphragm from PTFE, excellent flexibility is achieved, and by forming the shaft-side contact surface from PFA, the generation of particles can be reduced. Brief explanation of the drawing

[0017] FIG. 1 is a cross-sectional view illustrating a pressure regulating valve according to one embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating the operating state of the same pressure regulating valve. FIG. 3 is a cross-sectional view illustrating a pressure regulating valve according to another embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating a pressure regulating valve according to another embodiment of the present invention. Specific details for implementing the invention

[0018] A constant pressure valve according to the first embodiment of the present invention has a valve body-side contact surface formed perpendicular to the direction of movement of the valve body and the shaft, a shaft-side contact surface formed perpendicular to the direction of movement of the valve body and the shaft, a flow control path has a valve seat-side contact surface formed perpendicular to the direction of movement of the valve body and the shaft, a valve body-side contact surface protruding in a ring shape is formed on the valve body-side contact surface or the valve seat-side contact surface, a valve closing contact portion protruding in a ring shape is formed on the valve body-side contact surface or the shaft-side contact surface, a valve body pressing contact portion protruding in a ring shape is formed on the valve body-side contact surface or the shaft-side contact surface, the shaft and the shaft-side diaphragm are formed from a composite material formed by bonding PTFE and PFA, the shaft-side diaphragm is formed from PTFE, and the shaft-side contact surface is formed from PFA. According to the present embodiment, the valve body-side contact surface, the shaft-side contact surface, and the valve seat-side contact surface are formed as surfaces perpendicular to the direction of movement of the valve body and the shaft. Since the valve body-side contact surface and the valve seat-side contact surface are brought into contact by a ring-shaped protruding valve closing contact part, and the valve body-side contact surface and the shaft-side contact surface are brought into contact by a ring-shaped protruding valve body pressing contact part, the generation of particles caused by contact can be reduced. Furthermore, by forming the shaft and the shaft-side diaphragm from a composite material, the generation of particles can be reduced compared to the case where the shaft and the shaft-side diaphragm are formed from other materials. Additionally, by forming the shaft-side diaphragm from PTFE, excellent flexibility is achieved, and by forming the shaft-side contact surface from PFA, the generation of particles can be reduced.

[0019] A second embodiment of the present invention relates to a pressure-regulating valve according to a first embodiment, wherein the valve body and the valve body-side diaphragm are formed from a composite material, the valve body-side diaphragm is formed from PTFE, and the valve body-side contact surface is formed from PFA. According to this embodiment, by forming the valve body and the valve body-side diaphragm from a composite material, the generation of particles can be reduced compared to the case where the valve body and the valve body-side diaphragm are formed from other materials. Furthermore, by forming the valve body-side diaphragm from PTFE, excellent flexibility is achieved, and by forming the valve body-side contact surface from PFA, the generation of particles can be reduced.

[0020] A third embodiment of the present invention is a pressure regulating valve according to the first or second embodiment, wherein the contact surface on the valve body side is formed by PFA. According to this embodiment, the generation of particles can be reduced by forming the contact surface on the valve body side by PFA.

[0021] The fourth embodiment of the present invention is a pressure-regulating valve according to the first to third embodiments, wherein the valve closing contact portion and the valve body pressure contact portion are formed using PFA. According to this embodiment, by forming the valve closing contact portion and the valve body pressure contact portion using PFA, the generation of particles can be reduced.

[0022] The fifth embodiment of the present invention comprises, in a constant pressure valve according to the first to fourth embodiments, a body composed of a flow path forming body, a valve body side body, and a shaft side body; the flow path forming body forms an inlet flow path, an outlet flow path, and a flow rate control flow path; the valve body side body forms a valve body side pressurization chamber; the shaft side body forms a shaft side pressurization chamber; the valve body side diaphragm is fixed to the flow path forming body by the valve body side body; the shaft side diaphragm is fixed to the flow path forming body by the shaft side body; the valve body side body and the shaft side body are formed by PTFE; and the flow path forming body is formed by PFA. According to the present embodiment, the generation of particles can be reduced by forming the flow path forming body by PFA.

[0023] [Example]

[0024] Hereinafter, a pressure regulating valve according to one embodiment of the present invention will be described.

[0025] FIG. 1 is a cross-sectional view illustrating a pressure regulating valve according to the present embodiment, FIG. 1 (a) illustrates the entire pressure regulating valve, FIG. 1 (b) illustrates the shaft and shaft-side diaphragm, FIG. 1 (c) illustrates the valve body and valve-side diaphragm, and FIG. 1 (d) illustrates the body.

[0026] The constant pressure valve according to the present embodiment has an inlet passage (11) into which a fluid to be controlled flows, an outlet passage (12) into which a fluid to be controlled flows out, a flow rate control passage (13) located between the inlet passage (11) and the outlet passage (12), a valve body (21) disposed in the flow rate control passage (13), a valve body-side diaphragm (22) that displaces the valve body (21), a shaft (31) that presses the valve body (21), and a shaft-side diaphragm (32) that displaces the shaft (31).

[0027] In the constant pressure valve according to the present embodiment, an inflow path (11) is connected to one side of the valve body-side diaphragm (22), and a valve body-side pressurizing chamber (14) is formed on the other side of the valve body-side diaphragm (22). An outflow path (12) is connected to one side of the shaft-side diaphragm (32), and a shaft-side pressurizing chamber (15) is formed on the other side of the shaft-side diaphragm (32).

[0028] In the valve body side pressurization chamber (14), a pressing member (14a) that presses the valve body side diaphragm (22) is disposed. The pressing member (14a) is biased in the direction of the valve body side diaphragm (22) by an elastic member (14b).

[0029] Pressurized gas is introduced into the shaft-side pressurized chamber (15), and the shaft-side diaphragm (32) is pressed by the introduced pressurized gas.

[0030] In addition, in this embodiment, an elastic member (14b) is provided in the valve body-side pressurized chamber (14), but it may be biased by a fluid together with or instead of the elastic member (14b).

[0031] In addition, in this embodiment, pressurized gas is introduced into the shaft-side pressurized chamber (15), but a spring material may be provided together with or instead of the pressurized gas.

[0032] In addition, the black color in the drawing indicates that it is PFA.

[0033] As shown in FIG. 1(b), the shaft (31) and the shaft-side diaphragm (32) are integrally molded by resin as a shaft-side member (30). The shaft-side member (30) is formed from a composite material formed by bonding PTFE (tetrafluorinated ethylene resin) and PFA (tetrafluorinated ethylene perfluoroalkoxyethylene copolymer resin).

[0034] Although PFA has a shorter main chain than PTFE, it has side chains, so it is difficult to plastically deform and is less likely to generate dust (particles). The bonding of PTFE and PFA is performed by pressure and heat bonding.

[0035] The shaft (31) has a connecting portion (31a) that leads to the shaft-side diaphragm (32) and a contact portion (31b) that presses against the valve body (21).

[0036] The connecting portion (31a) has a truncated cone shape, the bottom surface is connected to the shaft-side diaphragm (32), and the top surface is connected to the contact portion (31b).

[0037] The contact portion (31b) has a cylindrical shape, one end of which connects to the ceiling surface of the connection portion (31a), and the other end of which becomes the shaft-side contact surface (31x).

[0038] The shaft-side contact surface (31x) is a surface perpendicular to the direction of movement of the valve body (21) and the shaft (31).

[0039] On the shaft-side contact surface (31x), a ring-shaped contact portion (31y) for pressurizing the valve body is formed. It is preferable to form the valve body pressurizing contact portion (31y) on the outer circumference of the shaft-side contact surface (31x). That is, it is preferable to make the outer diameter of the valve body pressurizing contact portion (31y) the same as the outer diameter of the contact portion (31b).

[0040] The shaft-side diaphragm (32) has a thick portion (32a) that extends to the shaft (31), a thin portion (32b) formed on the outer circumference of the thick portion (32a), and a fixed portion (32c) formed on the outer circumference of the thin portion (32b). The shaft-side diaphragm (32) extends from the center of the thick portion (32a) to the thick portion (32a).

[0041] The shaft-side diaphragm (32) is formed by PTFE, and the shaft-side contact surface (31x) and the valve body pressure contact portion (31y) are formed by PFA.

[0042] In this embodiment, the shaft-side diaphragm (32), the connection part (31a), and the contact part (31b) are formed on the connection part (31a) side by PTFE, and the shaft-side contact surface (31x) side of the contact part (31b) is formed by PFA.

[0043] As shown in FIG. 1 (c), the valve body (21) and the valve body-side diaphragm (22) are integrally molded by resin as a valve body-side member (20). The valve body-side member (20) is formed from a composite material formed by bonding PTFE and PFA.

[0044] The valve body (21) has a connection portion (21a) leading to a valve body-side diaphragm (22) and a contact portion (21b) that contacts a valve seat-side contact surface (41x) while being pressed by a shaft (31).

[0045] The connecting portion (21a) has a cylindrical shape, one end of which is connected to the valve body side diaphragm (22), and the other end of which is connected to the contact portion (21b).

[0046] The contact portion (21b) has a cylindrical shape, one end of which connects to one end of the connection portion (21a), and the other end of which becomes the valve body side contact surface (21x).

[0047] The contact portion (21b) is formed with an outer diameter larger than that of the connecting portion (21a).

[0048] The valve body contact surface (21x) is a surface perpendicular to the direction of movement of the valve body (21) and the shaft (31).

[0049] The valve body-side diaphragm (22) has a thin portion (22a) that extends to the valve body (21) and a fixed portion (22b) formed on the outer circumference of the thin portion (22a). The valve body-side diaphragm (22) extends from the center of the thin portion (22a) to the thin portion (22a).

[0050] The valve body side diaphragm (22) is formed by PTFE, and the valve body side contact surface (21x) is formed by PFA.

[0051] In this embodiment, the connection portion (21a) side of the valve body side diaphragm (22), connection portion (21a), and contact portion (21b) is formed by PTFE, and the valve body side contact surface (21x) side of the contact portion (21b) is formed by PFA.

[0052] As shown in (d) of FIG. 1, the body (40) has a body (41) for forming a flow path, a valve body side body (42), and a shaft side body (43).

[0053] The body (41) for forming the flow path forms an inlet flow path (11), an outlet flow path (12), and a flow rate control flow path (13).

[0054] The valve body side body (42) forms a valve body side pressurization chamber (14) and a breathing hole (14c) communicating with the valve body side pressurization chamber (14).

[0055] The valve body side member (20) is fixed to the flow path forming body (41) by the valve body side body (42).

[0056] The shaft-side body (43) forms a shaft-side pressurized chamber (15), a setting air port (15a) and an exhaust port (15b) that communicate with the shaft-side pressurized chamber (15).

[0057] The shaft-side member (30) is fixed to the body (41) for forming the flow path by the shaft-side body (43).

[0058] The valve seat side contact surface (41x) is formed as a surface perpendicular to the direction of movement of the valve body (21) and shaft (31) in the flow control path (13).

[0059] A valve closing contact portion (41y) protruding in a ring shape is formed on the valve seat side contact surface (41x). It is preferable to form the valve closing contact portion (41y) on the inner circumference of the valve seat side contact surface (41x). That is, it is preferable to make the inner diameter of the valve closing contact portion (41y) the same as the inner diameter of the valve seat side contact surface (41x).

[0060] The valve seat side contact surface (41x) and the valve closing contact portion (41y) are formed by PFA, and the body (41) for forming the flow path other than the valve seat side contact surface (41x), the valve body side body (42), and the shaft side body (43) are formed by PTFE.

[0061] FIG. 2 is a cross-sectional view illustrating the operating state of a pressure regulating valve according to the present embodiment, FIG. 2 (a) illustrates a state in which the controlled fluid is flowing, and FIG. 2 (b) illustrates a state in which the outflow side pressure is increased.

[0062] As shown in FIG. 2(a), the fluid to be controlled flowing in from the inlet channel (11) passes through the flow rate control channel (13) and flows out from the outlet channel (12).

[0063] The shaft-side diaphragm (32) is deformed in the direction in which the shaft (31) presses the valve body (21) by the gas pressure of the shaft-side pressurization chamber (15). The set pressure of the shaft-side pressurization chamber (15) is adjusted by introducing pressurized gas from the set air port (15a) or by discharging pressurized gas from the exhaust port (15b).

[0064] The valve body-side diaphragm (22) is deformed in the direction in which the valve body (21) presses the shaft (31) by the pressure of the valve body-side pressurizing chamber (14). The pressure of the valve body-side pressurizing chamber (14) is set by the elastic member (14b).

[0065] As shown in FIG. 2(a), when the fluid to be controlled is flowing in the flow control channel (13), the shaft (31) presses the valve body (21) by the shaft-side diaphragm (32), and since the valve body (21) presses the shaft (31) by the valve body-side diaphragm (22), the valve body (21) and the shaft (31) are in contact.

[0066] In the state shown in Fig. 2(a), when the inlet side pressure of the fluid to be controlled flowing in from the inlet channel (11) rises and becomes higher than the set pressure, the shaft side diaphragm (32) is displaced in the direction in which the shaft (31) is separated from the valve body (21) by the inlet side pressure.

[0067] As the shaft (31) is displaced in a direction that separates it from the valve body (21), the valve body (21) is displaced together with the shaft (31). That is, because the valve body (21) is displaced in a direction that approaches the valve seat side contact surface (41x), the flow control path (13) is narrowed (constricted).

[0068] By narrowing the flow control channel (13), it is possible to prevent the pressure on the outflow side caused by the fluid to be controlled flowing out from the outflow channel (12) from rising.

[0069] Meanwhile, in the state shown in Fig. 2(a), when the pressure on the inlet side of the fluid to be controlled flowing in from the inlet channel (11) decreases and becomes lower than the set pressure, the shaft-side diaphragm (32) is displaced in the direction in which the shaft (31) presses against the valve body (21).

[0070] As the shaft (31) is displaced in the direction of pressing the valve body (21), the valve body (21) is displaced. That is, because the valve body (21) is displaced in the direction of moving away from the valve seat side contact surface (41x), the flow control path (13) is expanded.

[0071] By expanding the flow control path (13), it is possible to prevent the pressure on the outflow side from decreasing due to the controlled fluid flowing out from the outflow path (12).

[0072] As such, the constant pressure valve according to the present embodiment can maintain a constant pressure on the outlet side of the fluid to be controlled flowing out from the outlet channel (12) by deforming the shaft-side diaphragm (32) even if the pressure on the inlet side of the fluid to be controlled flowing in from the inlet channel (11) fluctuates. In addition, since the valve body (21) is displaced together with the shaft (31), the valve body-side diaphragm (22) is also displaced along with the fluctuation of the pressure on the inlet side.

[0073] Figure 2(b) illustrates a state where the pressure on the outlet side is increased.

[0074] When the outflow side pressure increases, the shaft side diaphragm (32) is displaced in the direction in which the shaft (31) separates from the valve body (21) due to the outflow side pressure.

[0075] As the shaft (31) is displaced in a direction that separates it from the valve body (21), the valve body (21) is displaced together with the shaft (31), and the valve body (21) comes into contact with the valve seat side contact surface (41x).

[0076] Even when the valve body (21) is in contact with the valve seat side contact surface (41x), if the outflow side pressure is higher than the set pressure, the shaft (31) is separated from the valve body (21) as shown in Fig. 2 (b).

[0077] Therefore, even if the outflow side pressure increases and the valve body (21) comes into contact with the valve seat side contact surface (41x), the valve body (21) is subjected only to pressure from the elastic member (14b), and no load is applied due to the outflow side pressure.

[0078] FIG. 3 is a cross-sectional view illustrating a pressure regulating valve according to another embodiment of the present invention.

[0079] Functional members identical to those in the above examples are assigned the same reference numerals and their descriptions are omitted.

[0080] In this embodiment, the body (41) for forming the Euro is formed by PFA, which is different from the above embodiment, and the other configurations are the same.

[0081] As in the present embodiment, by forming the body (41) for forming the flow path entirely from PFA, the generation of particles in the inlet flow path (11), outlet flow path (12), and flow control flow path (13) can be reduced.

[0082] FIG. 4 is a cross-sectional view illustrating a pressure regulating valve according to another embodiment of the present invention.

[0083] Functional members identical to those in the above examples are assigned the same reference numerals and their descriptions are omitted.

[0084] In this embodiment, the valve body pressure contact portion (31y) and the valve blocking contact portion (41y) are provided on the valve body side contact surface (21x), which is different from the above embodiment, and the other configurations are the same.

[0085] As in the present embodiment, the contact portion (31y) for valve body pressure may be formed on the shaft-side contact surface (31x) instead of the valve body pressure contact surface (31x), and the contact portion (41y) for valve blockage may be formed on the valve body-side contact surface (21x) instead of the valve seat-side contact surface (41x).

[0086] In addition, the embodiment shown in FIG. 3 may be applied to the embodiment shown in FIG. 4.

[0087] As described above, according to the present embodiment, the valve body side contact surface (21x), shaft side contact surface (31x), and valve seat side contact surface (41x) are made perpendicular to the direction of movement of the valve body (21) and shaft (31), and the valve body side contact surface (21x) and the valve seat side contact surface (41x) are brought into contact by a ring-shaped protruding valve closing contact part (41y), and the valve body side contact surface (21x) and the shaft side contact surface (31x) are brought into contact by a ring-shaped protruding valve body pressing contact part (31y), thereby reducing the generation of particles caused by contact. In addition, by forming the shaft (31) and the shaft-side diaphragm (32) from a composite material, the generation of particles can be reduced compared to the case where the shaft (31) and the shaft-side diaphragm (32) are formed from other materials. Furthermore, by forming the shaft-side diaphragm (32) with PTFE, excellent flexibility is achieved, and by forming the shaft-side contact surface (31x) with PFA, the generation of particles can be reduced.

[0088] In addition, according to the present embodiment, by forming the valve body (21) and the valve body-side diaphragm (22) from a composite material, the generation of particles can be reduced compared to the case where the valve body (21) and the valve body-side diaphragm (22) are formed from other materials. Furthermore, by forming the valve body-side diaphragm (22) with PTFE, excellent flexibility is achieved, and by forming the valve body-side contact surface (21x) with PFA, the generation of particles can be reduced.

[0089] In addition, according to the present embodiment, the generation of particles can be reduced by forming the valve body side contact surface (21x) with PFA.

[0090] In addition, according to the present embodiment, the generation of particles can be reduced by forming the valve closing contact portion (41y) and the valve body pressing contact portion (31y) with PFA.

[0091] In addition, according to the present embodiment, the generation of particles can be reduced by forming the body (41) for forming the Euro using PFA.

[0092] For the constant pressure valves shown in FIGS. 1 and 2, a verification experiment was conducted on the amount of particles generated using a comparative example in which all components were made of PTFE. As a result, the constant pressure valve according to the present embodiment reduced the amount of particles generated to 1 / 10 of the amount of particles of 15 nm or less compared to the comparative example under normal control conditions. Industrial applicability

[0093] The present invention is suitable for a constant pressure valve requiring precise flow control and high cleanliness in the semiconductor manufacturing field. Explanation of the symbols

[0094] 11: Inflow of Euros 12: Leaked Euros 13: Flow control path 14: Valve body side pressurization chamber 14a: Compressing member 14b: Elastic member 14c: breathing hole 15: Shaft-side pressurization chamber 15a: Settings Airport 15b: Exhaust port 21: Valve body 21a: Connection part 21b: abutting part 21x: Valve body side contact surface 22: Valve body-side diaphragm 22a: Thin part 22b: Fixed part 30: Shaft-side member 31: Shaft 31a: Connection part 31b: abutting part 31x: Shaft-side contact surface 31y: Abutting part for valve body pressure 32: Shaft-side diaphragm 32a: Thick part 32b: Thin part 32c: Fixed part 40: Body 41: Body for Euro formation 41x: Valve seat side contact surface 41y: Butt for valve blocking 42: Valve body side body 43: Shaft-side body

Claims

Claim 1 A constant pressure valve having an inlet passage through which a controlled fluid flows in, an outlet passage through which the controlled fluid flows out, a flow control passage located between the inlet passage and the outlet passage, a valve body disposed in the flow control passage, a valve body-side diaphragm for displacing the valve body, a shaft for pressing the valve body, and a shaft-side diaphragm for displacing the shaft, wherein the inlet passage is connected to one side of the valve body-side diaphragm and a valve body-side pressurizing chamber is formed on the other side of the valve body-side diaphragm, and the outlet passage is connected to one side of the shaft-side diaphragm and a shaft-side pressurizing chamber is formed on the other side of the shaft-side diaphragm, and a constant pressure valve that maintains a constant outlet side pressure of the controlled fluid flowing out from the outlet passage by deforming the valve body-side diaphragm and the shaft-side diaphragm even when the inlet side pressure of the controlled fluid flowing in from the inlet passage fluctuates, wherein the valve body-side diaphragm and the shaft-side diaphragm are deformed, and wherein the valve body, with respect to the direction of movement of the valve body and the shaft A vertical contact surface on the valve body side is formed, and on the shaft, a shaft-side contact surface is formed perpendicular to the direction of movement of the valve body and the shaft, and on the flow control path, a valve seat-side contact surface is formed perpendicular to the direction of movement of the valve body and the shaft, and on the valve body-side contact surface or the valve seat-side contact surface, a ring-shaped protruding contact part for valve closing is formed, and on the valve body-side contact surface or the shaft-side contact surface, a ring-shaped protruding contact part for valve body pressure is formed, and on the valve body-side contact surface or the shaft-side contact surface, a ring-shaped protruding contact part for valve body pressure is formed, and the shaft and the shaft-side diaphragm are formed from a composite material formed by bonding PTFE and PFA, and the valve body and the valve body-side diaphragm are formed from the composite material, and the shaft-side diaphragm and the valve body-side diaphragm are formed by the PTFE, and the shaft-side contact surface, the valve body-side contact surface, the valve closing contact part, and the valve body A pressure contact portion is formed by the above PFA, andA constant pressure valve characterized by bringing the valve body side contact surface and the valve seat side contact surface into contact through the valve closing contact portion, and bringing the valve body side contact surface and the shaft side contact surface into contact through the valve body pressing contact portion. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 A constant pressure valve according to claim 1, wherein the body is composed of a body for forming a flow path, a valve body side body, and a shaft side body, wherein the body for forming the flow path forms the inlet flow path, the outlet flow path, and the flow control flow path, wherein the valve body side body forms the valve body side pressurization chamber, wherein the shaft side body forms the shaft side pressurization chamber, wherein the valve body side diaphragm is fixed to the body for forming the flow path by the valve body side body, and wherein the shaft side diaphragm is fixed to the body for forming the flow path by the shaft side body, wherein the valve body side body and the shaft side body are formed by PTFE, and the body for forming the flow path is formed by PFA.

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