Constant Pressure Valve

Abstract

To provide a constant-pressure valve which is excellent in bending performance of a diaphragm and can reduce the generation of particles.SOLUTION: A valve-body side abutment face 21x which is vertical to a moving direction of a valve body 21 and a shaft 31 is formed at the valve body 21, a shaft-side abutment face 31x vertical to the moving direction of the valve body 21 and the shaft 31 is formed at the shaft 31, a valve-seat side abutment face 41x vertical to the moving direction of the valve body 21 and the shaft 31 is formed at a flow rate control flow passage 13, a valve-closing abutment part 41y protruding in a ring shape is formed at the valve-body side abutment face 21x or the valve-seat side abutment face 41x, a valve body pressing abutment part 31y protruding in a ring shape is formed at the valve-body side abutment face 21x or the shaft-side abutment face 31x, the shaft 31 and a shaft-side diaphragm 32 are formed of composite materials obtained by joining PTFE and PFA, the shaft-side diaphragm 32 is formed of PTFE, and the shaft-side abutment face 31x is formed of PFA.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a constant pressure valve that maintains constant outlet pressure due to a controlled fluid flowing out from an outlet passage even if the inlet pressure due to the controlled fluid flowing in from an inlet passage fluctuates. [Background technology]

[0002] Highly corrosive chemicals such as strong acids and strong alkalis are used in the cleaning and peeling processes of silicon wafers used in the manufacture of semiconductor devices. In addition, metals and organic solutes from the valves are not permitted, and extremely high levels of cleanliness are required for the chemicals used in the cleaning and stripping processes. For this reason, fluororesin, which is a low-elution material with excellent acid and alkali resistance, is used for the valves that carry the chemicals. Since the inclusion of particles in the fluid flow path in the semiconductor manufacturing process has a significant impact on product yield, the generation of particles from valves is not permitted. For this reason, valves for supplying high-purity chemicals and ultrapure water are designed to have a structure in which a diaphragm separates the drive section from the liquid-contacting section so that dust generated from the sliding section does not affect the liquid-contacting section of the valve. For example, Patent Document 1 proposes a constant pressure valve having an inflow passage through which a controlled fluid flows in, an outflow passage through which the controlled fluid flows out, a flow rate control passage located between the inflow passage and the outflow passage, a valve body arranged in the flow rate control passage, a valve body side diaphragm that displaces the valve body, a shaft that presses the valve body, and a shaft side diaphragm that displaces the shaft, with the inflow passage communicating with one side of the valve body side diaphragm and a valve body side pressurizing chamber formed on the other side of the valve body side diaphragm, the outflow passage communicating with one side of the shaft side diaphragm, and the shaft side pressurizing chamber formed on the other side of the shaft side diaphragm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-193106 A Summary of the Invention [Problem to be solved by the invention]

[0004] PTFE (polytetrafluoroethylene) is a material that has excellent chemical resistance, flexibility, and long life. However, in recent years, with the development of further miniaturization of semiconductor manufacturing processes (10 nm process and below), improvements are also being required to reduce dust generation from the cutting surface, and even PTFE is no longer sufficient to meet these demands.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide a constant pressure valve which has a diaphragm with excellent flexibility and which reduces the generation of particles. [Means for solving the problem]

[0006] The constant pressure valve of the present invention as set forth in claim 1 comprises an inflow passage 11 through which a controlled fluid flows in, an outflow passage 12 through which the controlled fluid flows out, a flow rate control passage 13 located between the inflow passage 11 and the outflow passage 12, a valve element 21 disposed in the flow rate control passage 13, a valve element side diaphragm 22 for displacing the valve element 21, a shaft 31 for pressing the valve element 21, and a shaft side diaphragm 32 for displacing the shaft 31, one side of the valve element side diaphragm 22 is connected to the inflow passage 11, a valve element side pressurizing chamber 14 is formed on the other side of the valve element side diaphragm 22, one side of the shaft side diaphragm 32 is connected to the outflow passage 12, and a shaft side pressurizing chamber 15 is formed on the other side of the shaft side diaphragm 32, and even if the inflow side pressure due to the controlled fluid flowing in from the inflow passage 11 fluctuates, the valve element side diaphragm 22 and the shaft side diaphragm a valve body side abutment surface 21x perpendicular to a moving direction of the valve body 21 and the shaft 31 is formed on the valve body 21, a shaft side abutment surface 31x perpendicular to the moving direction of the valve body 21 and the shaft 31 is formed on the shaft 31, a valve seat side abutment surface 41x perpendicular to a moving direction of the valve body 21 and the shaft 31 is formed on the flow rate control flow path 13, a valve closing abutment portion 41y protruding in a ring shape is formed on the valve body side abutment surface 21x or the valve seat side abutment surface 41x, and a valve body pressing abutment portion 31y protruding in a ring shape is formed on the valve body side abutment surface 21x or the shaft side abutment surface 31x, the shaft 31 and the shaft side diaphragm 32 are formed of a composite material obtained 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 is formed by the PTFE, and the shaft side abutment surface 31x , the valve body side contact surface 21x, the valve closing contact portion 41y, and the valve body pressing contact portion 31y is formed by the PFA The valve closing contact portion 41y brings the valve body contact surface 21x into contact with the valve seat contact surface 41x, and the valve body pressing contact portion 31y brings the valve body contact surface 21x into contact with the shaft contact surface 31x. It is characterized by: Claim 2 The present invention as described herein is Claim 1a body 40 including a flow path forming body 41, a valve body side body 42, and a shaft side body 43, the flow path forming body 41 forming the inlet flow path 11, the outlet flow path 12, and the flow rate control flow path 13, the valve body side body 42 forming the valve body side pressurizing chamber 14, the shaft side body 43 forming the shaft side pressurizing chamber 15, the valve body side diaphragm 22 being fixed to the flow path forming body 41 by the valve body side body 42, the shaft side diaphragm 32 being fixed to the flow path forming body 41 by the shaft side body 43, the valve body side body 42 and the shaft side body 43 being formed of the PTFE, and the flow path forming body 41 being formed of the PFA. Effect of the Invention

[0007] 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 perpendicular to the movement direction of the valve body and the shaft, and the valve body side contact surface and the valve seat side contact surface are contacted by the valve closing contact portion protruding in a ring shape, and the valve body side contact surface and the shaft side contact surface are contacted by the valve body pressing contact portion protruding in a ring shape, so that the generation of particles due to 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 when the shaft and the shaft side diaphragm are formed from separate materials. Furthermore, by forming the shaft side diaphragm from PTFE, it has excellent flexibility, and by forming the shaft side contact surface from PFA, the generation of particles can be reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a constant pressure valve according to an embodiment of the present invention; [Diagram 2] Cross-sectional view showing the operation state of the constant pressure valve [Diagram 3] FIG. 4 is a cross-sectional view showing a constant pressure valve according to another embodiment of the present invention; [Figure 4] FIG. 11 is a cross-sectional view showing a constant pressure valve according to still another embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A constant pressure valve according to a first embodiment of the present invention has a valve element side abutment surface formed on the valve element and perpendicular to the movement direction of the shaft, a shaft side abutment surface formed on the shaft perpendicular to the movement direction of the valve element and the shaft, a valve seat side abutment surface formed on the flow control flow path perpendicular to the movement direction of the valve element and the shaft, a ring-shaped valve closing abutment portion is formed on the valve element side abutment surface or the valve seat side abutment surface, and a ring-shaped valve element pressing abutment portion is formed on the valve element side abutment surface or the shaft side abutment surface, the shaft and the shaft side diaphragm are formed of a composite material formed by bonding PTFE and PFA, The valve body and the valve body side diaphragm are formed from a composite material, Shaft side diaphragm and valve body side diaphragm The shaft contact surface is made of PTFE. , valve body side contact surface, valve closing contact portion, and valve body pressing contact portion Formed by PFA The valve closing contact portion brings the valve body contact surface into contact with the valve seat contact surface, and the valve body pressing contact portion brings the valve body contact surface into contact with the shaft contact surface. According to this embodiment, the valve body side abutment surface, the shaft side abutment surface, and the valve seat side abutment surface are surfaces perpendicular to the movement direction of the valve body and the shaft, the valve body side abutment surface and the valve seat side abutment surface are abutted by the valve closing abutment portion protruding in a ring shape, and the valve body side abutment surface and the shaft side abutment surface are abutted by the valve body pressing abutment portion protruding in a ring shape, so that generation of particles due to abutment can be reduced. Furthermore, by forming the shaft and the shaft side diaphragm from a composite material, generation of particles can be reduced compared to when the shaft and the shaft side diaphragm are formed from separate members. Furthermore, by forming the shaft side diaphragm from PTFE, it is excellent in flexibility, and by forming the shaft side abutment surface from PFA, generation of particles can be reduced. Furthermore, by forming the valve body and the valve body side diaphragm from a composite material, particle generation can be reduced compared to when the valve body and the valve body side diaphragm are formed from separate materials. Furthermore, by forming the valve body side diaphragm from PTFE, it has excellent flexibility, and by forming the valve body side contact surface, valve closing contact portion, and valve body pressing contact portion from PFA, particle generation can be reduced.

[0010] The present invention Second The embodiment of the present invention is No. 1In the constant pressure valve according to the embodiment, the body is composed of a flow path forming body, a valve body side body, and a shaft side body, the flow path forming body forms an inflow flow path, an outflow flow path, and a flow rate control flow path, the valve body side body forms a valve body side pressurizing chamber, the shaft side body forms a shaft side pressurizing 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 made of PTFE, and the flow path forming body is made of PFA. According to this embodiment, by forming the flow path forming body from PFA, the generation of particles can be reduced. EXAMPLES

[0011] A constant pressure valve according to one embodiment of the present invention will now be described. FIG. 1 is a cross-sectional view showing a constant pressure valve according to this embodiment, where FIG. 1(a) shows the entire constant pressure valve, FIG. 1(b) shows the shaft and shaft side diaphragm, FIG. 1(c) shows the valve body and valve body side diaphragm, and FIG. 1(d) shows the body.

[0012] The constant pressure valve of this embodiment has an inlet flow passage 11 through which the controlled fluid flows in, an outlet flow passage 12 through which the controlled fluid flows out, a flow rate control flow passage 13 located between the inlet flow passage 11 and the outlet flow passage 12, a valve body 21 arranged in the flow rate control flow 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. In the constant pressure valve of this embodiment, an inlet flow passage 11 is connected to one side of the valve body side diaphragm 22, a valve body side pressurized chamber 14 is formed on the other side of the valve body side diaphragm 22, an outlet flow passage 12 is connected to one side of the shaft side diaphragm 32, and a shaft side pressurized chamber 15 is formed on the other side of the shaft side diaphragm 32. A pressing member 14a that presses the valve element side diaphragm 22 is disposed in the valve element side pressurizing chamber 14. The pressing member 14a is biased in the direction of the valve element side diaphragm 22 by an elastic member 14b. Pressurized gas is introduced into the shaft side pressurizing chamber 15, and the shaft side diaphragm 32 is pressed by the introduced pressurized gas. In this embodiment, the valve body side pressurizing chamber 14 is provided with the elastic member 14b, but it may be biased by a fluid together with the elastic member 14b or in place of the elastic member 14b. 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 the pressurized gas or instead of the pressurized gas.

[0013] In the figure, the black color indicates PFA. 1(b), the shaft 31 and the shaft side diaphragm 32 are integrally molded from resin as the shaft side member 30. The shaft side member 30 is formed from a composite material in which PTFE (polytetrafluoroethylene resin) and PFA (polytetrafluoroethylene-perfluoroalkoxyethylene copolymer resin) are bonded together. PFA has a shorter main chain than PTFE, but because it has side chains, it is less prone to plastic deformation and less likely to generate dust (particles). PTFE and PFA are bonded together by pressure and heat bonding.

[0014] The shaft 31 has a connection portion 31 a connected to the shaft side diaphragm 32 and a contact portion 31 b that presses the valve body 21 . The connection portion 31a has a truncated cone shape, with its bottom surface connected to the shaft side diaphragm 32 and its top surface connected to the abutment portion 31b. The contact portion 31b has a cylindrical shape, one end face of which is connected to the top face of the connection portion 31a, and the other end face of which serves as a shaft-side contact surface 31x. The shaft side contact surface 31x is a surface perpendicular to the direction in which the valve body 21 and the shaft 31 move. A ring-shaped valve body pressing contact portion 31y is formed on the shaft side contact surface 31x. The valve body pressing contact portion 31y is preferably formed on the outer periphery of the shaft side contact surface 31x. In other words, the outer diameter of the valve body pressing contact portion 31y is preferably set to be the same as the outer diameter of the contact portion 31b.

[0015] The shaft side diaphragm 32 has a thick portion 32a connected to the shaft 31, a thin portion 32b formed on the outer periphery of the thick portion 32a, and a fixed portion 32c formed on the further outer periphery of the thin portion 32b. The shaft side diaphragm 32 is connected to the thick portion 32a at the center of the thick portion 32a. The shaft side diaphragm 32 is made of PTFE, and the shaft side contact surface 31x and the valve body pressing contact portion 31y are made of PFA. In this embodiment, the shaft side diaphragm 32, the connection portion 31a, and the connection portion 31a side of the abutment portion 31b are made of PTFE, and the shaft side abutment surface 31x side of the abutment portion 31b is made of PFA.

[0016] 1(c), the valve body 21 and the valve body side diaphragm 22 are integrally molded from resin as the valve body side member 20. The valve body side member 20 is formed from a composite material in which PTFE and PFA are bonded together. The valve body 21 has a connection portion 21a connected to the valve body side diaphragm 22, and a contact portion 21b that is pressed by the shaft 31 and comes into contact with the valve seat side contact surface 41x. The connection portion 21a has a cylindrical shape, one end face of which is connected to the valve body side diaphragm 22, and the other end face of which is connected to the abutment portion 21b. The contact portion 21b has a cylindrical shape, one end face of which is connected to the other end face of the connection portion 21a, and the other end face of which serves as the valve body side contact surface 21x. The contact portion 21b is formed with an outer diameter larger than that of the connection portion 21a. The valve body side contact surface 21x is a surface perpendicular to the direction in which the valve body 21 and the shaft 31 move.

[0017] The valve body side diaphragm 22 has a thin portion 22a connected to the valve body 21, and a fixing portion 22b formed on the outer periphery of the thin portion 22a. The valve body side diaphragm 22 is connected to the thin portion 22a at the center of the thin portion 22a. The valve body side diaphragm 22 is formed from PTFE, and the valve body side contact surface 21x is formed from PFA. In this embodiment, the valve body side diaphragm 22, the connection portion 21a, and the connection portion 21a side of the abutment portion 21b are made of PTFE, and the valve body side abutment surface 21x side of the abutment portion 21b is made of PFA.

[0018] As shown in FIG. 1( d ), the body 40 has a flow passage forming body 41 , a valve body side body 42 , and a shaft body side body 43 . The flow passage forming body 41 forms an inflow passage 11 , an outflow passage 12 , and a flow rate control passage 13 . The valve body 42 defines the valve pressurizing chamber 14 and a breathing hole 14 c that communicates with the valve pressurizing chamber 14 . The valve body side member 20 is fixed to a flow passage forming body 41 by a valve body side body . The shaft side body 43 defines a shaft side pressurizing chamber 15 , a set air port 15 a communicating with the shaft side pressurizing chamber 15 , and an exhaust port 15 b . The shaft side member 30 is fixed to the flow passage forming body 41 by the shaft side body 43 .

[0019] The valve seat side contact surface 41 x is formed in the flow rate control flow passage 13 as a surface perpendicular to the movement direction of the valve body 21 and the shaft 31 . A ring-shaped protruding valve closing contact portion 41y is formed on the valve seat side contact surface 41x. The valve closing contact portion 41y is preferably formed on the inner circumference of the valve seat side contact surface 41x. In other words, the inner diameter of the valve closing contact portion 41y is preferably the same as the inner diameter of the valve seat side contact surface 41x. The valve body side contact surface 41x and the valve closing contact portion 41y are made of PFA, and the flow passage forming body 41 other than the valve body side contact surface 41x, the valve body side body 42, and the shaft body 43 are made of PTFE.

[0020] 2A and 2B are cross-sectional views showing the operating states of the constant pressure valve according to this embodiment, where FIG. 2A shows a state in which the controlled fluid is flowing, and FIG. 2B shows a state in which the outlet side pressure has increased. As shown in FIG. 2( a ), the controlled fluid flowing in from an inflow channel 11 passes through a flow rate control channel 13 and flows out from an outflow channel 12 . The shaft-side diaphragm 32 is deformed in a direction in which the shaft 31 presses the valve body 21 due to the gas pressure in the shaft-side pressurized chamber 15. The set pressure of the shaft-side pressurized chamber 15 is adjusted by introducing pressurized gas from the set air port 15a or discharging pressurized gas from the exhaust port 15b. The valve element side diaphragm 22 is deformed by the pressing force of the valve element side pressurizing chamber 14 in a direction in which the valve element 21 presses the shaft 31. The pressing force of the valve element side pressurizing chamber 14 is set by the elastic member 14b. As shown in FIG. 2(a), when a controlled fluid is flowing through the flow control flow path 13, the shaft 31 presses against the valve body 21 via the shaft-side diaphragm 32, and the valve body 21 presses against the shaft 31 via the valve body-side diaphragm 22, so that the valve body 21 and the shaft 31 are in contact with each other.

[0021] In the state shown in Figure 2 (a), when the inlet side pressure due to the controlled fluid flowing in from the inlet flow passage 11 increases and becomes higher than the set pressure, the shaft side diaphragm 32 is displaced in a direction in which the shaft 31 moves away from the valve body 21 due to the inlet side pressure. As the shaft 31 is displaced in a direction away from the valve body 21, the valve body 21 is displaced together with the shaft 31. That is, the valve body 21 is displaced in a direction approaching the valve seat side abutment surface 41x, so that the flow rate control flow path 13 is narrowed. By narrowing the flow rate control flow passage 13, it is possible to prevent an increase in the outflow side pressure caused by the controlled fluid flowing out from the outflow flow passage 12. On the other hand, in the state shown in FIG. 2(a), when the inlet pressure due to the controlled fluid flowing in from the inlet flow passage 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 the valve body 21. The valve element 21 is displaced as a result of the shaft 31 being displaced in a direction pressing the valve element 21. That is, the valve element 21 is displaced in a direction away from the valve seat side abutment surface 41x, so that the flow rate control flow passage 13 expands. By expanding the flow rate control flow passage 13, it is possible to prevent a decrease in the outflow side pressure caused by the controlled fluid flowing out from the outflow passage 12. In this way, the constant pressure valve according to this embodiment can maintain a constant outlet pressure due to the controlled fluid flowing out of the outlet passage 12, even if the inlet pressure due to the controlled fluid flowing in from the inlet passage 11 fluctuates, by the deformation of the shaft side diaphragm 32. Note that, since the valve element 21 is displaced together with the shaft 31, the valve element side diaphragm 22 also displaces with the fluctuation in the inlet pressure.

[0022] Figure 2(b) shows the state where the outlet pressure is high. When the outlet pressure increases, the shaft side diaphragm 32 is displaced by the outlet pressure in a direction in which the shaft 31 moves away from the valve body 21 . When the shaft 31 is displaced in a direction away 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. 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 moves away from the valve body 21 as shown in FIG. 2(b). Therefore, even if the outflow pressure increases and the valve body 21 abuts against the valve seat abutment surface 41x, the valve body 21 is subjected to only the pressing force of the elastic member 14b, and no load due to the outflow pressure is applied to the valve body 21.

[0023] FIG. 3 is a cross-sectional view showing a constant pressure valve according to another embodiment of the present invention. The same reference numerals are used for the same functional members as those in the above embodiment, and the description thereof will be omitted. This embodiment differs from the above-described embodiment in that the flow passage forming body 41 is made of PFA, but the other configurations are the same. By forming the flow passage forming body 41 entirely from PFA as in this embodiment, generation of particles in the inflow flow passage 11, the outflow flow passage 12, and the flow rate control flow passage 13 can be reduced.

[0024] FIG. 4 is a cross-sectional view showing a constant pressure valve according to still another embodiment of the present invention. The same reference numerals are used for the same functional members as those in the above embodiment, and the description thereof will be omitted. This embodiment differs from the above embodiment in that a valve body pressing contact portion 31y and a valve closing contact portion 41y are provided on the valve body side contact surface 21x, but the other configurations are the same. As in this embodiment, the valve element pressing contact portion 31y may be formed on the shaft side contact surface 31x, and the valve closing contact portion 41y may be formed on the valve element side contact surface 21x, instead of the valve seat side contact surface 41x. The embodiment shown in FIG. 3 may be applied to the embodiment shown in FIG.

[0025] As described above, according to this embodiment, the valve body side abutment surface 21x, the shaft side abutment surface 31x, and the valve seat side abutment surface 41x are made perpendicular to the moving direction of the valve body 21 and the shaft 31, and the valve body side abutment surface 21x and the valve seat side abutment surface 41x are abutted by the valve closing abutment portion 41y protruding in a ring shape, and the valve body side abutment surface 21x and the shaft side abutment surface 31x are abutted by the valve body pressing abutment portion 31y protruding in a ring shape, so that the generation of particles due to abutment can be reduced. 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 when the shaft 31 and the shaft side diaphragm 32 are formed from separate members. In addition, by forming the shaft side diaphragm 32 from PTFE, it is excellent in flexibility, and by forming the shaft side abutment surface 31x from PFA, the generation of particles can be reduced. Furthermore, according to this 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 when the valve body 21 and the valve body side diaphragm 22 are formed from separate materials. Furthermore, by forming the valve body side diaphragm 22 from PTFE, it is possible to achieve excellent flexibility, and by forming the valve body side contact surface 21x from PFA, the generation of particles can be reduced. Furthermore, according to this embodiment, the valve body side contact surface 21x is made of PFA, so that generation of particles can be reduced. Furthermore, according to this embodiment, the valve closing contact portion 41y and the valve body pressing contact portion 31y are formed from PFA, thereby making it possible to reduce the generation of particles. Furthermore, according to this embodiment, the flow passage forming body 41 is made of PFA, so that generation of particles can be reduced.

[0026] A demonstration experiment was carried out on the amount of particles generated for the constant pressure valve shown in Figures 1 and 2, using a case in which all components were made of PTFE as a comparative example. As a result, the amount of particles generated of 15 nm or less was reduced to 1 / 10 in a steady control state for the constant pressure valve of this embodiment compared to the comparative example. [Industrial Applicability]

[0027] The present invention is suitable for constant pressure valves in the field of semiconductor manufacturing, where precise flow rate control and high cleanliness are required. [Explanation of symbols]

[0028] 11 Inlet Channel 12 Outlet Channel 13 Flow control channel 14 Valve body side pressurizing chamber 14a Pressing member 14b Elastic member 14c breathing hole 15 Shaft side pressure chamber 15a Setting Airport 15b Exhaust port 21 Valve body 21a Connection 21b Contact part 21x Valve body contact surface 22 Valve body side diaphragm 22a Thin wall part 22b Fixed part 30 Shaft side member 31 Shaft 31a Connection 31b Contact part 31x Shaft side contact surface 31y Valve body pressing contact part 32 Shaft side diaphragm 32a Thick part 32b Thin wall part 32c Fixed part 40 Body 41 Flow passage forming body 41x Valve seat contact surface 41y Valve blocking contact part 42 Valve body 43 Shaft side body

Claims

1. an inflow flow path into which a controlled fluid flows; an outlet flow path through which the controlled fluid flows; a flow control flow passage located between the inlet flow passage and the outlet flow passage; A valve body disposed in the flow rate control flow path; A valve body side diaphragm for displacing the valve body; A shaft that presses the valve body; a shaft-side diaphragm for displacing the shaft; having the inlet flow 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; the outlet flow 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; a constant pressure valve in which, even if an inlet pressure caused by the controlled fluid flowing in from the inlet flow path fluctuates, an outlet pressure caused by the controlled fluid flowing out from the outlet flow path is maintained constant by deformation of the valve body side diaphragm and the shaft side diaphragm, The valve body is provided with a valve body side abutment surface perpendicular to a moving direction of the valve body and the shaft, a shaft-side abutment surface perpendicular to the movement direction of the valve body and the shaft is formed on the shaft; a valve seat-side abutment surface perpendicular to a moving direction of the valve body and the shaft is formed in the flow rate control flow passage; A valve closing contact portion protruding in a ring shape is formed on the valve body contact surface or the valve seat contact surface, A ring-shaped valve body pressing contact portion is formed on the valve body contact surface or the shaft contact surface, The shaft and the shaft side diaphragm are formed of a composite material in which PTFE and PFA are bonded together, The valve body and the valve body side diaphragm are formed from the composite material, The shaft side diaphragm and the valve body side diaphragm are formed of the PTFE, the shaft side contact surface, the valve body side contact surface, the valve closing contact portion, and the valve body pressing contact portion are formed of the PFA, The valve closing contact portion brings the valve body contact surface into contact with the valve seat contact surface, and the valve body pressing contact portion brings the valve body contact surface into contact with the shaft contact surface. A constant pressure valve.

2. The body is made up of a flow passage forming body, a valve body, and a shaft body. the flow passage forming body forms the inlet flow passage, the outlet flow passage, and the flow rate control flow passage; the valve body defines the valve pressurizing chamber, the shaft side body defines the shaft side pressurizing chamber, the valve body-side diaphragm is fixed to the flow passage forming body by the valve body-side body, the shaft side diaphragm is fixed to the flow passage forming body by the shaft side body, The valve body and the shaft body are made of the PTFE. The flow passage forming body is formed from the PFA.

2. The constant pressure valve according to claim 1 .

Images