Pressure regulating valve

Abstract

The objective of this invention is to provide a constant pressure valve with excellent diaphragm flexibility and reduced particulate generation. The means to solve the problem is a constant pressure valve, which has a valve body side abutment surface (21x) formed on the valve body (21) perpendicular to the movement direction of the valve body (21) and the shaft (31), a shaft side abutment surface (31x) perpendicular to the movement direction of the valve body (21) and the shaft (31) formed on the shaft (31), and a valve seat side abutment surface (41x) perpendicular to the movement direction of the valve body (21) and the shaft (31) formed in the flow control flow path (13). A valve blocking abutment (41y) protruding in an annular shape is formed on the valve body side abutment (21x) or the valve seat side abutment (41x). A valve body pressing abutment (31y) protruding in an annular shape is formed on the valve body side abutment (21x) or the shaft side abutment (31x). A shaft (31) and a shaft side diaphragm (32) are formed by a composite material that combines PTFE and cross-linked PTFE. A shaft side diaphragm (32) is formed by PTFE. A shaft side abutment (31x) is formed by cross-linked PTFE.

Description

Pressure regulating valve This invention relates to a constant pressure valve that can maintain a constant pressure on the outflow side of the controlled fluid flowing out of the outflow path, even if the inflow pressure of the controlled fluid flowing into the inflow path changes. In the cleaning and stripping processes of silicon wafer manufacturing for semiconductor devices, highly corrosive solutions such as strong acids and alkalis are used. Furthermore, the cleaning solutions used in these processes require extremely high purity, as they cannot tolerate any metallic or organic solutes originating from the valves. Therefore, the valves supplying these solutions are made of low-leaching materials with excellent acid and alkali resistance, namely fluoropolymers. The introduction of particulate matter into the flow path of fluids in semiconductor manufacturing processes significantly impacts product yield; therefore, the generation of particulate matter from the valves is unacceptable. Consequently, valves supplying high-purity solutions and ultrapure water employ a diaphragm structure to isolate the drive section from the contact section, preventing dust from the sliding parts from affecting the valve's contact area. For example, Patent Document 1 proposes a pressure regulating valve having an inflow path for the controlled fluid to flow into, an outflow path for the controlled fluid to flow out, a flow control path located between the inflow path and the outflow path, a valve body disposed in the flow control path, 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. The inflow path is connected to one side of the valve body-side diaphragm, and a valve body-side pressure chamber is formed on the other side of the valve body-side diaphragm. The outflow path is connected to one side of the shaft-side diaphragm, and a shaft-side pressure chamber is formed on the other side of the shaft-side diaphragm. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Publication No. 2000-193106 [The problem the invention aims to solve] PTFE (polytetrafluoroethylene) is a material known for its excellent chemical resistance, flexibility, and long lifespan. However, with the further miniaturization of semiconductor manufacturing processes (below 10nm), there is a growing demand for improvements in dust generation from machined surfaces, which even PTFE cannot adequately meet. Furthermore, cross-linked PTFE offers similar chemical resistance and flexibility to PTFE, but with superior wear resistance. However, its manufacturing process is more complex and expensive than that of PTFE, making it unsuitable for constructing all valve bodies. Therefore, the object of the present invention is to provide a pressure regulating valve with excellent diaphragm flexibility and reduced particulate generation. [Technical Means for Solving the Problem] The pressure regulating valve of the present invention according to claim 1 comprises: an inflow passage 11 for a controlled fluid to flow into; an outflow passage 12 for the controlled fluid to flow out; a flow control passage 13 located between the inflow passage 11 and the outflow passage 12; a valve body 21 disposed in the flow control passage 13; a valve body-side diaphragm 22 for displacing the valve body 21; a shaft 31 for pressing the valve body 21; and a shaft-side diaphragm 32 for displacing the shaft 31; and on the valve body side... One side of the diaphragm 22 is connected to the aforementioned inflow path 11, and a valve body-side pressurization chamber 14 is formed on the other side of the valve body-side diaphragm 22. One side of the aforementioned axial-side diaphragm 32 is connected to the aforementioned outflow path 12, and an axial-side pressurization chamber 15 is formed on the other side of the aforementioned axial-side diaphragm 32. Even if the inflow pressure of the controlled fluid flowing in from the aforementioned inflow path 11 changes, the aforementioned valve body-side diaphragm 22 and the aforementioned axial-side diaphragm 32 are deformed to prevent the aforementioned fluid flowing out from the aforementioned outflow path 12 from changing. A constant pressure valve that maintains a constant pressure on the outflow side of the controlled fluid is characterized by: a valve body-side abutment surface 21x perpendicular to the movement direction of the valve body 21 and the shaft 31 in the valve body 21; a shaft-side abutment surface 31x perpendicular to the movement direction of the valve body 21 and the shaft 31 in the shaft 31; and a valve seat-side abutment surface 41x perpendicular to the movement direction of the valve body 21 and the shaft 31 in the flow control path 13. A valve body-side abutment surface 21x or the aforementioned valve seat-side abutment surface 41x is formed with an annularly protruding valve blocking abutment portion 41y. A valve body pressing abutment portion 31y is formed with an annularly protruding valve body pressing abutment portion 31y on the aforementioned valve body-side abutment surface 21x or the aforementioned shaft-side abutment surface 31x. The aforementioned shaft 31 and the aforementioned shaft-side diaphragm 32 are formed by a composite material of bonded PTFE and cross-linked PTFE. The aforementioned shaft-side diaphragm 32 is formed by the aforementioned PTFE, and the aforementioned shaft-side abutment surface 31x is formed by the aforementioned cross-linked PTFE. The present invention of claim 2 is a pressure regulating valve of claim 1, wherein the aforementioned valve body 21 and the aforementioned valve body-side diaphragm 22 are formed by the aforementioned composite material, the aforementioned valve body-side diaphragm 22 is formed by the aforementioned PTFE, and the aforementioned valve body-side abutment surface 21x is formed by the aforementioned cross-linked PTFE. The present invention of claim 3 is a pressure regulating valve of claim 1, wherein the aforementioned valve body-side abutment surface 21x is formed by the aforementioned cross-linked PTFE. The present invention of claim 4 is a constant pressure valve of claim 1, wherein the aforementioned valve blocking abutment portion 41y and the aforementioned valve body pressing abutment portion 31y are formed by the aforementioned cross-linked PTFE.The present invention of claim 5 is a constant pressure valve of any one of claims 1 to 4, wherein a main body 40 is constituted by 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 inflow flow path 11, the outflow flow path 12, and the flow control flow path 13; the valve body side body 42 forms the valve body side pressure chamber 14; the shaft side body 43 forms the shaft side pressure 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; the valve body side body 42 and the shaft side body 43 are formed by PTFE; and the flow path forming body 41 is formed by cross-linked PTFE. The present invention as claimed in claim 6 is a constant pressure valve as claimed in any one of claims 1 to 4, wherein a main body 40 is constituted by a flow path forming main body 41, a valve body side main body 42, and a shaft side main body 43; the aforementioned flow path forming main body 41 forms the aforementioned inflow flow path 11, the aforementioned outflow flow path 12, and the aforementioned flow control flow path 13; the aforementioned valve body side main body 42 forms the aforementioned valve body side pressure chamber 14; the aforementioned shaft side main body 43 forms the aforementioned shaft side pressure chamber 15; the aforementioned valve body side diaphragm 22 is fixed to the aforementioned flow path forming main body 41 by the aforementioned valve body side main body 42; the aforementioned shaft side diaphragm 32 is fixed to the aforementioned flow path forming main body 41 by the aforementioned shaft side main body 43; the aforementioned valve body side main body 42 and the aforementioned shaft side main body 43 are formed by the aforementioned PTFE; and the aforementioned flow path forming main body 41 is formed by PFA. The invention described in claim 7 is a pressure regulating valve as described in claim 6, wherein the aforementioned cross-linked PTFE, which is joined to the aforementioned flow path forming body 41 by impedance heating, serves as the aforementioned valve seat side abutment surface 41x. The invention described in claim 8 is a pressure regulating valve as described in claim 7, wherein the aforementioned valve seat side abutment surface 41x is formed by a sheet-like cross-linked PTFE, and the aforementioned valve blocking abutment portion 41y is formed on the aforementioned valve body side abutment surface 21x. [Effects of the Invention]. According to the pressure regulating valve of the present invention, by making the valve body-side abutment surface, the shaft-side abutment surface, and the valve seat-side abutment surface into annular protruding valve blocking abutment portions perpendicular to the movement direction of the valve body and shaft, the valve body-side abutment surface abuts against the valve seat-side abutment surface, and then by using the annular protruding valve body pressing abutment portion, the valve body-side abutment surface abuts against the shaft-side abutment surface. Therefore, the generation of particles caused by abutment can be reduced. Furthermore, by forming the shaft and shaft-side diaphragm with a composite material, the generation of particles can be reduced compared to the case where the shaft and shaft-side diaphragm are formed with different components. Moreover, by forming the shaft-side diaphragm with PTFE, excellent flexibility can be achieved, and by forming the shaft-side abutment surface with cross-linked PTFE, the generation of particles can be reduced. The pressure regulating valve of the first embodiment of the present invention has a valve body side abutment surface perpendicular to the movement 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, a valve seat side abutment surface perpendicular to the movement direction of the valve body and the shaft in the flow control flow path, a valve blocking abutment portion protruding in an annular shape formed on the valve body side abutment surface or the valve seat side abutment surface, and a valve body pressing abutment portion protruding in an annular shape formed on the valve body side abutment surface or the shaft side abutment surface. The shaft and shaft side diaphragm are formed by a composite material of bonded PTFE and cross-linked PTFE, the shaft side diaphragm is formed by PTFE, and the shaft side abutment surface is formed by cross-linked PTFE. According to this embodiment, by making the valve body-side abutment surface, shaft-side abutment surface, and valve seat-side abutment surface into surfaces perpendicular to the movement direction of the valve body and shaft, and by forming annularly protruding valve blocking abutment portions, the valve body-side abutment surface abuts against the valve seat-side abutment surface, and by using annularly protruding valve body pressing abutment portions, the valve body-side abutment surface abuts against the shaft-side abutment surface. Therefore, the generation of particles caused by abutmentation can be reduced. Furthermore, by forming the shaft and shaft-side diaphragm with composite materials, the generation of particles can be reduced compared to the case where the shaft and shaft-side diaphragm are formed with different components. In addition, by forming the shaft-side diaphragm with PTFE, excellent flexibility can be achieved, and by forming the shaft-side abutment surface with cross-linked PTFE, the generation of particles can be reduced. The second embodiment of the present invention relates to the pressure regulating valve of the first embodiment. The valve body and valve body side diaphragm are formed of a composite material, the valve body side diaphragm is formed of PTFE, and the valve body side contact surface is formed of cross-linked PTFE. According to this embodiment, by forming the valve body and valve body side diaphragm with a composite material, the generation of particulate matter can be reduced compared to the case where the valve body and valve body side diaphragm are formed with different components. Furthermore, by forming the valve body side diaphragm with PTFE, excellent flexibility can be achieved, and by forming the valve body side contact surface with cross-linked PTFE, the generation of particulate matter can be reduced. The third embodiment of the present invention relates to the pressure regulating valve of the first embodiment, wherein the valve body side abutment surface is formed with cross-linked PTFE. According to this embodiment, by forming the valve body side abutment surface with cross-linked PTFE, the generation of particulate matter can be reduced. The fourth embodiment of the present invention relates to the pressure regulating valve of the first embodiment, wherein a valve blocking abutment and a valve body pressing abutment are formed by cross-linked PTFE. According to this embodiment, by forming the valve blocking abutment and the valve body pressing abutment with cross-linked PTFE, the generation of particulate matter can be reduced. The fifth embodiment of the present invention relates to the pressure regulating valve of embodiments 1 to 4. The valve body comprises 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 control flow path. The valve body side body forms a valve body side pressure chamber, and the shaft side body forms a shaft side pressure chamber. The valve body side diaphragm is fixed to the flow path forming body by the valve body side body, and 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 of PTFE, and the flow path forming body is formed of cross-linked PTFE. According to this embodiment, by forming the flow path forming body with cross-linked PTFE, particulate generation can be reduced. The sixth embodiment of the present invention pertains to the pressure regulating valve of embodiments 1 to 4. The main body comprises 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 control flow path. The valve body side body forms a valve body side pressure chamber, and the shaft side body forms a shaft side pressure chamber. The valve body side diaphragm is fixed to the flow path forming body via the valve body side body, and the shaft side diaphragm is fixed to the flow path forming body via the shaft side body. The valve body side body and the shaft side body are formed of PTFE, and the flow path forming body is formed of PFA. In this embodiment, by using low-viscosity PFA in the flow path forming body, the flow path forming body can be injection molded. The seventh embodiment of the present invention relates to the pressure regulating valve of the sixth embodiment, wherein cross-linked PTFE, bonded to the flow path forming body by impedance heating, is used as the valve seat-side contact surface. According to this embodiment, cross-linked PTFE is placed on the flow path forming body, and a heating block, directly heated by impedance heating, is pushed from the cross-linked PTFE side, thereby joining the valve seat-side contact surface. By directly heating the cross-linked PTFE to above its melting point temperature by the heating block, the cross-linked PTFE is softened or partially melted. Furthermore, the flow path forming body, made of PFA, is heated from the cross-linked PTFE, causing the contact interface with the cross-linked PTFE to melt, thus achieving a strong bond. Moreover, by directly heating the cross-linked PTFE by impedance heating, temperature control at the contact interface is easily achieved, resulting in high temperature control reactivity at the melting surface. Therefore, deformation of the flow path forming body is avoided by limiting heating to the contact interface, and the cross-linked PTFE can be planarized. The eighth embodiment of the present invention relates to the pressure regulating valve of the seventh embodiment. A valve seat-side abutment surface is formed using a sheet-like cross-linked PTFE, and a valve blocking abutment portion is formed on the valve body-side abutment surface. According to this embodiment, by forming the valve seat-side abutment surface with a sheet-like cross-linked PTFE, uneven melt flow rates are less likely to occur, allowing for shape maintenance and fusion bonding, and achieving uniform bond strength. [Example] The following describes a pressure regulating valve according to an embodiment of the present invention. FIG1 is a cross-sectional view showing the pressure regulating valve of this embodiment, wherein FIG1(a) shows the entire pressure regulating valve, FIG1(b) shows the shaft and shaft-side diaphragm, FIG1(c) shows the valve body and valve body-side diaphragm, and FIG1(d) shows the main body. The constant pressure valve of this embodiment includes: an inflow path 11 for the controlled fluid to flow into; an outflow path 12 for the controlled fluid to flow out of; a flow control path 13 located between the inflow path 11 and the outflow path 12; a valve body 21 disposed in the flow control path 13; a valve body-side diaphragm 22 for displacing the valve body 21; a shaft 31 for pressing the valve body 21; and a shaft-side diaphragm 32 for displacing the shaft 31. In this constant pressure valve, the inflow path 11 is connected to one side of the valve body-side diaphragm 22, and a valve body-side pressure chamber 14 is formed on the other side of the valve body-side diaphragm 22. The outflow path 12 is connected to one side of the shaft-side diaphragm 32, and a shaft-side pressure chamber 15 is formed on the other side of the shaft-side diaphragm 32. A pressing member 14a is disposed in the valve body-side pressure chamber 14 for pressing the valve body-side diaphragm 22. The pressing member 14a is pushed towards the valve body-side diaphragm 22 by the elastic member 14b. Pressurized gas is introduced into the axial-side pressurization chamber 15, and the introduced pressurized gas presses the axial-side diaphragm 32. Furthermore, in this embodiment, the valve body-side pressurization chamber 14 is provided with the elastic member 14b; however, the pushing can be performed by fluid and the elastic member 14b together, or by fluid replacing the elastic member 14b. Also, in this embodiment, pressurized gas is introduced into the axial-side pressurization chamber 15; however, a spring material can also be provided in addition to the pressurized gas, or a spring material can be provided instead of the pressurized gas. Furthermore, in the figure, the black area indicates cross-linked PTFE. As shown in Figure 1(b), the shaft 31 and the shaft-side diaphragm 32 are integrally molded from resin as shaft-side components 30. The shaft-side component 30 is formed by bonding PTFE (polytetrafluoroethylene resin) and cross-linked PTFE (tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin). Cross-linked PTFE is PTFE formed by the reaction of cross-linking independent molecules with each other, for example, by cross-linking methods such as chemical cross-linking and radiation cross-linking. Cross-linked PTFE has more than 1,000 times the wear resistance of PTFE in terms of sliding properties, and the material of the sliding object is less likely to be damaged. In addition, cross-linked PTFE has high resistance to deformation and is not easily deformed under load. Its resistance to deformation is better than that of PTFE at both room temperature and high temperature. In addition, the processability, chemical resistance, non-adhesiveness, and electrical properties of cross-linked PTFE are the same as those of PTFE, such as cutting, welding, and bonding. The bonding of PTFE and cross-linked PTFE is carried out by pressure and heat bonding. The shaft 31 has a connecting portion 31a connected to the shaft-side diaphragm 32 and an abutting portion 31b for pressing the valve body 21. The connecting portion 31a is truncated cone-shaped, with its bottom surface connected to the shaft-side diaphragm 32 and its top surface connected to the abutting portion 31b. The abutting portion 31b is cylindrical, with one end face connected to the top surface of the connecting portion 31a and the other end face forming a shaft-side abutting surface 31x. The shaft-side abutting surface 31x is perpendicular to the direction of movement of the valve body 21 and the shaft 31. A valve body pressing abutting portion 31y protruding in an annular shape is formed on the shaft-side abutting surface 31x. It is preferable that the valve body pressing abutting portion 31y is formed on the outer periphery of the shaft-side abutting surface 31x. That is, it is preferable that the outer diameter of the valve body pressing abutting portion 31y is the same as the outer diameter of the abutting portion 31b. The axial diaphragm 32 has a thickened portion 32a connected to the shaft 31; a thin-walled portion 32b formed on the outer periphery of the thickened portion 32a; and a fixing portion 32c formed on the outer periphery of the thin-walled portion 32b. The axial diaphragm 32 is connected to the thickened portion 32a at its central portion. The axial diaphragm 32 is formed of PTFE, and the axial abutment surface 31x and the valve body pressing abutment portion 31y are formed of cross-linked PTFE. In this embodiment, the connecting portion 31a side of the axial diaphragm 32, the connecting portion 31a, and the abutment portion 31b is formed of PTFE, and the axial abutment surface 31x side of the abutment portion 31b is formed of cross-linked PTFE. As shown in Figure 1(c), the valve body 21 and the valve body-side diaphragm 22 are integrally molded from resin as valve body-side components 20. The valve body-side components 20 are formed from a composite material of bonded PTFE and cross-linked PTFE. The valve body 21 has a connecting portion 21a connected to the valve body-side diaphragm 22; and an abutting portion 21b pressed by the shaft 31 and abutting against the valve seat-side abutting surface 41x. The connecting portion 21a is cylindrical, with one end face connected to the valve body-side diaphragm 22 and the other end face connected to the abutting portion 21b. The abutting portion 21b is cylindrical, with one end face connected to the other end face of the connecting portion 21a, and the other end face becoming the valve body-side abutting surface 21x. The abutting portion 21b is formed with an outer diameter larger than that of the connecting portion 21a. The valve body-side abutting surface 21x is a surface perpendicular to the direction of movement of the valve body 21 and the shaft 31. The valve body-side diaphragm 22 has a thin-walled portion 22a connected to the valve body 21, and a fixing portion 22b formed on the outer periphery of the thin-walled portion 22a. The valve body-side diaphragm 22 is connected to the thin-walled portion 22a at its central portion. The valve body-side diaphragm 22 is formed of PTFE, and the valve body-side abutment surface 21x is formed of cross-linked PTFE. In this embodiment, the connecting portion 21a side of the valve body-side diaphragm 22, the connecting portion 21a, and the abutment portion 21b is formed of PTFE, and the valve body-side abutment surface 21x side of the abutment portion 21b is formed of cross-linked PTFE. As shown in Figure 1(d), the main body 40 has a flow path forming main body 41, a valve body side main body 42, and a shaft side main body 43. The flow path forming main body 41 forms an inflow flow path 11, an outflow flow path 12, and a flow control flow path 13. The valve body side main body 42 forms a valve body side pressurization chamber 14 and a breather hole 14c communicating with the valve body side pressurization chamber 14. The valve body side member 20 is fixed to the flow path forming main body 41 by means of the valve body side main body 42. The shaft side main body 43 forms a shaft side pressurization chamber 15, a set air port 15a communicating with the shaft side pressurization chamber 15, and an exhaust port 15b. The shaft side member 30 is fixed to the flow path forming main body 41 by means of the shaft side main body 43. The valve seat-side abutment surface 41x is formed on the flow control path 13 as a surface perpendicular to the movement direction of the valve body 21 and the shaft 31. A valve blocking abutment portion 41y, protruding in an annular shape, is formed on the valve seat-side abutment surface 41x. It is preferable that the valve blocking abutment portion 41y is formed on the inner circumference of the valve seat-side abutment surface 41x. That is, it is preferable that the inner diameter of the valve blocking abutment portion 41y is the same as the inner diameter of the valve seat-side abutment surface 41x. The valve seat-side abutment surface 41x and the valve blocking abutment portion 41y are formed of cross-linked PTFE, while the flow path forming body 41, valve body body 42, and shaft body 43, excluding the valve body-side abutment surface 41x, are formed of PTFE. Furthermore, the valve seat-side abutment surface 41x and the valve blocking abutment portion 41y are formed by cross-linked PTFE, while the flow path forming body 41 other than the valve seat-side abutment surface 41x is formed by PFA (tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin), and the valve body-side body 42 and the shaft-side body 43 are formed by PTFE. By using low-viscosity PFA in the flow path forming body 41, the flow path forming body 41 can be injection molded. In order to join the valve seat-side abutment surface 41x formed by cross-linked PTFE to the flow path forming body 41 formed by PFA, cross-linked PTFE is placed on the flow path forming body 41, and a heating block that is directly heated by resistance heating is pushed from the cross-linked PTFE side. By directly heating the cross-linked PTFE to above its melting point using a heating block, the cross-linked PTFE is softened or partially melted. Furthermore, the flow path forming body 41, composed of PFA, is heated by the cross-linked PTFE, causing the contact interface with the cross-linked PTFE to melt, thus achieving a strong bond. Moreover, by directly heating the cross-linked PTFE using impedance heating, temperature control at the contact interface is easily achieved, resulting in high temperature control with high reactivity at the melting surface. Therefore, deformation of the flow path forming body 41 is avoided by limiting heating to the contact interface, allowing for the planarization of the cross-linked PTFE. For forming the valve seat side contact surface 41x, a sheet-like cross-linked PTFE with a thickness of 0.05 mm to 0.5 mm is preferred. If the sheet-like cross-linked PTFE is thinner than 0.05 mm, the PFA will penetrate to the sealing surface; if the sheet-like cross-linked PTFE is thicker than 0.5 mm, the melting time will be longer, resulting in deformation of the flow path forming body 41. Thus, by joining the valve seat-side abutment surface 41x based on cross-linked PTFE to the PFA-based flow path forming body 41, a bonding strength exceeding that of frictional bonding based on polymer entanglement can be achieved to bond the valve seat-side abutment surface 41x to the flow path forming body 41. Furthermore, by forming the valve seat-side abutment surface 41x with sheet-like cross-linked PTFE, uneven melt flow rates are less likely to occur, allowing for shape maintenance during melt bonding and achieving uniform bonding strength. Moreover, in this case, as shown in FIG4, a valve blocking abutment portion 41y is formed on the valve body-side abutment surface 21x. Figure 2 is a cross-sectional view showing the operating state of the constant pressure valve in this embodiment. Figure 2(a) shows the state of the controlled fluid flow, and Figure 2(b) shows the state of the outflow side pressure increasing. As shown in Figure 2(a), the controlled fluid flowing in from the inflow path 11 flows out from the outflow path 12 via the flow control path 13. The shaft-side diaphragm 32 deforms towards the shaft 31 and presses against 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 discharging pressurized gas from the exhaust port 15b. The valve body-side diaphragm 22 deforms towards the valve body 21 and presses against the shaft 31 by the pressing force of the valve body-side pressurization chamber 14. The pressing force of the valve body-side pressurization chamber 14 is set by the elastic member 14b. As shown in Figure 2(a), when the controlled fluid is flowing in the flow control path 13, the shaft 31 presses the valve body 21 by means of the shaft-side diaphragm 32, and the valve body 21 presses the shaft 31 by means of the valve body-side diaphragm 22. Therefore, the valve body 21 and the shaft 31 are in abutting state. In the state shown in Figure 2(a), when the inflow pressure of the controlled fluid flowing into the inflow path 11 increases and becomes higher than the set pressure, the axial diaphragm 32 is displaced in the direction of separation from the shaft 31 and the valve body 21 by the inflow pressure. Because the shaft 31 is displaced in the direction of separation 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 the direction closer to the valve seat side contact surface 41x, thus reducing the flow control path 13. By reducing the flow control path 13, the increase in outflow pressure caused by the controlled fluid flowing out of the outflow path 12 can be prevented. On the other hand, in the state shown in Figure 2(a), when the inflow pressure of the controlled fluid flowing into the inflow path 11 decreases and becomes lower than the set pressure, the axial diaphragm 32 is displaced in the direction of separation from the shaft 31 and the valve body 21. Because the shaft 31 is displaced in the direction of pressing the valve body 21, the valve body 21 is displaced. That is, the valve body 21 is displaced in a direction separating from the valve seat side contact surface 41x, thus expanding the flow control path 13. By expanding the flow control path 13, it is possible to prevent a decrease in the outflow side pressure caused by the controlled fluid flowing out of the outflow path 12. Thus, in this embodiment, even if the inflow side pressure of the controlled fluid flowing into the inflow path 11 changes, the constant pressure valve can maintain a constant outflow side pressure of the controlled fluid flowing out of the outflow path 12 by deforming the shaft-side diaphragm 32. Furthermore, in order to make the valve body 21 move together with the shaft 31, the valve body side diaphragm 22 also moves with the change in inflow side pressure. Figure 2(b) shows the state where the outflow side pressure is high. If the outflow side pressure is high, the shaft-side diaphragm 32 is displaced in the direction of separation between the shaft 31 and the valve body 21 due to the outflow side pressure. Due to the displacement of the shaft 31 in the direction of separation 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, then as shown in Figure 2(b), the shaft 31 separates from the valve body 21. Therefore, even though the valve body 21 is in contact with the valve seat side contact surface 41x due to the high outflow side pressure, only the pressing force of the elastic member 14b is applied to the valve body 21, and no load is applied due to the outflow side pressure. Figure 3 is a cross-sectional view showing a pressure regulating valve according to another embodiment of the present invention. Functional components identical to those in the foregoing embodiments are given the same reference numerals and their descriptions are omitted. In this embodiment, the flow path forming body 41 is formed using cross-linked PTFE, unlike in the foregoing embodiments; other structures remain the same. As shown in this embodiment, by forming all the flow path forming bodies 41 with cross-linked PTFE, the generation of particles in the inflow flow path 11, the outflow flow path 12, and the flow control flow path 13 can be reduced. Figure 4 is a cross-sectional view showing a pressure regulating valve according to another embodiment of the present invention. Functional components identical to those in the previous embodiments are given the same reference numerals and their descriptions are omitted. In this embodiment, the valve body pressing abutment portion 31y and the valve blocking abutment portion 41y are located on the valve body side abutment surface 21x, which differs from the previous embodiments; otherwise, the structure is the same. Alternatively, as in this embodiment, the valve body pressing abutment portion 31y can be formed on the valve body side abutment surface 21x instead of on the shaft side abutment surface 31x, and the valve blocking abutment portion 41y can be formed on the valve body side abutment surface 21x instead of on the valve seat side abutment surface 41x. Furthermore, the embodiment shown in Figure 3 can be applied to the embodiment shown in Figure 4. As described above, according to this embodiment, by making the valve body-side abutment surface 21x, the shaft-side abutment surface 31x, and the valve seat-side abutment surface 41x into surfaces perpendicular to the moving direction of the valve body 21 and the shaft 31, and by forming an annularly protruding valve blocking abutment portion 41y, the valve body-side abutment surface 21x abuts against the valve seat-side abutment surface 41x, and by using the annularly protruding valve body pressing abutment portion 31y, the valve body-side abutment surface 21x abuts against the shaft-side abutment surface 31x. Therefore, the generation of particles caused by abutment can be reduced. In addition, by forming the shaft 31 and the shaft-side diaphragm 32 with 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 with different components. Furthermore, by forming the shaft-side diaphragm 32 with PTFE, it can have excellent flexibility, and by forming the shaft-side abutment surface 31x with cross-linked PTFE, 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 with a composite material, the generation of particulate matter can be reduced compared to the case where the valve body 21 and the valve body side diaphragm 22 are formed with different components. Additionally, by forming the valve body side diaphragm 22 with PTFE, excellent flexibility can be achieved, and by forming the valve body side contact surface 21x with cross-linked PTFE, particulate matter generation can be reduced. Furthermore, according to this embodiment, by forming the valve body side contact surface 21x with cross-linked PTFE, particulate matter generation can be reduced. Furthermore, according to this embodiment, by forming the valve blocking contact portion 41y and the valve body pressing contact portion 31y with cross-linked PTFE, particulate matter generation can be reduced. Furthermore, according to this embodiment, by forming the flow path forming body 41 with cross-linked PTFE, particulate matter generation can be reduced. For the constant pressure valve shown in Figures 1 and 2, a verification experiment was conducted on the particle generation amount using a case where all components are made of PTFE as a comparative example. The results showed that, compared to the comparative example, the constant pressure valve of this embodiment reduced the generation amount of particles smaller than 15 nm to 1 / 10 under constant control. [Industrial Application Potential] This invention is applicable to constant pressure valves in the semiconductor manufacturing industry that require precise flow control and high-precision cleanliness. 11: Inflow path 12: Outflow path 13: Flow control path 14: Valve body side pressure chamber 14a: Pressing member 14b: Elastic member 14c: Breathing hole 15: Shaft side pressure chamber 15a: Setting air port 15b: Exhaust port 21: Valve body 21a: Connecting part 21b: Abutting part 21x: Valve body side abutting surface 22: Valve body side diaphragm 22a: Thin-walled part 22b: Fixing part 30: Shaft side member 31: Shaft 31a: Connecting part 31b: Abutting part 31x: Shaft side abutting surface 31y: Valve body pressing abutting part 32: Shaft side diaphragm 32a: Thick-walled part 32b: Thin-walled part 32c: Fixing part 40: Main body 41: Main body for flow path formation 41x: Valve seat side abutting surface 41y: Valve blocking abutting part 42: Valve body side main body 43: Shaft side main body [Figure 1] shows a cross-sectional view of a pressure regulating valve according to an embodiment of the present invention. [Figure 2] shows a cross-sectional view of the pressure regulating valve in its operating state. [Figure 3] shows a cross-sectional view of a pressure regulating valve according to another embodiment of the present invention. [Figure 4] shows a cross-sectional view of a pressure regulating valve according to another embodiment of the present invention. 11:Inflow path 12:Outflow path 13: Flow control path 14: Valve body side pressurization chamber 14a: Pressing component 14b: Elastic member 14c: Breathing hole 15: Axial pressure chamber 15a: Setting the air vent 15b: Exhaust port 20: Valve body side components 21: Valve body 21a: Connecting part 21b: Connecting part 21x: Valve body side contact surface 22: Valve body side diaphragm 22a: Thin-walled section 22b: Fixing part 30: Axonal components 31: Axis 31a: Connecting part 31b: Abutment part 31x: Axial side contact surface 31y: Valve body pressing contact part 32: Axial diaphragm 32a: Wall thickness section 32b: Thin-walled portion 32c: Fixing part 40: Main Body 41: Main body for flow path formation 41x: Valve seat side contact surface 41y: Valve blocking contact part 42: Valve body side main body 43: Axonal Body

Claims

1. A constant pressure valve comprising: an inflow passage for a controlled fluid to flow into; an outflow passage for the controlled fluid to flow out of; a flow control passage located between the inflow passage and the outflow 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 inflow passage is connected to one side of the valve body-side diaphragm, and a valve body-side pressurization chamber is formed on the other side of the valve body-side diaphragm; the outflow passage is connected to one side of the shaft-side diaphragm, and a shaft-side pressurization chamber is formed on the other side of the shaft-side diaphragm, wherein even if the inflow-side pressure of the controlled fluid flowing into the inflow passage changes, the outflow-side pressure of the controlled fluid flowing out of the outflow passage is maintained at a constant level by deformation of the valve body-side diaphragm and the shaft-side diaphragm, characterized in that: In the aforementioned valve body, a valve body side abutment surface perpendicular to the movement direction of the aforementioned valve body and the aforementioned shaft is formed. In the aforementioned shaft, a shaft side abutment surface perpendicular to the aforementioned movement direction of the aforementioned valve body and the aforementioned shaft is formed. In the aforementioned flow control flow path, a valve seat side abutment surface perpendicular to the movement direction of the aforementioned valve body and the aforementioned shaft is formed. An annular protruding valve blocking abutment portion is formed on the aforementioned valve body side abutment surface or the aforementioned valve seat side abutment surface. An annular protruding valve body pressing abutment portion is formed on the aforementioned valve body side abutment surface or the aforementioned shaft side abutment surface. The aforementioned shaft and the aforementioned shaft side diaphragm are formed by a composite material bonded with PTFE and cross-linked PTFE. The aforementioned shaft side diaphragm is formed by the aforementioned PTFE. The aforementioned shaft side abutment surface is formed by the aforementioned cross-linked PTFE.

2. As in request item 1, the pressure regulating valve, wherein, The valve body and the valve body side diaphragm are formed by the aforementioned composite material, the valve body side diaphragm is formed by the aforementioned PTFE, and the valve body side contact surface is formed by the aforementioned cross-linked PTFE.

3. As in request item 1, the pressure regulating valve, wherein, The aforementioned cross-linked PTFE is used to form the valve body side contact surface.

4. As in request item 1, the pressure regulating valve, wherein, The aforementioned valve blocking contact portion and the aforementioned valve body pressing contact portion are formed by the aforementioned cross-linked PTFE.

5. A pressure regulating valve as requested in any of items 1 to 4, wherein, The main body is composed of a flow path forming main body, a valve body side main body, and a shaft side main body. The flow path forming main body forms the aforementioned inflow flow path, the aforementioned outflow flow path, and the aforementioned flow control flow path. The aforementioned valve body side main body forms the aforementioned valve body side pressurization chamber. The aforementioned shaft side main body forms the aforementioned shaft side pressurization chamber. The aforementioned valve body side diaphragm is fixed to the aforementioned flow path forming main body by the aforementioned valve body side main body. The aforementioned shaft side diaphragm is fixed to the aforementioned flow path forming main body by the aforementioned shaft side main body. The aforementioned valve body side main body and the aforementioned shaft side main body are formed by the aforementioned PTFE. The aforementioned flow path forming main body is formed by the aforementioned cross-linked PTFE.

6. A pressure regulating valve as requested in any of items 1 to 4, wherein, The main 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 the aforementioned inflow flow path, the aforementioned outflow flow path, and the aforementioned flow control flow path. The aforementioned valve body side body forms the aforementioned valve body side pressure chamber. The aforementioned shaft side body forms the aforementioned shaft side pressure chamber. The aforementioned valve body side diaphragm is fixed to the aforementioned flow path forming body by the aforementioned valve body side body. The aforementioned shaft side diaphragm is fixed to the aforementioned flow path forming body by the aforementioned shaft side body. The aforementioned valve body side body and the aforementioned shaft side body are formed by the aforementioned PTFE. The aforementioned flow path forming body is formed by PFA.

7. As in request item 6, the pressure regulating valve, wherein, The aforementioned cross-linked PTFE, which is bonded to the aforementioned flow path forming body by impedance heating, serves as the aforementioned valve seat side abutment surface.

8. As in request item 7, the pressure regulating valve, wherein, The valve seat side abutment surface is formed by the aforementioned cross-linked PTFE in sheet form, and the aforementioned valve blocking abutment portion is formed on the aforementioned valve body side abutment surface.

Images