Diaphragm valve and valve element

Abstract

To provide a diaphragm valve capable of enhancing airtightness while having an alignment function by using a simple configuration even in use in a wide temperature environment.SOLUTION: A diaphragm valve 1 includes a valve element 10 suspended by a diaphragm 78 for hermetically sealing a valve chamber 61e and cooperating with a stem 76 so that an annular seal member 30 is located at a valve closing position abutting on a valve seat surface 61d and a valve opening position separating from the valve seat surface 61d. The valve element 10 includes: a seal holding member 40 that has a cylindrical part 41 and holds the annular seal member 30 at a concentric position with respect to a holding part 20; and an annular cushion member 50 nipped between the seal holding member 40 and the annular seal member 30 and held within an annular accommodation part 21 located at a concentric position with respect to the holding part 20. The annular seal member 30 is held within the annular accommodation part 21 while expanding in the radial outer side of the annular cushion member 50 to form a gap 23 between a surface facing a bottom surface 21c of the annular accommodation part 21 and the bottom surface 21c.SELECTED DRAWING: Figure 3A

Description

[Technical Field]

[0001] The present invention relates to a diaphragm valve and a valve element, and more particularly to a diaphragm valve and a valve element in which the valve element, which is suspended while hermetically sealing a valve chamber, moves to a valve opening / closing position in conjunction with a stem. [Background technology]

[0002] Conventionally, on-off valves used in gas supply piping systems for semiconductor manufacturing equipment, solar cell manufacturing equipment, liquid crystal manufacturing equipment, etc. are required to have little dead space and to suppress particle generation, and diaphragm valves are often used to meet these requirements. Some diaphragm valves have a sealing member such as a valve seat mounted not on the body side but on the valve element side, which moves in conjunction with the movement of the stem.

[0003] In order to increase the airtightness of the valve body and valve seat when the valve is closed, it is necessary to improve the ability of the seal member attached to the valve body to conform to the valve seat surface, and to improve the alignment performance of the valve body when it is suspended. Furthermore, due to the recent demand for high heat resistance, it is becoming increasingly important to maintain airtightness, including use in high-temperature environments where high-temperature control fluids of 300°C or higher are used. In order to meet these various demands, various techniques have been proposed.

[0004] For example, Patent Document 1 describes a diaphragm valve having an actuation mechanism that can move the diaphragm and associated valve element between an open position and a closed position without subjecting them to torsional loads. As the diaphragm valve described in Patent Document 1 progresses through the closing movement, the compressive force acting between the sealing surface 167 of the resilient seal ring 160 and the valve seat area increases. The force between the corner 156 of the rigid ring 152 and the valve seat area also increases, but to a lesser extent. This is because the less rigid and more resilient ring 158 more easily absorbs the compressive force, causing the rigid ring 152 to retract to some extent relative to the main body 78 and the resilient seal ring 160. This action allows the rigid ring 152 to continue contacting the valve seat area while increasing the sealing pressure between the surface 167 and the valve seat area. The compressive force acting within the resilient seal ring 160 also continues to apply a downward force to the sleeve 166 via the flange portion 168. When the valve is finally closed, the lower edge of the sleeve 166 makes line contact with the valve seat area along the circumference of the resilient seal ring 160.

[0005] Patent Document 2 describes a bellows seal valve, which is not a diaphragm valve but uses a suspended valve element, in which a valve element 9 suspended by a bellows 12 moves to a valve opening / closing position in conjunction with a valve axis 10 (corresponding to a stem). This bellows seal valve has a valve element 9 supported on a valve stem 10 that can reciprocate in the axial direction, and a metal sheet 14 that can abut against an annular valve seat 8 that protrudes from the wall of the valve chamber 4. A cavity 15 is provided behind the metal sheet 14. A cushion member 16 and a support member 17 are housed in this cavity 15.

[0006] Furthermore, Patent Document 3, like Patent Document 2, describes a bellows valve in which a valve element 14 suspended by a bellows 13b moves to a valve opening / closing position in conjunction with a spindle 16 (corresponding to a stem). In this bellows valve, a packing 30 is sandwiched between the bottom surface 14 a of the valve body 14 and the bottom surface 20 a of the disk 20 . [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Publication No. 62-288786 [Patent Document 2] Japanese Utility Model Application Publication No. 1-117971 [Patent Document 3] Publication No. 61-168375 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the diaphragm valve described in Patent Document 1 has a problem in that the elastic seal ring 160, which is the main sealing member for ensuring airtightness between the valve body and the valve seat when the valve is closed, is sandwiched and compressed between the rigid ring 152 and the sleeve 166, making it difficult to fully utilize its inherent cushioning properties, and as a result, it is difficult to improve airtightness. Furthermore, the bellows seal valve described in Patent Document 2 has an alignment mechanism 18 provided on the valve element 9 for alignment, which causes the valve element 9 to have a complicated structure. Furthermore, in the bellows valve described in Patent Document 3, the packing 30 is simply sandwiched between the bottom surface 14a of the valve element 14 and the bottom surface 20a of the disk 20 so that it overlaps in the axial direction, and no specific configuration for maintaining it in a position concentric with the axis is disclosed, so it is not possible to expect any alignment function from the valve element 14. Moreover, because the protrusions 23 and 24 protruding from the back side of the bottom surface 20a of the disk 20 press against the bottom surface 14a of the valve element 14 from below to form a seal, it is difficult to fully utilize the cushioning properties of the packing 30. For this reason, the bellows valve described in Patent Document 3 has the problem that it is difficult to improve airtightness.

[0009] The present invention was developed to solve the problems of the past, and its purpose is to provide a diaphragm valve and valve body that has a simple configuration, is equipped with an alignment function, and can improve airtightness even in a wide range of temperature environments. [Means for solving the problem]

[0010] In order to achieve the above object, the invention of claim 1 is a diaphragm valve comprising a valve body suspended by a diaphragm that airtightly seals a valve chamber, the valve body having a retaining portion that retains an annular seal member within an annular accommodating portion, and the valve body being linked to a stem so that the annular seal member is in a valve closed position where it abuts against a valve seat and in a valve open position where it is spaced from the valve seat, the valve body comprising: a seal retaining member having a tubular portion whose inner surface fits into the inner circumferential surface of the annular accommodating portion and holding the annular seal member concentrically with the retaining portion; and an annular cushion member that is sandwiched between the bottom surfaces of the seal retaining member and the annular seal member and is held within the annular accommodating portion concentrically with the retaining portion, with its inner circumferential surface fitting into the inner circumferential surface of the annular accommodating portion, the annular seal member being expanded radially outward from the annular cushion member and held within the annular accommodating portion in a state where a gap is formed between the bottom surface and the surface facing the bottom surface of the annular accommodating portion,

[0011] The invention according to claim 2 is a diaphragm valve in which the annular cushion member is made of a material with higher cushioning properties than the annular seal member.

[0012] The invention of claim 3 is a diaphragm valve in which the seat holding member has a flange portion that protrudes radially outward from the end of the cylindrical portion, and the annular sealing member has a stepped abutment surface formed thereon that abuts in a stepped manner against the outer peripheral surface of the cylindrical portion including the flange portion.

[0013] The invention of claim 4 is a diaphragm valve in which a recess is formed on the bottom surface of the annular accommodating section, the recess having a peripheral side surface slightly spaced from the outer peripheral surface of the annular cushion member, in which the annular cushion member is placed, and a gap is formed between the surface of the annular sealing member radially outward from the recess and the bottom surface of the annular accommodating section.

[0014] The invention according to claim 5 is a diaphragm valve in which the annular seal member is made of polyimide resin and the annular cushion member is made of perfluoroalkoxyalkane resin.

[0015] The invention of claim 6 is a valve body comprising: a seal retaining member that is suspended by a diaphragm that airtightly seals a valve chamber, and that has a retaining portion that holds an annular seal member within an annular accommodating portion, and that moves with the stem so that the annular seal member is in a valve closed position where it abuts the valve seat surface and in a valve open position where it is spaced from the valve seat surface; a cylindrical portion that fits its inner surface with the inner circumferential surface of the annular accommodating portion, and that holds the annular seal member in a position concentric with the retaining portion; and an annular cushion member that is sandwiched between the bottom side surfaces of the seal retaining member and the annular accommodating portion of the annular sealing member, and that has its inner circumferential surface fitted with the inner circumferential surface of the annular accommodating portion, and is held in the annular accommodating portion concentric with the retaining portion. [Effects of the Invention]

[0016] According to the invention of claim 1, the valve body comprises a seal retaining member having a cylindrical portion whose inner surface fits into the inner circumferential surface of the annular accommodating portion and holds the annular sealing member in a position concentric with the retaining portion, and an annular cushion member that is sandwiched between the bottom side surfaces of the seal retaining member and the annular sealing member and the bottom surface of the annular accommodating portion, and whose inner circumferential surface fits into the inner circumferential surface of the annular accommodating portion so as to be held within the annular accommodating portion in a position concentric with the retaining portion, and the annular sealing member is held within the annular accommodating portion in a state where it expands radially outward from the annular cushion member and forms a gap between the surface facing the bottom surface of the annular accommodating portion and the bottom surface. This simple configuration involves an annular cushion member that is fitted onto the inner surface of the annular accommodating portion and held concentrically with the retaining portion on the bottom side of the annular accommodating portion, and a gap provided between the annular sealing member in the outer diameter region of the annular cushion member and the bottom surface of the annular accommodating portion.When the annular cushion member abutting the valve seat is compressed toward the bottom surface together with the annular cushion member, the cushioning properties of the annular cushion member are effectively exerted by utilizing the gap between the annular sealing member and the annular accommodating portion, and the gap is utilized to deform for centering when the annular cushion member is compressed toward the bottom surface together with the annular cushion member. Furthermore, since the annular cushion member is located on the bottom side of the annular accommodating portion and is prevented from coming into contact with the control fluid by the seal retaining member and the annular sealing member, it is possible to prevent a decrease in cushioning properties due to the influence of temperature, and it is possible to use a material with high cushioning properties even if it has lower heat resistance than the annular sealing member. Therefore, according to the invention as defined in claim 1, it is possible to improve the alignment performance while maintaining airtightness with a simple configuration even in a wide range of temperature environments.

[0017] According to the invention of claim 2, the annular cushion member is made of a material with higher cushioning properties than the annular sealing member, and the cushioning properties of the annular cushion member are utilized to improve the conformability of the annular sealing member to the valve seat surface, thereby improving airtightness.

[0018] According to the invention of claim 3, the seal retaining member has a flange portion that protrudes radially outward in a flange-like manner from the end of the cylindrical portion, and the annular sealing member has a stepped abutment surface that abuts in a stepped manner against the outer peripheral surface of the cylindrical portion including the flange portion.As a result, when the annular sealing member abuts against the valve seat and is compressed, even if the annular sealing member moves axially relative to the seal retaining member, the control fluid does not penetrate through the stepped abutment portion between the seal retaining member and the annular sealing member, and therefore it is possible to prevent the control fluid from penetrating into the gap between the annular sealing member and the bottom surface of the annular accommodating portion.

[0019] According to the invention of claim 4, the annular sealing member has a recess formed on the bottom surface of the annular accommodating section, the recess having a peripheral side surface slightly spaced from the outer peripheral surface of the annular cushion member, in which the annular cushion member is placed, and a gap is formed between the surface of the annular sealing member radially outward from the recess and the bottom surface of the annular accommodating section, thereby making it possible to set the minimum necessary gap to enable the annular cushion member to exhibit its cushioning performance, and as a result, making it possible to set the minimum necessary gap to enhance airtightness.

[0020] According to the invention of claim 5, the annular sealing member is made of polyimide and the annular cushion member is made of perfluoroalkoxyalkane resin. Therefore, the part that comes into contact with the control fluid uses an annular sealing member made of polyimide resin that has a heat resistance of 300°C or more, while the part that does not come into contact with the control fluid uses an annular cushion member made of perfluoroalkoxyalkane resin that has a higher cushioning property than polyimide resin, although its heat resistance is not as high as 300°C or more. Therefore, even when used in an environment of 300°C or more, a simple configuration can be used to maintain airtightness and improve alignment performance.

[0021] According to the invention of claim 6, the device comprises a seal holding member having a cylindrical portion whose inner surface fits into the inner peripheral surface of the annular accommodating portion and holds the annular sealing member in a position concentric with the holding portion, and an annular cushion member that is sandwiched between the bottom side surfaces of the seal holding member and the annular sealing member and the bottom surface of the annular accommodating portion, and whose inner peripheral surface fits into the inner peripheral surface of the annular accommodating portion and is held within the annular accommodating portion in a position concentric with the holding portion, and the annular sealing member is held in the annular accommodating portion in a state where it expands radially outward from the annular cushion member and forms a gap between the surface facing the bottom surface of the annular accommodating portion and the bottom surface. This simple configuration involves an annular cushion member that is fitted into the cylindrical portion of the seal retaining member and held concentrically with the retaining portion on the bottom side of the annular accommodating portion, and a gap provided between the annular seal member in the outer diameter region of the annular cushion member and the bottom surface of the annular accommodating portion.When the annular cushion member abutting the valve seat is compressed toward the bottom surface of the annular accommodating portion, the cushioning properties of the annular cushion member are effectively exerted by utilizing the gap between the annular cushion member and the annular accommodating portion, and the annular seal member is deformed for alignment by utilizing the gap. Furthermore, since the annular cushion member is located on the bottom side of the annular accommodating portion and is prevented from coming into contact with the control fluid by the seal retaining member and the annular sealing member, it is possible to prevent a decrease in cushioning properties due to the influence of temperature, and it is possible to use a material with high cushioning properties even if it has lower heat resistance than the annular sealing member. Therefore, according to the invention as defined in claim 6, it is possible to improve the alignment performance while maintaining airtightness with a simple configuration even in a wide range of temperature environments. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is a cross-sectional view showing a schematic configuration of the diaphragm valve according to the embodiment in an open state. [Figure 2] 1 is a cross-sectional view showing a schematic configuration of a diaphragm valve according to an embodiment in a valve closed state. [Figure 3A] FIG. 2 is an enlarged view of the valve body of the diaphragm valve shown in FIG. [Figure 3B] 3B is a further enlarged view of the vicinity of the annular housing portion of the holding portion shown in FIG. 3A. FIG. [Figure 4] FIG. [Figure 5] FIG. 4 is a perspective view of the annular seal member as viewed from the bottom side of the annular housing portion. [Figure 6] FIG. 4 is a perspective view of the seal holding member as viewed from the bottom side of the annular housing portion. [Figure 7] 10A to 10C are diagrams for explaining the operation of each member provided in the holding portion of the valve body during the valve closing operation of the diaphragm valve. [Figure 8] FIG. 10 is a cross-sectional view of a valve body of a diaphragm valve having a different configuration from the diaphragm valve according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] An embodiment of a diaphragm valve 1 according to the present invention will be described in detail below with reference to FIGS. It should be noted that the present disclosure is not limited to the embodiments shown below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may include portions in which the dimensional relationships and ratios differ from one another. FIG. 1 is a cross-sectional view showing a schematic configuration of a diaphragm valve 1 according to an embodiment in an open state. FIG. 2 is a cross-sectional view showing a schematic configuration of a diaphragm valve 1 according to an embodiment in a closed state. FIG. 3A is an enlarged view of the valve body 10 of the diaphragm valve 1 shown in FIG. 1. FIG. 3B is an enlarged view further enlarging the vicinity of the annular housing portion 21 of the holding portion 20 shown in FIG. 3A. FIG. 4 is an exploded perspective view of the valve body 10. FIG. 5 is a perspective view of the annular seal member 30 as viewed from the surface facing the bottom surface 21c of the annular housing portion 21. FIG. 6 is a perspective view of the seal holding member 40 as viewed from the surface facing the bottom surface 21c of the annular housing portion 21. FIG. 7 is a view for explaining the operation of each component provided in the holding portion 20 of the valve body during the valve closing operation of the diaphragm valve 1.

[0024] The diaphragm valve 1 according to the embodiment of the present invention is intended to be used in an environment of, for example, 300 degrees or higher. However, this diaphragm valve 1 can also be used in environments other than high-temperature environments. For example, it can be used not only in a room-temperature environment but also in a low-temperature environment. The diaphragm valve 1 includes a valve element 10, a body 60, and an actuator 70 attached to the upper part of the body 60.

[0025] <About the valve body 10> The valve body 10 is suspended by a diaphragm 78 that hermetically seals the valve chamber 61e, and has a holding portion 20 that holds the annular sealing member 30, and is linked to the stem 76 so that the annular sealing member 30 can be positioned between a valve closed position where it abuts against the valve seat surface 61d and a valve open position where it is spaced apart from the valve seat surface 61d. As shown in FIGS. 3 and 4, the valve body 10 includes a holding portion 20, an annular seal member 30, a seal holding member 40, and an annular cushion member 50. As shown in FIG.

[0026] <Regarding the holding portion 20 of the valve body 10> The holding portion 20 is made of a metal material such as stainless steel, and has an annular housing portion 21 that holds the annular seal member 30 . The annular housing portion 21 has an opening 21a formed on the valve seat surface 61d side, and a cylindrical portion 22 that forms an inner circumferential surface 21b of the annular housing portion 21 in the center. This cylindrical portion 22 functions as a part that holds the seal holding member 40 and the annular cushion member 50 in the annular accommodating portion 21 while positioning them concentrically with the holding portion 20, by fitting its outer surface, which is the inner surface 21b of the annular accommodating portion 21, into the cylindrical inner surface 41b of the seal holding member 40 and the inner surface 50b of the annular cushion member 50.

[0027] <Annular seal member 30 of valve body 10> In this embodiment, the annular sealing member 30 is made of a highly heat-resistant polyimide resin, and is held within the annular accommodating portion 21 in a state in which it expands radially outward from the annular cushion member 50, forming a gap 23 between the surface facing the bottom surface 21c of the annular accommodating portion 21 and the bottom surface 21c. As described above, the annular seal member 30 is held in the annular accommodating portion 21 by the seal holding member 40 in a state where it is positioned concentrically with the holding portion 20 .

[0028] As shown in Figures 3B and 5, the annular sealing member 30 has a recess 31 formed on the surface facing the bottom surface 21c of the annular accommodating portion 21, the recess 31 having a peripheral side surface 31a slightly spaced from the outer peripheral surface 50a of the annular cushion member 50, in which the annular cushion member 50 is disposed.

[0029] The gap 23 is formed between a surface of the annular seal member 30 radially outward of the recess 31 of the annular seal member 30 and the bottom surface 21c of the annular accommodating portion 21. The width of this gap 23 is adjusted to an extent that when the valve body 10 moves to the valve closed position and the annular sealing member 30 abuts against the valve seat surface 61d and is compressed, the cushioning properties of the annular cushion member 50 can be effectively exerted, and the annular sealing member 30 can deform for alignment.

[0030] The bottom surface 31b of the recess 31 is provided with an annular protrusion 31c that is pressed against the surface of the annular cushion member 50. This annular protrusion 31c is a part that increases the degree of adhesion between the annular sealing member 30 and the annular cushion member 50 in an area radially inward of the area where the gap 23 is formed, so as to block the route through which the control fluid enters the gap 23 described above.

[0031] As shown in FIG. 3B, the annular seal member 30 is formed with a stepped abutment surface 32 that abuts in a stepped manner against the outer circumferential surface 41a of the cylindrical portion 41 including the flange portion 42 (described later) of the seal holding member 40. The stepped abutment surface 32 has a first abutment surface 32a that abuts against the outer peripheral surface 41a of the flange portion 42, a second abutment surface 32b that abuts against the surface of the flange portion 42 facing the bottom surface 21c of the annular accommodating portion 21, and a third abutment surface 32c that abuts against the outer peripheral surface of the end portion of the seal retaining member 40 on the bottom surface 21c side of the annular accommodating portion 21. The first abutment surface 32a and the third abutment surface 32c are the inner surfaces of the annular sealing member 30, which are described as surfaces that abut against the outer surface 41a of the seal holding member 40 when the annular sealing member 30 is positioned concentrically with the holding portion 20 by the seal holding member 40. When the valve body 10 is in the valve open position, i.e., when the annular sealing member 30 is in an elastically neutral state without being compressed, the first to third abutment surfaces 32a, 32b, and 32c of the annular sealing member 30 are in a state in which they abut against the corresponding surfaces of the seal retaining member 40.

[0032] Additionally, the outer peripheral surface 30b of the annular seal member 30 is inclined so that the outer diameter increases from the valve seat surface 61d side toward the bottom surface 21c side of the annular accommodating portion 21. This allows the annular sealing member 30 to have a small contact area with the annular accommodating portion 21, while ensuring that the outer peripheral surface 30b of the annular sealing member 30 is in close contact with the outer peripheral surface 21d of the annular accommodating portion 21 near the bottom surface 21c of the annular accommodating portion 21. Therefore, the control fluid is reliably prevented from penetrating into the gap 23 through the gap between the outer circumferential surface 30b of the annular seal member 30 and the outer circumferential surface 21d of the annular accommodating portion 21. <Regarding the seal retaining member 40 of the valve body 10>

[0033] The seal holding member 40 is made of a metal material such as stainless steel, and has a cylindrical portion 41 whose cylindrical inner surface 41b is fitted into the inner surface 21b of the annular accommodating portion 21, thereby holding the annular seal member 30 in a concentric position with the holding portion 20.

[0034] The seal holding member 40 has a flange portion 42 that projects radially outward from the end of a cylindrical portion 41 , and is adapted to abut against the stepped abutment surface 32 of the annular seal member 30 . The annular seal member 30 is held in the annular accommodating portion 21 at a position concentric with the holding portion 20 by fitting the inner peripheral surfaces 32a, 32c into the outer peripheral surface 41a of the cylindrical portion 41. In addition, the seal holding member 40 is adjusted so that the surface on the valve seat surface 61d side is lower than the valve seat abutment surface 30a of the annular seal member 30 on the same side, thereby preventing it from abutting against the valve seat surface 61d. <Annular cushion member 50 of valve body 10>

[0035] The annular cushion member 50 is an annular sheet member having cushioning properties, and in this embodiment is made of a perfluoroalkoxyalkane resin. That is, in this embodiment, the annular cushion member 50 is made of a material having higher cushioning properties than the annular seal member 30. In this embodiment, cushioning properties refer to the ability to flexibly conform and deform to the shape of another object that it comes into contact with, and the elasticity to restore the material from a compressed and deformed state. Moreover, high cushioning properties means high conformability while having elasticity that allows recovery from a compressed and deformed state. The annular cushion member 50 is sandwiched between the seal holding member 40 and the annular seal member 30 on the side of the bottom surface 21c of the annular accommodating portion 21 and the bottom surface 21c of the annular accommodating portion 21, and the inner peripheral surface 50b is fitted into the inner peripheral surface 21b of the annular accommodating portion 21, so that the annular cushion member 50 is held within the annular accommodating portion 21 at a position concentric with the holding portion 20.

[0036] The annular cushion member 50 may have cushioning properties similar to those of the annular seal member 30. The reason for this is that the annular cushion member 50 is disposed in a position where it does not come into direct contact with the high-temperature control fluid, and therefore, deterioration of the cushioning properties can be prevented even in a wide range of temperature environments, including high-temperature environments.

[0037] <About Body 60> The body 60 is made of a metal material and is integrally formed with a main body 61 having a flow path for gas serving as a control fluid, and a connecting portion 62 connected to the actuator 70 .

[0038] The main body 61 has a primary flow path 61a which is the gas inlet side and a secondary flow path 61b which is the gas outlet side, with a valve seat 61c having a flat valve seat surface 61d between which the annular sealing member 30 of the valve body 10 comes into contact and separates.

[0039] The connecting portion 62 is cylindrically protruding from the main body 61 above the valve seat 61c to which the actuator 70 is attached, and its inner surface is formed with an annular step portion 62a on which the bonnet 77 is seated while clamping the outer peripheral edge of the diaphragm 78. The connecting portion 62 connects the main body 61 and the actuator 70 with connecting members 65 and 66 interposed between the connecting portion 62 and the actuator 70 .

[0040] <About the actuator 70> The actuator 70 moves the stem 76 up and down to the valve opening and closing positions, and is provided in the case 70a with a lifting mechanism 71 that moves the stem 76 up and down, and a lifting and aligning mechanism 80 that has the function of lifting the valve element 10 in conjunction with the rising movement of the stem 76 when the valve is open, and the function of aligning the valve element 10 when the valve is closed.

[0041] <Regarding the lifting mechanism 71 of the actuator 70> The lifting mechanism 71 has a bellows 72 made of metal that has a bellows flange 72a at its lower end to receive the air introduced from the air inlet joint 70b, a plurality of cams 73 that are pivotally attached to the inner wall of the case 70a and have rollers 73a, 73b at both ends, and a spring 75 that applies force via a retainer 74 to move the stem 76 downward to the valve closed position.

[0042] The cam 73 has a roller 73a on one end arranged so as to be able to freely abut against the outer peripheral edge of the bellows flange 72a, and a roller 73b on the other end arranged in a groove formed in an annular shape on the upper outer peripheral surface of the stem 76. A plurality of such cams 73 are arranged dispersedly around the outer periphery of the stem 76.

[0043] <Regarding the lifting and aligning mechanism 80 of the actuator 70> The pulling-up and aligning mechanism 80 has a diaphragm piece 90 and a connecting member 100 . The pulling-up and aligning mechanism 80 includes a lower end recess 76 a provided at the lower end of the stem 76 .

[0044] <About the diaphragm piece 90 of the lifting and alignment mechanism 80> The diaphragm piece 90 is connected to the valve body 10 and held by the bonnet 77 so that it can move freely up and down, and the inner peripheral edge of the diaphragm 78, whose outer peripheral edge is sandwiched between the bonnet 77 and the body 60, is sandwiched between the holding portion 20 of the valve body 10. The diaphragm piece 90 has a cylindrical shape with a bottom, and is formed with an upper end recess 91 that is open at its upper end and into which the lower end of the connecting member 100 is loosely fitted. The shape of the diaphragm may be, for example, a wave shape or a dome shape.

[0045] In this embodiment, a spacer 93 is disposed on the bottom surface 91 a of the upper end recess 91 of the diaphragm piece 90 , and the upper surface 93 a of this spacer 93 forms the bottom surface 91 a of the upper end recess 91 . Therefore, for example, by adjusting the shape, material, hardness, surface condition, thickness, and number of spacers 93, it is possible to appropriately adjust the condition of the bottom surface of the upper end recess 91 that abuts against the connecting member 100. For example, by making the upper surface 93a of the spacer 93 flat or adjusting the surface roughness, the flatness of the bottom surface of the upper end recess 91 can be adjusted to a state suitable for alignment. Furthermore, by using a material for the spacer 93 that is different from that of the connecting member 100, the connecting member 100 is less likely to bite, and can be adjusted to a state suitable for alignment. Furthermore, by adjusting the thickness or number of the spacers 93, the contact state between the connecting member 100 and the bottom surface 91a of the upper end recess 91 with the spacers 93 therebetween can be adjusted to a state suitable for alignment.

[0046] On the other hand, the lower end of the diaphragm piece 90 is provided with a male threaded portion 92 which is screwed into the retaining portion 20 of the valve body 10 through a through hole formed in the center of the diaphragm 78, and the inner peripheral edge of the diaphragm 78 is clamped between the bottom surface of the diaphragm piece 90 around the base end of the male threaded portion 92 and the upper end surface of the retaining portion 20.

[0047] <Regarding the connecting member 100 of the lifting and aligning mechanism 80> The connecting member 100 has an outer shell that is approximately cylindrical, and a connecting through hole 102a is formed in a direction that is approximately perpendicular to the axial direction.The connecting member 100 is connected to the diaphragm piece 90 via a connecting pin 103 inserted into this connecting through hole 102a, and is also connected to the stem 76 via an engaging step 101a that engages with an engaging step 76b provided in the lower end recess 76a of the stem 76.

[0048] This connecting member 100 has an annular recess 100a formed on the outer circumferential surface thereof, whereby a head 101 is formed at the top, and a cylindrical body 102 is formed at the bottom below the annular recess 100a.

[0049] The head 101 is positioned loosely within the lower end recess 76a of the stem 76, with its lower surface forming the engaging surface 101b of the engaging step 101a which engages with the engaging step 76b provided in the lower end recess 76a of the stem 76.

[0050] The body 102 has the above-mentioned connecting through hole 102a formed therein, and is positioned loosely within the upper end recess 91 of the diaphragm piece 90 by a connecting pin 103 inserted into the connecting through hole 102a through a through hole (not shown) formed in the upper end recess 91 of the diaphragm piece 90.

[0051] The connecting through hole 102a has an elongated hole shape with the direction of rise and fall of the stem 76 as its longitudinal direction. More specifically, by setting the longitudinal dimension larger than the diameter of the connecting pin 103, there is provided play that allows the connecting member 100 to move downward so that when the stem 76 descends to close the valve, the lower end surface of the connecting member 100 abuts against the bottom surface of the upper end recess 91 of the diaphragm piece 90, i.e., the upper surface of the spacer 93.

[0052] <Diaphragm valve 1 opening and closing operation> The valve opening and closing operation of the diaphragm valve 1 will be described below with reference to FIGS. First, the valve opening operation of the diaphragm valve 1 will be described. When the diaphragm valve 1 changes from the valve closed state (see Figure 2) to the valve open state (see Figure 1), air is supplied into the bellows 72 through the air inlet joint 70b, causing the bellows 72 to expand, and the underside of the bellows flange 72a provided at the bottom of the bellows 72 comes into contact with the roller 73a on one end side of the cam 73. Then, the cam 73 rotates so as to tilt the other end side upward, and the roller 73b on the other end side lifts the stem 76, causing the stem 76 to rise.

[0053] When the stem 76 rises, the locking step 76b of the lower end recess 76a of the stem 76 abuts against the locking surface 101b of the connecting member 100, pulling up the connecting member 100, and the inner edge surface of the lower hole of the connecting through hole 102a of the connecting member 100 abuts against the connecting pin 103, lifting the diaphragm piece 90, causing the diaphragm piece 90 to rise.

[0054] When the diaphragm piece 90 rises, the valve element 10 connected to the diaphragm piece 90 also rises, and the annular seal member 30 moves away from the valve seat surface 61d, resulting in an open valve state. At this time, the diaphragm 78 is elastically restored to its bulged state with the periphery of the inner peripheral edge sandwiched between the diaphragm piece 90 and the holding portion 20 of the valve body 10 pulled upward. Furthermore, the annular seal member 30, which has been compressed in contact with the valve seat surface 61d, and the annular cushion member 50, which has been compressed via the annular seal member 30, are elastically restored to their original state.

[0055] Next, the valve closing operation of the diaphragm valve 1 will be described. When the diaphragm valve 1 changes from the above-mentioned valve open state to the valve closed state, the supply of air into the bellows 72 through the air inlet joint 70b is stopped, the elastic force of the spring 75 pushes down the retainer 74, and the stem 76 engaged with this retainer 74 descends.

[0056] When the stem 76 descends, the bottom surface of the lower end recess 76a of the stem 76 abuts against the arc-shaped curved surface 102c on the upper end surface of the connecting member 100, pushing the connecting member 100 down, and the arc-shaped curved surface 102c on the lower end surface of the connecting member 100 abuts against the upper surface of the spacer 93, pushing down the diaphragm piece 90. By pushing down the diaphragm piece 90 in this way, the valve element 10 connected to the diaphragm piece 90 descends, and the annular seal member 30 comes into contact with the valve seat surface 61d, resulting in a valve-closed state.

[0057] When the annular sealing member 30 descends in this manner, the downward movement of the stem 76 causes the connecting member 100 to abut against both the bottom surfaces of the lower end recess 76a of the stem and the upper end recess 91 of the diaphragm piece 90, transmitting the axial force of the stem 76 to the diaphragm piece 90. This is because the connecting member 100 is arranged in a loose fit state in each of the lower end recess 76a of the stem 76 and the upper end recess 91 of the diaphragm piece 90, and regardless of the posture of the diaphragm piece 90, the bottom surface of the lower end recess 76a of the stem 76 abuts against the upper end surface 101c, which forms an arc-shaped curved surface, of the connecting member 100, and the bottom surface of the upper end recess 91 of the diaphragm piece 90, or more specifically, the upper surface of the spacer 93 abuts against the lower end surface 102c, which forms an arc-shaped curved surface of the connecting member 100. Therefore, even if the diaphragm piece 90 is tilted relative to the axis of the stem 76 due to play between the diaphragm piece 90 and the bonnet 77, causing the valve body 10 connected to the diaphragm piece 90 to tilt, the diaphragm piece 90 is aligned, and the annular seal member 30 abuts against the valve seat surface 61d with the valve body 10 aligned.

[0058] After the annular sealing member 30 contacts the valve seat surface 61d in this manner, the valve body 10 moves further downward in conjunction with the stem 76, and as shown in Figure 7, the annular sealing member 30 is compressed by the reaction force it receives from the valve seat surface 61d, and the annular cushion member 50 that overlaps the annular sealing member 30 on the bottom side of the annular accommodating portion 21 is also compressed. When pressed against the annular sealing member 30, the annular cushion member 50 is elastically compressed and deformed while flexibly following the annular sealing member 30. In other words, the annular cushion member 50 is compressed and deformed in a state where it is in close contact with the annular sealing member 30 without generating any gap between itself and the annular sealing member 30, and in a state where it is pressed against the bottom surface 21c of the annular accommodating portion 21. Therefore, the annular seal member 30 in contact with the valve seat surface 61d is deformed to conform to the valve seat surface 61d with enhanced cushioning performance due to the cushioning properties of the annular cushion member 50 added to the cushioning properties of the annular seal member 30 itself. Furthermore, by providing the above-mentioned gap 23, the cushioning properties of the annular cushion member 50 can be effectively utilized while the annular sealing member 30 abuts against the valve seat surface 61d and is compressed, until it abuts against the bottom surface 21c of the annular accommodating portion 21. Furthermore, the annular seal member 30 deforms to align the valve body 10 by utilizing the gap 23 . That is, in this embodiment, in combination with the lifting and alignment mechanism 80 provided separately from the valve body 10, the alignment performance is further improved on the valve body 10 side.

[0059] When the annular sealing member 30 and the annular cushion member 50 are compressed due to the reaction force that the annular sealing member 30 receives from the valve seat surface 61d, a gap 24 is generated between the annular sealing member 30 and the seal retaining member 40, as shown in Figure 7. However, the stepped abutment surface 32 of the annular sealing member 30 that does not form this gap 24 expands toward the corresponding surface of the seal retaining member 40, thereby further adhering to the corresponding surface of the seal retaining member 40, thereby preventing the control fluid from penetrating into this gap.

[0060] <Effects of the embodiment> As described above, in the diaphragm valve 1 according to the embodiment, the valve body 10 comprises a seal retaining member 40 having a cylindrical portion 41 whose cylindrical inner surface 41b is fitted into the inner circumferential surface 21b of the annular accommodating portion 21, and retaining the annular sealing member 30 in a concentric position with the retaining portion 20, and an annular cushion member 50 which is sandwiched between the surfaces of the seal retaining member 40 and the annular sealing member 30 facing the bottom surface 21c of the annular accommodating portion 21 and the bottom surface 21c of the annular accommodating portion 21, and whose inner circumferential surface 50b is fitted into the inner circumferential surface 21b of the annular accommodating portion 21, and is retained within the annular accommodating portion 21 in a concentric position with the retaining portion 20, and the annular sealing member 30 is retained in the annular accommodating portion 21 in a state where a gap 23 is formed between the surface facing the bottom surface 21c of the annular accommodating portion 21 and the bottom surface 21c of the annular accommodating portion 21, expanding radially outward from the annular cushion member 50. As a result, with a simple configuration in which the annular cushion member 50 is fitted onto the inner surface 21b of the annular accommodating portion 21 and held concentrically with the retaining portion 20 on the bottom surface 21c side of the annular accommodating portion 21, and a gap 23 is provided between the annular sealing member 30 in the outer diameter region of the annular cushion member 50 and the bottom surface 21c of the annular accommodating portion 21, when the annular cushion member 50 is compressed toward the bottom surface 21c of the annular accommodating portion 21, the annular sealing member 30 abutting the valve seat surface 61d utilizes the gap 23 between itself and the annular accommodating portion 21 to effectively demonstrate the cushioning properties of the annular cushion member 50, and is compressed toward the bottom surface 21c together with the annular cushion member 50, while utilizing the gap 23 to deform for alignment. Furthermore, since the annular cushion member 50 is located on the bottom surface 21c side of the annular accommodating portion 21 and is prevented from coming into contact with the control fluid by the seal retaining member 40 and the annular sealing member 30, it is possible to prevent a decrease in cushioning properties due to the influence of temperature, and it is possible to use a material with high cushioning properties even if it has lower heat resistance than the annular sealing member 30. Therefore, the diaphragm valve 1 according to the embodiment can improve alignment performance while maintaining airtightness with a simple configuration, even in a wide range of temperature environments, including high-temperature environments.

[0061] Furthermore, according to the diaphragm valve 1 of the embodiment, the valve element 10 is aligned by a lifting and alignment mechanism 80 provided separately from the valve element 10, and the alignment function of the valve element 10 itself is further utilized to align the valve element 10, thereby improving alignment performance, and in particular, improving alignment performance for large valves that are difficult to align.

[0062] Furthermore, in the diaphragm valve 1 according to the embodiment, the annular cushion member 50 is made of a material with higher cushioning properties than the annular sealing member 30, and therefore the cushioning properties of the annular cushion member 50 can be utilized to improve the ability of the annular sealing member 30 to conform to the valve seat surface 61d, thereby improving airtightness.

[0063] Furthermore, in the diaphragm valve 1 according to the embodiment, the seal retaining member 40 has a flange portion 42 that protrudes radially outward in a flange-like manner from the end of the cylindrical portion 41, and the annular sealing member 30 has a stepped abutment surface 32 that abuts in a stepped manner against the outer surface 41a of the cylindrical portion 41, including the flange portion 42. Therefore, when the annular sealing member 30 abuts against the valve seat 61c and is compressed, even if the annular sealing member 30 moves axially relative to the seal retaining member 40, the control fluid does not penetrate through the stepped abutment portion between the seal retaining member 40 and the annular sealing member 30, and therefore the control fluid can be prevented from penetrating into the gap 23 between the annular sealing member 30 and the bottom surface 21c of the annular accommodating portion 21.

[0064] Furthermore, in the diaphragm valve 1 according to the embodiment, the annular sealing member 30 has a recess 31 formed on the surface of the bottom surface 21c of the annular accommodating portion 21, the recess 31 having a peripheral side surface 31a slightly spaced from the outer peripheral surface 50a of the annular cushion member 50, in which the annular cushion member 50 is disposed, and the gap 23 is formed between the surface of the annular sealing member 30 radially outward of the recess 31 and the bottom surface 21c of the annular accommodating portion 21, so that the minimum necessary gap 23 can be set to an extent that the annular cushion member 50 can exhibit its cushioning performance, and as a result, the minimum necessary gap 23 can be set to increase airtightness.

[0065] Furthermore, in the diaphragm valve 1 according to the embodiment, the annular sealing member 30 is made of polyimide and the annular cushion member 50 is made of perfluoroalkoxyalkane resin, so that the portion that comes into contact with the control fluid uses an annular sealing member 30 made of polyimide resin that has a heat resistance of 300°C or more, while the portion that does not come into contact with the control fluid uses an annular cushion member 50 made of perfluoroalkoxyalkane resin that has higher cushioning properties than polyimide resin, although its heat resistance is not as high as 300°C or more.As a result, even when used in an environment of 300°C or more, a simple configuration can be used and alignment performance can be improved while maintaining airtightness.

[0066] Furthermore, the valve body 10 according to the embodiment includes a seal retaining member 40 having a cylindrical portion 41 whose cylindrical inner surface 41b fits into the inner circumferential surface 21b of the annular accommodating portion 21, and retaining the annular sealing member 30 in a concentric position with the retaining portion 20; and an annular cushion member 50 that is sandwiched between the bottom side surfaces of the annular accommodating portion 21 of the seal retaining member 40 and the annular sealing member 30 and the bottom surface 21c of the annular accommodating portion 21, and whose inner circumferential surface 50b fits into the inner circumferential surface 21b of the annular accommodating portion 21, and is retained within the annular accommodating portion 21 in a concentric position with the retaining portion 20. The annular sealing member 30 is retained within the annular accommodating portion 21 in a state where it expands radially outward from the annular cushion member 50, forming a gap 23 between the surface facing the bottom surface 21c of the annular accommodating portion 21 and the bottom surface 21c of the annular accommodating portion 21. As a result, with a simple configuration in which the annular cushion member 50 is fitted into the cylindrical portion 41 of the seal holding member 40 and held concentrically with the holding portion 20 on the bottom surface 21c side of the annular accommodating portion 21, and a gap 23 is provided between the annular seal member 30 in the outer diameter region of the annular cushion member 50 and the bottom surface 21c of the annular accommodating portion 21, when the annular cushion member 50 is compressed toward the bottom surface 21c of the annular accommodating portion 21, the annular seal member 30 abutting against the valve seat surface 61d utilizes the gap 23 between itself and the annular accommodating portion 21 to effectively demonstrate the cushioning properties of the annular cushion member 50, and is compressed toward the bottom surface 21c together with the annular cushion member 50, while utilizing the gap 23 to deform for alignment. Furthermore, since the annular cushion member 50 is located on the bottom surface 21c side of the annular accommodating portion 21 and is prevented from coming into contact with the control fluid by the seal retaining member 40 and the annular sealing member 30, it is possible to prevent a decrease in cushioning properties due to the influence of temperature, and it is possible to use a material with high cushioning properties even if it has lower heat resistance than the annular sealing member 30.

[0067] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0068] For example, in the above embodiment, the annular sealing member 30 is made of polyimide resin and the annular cushion member 50 is made of perfluoroalkoxyalkane resin, but the annular sealing member 30 and the annular cushion member 50 are not limited to these resins, and other materials may be used as long as the annular sealing member 30 is a sealing material and the annular cushion member 50 is a member with cushioning properties.

[0069] Furthermore, in the above embodiment, an example in which the pulling-up and alignment mechanism 80 is provided is shown, but it is also possible to omit the pulling-up and alignment mechanism 80 and use only the alignment function of the valve element 10 for alignment. In other words, the diaphragm valve 1 may be configured such that the valve element 10 is connected to the stem 76 without the pulling-up and alignment mechanism 80 being interposed therebetween.

[0070] The present inventors conducted a high-temperature durability test on a diaphragm valve having a valve body configuration different from that of the diaphragm valve 1 of the above embodiment. FIG. 8 is a cross-sectional view of a valve element 210 used in a diaphragm valve having a different configuration from the diaphragm valve according to the embodiment. This diaphragm valve has a valve body 210 sandwiched between the surface of the annular sealing member 230 facing the bottom surface 221c of the annular accommodating portion 221 and the bottom surface 221c of the annular accommodating portion 221, and an annular cushion member 250 whose inner circumferential surface 250b is fitted into the inner circumferential surface 221b of the annular accommodating portion 221 and held within the annular accommodating portion 221 at a position concentric with the holding portion 220. In this diaphragm valve, the holding portion 220 has a crimped portion 220a, and the annular seal member 230 is held in the annular accommodating portion 221 by this crimped portion 220a.

[0071] The test conditions for the high temperature durability test are shown below. Test conditions: Annular seal material: Polyimide resin Annular cushion material: Perfluoroalkoxyalkane resin The valve was opened and closed 200,000 times in a temperature environment of 300°C.

[0072] The results of this high-temperature durability test showed that this diaphragm valve had no problems when opened and closed 100,000 times, but when opened and closed 200,000 times, particles were generated due to contact between the annular sealing member 230 and the crimped portion 220a.

[0073] On the other hand, the diaphragm valve 1 of this embodiment does not have a crimped portion 220a on the holding portion 20, and instead holds the annular seal member 30 using a seal holding member 40 that is a separate member from the holding portion 20, which is also effective in preventing the generation of particles. Furthermore, the outer peripheral surface 30b of the annular sealing member 30 is inclined so that the outer diameter expands from the valve seat surface 61d side toward the bottom surface 21c side of the annular accommodating portion 21, and the contact area between the annular sealing member 30 and the annular accommodating portion 21 is kept small, thereby effectively preventing the annular sealing member 30 from coming into contact with the annular accommodating portion 21 and generating particles. Furthermore, since the outer peripheral surface 30b of the annular sealing member 30 is inclined, a small gap 25 (see FIG. 3B) is formed between the outer peripheral surface 30b and the outer peripheral surface 21d of the annular accommodating portion 21 on the side of the opening 21a of the annular accommodating portion 21. Therefore, when the annular sealing member 30 is aligned using the gap 23, deformation for alignment can be more easily performed using this gap 25.

[0074] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0075] 1 diaphragm valve 10 Valve body 20 Holding part 21 Annular housing 21b Inner surface 21c bottom 23 Gap 30 Annular seal member 31 Recess 31a Circumferential side 32 Stepped contact surface 32a First contact surface 32b Second contact surface 32c Third contact surface 40 Seal retaining member 41 Cylindrical part 41a Outer surface 41b Cylinder inner surface 42 Tsuba 50 Annular cushion member 50a Outer surface 61d Valve seat surface 76 Stem

Claims

1. a valve body suspended by a diaphragm that airtightly seals a valve chamber, the valve body having a holding portion that holds an annular seal member within an annular housing portion, the valve body moving in conjunction with a stem so that the annular seal member is in a valve-closed position in contact with a valve seat surface and in a valve-open position away from the valve seat surface; the valve body includes a seal retaining member having a cylindrical portion whose cylindrical inner surface fits into the inner circumferential surface of the annular accommodating portion and retains the annular seal member in a concentric position with the retaining portion; and an annular cushion member that is sandwiched between the seal retaining member and the bottom surface of the annular accommodating portion of the annular seal member and the bottom surface, and that is retained in the annular accommodating portion concentric with the retaining portion with its inner circumferential surface fitted into the inner circumferential surface of the annular accommodating portion, a sealing member that is held in the annular accommodating portion in a state in which the sealing member expands radially outward from the annular cushion member and forms a gap between the bottom surface and a surface facing the bottom surface of the annular accommodating portion.

2. 2. The diaphragm valve according to claim 1, wherein the annular cushion member is made of a material having a higher cushioning property than the annular seal member.

3. The seal holding member has a flange portion that protrudes radially outward from an end of the cylindrical portion, 2. The diaphragm valve according to claim 1, wherein the annular seal member has a stepped abutment surface that abuts against the outer peripheral surface of the cylindrical portion including the flange portion in a stepped manner.

4. the annular sealing member has a recess formed on a bottom surface of the annular accommodating portion, the recess having a peripheral side surface slightly spaced from the outer peripheral surface of the annular cushion member, in which the annular cushion member is disposed; 2. The diaphragm valve according to claim 1, wherein the gap is formed between a surface of the annular seal member radially outward of the recess and a bottom surface of the annular accommodating portion.

5. the annular sealing member is made of polyimide resin, 5. The diaphragm valve according to claim 1, wherein the annular cushion member is made of a perfluoroalkoxyalkane resin.

6. the valve is suspended by a diaphragm that airtightly seals the valve chamber, and has a holding portion that holds an annular seal member within an annular housing portion, and is linked to the stem so that the annular seal member is in a valve-closed position in which it abuts on a valve seat surface and in a valve-open position away from the valve seat surface; a seal retaining member having a cylindrical portion whose inner surface fits into the inner circumferential surface of the annular accommodating portion and holds the annular sealing member in a concentric position with the holding portion; and an annular cushion member that is sandwiched between the bottom surface of the annular accommodating portion and the surfaces of the seal retaining member and the annular sealing member, and that has its inner circumferential surface fitted into the inner circumferential surface of the annular accommodating portion and is held within the annular accommodating portion in a concentric position with the holding portion.

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