Fluid control valve

Abstract

To provide a fluid control valve capable of improving replaceability of fluid by suppressing retention of the fluid while maintaining durability of a valve seat of a valve body.SOLUTION: A fluid control valve 1 includes: a valve body 2 in which a first valve chamber 11 communicating with an inlet flow passage 8, a second valve chamber 12 communicating with an outlet flow passage 9 and a connection flow passage 13 connecting the first valve chamber and the second valve chamber are formed; a first diaphragm 3 mounted to the valve body to face the first valve chest; and a second diaphragm 4 mounted to the valve body to face the second valve chamber. In the valve body, a valve seat 15 is provided in a communication part of the first valve chamber and the connection flow passage. A valve element 3a coming into contact with / separating from the valve seat in a movement axis C direction is provided in the first diaphragm. A rib 25 is provided on at least the inlet flow passage 8 side of an outer peripheral surface of the valve element 3a, and a clearance S1 is formed between an outer peripheral surface of the rib 25 and an inner peripheral surface of the first valve chamber 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fluid control valve used in devices for transferring various fluids in various industrial fields such as semiconductor manufacturing, chemical plants, and food processing. [Background technology]

[0002] As shown in FIG. 14 , for example, a known conventional fluid control valve is a fluid control valve 101 comprising: a valve body 102 in which a first valve chamber 111 communicating with an inlet flow path 108, a second valve chamber 112 communicating with an outlet flow path 109, and a connecting flow path 113 connecting the first valve chamber 111 and the second valve chamber 112 are formed; a first diaphragm 103 attached to the valve body 102 so as to face the first valve chamber 111; and a second diaphragm 104 attached to the valve body 102 so as to face the second valve chamber 112. The valve body 102 is provided with a valve seat 115 at the communicating part between the first valve chamber 111 and the connecting flow path 113, and the first diaphragm 103 is provided with a valve element 103 a that moves toward and away from the valve seat 115 in the direction of a moving axis C. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-107606 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional fluid control valve 101, because the second valve chamber 112 is a uniform space along the circumferential direction, the fluid is likely to take a shortcut from the inlet flow path 108 to the outlet flow path 109 (see arrow A in FIG. 14), and an insufficient flow path is formed on the side of the second valve chamber 112 opposite the outlet flow path 109 (the back side), which can become a stagnation area for the fluid. If the proportion of this stagnation area increases, it takes longer to replace the fluid when switching the working fluid and starting up the device, resulting in a long start-up time for the device. Furthermore, dirt is likely to accumulate in the stagnation area, which can easily cause problems due to dirt at the destination of the fluid supply.

[0005] Patent Document 1 (see FIGS. 1 and 2) discloses a technique for suppressing fluid stagnation by providing a communication groove 27 on the side of the body 11 opposite the discharge passage 21, and by using the communication groove 27 to preferentially direct the fluid to the portion of the third fluid chamber R3 that is farthest from the discharge passage 21. However, with the technique disclosed in Patent Document 1, the communication groove 27 is located directly above the valve seat portion 25c, which reduces the thickness of the portion of the body 11 that includes the valve seat portion 25c, making it difficult to maintain the durability of the valve seat portion 25c.

[0006] The present invention has been made in consideration of the above-mentioned current situation, and aims to provide a fluid control valve that can suppress fluid retention and improve fluid replacement while maintaining the durability of the valve seat of the valve body. [Means for solving the problem]

[0007] The present invention is as follows. 1. A valve body having a first valve chamber communicating with an inlet flow path, a second valve chamber communicating with an outlet flow path, and a connecting flow path connecting the first valve chamber and the second valve chamber; a first diaphragm attached to the valve body so as to face the first valve chamber; a second diaphragm attached to the valve body so as to face the second valve chamber; Equipped with a valve seat is provided in the valve body at a communicating portion between the first valve chamber and the connecting flow path, The first diaphragm is provided with a valve body that approaches and separates from the valve seat in the direction of the movement axis. At least on the side of the inlet flow path of the outer peripheral surface of the valve body, ribs are provided. A fluid control valve, characterized in that a gap (S1) is formed between the outer peripheral surface of the rib and the inner peripheral surface of the first valve chamber. 2. The fluid control valve according to 1 above, wherein the rib is formed in an annular shape over the entire circumference of the outer peripheral surface of the valve body. 3. In the cross section of the rib perpendicular to the movement axis, when the difference between the inner diameter cross-sectional area (A1) of the first valve chamber and the outer diameter cross-sectional area (A2) of the rib is defined as the cross-sectional area (D1), and the difference between the inner diameter cross-sectional area (A1) of the first valve chamber and the outer diameter cross-sectional area (A3) of the valve body is defined as the cross-sectional area (D2), the cross-sectional area (D1) and the cross-sectional area (D2) satisfy D1 < D2, the ratio (D2 / D1) satisfies D2 / D1 ≧ 2, and the cross-sectional area (D1) is such that D3 ≦ D1 in the cross-sectional area (D3) which is the difference between the inner diameter cross-sectional area (A4) of the connection flow path and the outer diameter cross-sectional area (A5) of the shaft inserted into the connection flow path. The fluid control valve according to 1 above. 4. The second diaphragm has a shaft inserted into the connection flow path. 2. The fluid control valve according to 1 above, wherein the gap (S1) between the outer peripheral surface of the rib and the inner peripheral surface of the first valve chamber is not greater than the gap (S2) between the outer peripheral surface of the shaft and the inner peripheral surface of the connection flow path. 5. The fluid control valve according to 1 above, wherein the length (L) of the rib in the direction perpendicular to the movement axis is 1 mm or more.

Advantages of the Invention

[0008] According to the present invention, ribs are provided on at least the inlet flow path side of the outer peripheral surface of the valve body, and a gap is formed between the outer peripheral surface of the rib and the inner peripheral surface of the first valve chamber. Thereby, while maintaining the durability of the valve seat of the valve body, it is possible to suppress the retention of fluid and improve the replaceability of the fluid.

Brief Description of the Drawings

[0009] The present invention will be further described in the following detailed description by way of non-limiting examples of exemplary embodiments according to the present invention and with reference to the mentioned drawings, in which like reference numerals refer to like parts throughout the several views of the drawings.

[0010] [Figure 1] 1 is a vertical cross-sectional view of a fluid control valve according to a first embodiment. [Figure 2] FIG. 2 is an enlarged view of the portion indicated by the arrow II in FIG. [Figure 3] 3A and 3B are explanatory views of a first diaphragm according to the first embodiment, where FIG. 3A is a perspective view and FIG. 3B is a side view. [Figure 4] FIG. 4 is an explanatory diagram of the operation of the fluid control valve. [Figure 5] 1A and 1B are diagrams showing the results of fluid simulation of a fluid control valve, where FIG. 1A shows the results for the fluid control valve of the first embodiment, and FIG. 1B shows the results for a conventional fluid control valve. [Figure 6] FIG. 10 is a vertical cross-sectional view of a fluid control valve according to a second embodiment. [Figure 7] FIG. 7 is an enlarged view of the portion indicated by the arrow VII in FIG. 6. [Figure 8] 10A and 10B are explanatory views of a valve body according to a second embodiment, in which (a) is a perspective view and (b) is a plan view. [Figure 9] 6A and 6B are explanatory views of a first diaphragm according to another embodiment, in which (a) shows a cross-sectional view of a main part of a fluid control valve, and (b) shows a side view of the first diaphragm. [Figure 10] 10A and 10B are explanatory views of a first diaphragm according to still another embodiment, in which (a) shows a cross-sectional view of a main part of a fluid control valve, and (b) shows a side view of the first diaphragm. [Figure 11] 10A and 10B are explanatory views of a first diaphragm according to still another embodiment, in which (a) shows a cross-sectional view of a main part of a fluid control valve, and (b) shows a plan view of the first diaphragm. [Figure 12] 10A and 10B are explanatory diagrams of a valve body according to other embodiments, in which (a) shows an embodiment having a plurality of recesses, (b) shows an embodiment having a recess located in the radial middle of the valve chamber forming surface, and (c) shows an embodiment having a recess that is approximately rectangular in plan view. [Figure 13]10A and 10B are explanatory views of a recessed portion according to another embodiment. [Figure 14] FIG. 1 is a longitudinal sectional view of a conventional fluid control valve. DETAILED DESCRIPTION OF THE INVENTION

[0011] The matters set forth herein are for illustrative purposes only and are intended to provide an illustrative description of the embodiments of the present invention, with the aim of providing what is believed to be the most effective and easily understandable explanation of the principles and conceptual features of the present invention. In this regard, it is not intended to show structural details of the present invention beyond the extent necessary for a fundamental understanding of the present invention, and the description, taken together with the drawings, will make clear to those skilled in the art how some forms of the present invention may be actually embodied.

[0012] Hereinafter, the present invention will be specifically described by way of embodiments with reference to the drawings.

[0013] <Embodiment 1> 1, the fluid control valve 1A according to this embodiment includes a valve body 2, and a first diaphragm 3 and a second diaphragm 4 that are provided in the valve body 2 and move a valve element 3a toward and away from a valve seat 15 in the direction of a movement axis C. The fluid control valve 1A also includes a plate 5 attached to the upper part of the valve body 2, and a pressurizing unit 6 attached to the lower part of the valve body 2. The fluid control valve 1A functions as a constant pressure valve, as will be explained later in the description of its operation.

[0014] The valve body 2 is formed with a first valve chest 11 that communicates with the inlet flow path 8, a second valve chest 12 that communicates with the outlet flow path 9, and a connecting flow path 13 that connects the first valve chest 11 and the second valve chest 12. The first valve chest 11 is provided as a flat circular recess (specifically, a substantially cylindrical recess) in the center of the lower part of the valve body 2. The second valve chest 12 is provided as a flat circular recess (specifically, a substantially cylindrical recess) with a larger diameter than the first valve chest 11 in the center of the upper part of the valve body 2. The connecting flow path 13 is provided in the center of the valve body 2 as a flat circular hole (specifically, a substantially cylindrical hole) with a smaller diameter than the first valve chest 11 and the second valve chest 12.

[0015] The inlet flow path 8 extends linearly in a direction perpendicular to the movement axis C, with one end opening to the inner circumferential surface 11a of the first valve chamber 11. The outlet flow path 9 has a vertical flow path 9a that extends linearly along the movement axis C and has an upper end that opens to the bottom surface 12b of the second valve chamber 12, and a horizontal flow path 9b that is connected to the lower end of the vertical flow path 9a and extends linearly in a direction perpendicular to the movement axis C. The inlet flow path 8 and the outlet flow path 9 are arranged so that the axis of the inlet flow path 8 and the axis of the horizontal flow path 9b substantially coincide with each other when viewed from the direction of the movement axis C. However, the arrangement of the inlet flow path 8 and the outlet flow path 9 is not particularly limited. For example, when viewed from the direction of the movement axis C, the axis of the inlet flow path 8 and the axis of the horizontal flow path 9b may be substantially parallel, or the axis of the inlet flow path 8 and the axis of the horizontal flow path 9b may intersect.

[0016] The valve body 2 is provided with an annular valve seat 15 at the communicating portion between the first valve chamber 11 and the connecting flow path 13 (see FIG. 2). The valve seat 15 is located on the upper surface 11b of the first valve chamber 11, adjacent to the opening of the connecting flow path 13. However, the valve seat 15 may also be located on the upper surface 11b of the first valve chamber 11, away from the opening of the connecting flow path 13, outward (i.e., in the centrifugal direction about the movement axis C). The valve seat 15 is also formed by an annular rib that protrudes into the first valve chamber 11. However, if a rib is provided on the valve disc 3a side, the valve seat 15 may also be formed by an annular surface with which the rib comes into contact and separates.

[0017] The first diaphragm 3 is attached to the valve body 2 so as to face the first valve chamber 11 and separate the first valve chamber 11 from the outside. The first diaphragm 3 is provided with a valve element 3a that moves toward and away from the valve seat 15 in the direction of the movement axis C. Specifically, the first diaphragm 3 has the valve element 3a that moves in the direction of the movement axis C, an annular membrane portion 3b that movably supports the valve element 3a, and an outer peripheral edge portion 3c that is provided on the outer peripheral side of the membrane portion 3b. The valve element 3a is formed in a shape like a truncated cone with a cylinder connected to the top (approximately a truncated cone shape), and its upper surface serves as a valve seat abutment surface that moves toward and away from the valve seat 15. However, the shape of the valve element 3a is not particularly limited and may be formed in, for example, a truncated cone shape or a cylindrical shape.

[0018] The second diaphragm 4 is attached to the valve body 2 so as to face the second valve chamber 12 and separate the second valve chamber 12 from the outside. The second diaphragm 4 is provided with a shaft 4a that is inserted into the connecting flow path 13. Specifically, the second diaphragm 4 has the shaft 4a that moves in the direction of the movement axis C, an annular membrane portion 4b that movably supports the shaft 4a, and an outer peripheral edge portion 4c that is provided on the outer peripheral side of the membrane portion 4b. At least a portion of the shaft 4a is sized to be insertable into the connecting flow path 13. An annular gap S2 (e.g., 1 mm) is formed between the outer peripheral surface of the shaft 4a and the inner peripheral surface of the connecting flow path 13 (see FIG. 2). The gap S2 has a uniform value around the movement axis C.

[0019] The valve element 3a of the first diaphragm 3 and the shaft 4a of the second diaphragm 4 are not connected to each other and can be moved toward or away from each other. However, the valve element 3a and the shaft 4a may be connected by screwing, fitting, or other means. The first diaphragm 3 and the second diaphragm 4, particularly the membrane portions 3b and 4b, are preferably made of polytetrafluoroethylene (PTFE), which has flexibility and high bending resistance, since they are subjected to repeated bending. However, the valve element 3a is preferably made of perfluoroalkoxyalkane (PFA), which has low dust-generating properties, since it is prone to generating particles when it comes into contact with the valve seat 15. Therefore, the first diaphragm 3 may be configured such that only the valve seat contact surface of the valve element 3a is made of PFA, and the remaining portions are made of PTFE. The valve body 2 may be made of an appropriate material, such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroalkoxyalkane (PFA), or polychlorotrifluoroethylene (PCTFE).

[0020] The plate 5 is attached to the top of the valve body 2 with fasteners (not shown), such as bolts, so that the outer peripheral edge 4c of the second diaphragm 4 is sandwiched between the plate 5 and the valve body 2. A working fluid supply port 5a is formed in the bottom surface of the plate 5. A pressurized chamber 5b, which is separated from the second valve chamber 12, is formed between the plate 5 and the top surface of the second diaphragm 4. By supplying working fluid to the pressurized chamber 5b through the working fluid supply port 5a and varying the pressure within the pressurized chamber 5b, the valve element 3a of the first diaphragm 3 together with the shaft 4a of the second diaphragm 4 can be moved up and down to approach or move away from the valve seat 15.

[0021] The pressurizing unit 6 is attached to the bottom of the valve body 2 with fasteners (not shown) such as bolts so as to sandwich the outer peripheral edge 3c of the first diaphragm 3 between the valve body 2. The pressurizing unit 6 has a movable body 6b that moves in the direction of the movement axis C within a pressurizing chamber 6a formed between the assembled housings 22a and 22b, a biasing spring 6c that biases the movable body 6b in a direction toward the first valve chamber 11, and a stem 6d extending from the top of the movable body 6b. The valve body 3a of the first diaphragm 3 is connected to the tip of the stem 6d by screwing, fitting, or the like.

[0022] 2 and 3, the outer peripheral surface of the valve disc 3a is provided with ribs 25 that guide the flow direction of a portion of the fluid flowing from the inlet flow path 8 into the first valve chest 11. Specifically, the ribs 25 guide a portion of the fluid in the inlet flow path 8 so that it flows into the first valve chest 11 in a direction away from the connecting flow path 13 (specifically, diagonally downward) (see FIG. 4). In other words, the ribs 25 function as resistance portions that prevent a portion of the fluid in the inlet flow path 8 from flowing into the first valve chest 11 in a direction toward the connecting flow path 13 (specifically, diagonally upward). The ribs 25 can guide, for example, 40% or more (preferably 60% or more, and more preferably 80% or more) of the total flow rate of the fluid flowing from the inlet flow path 8 into the first valve chest 11 diagonally downward.

[0023] The rib 25 is formed in an annular shape around the entire outer circumferential surface of the valve disc 3a. Specifically, the rib 25 is provided in a flange-like projection on the upper part of the outer circumferential surface of the valve disc 3a. The rib 25 is located above the opening of the inlet flow path 8 to the first valve chamber 11 when the valve disc 3a is separated from the valve seat 15 and the gap S3 therebetween is set to a predetermined value (i.e., a value at which a predetermined flow rate of fluid flows through the fluid control valve) (see FIG. 2).

[0024] The length (protrusion) L in the direction orthogonal to the movement axis C of the rib 25 is set to be 1 mm or more. This length L is usually set to be 2 mm or less. An annular gap S1 (for example, 0.5 mm) is formed between the outer peripheral surface of the rib 25 and the inner peripheral surface of the first valve chamber 11. The gap S1 has a uniform value around the movement axis C. As will be described in the actions hereinafter, the fluid that has once been guided downward by the rib 25 and flowed into the first valve chamber 11 is rectified in the flow direction by the gap S1 so that the traveling direction is rectified along the direction (i.e., the vertical direction) along the movement axis C (see FIG. 4). The size of this gap S1 is not particularly limited, but from the viewpoint of the fluid rectification property, it is preferably set to a value equal to or less than the value of the above-described gap S2 (i.e., S1 ≤ S2).

[0025] Here, the diameter dimension of the rib 25 is determined based on predetermined conditions. That is, in the cross section orthogonal to the movement axis C of the rib 25, when the difference between the inner diameter cross-sectional area A1 of the first valve chamber 11 and the outer diameter cross-sectional area A2 of the rib 25 is defined as the cross-sectional area D1, and the difference between the inner diameter cross-sectional area A1 of the first valve chamber 11 and the outer diameter cross-sectional area A3 of the valve body 3a is defined as the cross-sectional area D2, the cross-sectional area D1 and the cross-sectional area D2 satisfy D1 < D2, the ratio (D2 / D1) is 2 or more, and the cross-sectional area D1 is such that D3 ≤ D1, where D3 is the cross-sectional area that is the difference between the inner diameter cross-sectional area A4 of the connection flow path 13 and the outer diameter cross-sectional area A5 of the shaft 4a inserted into the connection flow path 13. The diameter dimension of the rib 25 is determined.

[0026] Next, the operation and effect of the fluid control valve (constant pressure valve) 1A having the above configuration will be described. In the fluid control valve 1A, the valve body 3a of the first diaphragm 3 is pushed upward by the biasing force of the biasing spring 6c and pressed against the valve seat 15. From this state, when the working fluid is supplied into the pressure chamber 5b through the working fluid supply port 5a, the shaft 4a of the second diaphragm 4 is pushed downward and abuts against the valve body 3a. Further, when the valve body 3a is pressed downward by the shaft 4a against the biasing force of the biasing spring 6c, the valve body 3a is separated from the valve seat 15 and the fluid passes from the first valve chamber 11 to the second valve chamber 12 (see FIG. 1). The flow rate can be set to an arbitrary value by adjusting the working fluid supplied into the pressure chamber 5b and changing the gap S3 between the valve body 3a and the valve seat 15.

[0027] When the flow rate of the fluid is at a set value, the valve element 3a comes to rest in a position where three forces are balanced: the biasing force of the biasing spring 6c, the force pushing up the lower surface of the second diaphragm 4 due to the pressure of the fluid, and the force pushing down the upper surface of the second diaphragm 4 due to the pressure of the working fluid. Strictly speaking, the lower surface of the valve element 3a and the membrane portion 3b of the first diaphragm 3 are subjected to pressure from the fluid in the first valve chamber 11, but their pressure-receiving areas are designed to be approximately equal, so the forces are essentially canceled out.

[0028] In this state, if the upstream fluid pressure increases, the pressure in the second valve chamber 12 also increases instantaneously. As a result, the force acting on the bottom surface of the second diaphragm 4 from the working fluid becomes greater than the force acting on the top surface of the second diaphragm 4 from the fluid, causing the second diaphragm 4 to move upward. As a result, the valve disc 3a also moves upward together with the shaft 4a, reducing the opening area between the valve seat 15 and the valve disc 3a and decreasing the pressure in the second valve chamber 12. Eventually, the valve disc 3a comes to rest at a position where the three forces mentioned above are balanced, and the fluid pressure in the second valve chamber 12 returns to approximately the same pressure as before the upstream fluid pressure increased.

[0029] On the other hand, when the pressure on the upstream side decreases, the pressure in the second valve chamber 12 also decreases instantaneously. As a result, the force acting on the bottom surface of the second diaphragm 4 from the working fluid becomes smaller than the force acting on the top surface of the second diaphragm 4 from the fluid, and the second diaphragm 4 moves downward. As a result, the valve disc 3a also moves downward together with the shaft 4a, increasing the opening area between the valve seat 15 and the valve disc 3a and increasing the pressure in the second valve chamber 12. Eventually, the valve disc 3a comes to rest at a position where the above three forces are balanced, and the fluid pressure in the second valve chamber 12 returns to approximately the same pressure as before the upstream fluid pressure decreased.

[0030] As described above, even if the fluid pressure upstream of the fluid control valve 1A fluctuates, the fluid pressure in the second valve chamber 12 changes very little. Therefore, if there is no change in the pressure loss in the piping downstream of the fluid control valve 1A, the flow rate can be maintained constant. Furthermore, since the fluid pressure in the second valve chamber 12 can be adjusted by the pressure of the working fluid in the pressurizing chamber 5b, the flow rate can also be adjusted by the working fluid. Furthermore, if no working fluid is supplied to the pressurizing chamber 5b, the movable body 6b is pushed up by the biasing force of the biasing spring 6c, and the valve element 3a, which is linked to the movable body 6b via the stem 6d, is also pushed up. Therefore, the valve element 3a abuts against the valve seat 15, blocking the flow of fluid.

[0031] This fluid control valve 1A is used in devices that transfer various fluids in various industrial fields, such as semiconductor manufacturing, chemical plants, and food processing. When switching the fluid to be used and starting up the device, the ribs 25 of the fluid control valve 1A guide a portion of the fluid flowing from the inlet flow path 8 into the first valve chamber 11 so that it flows diagonally downward, as shown by the dashed arrow in FIG. 4 . Once guided downward by the ribs 25 and into the first valve chamber 11, the fluid's flow direction is corrected by the gap S1, and the fluid's direction of travel is straightened vertically upward. This prevents the fluid from flowing unevenly around the axis of movement C, and it flows sequentially through the connecting flow path 13 and the second valve chamber 12 before being sent to the outlet flow path 9. This makes it difficult for the fluid to take a shortcut from the inlet flow path 8 to the outlet flow path 9, ensuring a sufficient flow rate on the side of the second valve chamber 12 opposite the outlet flow path 9.

[0032] Here, when the results of the fluid simulation of the present fluid control valve 1A (see FIG. 5(a)) are compared with the results of the fluid simulation of the conventional fluid control valve 101 (see FIG. 14) (see FIG. 5(b)), it was found that the present fluid control valve 1A has an increased fluid flow at the back side of the outlet flow path 9 of the second valve chamber 12 compared to the conventional fluid control valve 101, and the fluid replacement time is reduced by approximately 17%.

[0033] As described above, according to the fluid control valve 1A of the present embodiment, ribs 25 are provided on the outer peripheral surface of the valve body 3a, and a gap S1 is formed between the outer peripheral surface of the ribs 25 and the inner peripheral surface of the first valve chamber 11. Thereby, when starting up the device by switching the working fluid, the bias of the flow rate around the moving axis C is suppressed by the flow rectifying action of the ribs 25 and the gap S1, so that a sufficient flow rate of fluid can flow to the side opposite to the outlet passage 9 of the second valve chamber 12 (the back side), promoting the replaceability of the fluid. Also, it is difficult for a fluid stagnation part to occur on the side opposite to the outlet passage 9 of the second valve chamber 12, and it is possible to suppress the occurrence of problems due to dirt that is likely to be included in the stagnation part at the fluid supply destination. Furthermore, the thickness of the part including the valve seat 15 of the valve body 2 can be ensured, maintaining the durability of the valve seat 15.

[0034] Also, in the present embodiment, the ribs 25 are formed in an annular shape over the entire circumference of the outer peripheral surface of the valve body 3a. Thereby, the flow rectifying action of the ribs 25 and the gap S1 can be more effectively exerted. In particular, in the present embodiment, since relatively thin flange-shaped ribs 25 are employed, the amount of material used for the ribs 25 and thus the first diaphragm 3 including the valve body 3a can be suppressed.

[0035] Also, in the present embodiment, in the cross section orthogonal to the moving axis C of the ribs 25, when the difference between the inner diameter cross-sectional area A1 of the first valve chamber 11 and the outer diameter cross-sectional area A2 of the ribs 25 is defined as the cross-sectional area D1, and the difference between the inner diameter cross-sectional area A1 of the first valve chamber 11 and the outer diameter cross-sectional area A3 of the valve body 3a is defined as the cross-sectional area D2, the cross-sectional area D1 and the cross-sectional area D2 satisfy D1 < D2, the ratio (D2 / D1) satisfies D2 / D1 ≧ 2, and the cross-sectional area D1 is such that D3 ≦ D1, where D3 is the cross-sectional area that is the difference between the inner diameter cross-sectional area A4 of the connection passage 13 and the outer diameter cross-sectional area A5 of the shaft 4a inserted into the connection passage 13. Thereby, the flow rectifying action of the ribs 25 and the gap S1 can be more effectively exerted.

[0036] Furthermore, in this embodiment, the second diaphragm 4 has a shaft 4a that is inserted into the connecting flow path 13, and the gap S1 between the outer peripheral surface of the rib 25 and the inner peripheral surface of the first valve chamber 11 is equal to or smaller than the gap S2 between the outer peripheral surface of the shaft 4a and the inner peripheral surface of the connecting flow path 13. This allows the rib 25 and the gap S1 to more effectively rectify the fluid flow.

[0037] Furthermore, in this embodiment, the length L of the rib 25 in the direction perpendicular to the movement axis C is 1 mm or more, which allows the rib 25 and the gap S1 to more effectively rectify the fluid flow.

[0038] <Embodiment 2> Next, a fluid control valve 1B according to a second embodiment will be described with reference to FIGS. 6 to 8. Parts having substantially the same configuration as those in the above-described fluid control valve 1A will be assigned the same reference numerals and detailed description thereof will be omitted.

[0039] 6, the fluid control valve 1B according to this embodiment includes a valve body 2, a first diaphragm 3 and a second diaphragm 4 that are provided in the valve body 2 and move the valve element 3a toward and away from the valve seat 15 in the direction of the movement axis C. The fluid control valve 1B further includes a plate 5 attached to the upper part of the valve body 2, and a pressurizing unit 6 attached to the lower part of the valve body 2.

[0040] As shown in FIGS. 7 and 8, the outer peripheral surface of the valve disc 3a is provided with ribs 25 that guide the flow direction of a portion of the fluid flowing from the inlet flow path 8 into the first valve chamber 11. The valve body 2 also has an annular valve chamber forming surface 18 that defines the second valve chamber 12. The valve chamber forming surface 18 is formed by the bottom surface 12b of the second valve chamber 12. The valve chamber forming surface 18 is a conical surface centered on the movement axis C, and in a cross section along the movement axis C of the valve body 2, it is inclined at a predetermined inclination angle θ1 (e.g., 5 degrees) with respect to a direction perpendicular to the movement axis C. However, the magnitude of this inclination angle θ1 is not particularly limited, and from the viewpoint of the formability of the second valve chamber 12 as a constant pressure valve, it is preferably 3 to 13 degrees (more preferably 3 to 6 degrees, and even more preferably 4 to 5 degrees).

[0041] A recess 20 is formed on the valve chamber forming surface 18 on the opposite side of the outlet flow path 9 from the outlet flow path 9 (on the back side) of the second valve chamber 12 to suppress an increase in fluid pressure. The recess 20 is located in the valve body 2, away from the valve seat 15 (i.e., in the centrifugal direction about the movement axis C). Specifically, the recess 20 is located closer to the outer periphery of the valve chamber forming surface 18. The distance L1 between the recess 20 and the valve seat 15 in the direction perpendicular to the movement axis C is 6 mm. However, the size of this distance L1 is not particularly limited, and is preferably 5 to 10 mm (more preferably 5 to 8 mm, and even more preferably 5 to 7 mm) from the viewpoints of ensuring the thickness of the portion of the valve body 2 including the valve seat 15 and preventing the valve body 2 from becoming too large in the radial direction. The vertical width L2 of the recess 20 is 5 mm. However, the size of this vertical width L2 is not particularly limited, and from the viewpoint of suppressing pressure rise on the opposite side of the outlet flow path 9 of the second valve chamber 12, it is preferably 3 to 7 mm (more preferably 4 to 6 mm, and even more preferably 4 to 5 mm).

[0042] The recess 20 is formed in a plane fan shape. The angular range θ2 of the recess 20 in the circumferential direction centered on the movement axis C is 50 degrees. However, this angular range θ2 is not particularly limited, and from the viewpoint of suppressing pressure increases on the side of the second valve chamber 12 opposite the outlet flow path 9, it is preferable that the angular range θ2 be 25 to 75 degrees (more preferably 30 to 70 degrees, and even more preferably 35 to 65 degrees). The recess 20 has a bottom surface 20a and upright wall surfaces 20b rising from the left and right side edges of the bottom surface 20a. The bottom surface 20a is formed by a plane perpendicular to the movement axis C. The inner peripheral edge of the bottom surface 20a intersects with and is directly connected to the valve chamber forming surface 18. The outer peripheral edge of the bottom surface 20a is connected to the inner peripheral surface 12a of the second valve chamber 12 via a connecting surface 20c having an arc-shaped longitudinal cross section.

[0043] Next, the effects of the fluid control valve (constant pressure valve) 1B configured as described above will be described. This fluid control valve 1B is used in devices that transfer various fluids in various industrial fields, such as semiconductor manufacturing, chemical plants, and food processing. When switching the fluid to be used and starting up the device, the ribs 25 in the fluid control valve 1B guide a portion of the fluid flowing from the inlet flow path 8 into the first valve chamber 11 so that it flows diagonally downward. After being guided downward by the ribs 25 and flowing into the first valve chamber 11, the flow direction is corrected by the gap S1, and the fluid is rectified to a vertically upward flow direction. As a result, the fluid flows sequentially through the connecting flow path 13 and the second valve chamber 12 and is sent to the outlet flow path 9 without any deviation in flow rate around the movement axis C. Furthermore, the recess 20 makes the space on the opposite side of the second valve chamber 12 from the outlet flow path 9 larger than the other spaces, thereby suppressing a rise in fluid pressure on the opposite side of the second valve chamber 12 from the outlet flow path 9. Therefore, the fluid is less likely to take a shortcut from the inlet flow path 8 side to the outlet flow path 9 side, and a sufficient amount of fluid flows on the side of the second valve chest 12 opposite the outlet flow path 9 side.

[0044] As described above, the fluid control valve 1B of this embodiment has substantially the same effects as the above-described fluid control valve 1A, and has a recess (groove) 20 formed at a position away from the valve seat (seal portion) 15 on the side of the valve chest forming surface 18 opposite the outlet flow path 9 across the movement axis C. As a result, when switching the working fluid and starting up the device, the rib 25 and the gap S1 rectify the fluid to prevent unevenness in the flow rate around the movement axis C, and the recess 20 also prevents an increase in fluid pressure on the side of the second valve chest 12 opposite the outlet flow path 9 (back side). As a result, a sufficient flow rate of fluid can be allowed to flow on the side of the second valve chest 12 opposite the outlet flow path 9, facilitating fluid replacement.

[0045] Furthermore, in this embodiment, the recessed portion 20 is disposed closer to the outer periphery of the valve chamber forming surface 18. This makes it possible to more effectively suppress the increase in fluid pressure on the side opposite the outlet flow path 9 of the second valve chamber 12.

[0046] In this embodiment, the distance L1 between the recess 20 and the valve seat 15 in the direction perpendicular to the movement axis C is 6 mm. This ensures a sufficient thickness for the portion of the valve body 2 including the valve seat 15, and also prevents the valve body 2 from becoming too large in the radial direction.

[0047] In this embodiment, the recess 20 is formed so that the angular range θ2 in the circumferential direction about the movement axis C is 50 degrees. This makes it possible to more effectively suppress the increase in fluid pressure on the side of the second valve chamber 12 opposite the outlet flow path 9.

[0048] In this embodiment, the bottom surface 20a of the recessed portion 20 is formed as a flat surface, which makes it possible to more effectively prevent the occurrence of a stagnant portion of the fluid on the side of the second valve chamber 12 opposite the outlet flow path 9.

[0049] Furthermore, in this embodiment, the inner peripheral edge of the bottom surface 20a of the recessed portion 20 intersects with and is directly connected to the valve chamber forming surface 18. This makes it possible to more effectively prevent the occurrence of stagnation of fluid on the side of the second valve chamber 12 opposite the outlet flow path 9.

[0050] Furthermore, in this embodiment, the outer peripheral edge of the bottom surface 20a of the recessed portion 20 is connected to the inner peripheral surface of the second valve chamber 12 via a connecting surface 20c that has an arc-shaped longitudinal cross section. This makes it possible to more effectively prevent the occurrence of stagnation of fluid on the side of the second valve chamber 12 opposite the outlet flow path 9.

[0051] The present invention is not limited to the above-described first and second embodiments, and various modifications can be made within the scope of the present invention based on the purpose and application. That is, in the above-described first and second embodiments, the rib 25 is provided so as to form a step on the upper surface of the valve body 3a, but the present invention is not limited to this. For example, as shown in Figures 9 to 11, a configuration in which the rib 25 is provided so that the upper surface of the valve body 3a and the upper surface of the rib 25 are flush with each other may be adopted.

[0052] Furthermore, in the above-described first and second embodiments, when the gap S3 between the valve body 3 a and the valve seat 15 is at a predetermined set value, the rib 25 is positioned above the opening of the inlet fluid 8 into the first valve chamber 11. However, the present invention is not limited to this. For example, as shown in FIG. 10, when the gap S3 between the valve body 3 a and the valve seat 15 is at a predetermined set value, a part of the opening of the inlet flow path 8 into the first valve chamber 11 (for example, above the center of the opening of the inlet flow path 8) and the outer peripheral surface of the rib 25 may face each other.

[0053] In the above-described first and second embodiments, the annular rib 25 is provided around the entire outer periphery of the valve body 3a, but the present invention is not limited to this. For example, as shown in Fig. 11, the rib 25 may be provided only on the outer periphery of the valve body 3a on the inlet flow path 8 side. In this embodiment, from the viewpoint of the fluid guiding ability of the rib 25, it is preferable that the width W1 of the rib 25 is larger than the width W2 of the inlet flow path 8.

[0054] Furthermore, in the above-described second embodiment, a configuration in which one recess 20 is provided in the valve chamber forming surface 18 of the valve body 2 is exemplified, but this is not limiting, and for example, as shown in Fig. 12(a), a configuration in which multiple (two in the figure) recesses 20 are provided in the valve chamber forming surface 18 of the valve body 2 may be employed. In this configuration, multiple recesses 20 can be arranged in the circumferential direction around the movement axis C.

[0055] Furthermore, in the above-described second embodiment, the recessed portion 20 is disposed on the outer periphery side of the valve chamber forming surface 18, but this is not limited thereto. For example, as shown in FIG. 12(b), a recessed portion 20 disposed in the radially middle portion of the valve chamber forming surface 18 may be employed.

[0056] In addition, in the above-mentioned embodiment 2, an example of the recessed portion 20 formed in a plane fan shape was given, but this is not limited to this, and for example, as shown in Figure 12(c), a recessed portion 20 formed in a plane shape of a polygon such as an approximately square or approximately triangular shape, an approximately elliptical shape, or an approximately circular shape may be used.

[0057] In addition, in the above-described second embodiment, the recessed portion 20 has one bottom surface 20a, but this is not limiting, and for example, a recessed portion 20 having a plurality of bottom surfaces 20a in which adjacent bottom surfaces 20a intersect with each other in the circumferential direction may be employed. In this embodiment, for example, a recessed portion 20 having a substantially V-shaped groove shape can be formed.

[0058] Furthermore, in the above-described second embodiment, the recessed portion 20 has a bottom surface 20a that is flat, but this is not limited to this, and a recessed portion 20 having a bottom surface 20a that is, for example, a curved surface, a hemispherical surface, or the like may also be used.

[0059] Furthermore, in the above-described second embodiment, the recessed portion 20 has a bottom surface 20a that is a plane perpendicular to the movement axis C. However, the present invention is not limited to this. For example, as shown in Fig. 13, a recessed portion 20 having a bottom surface 20a that is a plane that is inclined with respect to the plane perpendicular to the movement axis C may be employed. In this embodiment, the inclination angle θ3 of the bottom surface 20a of the recessed portion 20 with respect to the horizontal is smaller than the inclination angle θ1 of the valve-chamber-forming surface 18 with respect to the horizontal. [Industrial Applicability]

[0060] The present invention is widely used as a technology relating to a fluid control valve that can be applied to, for example, a constant pressure valve, a back pressure valve, an on-off valve, a suck-back valve, etc. [Explanation of symbols]

[0061] 1A, 1B: Fluid control valve 2: Valve body 3; First diaphragm 4; Second diaphragm 8; Inlet flow path 9; Outlet flow path 11;1st valve chamber 12;2nd valve chamber 13; Connecting passage 15; Valve seat 3a; valve body 25; rib A1: Inner diameter cross-sectional area of ​​the first valve chamber A2: Outer diameter cross-sectional area of ​​the rib A3: Outer diameter cross-sectional area of ​​the valve body A4: Inner diameter cross-sectional area of ​​the connecting flow path A5: Shaft outer diameter cross-sectional area C: Moving axis D1: Cross-sectional area (difference between A1 and A2) D2: Cross-sectional area (difference between A1 and A3) D3: Breakage area (difference between A4 and A5) L: Rib length S1: Gap between the rib and the first valve chamber S2: Gap between the shaft and the connecting passage

Claims

1. a valve body having a first valve chamber communicating with an inlet flow path, a second valve chamber communicating with an outlet flow path, and a connecting flow path connecting the first valve chamber and the second valve chamber; a first diaphragm attached to the valve body so as to face the first valve chamber; a second diaphragm attached to the valve body so as to face the second valve chamber; Equipped with a valve seat is provided in the valve body at a communicating portion between the first valve chamber and the connecting flow path, The first diaphragm is provided with a valve body that moves toward and away from the valve seat in a moving axial direction, a rib is provided on at least the inlet flow path side of the outer circumferential surface of the valve body, A fluid control valve characterized in that a gap (S1) is formed between an outer peripheral surface of the rib and an inner peripheral surface of the first valve chamber.

2. 2. The fluid control valve according to claim 1, wherein the rib is formed in an annular shape over the entire outer periphery of the valve body.

3. 2. The fluid control valve according to claim 1, wherein, in a transverse cross section perpendicular to the movement axis of the rib, when a difference between an inner diameter cross-sectional area (A1) of the first valve chamber and an outer diameter cross-sectional area (A2) of the rib is defined as a cross-sectional area (D1), and a difference between the inner diameter cross-sectional area (A1) of the first valve chamber and an outer diameter cross-sectional area (A3) of the valve disc is defined as a cross-sectional area (D2), the cross-sectional area (D1) and the cross-sectional area (D2) satisfy D1<D2, a ratio (D2 / D1) thereof satisfies D2 / D1≧2, and the cross-sectional area (D1) satisfies D3≦D1 for a cross-sectional area (D3) which is a difference between an inner diameter cross-sectional area (A4) of the connecting flow path and an outer diameter cross-sectional area (A5) of a shaft inserted into the connecting flow path.

4. the second diaphragm has a shaft inserted into the connecting flow passage; 2. The fluid control valve according to claim 1, wherein the gap (S1) between the outer peripheral surface of the rib and the inner peripheral surface of the first valve chamber is equal to or smaller than the gap (S2) between the outer peripheral surface of the shaft and the inner peripheral surface of the connecting flow path.

5. 2. The fluid control valve according to claim 1, wherein the length (L) of the rib in a direction perpendicular to the axis of movement is 1 mm or more.

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