Fluid control valve and fluid control device

Abstract

To reduce seat leakage while increasing a flow rate.SOLUTION: A fluid control valve 3 for controlling a fluid from an upstream side flow passage R1 to let the fluid flow out to a downstream side flow passage R2, comprises an orifice 31 having a valve seat surface 31s, and a valve element 32 having a seating surface 32s for seating on the valve seat surface 31s. The orifice 31 has an annular groove M1 formed in the valve seat surface 31s, and an internal flow path L1 that communicates with an upstream flow path R1 and is opened in the annular groove M1. The internal flow path L1 is opened on the same plane as the valve seat surface 31s and extends outward of the annular groove M1 in plan view.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a fluid control valve and a fluid control device. [Background technology]

[0002] Conventional fluid control valves have been considered to have a configuration in which a plurality of grooves are formed in the valve seat surface of an orifice, and internal flow paths are opened to the bottom or side of the grooves, as shown in Patent Documents 1 and 2. Specifically, the grooves in which the inlet is formed and the grooves in which the outlet is formed are different from each other, and the valve seat surface is formed between the grooves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-230159 [Patent Document 2] Patent No. 5735331 Summary of the Invention [Problem to be solved by the invention]

[0004] In all of the above-mentioned fluid control valves, the internal flow path is opened at the bottom or side of the groove, and in order to achieve a larger flow rate, it is conceivable to increase the width of the groove to increase the opening diameter of the inlet and outlet. However, if the groove width is increased, the width of the valve seat formed between the grooves becomes smaller, which may increase the amount of seat leakage in the fully closed state.

[0005] On the other hand, in order to reduce the amount of seat leakage in the above-mentioned fluid control valve in the fully closed state, it is conceivable to increase the width of the valve seat surface formed between the grooves. However, increasing the width of the valve seat surface reduces the width of the groove, which in turn reduces the opening diameters of the inlet and outlet formed on the bottom surface of the groove, which may hinder a large flow rate. Incidentally, Patent Documents 1 and 2 do not take the amount of seat leakage into consideration at all.

[0006] The present invention has been made in view of the above-mentioned problems, and its main object is to reduce seat leaks while increasing the flow rate. [Means for solving the problem]

[0007] That is, the fluid control valve according to the present invention is a fluid control valve that controls a fluid from an upstream flow path to flow into a downstream flow path, and is characterized in that it comprises an orifice having a valve seat surface, and a valve body having a seat surface that seats on the valve seat surface, the orifice having an annular groove formed on the valve seat surface, and an internal flow path that communicates with the upstream flow path or the downstream flow path and also communicates with the annular groove, the internal flow path opening on the same plane as the valve seat surface, and the opening extending outward beyond the annular groove in a plan view.

[0008] In this fluid control valve, the internal flow path opens flush with the valve seat surface and extends further outward than the annular groove in a plan view, thereby improving the maximum flow rate while reducing seat leakage. Specifically, in the configurations in which the internal flow path opens on the bottom or side of the annular groove, as in Patent Documents 1 and 2, the size of the opening on the valve seat surface is limited by the groove width of the annular groove. However, in the present invention, the opening size of the internal flow path on the valve seat surface is not limited by the groove width of the annular groove. This improves the maximum flow rate. Furthermore, the groove width of the annular groove can be narrowed regardless of the opening size of the internal flow path. This allows the area of ​​the valve seat surface to be increased, thereby reducing seat leakage. Furthermore, increasing the area of ​​the valve seat surface reduces stress generated between the valve seat surface and the seat surface in a fully closed state, thereby reducing damage to the seat surface or the valve seat surface.

[0009] As a specific embodiment of the internal flow path and the annular groove, the internal flow path may have an upstream internal flow path communicating with the upstream flow path and a downstream internal flow path communicating with the downstream flow path, and the annular groove may have an upstream annular groove communicating with the upstream internal flow path and a downstream annular groove communicating with the downstream internal flow path. In this configuration, it is desirable that the upstream internal flow passage opens onto the same plane as the valve seat surface, and that the opening extends outward beyond the upstream annular groove in a plan view. It is also preferable that the downstream internal flow passage opens on the same plane as the valve seat surface, and that the opening extends outward beyond the downstream annular groove in a plan view.

[0010] As a specific embodiment of the annular grooves, it is desirable that the upstream annular groove and the downstream annular groove are formed in the valve seat surface in a substantially concentric shape. With this configuration, the fluid flowing out of the upstream annular groove flows into the adjacent downstream annular grooves evenly in the circumferential direction, thereby reducing pressure loss and increasing the flow rate.

[0011] It is desirable that the upstream annular groove and the downstream annular groove are alternately formed on the valve seat surface. With this configuration, the distance between the opening (inlet) of the upstream internal flow path and the opening (outlet) of the downstream internal flow path can be made as short as possible, reducing pressure loss and achieving a large flow rate.

[0012] As a specific embodiment for achieving a large flow rate, it is desirable that a plurality of the upstream internal flow paths are connected to the upstream annular groove, and a plurality of the downstream internal flow paths are connected to the downstream annular groove.

[0013] In order to facilitate the manufacture of the fluid control valve and to effectively utilize the area of ​​the valve seat surface, it is desirable that the opening of the upstream internal flow path and the opening of the downstream internal flow path are formed so as to be offset from each other in the circumferential direction when viewed in plan.

[0014] It is desirable that the upstream annular groove and the downstream annular groove have different depths. With this configuration, the upstream internal flow path and the downstream internal flow path can be formed smoothly inside the orifice so as not to interfere with each other.

[0015] In a specific embodiment of the orifice, it is desirable that the shallower of the upstream annular groove and the downstream annular groove is connected to an internal flow passage formed by penetrating from the undersurface on the opposite side to the valve seat surface. For example, if the upstream annular groove is shallower than the downstream annular groove, the upstream internal flow passage is formed by penetrating from the undersurface on the opposite side to the valve seat surface.

[0016] In a specific embodiment of the orifice, it is desirable that the deeper of the upstream annular groove and the downstream annular groove is connected to a linear internal flow passage formed from a side surface other than the valve seat surface and the lower surface opposite to the valve seat surface. For example, when the downstream annular groove is deeper than the upstream annular groove, the downstream internal flow passage is a linear flow passage formed from a side surface other than the valve seat surface and the lower surface.

[0017] A fluid control device including the above-described fluid control valve is also one aspect of the present invention. Specifically, this fluid control device is characterized by including the above-described fluid control valve, a flow rate measuring unit that measures the flow rate of a flow path, and a valve control unit that controls the fluid control valve based on the measured value measured by the flow rate measuring unit. [Effects of the Invention]

[0018] According to the present invention as described above, it is possible to increase the flow rate while reducing seat leaks. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram showing the configuration of a fluid control device according to an embodiment of the present invention; [Figure 2] FIG. 2 is an enlarged cross-sectional view showing the configuration of the fluid control valve of the embodiment. [Figure 3] FIG. 2 is a perspective view of an orifice according to the embodiment. [Figure 4] FIG. 2 is a plan view of the orifice of the embodiment. [Figure 5] FIG. 2 is a cross-sectional view taken along line AA of the embodiment. [Figure 6] FIG. 5 is a cross-sectional view taken along line BB of the embodiment. [Figure 7] 1A is a plan view of the embodiment in which the opening of the upstream internal flow path and the upstream annular groove are hatched, and FIG. 1B is a plan view of the embodiment in which the opening of the downstream internal flow path and the downstream annular groove are hatched. [Figure 8] 10 is a graph showing the results of a comparison between the present embodiment and a conventional example with respect to the maximum flow rate in a fully open state. [Figure 9] 10 is a graph showing the results of a comparison between the present embodiment and a conventional example regarding the amount of seat leakage in a fully closed state. DETAILED DESCRIPTION OF THE INVENTION

[0020] A fluid control device according to an embodiment of the present invention will be described below with reference to the drawings. Note that in all of the drawings shown below, parts are appropriately omitted or exaggerated for clarity. Identical components are assigned the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0021] <Device configuration> The fluid control device 100 of this embodiment is a so-called mass flow controller, and is used to control the flow rate of gas supplied to a chamber in which a semiconductor manufacturing process is performed, for example. Note that the fluid control device 100 may control not only gas but also liquid.

[0022] Specifically, as shown in FIG. 1, the fluid control device 100 includes a flow path block 2 having a flow path R formed therein, a fluid control valve 3 for controlling the gas in the flow path R, a flow sensor 4 for measuring the flow rate of the flow path R, and a valve control unit 5 for controlling the fluid control valve 3 based on the measurement value measured by the flow sensor 4.

[0023] The flow path block 2 is formed with an accommodating recess 21 in which the fluid control valve 3 is attached. The accommodating recess 21 is formed on one surface (the upper surface in FIG. 1) of the flow path block 2. An upstream flow path R1 is connected to the bottom surface of the accommodating recess 21, and a downstream flow path R2 is connected to the inner circumferential surface of the accommodating recess 21. In other words, the flow path R formed in the flow path block 2 is divided by the accommodating recess 21 into the upstream flow path R1 and the downstream flow path R2.

[0024] A gas inlet port (not shown) is provided at the upstream end of the upstream flow path R1, and a gas outlet port (not shown) is provided at the downstream end of the downstream flow path R2.

[0025] The fluid control valve 3 is a so-called normally open piezo valve, and the opening degree thereof is controlled by an applied voltage. The fluid control valve 3 may also be a so-called normally closed type.

[0026] Specifically, as shown in FIG. 1, the fluid control valve 3 includes an orifice (valve seat member) 31 having a valve seat surface 31s, a valve body 32 having a seat surface 32s that seats on the valve seat surface 31s, and a drive unit 33 that drives the valve body 32.

[0027] 2, the orifice 31 has a valve seat surface 31s and internal flow paths L1 and L2 that open to the valve seat surface 31s. The orifice 31 is accommodated in the accommodation recess 21 so that the valve seat surface 31s faces the opening of the accommodation recess 21. A seal member 34 is provided between a lower surface 31t of the orifice 31 opposite the valve seat surface 31s and the bottom surface of the accommodation recess 21 so as to surround the opening of the upstream flow path R1. In addition, a flow path that communicates with the downstream flow path R2 is formed between an outer peripheral surface 31u of the orifice 31 and an inner peripheral surface of the accommodation recess 21. Details of the orifice 31 will be described later.

[0028] The valve element 32 has a flat seating surface 32s that seats on the valve seat surface 31s. The valve element 32 is provided movably facing the valve seat surface 31s of the orifice 31. The valve element 32 is also biased in the valve opening direction (upward) by an elastic member 35 provided on a support member 332c, which will be described later.

[0029] The drive unit 33 includes an actuator 331 and a plunger mechanism 332 that is displaced by the actuator 331 to drive the valve element 32. The plunger mechanism 332 of this embodiment uses a plunger portion 332a that is displaced by the extension of the actuator 331, and a diaphragm 332b that supports the plunger portion 332a so that it can be displaced. The diaphragm 332b and a support member 332c that is integrally formed on the outer periphery of the diaphragm 332b close the opening of the accommodation recess 21 via a seal member 36. The valve element 32 is accommodated in a space formed among the diaphragm 332b, the support member 332c, and the orifice 31.

[0030] When a predetermined voltage is applied to the actuator 331, the actuator 331 extends, and the plunger portion 332a of the plunger mechanism 332 presses the valve element 32 in the valve closing direction, resulting in a valve opening degree corresponding to the applied voltage. On the other hand, when no voltage is applied to the actuator 331, the elastic force of the elastic member 35 causes the valve element 32 to be in a fully open state.

[0031] The flow sensor 4 is a pressure type and includes a laminar flow element 41 provided in the flow path R, a first pressure sensor 42 provided so as to be able to measure the pressure upstream of the laminar flow element 41, a second pressure sensor 43 provided so as to be able to measure the pressure downstream of the laminar flow element 41, and a flow rate calculation unit 44 that calculates the flow rate of the fluid flowing through the flow path R based on the first pressure and second pressure measured by the first pressure sensor 42 and the second pressure sensor 43. This flow rate sensor 4 is provided in the flow path R on the upstream side or downstream side of the fluid control valve 3. Note that a sonic nozzle or the like may be used as the fluid resistance 41 instead of the laminar flow element.

[0032] The valve control unit 5 controls the fluid control valve 3 based on the flow rate measured by the flow sensor 4. This valve control unit 5 is a computer equipped with a CPU, memory, A / D converter, D / A converter, and various input / output means, and controls the fluid control valve 3 by executing a fluid control program stored in the memory and working together with the CPU and peripheral devices.

[0033] The valve control unit 5 controls the aperture of the fluid control valve 3 based on a command flow rate input from outside and a measured flow rate measured by the flow sensor 4. Specifically, the valve control unit 5 controls the aperture of the fluid control valve 3 so as to reduce the deviation between the command flow rate and the measured flow rate. The valve control unit 5 of this embodiment performs a PID calculation on the deviation between the command flow rate and the measured flow rate, and outputs a command voltage corresponding to the result to the drive circuit of the drive unit 33. The drive circuit applies a voltage corresponding to the input command voltage to the piezo stack 331.

[0034] <Specific configuration of the orifice 31> The orifice 31 of this embodiment has a configuration that allows for a large flow rate and reduces seat leakage in a fully closed state.

[0035] 2 to 7, the orifice 31 is generally disk-shaped and has a valve seat surface 31s on one surface (upper surface) thereof. The orifice 31 has annular grooves M1, M2 formed in the valve seat surface 31s, and internal flow paths L1, L2 that communicate with the upstream flow path R1 or the downstream flow path R2 and that open at the annular grooves M1, M2.

[0036] 2 to 7, the orifice 31 has an upstream internal flow passage L1 communicating with the upstream flow passage R1 and a downstream internal flow passage L2 communicating with the downstream flow passage R2. The orifice 31 also has an upstream annular groove M1 into which the upstream internal flow passage L1 opens and a downstream annular groove M2 into which the downstream internal flow passage L2 opens.

[0037] 6, the upstream internal flow path L1 is a straight line formed from the lower surface 31t opposite the valve seat surface 31s through the orifice 31. Although the upstream internal flow path L1 in this embodiment has a uniform cross-sectional shape, the flow path shape does not have to be the same cross-sectional shape.

[0038] 5 and 6, the downstream internal flow path L2 is a straight line extending radially inward from a side surface (here, the outer peripheral surface 31u) other than the valve seat surface 31s and the lower surface 31t. Although the downstream internal flow path L2 in this embodiment has a uniform cross-sectional shape, the flow path shape does not have to be a uniform cross-sectional shape.

[0039] As shown in FIGS. 3, 4, and 6, the upstream annular groove M1 and the downstream annular groove M2 each have an annular shape in a plan view. In this embodiment, the upstream annular groove M1 is a partial annular groove formed intermittently in the circumferential direction, and together with virtual annular grooves formed by extending these partial annular grooves, the upstream annular groove M1 and the downstream annular groove M2 each have a groove shape with the same width in the circumferential direction. The upstream annular groove M1 and the downstream annular groove M2 are formed in a substantially concentric shape on the valve seat surface 31s. The upstream annular groove M1 and the downstream annular groove M2 are alternately formed on the valve seat surface 31s. In this embodiment, from the radially inner side, two downstream annular grooves M2, one upstream annular groove M1, and two downstream annular grooves M2 are formed in this order. The annular grooves may have an annular shape other than an annular shape in a plan view, such as an elliptical annular shape or a rectangular annular shape.

[0040] The upstream annular groove M1 and the downstream annular groove M2 may be alternately formed one by one from the radially inner side.

[0041] As shown in FIGS. 3 and 5 to 7, the upstream internal flow passage L1 opens on the same plane as the valve seat surface 31s, and as shown in FIG. 4, the opening extends outward beyond the upstream annular groove M1 in plan view. That is, the edge of the opening L11 of the upstream internal flow passage L1 protrudes outward beyond the imaginary annular groove of the upstream annular groove M1 in plan view. More specifically, the opening L11 of the upstream internal flow passage L1 has a circular shape in plan view relative to the valve seat surface 31s, and its opening diameter is larger than the radial groove width of the upstream annular groove M1. That is, the opening L11 of the upstream internal flow passage L1 protrudes radially outward from the outer side surface of the upstream annular groove M1 and protrudes radially inward from the inner side surface of the upstream annular groove M1. In addition, the upstream internal flow passage L1 also opens to the center of the valve seat surface 31s, which is surrounded by the innermost downstream annular groove M2.

[0042] 4, the valve seat surface 31s between the upstream annular groove M1 and the adjacent downstream annular groove M2 on the outside has a generally circular ring shape in plan view, but the opening L11 of the upstream internal flow path L1 causes a portion of its inner periphery to be cut out in a partially arcuate shape. Also, the valve seat surface 31s between the upstream annular groove M1 and the adjacent downstream annular groove M2 on the inside has a generally circular ring shape in plan view, but the opening L11 of the upstream internal flow path L1 causes a portion of its outer periphery to be cut out in a partially arcuate shape.

[0043] On the other hand, the downstream-side internal flow passage L2 opens to the bottom surface of the downstream-side annular groove M2, as shown in Figures 3 and 5 to 7. More specifically, the opening L21 of the downstream-side internal flow passage L2 is formed to be the same as or smaller than the radial groove width of the downstream-side annular groove M2. In other words, the opening L21 of the downstream-side internal flow passage L2 is formed between the outer side surface and the inner side surface of the downstream-side annular groove M2.

[0044] The opening L11 of the upstream internal flow path L1, which is connected to the upstream annular groove M1, and the opening L21 of the downstream internal flow path L2, which is connected to the downstream annular groove M2, as shown in Figures 4 and 7, are formed so as to be offset from each other in the circumferential direction when viewed from above.

[0045] A plurality of upstream internal flow passages L1 communicate with the upstream annular groove M1. In this embodiment, one upstream internal flow passage L1 communicates with the upstream annular groove M1 through a virtual annular groove in the upstream annular groove M1. This upstream annular groove M1 has a recessed shape, and its bottom surface is formed at a position different from the opening L11 portion shown in FIG. 6 and shallower than the downstream annular groove M2. A plurality of upstream internal flow passages L1 communicating with the upstream annular groove M1 are formed at equal intervals in the circumferential direction in the upstream annular groove M1. Looking at each upstream internal flow passage L1, a circumferential end of the upstream annular groove M1 opens into the inner circumferential surface on the valve seat surface 31s side that forms the upstream internal flow passage L1. Two upstream internal flow passages L1 adjacent to each other in the circumferential direction are connected by a single upstream annular groove M1.

[0046] Furthermore, the downstream annular groove M2 is connected to a plurality of downstream internal flow paths L2. In this embodiment, one downstream internal flow path L2 is connected to a plurality of downstream annular grooves M2. The plurality of downstream internal flow paths L2 connected to the downstream annular groove M2 are formed radially at equal intervals in the circumferential direction of the downstream annular groove M2.

[0047] As shown in Figures 5 and 6, the upstream annular groove M1 and the downstream annular groove M2 are formed from the valve seat surface 31s toward the lower surface 31t, and have different depths. In this embodiment, the downstream annular groove M2 is deeper than the upstream annular groove M1. The upstream annular groove M1, which is a shallow annular groove, is connected to an upstream internal flow path L1 that penetrates from the lower surface 31t on the opposite side from the valve seat surface 31s. The downstream annular groove M2, which is a deep annular groove, is connected to a linear downstream internal flow path L2 that is formed from a side surface other than the valve seat surface 31s and the lower surface 31t (here, the outer peripheral surface 31u).

[0048] In this embodiment, the downstream annular groove M2 and the linear downstream internal flow passage L2 intersect with each other, and the linear downstream internal flow passage L2 is directly connected to the downstream annular groove M2. The downstream internal flow passage L2 is also twisted relative to the upstream internal flow passage L1, and is also twisted relative to the upstream annular groove M1.

[0049] <Simulation results> Next, the maximum flow rate when the fluid control valve is fully open and the amount of seat leakage when the fluid control valve is fully closed are compared between the fluid control valve using the orifice 31 of this embodiment (this embodiment) and the fluid control valve using a conventional orifice (conventional example).

[0050] In the conventional orifice, the upstream internal flow passage opens to the bottom surface of the upstream annular groove, and the downstream internal flow passage opens to the bottom surface of the downstream annular groove. In addition, the configuration of the fluid control valve other than the orifice is common to this embodiment and the conventional example.

[0051] As shown in Fig. 8, the maximum flow rate in the fully open state is higher in this embodiment than in the conventional example. Also, as shown in Fig. 9, when the drive voltage is fully closed from 70% or more of the maximum value (100%) to the maximum value (100%) of the drive voltage, the amount of seat leakage is lower in this embodiment than in the conventional example.

[0052] <Effects of this embodiment> In the fluid control device 100 configured as described above, the upstream internal flow passage L1 opens flush with the valve seat surface 31s, and the opening L11 extends further outward than the upstream annular groove M1 in a plan view. This improves the maximum flow rate while reducing seat leakage. Specifically, in a configuration in which the upstream internal flow passage L1 opens on the bottom surface of the upstream annular groove M1, the size of the opening L11 is limited by the groove width of the upstream annular groove M1. However, in this embodiment, the opening size of the upstream internal flow passage L1 is not limited by the groove width of the upstream annular groove M1. This improves the maximum flow rate. Furthermore, the groove width of the upstream annular groove M1 can be narrowed regardless of the opening size of the upstream internal flow passage L1. This allows the area of ​​the valve seat surface 31s to be increased, thereby reducing seat leakage. Furthermore, increasing the area of ​​the valve seat surface 31s reduces stress generated between the valve seat surface 31s and the seat surface 32s in the fully closed state, thereby reducing damage to the seat surface 32s or the valve seat surface 31s.

[0053] <Other embodiments> For example, the opening L21 of the downstream internal flow path L2 may be configured to extend outward from the downstream annular groove M2 in plan view, similar to the opening L11 of the upstream internal flow path L1 in the above embodiment. In this case, the downstream internal flow path L2 opens on the same plane as the valve seat surface 31s, and the opening L21 extends outward from the downstream annular groove M2 in plan view.

[0054] Furthermore, the openings L11 and L21 of the internal flow paths L1 and L2 may be configured to extend outward from the corresponding annular grooves M1 and M2 in plan view.

[0055] Furthermore, the downstream internal flow path L2 does not have to be formed in a straight line and directly connected to the downstream annular groove M2, and the downstream internal flow path L2 may have a vertical flow path portion that opens to the bottom surface of the downstream annular groove M2, and a horizontal flow path portion that is connected to the vertical flow path portion and opens to the outer peripheral surface of the orifice 31.

[0056] Furthermore, in the above embodiment, one upstream annular groove M1 and two downstream annular grooves M2 are formed on the valve seat surface 31s, but two upstream annular grooves M1 and one downstream annular groove M2 may be formed, or multiple upstream annular grooves M1 and multiple downstream annular grooves M2 may be formed.

[0057] The fluid control valve 3 may be a solenoid valve or a valve using other actuators in addition to a piezoelectric valve.

[0058] The flow rate measuring unit in the above embodiment is of a pressure type, but may be of a thermal type.

[0059] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention. [Explanation of symbols]

[0060] 100 Fluid control device R1...Upstream flow path R2...downstream flow path 3. Fluid Control Valve 31 Orifice 31s...Valve seat surface 31t...bottom surface 31u...outer circumferential surface L1: Upstream internal flow passage L11: Opening of the upstream internal flow passage L2: Downstream internal flow passage L21: Opening of the downstream internal flow passage M1: Upstream annular groove M2...Downstream annular groove 32 Valve body 32s···Seating surface 4. Flow rate measurement section 5 Valve control section

Claims

1. A fluid control valve that controls a fluid from an upstream flow path to flow into a downstream flow path, an orifice having a valve seat surface; a valve body having a seating surface that seats on the valve seat surface, The orifice is an annular groove formed on the valve seat surface; an internal flow path that communicates with the upstream flow path or the downstream flow path and that opens at the annular groove, The internal flow path opens to the same plane as the valve seat surface, and the opening extends outward beyond the annular groove in a plan view.

2. The internal flow path is an upstream internal flow path communicating with the upstream flow path; a downstream internal flow path communicating with the downstream flow path, The annular groove is an upstream annular groove into which the upstream internal flow path opens; a downstream annular groove into which the downstream internal flow path opens, 2. The fluid control valve according to claim 1, wherein the upstream internal flow passage opens to the same plane as the valve seat surface, and the opening extends outward beyond the upstream annular groove in plan view; or the downstream internal flow passage opens to the same plane as the valve seat surface, and the opening extends outward beyond the downstream annular groove in plan view.

3. The fluid control valve according to claim 2 , wherein the upstream annular groove and the downstream annular groove are formed in the valve seat surface in a substantially concentric shape.

4. The fluid control valve according to claim 2 or 3, wherein the upstream annular groove and the downstream annular groove are alternately formed on the valve seat surface.

5. a plurality of the upstream internal flow paths are open to the upstream annular groove, The fluid control valve according to claim 2 , wherein a plurality of the downstream internal flow passages open into the downstream annular groove.

6. The fluid control valve according to claim 5 , wherein the opening of the upstream internal flow path and the opening of the downstream internal flow path are formed to be shifted from each other in the circumferential direction in the plan view.

7. The fluid control valve according to claim 2 , wherein the upstream annular groove and the downstream annular groove have different depths.

8. 8. The fluid control valve according to claim 7, wherein an internal flow passage formed by penetrating from a lower surface opposite to the valve seat surface communicates with a shallower annular groove of the upstream annular groove or the downstream annular groove.

9. 9. The fluid control valve according to claim 7, wherein a linear internal flow path formed from a side surface other than the valve seat surface and a lower surface opposite to the valve seat surface communicates with the deeper annular groove of the upstream annular groove or the downstream annular groove.

10. A fluid control valve according to any one of claims 1 to 9; a flow rate measuring unit for measuring a flow rate of the flow path; a valve control unit that controls the fluid control valve based on a measurement value measured by the flow rate measurement unit.

Images