Fluid control valve and fluid control device

Abstract

To suppress turbulence in a fluid flow field to reduce an unexpected spike behavior.SOLUTION: A fluid control valve 3 comprises: a valve seat member 4 that has a first internal flow path 411 provided between an upstream side flow path 51(A) and a downstream side flow path 51(B), and connected to the upstream side flow path 51(A), and a second internal flow path 412 connected to the downstream side flow path 51(B); and a diaphragm 721 into which fluid having flowed into the first internal flow path 411 from the upstream side flow path 51(A) flows, and that is arranged so as to form a gap X whose flow direction is different from that of the first internal flow path 411 between itself and the valve seat member 4. The second internal flow path 422 is open to an inside peripheral surface 43 forming the first internal flow path 421. The valve seat member 4 has a chamfered part 46 facing a junction J of the first internal flow path 411 and the gap X.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] As a conventional fluid control valve, as shown in Patent Document 1, there is provided a valve seat member provided between an upstream-side flow path and a downstream-side flow path and having an internal flow path formed therein for communicating these flow paths, and a diaphragm provided apart from the valve seat member. The fluid flowing from the upstream-side flow path into the internal flow path is configured to flow into the gap between the valve seat member and the diaphragm while changing its flow direction.

[0003] In such a configuration, the gap between the valve seat member and the diaphragm varies with the movement of the diaphragm. For example, if the set flow rate is increased, the gap widens, and if the set flow rate is decreased, the gap narrows.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the performance evaluation of a fluid control device including the above-described fluid control valve, the inventor of the present application confirmed that, as shown in FIG. 13, when the set flow rate was changed stepwise, a spike behavior occurred in which the output (measured flow rate) dropped to the negative side at the timing of changing to a certain set flow rate.

[0006] As a result of intensive study on the cause of this spike behavior, it was speculated that when the gap between the valve seat member and the diaphragm reaches a certain width, due to the wall resistance of the internal flow path, a pressure loss caused by the turbulence of the fluid flow field occurs, and this is the cause, and the phenomenon that the flow rate that should increase instantaneously decreases was considered to occur.

[0007] Therefore, the present invention has been made by the inventors of the present application through intensive study on the cause of the spike behavior that has not been focused on so far, and its main problem is to reduce unexpected spike behavior by suppressing the turbulence of the fluid flow field described above.

Means for Solving the Problems

[0008] That is, the fluid control valve according to the present invention is provided between the upstream-side flow path and the downstream-side flow path, and has a valve seat member having a first internal flow path connected to the upstream-side flow path and a second internal flow path connected to the downstream-side flow path, and a diaphragm disposed so as to form a gap in which the fluid flowing into the first internal flow path from the upstream-side flow path flows and whose flow direction is different from that of the first internal flow path, between the diaphragm and the valve seat member. In the fluid control valve configured such that the gap varies with the movement of the diaphragm, the second internal flow path opens to the inner peripheral surface forming the first internal flow path, and the valve seat member is characterized by having a chamfered portion facing the confluence portion of the first internal flow path and the gap.

[0009] With such a configuration, since the second internal flow path opens to the inner peripheral surface forming the first internal flow path, the fluid flowing into the first internal flow path from the upstream-side flow path flows out to the downstream-side flow path through the second internal flow path. As a result, compared with a configuration in which the second internal flow path is not opened to the inner peripheral surface forming the first internal flow path, the flow rate of the fluid flowing into the gap between the valve seat member and the diaphragm can be suppressed. Moreover, since the valve seat member has a chamfered portion facing the confluence portion of the first internal flow path and the gap, the fluid easily flows into the above-described gap. For these reasons, it is possible to reduce the resistance to the fluid flowing into the gap, suppress the disturbance of the fluid flow field, and as a result, reduce the unexpected spike behavior that may occur when the gap is changed step by step. Specific analysis data showing this effect will be described later.

[0010] It is preferable that the second internal flow path is linear. In this case, the fluid flowing from the first internal flow path into the second internal flow path flows smoothly into the downstream flow path, so that the flow rate of the fluid flowing into the gap can be more reliably suppressed. Also, the processing of the second internal flow path is simple.

[0011] In order to ensure the workability of the chamfered portion, it is preferable that at least a part of the chamfered portion is a flat surface facing the confluence point.

[0012] In order to more reliably reduce the spike behavior, it is preferable that the valve seat member further has a third internal flow path with one end opening to the gap and the other end opening to the second internal flow path.

[0013] As a more specific embodiment, it includes a valve body that can be separated from and contacted with the valve seat, and a drive shaft that penetrates the first internal flow path and transmits the displacement of the actuator to the valve body, and the flow direction of the fluid flowing along the drive shaft in the first internal flow path is different from the flow direction of the fluid flowing through the gap.

[0014] It is preferable that the valve seat member has an annular convex portion surrounding the gap, and a notch portion is provided at one or more locations of the annular convex portion. With such a configuration, the fluid flowing into the gap flows out of the gap not only through the second internal flow path but also through the notch portion, so that the disturbance of the fluid flow field can be more reliably suppressed, and unexpected spike behavior can be reduced.

[0015] Moreover, the fluid control valve according to the present invention is provided between an upstream-side flow path and a downstream-side flow path, and includes a valve seat member having a first internal flow path connected to the upstream-side flow path and a second internal flow path connected to the downstream-side flow path, and a diaphragm disposed so as to form a gap between the valve seat member and the first internal flow path into which the fluid flowing from the upstream-side flow path into the first internal flow path flows and whose flow direction is different from that of the first internal flow path. In the fluid control valve, a resistance reducing portion for reducing the resistance to the fluid flowing into the gap is further provided, and the resistance reducing portion is a through-flow path formed by opening the second internal flow path on the inner peripheral surface forming the first internal flow path, or a chamfered portion formed on the valve seat member and facing the confluence portion of the first internal flow path and the gap. In the fluid control valve configured as described above, since the resistance reducing portion for reducing the resistance to the fluid flowing into the gap between the valve seat member and the diaphragm is provided, the fluid can easily flow through this gap, and the turbulence of the fluid flow field can be prevented. Thereby, it is possible to suppress the unexpected spike behavior that may occur when the above-described gap is changed stepwise.

[0016] Furthermore, the fluid control device according to the present invention is characterized by including the above-described fluid control valve. In such a fluid control device, the same operational effects as those of the above-described fluid control valve can be achieved.

Effects of the Invention

[0017] According to the present invention configured as described above, in the fluid control valve configured such that the fluid flows into the gap that varies with the movement of the diaphragm, the turbulence of the fluid flow field can be suppressed, and the unexpected spike behavior can be reduced.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0019] Hereinafter, an embodiment of a fluid control device incorporating a fluid control valve according to the present invention will be described with reference to the drawings.

[0020] As shown in FIG. 1, the fluid control device 100 of the present embodiment is, for example, a mass flow controller used in a semiconductor manufacturing apparatus, and includes a body 5 that forms a flow path 51 through which a fluid such as a gas for a semiconductor process flows, a flow rate detection mechanism 2 that senses the flow rate of the fluid flowing through the flow path 51 of the body 5, a fluid control valve 3 that controls the flow rate of the fluid flowing through the flow path 51, and a control unit C that controls the valve opening degree of the fluid control valve 3 so as to bring the measured flow rate output from the flow rate detection mechanism 2 close to a predetermined set flow rate. Each part will be described in detail below.

[0021] The body 5 is in a block shape through which the above-described flow path 51 passes. An external inflow pipe (not shown) is connected to the upstream end of the flow path 51, and an external outflow pipe (not shown) is connected to the downstream end.

[0022] As the flow rate detection mechanism 2, various types such as thermal, differential pressure, Coriolis, and ultrasonic can be considered. Here, a so-called thermal flow rate detection mechanism is adopted. This thermal flow rate detection mechanism 2 includes a thin pipe 21 connected in parallel with the flow path 51 so that a predetermined proportion of the fluid flowing through the flow path 51 is guided, a heater 24 provided in the thin pipe 21, and a pair of temperature sensors 22 and 23 provided before and after the heater 24. When fluid flows through the thin pipe 21, a temperature difference corresponding to the mass flow rate occurs between the two temperature sensors 22 and 23, and the flow rate is configured to be measured based on this temperature difference.

[0023] In this embodiment, while providing a long housing 25 that houses the thin pipe 21, the heater 24, the temperature sensors 22 and 23, and the surrounding electric circuit, a pair of branch flow paths 2a and 2b are branched from the flow path 51 of the body 5, and the housing 25 is attached to the body 5 so that the inlet of the thin pipe 21 is connected to the upstream branch flow path 2a and the outlet of the thin pipe 21 is connected to the downstream branch flow path 2b. Note that the flow rate sensor is not limited to this method.

[0024] The fluid control valve 3 is of a normally closed type provided on the flow path 51, and includes a valve seat member 4 and a valve body 6 housed in the body 5, and an actuator 7 which is a drive mechanism for driving the valve body 6 to set the valve opening degree, that is, the separation distance between the valve seat member 4 and the valve body 6.

[0025] The valve seat member 4 serves as a valve seat. As shown in FIG. 2, it has a valve seat surface 4a protruding toward the valve body 6 on its lower surface and is made of metal (here, stainless steel is used as the material, but other high heat-resistant and corrosion-resistant alloys such as Hastelloy may also be used). An internal flow path 41 is formed inside it. Note that a high heat-resistant and corrosion-resistant alloy such as Hastelloy may also be used as the material of this valve seat member 4.

[0026] This valve seat member 4 is housed in a cylindrical housing recess 52 provided in the body 5. This housing recess 52 is arranged so as to divide the flow path 51 of the body 5. Among the flow paths 51 divided by this housing recess 52, the upstream flow path (hereinafter also referred to as the upstream-side flow path) 51(A) opens, for example, at the center of the bottom surface of the housing recess 52, and the flow path downstream of this housing recess 52 (hereinafter also referred to as the downstream-side flow path) 51(B) opens, for example, on the side surface or the bottom surface of this housing recess 52.

[0027] And in a state where the valve seat member 4 is housed in the housing recess 52, a gap is formed between the outer peripheral surface of the valve seat member 4 and the inner peripheral surface of the housing recess 52, and the downstream-side flow path 51(B) of the body 5 communicates with the internal flow path 41 through this gap.

[0028] Since the fluid control valve 3 of the present embodiment is characterized by the internal flow path 41 of this valve seat member 4 and its peripheral structure, a more detailed configuration will be described later.

[0029] As shown in FIG. 2, the valve body 6 is disposed opposite to the valve seat member 4 in the housing recess 52 of the body 5, and has a seating surface 6a on its surface (upper surface) that seats on the valve seat surface 4a of the valve seat member 4.

[0030] This valve body 6 is driven by an actuator 7 and moves from a closed state where it contacts the valve seat member 4 to block the upstream-side flow path 51(A) and the downstream-side flow path 51(B) to an open state where it separates from the valve seat member 4 to communicate the upstream-side flow path 51(A) and the downstream-side flow path 51(B). Thus, the direction from the closed state to the open state, that is, the direction in which the driving force of the actuator 7 acts on the valve body 6 is the valve-opening direction. On the other hand, the direction from the open state to the closed state, that is, the direction opposite to the direction in which the driving force of the actuator 7 acts on the valve body 6 is the valve-closing direction.

[0031] As shown in FIG. 1, for example, the actuator 7 includes a piezo stack 71 formed by laminating a plurality of piezo elements, and an actuator body 72 that is displaced by the extension of the piezo stack 71.

[0032] This piezo stack 71 is housed within a casing member 74, and its tip is connected to a protrusion 73 provided, for example, separately or integrally, at the base end of the actuator body 72.

[0033] The actuator body 72 of the present embodiment has a diaphragm 721 and a drive shaft 722 provided at the center of the diaphragm 721, passing through the center of the valve seat member 4 and abutting against the upper surface of the valve body 6. When a predetermined fully open voltage is applied, the piezo stack 71 extends, the actuator body 72 biases the valve body 6 in the valve opening direction, and the valve seat surface 4a separates from the seating surface 6a to be in an open state. Also, if the voltage is below the fully open voltage, the valve seat surface 4a and the seating surface 6a separate by a distance corresponding to the voltage value. Then, the upstream flow path 51(A) and the downstream flow path 51(B) communicate with each other through this gap.

[0034] Also, as shown in FIG. 2, a valve body return spring 8 that biases the valve body 6 in the valve closing direction is provided in contact with the valve body 6. Due to this valve body return spring 8, in the normal state where no voltage is applied to the actuator 7, the valve body 6 is in a closed state. The valve body return spring 8 has an annular shape and is an elastic body such as a leaf spring. Here, the valve body return spring 8 is supported by a spring guide member 10 housed within the housing recess 52 of the body 5, but this spring guide member 10 does not necessarily have to be provided.

[0035] Subsequently, the detailed configuration of the above-described valve seat member 4 will be described.

[0036] As shown in FIG. 2, the valve seat member 4 is interposed between the upstream flow path 51(A) and the downstream flow path 51(B), and has at least a part of the internal flow path 41 including a first internal flow path 411 connected to the upstream flow path 51(A) and a second internal flow path 412 connected to the downstream flow path 51(B).

[0037] The first internal flow path 411 has one end opening to the valve seat surface 4a and the other end opening to the upper surface 42 of the valve seat member 4. A drive shaft 722 for transmitting the displacement of the actuator 7 to the valve body 6 is inserted into the first internal flow path 411. That is, the first internal flow path 411 forms a fluid flow along the drive shaft 722 (along the valve closing direction of the valve body 6).

[0038] One end of the second internal flow path 412 opens to the inner circumferential surface 43 forming the first internal flow path 411, and the other end opens to the outer circumferential surface 44 of the valve seat member 4. That is, the second internal flow path 412 is a through-flow path L that penetrates the valve seat member 4 from the outer circumferential surface 44 of the valve seat member 4 to the first internal flow path 411 and is linear. The second internal flow path 412 here is orthogonal to the first internal flow path 411. In other words, the second internal flow path 412 forms a fluid flow orthogonal to the first internal flow path 411. Note that the second internal flow path 412 may be formed to be inclined with respect to the direction orthogonal to the first internal flow path 411.

[0039] As shown in FIG. 3, the valve seat member 4 of the present embodiment further has a third internal flow path 413 as the internal flow path 41, one end of which opens to the upper surface 42 of the valve seat member 4 and the other end of which opens to the inner circumferential surface 45 forming the second internal flow path 412.

[0040] More specifically, a recess is formed in the upper surface 42 of the valve seat member 4, and this recess is closed by the above-described diaphragm 721. As a result, a gap X is generated between the valve seat member 4 and the diaphragm 721, and the third internal flow path 413 opens to this gap X. That is, the first internal flow path 411 and the third internal flow path 413 communicate with each other through the gap X.

[0041] This gap X is a space that varies with the movement of the diaphragm 721. Specifically, as the diaphragm 721 moves, the separation distance between the valve seat member 4 and the diaphragm 721 varies, and accordingly, the narrowness (width) of the gap X varies. This gap X is formed along the diaphragm 721 and is a space that extends radially outward from the drive shaft 722 described above.

[0042] And the first internal flow path merges into this gap X. More specifically, as described above, since the first internal flow path 411 opens to the upper surface 42 of the valve seat member 4, the merging point J between the first internal flow path 411 and the gap X is the opening formed in this upper surface 42 (see FIG. 3).

[0043] With such a configuration, the fluid that has flowed into the first internal flow path 411 from the upstream flow path 51(A) described above will flow into this gap X while changing the flow direction. That is, the flow direction of the fluid flowing along the drive shaft 722 in the first internal flow path 411 and the flow direction of the fluid flowing in the gap X are different from each other, and specifically, these flow directions are substantially orthogonal to each other.

[0044] In this way, a bent portion Z where the flow direction of the fluid changes is interposed between the first internal flow path 411 and the gap X. Of course, the boundary between the bent portion Z and the first internal flow path 411 and the boundary between the bent portion Z and the gap X cannot be clearly expressed, but at least the region facing the joint portion Y between the diaphragm 721 and the drive shaft 722 (the region shaded in FIG. 3) becomes the bent portion Z.

[0045] Here, as shown in FIG. 3, the valve seat member 4 of the present embodiment has a chamfered portion 46 facing the above-described merging point J.

[0046] This chamfered portion 46 is formed by chamfering the corner formed by the upper surface 42 and the inner circumferential surface 43 of the valve seat member 4, whereby the upper surface 42 and the inner circumferential surface 43 are continuously formed via the chamfered portion 46. That is, the chamfered portion 46 is a surface formed between the inner edge 421 of the upper surface 42 and the upper end 431 of the inner circumferential surface 43, and is formed so as to face the bent portion Z described above.

[0047] At least a part of the chamfered portion 46 is a flat surface formed at a position facing the confluence point J, and is a surface having a truncated conical shape facing the joint portion Y between the diaphragm 721 and the drive shaft 722.

[0048] In the valve seat member 4 configured as described above, since the above-described second internal flow path 412 is formed as a through flow path L that penetrates from the downstream flow path 51(B) to the first internal flow path 411, a part of the fluid flowing through the first internal flow path 411 flows into the second internal flow path 412.

[0049] Thereby, compared with a configuration in which the second internal flow path 412 does not penetrate to the first internal flow path 411, the flow rate of the fluid flowing into the gap X between the valve seat member 4 and the diaphragm 721 can be suppressed.

[0050] That is, the second internal flow path 412 functions as a resistance reducing portion P that reduces the resistance to the fluid flowing into the gap X.

[0051] Furthermore, since the valve seat member 4 of the present embodiment has a chamfered portion 46 facing the bent portion Z where the flow direction of the fluid changes, the fluid easily flows into the gap X. That is, also with respect to this chamfered portion 46, it functions as a resistance reducing portion P that reduces the resistance to the fluid flowing into the gap X.

[0052] Here, in order to evaluate the performance of the fluid control device 100, the results of confirming the behavior of the output (measured flow rate) when the set flow rate is changed stepwise will be described.

[0053] First, before explaining the evaluation results of the fluid control device 100 of the present embodiment, as a comparison target, the results in the case of using the configuration shown in FIG. 4 will be described. Note that the configuration shown in FIG. 4 is different from the fluid control device 100 of the present embodiment in that the second internal flow path 412 does not penetrate to the first internal flow path 411 and the chamfered portion 46 is not formed.

[0054] When the valve voltage (set flow rate) is changed stepwise in this configuration to be compared, as shown in FIG. 5, it can be seen that a spike behavior appears in which the output (measured flow rate) drops to the negative side at the timing of changing to a certain set flow rate.

[0055] And at the timing when this spike behavior occurs (the timing of b in FIG. 5), as can be seen from the simulation results shown in FIG. 5, turbulence occurs in the fluid flow field, and it is presumed that the spike behavior is caused by the pressure loss due to this turbulence.

[0056] On the other hand, FIG. 6 shows the behavior of the output (measured flow rate) when the valve voltage (set flow rate) is changed stepwise in the fluid control device 100 of the present embodiment. As can be seen from FIG. 6, it can be seen that the unexpected spike behavior described above does not occur in the fluid control device 100 of the present embodiment. One of the factors is presumed to be that, as can be seen from the simulation results in FIG. 6, the turbulence in the fluid flow field is suppressed. Note that in this simulation result, it is shown that the fluid indicated by the white line has a lower pressure than the fluid indicated by the black line.

[0057] As described above, according to the fluid control device 100 of the present embodiment, the second internal flow path 412 and the chamfered portion 46 function as a resistance reduction portion P that reduces the resistance to the fluid flowing into the gap X between the valve seat member 4 and the diaphragm 721. Therefore, the fluid can easily flow into the gap X, and the turbulence in the fluid flow field can be suppressed. As a result, it is possible to reduce unexpected spike behavior that may occur when the gap X is changed step by step.

[0058] Note that the present invention is not limited to the above-described embodiment.

[0059] For example, although the valve seat member 4 of the above-described embodiment has the third internal flow path 413 that communicates the second internal flow path 412 and the gap X, as shown in FIG. 7, the valve seat member 4 may not have the third internal flow path 413 formed therein. In such a configuration, the tip portion on the side opposite to the confluence portion J in the gap X will be closed. However, separately from the third internal flow path 413 of the above-described embodiment, a flow path connecting the gap X and the downstream flow path 51(B) may be formed in the valve seat member 4 or the like.

[0060] Even with such a configuration, if the chamfered portion 46 is not formed, unexpected spike behavior appears when the set flow rate is changed step by step. In the configuration shown in FIG. 7, the chamfered portion 46 functions as a resistance reducing portion P that reduces the resistance to the fluid flowing into the gap X. Therefore, similar to the above-described embodiment, it is possible to suppress the disturbance of the fluid flow field and reduce unexpected spike behavior.

[0061] Further, the chamfered portion 46 was a flat surface in the above-described embodiment, but may be a curved surface that curves, for example, toward the bent portion Z or away from the bent portion Z.

[0062] Furthermore, although the second internal flow path 412 was linear in the above-described embodiment, as long as it connects the downstream flow path 51(B) and the first internal flow path 411, for example, it may have a bent shape such that the flow path direction changes one or more times.

[0063] In addition, in the above-described embodiment, the aspect in which both the through-flow path L formed by penetrating the second internal flow path 412 through the first internal flow path 411 and the chamfered portion 46 are formed as the resistance reduction portion P has been described. However, when either the through-flow path L or the chamfered portion 46 sufficiently exhibits the function as the resistance reduction portion P, the other does not necessarily have to be formed. That is, as the valve seat member 4, at least one of the through-flow path L formed by opening the second internal flow path 412 in the inner peripheral surface 43 forming the first internal flow path 411 or the chamfered portion 46 facing the bent portion Z where the fluid flow direction changes may be formed as the resistance reduction portion P.

[0064] Further, as the valve seat member 4, as shown in FIGS. 8 and 9, a notch portion 48 obtained by notching an annular convex portion 47 surrounding the gap X may be provided. This notch portion 48 constitutes a part of the gap X, and specifically, it may be provided, for example, at equal intervals at one or a plurality of locations of the annular convex portion 47. With this configuration, a part of the gap X has its tip end extending to the outer peripheral surface of the valve seat member 4.

[0065] Also, in the configuration in which the notch portion 48 is provided in the valve seat member 4 in this way, as shown in FIG. 10, the third internal flow path 413 does not necessarily have to be formed. According to this configuration, as shown in the upper part of FIG. 11, unexpected spike behavior can be reduced. And, as shown in the simulation result in the lower part of FIG. 11, the fluid flowing into the gap X flows out from the gap X not only through the second internal flow path 412 but also through the notch portion 48, so it can be seen that the disturbance of the fluid flow field is suppressed. Note that in this simulation result, it is shown that the fluid indicated by the white line has a lower pressure than the fluid indicated by the black line.

[0066] In addition, the fluid control device 100 of the above-described embodiment uses a thermal type as the flow rate detection mechanism 2. However, as described in the above-described embodiment, a differential pressure type flow rate detection mechanism 2 may be used.

[0067] That is, as shown in FIG. 12, the fluid control device 100 may be a mass flow controller including a flow rate detection mechanism 2 provided in a flow path 51 through which fluid flows, a fluid control valve 3 provided upstream of the flow rate detection mechanism 2, and a control unit C that controls the fluid control valve 3 so that the measured flow rate by the flow rate detection mechanism 2 becomes a predetermined target flow rate. And this flow rate detection mechanism 2 is composed of a resistance flow path R provided on the flow path 51 and a pair of pressure sensors P1 and P2 that measure the fluid pressures in the flow path 51 on the upstream side and the downstream side of the resistance flow path R. And it is configured to be able to measure the flow rate of the fluid flowing through the flow path 51 based on the pressure measurement values by the pressure sensors P1 and P2 and the resistance value of the resistance flow path R.

[0068] In addition, some or all of the above-described embodiments and modified embodiments may be appropriately combined. Needless to say, the present invention is not limited to the above embodiments, and various modifications and combinations of embodiments are possible without departing from the spirit of the invention.

Explanation of Reference Numerals

[0069] 100 ··· Fluid control device 2 ··· Flow rate detection mechanism 3 ··· Fluid control valve 4 ··· Valve seat member 5 ··· Body 6 ··· Valve body 7 ··· Actuator 721 ··· Diaphragm 4a ··· Valve seat surface 41 ··· Internal flow path 411 ··· First internal flow path 412 ··· Second internal flow path 413 ··· Third internal flow path 46 ··· Chamfered portion P ··· Resistance reduction portion X ··· Gap Z ··· Bent portion L ··· Through-flow path

Claims

1. A valve seat member provided between an upstream-side flow path and a downstream-side flow path, having a first internal flow path connected to the upstream-side flow path and a second internal flow path connected to the downstream-side flow path, In a fluid control valve comprising a diaphragm arranged so as to form, between the diaphragm and the valve seat member, a gap through which fluid flowing into the first internal flow path from the upstream-side flow path flows and whose flow direction is different from that of the first internal flow path, The second internal flow path opens to the inner peripheral surface forming the first internal flow path, The fluid control valve, wherein the valve seat member has a chamfered portion facing the confluence point of the first internal flow path and the gap.

2. The fluid control valve according to claim 1, wherein the second internal flow path is linear.

3. The fluid control valve according to claim 1 or 2, wherein at least a part of the chamfered portion is a flat surface facing the confluence point.

4. The fluid control valve according to any one of claims 1 to 3, wherein the valve seat member further has a third internal flow path with one end opening to the gap and the other end opening to the second internal flow path.

5. A valve body that can be separated from and contacted with the valve seat, A drive shaft that penetrates the first internal flow path and transmits the displacement of the actuator to the valve body, The fluid control valve according to any one of claims 1 to 4, wherein the flow direction of the fluid flowing along the drive shaft in the first internal flow path is different from the flow direction of the fluid flowing through the gap.

6. The fluid control valve according to any one of claims 1 to 5, wherein the valve seat member has an annular convex portion surrounding the gap, and one or more notches are provided at one or more locations of the annular convex portion.

7. A valve seat member provided between an upstream-side flow path and a downstream-side flow path, having a first internal flow path connected to the upstream-side flow path and a second internal flow path connected to the downstream-side flow path, In a fluid control valve comprising a diaphragm arranged so as to form, between the diaphragm and the valve seat member, a gap through which fluid flowing into the first internal flow path from the upstream-side flow path flows and whose flow direction is different from that of the first internal flow path, Further comprising a resistance reduction portion for reducing the resistance to the fluid flowing into the gap, The fluid control valve, wherein the resistance reduction portion is a chamfered portion formed on the valve seat member and facing the confluence point of the first internal flow path and the gap.

8. A fluid control device comprising the fluid control valve according to any one of claims 1 to 7.

Images