Flow Control Valve

Abstract

To provide a flow control valve having a small number of components to simply form a fluid passage when forming a plurality of grooves in a valve seat to make a seat distance longer.SOLUTION: The flow control valve includes: a valve seat 27 formed on a valve box 22 where a valve element is seated; an inflow passage 33 opened in a center part of the valve seat 27 for guiding fluid into an opening 36; and an outflow passage 41 having a joint part 28 encircling the valve seat 27. The valve seat 27 is formed with a plurality of inflow grooves 31 and a plurality of outflow grooves 32. The inflow grooves 31 extend from the opening 36 of the inflow passage 33 to the joint part 28 so as to form a first partition wall 44 between the joint part 28 and itself, and are formed side by side at predetermined peripheral spaces around the opening 36. The outflow grooves 32 are formed between the adjacent inflow grooves 31, and extend from the joint part 28 to the opening 36 so as to form a second partition wall 45 between the opening 36 and itself.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a flow control valve used in a mass flow controller. [Background technology]

[0002] Mass flow controllers used in semiconductor manufacturing equipment have become thinner in recent years. Accordingly, it has become essential for the flow control valve, which is a component of the mass flow controller, to be made smaller. When the flow control valve is made smaller, the flow rate of the fluid flowing through the flow control valve also decreases. The flow rate of the fluid flowing through the flow control valve depends on the relationship between the distance between the seating surface of the valve body and the valve seat surface of the valve seat, and the seat distance between the inflow passage from the upstream side and the outflow passage to the downstream side.

[0003] Conventional flow control valves designed to increase the seat distance (to increase the flow area) are described in, for example, Patent Document 1 and Patent Document 2. As shown in FIG. 6, the flow control valve disclosed in Patent Document 1 includes a valve body 4 having a circular recess 3 to which an upstream passage 1 and a downstream passage 2 open, a cylindrical valve seat member 5 housed in the circular recess 3, and a valve element 7 seated on a valve seat 6 of the valve seat member 5.

[0004] The upstream passage 1 opens into the center of the inner bottom surface 3a of the circular recess 3. The downstream passage 2 opens into the peripheral wall 3b of the circular recess 3. As shown in FIG. 7, the valve seat 6 of the valve seat member 5 is formed in a circular shape when viewed from the valve body side, and has a central hole 8 located in the center and first to sixth annular grooves 9 to 14 arranged concentrically around the central hole 8.

[0005] A plurality of first communication holes 15 extending in the axial direction of the valve seat member 5 open into the first annular groove 9 adjacent to the central hole 8 and into the third and fifth annular grooves 11, 13. The first communication holes 15 are connected to a large diameter passage 16 formed inside the valve seat member 5 as shown in FIG. 6. The large diameter passage 16 is connected to the upstream passage 1. Therefore, the fluid in the upstream passage 1 flows into the first, third and fifth annular grooves 9, 11, 13 through the large diameter passage 16 and the first communication holes 15.

[0006] On the other hand, as shown in FIG. 7, a plurality of second communication holes 17 extending in the axial direction of the valve seat member 5 are opened in the second, fourth and sixth annular grooves 10, 12 and 14. As shown in FIG. 6, the central hole 8 and the second communication hole 17 are connected to a third communication hole 18 extending in the radial direction of the valve seat member 5. The third communication hole 18 is opened to the outer peripheral surface 5a of the valve seat member 5. An annular fluid chamber 19 is formed between the outer peripheral surface 5a of the valve seat member 5 and the peripheral wall 3b of the circular recess 3. This annular fluid chamber 19 is connected to the downstream passage 2. Therefore, the fluid in the central hole 8 and the second, fourth and sixth annular grooves 10, 12 and 14 flows through the second communication hole 17, the third communication hole 18 and the fluid chamber 19 to the downstream passage 2.

[0007] In this flow control valve, when the valve body 7 moves away from the valve seat 6, the fluid in the first, third and fifth annular grooves 9, 11, 13 flows into the central hole 8 and the second, fourth and sixth annular grooves 10, 12, 14. Therefore, this flow control valve has a longer seat distance compared to a general valve having only one annular valve seat, making it possible to increase the flow rate. The flow control valve shown in Patent Document 2 has the same configuration as the flow control valve shown in Patent Document 1, that is, it has a configuration in which concentric upstream passages and downstream passages are arranged alternately and multiplely on the valve seat. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 5735331 [Patent Document 2] Patent No. 5606087 Summary of the Invention [Problem to be solved by the invention]

[0009] The flow control valve disclosed in Patent Document 1 has a problem that the number of parts is increased because the valve seat member 5 is required in addition to the valve body 4. In addition, the configuration of the fluid passage connecting the central hole 8 of the valve seat 6 and the first to sixth annular grooves 9 to 14 to the upstream passage 1 and the downstream passage 2 is complicated, and the fluid passage portion cannot be easily formed. There are mainly two reasons why the fluid passage becomes complicated. The first reason is that the first and second communication holes 15, 17 extending in the axial direction of the valve seat member 5 and opening into the first to sixth annular grooves 9 to 14 must be provided for each annular groove. The second reason is that the third communication hole 18 extending in the radial direction of the valve seat member 5 is required to connect the multiple second communication holes 17 to the fluid chamber 19. The flow control valve disclosed in Patent Document 2 also has the same problem as the flow control valve shown in Patent Document 1.

[0010] An object of the present invention is to provide a flow control valve which has a small number of parts and can easily form fluid passages when a plurality of grooves are formed in the valve seat to increase the seat distance. [Means for solving the problem]

[0011] In order to achieve this object, the flow control valve of the present invention comprises a valve seat formed in a valve box and consisting of a flat surface on which a valve body sits, an inlet passage opening in the center of the valve seat and directing a fluid to the opening through the inside of the valve box, and an outlet passage having a junction surrounding the valve seat and allowing the fluid to flow out from the junction, and the valve seat is formed with a plurality of inlet grooves extending from the opening of the inlet passage toward the junction so as to form a partition between the junction and the outlet groove, and arranged at predetermined intervals in the circumferential direction around the opening, and a plurality of outlet grooves formed between adjacent inlet grooves and extending from the junction to the opening so as to form a partition between the opening and the outlet groove.

[0012] In the flow control valve of the present invention, the inflow groove and the outflow groove may be formed in a spiral shape centered on the opening of the inflow passage.

[0013] In the flow control valve of the present invention, the inflow groove and the outflow groove may be formed radially from the opening of the inflow passage as a center. Effect of the Invention

[0014] According to the present invention, it is possible to provide a flow control valve which has a reduced number of parts and enables a fluid passage to be easily formed when a plurality of grooves are formed in the valve seat to increase the seat distance. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view of a main part of a flow control valve according to the present invention. [Diagram 2] FIG. 2 is an enlarged plan view showing a portion of the valve body. [Diagram 3] FIG. 3 is an enlarged perspective cross-sectional view of a portion of the valve body. [Figure 4] FIG. 4 is an enlarged perspective cross-sectional view showing a valve seat portion. [Diagram 5] FIG. 5 is a plan view showing a modified example of the valve seat. [Figure 6] FIG. 6 is a cross-sectional view showing a part of a conventional flow control valve. [Figure 7] FIG. 7 is a plan view of a valve seat of a conventional flow control valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An embodiment of a flow control valve according to the present invention will now be described in detail with reference to Fig. 1 to Fig. 4. The cut position in Fig. 1 is the position indicated by line II in Fig. 2. The flow control valve 21 shown in FIG. 1 includes a valve body 22 located on the lower side in FIG. The valve body 22 is made of a metal material such as stainless steel, and has a circular recess 24 that opens toward the actuator 23 .

[0017] The circular recess 24 has a circular opening and is formed to have a predetermined depth. A cylindrical valve body 25 is housed in the circular recess 24. The valve body 25 is connected to the actuator 23 and driven by the actuator 23 to move in the axial direction (the up and down direction in FIG. 1) within the circular recess 24. A gap is formed between the outer circumferential surface of the valve body 25 and the peripheral wall 24a of the circular recess 24. The opening of the circular recess 24 is sealed by a seal structure (not shown) including the actuator 23.

[0018] As shown in FIG. 2, the bottom 26 of the circular recess 24 is composed of a valve seat 27 located in the center and a confluence portion 28 consisting of an annular recess surrounding the valve seat 27. The valve seat 27 is formed in a circular shape when viewed from the valve body 25 side. A plurality of inflow grooves 31 and a plurality of outflow grooves 32, which will be described later, are recessed in the valve seat 27. The seat surface 27a of the valve seat 27 according to this embodiment, i.e., the portion of the valve seat 27 where the inflow grooves 31 and the outflow grooves 32 are not formed, is formed to be a flat surface. In the fully closed state, the valve body 25 is seated on the valve seat 27 in a state of being in close contact with the entire seat surface 27a.

[0019] An inflow passage 33 opens at the center of the valve seat 27. As shown in FIG. 1, the inflow passage 33 is composed of an inflow hole 34 that opens at one side of the valve box 22 (the left side in FIG. 1) and extends in the valve box 22 in a direction perpendicular to the axial direction of the valve body 25, and an inflow side communication hole 35 that extends in the valve box 22 in the axial direction of the valve body 25 from the inflow hole 34 toward the center of the valve seat 27. The inflow side communication hole 35 opens at the center of the valve seat 27. The inflow hole 34 and the inflow side communication hole 35 can be formed by machining. The fluid passing through this flow control valve 21 first flows into the inflow hole 34. The inflow passage 33 guides the fluid that flows into the inflow hole 34 through the inside of the valve box 22 to an opening 36 located at the center of the valve seat 27.

[0020] An outflow side communication hole 42 which is a part of the outflow passage 41 opens into the junction 28. The outflow passage 41 is composed of an outflow hole 43 which opens into the other side of the valve box 22 (the right side in FIG. 1 ) and extends within the valve box 22 in a direction perpendicular to the axial direction of the valve disc 25, an outflow side communication hole 42 which extends within the valve box 22 in the axial direction of the valve disc 25 from the outflow hole 43 toward the junction 28, and the junction 28 which is connected to the outflow side communication hole 42. The outflow passage 41 allows the fluid to flow out of the junction 28 to the outside of the valve box 22. The outflow side communication hole 42, the outflow hole 43, and the junction 28 which constitute the outflow passage 41 can all be formed by machining.

[0021] As shown in Figures 2 and 3, the multiple inflow grooves 31 formed in the valve seat 27 each extend from the opening 36 of the inflow passage 33 toward the junction 28. In this embodiment, the inflow grooves 31 extend in four directions from the opening 36 of the inflow passage 33. Each inflow groove 31 is formed so that one end located on the central side of the valve seat 27 is connected to the opening 36, and gradually curves in one circumferential direction (counterclockwise in Figure 2) from the opening 36 toward the junction 28. In other words, the multiple inflow grooves 31 are arranged at predetermined intervals in the circumferential direction centered on the opening 36, and are formed in a spiral shape centered on the opening 36. The other end of the inflow groove 31 adjacent to the junction 28 is closed. A first partition wall 44 is formed between this other end and the junction 28.

[0022] Between these inflow grooves 31, that is, between adjacent inflow grooves 31, outflow grooves 32 are formed. Outlet groove 32 is formed so that one end is connected to junction 28 and extends from junction 28 along inlet groove 31 toward opening 36 of inlet passage 33. Therefore, outlet groove 32 is also formed in a spiral shape with opening 36 of inlet passage 33 as its center.

[0023] The other end of the outflow groove 32 adjacent to the opening 36 is closed, and a second partition wall 45 is formed between this other end and the opening 36 . The inlet groove 31 and the outlet groove 32 can be formed by machining the valve body 22. When the inlet groove 31 and the outlet groove 32 are to be formed shallow, these grooves can be formed by, for example, etching.

[0024] In the flow control valve 21 configured in this manner, when the valve element 25 is seated on the valve seat 27, the open portions of the inflow groove 31 and the outflow groove 32 are each blocked by the valve element 25. In this state, the inflow passage 33 connected to the inflow groove 31 and the outflow passage 41 connected to the outflow groove 32 do not communicate with each other, and no fluid passes through the flow control valve 21.

[0025] When the valve disc 25 moves away from the valve seat 27, as shown by the arrows in Fig. 4, the fluid in the inflow groove 31 flows through the gap between the valve disc 25 and the valve seat 27 and overflows into the outflow groove 32. The fluid that has entered the outflow groove 32 flows through the outflow groove 32 and flows out to the junction 28. Then, the fluid that has flowed out of all the outflow grooves 32 joins together in the junction 28 and flows out of the valve box 22 through the outflow side communication hole 42 and the outflow hole 43.

[0026] For this reason, in this flow control valve 21, when guiding fluid to the multiple inflow grooves 31, there is no need to form a passage extending in the axial direction of the valve body 25 for each groove, and this can be done using a single inflow side communicating hole 35. Also, when discharging fluid from the multiple outflow grooves 32, the fluids are joined at a single annular joining portion 28, so there is no need to form a passage extending in the axial direction of the valve body 25 for each groove, and all of the fluid can be discharged through a single outflow side communicating hole 42. Furthermore, since the inflow groove 31 and the outflow groove 32 in this embodiment are formed in the valve box 22, a valve seat member separate from the valve box as described in Patent Document 1 is not required.

[0027] Therefore, according to this embodiment, it is possible to provide a flow control valve that has a small number of parts and allows for a simple formation of fluid passages when a plurality of grooves are formed in the valve seat to increase the seat distance.

[0028] In this embodiment, the inflow groove 31 and the outflow groove 32 are formed in a spiral shape centered on the opening 36 of the inflow passage 33. Therefore, the inflow groove 31 and the outflow groove 32 can be formed in the limited space of the valve seat 27 so that the seat distance is as long as possible.

[0029] (Modifications of inflow and outflow grooves) The inflow groove 31 and the outflow groove 32 can be configured as shown in Fig. 5. In Fig. 5, the same or equivalent members as those described with reference to Figs. 1 to 4 are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate. The inflow groove 31 and the outflow groove 32 shown in FIG. 5 are formed radially from the opening 36 of the inflow passage 33 as the center.

[0030] More specifically, the inflow groove 31 extends linearly from the opening 36 of the inflow passage 33 toward the radial outside of the circular recess 24. The inflow grooves 31 are formed at positions aligned at predetermined intervals around the circumference of the circular recess 24. The outflow groove 32 is formed between two adjacent inflow grooves 31 and extends linearly in the radial direction of the circular recess 24 . Even when the inflow groove 31 and the outflow groove 32 are formed as shown in FIG. 5, a flow control valve can be provided in which the number of parts is reduced and the fluid passages can be easily formed by forming multiple grooves in the valve seat to increase the seat distance. [Explanation of symbols]

[0031] 21...flow control valve, 22...valve body, 24...circular recess, 24a...peripheral wall, 27...valve seat, 28...junction, 31...inflow groove, 32...outflow groove, 33...inflow passage, 36...opening, 41...outflow passage, 44...first partition, 45...second partition.

Claims

1. A valve seat formed on the valve body and having a flat surface on which the valve body is seated; an inlet passage that opens to a center portion of the valve seat and guides a fluid through the valve body to the opening; an outlet passage having a junction portion surrounding the valve seat and through which a fluid flows out from the junction portion; The valve seat has: a plurality of inlet grooves extending from the opening of the inlet passage toward the junction so as to form a partition wall between the junction and the opening, the plurality of inlet grooves being arranged at predetermined intervals in a circumferential direction around the opening; a plurality of outlet grooves are formed between adjacent inlet grooves and extend from the confluence toward the opening so as to form a partition between the opening and the outlet groove.

2. 2. The flow control valve according to claim 1, A flow control valve, wherein the inflow groove and the outflow groove are formed in a spiral shape centered on the opening of the inflow passage.

3. 2. The flow control valve according to claim 1, A flow control valve, wherein the inflow groove and the outflow groove are formed radially from the opening of the inflow passage as a center.

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