Diaphragm valves and flow control devices

Abstract

Provided is a diaphragm valve which is miniaturized while ensuring a necessary flowrate and which has improved assemblability and maintainability.　This diaphragm valve comprises: a body (10) that defines a flow channel; a diaphragm (40) provided in the bottom surface (15c) of a storage recess (15); a fixing ring (42) screwed with a thread portion (15a) formed in the inner circumferential surface of the storage recess (15) to fix the diaphragm (40) to the body (10); a laminated piezoelectric actuator (22); a support plate (24) that supports the laminated piezoelectric actuator (22); a cylindrical actuator cover (26) which holds a diaphragm presser (27) and which stores thereinside the laminated piezoelectric actuator (22) and has transmitted thereto displacement caused by a piezoelectric effect of the laminated piezoelectric actuator (22); and a fixing member (28) that is screwed with a thread portion (15a) shared with the thread portion (15a) and fixes the position of the support plate (24) in the storage recess (15) cooperatively with the fixing ring (42).

Description

[Technical field]

[0001] The present invention relates to a diaphragm valve and a flow control device using the diaphragm valve as a flow control valve. [Background technology]

[0002] In semiconductor manufacturing processes, particularly in fine processes such as atomic layer deposition, pressure-based flow rate control devices such as those disclosed in Patent Document 1 are used to supply accurately metered amounts of process gas to a processing chamber. The flow rate control device disclosed in Patent Document 1 controls the flow rate of a fluid by adjusting the opening degree of a flow path by operating a diaphragm with a laminated piezoelectric actuator, in which laminated piezoelectric elements are built into a case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6799859 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned flow control device, there is a demand for a smaller and thinner device, while there is also a demand for a certain flow rate of the fluid. There is also a demand for improved ease of assembly and maintenance of the flow control device.

[0005] An object of the present invention is to provide a diaphragm valve which is compact while ensuring a necessary flow rate and has improved ease of assembly and maintenance, and a flow rate control device using this diaphragm valve. [Means for solving the problem]

[0006] The diaphragm valve of the present invention comprises: a block-shaped body defining a flow path; a diaphragm provided on a bottom surface of an accommodating recess formed in the body, the diaphragm defining a part of the flow passage and changing an opening degree of the flow passage; a fixing ring that is screwed into a threaded portion formed on an inner circumferential surface of the accommodating recess to fix the diaphragm to the body; A laminated piezoelectric actuator having piezoelectric elements laminated in a cylindrical casing; a support plate for supporting the laminated piezoelectric actuator; a cylindrical actuator cover that holds a diaphragm presser and accommodates the laminated piezoelectric actuator therein while transmitting displacement caused by a piezoelectric effect of the laminated piezoelectric actuator; A fixing member is provided which is screwed into a threaded portion common to the threaded portion and cooperates with the fixing ring to fix the position of the support plate within the receiving recess.

[0007] Preferably, the fixing member is formed in a cylindrical shape and also serves as a guide member that movably guides the actuator cover in a direction approaching and moving away from the diaphragm.

[0008] More preferably, the support plate is disposed so as to cross the actuator cover through a cutout portion formed opposite the actuator cover, and both ends of the support plate protrude from an outer circumferential surface of the actuator cover, Both ends of the support plate are clamped between the fixing ring and the fixing member.

[0009] The diaphragm valve of the present invention can adopt a configuration further having an elastic member that is provided inside the actuator cover and interposed between the support plate and a receiving portion formed on the actuator cover, and that urges the actuator cover toward the diaphragm.

[0010] Preferably, the inner peripheral surface of the fixing ring has a double hex structure, The actuator cover may be configured to pass through the fixing ring.

[0011] More preferably, the actuator cover may have a constant outer diameter from one end to the other end in the longitudinal direction.

[0012] A configuration can be adopted in which the laminated piezoelectric actuator, the support plate, the actuator cover, the fixing member and the elastic member form an actuator assembly that is detachable from the accommodating recess independent of the diaphragm.

[0013] The flow rate control device of the present invention uses the above-mentioned diaphragm valve as a flow rate control valve for controlling the flow rate. Effect of the Invention

[0014] According to the present invention, there is provided a diaphragm valve which is miniaturized while ensuring a required flow rate and has improved ease of assembly and maintenance, and a flow control device which uses this diaphragm valve as a flow control valve. [Brief description of the drawings]

[0015] [Figure 1A] 1 is an external perspective view of a flow rate control device according to an embodiment of the present invention; [Figure 1B] FIG. 1B is a cross-sectional view of a main portion of FIG. 1A. [Figure 1C] FIG. 2 is a cross-sectional view of a main portion of the flow control device shown in FIG. 1B with an actuator assembly removed from the body. [Diagram 2] FIG. [Figure 3A] FIG. [Figure 3B] FIG. 3B is a plan view of the retaining ring of FIG. 3A. [Figure 4] FIG. [Figure 5A] FIG. [Figure 5B] FIG. 5B is a cross-sectional view of the support plate of FIG. 5A. [Figure 6A] FIG. [Figure 6B] FIG. 6B is a longitudinal cross-sectional view of the actuator cover of FIG. 6A. [Figure 6C] 6B is an external perspective view showing a state in which a support plate is inserted into a cutout portion of the actuator cover shown in FIG. 6A. [Figure 7A] FIG. [Figure 7B] FIG. 7B is a longitudinal cross-sectional view of the guide member of FIG. 7A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description, like elements are given the same reference numerals and duplicated description will be omitted as appropriate. 1A to 1C show a flow rate control device 1 according to this embodiment. 1A to 1C, 101 is an inlet block, 102 is an outlet block, 10 is a body, 20 is an actuator assembly, 110 is an opening / closing valve, and 120 and 130 are pressure detectors.

[0017] The body 10 is formed in a block shape from a metal material such as stainless steel, defines the flow passages 11 and 12, and is disposed on an inlet block 101 and fixed thereto by bolts (not shown). The inlet block 101 is made of a metal material such as stainless steel, and is formed with a flow path 101a connected to the flow path 11, and an opening of the flow path 101a is formed on the lower surface. The outlet side block 102 is formed of a metal material such as stainless steel and is fixed to the side of the body 10 with bolts not shown. A flow path not shown is formed inside the outlet side block 102 which is connected to the flow path 12, and an opening of the flow path is formed on the underside.

[0018] FIG. 1C shows the actuator assembly 20 removed from the body 10. As shown in FIG. 1C, the body 10 is formed with an accommodating recess 15, which is a hole with a circular cross section that opens on the upper surface of the body 10. The accommodating recess 15 is a circular hole with a constant inner diameter from the opening to the bottom surface 15c. The flow paths 11 and 12 open at the bottom surface 15c of the accommodating recess 15. The accommodating recess 15 has a constant inner diameter from the opening on the upper surface of the body 10 to the bottom surface 15c, and a threaded portion 15a is formed on the inner peripheral surface from the upper surface to the middle in the depth direction. In addition, a valve seat 15b consisting of an annular protrusion is formed around the opening of the flow path 11 on the bottom surface 15c of the accommodating recess 15.

[0019] The diaphragm 40 is provided on the bottom surface 15c of the accommodation recess 15. An annular pressing adapter 41 made of a metal material such as stainless steel as shown in FIG. 2 is provided on the outer periphery of the diaphragm 40, and the fixing ring 42 presses the pressing adapter 41 toward the bottom surface 15c of the accommodation recess 15, thereby fixing the diaphragm 40 to the bottom surface 15c of the accommodation recess 15. Although the pressing adapter 41 is used in this embodiment, it is also possible to fix the diaphragm 40 directly with the fixing ring 42 without using the pressing adapter 41. In this case, it is preferable that the shape of the part of the fixing ring 42 that comes into contact with the diaphragm 40 is the same as that of the pressing adapter 41. In this embodiment, the diaphragm 40 is made of a laminate of thin metal plates such as special stainless steel and thin nickel-cobalt alloy plates, with the center bulging upward to form a spherical shell shape with an upwardly convex circular arc shape in its natural state. The diaphragm 40 defines the flow passage connecting the flow passages 11 and 12 in cooperation with the bottom surface of the body 10, and changes the cross-sectional area of ​​the flow passage by elastically deforming to approach and move away from the valve seat 15b. When the diaphragm 40 abuts against the valve seat 15b, the flow passage is closed, and as the diaphragm 40 moves away from the valve seat 15b, the cross-sectional area of ​​the flow passage expands, and the flow rate of the fluid flowing through the flow passage increases.

[0020] The fixing ring 42 is made of a metal material such as stainless steel, and as shown in Figures 3A and 3B, a threaded portion 42a is formed on the outer peripheral surface, and an inner peripheral surface 42b has a double hex structure for engaging a rotary tool. By screwing the threaded portion 42a of the fixing ring 42 into the threaded portion 15a of the accommodating recess 15, the fixing ring 42 presses the presser adapter 41 toward the diaphragm 40, and the diaphragm 40 is fixed to the bottom surface 15c of the accommodating recess 15. By fixing the diaphragm 40 to the body 10 using this fixing ring 42, the actuator assembly 20 can be attached to and detached from the accommodating recess 15 independently of the diaphragm 40. As will be described later, the actuator assembly 20 is mounted in the receiving recess 15 and opens and closes the diaphragm valve.

[0021] The diaphragm valve of the present invention is composed of a body 10, a diaphragm 40, a presser adapter 41, a fixing ring 42 and an actuator assembly 20, and this diaphragm valve is used as a flow control valve for a flow control device 1.

[0022] The pressure detector 120 detects the pressure upstream of an orifice (not shown) provided in the flow passage 12 inside the body 10 . The pressure detector 130 detects the pressure downstream of the orifice (not shown). The flow control device 1 is a so-called pressure-type flow control device, and is equipped with a control circuit (not shown) consisting of hardware such as a processor and a memory, and the necessary software. Based on the pressure P1 detected by the pressure detector 120 and the pressure P2 detected by the pressure detector 130, the flow rate of the fluid flowing through the flow path 12 is measured, and the above-mentioned diaphragm valve is driven and controlled so that the measured flow rate becomes the target flow rate.

[0023] The actuator assembly 20 is for manipulating and actuating the diaphragm 40, and includes a laminated piezoelectric actuator 22, a support plate 24, an actuator cover 26, a diaphragm retainer 27, a guide member 28, a disc spring 30, a support pin 31, a spacer 32, an adjustment cap nut 33, an actuator support 34 and a lock nut 35.

[0024] As shown in FIG. 4, the laminated piezoelectric actuator 22 incorporates laminated piezoelectric elements (not shown) in a cylindrical casing 22a. The casing 22a is made of a metal such as a stainless alloy, and the end face on the hemispherical tip end 22b side and the end face on the base end 22c side are closed. When a voltage is applied to the laminated piezoelectric elements to elongate them, the end face on the tip end 22b side of the casing 22a elastically deforms due to the piezoelectric effect, and the hemispherical tip end 22b is displaced in the longitudinal direction. For example, if the maximum stroke of the laminated piezoelectric elements is 2d, the total length of the laminated piezoelectric actuator 22 is L0 by applying a predetermined voltage V0 that makes the elongation of the laminated piezoelectric actuator 22 d. When a voltage higher than the predetermined voltage V0 is applied, the total length of the laminated piezoelectric actuator 22 is L0+d at maximum, and when a voltage lower than the predetermined voltage V0 (including no voltage) is applied, the total length of the laminated piezoelectric actuator 22 is L0-d at minimum. Therefore, the entire length from the tip end 22b to the base end 22c can be expanded or contracted in the longitudinal direction. In this embodiment, the tip end 22b of the multilayer piezoelectric actuator 22 is semispherical, but this is not limited thereto, and the tip end 22b may be a flat surface. In addition, the method of applying a voltage to the multilayer piezoelectric actuator 22 is not limited to the above-mentioned application method, and other methods can be used. Moreover, power is supplied to the piezoelectric element of the laminated piezoelectric actuator 22 through a power supply line (not shown) led out from the base end portion 22c side of the casing 22a.

[0025] The support plate 24 is a plate material having a substantially rectangular outer shape made of a metal material such as stainless steel. As shown in FIGS. 5A and 5B, a semi-spherical recess 24a is formed in the center of the front surface side into which the tip 22b of the laminated piezoelectric actuator 22 fits. The support plate 24 has a circular recess 24d formed in the center of the rear surface thereof, into which the tip of the support pin 31 fits.

[0026] The actuator cover 26 is made of a metal material such as stainless steel, and is a cylindrical member with a bottom that has a constant outer diameter from the upper end to the lower end as shown in Figures 6A and 6B. Two notches 26a, 26a are formed at the lower end side of the actuator cover 26 at symmetrical positions with respect to the central axis, and an adjustment cap nut 33 and a lock are provided on the outer periphery of the upper end side. A threaded portion 26c into which the nut 35 is screwed is formed. The actuator cover 26 also has a receiving portion 26d at its lower end for receiving the disc spring 30, and a screw hole 26e in the center of the receiving portion into which the support pin 31 is screwed is formed. Furthermore, a mounting recess 26f into which the diaphragm holder 27 is attached is formed on the lower end surface side of the receiving portion 26d.

[0027] As can be seen from Fig. 1B and Fig. 1C, the actuator cover 26 accommodates the laminated piezoelectric actuator 22 therein. The laminated piezoelectric actuator 22 accommodated in the actuator cover 26 needs to be supported by the support plate 24. For this reason, as shown in Fig. 1B, Fig. 1C and Fig. 6C, the support plate 24 is disposed so as to cross the actuator cover 26 through two cutout portions 26a formed opposite to each other, and so that both ends 24b protrude outward from the outer circumferential surface of the actuator cover 26. As will be described later, in a state in which the position of the support plate 24 is fixed in the accommodation recess 15 of the body 10, the actuator cover 26 can move relative to the support plate 24 in the direction of the central axis of the actuator cover 26, but the rotation around the central axis is restricted by the support plate 24 engaging with the cutout portions 26a.

[0028] The diaphragm holder 27 is made of synthetic resin such as polyimide, and has a convexly curved tip that comes into contact with the upper surface of the center of the diaphragm 40 .

[0029] The guide member 28 is made of a metal material such as stainless steel, and is a cylindrical member as shown in Figs. 7A and 7B. A threaded portion 28a is formed on the lower end side of the outer circumferential surface, and a holding groove 28b and a holding groove 28c for holding an O-ring OR are formed at two locations on the inner circumferential surface. The guide member 28 has recesses 28d, into which both ends 24b of the support plate 24 fit, formed at positions symmetrical with respect to the central axis on the inner periphery of the lower end side. As can be seen from Fig. 1B, the guide member 28 functions as a fixing member that holds the support plate 24 in cooperation with the fixing ring 42 by screwing the threaded portion 28a into the threaded portion 15a of the accommodation recess 15, and fixes the position of the support plate 24 in the accommodation recess 15. In addition, the guide member 28 holds two O-rings OR, and the outer circumferential surface of the actuator cover 26 inserted into the guide member 28 slides against the two O-rings OR, so that the actuator cover 26 is guided to be movable in a direction approaching and moving away from the diaphragm 40.

[0030] The support pin 31 is made of a metal material such as stainless steel, and is fixed to the receiving portion 26d of the actuator cover 26 by being screwed into a screw hole 26e of the receiving portion 26d. 1B, a support pin 31 is inserted into the center of the disc spring 30, and an annular spacer 32 is provided on the disc spring 30. When the support plate 24 is fixed to the body 10, the upper end of the disc spring 30 abuts against the support plate 24 via the spacer 32, and the lower end abuts against the receiving portion 26d, and the actuator cover 26 (diaphragm holder 27) is constantly biased toward the diaphragm 40 by its elastic restoring force. The diaphragm 40 is pressed by the diaphragm holder 27 by the elastic restoring force of the disc spring 30, and is pressed against the valve seat (see FIG. 1C), closing the flow path.

[0031] As shown in FIG. 1B, the adjustment cap nut 33 is screwed into the threaded portion 26c of the actuator cover 26, and a metal actuator receiver 34 is disposed between the adjustment cap nut 33 and the actuator cover 26. The actuator receiver 34 is an annular member having a hole for leading out a power supply line for supplying power to the piezoelectric element of the laminated piezoelectric actuator 22, and is disposed at the upper end of the laminated piezoelectric actuator 22 to transmit the driving force of the laminated piezoelectric actuator 22 to the adjustment cap nut 33 and the actuator cover 26. As shown in FIG. 1B, when there is no gap between the adjustment cap nut 33 and the actuator receiver 34, the opening degree of the diaphragm valve is equal to the maximum stroke of the laminated piezoelectric actuator 22, but when there is a space between the adjustment cap nut 33 and the actuator receiver 34, for example, the opening degree of the adjustment cap nut 33 and the diaphragm valve is the maximum stroke minus the length of the space. Based on this principle, the adjustment cap nut 33 adjusts the opening degree of the diaphragm valve. A lock nut 35 is provided to lock the rotational position of the adjustment cap nut 33 .

[0032] Here, the assembly procedure for the actuator assembly 20 will be described. First, the support pin 31 is screwed into the screw hole 26e of the receiving portion 26d of the actuator cover 26 to which the diaphragm holder 27 is attached, and fixed. Next, the disc spring 30 is placed on the outer periphery of the support pin 31 , and the spacer 32 is placed on the disc spring 30 . Next, the support plate 24 is inserted into the cutouts 26a, 26a of the actuator cover 26. At this time, the tip of the support pin 31 fits into the recess 24d on the back side of the actuator cover 26, thereby positioning the actuator cover 26. Next, the guide member 28 with the O-ring OR attached thereto is provided on the outer periphery of the actuator cover 26, and both ends 24b, 24b of the support plate 24 are fitted into the recesses 28d of the guide member 28. Match. Next, the lock nut 35 is screwed onto the threaded portion 26c of the actuator cover 26, the laminated piezoelectric actuator 22 is inserted into the actuator cover 26, and the tip portion 22b of the laminated piezoelectric actuator 22 is engaged with the recess 24a of the support plate 24. Next, the actuator receiver 34 is placed on the upper end of the actuator cover 26, and then the adjustment cap nut 33 is screwed onto the threaded portion 26c of the actuator cover 26. Through the above steps, the assembly of the actuator assembly 20 is completed.

[0033] The actuator assembly 20 is attached to the body 10 by inserting the actuator assembly 20 into the accommodating recess 15, screwing the guide member 28 into the threaded portion 15a of the accommodating recess 15, and tightening the guide member 28. The actuator assembly 20 is removed from the body 10 by loosening the guide member 28 and removing it from the body 10.

[0034] In the diaphragm valve configured as described above, the gap between the valve seat 15b and the diaphragm 40, i.e., the cross-sectional area of ​​the flow path, is controlled by controlling the voltage applied to the laminated piezoelectric actuator 22 of the actuator assembly 20. When the overall length L0 of the laminated piezoelectric actuator 22 is expanded, the actuator cover 26 moves in a direction away from the diaphragm 40 against the elastic restoring force of the disc spring 30, the gap between the valve seat 15b and the diaphragm 40 widens, and the flow rate of the fluid flowing through the flow path increases. When the voltage applied to the laminated piezoelectric actuator 22 is reduced or no voltage is applied, the actuator cover 26 moves in a direction approaching the diaphragm 40 due to the elastic restoring force of the disc spring 30, and the flow rate of the fluid flowing through the flow path decreases or becomes zero.

[0035] According to this embodiment, the actuator assembly 20 can be attached to and detached from the accommodating recess 15 of the body 10 independently of the diaphragm 40, improving ease of assembly and maintenance. In particular, the actuator assembly 20 can be removed without removing the diaphragm 40 from the body 10, so the flow path is not exposed to the atmosphere. Therefore, when the actuator assembly 20 is removed from the accommodating recess 15 and then reinstalled, there is no need to clean the inside of the flow path of the diaphragm valve.

[0036] According to this embodiment, the diaphragm 40 is fixed in the accommodating recess 15 by a fixing ring 42 that screws into the threaded portion 15a of the accommodating recess 15 of the body 10. In addition, the guide member 28 as a fixing member is screwed into the common threaded portion 15a, and the position of the support plate 24 is fixed in the accommodating recess 15 by cooperation between the guide member 28 and the fixing ring 42. Furthermore, since the inner diameter of the accommodating recess 15 of the body 10 is constant from the opening to the bottom surface, the outer diameter of the diaphragm 40 can be made large. As a result, the diaphragm valve can be made smaller while maintaining the flow rate.

[0037] According to this embodiment, the inner surface of the fixing ring 42 has a double hex structure, so that the outer diameter of the actuator cover 26 that penetrates the fixing ring 42 can be made larger than in a hex structure, and the structure of the actuator cover 26 can also be simplified.

[0038] According to this embodiment, the actuator cover 26 is made cylindrical with a constant outer diameter, and the diaphragm holder 27 is directly attached to the lower end of the actuator cover, so that the diaphragm holder 27 can accommodate the larger diameter diaphragm 40.

[0039] In this embodiment, an example has been given of a case in which a diaphragm valve is applied to a pressure type flow control device, but this is not limited to pressure type flow control devices, and the diaphragm valve of the present invention can also be applied to a flow control device equipped with a thermal type flow sensor that uses a heating resistor to measure flow rate.

[0040] In this embodiment, the diaphragm valve is used as a flow rate control valve, but it can also be used as an opening and closing valve.

[0041] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific examples, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0042] 1 Flow control device 10. Body 11,12 Flow path 15 Recessed portion 15a Threaded part 15b Valve seat 15c bottom 20 Actuator Assembly 22 Multilayer Piezoelectric Actuator 22a Casing 22b Tip 22c Proximal end 24 Support Plate 24a Recess 24b End 24d Recess 26 Actuator cover 26a Notch 26c Threaded part 26d Receiving part 26e screw hole 26f Mounting recess 28 Guide member (fixing member) 28a Threaded part 28b,28c retaining groove 28d Recess 30 Disc spring 31 Support pin 32 Spacer 33 Adjustment cap nut 34 Actuator holder 35 Lock nut 40 Diaphragm 41 Presser adapter 42 Fixing ring 42a Threaded part 42b Inner surface OR O-ring 101 Entrance block 101a Flow path 102 Exit block 110 Opening and closing valve 120,130 Pressure detector

Claims

1. A block-shaped body defining a flow path; a diaphragm provided on a bottom surface of an accommodating recess formed in the body, the diaphragm defining a part of the flow passage and changing an opening degree of the flow passage; a fixing ring that is screwed into a threaded portion formed on an inner circumferential surface of the accommodating recess to fix the diaphragm to the body; A laminated piezoelectric actuator having piezoelectric elements laminated in a cylindrical casing; a support plate for supporting the laminated piezoelectric actuator; a cylindrical actuator cover that holds a diaphragm presser and accommodates the laminated piezoelectric actuator therein while transmitting displacement caused by a piezoelectric effect of the laminated piezoelectric actuator; a fixing member that is screwed into a threaded portion common to the threaded portion and cooperates with the fixing ring to fix the position of the support plate within the accommodating recess, The inner peripheral surface of the fixing ring has a double hex structure, The actuator cover extends through the retaining ring. A diaphragm valve.

2. 2. The diaphragm valve according to claim 1, wherein the fixing member is formed in a cylindrical shape and also serves as a guide member that movably guides the actuator cover in directions approaching and moving away from the diaphragm.

3. the support plate is disposed so as to cross the actuator cover through a cutout portion formed opposite the actuator cover, and so as to have both ends protrude from an outer circumferential surface of the actuator cover; 3. The diaphragm valve according to claim 1, wherein both ends of the support plate are clamped by the fixing ring and the fixing member.

4. 4. A diaphragm valve as described in any one of claims 1 to 3, further comprising an elastic member provided inside the actuator cover and interposed between the support plate and a receiving portion formed on the actuator cover, for urging the actuator cover toward the diaphragm.

5. 5. The diaphragm valve according to claim 1, wherein the actuator cover has a constant outer diameter from one end to the other end in the longitudinal direction.

6. 5. The diaphragm valve according to claim 4, wherein the laminated piezoelectric actuator, the support plate, the actuator cover, the fixing member and the elastic member constitute an actuator assembly that is detachable from the accommodating recess independent of the diaphragm.

7. 7. A flow rate control device using the diaphragm valve according to claim 1 as a flow rate control valve for controlling a flow rate.

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