Corrugated pipe pump

Abstract

One-way valves (15, 16) of a bellows pump (10) have cylindrical valve housings (15a, 16a) in which male threads (15e, 16e) that are fastened and screwed into female thread holes (111, 112) of a pump head (11) are formed at one axial end (15d, 16d). A bellows pump (10) is provided with: engagement grooves (113, 114) provided on the bottom surfaces (111a, 112a) of female threaded holes (111, 112) of a pump head (11); and engagement sections (151, 161) which are provided at the ends (15d, 16d) of the valve housings (15a, 16a) and which engage with the inner peripheral surfaces (113a, 114a) of the engagement grooves (113, 114).

Description

Technical Field

[0001] The invention relates to a bellows pump. Background Art

[0002] In semiconductor manufacturing, chemical industry, etc., as a pump for conveying and supplying a transfer fluid such as a liquid medicine or a solvent, a bellows pump such as that described in Patent Document 1 is known. The bellows pump described in Patent Document 1 is configured in the following manner, that is, a pump housing is connected on the left and right sides of a pump head to form two air chambers, and a pair of bellows that can be extended and retracted in the left and right directions are provided inside each air chamber, and each bellows is contracted or extended by alternately supplying pressurized air to each air chamber.

[0003] The pump head is provided with an intake passage and a discharge passage for transferring fluid which are connected to the inside of each bellows. In addition, the pump head is provided with a plurality of one-way valves which allow the transfer fluid to flow in one direction relative to the intake passage or the discharge passage and prevent the transfer fluid from flowing in the other direction. Each one-way valve comprises: a valve housing; a valve body which is accommodated in the valve housing; and a spring which pre-tightens the valve body in the valve closing direction. One end of the valve housing is mounted on the pump head by screwing an external thread formed on its outer periphery into an internal thread hole formed in the pump head.

[0004] The one-way valve for the suction passage is configured such that it is opened by the extension of the bellows, thereby allowing the transfer fluid to flow from the suction passage into the bellows, and is closed by the contraction of the bellows, thereby preventing the transfer fluid from the bellows into the suction passage. In addition, the one-way valve for the discharge passage is configured such that it is closed by the extension of the bellows, thereby preventing the transfer fluid from flowing into the bellows from the discharge passage, and is opened by the contraction of the bellows, thereby allowing the transfer fluid to flow from the bellows into the discharge passage.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-003709 Summary of the invention

[0006] Regarding the bellows pump, when the valve housing of the check valve is mounted on the pump head, one end of the valve housing on the external thread side abuts against the bottom of the internal thread hole of the pump housing, and the one end of the valve housing may be deformed in a manner of tilting radially inward. If the valve housing is deformed in this way, the valve body and spring of the check valve may not move completely, the pulsation on the discharge side may worsen, and impact pressure and cavitation called "water hammer" may be generated, which may have an adverse effect on the bellows pump.

[0007] The present invention has been made in view of such circumstances, and an object of the present invention is to provide a bellows pump capable of suppressing deformation of a valve housing of a check valve.

[0008] (1) The bellows pump of the present invention comprises: a pump head, which has an intake passage and a discharge passage for transferring fluid, and is formed with an internal threaded hole with a bottom; a bellows, which is freely installed on the pump head, and sucks the transferred fluid from the intake passage into the interior by extending, and discharges the transferred fluid from the interior to the discharge passage by contracting; and a one-way valve, which allows the flow of the transferred fluid in one direction relative to the intake passage or the discharge passage, and prevents the flow of the transferred fluid in the other direction, the one-way valve comprising: a cylindrical valve housing, which has an external thread formed at an end on one axial side and is fastened and screwed into the internal threaded hole of the pump head; a snap-fitting groove, which is arranged on the bottom surface of the internal threaded hole of the pump head; and a snap-fitting portion, which is arranged at the end of the valve housing and snaps with the inner circumferential surface of the snap-fitting groove.

[0009] According to the bellows pump of the present invention, when the external thread formed at the end of the valve housing of the one-way valve is screwed into the internal thread hole of the pump head, the engaging portion provided at the end of the valve housing engages with the inner circumferential surface of the engaging groove provided at the bottom surface of the internal thread hole. When the valve housing of the one-way valve is mounted on the pump head through this engagement, the end of the valve housing can be prevented from deforming in a manner of tilting radially inward.

[0010] (2) In the bellows pump of (1) above, preferably, the inner peripheral surface of the engagement groove is a tapered surface whose diameter increases toward one side in the axial direction.

[0011] In this case, the engagement portion engages with the tapered surface of the inner peripheral surface of the engagement groove, thereby pressing and expanding the end of the valve housing radially outward, thereby improving the engagement of the external thread of the valve housing with the internal thread hole of the pump head.

[0012] Effects of the Invention

[0013] According to the bellows pump of the present invention, deformation of the valve housing of the check valve can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic configuration diagram of a bellows pump device including a bellows pump according to an embodiment of the present invention.

[0015] Figure 2 It is a cross-sectional view of a bellows pump.

[0016] Figure 3 This indicates the area around the left suction check valve. Figure 2 An enlarged cross-sectional view of the main parts.

[0017] Figure 4 This indicates the area around the left discharge check valve. Figure 2 An enlarged cross-sectional view of the main parts.

[0018] Figure 5 This is an explanatory diagram showing the operation of the bellows pump.

[0019] Figure 6 This is an explanatory diagram showing the operation of the bellows pump.

[0020] Figure 7 It is an enlarged cross-sectional view showing the periphery of the left discharge check valve of the bellows pump according to the second embodiment of the present invention.

[0021] Figure 8 It is an enlarged cross-sectional view showing the periphery of the left discharge check valve of the bellows pump according to the third embodiment of the present invention. DETAILED DESCRIPTION

[0022] Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, at least a part of each embodiment described below may be arbitrarily combined.

[0023] [First embodiment]

[0024] <Overall structure>

[0025] Figure 1 This is a schematic structural diagram of a bellows pump device 1 having a bellows pump according to a first embodiment of the present invention. The bellows pump device 1 is used, for example, to supply a certain amount of a transfer fluid such as a liquid medicine or a solvent in a semiconductor manufacturing device. The bellows pump device 1 has an air supply device (fluid supply device) 2, a mechanical regulator 3, a first electromagnetic valve 4, a second electromagnetic valve 5, a control unit 6, a bellows pump 10, a first electro-pneumatic regulator (a first fluid pressure regulating unit) 51, and a second electro-pneumatic regulator (a second fluid pressure regulating unit) 52.

[0026] The air supply device 2 is constituted by, for example, an air compressor, and generates pressurized air (pressurized fluid) to be supplied to the bellows pump 10. The mechanical regulator 3 adjusts the air pressure (fluid pressure) of the pressurized air generated by the air supply device 2. The first electro-pneumatic regulator 51 and the second electro-pneumatic regulator 52 will be described later.

[0027] Figure 2 The bellows pump 10 of this embodiment includes a pump head 11, a pair of pump housings 12, a pair of bellows, namely a first bellows 13 and a second bellows 14, a pair of suction check valves (check valves) 15, and a pair of discharge check valves (check valves) 16.

[0028] The pump head 11 is arranged at the center of the bellows pump 10. A pair of pump housings 12 are installed on the left and right sides of the pump head 11. The first bellows 13 and the second bellows 14 are installed on the left and right sides of the pump head 11 inside the pump housings 12. A pair of suction check valves 15 are installed on the left and right sides of the pump head 11 inside the first and second bellows 13 and 14, respectively. Similarly, a pair of discharge check valves 16 are installed on the left and right sides of the pump head 11 inside the first and second bellows 13 and 14, respectively.

[0029] <Bellows>

[0030] The first bellows 13 and the second bellows 14 are formed into a bottomed cylindrical shape by fluororesins such as polytetrafluoroethylene (PTFE) and tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA). The flange portion 13a formed integrally with the open side end of the first bellows 13 is pressed and fixed to the side of the pump head 11 in an airtight manner. Similarly, the flange portion 14a formed integrally with the open side end of the second bellows 14 is pressed and fixed to the side of the pump head 11 in an airtight manner. The peripheral walls of the first and second bellows 13 and 14 are formed in a corrugated shape and are configured to be able to expand and contract freely in the left and right directions independently of each other.

[0031] The working plate 19 is fixed to the outer surface of the closed side end of the first and second bellows 13, 14 by bolts 17 and nuts 18. The first and second bellows 13, 14 can be extended and retracted between a maximum extension state in which the outer surface of the working plate 19 abuts against the inner surface of the bottom wall portion 121 of the bottomed cylindrical pump housing 12 and a maximum contraction state in which the inner surface of the piston body 23 described later abuts against the outer surface of the bottom wall portion 121.

[0032] <Pump housing>

[0033] The opening peripheral edge of the pump housing 12 (hereinafter referred to as "first pump housing 12A") is pressed and fixed in an airtight manner to the flange portion 13a of the first bellows 13. Thus, a first discharge side air chamber (first discharge side fluid chamber) 21A maintained in an airtight state is formed on the outside of the first bellows 13 inside the first pump housing 12A.

[0034] The first pump housing 12A is provided with a first air intake and exhaust port 22A, and the first air intake and exhaust port 22A is connected to the air supply device 2 via the first solenoid valve 4, the first electro-pneumatic regulator 51, and the mechanical regulator 3 (see Figure 1 ). Thus, if pressurized air is supplied from the air supply device 2 to the interior of the first discharge side air chamber 21A, the first bellows 13 contracts to a predetermined contracted state (hereinafter referred to as "contracted state"). The contracted state of the first bellows 13 may be a maximum contracted state or a state immediately before reaching the maximum contracted state.

[0035] The opening peripheral edge of the pump housing 12 (hereinafter, also referred to as "second pump housing 12B") is pressed and fixed in an airtight manner to the flange portion 14a of the second bellows 14. Thus, a second discharge-side air chamber (second discharge-side fluid chamber) 21B maintained in an airtight state is formed on the outside of the second bellows 14 inside the second pump housing 12B.

[0036] The second pump housing 12B is provided with a second air intake and exhaust port 22B, and the second air intake and exhaust port 22B is connected to the air supply device 2 via the second solenoid valve 5, the second electro-pneumatic regulator 52, and the mechanical regulator 3 (see Figure 1 ). Thus, if pressurized air is supplied from the air supply device 2 to the interior of the second discharge side air chamber 21B, the second bellows 14 contracts to a predetermined contracted state (hereinafter referred to as "contracted state"). The contracted state of the second bellows 14 may be a maximum contracted state or a state immediately before reaching the maximum contracted state.

[0037] The rod-shaped connecting member 20 passes through the bottom wall 121 of each pump housing 12A, 12B. The connecting member 20 is supported on the bottom wall 121 in a manner that allows sliding in the left-right direction. The piston body 23 is fixed to the outer end of the connecting member 20 by a nut 24. The piston body 23 is supported on the inner circumferential surface of a cylindrical cylinder body 25 that is integrally provided with the outer side of the bottom wall 121 in a manner that allows sliding in the left-right direction while maintaining an airtight state.

[0038] Thus, on the first pump housing 12A side, the space surrounded by the bottom wall 121, the cylinder 25, and the piston body 23 is set as the first suction side air chamber (first suction side fluid chamber) 26A maintained in an airtight state. In addition, on the second pump housing 12B side, the space surrounded by the bottom wall 121, the cylinder 25, and the piston body 23 is set as the second suction side air chamber (second suction side fluid chamber) 26B maintained in an airtight state.

[0039] The cylinder 25 on the first pump housing 12A side is formed with an air intake and exhaust port 251 communicating with the first suction side air chamber 26A. The air intake and exhaust port 251 is connected to the air supply device 2 via the first solenoid valve 4, the first electro-pneumatic regulator 51 and the mechanical regulator 3 (see Figure 1 ). Thus, if pressurized air is supplied from the air supply device 2 to the interior of the first suction side air chamber 26A via the air intake and exhaust port 251, the first bellows 13 is extended to a predetermined extended state (hereinafter referred to as "extended state"). The extended state of the first bellows 13 may be a maximum extended state or a state immediately before reaching the maximum extended state.

[0040] The cylinder 25 on the second pump housing 12B side is formed with an air intake and exhaust port 252 communicating with the second suction side air chamber 26B. The air intake and exhaust port 252 is connected to the air supply device 2 via the second solenoid valve 5, the second electro-pneumatic regulator 52 and the mechanical regulator 3 (see Figure 1 ). Thus, if pressurized air is supplied from the air supply device 2 to the interior of the second suction side air chamber 26B via the air intake and exhaust port 252, the second bellows 14 is extended to a predetermined extended state (hereinafter referred to as "extended state"). The extended state of the second bellows 14 may be the maximum extended state or the state immediately before reaching the maximum extended state.

[0041] According to the above structure, the first pump housing 12A having the first discharge side air chamber 21A formed therein, the piston body 23 and the cylinder body 25 forming the first suction side air chamber 26A constitute the first drive unit 27 that allows the first bellows 13 to continuously perform a telescopic action between the extended state and the contracted state. In addition, the second pump housing 12B having the second discharge side air chamber 21B formed therein, the piston body 23 and the cylinder body 25 forming the second suction side air chamber 26B constitute the second drive unit 28 that allows the second bellows 14 to continuously perform a telescopic action between the extended state and the contracted state.

[0042] Furthermore, the first driving unit 27 and the second driving unit 28 are driven by pressurized air, but may be driven by other fluids.

[0043] <Testing Department>

[0044] A proximity sensor 29A and a proximity sensor 29B are mounted on the cylinder 25 of the first drive unit 27. A detection plate 30 detected by the proximity sensors 29A and 29B is mounted on the piston body 23 of the first drive unit 27. The detection plate 30 reciprocates with the piston body 23 and approaches the proximity sensors 29A and 29B alternately.

[0045] The proximity sensor 29A is configured to detect the position of the detected plate 30 when the first bellows 13 is in a contraction midway state before it changes to a contraction state. The proximity sensor 29B is configured to detect the position of the detected plate 30 when the first bellows 13 is in an extension state. If each of the proximity sensors 29A and 29B detects the detected plate 30, the detection signal is output to the control unit 6. The pair of proximity sensors 29A and 29B functions as the first detection unit 29 for detecting the extension and contraction state of the first bellows 13.

[0046] A proximity sensor 31A and a proximity sensor 31B are mounted on the cylinder 25 of the second drive unit 28. A detected plate 32 detected by the proximity sensors 31A and 31B is mounted on the piston body 23 of the second drive unit 28. The detected plate 32 reciprocates with the piston body 23 and alternately approaches the proximity sensors 31A and 31B.

[0047] The proximity sensor 31A is configured to detect the position of the detected plate 32 when the second bellows 14 is in the mid-contraction state before it changes to the contraction state. The proximity sensor 31B is configured to detect the position of the detected plate 32 when the second bellows 14 is in the extension state. If each proximity sensor 31A, 31B detects the detected plate 30, the detection signal is output to the control unit 6. The pair of proximity sensors 31A, 31B functions as the second detection unit 31 that detects the extension and contraction state of the second bellows 14.

[0048] Here, the "mid-contraction state" of the first bellows 13 (the second bellows 14) means that the contraction passing position of the first bellows 13 (the second bellows 14) is closer to the contraction end position (contracted state) than the contraction start position (extended state). More specifically, it means that the first bellows 13 (the second bellows 14) contracts to a position of 50% to 90% of the contraction length from the extended state to the contracted state.

[0049] In addition, the first detection unit 29 is composed of proximity sensors 29A and 29B, but is not limited to this, and can be composed of, for example, a displacement sensor using lasers, etc. Similarly, the second detection unit 31 is composed of proximity sensors 31A and 31B, but is not limited to this, and can be composed of, for example, a displacement sensor using lasers, etc.

[0050] <Pump head>

[0051] The pump head 11 is formed of a fluororesin such as PTFE or PFA. An intake passage 34 and an exhaust passage 35 for transferring a fluid are formed inside the pump head 11. The intake passage 34 opens on the outer peripheral surface of the pump head 11 and is connected to an intake port (not shown) provided on the outer peripheral surface. The intake port is connected to a storage container or the like for transferring a fluid. The exhaust passage 35 opens on the outer peripheral surface of the pump head 11 and is connected to an exhaust port (not shown) provided on the outer peripheral surface. The exhaust port is connected to a transfer destination of the transferred fluid.

[0052] The suction passage 34 branches toward the left and right sides inside the pump head 11, and has a suction port 36 opened on the left and right sides of the pump head 11. Each suction port 36 is connected to the inside of the bellows 13 and 14 via the suction check valve 15. The discharge passage 35 branches toward the left and right sides inside the pump head 11, and has a discharge port 37 opened on the left and right sides of the pump head 11. Each discharge port 37 is connected to the inside of the bellows 13 and 14 via the discharge check valve 16.

[0053] <Check valve>

[0054] Figure 3 The left side suction check valve 15 is shown around Figure 2 An enlarged cross-sectional view of the main part. Figure 2 and Figure 3 In the embodiment, a bottomed internal threaded hole 111 is formed on each of the left and right side walls of the pump head 11. The suction port 36 of the suction passage 34 opens at the bottom surface 111a of each internal threaded hole 111. Each internal threaded hole 111 is formed concentrically with the suction port 36. A suction check valve 15 is provided in each internal threaded hole 111 of the pump head 11.

[0055] The suction check valve 15 includes a valve housing 15a, a valve body 15b, and a spring 15c. The valve housing 15a is formed in a cylindrical shape. An external thread 15e is formed on the outer periphery of an end 15d on one axial side of the valve housing 15a. The external thread 15e of the valve housing 15a is screwed into the internal thread hole 111 of the pump head 11. Thus, the end 15d on one axial side of the valve housing 15a is mounted on the pump head 11.

[0056] An engaging groove 113 is formed on the bottom surface 111a of each internal threaded hole 111 of the pump head 11. The engaging groove 113 is formed in a circular ring shape concentric with the suction port 36 on the radial outer side of the suction port 36 of the bottom surface 111a. The engaging groove 113 is formed in a substantially concave shape in a manner of being recessed from the bottom surface 111a to one axial side when viewed in section. In addition, the inner circumferential surface 113a of the engaging groove 113 is a linear tapered surface that expands in diameter as it moves from the other axial side to one axial side when viewed in section. The outer circumferential surface 113b of the engaging groove 113 is a circular surface that extends straight in the axial direction when viewed in section. The outer diameter of the engaging groove 113 (the diameter of the outer circumferential surface 113b) is the same as the inner diameter of the internal threaded hole 111.

[0057] The end 15d of the valve housing 15a is provided with an engaging portion 151 that engages with the engaging groove 113 of the pump head 11. The engaging portion 151 of the present embodiment is formed in an annular shape over the entire circumference of the end 15d of the valve housing 15a. The engaging portion 151 is formed in an approximately convex shape in a manner that protrudes from the end 15d to one side in the axial direction when viewed in section. The inner circumferential surface 151a of the engaging portion 151 is a linear tapered surface that expands along the inner circumferential surface (tapered surface) 113a of the engaging groove 113 when viewed in section. The outer circumferential surface 151b of the engaging portion 151 is a linear tapered surface that decreases in diameter as it moves from the other axial side to one axial side. The maximum outer diameter of the engaging portion 151 (the maximum diameter of the outer circumferential surface 151b) is substantially the same as the outer diameter of the engaging groove 113 (the diameter of the outer circumferential surface 113b).

[0058] As described above, the inner circumferential surface 151a of the engagement portion 151 is engaged with the inner circumferential surface 113a of the engagement groove 113. In addition, an annular space S1 is formed between the outer circumferential surface 151b of the engagement portion 151 and the outer circumferential surface 113b of the engagement groove 113. The space S1 functions as a space for the engagement portion 151 to escape radially outward when the inner circumferential surface 151a of the engagement portion 151 is engaged with the inner circumferential surface 113a of the engagement groove 113.

[0059] The valve body 15b of the suction check valve 15 is provided in the valve housing 15a so as to be capable of closing the valve in the valve closing direction ( Figure 3 The axial direction) and the valve opening direction ( Figure 3 The spring 15c is composed of, for example, a compression coil spring and is housed in the valve housing 15a. The spring 15c preloads the valve body 15b in the valve closing direction. The valve body 15b closes the suction port 36 (closes the valve) by the preload force of the spring 15c, and opens the suction port 36 (opens the valve) if back pressure due to the flow of the transfer fluid accompanying the expansion and contraction of the bellows 13 and 14 acts.

[0060] Thus, the suction check valve 15 opens when the bellows 13, 14 equipped with it are extended, allowing the transfer fluid to be sucked from the suction passage 34 in the direction (one direction) toward the inside of the bellows 13, 14. In addition, the suction check valve 15 closes when the bellows 13, 14 equipped with it are contracted, preventing the transfer fluid from flowing back from the inside of the bellows 13, 14 in the direction (the other direction) toward the suction passage 34.

[0061] In addition, the right-side suction one-way valve 15 and the corresponding snap-fitting portion 151 and snap-fitting groove 113 are formed symmetrically with respect to the above-mentioned left-side suction one-way valve 15 and the corresponding snap-fitting portion 151 and snap-fitting groove 113 across the center line X in the left-right direction of the pump head 11.

[0062] Figure 4The left side discharge check valve 16 is shown around Figure 2 An enlarged cross-sectional view of the main part. Figure 2 and Figure 4 In the embodiment, a bottomed internal threaded hole 112 is formed on each of the left and right side walls of the pump head 11. The discharge port 37 of the discharge passage 35 opens at the bottom surface 112a of each internal threaded hole 112. Each internal threaded hole 112 is formed concentrically with the discharge port 37. A discharge check valve 16 is provided in each internal threaded hole 112 of the pump head 11.

[0063] The discharge check valve 16 has a valve housing 16a, a valve body 16b and a spring 16c. The valve housing 16a is formed in a cylindrical shape. An external thread 16e is formed on the outer periphery of an end 16d on one axial side of the valve housing 16a. The external thread 16e of the valve housing 16a is screwed into the internal thread hole 112 of the pump head 11. Thus, the end 16d on one axial side of the valve housing 16a is mounted on the pump head 11.

[0064] An engaging groove 114 is formed on the bottom surface 112a of each internal threaded hole 112 of the pump head 11. The engaging groove 114 is formed in a concentric annular shape with the discharge port 37 on the radial outer side of the discharge port 37 of the bottom surface 112a. The engaging groove 114 is formed in a substantially concave shape in a manner of being recessed from the bottom surface 112a to one axial side when viewed in section. In addition, the inner circumferential surface 114a of the engaging groove 114 is a linear conical surface that expands in diameter as it moves from the other axial side to one axial side when viewed in section. The outer circumferential surface 114b of the engaging groove 114 is a circumferential surface that extends straight in the axial direction when viewed in section. The outer diameter of the engaging groove 114 (the diameter of the outer circumferential surface 114b) is the same as the inner diameter of the internal threaded hole 112.

[0065] The end 16d of the valve housing 16a is provided with an engaging portion 161 that engages with the engaging groove 114 of the pump head 11. The engaging portion 161 of the present embodiment is formed in an annular shape over the entire circumference of the end 16d of the valve housing 16a. The engaging portion 161 is formed in an approximately convex shape in a manner that protrudes from the end 16d to one side in the axial direction when viewed in section. The inner circumferential surface 161a of the engaging portion 161 is a linear tapered surface that expands along the inner circumferential surface (tapered surface) 114a of the engaging groove 114 when viewed in section. The outer circumferential surface 161b of the engaging portion 161 is a linear tapered surface that decreases in diameter as it moves from the other axial side to one axial side. The maximum outer diameter of the engaging portion 161 (the maximum diameter of the outer circumferential surface 161b) is substantially the same as the outer diameter of the engaging groove 114 (the diameter of the outer circumferential surface 114b).

[0066] As described above, the inner circumferential surface 161a of the engagement portion 161 is engaged with the inner circumferential surface 114a of the engagement groove 114. In addition, an annular space S2 is formed between the outer circumferential surface 161b of the engagement portion 161 and the outer circumferential surface 114b of the engagement groove 114. The space S2 functions as a space for the engagement portion 161 to escape radially outward when the inner circumferential surface 161a of the engagement portion 161 and the inner circumferential surface 114a of the engagement groove 114 are engaged.

[0067] The valve body 16b of the discharge check valve 16 is provided in the valve housing 16a so as to be capable of closing the valve in the valve closing direction ( Figure 4 The axial direction) and the valve opening direction ( Figure 4 The spring 16c is composed of, for example, a compression coil spring and is housed in the valve housing 16a. The spring 16c preloads the valve body 16b in the valve closing direction. The valve body 16b closes the opening 16f on the other axial side of the valve housing 16a by the preload force of the spring 16c (valve closing). If the back pressure generated by the flow of the transfer fluid accompanying the expansion and contraction of the bellows 13 and 14 acts, the opening 16f is opened (valve opening).

[0068] Thus, the discharge check valve 16 opens when the bellows 13, 14 in which it is arranged contracts, allowing the transfer fluid to flow out from the inside of the bellows 13, 14 in the direction (one direction) toward the discharge passage 35. In addition, the discharge check valve 16 closes when the bellows 13, 14 in which it is arranged extends, preventing the transfer fluid from flowing back from the discharge passage 35 in the direction (the other direction) toward the inside of the bellows 13, 14.

[0069] In addition, the right-side discharge one-way valve 16 and the corresponding engaging portion 161 and engaging groove 114 are formed symmetrically with respect to the left-side discharge one-way valve 16 and the corresponding engaging portion 151 and engaging groove 114 across the center line X in the left-right direction of the pump head 11.

[0070] <Bellows Pump Operation>

[0071] Next, refer to Figure 5 and Figure 6 The operation of the bellows pump 10 of this embodiment will be described. Figure 5 and Figure 6 In FIG. 1 , the structures of the first and second bellows 13 and 14 are simplified. Figure 5As shown, when the first bellows 13 contracts and the second bellows 14 extends, the valve bodies 15b and 16b of the suction check valve 15 and the discharge check valve 16 installed on the left side of the pump head 11 are respectively moved to the right side of the valve housings 15a and 16a in the figure due to the pressure from the transfer fluid in the first bellows 13. As a result, the suction check valve 15 is closed and the discharge check valve 16 is opened, and the transfer fluid in the first bellows 13 is discharged from the discharge passage 35 to the outside of the pump.

[0072] On the other hand, the valve body 15b of the suction check valve 15 mounted on the right side of the pump head 11 in the figure moves to the right side of the valve housing 15a in the figure by the suction action of the second bellows 14. The valve body 16b of the discharge check valve 16 mounted on the right side of the pump head 11 in the figure moves to the right side of the valve housing 16a in the figure by the suction action of the second bellows 14 and the pressing action of the transfer fluid discharged from the first bellows 13 to the discharge passage 35. As a result, the suction check valve 15 opens, and the discharge check valve 16 closes, and the transfer fluid is sucked from the suction passage 34 into the second bellows 14.

[0073] Next, if Figure 6 As shown, when the first bellows 13 is extended and the second bellows 14 is contracted, the valve bodies 15b and 16b of the suction check valve 15 and the discharge check valve 16 installed on the right side of the pump head 11 in the figure are moved to the left side of the figure of the valve housings 15a and 16a by the pressure from the transfer fluid in the second bellows 14. As a result, the suction check valve 15 is closed and the discharge check valve 16 is opened, and the transfer fluid in the second bellows 14 is discharged from the discharge passage 35 to the outside of the pump.

[0074] On the other hand, the valve body 15b of the suction check valve 15 installed on the left side of the pump head 11 in the figure moves to the left side of the valve housing 15a in the figure by the suction action of the first bellows 13. The valve body 16b of the discharge check valve 16 installed on the left side of the pump head 11 in the figure moves to the left side of the valve housing 16a in the figure by the suction action of the first bellows 13 and the pressing action of the transfer fluid discharged from the first bellows 13 to the discharge passage 35. As a result, the suction check valve 15 is opened, and the discharge check valve 16 is closed, and the transfer fluid is sucked into the first bellows 13 from the suction passage 34.

[0075] By repeating the above-mentioned operation, the left and right bellows 13 and 14 can alternately perform suction and discharge of the transfer fluid.

[0076] <Solenoid valve>

[0077] exist Figure 1In the embodiment, the first electromagnetic valve 4 is composed of, for example, a three-way electromagnetic switching valve having a pair of solenoids 4a and 4b. Each solenoid 4a, 4b is excited based on a command signal received from the control unit 6. Thus, the first electromagnetic valve 4 is switched and controlled by the control unit 6. The first electromagnetic valve 4 switches the supply and discharge of pressurized air to the first discharge side air chamber 21A and the supply and discharge of pressurized air to the first suction side air chamber 26A at the first drive unit 27.

[0078] Specifically, when the solenoid 4a is excited, the first solenoid valve 4 switches to a state where pressurized air is supplied to the first discharge side air chamber 21A and the pressurized air in the first suction side air chamber 26A is discharged. Also, when the solenoid 4b is excited, the first solenoid valve 4 switches to a state where the pressurized air in the first discharge side air chamber 21A is discharged and the pressurized air is supplied to the first suction side air chamber 26A.

[0079] The second electromagnetic valve 5 is composed of, for example, a three-way electromagnetic switching valve having a pair of solenoids 5a and 5b. Each solenoid 5a, 5b receives a command signal from the control unit 6 and is excited. Thus, the second electromagnetic valve 5 is switched and controlled by the control unit 6. The second electromagnetic valve 5 switches the supply and discharge of pressurized air to the second discharge side air chamber 21B and the supply and discharge of pressurized air to the second suction side air chamber 26B in the second drive unit 28.

[0080] Specifically, when the solenoid 5a is excited, the second electromagnetic valve 5 switches to a state where pressurized air is supplied to the second discharge side air chamber 21B and the pressurized air in the second suction side air chamber 26B is discharged. Also, when the solenoid 5b is excited, the second electromagnetic valve 5 switches to a state where the pressurized air in the second discharge side air chamber 21B is discharged and the pressurized air is supplied to the second suction side air chamber 26B. In addition, the first and second electromagnetic valves 4 and 5 of the present embodiment are composed of three-way electromagnetic switching valves, but may also be two-way electromagnetic switching valves without a neutral position.

[0081] <Electro-pneumatic regulator>

[0082] The first electro-pneumatic regulator 51 is disposed between the mechanical regulator 3 and the first solenoid valve 4. The first electro-pneumatic regulator 51 adjusts the air pressure of the compressed air supplied to the first suction-side air chamber 26A of the first drive unit 27 and the air pressure of the compressed air supplied to the first discharge-side air chamber 21A of the first drive unit 27.

[0083] The second electro-pneumatic regulator 52 is disposed between the mechanical regulator 3 and the second solenoid valve 5. The second electro-pneumatic regulator 52 adjusts the air pressure of the compressed air supplied to the second suction-side air chamber 26B of the second drive unit 28 and the air pressure of the compressed air supplied to the second discharge-side air chamber 21B of the second drive unit 28.

[0084] In addition, it is sufficient that the electric pneumatic regulators 51 and 52 adjust the air pressure of the pressurized air supplied to at least the suction side air chambers 26A and 26B. In addition, in the present embodiment, the electric pneumatic regulators 51 and 52 that directly adjust the air pressure are used as the fluid pressure regulating unit, but the air pressure can be indirectly adjusted by using an air flow regulating valve that adjusts the air flow, or by using an instrument that adjusts the pressure or flow of a gas (such as nitrogen) or a liquid other than air.

[0085] <Control Department>

[0086] exist Figure 1 and Figure 2 In the embodiment, the control unit 6 is configured to include a computer including a CPU and the like. The functions of the control unit 6 are performed by the CPU executing a control program stored in a storage device of the computer. The control unit 6 switches the first electromagnetic valve 4 and the second electromagnetic valve 5 based on the detection results of the first detection unit 29 and the second detection unit 31, thereby performing drive control of the first drive unit 27 and the second drive unit 28.

[0087] Specifically, the control unit 6 controls the drives of the first drive unit 27 and the second drive unit 28 based on the detection results of the first detection unit 29 and the second detection unit 31 in the following manner, i.e., the second bellows 14 is contracted from the extended state before the first bellows 13 is about to become the contracted state, and the first bellows 13 is contracted from the extended state before the second bellows 14 is about to become the contracted state.

[0088] The control unit 6 performs drive control in the above manner, so that at the timing when one of the first bellows 13 and the second bellows 14 switches from contraction to extension (from discharge to suction of the transfer fluid), the other bellows has already contracted and discharged the transfer fluid, thereby reducing the situation where the discharge pressure of the transfer fluid at the timing is greatly reduced. As a result, the pulsation on the discharge side of the bellows pump 10 can be reduced.

[0089] In addition, the control unit 6 can control the driving of the first cylinder 41 and the second cylinder 42 in such a manner that after one of the first bellows 13 and the second bellows 14 is in a contracted state, the other bellows 14 (bellows 13) is contracted from an extended state. In addition, the bellows pump 10 has an engaging portion 151 and an engaging groove 113 corresponding to the suction check valve 15 (see Figure 3 ) and the engaging portion 161 and the engaging groove 114 corresponding to the discharge check valve 16 (see Figure 4 ) may also only have a snap-fitting portion and a snap-fitting groove corresponding to any one of the one-way valves 15 and 16.

[0090] <Function and Effect of the Present Embodiment>

[0091] As described above, according to the bellows pump 10 of the first embodiment, when the external threads 15e, 16e of the valve housings 15a, 16a of the check valves 15, 16 are screwed into the internal threaded holes 111, 112 of the pump head 11, the engaging portions 151, 161 provided at the ends 15d, 16d of the valve housings 15a, 16a engage with the inner circumferential surfaces 113a, 114a of the engaging grooves 113, 114 formed at the bottom surfaces 111a, 112a of the internal threaded holes 111, 112. When the valve housings 15a, 16a of the check valves 15, 16 are mounted on the pump head 11 by this engagement, the ends 15d, 16d of the valve housings 15a, 16a are prevented from being deformed in a manner of tilting inward in the radial direction.

[0092] The inner circumferential surfaces 113a and 114a of the engagement grooves 113 and 114 are tapered surfaces that expand in diameter as they move toward one side in the axial direction. Therefore, the engagement portions 151 and 161 engage with the tapered surfaces (inner circumferential surfaces) 113a and 114a to expand the ends 15d and 16d of the valve housings 15a and 16a radially outward. As a result, the engagement of the external threads 15e and 16e of the valve housings 15a and 16a with respect to the internal threaded holes 111 and 112 of the pump head 11 can be improved.

[0093] Annular spaces S1 and S2 are formed between the outer circumferential surfaces 151b and 161b of the engaging portions 151 and 161 and the outer circumferential surfaces 113b and 114b of the engaging grooves 113 and 114. Therefore, when the inner circumferential surfaces 151a and 161a of the engaging portions 151 and 161 are engaged with the inner circumferential surfaces 113a and 114a of the engaging grooves 113 and 114, the engaging portions 151 and 161 can be moved radially outward within the spaces S1 and S2. Thus, the end portions 15d and 16d of the valve housings 15a and 16a can be reliably pressed and expanded radially outward.

[0094] [Second embodiment]

[0095] Figure 7 This is an enlarged cross-sectional view showing the periphery of the discharge check valve 16 on the left side of the bellows pump 10 according to the second embodiment of the present invention. In the second embodiment, the cross-sectional shapes of the engagement groove 114 of the pump head 11 and the engagement portion 161 of the discharge check valve 16 are different from those in the first embodiment.

[0096] The engagement groove 114 of the pump head 11 of the present embodiment is formed into a concave arc shape in a manner of being recessed from the bottom surface 112a of the internal threaded hole 112 to one side in the axial direction when viewed in section. The inner peripheral surface 114a of the engagement groove 114, which is closer to the radial inner side (discharge port 37 side) than the lowest point 114c, is a curved conical surface that expands in diameter from the other axial side to the one axial side when viewed in section. The outer peripheral surface 114b of the engagement groove 114, which is closer to the radial outer side than the lowest point 114c, is a curved conical surface that expands in diameter from one axial side to the other axial side when viewed in plan.

[0097] The engaging portion 161 provided at the end 16d of the valve housing 16a of the discharge check valve 16 is formed into a convex arc shape in a cross-sectional view so as to protrude from the end 16d to one side in the axial direction. The inner peripheral surface 161a of the engaging portion 161, which is closer to the radial inner side (discharge port 37 side) than the top point 161c, is a curved tapered surface that expands in diameter from the other side in the axial direction to the one side in the axial direction in the cross-sectional view. The outer peripheral surface 161b of the engaging portion 161, which is closer to the radial outer side than the top point 161c, is a curved tapered surface that expands in diameter from one side in the axial direction to the other side in the axial direction in the cross-sectional view.

[0098] The curvature radius R2 of the convex arc section of the engaging portion 161 is smaller than the curvature radius R1 of the concave arc section of the engaging groove 114. In addition, the center point C2 of the convex arc section of the engaging portion 161 is located radially inward (toward the discharge port 37) than the center point C1 of the concave arc section of the engaging groove 114.

[0099] As described above, the inner circumferential surface 161a of the engagement portion 161 engages with the inner circumferential surface 114a of the engagement groove 114. In addition, an annular space S2 is formed between the outer circumferential surface 161b of the engagement portion 161 and the outer circumferential surface 114b of the engagement groove 114. The space S2 functions as a space for the engagement portion 161 to escape radially outward when the inner circumferential surface 161a of the engagement portion 161 engages with the inner circumferential surface 114a of the engagement groove 114.

[0100] The other structures of the second embodiment are the same as those of the first embodiment, so the same reference numerals are given and their description is omitted. The bellows pump 10 of the second embodiment can also achieve the same effects as those of the first embodiment. In addition, in the second embodiment, the cross-sectional shapes of the engaging portion 161 of the discharge one-way valve 16 and the engaging groove 114 engaged with the engaging portion 161 are formed into a convex arc shape and a concave arc shape, respectively, but the cross-sectional shapes of the engaging portion 151 of the suction one-way valve 15 and the engaging groove 113 engaged with the engaging portion 151 can also be formed into a convex arc shape and a concave arc shape, respectively, in the same manner as the engaging portion 161 and the engaging groove 114.

[0101] [Third Embodiment]

[0102] Figure 8 This is an enlarged cross-sectional view showing the periphery of the discharge check valve 16 on the left side of the bellows pump 10 according to the third embodiment of the present invention. In the third embodiment, the cross-sectional shapes of the engagement groove 114 of the pump head 11 and the engagement portion 161 of the discharge check valve 16 are different from those of the first and second embodiments.

[0103] The engagement groove 114 of the pump head 11 of the present embodiment is formed into a concave shape in a manner of being recessed from the bottom surface 112a of the internal threaded hole 112 to one side in the axial direction when viewed in section. The inner peripheral surface 114a and the outer peripheral surface 114b of the engagement groove 114 are respectively circumferential surfaces extending straightly in the axial direction when viewed in section. The outer diameter of the engagement groove 114 (the diameter of the outer peripheral surface 114b) is smaller than the inner diameter of the internal threaded hole 112.

[0104] The engaging portion 161 provided at the end 16d of the valve housing 16a of the discharge check valve 16 is formed into a convex shape in a manner protruding from the end 16d to one side in the axial direction when viewed in section. The inner circumferential surface 161a and the outer circumferential surface 161b of the engaging portion 161 are respectively circumferential surfaces extending straightly in the axial direction when viewed in section. The inner diameter of the engaging portion 161 (the diameter of the inner circumferential surface 161a) is substantially the same as the inner diameter of the engaging groove 114 (the diameter of the inner circumferential surface 114a). The outer diameter of the engaging portion 161 (the diameter of the outer circumferential surface 161b) is substantially the same as the outer diameter of the engaging groove 114 (the diameter of the outer circumferential surface 114b). Thus, the inner circumferential surface 161a and the outer circumferential surface 161b of the engaging portion 161 are respectively engaged with the inner circumferential surface 114a and the outer circumferential surface 114b of the engaging groove 114.

[0105] The other structures of the third embodiment are the same as those of the first embodiment, and thus the same reference numerals are used and their description is omitted. With respect to the bellows pump 10 of the third embodiment, the engaging portion 161 provided at the end 16d of the valve housing 16a engages with the inner circumferential surface 114a of the engaging groove 114 formed at the bottom surface 112a of the internal threaded hole 112. When the valve housing 16a of the one-way valve 16 is mounted on the pump head 11 by this engagement, the end 16d of the valve housing 16a can be prevented from deforming in a manner of tilting radially inward.

[0106] In addition, in the third embodiment, the cross-sectional shapes of the engaging portion 161 of the discharge one-way valve 16 and the engaging groove 114 engaged with the engaging portion 161 are respectively formed as convex and concave, but the cross-sectional shapes of the engaging portion 151 of the suction one-way valve 15 and the engaging groove 113 engaged with the engaging portion 151 can also be formed as convex and concave, respectively, in the same way as the engaging portion 161 and the engaging groove 114.

[0107] [other]

[0108] The bellows pump 10 of each embodiment described above is not limited to use in semiconductor manufacturing equipment. In addition, the bellows pump 10 has a pair of bellows 13, 14, but may also have only a single bellows. For example, it may be a bellows pump in which one of the pair of bellows is replaced with an accumulator.

[0109] The engaging portions 151 and 161 in the above-described embodiments are provided over the entire circumference of the end portions 15d and 16d of the valve housings 15a and 16a, but may be provided only at a portion of the circumferential direction of the end portions 15d and 16d.

[0110] The spaces S1, S2 between the outer circumferential surfaces 151b, 161b of the engaging portions 151, 161 and the outer circumferential surfaces 113b, 114b of the engaging grooves 113, 114 in the above-mentioned embodiments are formed by forming the outer circumferential surfaces 151b, 161b of the engaging portions 151, 161 into conical surfaces, but the outer circumferential surfaces 151b, 161b may also be formed as circular surfaces extending straight along the axial direction, so that a conical surface that expands radially outwardly than the circular surface is formed as the outer circumferential surfaces 113b, 114b of the engaging grooves 113, 114, thereby forming the spaces S1, S2.

[0111] The embodiments disclosed this time are examples in all aspects and should be understood to be non-limiting. The scope of the present invention is indicated not by the above meaning but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0112] Description of the label

[0113] 10 Bellows Pump

[0114] 11 Pump head

[0115] 13. 1st bellows (bellows)

[0116] 14. 2nd bellows (bellows)

[0117] 15 Check valve for suction (check valve)

[0118] 15a Valve housing

[0119] 15d End

[0120] 15e External thread

[0121] 16 Discharge check valve (check valve)

[0122] 16a Valve housing

[0123] 16d End

[0124] 16e External thread

[0125] 34 Inhalation pathway

[0126] 35 Exhaust channel

[0127] 111 Internal thread hole

[0128] 111a Bottom

[0129] 112 Internal thread hole

[0130] 112a Bottom

[0131] 113 snap-in slot

[0132] 113a Inner circumference (conical surface)

[0133] 114 snap-in slot

[0134] 114a Inner circumference (conical surface)

[0135] 151 snap-fit ​​part

[0136] 161 snap-fit ​​part

Claims

1. A bellows pump, wherein: The bellows pump has: A pump head having a suction passage and a discharge passage for transferring fluid, and formed with a bottomed internal threaded hole; a bellows which is installed on the pump head in a telescopic manner, and sucks the transfer fluid from the suction passage into the interior by extending, and discharges the transfer fluid from the interior to the discharge passage by contracting; as well as a one-way valve that allows the flow of the transfer fluid in one direction and blocks the flow of the transfer fluid in the other direction with respect to the suction passage or the discharge passage, The one-way valve has: A cylindrical valve housing, wherein an outer thread is formed at an end portion on one axial side thereof and is fastened and screwed into the inner thread hole of the pump head; a snap-fit ​​groove, which is disposed on the bottom surface of the internal threaded hole of the pump head; and The engaging portion is provided at the end portion of the valve housing and engages with the inner peripheral surface of the engaging groove.

2. The bellows pump according to claim 1, wherein: The inner peripheral surface of the engagement groove is a tapered surface whose diameter increases toward one side in the axial direction.

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