Bellows pump device

Abstract

The control section 6 of the bellows pump device 1 determines whether the second bellows 14 (first bellows 13) is in a prescribed extended state when the first bellows 13 (second bellows 14) is contracted to an intermediate state of contraction based on each detection signal of the first detection section 29 and the second detection section 31, and in the case where the determination result is negative, performs next time pressure increase control of the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) in a manner such that the air pressure of the pressurized air supplied to the second suction side air chamber 26B (first suction side air chamber 26A) of the second drive section 28 (first drive section 27) is increased at the time of next extension of the second bellows 14 (first bellows 13).

Description

Technical Field

[0001] This invention relates to a bellows pump device. Background Technology

[0002] In semiconductor manufacturing, chemical industry, and other fields, bellows pumps used for conveying fluids such as pharmaceutical solutions and solvents are known to have the following structure: a pair of bellows that extend and retract independently to draw in and discharge fluid relative to their interior; and a pair of cylinders that extend and retract each bellows by supplying and discharging pressurized air (see, for example, Patent Document 1). The bellows pump described in Patent Document 1 controls the drive of each cylinder in such a way that one bellows retracts from its maximum extension state just before the other bellows reaches its maximum contraction (end of discharge) to discharge the fluid.

[0003] By controlling the drive of each cylinder in the manner described above, at the precise time when one bellows switches from contraction to extension (from discharging to drawing in the transferred fluid), another bellows is already in a state of contraction and discharging the transferred fluid. This reduces the phenomenon of a significant drop in the discharge pressure of the transferred fluid at the specified timing, thus weakening the pulsation on the discharge side of the bellows pump.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2004-293502 Summary of the Invention

[0005] Regarding the aforementioned bellows pump, until one bellows is about to reach its maximum contraction (end of discharge), the other bellows needs to be extended to its maximum extent (end of suction) beforehand. However, if the ambient temperature, the flow rate of the transferred fluid, etc., change, the stiffness of the bellows will vary accordingly. If the stiffness of the bellows changes, the extension time of the bellows (suction time) will change, causing various problems.

[0006] For example, if one bellows stiffens, the other bellows becomes difficult to extend, thus prolonging its extension time. Consequently, the other bellows cannot extend to its maximum extent until one bellows is about to reach its maximum contraction, resulting in worse pulsation on the discharge side of the bellows pump.

[0007] Furthermore, if the other bellows softens, it will easily elongate, thus shortening its elongation time. This accelerates the elongation of the other bellows, creating negative pressure inside it. This negative pressure generates a shock pressure known as "water hammer" or cavitation in the suction piping that draws the fluid into the other bellows, potentially adversely affecting semiconductor manufacturing processes.

[0008] To prevent the aforementioned problems, the air pressure supplied to the air chamber of the corresponding cylinder needs to be reset to an appropriate value so that the bellows extension time reaches an appropriate duration. However, with the current bellows pump, the air pressure needs to be manually reset each time the bellows extension time changes.

[0009] The present invention was made in view of this situation, and its object is to provide a bellows pump device that can automatically reset the fluid pressure of the pressurizing fluid used to extend the bellows when the elongation time of the bellows changes.

[0010] (1) The present invention is a bellows pump device comprising: a pair of bellows, which are independently and freely extendable and retractable, drawing in a transfer fluid by extending and discharging the transfer fluid from the interior by contracting; a pair of drive units, each having an intake-side fluid chamber and an exhaust-side fluid chamber, supplying pressurized fluid to the intake-side fluid chamber to extend each bellows to a predetermined extended state, and supplying pressurized fluid to the exhaust-side fluid chamber to contract each bellows to a predetermined contracted state; and a control unit that drives the pair of drive units in such a way that one bellows contracts from the extended state just before it is about to enter the contracted state, wherein... The bellows pump device includes: a pair of detection units that detect the expansion and contraction states of each bellows; and a pair of fluid pressure adjustment units that adjust the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of each drive unit. The control unit, based on the detection signals of each of the pair of detection units, determines whether the other bellows is in the extended state when one bellows contracts to a state just before it enters the contracted state. If the determination result is negative, the control unit performs the next pressurization control of the fluid pressure adjustment unit corresponding to the drive unit that extends the other bellows, in a manner that increases the fluid pressure when the other bellows extends again.

[0011] Regarding the bellows pump device of the present invention, when one bellows is contracted to its mid-contraction state, sometimes the other bellows does not extend to the predetermined extension state. This is because the other bellows stiffens, causing its extension time to increase. In this case, the control unit performs a next pressurization control to increase the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of the corresponding drive unit during the next extension of the other bellows. Therefore, when the extension time of the other bellows is prolonged, the fluid pressure of the pressurized fluid used to extend the other bellows can be automatically reset to a higher value. As a result, the extension time of the other bellows is shortened in the next instance, thus suppressing the worsening of pulsation on the discharge side of the bellows pump device caused by its prolonged extension time.

[0012] (2) According to other viewpoints, the present invention is a bellows pump device comprising: a pair of bellows, which are independently and freely extendable and retractable, drawing in transfer fluid into the interior by extending and discharging transfer fluid from the interior by contracting; a pair of drive units, each having an intake-side fluid chamber and an exhaust-side fluid chamber, supplying pressurized fluid to the intake-side fluid chamber to extend each bellows to a predetermined extended state, and supplying pressurized fluid to the exhaust-side fluid chamber to contract each bellows to a predetermined contracted state; and a control unit that drives the pair of drive units in such a way that one bellows contracts from the extended state just before it is about to enter the contracted state, wherein the bellows pump device comprises The system includes: a pair of detection units that detect the extension and contraction states of each bellows; and a pair of fluid pressure adjustment units that adjust the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of each drive unit. The control unit determines whether the other bellows is in the extension state when one bellows contracts to a state just before it reaches the contraction state, or when one bellows contracts to the contraction state, based on the detection signals from the pair of detection units. If the determination result is negative, the control unit performs current pressure boosting control on the fluid pressure adjustment unit corresponding to the drive unit that extends the other bellows, in a manner that gradually increases the fluid pressure associated with the currently extended other bellows.

[0013] Regarding the bellows pump device of the present invention, when one bellows is contracted to the mid-contraction state, or when one bellows is contracted to the contracted state, sometimes the other bellows does not extend to the predetermined extension state. This is because the other bellows stiffens, causing its extension time to increase. In this case, regarding the other bellows that is currently extended, the control unit performs current pressure boosting control to gradually increase the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of the corresponding drive unit. Therefore, when the extension time of the other bellows increases, it can be automatically reset in such a way that the fluid pressure of the pressurized fluid used to extend the other bellows becomes a gradually increasing value. As a result, the extension time of the other bellows at the current moment is shortened, thus suppressing the worsening of pulsation on the discharge side of the bellows pump device due to its extended extension time.

[0014] (3) According to other viewpoints, the present invention is a bellows pump device comprising: a pair of bellows, which are independently extendable and retractable, drawing in transfer fluid into the interior by extending and discharging transfer fluid from the interior by contracting; a pair of drive units, each having an intake-side fluid chamber and an exhaust-side fluid chamber, supplying pressurized fluid to the intake-side fluid chamber to extend each bellows to a predetermined extended state, and supplying pressurized fluid to the exhaust-side fluid chamber to contract each bellows to a predetermined contracted state; and a control unit that drives the pair of drive units in such a way that one bellows contracts from the extended state just before it is about to enter the contracted state, wherein the bellows... The bellows pump device includes: a pair of detection units that detect the expansion and contraction states of each bellows; and a pair of fluid pressure adjustment units that adjust the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of each drive unit. The control unit, based on the detection signals of each of the pair of detection units, determines whether the other bellows has caused the extension state to last for a time greater than or equal to a predetermined time when one bellows contracts to a state just before it becomes the contracted state. If the determination result is positive, the control unit performs pressure reduction control on the fluid pressure adjustment unit corresponding to the drive unit that causes the other bellows to extend, in a manner that reduces the fluid pressure during the next extension of the other bellows.

[0015] Regarding the bellows pump device of the present invention, when one bellows contracts to its mid-contraction state, sometimes the other bellows maintains a predetermined extension state for a time greater than or equal to a predetermined time. This is because the other bellows softens, causing its extension time to shorten to a time greater than or equal to the desired time. In this case, the control unit performs pressure reduction control during the next extension of the other bellows, lowering the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of the corresponding drive unit. Thus, when the extension time of the other bellows shortens to a time greater than or equal to the desired time, the fluid pressure of the pressurized fluid used to extend the other bellows can be automatically reset to a lower value. As a result, the extension time of the other bellows is extended and the extension rate is reduced, thereby suppressing the generation of impact pressure and cavitation.

[0016] (4) Preferably, the control unit of (1) determines, based on the detection signals of each of the pair of detection units, whether the other bellows has caused the elongation state to last for a time greater than or equal to a predetermined time when the one bellows contracts to the mid-contraction state. If the determination result is positive, the control unit controls the pressure reduction of the fluid pressure adjustment unit corresponding to the drive unit that causes the other bellows to elongate in a manner that reduces the fluid pressure when the other bellows elongates next time.

[0017] In this case, both pressure boosting and pressure depressurization control are performed again. Thus, when the elongation time of the other bellows is extended, the fluid pressure of the pressurizing fluid used to extend the other bellows can be automatically reset to a higher value, and when the elongation time of the other bellows is shortened to a time greater than or equal to the required time, the fluid pressure of the pressurizing fluid used to extend the other bellows can be automatically reset to a lower value.

[0018] (5) Preferably, the control unit determines whether the other bellows is in the extended state when the one bellows is contracted to the contracted state based on the detection signals of the pair of detection units. If the determination result is negative, the lower limit of the adjustment range of the fluid pressure based on the fluid pressure adjustment unit for the next extension of the other bellows is set to be higher than the fluid pressure for the previous extension of the other bellows.

[0019] When the control unit performs pressure reduction control, sometimes when one bellows contracts to the specified contraction state, the other bellows fails to extend to the specified extension state. This is because the pressure reduction control causes an excessive decrease in the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of the corresponding drive unit, resulting in an excessively long extension time for the other bellows. In this case, the control unit sets the lower limit of the fluid pressure adjustment range for the next extension of the other bellows to be higher than the fluid pressure during the previous extension of the other bellows. This prevents the fluid pressure adjusted by the fluid pressure adjustment unit from falling below the lower limit during the next extension of the other bellows, thus suppressing the excessive extension time of the other bellows. Consequently, it suppresses the worsening of pulsation on the discharge side of the bellows pump unit caused by the prolonged extension time.

[0020] (6) Preferably, the control unit determines whether the other bellows is in the extended state when the one bellows is contracted to the contracted state based on the detection signals of the pair of detection units. If the determination result is negative, the lower limit of the adjustment range of the fluid pressure based on the fluid pressure adjustment unit for the extended state of the other bellows after the next time is set to be higher than the fluid pressure when the other bellows was extended in the previous time.

[0021] When the control unit performs pressure reduction control, sometimes when one bellows contracts to the specified contraction state, the other bellows fails to extend to the specified extension state. This is because the pressure reduction control causes an excessive decrease in the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of the corresponding drive unit, resulting in an excessively long extension time for the other bellows. In this case, the control unit can set the lower limit of the fluid pressure adjustment range for the extension of the other bellows after the next major cycle to be higher than the fluid pressure at the previous extension time of the other bellows. This prevents the fluid pressure adjusted by the fluid pressure adjustment unit from falling below the lower limit during the extension of the other bellows after the next major cycle, thus suppressing the excessive extension time of the other bellows. Consequently, it suppresses the worsening of pulsation on the discharge side of the bellows pump unit caused by the prolonged extension time.

[0022] (7) Preferably, the control unit determines whether the other bellows is in the elongated state when the one bellows contracts to the mid-contraction state before it is about to become the contracted state, or when the one bellows contracts to the contracted state, based on the detection signals of the pair of detection units. If the determination result is negative, the control unit controls the current pressure adjustment unit corresponding to the drive unit that causes the other bellows to elongate to control the fluid pressure adjustment unit in a manner that gradually increases the fluid pressure associated with the other bellows that is elongated at the current moment.

[0023] When the control unit performs pressure reduction control, sometimes when one bellows contracts to a predetermined contraction state, the other bellows fails to extend to the predetermined extension state. This is because the pressure reduction control causes an excessive decrease in the pressure of the pressurized fluid supplied to the suction-side fluid chamber of the corresponding drive unit, resulting in an excessively long extension time for the other bellows. In this case, the control unit performs current pressure boosting control, gradually increasing the fluid pressure associated with the other bellows that is currently extending. This shortens the current extension time of the other bellows. Consequently, it suppresses the worsening of pulsation on the discharge side of the bellows pump device caused by the extended extension time. Furthermore, it suppresses incomplete suction of the transferred fluid caused by the extension of the other bellows, thus preventing the bellows pump device from stopping due to this incomplete suction.

[0024] (8) Preferably, the control unit performs the drive control based on each detection signal of a pair of detection units.

[0025] In this case, the pair of detection units used for drive control of a pair of drive units also serve as a pair of detection units used for current boost control, next boost control, or depressurization control, thus simplifying the structure of the bellows pump device.

[0026] The effects of the invention

[0027] According to the bellows pump device of the present invention, when the elongation time of the bellows changes, the fluid pressure of the pressurizing fluid used to elongate the bellows can be automatically reset. Attached Figure Description

[0028] Figure 1 This is a schematic structural diagram of the bellows pump device according to an embodiment of the present invention.

[0029] Figure 2 This is a cross-sectional view of a bellows pump.

[0030] Figure 3 This is an explanatory diagram showing the operation of a bellows pump.

[0031] Figure 4 This is an explanatory diagram showing the operation of a bellows pump.

[0032] Figure 5 This is a timing diagram representing an example of the next boost control.

[0033] Figure 6 This is a timing diagram illustrating an example of buck control.

[0034] Figure 7 This is a timing diagram illustrating an example of resetting the lower limit of the air pressure adjustment range based on an electric pressure regulating valve.

[0035] Figure 8 This is a timing diagram representing Example 1 of the current boost control.

[0036] Figure 9 This is a timing diagram representing Example 2 of the current boost control. Detailed Implementation

[0037] Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0038] [Overall Structure]

[0039] Figure 1This is a schematic structural diagram of a bellows pump device according to an embodiment of the present invention. The bellows pump device 1 of this embodiment is used, for example, in a semiconductor manufacturing apparatus for supplying a constant quantity of transfer fluids such as pharmaceutical solutions and solvents. The bellows pump device 1 includes an air supply device (fluid supply device) 2, a mechanical regulator 3, a first solenoid valve 4, a second solenoid valve 5, a control unit 6, a bellows pump 10, a first electric pressure regulating valve (fluid pressure adjustment unit) 51, and a second electric pressure regulating valve (fluid pressure adjustment unit) 52.

[0040] The air supply device 2, for example, is an air compressor that generates pressurized air (pressurized fluid) to be supplied to the bellows pump 10. A mechanical regulator 3 adjusts the air pressure (fluid pressure) of the pressurized air generated in the air supply device 2. The first electric pressure regulating valve 51 and the second electric pressure regulating valve 52 will be described later.

[0041] Figure 2 This is a cross-sectional view of the bellows pump 10 according to this embodiment. The bellows pump 10 of this embodiment includes: a pump head 11 disposed in the center; a pair of pump housings 12 installed on both sides of the pump head 11 in the left-right direction; a first bellows 13 and a second bellows 14, which are installed inside the pump housings 12 on the sides of the pump head 11 in the left-right direction; and a total of four check valves 15 and 16, which are installed inside the first and second bellows 13 and 14 on the sides of the pump head 11 in the left-right direction.

[0042] [Corrugated pipe]

[0043] The first bellows 13 and the second bellows 14 are formed into a bottomed cylindrical shape from fluoropolymers such as polytetrafluoroethylene (PTFE) and tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer (PFA). The flanges 13a and 14a integrally formed at the open ends of the first and second bellows 13 and 14 are 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 each formed in a serpentine shape, independently configured to extend and retract freely in the left-right direction.

[0044] The working plate 19 is fixed to the outer surface of the closed end of the first and second bellows 13 and 14 using bolts 17 and nuts 18. The first and second bellows 13 and 14 can extend and retract between the maximum elongated state where the outer surface of the working plate 19 abuts against the inner surface of the bottom wall portion 121 of the bottom cylindrical pump housing 12, and the maximum contracted state where the inner surface of the piston body 23 abuts against the outer surface of the bottom wall portion 121 (described later).

[0045] [Pump casing]

[0046] The periphery of the opening of the pump housing 12 (hereinafter also referred to as "first pump housing 12A") is pressed and fixed to the flange portion 13a of the first bellows 13 in an airtight manner. As a result, the first discharge side air chamber (discharge side fluid chamber) 21A, which is kept in an airtight state, is formed on the outside of the first bellows 13 inside the first pump housing 12A.

[0047] A first air intake and exhaust port 22A is provided in the first pump housing 12A. The first air intake and exhaust port 22A is connected to the air supply device 2 via a first solenoid valve 4, a first electric pressure regulating valve 51, and a mechanical regulator 3 (see reference). Figure 1 Therefore, 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 contraction state (hereinafter referred to as the "contraction state"). The contraction state of the first bellows 13 can be the maximum contraction state or a state immediately preceding the maximum contraction state.

[0048] The periphery of the opening of the pump housing 12 (hereinafter also referred to as "the second pump housing 12B") is pressed and fixed to the flange portion 14a of the second bellows 14 in an airtight manner. As a result, the second discharge side air chamber (discharge side fluid chamber) 21B, which is kept in an airtight state, is formed on the outside of the second bellows 14 inside the second pump housing 12B.

[0049] The second pump housing 12B is provided with a second air intake and exhaust port 22B, which is connected to the air supply device 2 via a second solenoid valve 5, a second electric pressure regulating valve 52, and a mechanical regulator 3 (see reference). Figure 1 Therefore, if pressurized air is supplied from the air supply device 2 to the interior of the second exhaust side air chamber 21B, the second bellows 14 contracts to a predetermined contraction state (hereinafter referred to as the "contraction state"). The contraction state of the second bellows 14 can be the maximum contraction state or a state immediately preceding the maximum contraction state.

[0050] A rod-shaped connecting member 20 passes through the bottom wall portion 121 of each pump housing 12A, 12B, and the connecting member 20 is supported on the bottom wall portion 121 in a manner that allows it to slide in the left and 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 integrally provided on the outer side of the bottom wall portion 121 in a manner that allows it to slide in the left and right direction while maintaining an airtight state.

[0051] Therefore, on the first pump housing 12A side, the space surrounded by the bottom wall portion 121, the cylinder body 25, and the piston body 23 is configured as a first intake-side air chamber (intake-side fluid chamber) 26A that is kept airtight. Similarly, on the second pump housing 12B side, the space surrounded by the bottom wall portion 121, the cylinder body 25, and the piston body 23 is configured as a second intake-side air chamber (intake-side fluid chamber) 26B that is kept airtight.

[0052] An intake and exhaust port 251 communicating with the first intake-side air chamber 26A is formed on the cylinder 25 on the first pump housing 12A side. This intake and exhaust port 251 is connected to the air supply device 2 via a first solenoid valve 4, a first electric pressure regulating valve 51, and a mechanical regulator 3 (see reference). Figure 1 Therefore, if pressurized air is supplied from the air supply device 2 to the interior of the first intake-side air chamber 26A via the intake and exhaust ports 251, the first bellows 13 extends to a predetermined extension state (hereinafter referred to as the "extension state"). The extension state of the first bellows 13 can be the maximum extension state or the state immediately preceding the maximum extension state.

[0053] An intake and exhaust port 252 communicating with the second intake-side air chamber 26B is formed on the cylinder 25 on the second pump housing 12B side. This intake and exhaust port 252 is connected to the air supply device 2 via a second solenoid valve 5, a second electric pressure regulating valve 52, and a mechanical regulator 3 (see reference). Figure 1 Therefore, if pressurized air is supplied from the air supply device 2 to the interior of the second intake-side air chamber 26B via the intake and exhaust ports 252, the second bellows 14 extends to a predetermined extension state (hereinafter referred to as the "extension state"). The extension state of the second bellows 14 can be the maximum extension state or a state immediately preceding the maximum extension state.

[0054] Based on the above structure, the first pump housing 12A formed inside the first discharge side air chamber 21A, the piston body 23 and the cylinder body 25 forming the first intake side air chamber 26A constitute a first drive unit (drive unit) 27 that enables the first bellows 13 to continuously extend and retract between the extended state and the contracted state.

[0055] In addition, the second pump housing 12B formed inside the second discharge side air chamber 21B, the piston body 23 forming the second intake side air chamber 26B, and the cylinder body 25 constitute a second drive unit (drive unit) 28 that enables the second bellows 14 to continuously extend and retract between the extended and retracted states.

[0056] [Testing Department]

[0057] A pair of proximity sensors 29A and 29B are mounted on the cylinder 25 of the first drive unit 27. A detection plate 30, which is detected by each proximity sensor 29A and 29B, is mounted on the piston 23 of the first drive unit 27. The detection plate 30 moves back and forth with the piston 23 and alternately approaches the proximity sensors 29A and 29B.

[0058] Proximity sensor 29A is positioned to detect the plate 30 during the mid-contraction phase of the first bellows 13, just before it enters the contracted state. Proximity sensor 29B is positioned to detect the plate 30 when the first bellows 13 is in the extended state. If either proximity sensor 29A or 29B detects the plate 30, it outputs its detection signal to the control unit 6. The pair of proximity sensors 29A and 29B function as a first detection unit (detection unit) for detecting the extension and retraction state of the first bellows 13.

[0059] A pair of proximity sensors 31A and 31B are mounted on the cylinder 25 of the second drive unit 28. A detection plate 32, which is detected by each proximity sensor 31A and 31B, is mounted on the piston 23 of the second drive unit 28. The detection plate 32 moves back and forth with the piston 23, alternately approaching the proximity sensors 31A and 31B.

[0060] Proximity sensor 31A is positioned to detect the plate 32 during the mid-contraction phase of the second bellows 14, just before it retracts. Proximity sensor 31B is positioned to detect the plate 32 when the second bellows 14 is extended. If either proximity sensor 31A or 31B detects the plate 32, it outputs its detection signal to the control unit 6. The pair of proximity sensors 31A and 31B function as a second detection unit (detection unit) for detecting the extension and retraction state of the second bellows 14.

[0061] Here, the "mid-contraction state" of the first bellows 13 (second bellows 14) refers to the position where the first bellows 13 (second bellows 14) has passed through a contraction state that is closer to the end of the contraction state (contraction state) than the position where the contraction begins (elongation state). More specifically, it refers to the position where the first bellows 13 (second bellows 14) is at 50% to 90% of the contraction length from the contraction state to the elongation state.

[0062] [Pump head]

[0063] The pump head 11 is formed of fluoropolymers such as PTFE and PFA. Inside the pump head 11, there is a suction passage 34 and a discharge passage 35 for transferring fluid. The suction passage 34 and the discharge passage 35 open on the outer peripheral surface of the pump head 11 and are connected to the suction port and discharge port (both not shown) provided on the outer peripheral surface.

[0064] The suction port is connected to a storage tank for the transferred fluid, and the discharge port is connected to the destination of the transferred fluid. Furthermore, the suction passage 34 and the discharge passage 35 branch out toward the left and right sides of the pump head 11, respectively, and each has a suction port 36 and a discharge port 37 opening on the left and right sides of the pump head 11. Each suction port 36 and each discharge port 37 communicates with the interior of the bellows 13 and 14 via check valves 15 and 16, respectively.

[0065] [Check valve]

[0066] One-way valves 15 and 16 are installed at each inlet 36 and each outlet 37.

[0067] The one-way valve 15 (hereinafter also referred to as "one-way valve for inhalation") installed at the inlet 36 has: a valve housing 15a; a valve body 15b housed in the valve housing 15a; and a compression coil spring 15c that preloads the valve body 15b in the valve closing direction.

[0068] The valve housing 15a is formed into a bottomed cylindrical shape. A through hole 15d communicating with the interior of the bellows 13 and 14 is formed on the bottom wall of the valve housing 15a. The valve body 15b closes the suction port 36 (closes the valve) by the preload of the compression helical spring 15c. If a back pressure is applied based on the flow of the conveyed fluid accompanying the expansion and contraction of the bellows 13 and 14, the suction port 36 will open (open).

[0069] Therefore, the suction check valve 15 opens when its bellows 13 and 14 extend, allowing the suction of fluid moving from the suction passage 34 toward the interior of the bellows 13 and 14 (one direction). Conversely, the suction check valve 15 closes when its bellows 13 and 14 contract, preventing backflow of fluid moving from the interior of the bellows 13 and 14 toward the suction passage 34 (the other direction).

[0070] The one-way valve 16 (hereinafter also referred to as "discharge one-way valve") installed at the outlet 37 has: a valve housing 16a; a valve body 16b housed in the valve housing 16a; and a compression coil spring 16c that preloads the valve body 16b in the valve closing direction.

[0071] The valve housing 16a is formed into a bottomed cylindrical shape. A through hole 16d communicating with the interior of the bellows 13 and 14 is formed on the bottom wall of the valve housing 16a. The valve body 16b closes the through hole 16d of the valve housing 16a (closes the valve) by the preload of the compression coil spring 16c. If a back pressure is applied based on the flow of the conveyed fluid accompanying the expansion and contraction of the bellows 13 and 14, the through hole 16d of the valve housing 16a is opened (opens the valve).

[0072] Therefore, the discharge check valve 16 opens when its bellows 13 and 14 contract, allowing the fluid transferred from inside the bellows 13 and 14 toward the discharge passage 35 (one direction). Conversely, the discharge check valve 16 closes when its bellows 13 and 14 extend, preventing backflow of the fluid transferred from the discharge passage 35 toward the bellows 13 and 14 (the other direction).

[0073] [Operation of the bellows pump]

[0074] Next, refer to Figure 3 and Figure 4 The operation of the bellows pump 10 according to this embodiment will be explained. Furthermore, in Figure 3 and Figure 4 The simplified diagram shows the structure of the first and second bellows 13 and 14. (See diagram for reference.) Figure 3 As 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, which are mounted on the left side of the pump head 11 in the figure, are pressurized by the fluid transferred from the first bellows 13 and move to the right side of the respective valve bodies 15a and 16a in the figure. As a result, the suction check valve 15 closes and the discharge check valve 16 opens, allowing the fluid transferred from the first bellows 13 to be discharged out of the pump through the discharge passage 35.

[0075] 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 due to 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 due to 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, drawing transfer fluid from the suction passage 34 into the second bellows 14.

[0076] Next, as Figure 4 As shown, with the first bellows 13 extended and the second bellows 14 contracted, the valve bodies 15b and 16b of the suction check valve 15 and discharge check valve 16, which are mounted on the right side of the pump head 11 in the figure, are pressurized by the fluid transferred within the second bellows 14 and move to the left side of the valve bodies 15a and 16a in the figure. Consequently, the suction check valve 15 closes and the discharge check valve 16 opens, allowing the fluid transferred within the second bellows 14 to be discharged out of the pump through the discharge passage 35.

[0077] On the other hand, the valve body 15b of the suction check valve 15, which is 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 due to the suction action of the first bellows 13. The valve body 16b of the discharge check valve 16, which is 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 due to the suction action of the first bellows 13 and the pressing action based on 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 drawn into the first bellows 13 from the suction passage 34.

[0078] By repeatedly performing the above actions, the left and right bellows 13 and 14 can alternately draw in and discharge the fluid.

[0079] [Solenoid valve]

[0080] exist Figure 1 In this configuration, the first solenoid valve 4 is, for example, a three-way (three-position) solenoid switching valve having a pair of solenoids 4a and 4b. Each solenoid 4a and 4b is energized based on a command signal received from the control unit 6. Thus, the first solenoid valve 4 is switched by the control unit 6. The first solenoid valve 4 switches between 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 intake-side air chamber 26A in the first drive unit 27.

[0081] Specifically, if the solenoid 4a of the first solenoid valve 4 is energized, it switches to a state where pressurized air is supplied to the first discharge-side air chamber 21A and pressurized air in the first intake-side air chamber 26A is discharged. Conversely, if the solenoid 4b of the first solenoid valve 4 is energized, it switches to a state where pressurized air in the first discharge-side air chamber 21A is discharged and pressurized air is supplied to the first intake-side air chamber 26A.

[0082] The second solenoid valve 5 is, for example, a three-way solenoid switching valve having a pair of solenoids 5a and 5b. Each solenoid 5a and 5b is energized by receiving a command signal from the control unit 6. Thus, the second solenoid valve 5 is switched by the control unit 6. The second solenoid valve 5 switches between the supply and discharge of pressurized air to the second exhaust air chamber 21B and the supply and discharge of pressurized air to the second intake air chamber 26B in the second drive unit 28.

[0083] Specifically, if the solenoid 5a of the second solenoid valve 5 is energized, it switches to a state where pressurized air is supplied to the second discharge-side air chamber 21B and pressurized air in the second intake-side air chamber 26B is discharged. Conversely, if the solenoid 5b of the second solenoid valve 5 is energized, it switches to a state where pressurized air in the second discharge-side air chamber 21B is discharged and pressurized air is supplied to the second intake-side air chamber 26B.

[0084] Furthermore, in this embodiment, the first and second solenoid valves 4 and 5 are composed of three-way solenoid switching valves, or they can be two-position solenoid switching valves without a neutral position.

[0085] [Electrical pressure regulating valve]

[0086] The first electric pressure regulating valve 51 is disposed between the mechanical regulator 3 and the first solenoid valve 4. The first electric pressure regulating valve 51 adjusts the air pressure of the pressurized air supplied to the first intake air chamber 26A of the first drive unit 27 and the air pressure of the pressurized air supplied to the first discharge air chamber 21A of the first drive unit 27.

[0087] The second electric pressure regulating valve 52 is disposed between the mechanical regulator 3 and the second solenoid valve 5. The second electric pressure regulating valve 52 adjusts the air pressure of the pressurized air supplied to the second intake air chamber 26B of the second drive unit 28 and the air pressure of the pressurized air supplied to the second discharge air chamber 21B of the second drive unit 28, respectively.

[0088] Furthermore, the electric pressure regulating valves 51 and 52 only need to adjust the air pressure of the pressurized air supplied to the intake air chambers 26A and 26B. In this embodiment, the electric pressure regulating valves 51 and 52, which directly adjust the air pressure, are used as fluid pressure regulating units. However, the air pressure can be indirectly adjusted using an air flow regulating valve that adjusts the air flow rate. Alternatively, devices that adjust the pressure or flow rate of gases other than air (e.g., nitrogen), liquids, etc., can be used.

[0089] [Control Department]

[0090] exist Figure 1 and Figure 2 In this configuration, the control unit 6 is configured as a computer equipped with a CPU or the like. The CPU executes the control program stored in the computer's storage device to perform the various functions of the control unit 6. Based on the detection results of the first detection unit 29 and the second detection unit 31, the control unit 6 switches the first solenoid valve 4 and the second solenoid valve 5 to drive the first drive unit 27 and the second drive unit 28.

[0091] Specifically, based on the detection results of the first detection unit 29 and the second detection unit 31, the control unit 6 controls each drive of the first drive unit 27 and the second drive unit 28 in the following manner: before the first bellows 13 is about to become a contracted state, the second bellows 14 is contracted from an extended state, and before the second bellows 14 is about to become a contracted state, the first bellows 13 is contracted from an extended state.

[0092] The control unit 6 performs drive control in the manner described above. When one of the first bellows 13 and the second bellows 14 switches from contraction to extension (transfer fluid from discharge to intake), the other bellows has already contracted and discharged the transfer fluid. Therefore, the phenomenon of a significant drop in the discharge pressure of the transfer fluid at the specified timing can be reduced. As a result, the pulsation on the discharge side of the bellows pump 10 can be weakened.

[0093] In the drive control, for example, if the ambient temperature decreases, the first bellows 13 and the second bellows 14 become stiff due to the effect, and sometimes the elongation time of each of the first bellows 13 and the second bellows 14 is prolonged. In this case, the control unit 6 performs the next boost control to shorten the elongation time of each of the first bellows 13 and the second bellows 14, as well as the current boost control.

[0094] Specifically, based on the detection results of the first detection unit 29 and the second detection unit 31, the control unit 6 makes a first determination as to whether the second bellows 14 (first bellows 13) is in an extended state when the first bellows 13 (second bellows 14) is in a state of contraction. If the result of the first determination is negative (not in an extended state), when the second bellows 14 (first bellows 13) extends again, the control unit 6 controls the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) to increase the air pressure of the pressurized air supplied to the second intake air chamber 26B (first intake air chamber 26A). Preferably, the increase in air pressure for the next pressure increase control is set to +1 kPa to +50 kPa (more preferably +1 kPa to +20 kPa).

[0095] If the determination result of the first determination as described above is negative (not in an elongated state), regarding the currently elongated second bellows 14 (first bellows 13), the control unit 6 further controls the current pressure increase control of the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) in a manner that gradually increases the air pressure of the pressurized air supplied to the second intake side air chamber 26B (first intake side air chamber 26A). Preferably, the degree of increase of the air pressure under current pressure increase control is set to +1 kPa to +100 kPa (more preferably +1 kPa to +30 kPa) every 1 msec to 100 msec (more preferably every 1 msec to 30 msec).

[0096] On the other hand, in the drive control, for example, if the ambient temperature rises, the first bellows 13 and the second bellows 14 soften due to the effect, and sometimes the elongation time of each of the first bellows 13 and the second bellows 14 is shortened. In this case, the control unit 6 performs pressure reduction control to extend the elongation time of each of the first bellows 13 and the second bellows 14.

[0097] Specifically, based on the detection results of the first detection unit 29 and the second detection unit 31, the control unit 6 performs a second determination on whether the elongation state of the second bellows 14 (first bellows 13) continues for a period of time greater than or equal to a predetermined time when the first bellows 13 (second bellows 14) has contracted to the mid-contraction state. Preferably, the predetermined time is set to a value of 500 msec (preferably 10 to 200 msec).

[0098] If the result of the second determination is affirmative (the elongation state continues for a period of time greater than or equal to a predetermined time), during the next elongation of the second bellows 14 (first bellows 13), the control unit 6 controls the pressure reduction of the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) in a manner that reduces the air pressure of the pressurized air supplied to the second intake air chamber 26B (first intake air chamber 26A). Preferably, the pressure reduction degree of the air pressure is set to -1 kPa to -50 kPa (more preferably -1 kPa to -20 kPa).

[0099] When pressure reduction control is applied, it is considered that the air pressure of the pressurized air supplied to the second intake air chamber 26B (first intake air chamber 26A) may be excessively reduced. In this case, the extension time of the second bellows 14 (first bellows 13) becomes too long, and even if the first bellows 13 (second bellows 14) contracts to the contracted state, the second bellows 14 (first bellows 13) may not reach the extended state. As a result, the drive control cannot be performed normally, and the pulsation on the discharge side of the bellows pump 10 worsens. Therefore, when the air pressure of the pressurized air supplied to the second intake air chamber 26B (first intake air chamber 26A) is excessively reduced due to pressure reduction control, the control unit 6 resets the lower limit of the adjustment range based on the air pressure of the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) during the next extension of the second bellows 14 (first bellows 13).

[0100] Specifically, based on the detection results of the first detection unit 29 and the second detection unit 31, the control unit 6 performs a third determination to determine whether the second bellows 14 (first bellows 13) is in an extended state when the first bellows 13 (second bellows 14) is contracted to the contracted state. If the result of the third determination is negative (not in an extended state), the control unit 6 sets the lower limit of the adjustment range of the air pressure based on the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) to be higher than the air pressure when the second bellows 14 (first bellows 13) was extended in the previous instance.

[0101] The lower limit of the air pressure adjustment range is preferably set to +1 kPa to +50 kPa (more preferably +5 kPa to +20 kPa). Furthermore, the upper limit of the air pressure adjustment range is fixed and will not change even if the lower limit is reset. This reset lower limit is used as the lower limit of the air pressure adjustment range for the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) even when the second bellows 14 (first bellows 13) extends after the next major cycle.

[0102] If the air pressure of the pressurized air supplied to the second intake air chamber 26B (first intake air chamber 26A) is excessively reduced due to the pressure reduction control, the control unit 6 further performs the aforementioned current pressure boosting control. Specifically, if the result of the third determination is negative (not in an extended state), regarding the currently extended second bellows 14 (first bellows 13), the control unit 6 further performs current pressure boosting control of the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) in a manner that gradually increases the air pressure of the pressurized air supplied to the second intake air chamber 26B (first intake air chamber 26A).

[0103] [Specific example of the next boost control]

[0104] Figure 5 This is a timing diagram illustrating an example of the next boost control performed in the drive control using control unit 6. Below, refer to... Figure 1 and Figure 5 The drive control and the next pressurization control performed by the control unit 6 will be explained. Here, the explanation will be given from the state where the first bellows 13 is in the contraction action (exhausting) and the second bellows 14 is in the extension action (inhaling).

[0105] At time t1, when proximity sensor 29A detects the first bellows 13 in a mid-contraction state (ON), control unit 6 determines whether proximity sensor 31B has detected the second bellows 14 in an extension state (ON) (first determination). Here, at time t1, proximity sensor 31B does not detect the second bellows 14 in an extension state (OFF), therefore control unit 6 determines that proximity sensor 31B has not turned ON. Based on this determination result, as described later, control unit 6 executes the next boost control at the next extension of the second bellows 14 (times t6 to t7).

[0106] If the control unit 6 determines that the proximity sensor 31B is not ON, it waits until the proximity sensor 31B becomes ON. Furthermore, at time t2 when the proximity sensor 31B becomes ON, the control unit 6 demagnetizes the solenoid 5b of the second solenoid valve 5 and energizes the solenoid 5a. Additionally, if the control unit 6 determines that the proximity sensor 31B becomes ON at time t1, it immediately demagnetizes the solenoid 5b of the second solenoid valve 5 and energizes the solenoid 5a.

[0107] If the solenoid 5a of the second solenoid valve 5 is energized, the pressurized air generated in the air supply device 2 is supplied to the second discharge side air chamber 21B of the second drive unit 28 via the mechanical regulator 3, the second electric pressure regulating valve 52, and the second solenoid valve 5. At this time, the control unit 6 controls the second electric pressure regulating valve 52 so that the air pressure of the pressurized air supplied to the second discharge side air chamber 21B becomes a predetermined value P2. As a result, the second bellows 14 begins to contract from the extended state just before the first bellows 13 is about to enter the contracted state.

[0108] After the second bellows 14 begins to contract, the control unit 6 determines that the first bellows 13 has entered the contracted state at time t3, after a predetermined calculation time has elapsed from the moment t1 when the proximity sensor 29A turns ON. Furthermore, the control unit 6 demagnetizes the solenoid 4a of the first solenoid valve 4 and energizes the solenoid 4b.

[0109] If the solenoid 4b of the first solenoid valve 4 is energized, the pressurized air generated in the air supply device 2 is supplied to the first intake air chamber 26A of the first drive unit 27 via the mechanical regulator 3, the first electric pressure regulating valve 51, and the first solenoid valve 4. At this time, the control unit 6 controls the first electric pressure regulating valve 51 so that the air pressure of the pressurized air supplied to the first intake air chamber 26A becomes a predetermined value P11. As a result, the first bellows 13 begins to extend from the contracted state.

[0110] Next, at time t4, when proximity sensor 31A detects the (ON) mid-contraction state of the second bellows 14, control unit 6 determines whether proximity sensor 29B has detected the (ON) extension state of the first bellows 13 (first determination). Here, at time t4, proximity sensor 29B does not detect the (OFF) extension state of the first bellows 13, therefore control unit 6 determines that proximity sensor 29B has not turned ON. Based on this determination result, as described later, control unit 6 executes the next boost control at the next extension of the first bellows 13 (times t8 to t9).

[0111] If the control unit 6 determines that the proximity sensor 29B has not turned ON, the proximity sensor 29B waits until it turns ON. Furthermore, at time t5 when the proximity sensor 29B turns ON, the control unit 6 demagnetizes the solenoid 4b of the first solenoid valve 4 and energizes the solenoid 4a. Additionally, if the control unit 6 determines that the proximity sensor 29B has turned ON at time t4, it immediately demagnetizes the solenoid 4b of the first solenoid valve 4 and energizes the solenoid 4a.

[0112] If the solenoid 4a of the first solenoid valve 4 is energized, the pressurized air generated in the air supply device 2 is supplied to the first discharge side air chamber 21A of the first drive unit 27 via the mechanical regulator 3, the first electric pressure regulating valve 51, and the first solenoid valve 4. At this time, the control unit 6 controls the first electric pressure regulating valve 51 in such a way that the air pressure of the pressurized air supplied to the first discharge side air chamber 21A becomes a predetermined value P1. As a result, the first bellows 13 begins to contract from the extended state just before the second bellows 14 is about to enter the contracted state.

[0113] After the first bellows 13 begins to contract, the control unit 6 determines that the second bellows 14 has entered the contracted state after a predetermined time t6 has elapsed since the proximity sensor 31A turns ON. Furthermore, the control unit 6 demagnetizes the solenoid 5a of the second solenoid valve 5 and energizes the solenoid 5b.

[0114] If the solenoid 5b of the second solenoid valve 5 is energized, the pressurized air generated in the air supply device 2 is supplied to the second intake air chamber 26B of the second drive unit 28 via the mechanical regulator 3, the second electric pressure regulating valve 52, and the second solenoid valve 5. At this time, the first determination performed by the control unit 6 at time t1 is negative (determined that the proximity sensor 31B has not turned ON), and therefore, the control unit 6 performs the next pressure boosting control of the second electric pressure regulating valve 52 in a manner that increases the air pressure of the pressurized air supplied to the second intake air chamber 26B.

[0115] Specifically, the control unit 6 controls the second electric pressure regulating valve 52 in a manner that makes the air pressure of the pressurized air supplied to the second intake side air chamber 26B higher than the previous value P21 (before time t2) P22. As a result, the second bellows 14 begins to extend from the contracted state. This extension speed is faster than the previous extension speed of the second bellows 14.

[0116] Next, at time t7 when proximity sensor 29A detects that the first bellows 13 is in a contracted state (ON), control unit 6 determines whether proximity sensor 31B has detected that the second bellows 14 is in an extended state (first determination). Here, as described above, the extension speed of the second bellows 14 increases, and the extension time of the second bellows 14 shortens, so the second bellows 14 reaches an extended state at time t7. Therefore, proximity sensor 31B detects the extended state of the second bellows 14 at time t7, and control unit 6 determines that proximity sensor 31B is ON. Based on this determination, control unit 6 does not perform the next boost control when the second bellows 14 extends again.

[0117] When the control unit 6 determines that the proximity sensor 31B is ON, it demagnetizes the solenoid 5b of the second solenoid valve 5 and energizes the solenoid 5a. If the solenoid 5a of the second solenoid valve 5 is energized, then as described above, the second bellows 14 begins to contract from the extended state just before the first bellows 13 is about to enter the contracted state (mid-contraction state).

[0118] After the second bellows 14 begins to contract, the control unit 6 determines that the first bellows 13 has entered a contracted state at a predetermined calculation time t8 after the moment t7 when the proximity sensor 29A turns ON. This causes the solenoid 4a of the first solenoid valve 4 to demagnetize and the solenoid 4b to be energized. If the solenoid 4b of the first solenoid valve 4 is energized, then, as described above, the pressurized air generated in the air supply device 2 is supplied to the first intake-side air chamber 26A of the first drive unit 27.

[0119] At this time, the first determination made by the control unit 6 at time t4 is negative (it is determined that the proximity sensor 29B has not turned ON), so the next pressure boosting control of the first electric pressure regulating valve 51 is executed in such a way as to increase the air pressure of the pressurized air supplied to the first intake side air chamber 26A.

[0120] Specifically, the control unit 6 controls the first electric pressure regulating valve 51 to make the air pressure of the pressurized air supplied to the first intake side air chamber 26A higher than the previous value P11 (time t3 to time t5) P12. As a result, the first bellows 13 begins to extend from the contracted state. This extension speed is faster than the extension speed of the first bellows 13 during the previous extension operation.

[0121] Next, at time t9 when proximity sensor 31A detects that the second bellows 14 is in a mid-contraction state (ON), control unit 6 determines whether proximity sensor 29B has detected that the first bellows 13 is in an extended state (first determination). Here, as described above, the extension speed of the first bellows 13 increases, and the extension time of the first bellows 13 shortens, so that the first bellows 13 reaches an extended state at time t9. Therefore, at time t9, proximity sensor 29B detects the extended state of the first bellows 13, and control unit 6 determines that proximity sensor 29B is ON. Based on this determination result, control unit 6 does not perform the next boost control when the first bellows 13 extends again.

[0122] When the control unit 6 determines that the proximity sensor 29B is ON, it demagnetizes the solenoid 4b of the first solenoid valve 4 and energizes the solenoid 4a. If the solenoid 4a of the first solenoid valve 4 is energized, then as described above, the first bellows 13 begins to contract from the extended state just before the second bellows 14 is about to enter the contracted state (mid-contraction state).

[0123] [Specific examples of buck control]

[0124] Figure 6 This is a timing diagram illustrating an example of buck control performed by control unit 6 in drive control. Below, refer to... Figure 1 and Figure 6 The step-down control performed by control unit 6 will be explained here. Figure 5 Similarly, the description will be given from the state where the first bellows 13 is in the contraction action (exhausting) and the second bellows 14 is in the extension action (inhaling).

[0125] Before the proximity sensor 29A detects that the first bellows 13 is in a mid-contraction state (ON), the control unit 6 determines whether the proximity sensor 31B has detected that the second bellows 14 is in an extended state (ON). Here, at time t20 before the first bellows 13 reaches the mid-contraction state, the proximity sensor 31B detects that the second bellows 14 is in an extended state, so the control unit 6 determines that the proximity sensor 31B is ON.

[0126] When the control unit 6 determines that the proximity sensor 31B is ON, it further determines, at the moment t21 when the proximity sensor 29A detects the first bellows 13 in the mid-contraction state, whether the time elapsed since the proximity sensor 31B detected the second bellows 14 in the extension state has been greater than or equal to a predetermined time T (second determination). Here, the predetermined time T has elapsed since moment t21, so the control unit 6 determines that the time elapsed since moment t20 has been greater than or equal to the predetermined time T. Based on this determination result, as will be described later, the control unit 6 performs pressure reduction control during the next extension of the second bellows 14 (moments t25 to t26).

[0127] At the moment t21 when the proximity sensor 29A turns ON, the control unit 6 demagnetizes the solenoid 5b of the second solenoid valve 5 and energizes the solenoid 5a. If the solenoid 5a of the second solenoid valve 5 is energized, then as described above, the second bellows 14 begins to contract from the extended state just before the first bellows 13 is about to enter the contracted state (mid-contraction state).

[0128] After the second bellows 14 begins to contract, the control unit 6 determines that the first bellows 13 has entered the contracted state at time t22, after a predetermined calculation time has elapsed from the moment t21 when the proximity sensor 29A turns ON. Furthermore, the control unit 6 demagnetizes the solenoid 4a of the first solenoid valve 4 and energizes the solenoid 4b. If the solenoid 4b of the first solenoid valve 4 is energized, the first bellows 13 begins to extend from the contracted state, as described above.

[0129] Next, before the proximity sensor 31A detects that the second bellows 14 is in a mid-contraction state (ON), the control unit 6 determines whether the proximity sensor 29B has detected that the first bellows 13 is in an extended state (ON). Here, at time t23 before the second bellows 14 reaches the mid-contraction state, the proximity sensor 29B detects that the first bellows 13 is in an extended state, so the control unit 6 determines that the proximity sensor 29B is ON.

[0130] When the control unit 6 determines that the proximity sensor 29B is ON, it further determines, at the moment t24 when the proximity sensor 31A detects the second bellows 14 in the mid-contraction state, whether the time elapsed since the proximity sensor 29B detected the second bellows 14 in the extension state has been greater than or equal to a predetermined time T (second determination). Here, the predetermined time T has elapsed since moment t24, so the control unit 6 determines that the time elapsed since moment t23 has been greater than or equal to the predetermined time T. Based on this determination result, as described later, the control unit 6 performs voltage reduction control during the next extension of the first bellows 13 (moments t27 to t28).

[0131] At the moment t24 when the proximity sensor 31A turns ON, the control unit 6 demagnetizes the solenoid 4b of the first solenoid valve 4 and energizes the solenoid 4a. If the solenoid 4a of the first solenoid valve 4 is energized, then as described above, just before the second bellows 14 is about to enter the contracted state (mid-contraction state), the first bellows 13 begins to contract from the extended state.

[0132] After the first bellows 13 begins to contract, the control unit 6 determines that the second bellows 14 has entered the contracted state at time t25, after a predetermined calculation time has elapsed from the moment t24 when the proximity sensor 31A turns ON. Furthermore, the control unit 6 demagnetizes the solenoid 5a of the second solenoid valve 5 and energizes the solenoid 5b. If the solenoid 5b of the second solenoid valve 5 is energized, as described above, the pressurized air generated in the air supply device 2 is supplied to the second intake-side air chamber 26B of the second drive unit 28.

[0133] At this time, the control unit 6 determines the result of the second determination at time t21 as positive (it is determined that the time t20 when the proximity sensor 31B becomes ON has lasted for a time greater than or equal to a predetermined time T). Therefore, it performs pressure reduction control on the second electric pressure regulating valve 52 in a manner that reduces the air pressure of the pressurized air supplied to the second intake side air chamber 26B.

[0134] Specifically, the control unit 6 controls the second electric pressure regulating valve 52 such that the air pressure of the pressurized air supplied to the second intake side air chamber 26B becomes a lower value P23 than the previous value P21 (before time t21). As a result, the second bellows 14 begins to extend from its contracted state. Its extension speed is slower than the previous extension speed of the second bellows 14.

[0135] Next, before the proximity sensor 29A detects that the first bellows 13 is in a mid-contraction state, the control unit 6 determines whether the proximity sensor 31B has detected that the second bellows 14 is in an extended state. Here, as described above, the extension speed of the second bellows 14 is slowed down, and the extension time of the second bellows 14 is prolonged, so that at the moment t26 when the first bellows 13 reaches the mid-contraction state, the second bellows 14 reaches the extended state.

[0136] Therefore, before the first bellows 13 reaches the mid-contraction state, the proximity sensor 31B does not detect the extension state of the second bellows 14 (OFF), so the control unit 6 determines that the proximity sensor 31B has not turned ON. Based on this determination, at the moment t26 when the first bellows 13 reaches the mid-contraction state, the second determination based on the control unit 6 is not performed, and therefore, pressure reduction control is not performed during the next extension of the second bellows 14.

[0137] At the moment t26 when the proximity sensor 31B turns ON, the control unit 6 demagnetizes the solenoid 5b of the second solenoid valve 5 and energizes the solenoid 5a. If the solenoid 5a of the second solenoid valve 5 is energized, then as described above, the second bellows 14 begins to contract from the extended state just before the first bellows 13 is about to enter the contracted state (mid-contraction state).

[0138] After the second bellows 14 begins to contract, the control unit 6 determines that the first bellows 13 has entered a contracted state at time t27, after a predetermined calculation time has elapsed from the moment t26 when the proximity sensor 29A turns ON. Furthermore, the control unit 6 demagnetizes the solenoid 4a of the first solenoid valve 4 and energizes the solenoid 4b. If the solenoid 4b of the first solenoid valve 4 is energized, as described above, the pressurized air generated in the air supply device 2 is supplied to the first intake-side air chamber 26A of the first drive unit 27.

[0139] At this time, if the second determination performed by the control unit 6 at time t24 is affirmative (determining whether the time t23 when the proximity sensor 29B becomes ON has lasted for a time greater than or equal to a predetermined time T), the control unit 6 performs pressure reduction control on the first electric pressure regulating valve 51 in such a way that the air pressure of the pressurized air supplied to the first intake side air chamber 26A is reduced.

[0140] Specifically, the control unit 6 controls the first electric pressure regulating valve 51 to make the air pressure of the pressurized air supplied to the first intake side air chamber 26A lower than the previous value P11 (time t22 to time t24) by a value P13. As a result, the first bellows 13 begins to extend from the contracted state. Its extension speed is slower than the extension speed during the previous extension operation of the first bellows 13.

[0141] Next, before the proximity sensor 31A detects that the second bellows 14 is in a mid-contraction state, the control unit 6 determines whether the proximity sensor 29B has detected that the first bellows 13 is in an extended state. Here, as described above, the extension speed of the first bellows 13 slows down, and the extension time of the first bellows 13 is extended, so that at the moment t28 when the second bellows 14 reaches the mid-contraction state, the first bellows 13 reaches the extended state.

[0142] Therefore, before the second bellows 14 reaches the mid-contraction state, the proximity sensor 29B does not detect the extension state of the first bellows 13 (OFF), so the control unit 6 determines that the proximity sensor 29B has not turned ON. Based on this determination, at the moment t28 when the second bellows 14 reaches the mid-contraction state, no second determination based on the control unit 6 is performed, so no pressure reduction control is performed during the next extension of the first bellows 13.

[0143] [Specific examples of resetting the lower limit value]

[0144] Figure 7 This is a timing diagram illustrating an example of resetting the lower limit of the air pressure adjustment range based on the electric pressure regulating valves 51 and 52 after pressure reduction control is performed using the control unit 6. Below, refer to... Figure 1 and Figure 7 The resetting of the lower limit value executed by control unit 6 will be explained. Furthermore, regarding the... Figure 7 Control performed between time t40 and time t44, and from Figure 6 The control measures performed between time t20 and time t24 are roughly the same, so the explanation is omitted.

[0145] At time t45, after a predetermined calculation time has elapsed from the moment t44 when the proximity sensor 31A turns ON, the control unit 6 determines that the second bellows 14 has entered a contracted state. Furthermore, the control unit 6 demagnetizes the solenoid 5a of the second solenoid valve 5 and energizes the solenoid 5b. If the solenoid 5b of the second solenoid valve 5 is energized, as described above, the pressurized air generated in the air supply device 2 is supplied to the second intake-side air chamber 26B of the second drive unit 28.

[0146] At this time, the control unit 6 determines the result of the second determination at time t41 as positive (it is determined that the time t40 when the proximity sensor 31B becomes ON has lasted for a time greater than or equal to the predetermined time T). Therefore, it performs pressure reduction control on the second electric pressure regulating valve 52 in a manner that reduces the air pressure of the pressurized air supplied to the second intake side air chamber 26B.

[0147] Specifically, the control unit 6 controls the second electric pressure regulating valve 52 to make the air pressure of the pressurized air supplied to the second intake side air chamber 26B a lower value P24 than the previous value P21 (before time t41). As a result, the second bellows 14 begins to extend from the contracted state. Its extension speed is slower than the extension speed during the previous extension operation of the second bellows 14.

[0148] Next, before the proximity sensor 29A detects that the first bellows 13 is in a mid-contraction state, the control unit 6 determines whether the proximity sensor 31B has detected that the second bellows 14 is in an extension state. Here, as described above, the extension speed of the second bellows 14 is slowed down, and the extension time of the second bellows 14 is prolonged, so that at the moment t46 when the first bellows 13 reaches the mid-contraction state, the second bellows 14 is also in the process of extension.

[0149] Therefore, before the first bellows 13 reaches the mid-contraction state, the proximity sensor 31B does not detect the extension state of the second bellows 14 (OFF), so the control unit 6 determines that the proximity sensor 31B has not turned ON. Based on this determination, at the moment t46 when the first bellows 13 reaches the mid-contraction state, the second determination based on the control unit 6 is not performed, and therefore, pressure reduction control is not performed during the next extension of the second bellows 14.

[0150] Next, at time t46, when proximity sensor 29A detects the (ON) mid-contraction state of the first bellows 13, control unit 6 determines whether proximity sensor 31B has detected the (ON) extension state of the second bellows 14 (first determination). Here, at time t46, proximity sensor 31B does not detect the (OFF) extension state of the second bellows 14, therefore control unit 6 determines that proximity sensor 31B has not turned ON. Based on this determination result, as described later, control unit 6 executes the next boost control when the second bellows 14 extends again (time t50 to time t51).

[0151] If the control unit 6 determines that the proximity sensor 31B has not turned ON, it waits until the proximity sensor 31B turns ON (the second bellows 14 becomes extended), or until the moment t46 when the proximity sensor 29A turns ON has elapsed for a predetermined calculation time, at moment t47 (the first bellows 13 becomes retracted). Here, as described above, the extension speed of the second bellows 14 slows down, and the extension time of the second bellows 14 becomes too long, so that the moment t47 when the first bellows 13 becomes retracted is reached before the second bellows 14 reaches the extended state.

[0152] At time t47 when the first bellows 13 reaches the contracted state, control unit 6 demagnetizes solenoid 4a of the first solenoid valve 4 and energizes solenoid 4b. If solenoid 4b of the first solenoid valve 4 is energized, the first bellows 13 begins to extend from the contracted state, as described above. Furthermore, the drive control and pressure reduction control of the first bellows 13 based on control unit 6 after time t47 are... Figure 6 The time t27 is the same after that, so the explanation is omitted.

[0153] At time t47 when the first bellows 13 reaches the contracted state, the control unit 6 further determines whether the proximity sensor 31B has detected (ON) the extension state of the second bellows 14 (third determination). Here, as described above, at time t47, the second bellows 14 has not reached the extension state, therefore the control unit 6 determines that the proximity sensor 31B has not turned ON. Based on this determination result, as will be described later, the control unit 6 resets the lower limit of the adjustment range based on the air pressure of the second electric pressure regulating valve 52 during the next extension of the second bellows 14 (time t50 to time t51).

[0154] Next, at time t48 when proximity sensor 31B detects the extension state of the second bellows 14, control unit 6 demagnetizes the solenoid 5b of the second solenoid valve 5 and energizes the solenoid 5a. If the solenoid 5a of the second solenoid valve 5 is energized, as described above, the second bellows 14 begins to retract from its extension state during the mid-extension state of the first bellows 13. Then, at time t50 after a predetermined calculation time has elapsed from time t49 when proximity sensor 31A detects the mid-retraction state of the second bellows 14, control unit 6 demagnetizes the solenoid 5a of the second solenoid valve 5 and energizes the solenoid 5b. If the solenoid 5b of the second solenoid valve 5 is energized, as described above, pressurized air generated in air supply device 2 is supplied to the second intake side air chamber 26B of the second drive unit 28.

[0155] At this time, the first determination made by the control unit 6 at time t46 is negative (it is determined that the proximity sensor 31B has not turned ON), so the control unit 6 performs the next pressure boosting control of the second electric pressure regulating valve 52 in a manner that increases the air pressure of the pressurized air supplied to the second intake side air chamber 26B.

[0156] Specifically, firstly, the control unit 6 determines the degree of air pressure increase so that the air pressure of the pressurized air supplied to the second intake air chamber 26B is higher than the air pressure P24 of the pressurized air supplied to the second intake air chamber 26B during the previous extension of the second bellows 14 (times t45 to t48). Here, the control unit 6 determines the degree of increase, for example, by setting the air pressure higher than the air pressure P24 after pressure reduction control but lower than the air pressure P21 before pressure reduction control (value P23). Furthermore, the control unit 6 controls the second electric pressure regulating valve 52 so that the air pressure of the pressurized air supplied to the second intake air chamber 26B becomes the determined value P23. As a result, the second bellows 14 begins its extension operation from the contracted state. Its extension speed is faster than the extension speed during the previous extension operation of the second bellows 14.

[0157] Furthermore, the control unit 6 makes a third determination at time t47, which results in a negative determination (it is determined that the proximity sensor 31B has not turned ON), and therefore resets the lower limit of the adjustment range based on the air pressure of the second electric pressure regulating valve 52.

[0158] Specifically, the control unit 6 sets the lower limit value Pd of the air pressure adjustment range based on the second electric pressure regulating valve 52 to an air pressure higher than the value P24 (here, value P23) of the pressurized air supplied to the second intake side air chamber 26B through pressure reduction control during the previous extension of the second bellows 14 (time t45 to time t48). Furthermore, the resetting of this lower limit value is preferably performed in the next pressure boosting control before the start of control of the second electric pressure regulating valve 52.

[0159] Next, at time t51 when proximity sensor 29A detects that the first bellows 13 is in a contracted state (ON), control unit 6 determines whether proximity sensor 31B has detected that the second bellows 14 is in an extended state (first determination). Here, as described above, the extension speed of the second bellows 14 increases, and the extension time of the second bellows 14 shortens, so that the second bellows 14 reaches an extended state at time t51. Therefore, proximity sensor 31B detects the extended state of the second bellows 14 at time t51, and control unit 6 determines that proximity sensor 31B is ON. Based on this determination result, control unit 6 does not perform the next boost control when the second bellows 14 extends again.

[0160] Furthermore, during the subsequent extension of the second bellows 14, the lower limit value Pd, reset in the aforementioned manner, is used as the lower limit value for the adjustment range of the air pressure based on the second electric pressure regulating valve 52. Therefore, even if pressure reduction control is performed during the subsequent extension of the second bellows 14, the air pressure reduced by this pressure reduction control will not fall below the lower limit value Pd.

[0161] exist Figure 7 In the control example, based on the result of the third determination performed at time t47, the lower limit of the air pressure adjustment range based on the second electric pressure regulating valve 52 is reset during the next extension of the second bellows 14 (times t50 to t51). However, it is also possible not to reset the lower limit during the next extension of the second bellows 14, but to do so during the next extension of the second bellows 14. The reason is that when the second bellows 14 extends again, the next pressure boost control is performed in the above manner, and the air pressure is increased by utilizing the second electric pressure regulating valve 52 even without resetting the lower limit.

[0162] When the lower limit value is reset during the extension of the second bellows 14 after the next major extension, the reset lower limit value Pd is used as the lower limit value of the adjustment range based on the air pressure of the second electric pressure regulating valve 52 during the extension of the second bellows 14 after the next major extension. Therefore, even if pressure reduction control is performed during the extension of the second bellows 14 after the next major extension, the air pressure reduced by this pressure reduction control will not be lower than the lower limit value Pd. Furthermore, the reset of the lower limit value may not be performed during the next and next major extensions of the second bellows 14, but only during the extension of the second bellows 14 after the next major extension.

[0163] exist Figure 7 In the control example, the case of resetting the lower limit of the adjustment range of the air pressure based on the second electric pressure regulating valve 52 is explained, but the case of resetting the lower limit of the adjustment range of the air pressure based on the first electric pressure regulating valve 51 is also described above, so the explanation is omitted.

[0164] [Specific example 1 of current boost control]

[0165] Figure 8 This is a timing diagram illustrating a specific example 1 of the current boost control performed in the drive control using control unit 6. Specific example 1 is... Figure 5 A variation thereof, where the current boost control is performed in conjunction with the next boost control. Below, refer to... Figure 1 as well as Figure 8 Here, we will explain a specific example 1 of the current boost control executed by control unit 6. Figure 5 Similarly, the description will be given from the state where the first bellows 13 is in the contraction action (exhausting) and the second bellows 14 is in the extension action (inhaling).

[0166] At time t61, when proximity sensor 29A detects the first bellows 13 in a mid-contraction state (ON), control unit 6 determines whether proximity sensor 31B has detected the second bellows 14 in an extension state (ON) (first determination). Here, at time t61, proximity sensor 31B does not detect the second bellows 14 in an extension state (OFF), therefore control unit 6 determines that proximity sensor 31B has not turned ON. Based on this determination result, as described above, control unit 6 executes the next boost control when the second bellows 14 extends again (time t66 to time t67).

[0167] Furthermore, when the control unit 6 determines that the proximity sensor 31B is not ON, it performs current pressure boosting control on the second electric pressure regulating valve 52 in a manner that gradually increases the air pressure of the pressurized air supplied to the second intake air chamber 26B at the current time t61. Specifically, the control unit 6 controls the second electric pressure regulating valve 52 in a manner that gradually increases the air pressure of the pressurized air supplied to the second intake air chamber 26B from the value P21 at the current time t61. As a result, the elongation speed of the second bellows 14, which is elongating at the current time t61, gradually increases over time.

[0168] Control unit 6 continues current boost control until proximity sensor 31B turns ON. Therefore, the elongation speed of the extending second bellows 14 increases until proximity sensor 31B turns ON, thus enabling the second bellows 14 to rapidly elongate from the current time t61 to the extended state. As a result, the time t62 at which the second bellows 14 reaches the extended state (the time proximity sensor 31B turns ON) is later than the time t62 when current boost control was not performed. Figure 5 The moment t2 when the second bellows 14 in the middle changes to the elongated state is advanced. Furthermore, regarding the time from... Figure 8 The control performed between time t62 and time t63, and Figure 5 The control performed during the period from time t2 to time t3 is the same, so the explanation is omitted.

[0169] At time t64, if proximity sensor 31A detects the second bellows 14 in a mid-contraction state (ON), control unit 6 determines whether proximity sensor 29B has detected the first bellows 13 in an extension state (ON) (first determination). Here, at time t64, proximity sensor 29B does not detect the first bellows 13 in an extension state (OFF), therefore control unit 6 determines that proximity sensor 29B has not turned ON. Based on this determination result, as described above, control unit 6 executes the next boost control when the first bellows 13 extends again (time t68 to time t69).

[0170] Furthermore, when the control unit 6 determines that the proximity sensor 29B is not ON, it performs current pressure boosting control on the first electric pressure regulating valve 51 in a manner that gradually increases the air pressure of the pressurized air supplied to the first intake-side air chamber 26A at the current time t64. Specifically, the control unit 6 controls the first electric pressure regulating valve 51 to gradually increase the air pressure of the pressurized air supplied to the first intake-side air chamber 26A from the value P11 at the current time t64. As a result, the elongation speed of the first bellows 13, which is elongating at the current time t64, gradually increases over time.

[0171] Control unit 6 keeps proximity sensor 29B under current boost control until it becomes ON. Therefore, the elongation speed of the first bellows 13, which is in the elongation phase, increases until proximity sensor 29B becomes ON, thus enabling the first bellows 13 to rapidly elongate from the current time t64 to the elongated state. As a result, the time t65 at which the first bellows 13 becomes elongated (the time proximity sensor 29B becomes ON) is later than the time t65 when current boost control was not performed. Figure 5 The moment t5 when the first bellows 13 in the middle becomes elongated is advanced. Figure 8 Control and Figure 5 The control performed after time t5 is the same, so the explanation is omitted.

[0172] Furthermore, in Specific Example 1, the control unit 6 performs current boost control at the moment t61 when making the first determination, but it can perform current boost control at any time during the period from that moment t61 to when the first bellows 13 becomes elongated.

[0173] Furthermore, the control unit 6 may use the first determination, which serves as the basis for determining the next boost control, as the basis for determining the current boost control. However, it may also make the determination independently of the first determination. For example, the control unit 6 may make the determination at time t63 when the first bellows 13 reaches the contracted state. In this case, the second bellows 14, which is in the extension state at time t63, can be rapidly extended to the extended state.

[0174] [Specific example 2 of current boost control]

[0175] Figure 9 This is a timing diagram illustrating Example 2 of the current boost control performed in the drive control using control unit 6. Example 2 is... Figure 7 In a modified example, after buck control is performed, the current boost control is performed in conjunction with the reset of the lower limit value. Below, refer to... Figure 1 as well as Figure 9 Example 2 will be given regarding the current boost control executed by control unit 6. Furthermore, regarding the... Figure 9 Control performed between time t80 and time t86, and from Figure 7 The control performed during the period from time t40 to time t46 is the same, so the explanation is omitted.

[0176] At time t87 when the first bellows 13 reaches the contracted state, the control unit 6 determines whether the proximity sensor 31B has detected (ON) the extension state of the second bellows 14 (third determination). Here, at time t87, the second bellows 14 has not reached the extension state, so the control unit 6 determines that the proximity sensor 31B has not turned ON. Based on this determination result, as described above, the control unit 6 resets the lower limit of the adjustment range based on the air pressure of the second electric pressure regulating valve 52 at the next extension of the second bellows 14 (time t90 to time t91).

[0177] Furthermore, when the control unit 6 determines that the proximity sensor 31B is not ON, it performs current pressure boosting control on the second electric pressure regulating valve 52 at the current time t87 in a manner that gradually increases the air pressure of the pressurized air supplied to the second intake air chamber 26B. Specifically, the control unit 6 controls the second electric pressure regulating valve 52 to gradually increase the air pressure of the pressurized air supplied to the second intake air chamber 26B from the value P24 at the current time t87. As a result, the elongation speed of the second bellows 14, which is elongating at the current time t87, gradually increases over time.

[0178] Control unit 6 continues current boost control until proximity sensor 31B turns ON. Therefore, the elongation speed of the second bellows 14, which is in the elongation phase, increases until proximity sensor 31B turns ON, thus enabling the second bellows 14 to rapidly elongate from the current time t87 to the elongated state. As a result, the time t88 at which the second bellows 14 reaches the elongated state (the time proximity sensor 31B turns ON) is later than the time t88 when current boost control was not performed. Figure 7 The moment t48 when the second bellows 14 in the middle becomes elongated is advanced.

[0179] Figure 9 The control of the first bellows 13 after time t87 and Figure 7 After time t47 ( Figure 6 The control is the same after time t27, therefore the explanation is omitted. Additionally, Figure 9 The control of the second bellows 14 after time t88 and Figure 7 The control after time t48 is the same, therefore the explanation is omitted. Additionally, Figure 9 The current pressure boosting control of the second electric pressure regulating valve 52 is described above, but the current pressure boosting control of the first electric pressure regulating valve 51 is also described above, so the description is omitted.

[0180] Furthermore, in Specific Example 2, the control unit 6 may serve as the third determination for resetting the lower limit value, which is also used as the determination for executing the current boost control. However, it may also be performed independently of the third determination to determine the current boost control. For example, the control unit 6 may make the determination at time t86 when the first bellows 13 reaches the mid-contraction state. In this case, the control unit 6 may execute the current boost control at time t86 when the determination is made, or it may execute the current boost control at any time between time t86 and the first bellows 13 becoming extended.

[0181] [Effects of this implementation method]

[0182] As described above, in the bellows pump device 1 according to this embodiment, when the first bellows 13 (second bellows 14) is contracted to the mid-contraction state, sometimes the second bellows 14 (first bellows 13) does not extend to the extended state. In this case, the control unit 6 performs a next pressurization control when the second bellows 14 (first bellows 13) extends again, causing the air pressure of the pressurized air supplied to the second intake air chamber 26B (first intake air chamber 26A) of the second drive unit 28 (first drive unit 27) to increase. As a result, when the extension time of the second bellows 14 (first bellows 13) is prolonged, the air pressure of the pressurized air used to extend the second bellows 14 (first bellows 13) can be automatically reset to a higher value. As a result, the elongation time of the second bellows 14 (the first bellows 13) is shortened in the next operation, thus suppressing the pulsation on the discharge side of the bellows pump device 1 caused by the extension of its elongation time.

[0183] Furthermore, when the first bellows 13 (second bellows 14) is contracted to its mid-contraction state, and the second bellows 14 (first bellows 13) has not yet extended to its extended state, the control unit 6 performs current pressure boosting control on the second bellows 14 (first bellows 13) that is currently extended, so that the air pressure of the pressurized air supplied to the second intake air chamber 26B (first intake air chamber 26A) of the second drive unit 28 (first drive unit 27) gradually increases. Therefore, when the extension time of the second bellows 14 (first bellows 13) is prolonged, the air pressure of the pressurized air used to extend the second bellows 14 (first bellows 13) can be automatically reset in a manner that gradually increases to a higher value. As a result, the extension time of the second bellows 14 (first bellows 13) at the current moment is shortened, thus suppressing the pulsation on the discharge side of the bellows pump device 1 caused by the extended extension time.

[0184] Furthermore, by performing the current pressure boost control, the second bellows 14 (first bellows 13), which is currently elongating, can reliably elongate to its elongated state without stopping during the elongation process. As a result, the next pressure boost control can be reliably performed during the next elongation of the second bellows 14 (first bellows 13).

[0185] When the first bellows 13 (second bellows 14) is contracted to its mid-contraction state, the second bellows 14 (first bellows 13) may extend for a duration greater than or equal to a predetermined time. In this case, the control unit 6 performs pressure reduction control during the next extension of the second bellows 14 (first bellows 13), reducing the air pressure of the pressurized air supplied to the second intake air chamber 26B (first intake air chamber 26A) of the second drive unit 28 (first drive unit 27). As a result, when the extension time of the second bellows 14 (first bellows 13) is shortened to a duration greater than or equal to the desired time, the air pressure of the pressurized air used to extend the second bellows 14 (first bellows 13) can be automatically reset to a lower value. Consequently, the extension time of the second bellows 14 (first bellows 13) is extended and the extension speed is reduced, thus suppressing the generation of impact pressure and cavitation.

[0186] When the control unit 6 performs pressure reduction control, sometimes the second bellows 14 (first bellows 13) does not extend to its extended state when the first bellows 13 (second bellows 14) is contracted to its contracted state. In this case, the control unit 6 resets the lower limit of the adjustment range based on the air pressure of the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) for the next extension of the second bellows 14 (first bellows 13) to be higher than the air pressure during the previous extension of the other bellows. As a result, it is possible to limit the air pressure adjusted by the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) from falling below the lower limit Pd during the next extension of the second bellows 14 (first bellows 13), thus preventing the extension time of the second bellows 14 (first bellows 13) from becoming too long. Consequently, it is possible to suppress the deterioration of the pulsation on the discharge side of the bellows pump device 1 caused by the extended extension time.

[0187] Furthermore, the lower limit value reset during the next elongation of the second bellows 14 (first bellows 13) is used as the lower limit value for the adjustment range based on the air pressure of the second electric pressure regulating valve 52 (first electric pressure regulating valve 51), even during the elongation of the second bellows 14 (first bellows 13) after the next large elongation. Therefore, even when pressure reduction control is performed during the elongation of the second bellows 14 (first bellows 13) after the next large elongation, the reduced air pressure due to this pressure reduction control will not fall below the lower limit value Pd. Therefore, by extending the elongation time of the second bellows 14 (first bellows 13) due to pressure reduction control, it is possible to prevent the second bellows 14 (first bellows 13) from contracting from the extended state before it is about to become contracted. As a result, the pulsation variation on the discharge side of the bellows pump device 1 can be further suppressed.

[0188] When the first bellows 13 (second bellows 14) contracts to its contracted state due to pressure reduction control, and the second bellows 14 (first bellows 13) has not extended to its extended state, the control unit 6 can reset the lower limit of the adjustment range based on the air pressure of the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) for the next extension of the second bellows 14 (first bellows 13) to a higher value than the air pressure for the previous extension of the other bellows. When the second bellows 14 (first bellows 13) extends again, the next pressure boost control is performed. Even without resetting the lower limit, the air pressure is increased using the second electric pressure regulating valve 52 (first electric pressure regulating valve 51), thus eliminating the need to specifically reset the lower limit for the next extension of the second bellows 14 (first bellows 13). Therefore, during the elongation of the second bellows 14 (first bellows 13) in the next major cycle, the air pressure adjusted by the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) can be limited to a lower limit value Pd, thus preventing the elongation time of the second bellows 14 (first bellows 13) from becoming too long. As a result, the pulsation on the discharge side of the bellows pump device 1 caused by the extended elongation time can be suppressed.

[0189] Furthermore, the lower limit value reset during the elongation of the second bellows 14 (first bellows 13) after the next large extension is also used as the lower limit value of the adjustment range based on the air pressure of the second electric pressure regulating valve 52 (first electric pressure regulating valve 51) during the elongation of the second bellows 14 (first bellows 13) after the next large extension. Therefore, even if pressure reduction control is performed during the elongation of the second bellows 14 (first bellows 13) after the next large extension, the air pressure reduced by this pressure reduction control will not be lower than the lower limit value Pd. Therefore, by extending the elongation time of the second bellows 14 (first bellows 13) due to pressure reduction control, it is possible to prevent the second bellows 14 (first bellows 13) from contracting from the extended state before it is about to become contracted. As a result, the pulsation variation on the discharge side of the bellows pump device 1 can be further suppressed.

[0190] Furthermore, the control unit 6 performs pressure reduction control, thereby performing current pressure increase control when the first bellows 13 (second bellows 14) is contracted to the contracted state, and when the second bellows 14 (first bellows 13) has not extended to the extended state. This causes the air pressure of the pressurized air associated with the currently extended second bellows 14 (first bellows 13) to gradually increase. This shortens the extension time of the second bellows 14 (first bellows 13) at the current moment. As a result, the pulsation variation on the discharge side of the bellows pump device 1 caused by the extended extension time can be suppressed. Additionally, incomplete intake of the transferred fluid caused by the extension of the second bellows 14 (first bellows 13) can be suppressed, thus preventing the bellows pump device 1 from stopping due to this incomplete intake.

[0191] Furthermore, by performing current pressure boost control, the second bellows 14 (first bellows 13), which is currently elongating, can reliably elongate to its elongated state without stopping midway through elongation. As a result, the lower limit value can be reliably reset during the next elongation of the second bellows 14 (first bellows 13).

[0192] The first detection unit 29 and the second detection unit 31, which are used for drive control of the first drive unit 27 and the second drive unit 28, also serve as a pair of detection units for current boost control, next boost control, and depressurization control, thus simplifying the structure of the bellows pump device 1.

[0193] [other]

[0194] In the above embodiment, the first detection unit 29 is composed of proximity sensors 29A and 29B, but it may also be composed of a displacement sensor using a laser or the like. Similarly, the second detection unit 31 is composed of proximity sensors 31A and 31B, but it may also be composed of a displacement sensor using a laser or the like.

[0195] In addition, in the above embodiment, the first detection unit 29 and the second detection unit 31 used for drive control of the first drive unit 27 and the second drive unit 28 also serve as a pair of detection units for current boost control, next boost control and buck control, but the pair of detection units may be provided differently from the first detection unit 29 and the second detection unit 31.

[0196] It should be understood that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. The scope of the invention is not limited thereto, as indicated by the claims, and is intended to include the equivalent scope of the claims and all modifications within that scope.

[0197] Explanation of the label

[0198] 1. Bellows pump unit

[0199] 6 Control Department

[0200] 13. First bellows (corrugated pipe)

[0201] 14. Second corrugated pipe (corrugated pipe)

[0202] 21A First Discharge Side Air Chamber (Discharge Side Fluid Chamber)

[0203] 21B Second Exhaust Side Air Chamber (Exhaust Side Fluid Chamber)

[0204] 26A First Intake Side Air Chamber (Intake Side Fluid Chamber)

[0205] 26B Second Intake Side Air Chamber (Intake Side Fluid Chamber)

[0206] 27. First Drive Unit (Drive Unit)

[0207] 28. Second Drive Unit (Drive Unit)

[0208] 29. First Inspection Department (Inspection Department)

[0209] 31. Second Inspection Department (Inspection Department)

[0210] 51. First Electrical Pressure Regulating Valve (Fluid Pressure Adjustment Unit)

[0211] 52. Second Electrical Pressure Regulating Valve (Fluid Pressure Adjustment Unit)

Claims

1. A bellows pump device, comprising: A pair of bellows that can extend and retract independently of each other, drawing in the fluid to be transferred by extending and expelling the fluid from the inside by contracting; A pair of drive units, each having an intake-side fluid chamber and an exhaust-side fluid chamber, wherein pressurized fluid is supplied to the intake-side fluid chamber to extend each of the bellows to a predetermined elongation state, and pressurized fluid is supplied to the exhaust-side fluid chamber to contract each of the bellows to a predetermined contraction state; as well as The control unit performs drive control on the pair of drive units in such a way that it causes the other bellows to retract from the extended state just before one of the bellows is about to enter the retracted state. The bellows pump device has: A pair of detection units that detect the expansion and contraction states of each of the bellows; and A pair of fluid pressure regulating units adjust the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of each of the drive units. Based on the detection signals of each of the pair of detection units, the control unit determines whether the other bellows is in the elongated state when the one bellows is in the mid-contraction state just before it becomes the contracted state. If the determination result is negative, the control unit controls the next pressure increase control of the fluid pressure adjustment unit corresponding to the drive unit that causes the other bellows to elongate in a manner that increases the fluid pressure when the other bellows elongates next time.

2. A bellows pump device, comprising: A pair of bellows that can extend and retract independently of each other, drawing in the fluid to be transferred by extending and expelling the fluid from the inside by contracting; A pair of drive units, each having an intake-side fluid chamber and an exhaust-side fluid chamber, wherein pressurized fluid is supplied to the intake-side fluid chamber to extend each of the bellows to a predetermined elongation state, and pressurized fluid is supplied to the exhaust-side fluid chamber to contract each of the bellows to a predetermined contraction state; as well as The control unit performs drive control on the pair of drive units in such a way that it causes the other bellows to retract from the extended state just before one of the bellows is about to enter the retracted state. The bellows pump device has: A pair of detection units that detect the expansion and contraction states of each of the bellows; and A pair of fluid pressure regulating units adjust the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of each of the drive units. Based on the detection signals of each of the pair of detection units, the control unit determines whether the other bellows is in the extended state when one bellows contracts to the mid-contraction state before it becomes the contracted state, or when one bellows contracts to the contracted state. If the determination result is negative, the control unit controls the current pressure increase of the fluid pressure adjustment unit corresponding to the drive unit that extends the other bellows in a manner that gradually increases the fluid pressure associated with the extended other bellows at the current moment.

3. A bellows pump device, comprising: A pair of bellows that can extend and retract independently of each other, drawing in the fluid to be transferred by extending and expelling the fluid from the inside by contracting; A pair of drive units, each having an intake-side fluid chamber and an exhaust-side fluid chamber, wherein pressurized fluid is supplied to the intake-side fluid chamber to extend each of the bellows to a predetermined elongation state, and pressurized fluid is supplied to the exhaust-side fluid chamber to contract each of the bellows to a predetermined contraction state; as well as The control unit performs drive control on the pair of drive units in such a way that it causes the other bellows to retract from the extended state just before one of the bellows is about to enter the retracted state. The bellows pump device has: A pair of detection units that detect the expansion and contraction states of each of the bellows; and A pair of fluid pressure regulating units adjust the fluid pressure of the pressurized fluid supplied to the suction-side fluid chamber of each of the drive units. Based on the detection signals of each of the pair of detection units, the control unit determines whether the other bellows has caused the elongation state to last for a time greater than or equal to a predetermined time when the one bellows is contracted to the mid-contraction state just before it becomes the contracted state. If the determination result is positive, the control unit controls the pressure reduction of the fluid pressure adjustment unit corresponding to the drive unit that causes the other bellows to elongate in a manner that reduces the fluid pressure when the other bellows elongates next time.

4. The bellows pump device according to claim 1, wherein, Based on the detection signals of each of the pair of detection units, the control unit determines whether the other bellows has caused the elongation state to last for a time greater than or equal to a predetermined time when one bellows contracts to the mid-contraction state. If the determination result is positive, the control unit controls the pressure reduction of the fluid pressure adjustment unit corresponding to the drive unit that causes the other bellows to extend in a manner that reduces the fluid pressure when the other bellows extends again.

5. The bellows pump device according to claim 3 or 4, wherein, Based on the detection signals of the pair of detection units, the control unit determines whether the other bellows is in the extended state when the other bellows is contracted to the contracted state. If the determination result is negative, the lower limit of the fluid pressure adjustment range based on the fluid pressure adjustment unit for the next extension of the other bellows is set to be higher than the fluid pressure for the previous extension of the other bellows.

6. The bellows pump device according to claim 4, wherein, Based on the detection signals of the pair of detection units, the control unit determines whether the other bellows is in the extended state when the other bellows is contracted to the contracted state. If the determination result is negative, the lower limit of the adjustment range of the fluid pressure based on the fluid pressure adjustment unit for the extended state of the other bellows in the next subsequent period is set to be higher than the fluid pressure when the other bellows was extended in the previous period.

7. The bellows pump device according to claim 3 or 4, wherein, Based on the detection signals of each of the pair of detection units, the control unit determines whether the other bellows is in the extended state when one bellows contracts to the mid-contraction state before it becomes the contracted state, or when one bellows contracts to the contracted state. If the determination result is negative, the control unit controls the current pressure increase of the fluid pressure adjustment unit corresponding to the drive unit that extends the other bellows in a manner that gradually increases the fluid pressure associated with the extended other bellows at the current moment.

8. The bellows pump device according to any one of claims 1 to 4, wherein, The control unit performs the drive control based on each detection signal from a pair of detection units.

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