JP6367645B2 - Bellows pump device - Google Patents

Description

  The present invention relates to a bellows pump device.

In semiconductor manufacturing, chemical industry, etc., a bellows pump may be used as a pump for feeding a transfer fluid such as a chemical solution or a solvent.
In this bellows pump, for example, as described in Patent Document 1, two air chambers are formed by connecting pump cases on both sides in the left-right direction (horizontal direction) of the pump head, and the inside of each air chamber. A pair of bellows that can be expanded and contracted in the left-right direction is provided, and each bellows is contracted or expanded by alternately supplying pressurized air to each air chamber. The bellows pump is connected to a mechanical regulator that adjusts the pressurized air supplied to each air chamber to an appropriate air pressure.

  The pump head is formed with a suction passage and a discharge passage for the transfer fluid communicating with the inside of each bellows. Further, the pump head allows a flow of the transfer fluid in one direction with respect to the suction passage and the discharge passage, and is transferred in the other direction. A check valve is provided to block fluid flow. The check valve for the suction passage allows the flow of the transfer fluid from the suction passage into the bellows by being opened by the extension of the bellows, and the flow of the transfer fluid from the inside of the bellows to the suction passage by being closed by the contraction of the bellows. Is configured to prevent. The check valve for the discharge passage is closed by the extension of the bellows to prevent the flow of the transfer fluid from the discharge passage into the bellows, and is opened by the contraction of the bellows to transfer the fluid from the inside of the bellows to the discharge passage. It is comprised so that the flow of may be permitted.

  The pair of bellows are integrally connected by a tie rod. When one bellows contracts and discharges the transfer fluid to the discharge passage, the other bellows is forcibly extended at the same time and the transfer fluid is sucked from the suction passage. It is. Further, when the other bellows contracts to discharge the transfer fluid to the discharge passage, at the same time, the one bellows is forcibly extended and the transfer fluid is sucked from the suction passage.

JP 2012-211152 A

  In the bellows pump configured as described above, when pressurized air is supplied to the air chamber formed outside the bellows to contract the bellows, the stress necessary to contract the bellows increases as the contraction proceeds. It is necessary to increase the air pressure of the pressurized air supplied to the chamber. However, a mechanical regulator that adjusts the air pressure of the pressurized air cannot perform control to temporarily open the valve in order to increase the air pressure of the air chamber. For this reason, as shown in FIG. 12, while each bellows is contracting, a phenomenon occurs in which the discharge pressure of the transfer fluid gradually drops (a portion surrounded by a broken line in the figure), which causes pulsation. It was.

  This invention is made | formed in view of such a situation, and it aims at providing the bellows pump apparatus which can reduce that the discharge pressure of a transfer fluid falls at the time of contraction operation | movement of a bellows.

  The bellows pump device according to the present invention supplies compressed air to a sealed air chamber to cause the bellows disposed in the air chamber to contract and discharge a transfer fluid, and to supply pressurized air from the air chamber. A bellows pump device that draws out a transfer fluid by extending the bellows by discharging, and when the bellows contracts, the air pressure of the pressurized air supplied to the air chamber is changed to the contraction characteristics of the bellows. An electropneumatic regulator for controlling the air pressure is provided so as to increase correspondingly.

  According to the bellows pump device configured as described above, the air pressure of the pressurized air supplied to the air chamber rises corresponding to the contraction characteristics of the bellows by the electropneumatic regulator during the contraction operation of the bellows. As the bellows contracts, the air pressure of the pressurized air in the air chamber can be increased. Thereby, it can reduce that the discharge pressure of a transfer fluid falls while the bellows is shrink | contracting.

It is preferable that the electropneumatic regulator controls the air pressure using the following formula every unit time.
P = at + b
Where P is the air pressure, a is the pressure increase coefficient, t is the elapsed time of contraction of the bellows, and b is the initial air pressure.
In this case, it is possible to effectively reduce the drop in the discharge pressure of the transfer fluid while the bellows is contracted.

  In the bellows pump device, the bellows is composed of a first bellows and a second bellows that can be expanded and contracted independently of each other, and the first bellows continuously expands and contracts between the most extended state and the most contracted state. A first driving device; a second driving device that continuously expands and contracts the second bellows between a most extended state and a most contracted state; a first detection unit that detects the expanding and contracting state of the first bellows; Based on the second detection means for detecting the expansion / contraction state of the second bellows and the respective detection signals of the first and second detection means, the second bellows is most extended before the first bellows is in the most contracted state. A controller that drives and controls the first and second drive devices so that the first bellows is contracted from the most extended state before the second bellows is in the most contracted state. Preferably comprises La.

  In this case, the first bellows and the second bellows can be expanded and contracted independently from each other, and in the control unit, the second bellows is contracted from the maximum extension state before the first bellows is in the maximum contraction state, and the second bellows is Since the first bellows is driven and controlled to contract from the maximum stretched state before reaching the most contracted state, at the switching timing from contraction (discharge) to expansion (suction) of one bellows, the other bellows Since the transfer fluid is already contracted and discharged, it is possible to reduce the drop in discharge pressure at the switching timing. As a result, pulsation on the discharge side of the bellows pump device can be reduced.

  According to the bellows pump device of the present invention, it is possible to reduce the drop in the discharge pressure of the transfer fluid during the bellows contraction operation.

It is a schematic structure figure of the bellows pump device concerning the embodiment of the present invention. It is sectional drawing of a bellows pump. It is explanatory drawing which shows operation | movement of a bellows pump. It is explanatory drawing which shows operation | movement of a bellows pump. It is a block diagram which shows the internal structure of a control part. It is a time chart which shows an example of drive control of a bellows pump. It is sectional drawing which shows the state which the 2nd bellows of the maximum extension state started contraction before the 1st bellows will be in the most contracted state. It is sectional drawing which shows the state which the 1st bellows of the maximum extension state started contraction before the 2nd bellows will be in the most contracted state. It is a graph which shows an example of control of the air pressure of the 1st and 2nd electropneumatic regulator. It is a graph which shows the discharge pressure of the transfer fluid discharged from a bellows pump. It is a schematic block diagram which shows the modification of a bellows pump apparatus. It is a graph which shows the discharge pressure of the transfer fluid discharged from the conventional bellows pump.

Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[Overall configuration of bellows pump]
FIG. 1 is a schematic configuration diagram of a bellows pump device according to an embodiment of the present invention. The bellows pump device according to the present embodiment is used, for example, when supplying a certain amount of transfer fluid such as a chemical solution or a solvent in a semiconductor manufacturing apparatus. This bellows pump device includes a bellows pump 1, an air supply device 2 such as an air compressor that supplies pressurized air (working fluid) to the bellows pump 1, a mechanical regulator 3 that adjusts the air pressure of the pressurized air, and Two first and second electropneumatic regulators 51 and 52, two first and second switching valves 4 and 5, and a control unit 6 that controls driving of the bellows pump 1 are provided.

FIG. 2 is a cross-sectional view of the bellows pump according to the embodiment of the present invention.
The bellows pump 1 of the present embodiment includes a pump head 11, a pair of pump cases 12 attached to both sides of the pump head 11 in the left-right direction (horizontal direction), and the right and left sides of the pump head 11 inside each pump case 12. Two first and second bellows 13, 14 attached to the side surface in the direction, and four check valves 15, 16 attached to the side surface in the left-right direction of the pump head 11 inside each bellows 13, 14, It has.

[Composition of bellows]
The first and second bellows 13 and 14 are formed in a bottomed cylindrical shape from a fluororesin such as PTFE (polytetrafluoroethylene) or PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), and open end portions thereof Are integrally fixed to the side surface of the pump head 11 in an airtight manner. Each peripheral wall of the 1st and 2nd bellows 13 and 14 is formed in the bellows shape, and it is constituted so that expansion and contraction is possible in the horizontal direction independently of each other. Specifically, the first and second bellows 13, 14 are in a fully extended state where an outer surface of a working plate 19 described later comes into contact with an inner side surface of the bottom wall portion 12 a of the pump case 12 and a piston body 23 described later. The inner side surface expands and contracts between the most contracted state contacting the outer side surface of the bottom wall portion 12 a of the pump case 12.
An operation plate 19 is fixed to the outer surfaces of the bottom portions of the first and second bellows 13 and 14 together with one end of the connecting member 20 by bolts 17 and nuts 18.

[Configuration of pump case]
The pump case 12 is formed in a bottomed cylindrical shape, and the opening peripheral edge thereof is airtightly fixed to the flange portion 13a (14a) of the corresponding bellows 13 (14). As a result, a discharge-side air chamber 21 that is kept airtight is formed inside the pump case 12.
The pump case 12 is provided with an intake / exhaust port 22, and the intake / exhaust port 22 is connected to the air supply device 2 via the switching valve 4 (5), the electropneumatic regulator 51 (52), and the mechanical regulator 3. (See FIG. 1). As a result, pressurized air is supplied from the air supply device 2 to the inside of the discharge-side air chamber 21 through the mechanical regulator 3, the electropneumatic regulator 51 (52), the switching valve 4 (5), and the intake / exhaust port 22. Thus, the bellows 13 (14) contracts.

  Further, the connecting member 20 is supported on the bottom wall portion 12a of each pump case 12 so as to be slidable in the horizontal direction, and a piston body 23 is fixed to the other end of the connecting member 20 by a nut 24. ing. The piston body 23 is supported so as to be slidable in the horizontal direction while maintaining an airtight state with respect to an inner peripheral surface of a cylindrical cylinder body 25 integrally provided on the outer side surface of the bottom wall portion 12a. Yes. Thereby, the space surrounded by the bottom wall portion 12a, the cylinder body 25, and the piston body 23 is a suction-side air chamber 26 in which an airtight state is maintained.

The cylinder body 25 is formed with an intake / exhaust port 25a communicating with the suction-side air chamber 26. The intake / exhaust port 25a includes the switching valve 4 (5), the electropneumatic regulator 51 (52), and a mechanical regulator. 3 is connected to the air supply device 2 (see FIG. 1). Thus, pressurized air is supplied from the air supply device 2 to the inside of the suction side air chamber 26 through the mechanical regulator 3, the electropneumatic regulator 51 (52), the switching valve 4 (5), and the intake / exhaust port 25a. Thus, the bellows 13 (14) is extended.
A leakage sensor 40 for detecting leakage of the transfer fluid to the discharge-side air chamber 21 is attached below the bottom wall portion 12a of each pump case 12.

  In the bellows pump device according to the present embodiment, the time until the entire inside of the suction side air chamber 26 is filled with the pressurized air is the time until the whole inside of the discharge side air chamber 21 is filled with the pressurized air. It is shorter than time. That is, the extension time (suction time) for the bellows 13 (14) to extend from the most contracted state to the most extended state is less than the contraction time (discharge time) for the bellows 13 (14) to contract from the most extended state to the most contracted state. Is also shorter.

With the above configuration, the first bellows 13 is formed by the pump case 12 in which the discharge side air chamber 21 on the left side of FIG. 2 is formed, and the piston body 23 and the cylinder body 25 that form the suction side air chamber 26 on the left side of FIG. A first air cylinder portion (first driving device) 27 is configured to continuously expand and contract between the most extended state and the most contracted state.
Further, the second bellows 14 is extended most by the pump case 12 in which the discharge side air chamber 21 on the right side of FIG. 2 is formed and the piston body 23 and the cylinder body 25 in which the suction side air chamber 26 on the right side of FIG. 2 is formed. A second air cylinder portion (second drive device) 28 is configured to continuously expand and contract between the state and the most contracted state.

  A pair of proximity sensors 29A and 29B are attached to the cylinder body 25 of the first air cylinder portion 27, and a detection plate 30 to be detected by the proximity sensors 29A and 29B is attached to the piston body 23. The plate 30 to be detected is detected by reciprocating with the piston body 23 and alternately approaching the proximity sensors 29A and 29B.

  The proximity sensor 29 </ b> A is a first most contraction detection unit that detects the most contracted state of the first bellows 13, and is disposed at a position where the detected plate 30 is detected when the first bellows 13 is in the most contracted state. The proximity sensor 29 </ b> B is a first maximum extension detection unit that detects the maximum extension state of the first bellows 13, and is disposed at a position to detect the detection plate 30 when the first bellows 13 is in the maximum extension state. Detection signals from the proximity sensors 29A and 29B are transmitted to the control unit 6. In the present embodiment, the pair of proximity sensors 29 </ b> A and 29 </ b> B constitutes a first detection unit 29 that detects the expansion / contraction state of the first bellows 13.

  Similarly, a pair of proximity sensors 31A and 31B are attached to the cylinder body 25 of the second air cylinder portion 28, and a detection plate 32 detected by the proximity sensors 31A and 31B is attached to the piston body 23. Yes. The detected plate 32 is detected by reciprocating together with the piston body 23 to alternately approach the proximity sensors 31A and 31B.

  The proximity sensor 31 </ b> A is a second most contraction detection unit that detects the most contracted state of the second bellows 14, and is disposed at a position where the detected plate 32 is detected when the second bellows 14 is in the most contracted state. The proximity sensor 31B is a second maximum extension detection unit that detects the maximum extension state of the second bellows 14, and is disposed at a position to detect the detection plate 32 when the second bellows 14 is in the maximum extension state. Detection signals from the proximity sensors 31A and 31B are transmitted to the control unit 6. In the present embodiment, the pair of proximity sensors 31 </ b> A and 31 </ b> B constitute the second detection means 31 that detects the expansion / contraction state of the second bellows 14.

  The compressed air generated by the air supply device 2 is detected by the pair of proximity sensors 29A and 29B of the first detection means 29 alternately, so that the suction side air chamber of the first air cylinder portion 27 is detected. 26 and the discharge-side air chamber 21 are alternately supplied. As a result, the first bellows 13 continuously expands and contracts.

  Further, the pressurized air is detected by the pair of proximity sensors 31A and 31B of the second detection means 31 alternately, so that the suction side air chamber 26 and the discharge side air of the second air cylinder portion 28 are detected. Alternately supplied to the chamber 21. As a result, the second bellows 14 continuously expands and contracts. At that time, the expansion operation of the second bellows 14 is performed mainly when the first bellows 13 is contracted, and the contraction operation of the second bellows 14 is performed mainly when the first bellows 13 is expanded. As described above, the first bellows 13 and the second bellows 14 alternately extend and contract, whereby the suction and discharge of the transfer fluid into the bellows 13 and 14 are alternately performed, and the transfer fluid is It is to be transferred.

[Configuration of pump head]
The pump head 11 is made of a fluororesin such as PTFE or PFA. Inside the pump head 11, a suction passage 34 and a discharge passage 35 for the transfer fluid are formed. The suction passage 34 and the discharge passage 35 open at the outer peripheral surface of the pump head 11, and are provided on the outer peripheral surface. The suction port and the discharge port (both not shown) are connected. The suction port is connected to a transfer fluid storage tank or the like, and the discharge port is connected to a transfer fluid destination. In addition, the suction passage 34 and the discharge passage 35 respectively branch toward the left and right side surfaces of the pump head 11, and have a suction port 36 and a discharge port 37 that open on both the left and right side surfaces of the pump head 11. Each suction port 36 and each discharge port 37 communicate with the inside of the bellows 13 and 14 via the check valves 15 and 16, respectively.

[Check valve configuration]
Each suction port 36 and each discharge port 37 are provided with check valves 15 and 16.
The check valve 15 (hereinafter also referred to as “suction check valve”) attached to the suction port 36 includes a valve case 15a, a valve body 15b accommodated in the valve case 15a, and a valve closing direction of the valve body 15b. And a compression coil spring 15c for urging the spring. The valve case 15a is formed in a bottomed cylindrical shape, and a through hole 15d communicating with the inside of the bellows 13 and 14 is formed in the bottom wall. The valve body 15b closes (closes) the suction port 36 by the biasing force of the compression coil spring 15c, and opens (opens) the suction port 36 when back pressure due to the flow of the transfer fluid accompanying expansion and contraction of the bellows 13 and 14 acts. It is supposed to be.
As a result, the suction check valve 15 opens when the bellows 13 and 14 on which the suction check valve 15 is disposed is extended, and the fluid is transferred in the direction (one direction) from the suction passage 34 toward the inside of the bellows 13 and 14. When the bellows 13 and 14 are contracted, the valve is closed to prevent the backflow of the transferred fluid from the inside of the bellows 13 and 14 toward the suction passage 34 (the other direction).

  A check valve 16 (hereinafter also referred to as “discharge check valve”) attached to the discharge port 37 includes a valve case 16a, a valve body 16b accommodated in the valve case 16a, and a valve closing direction of the valve body 16b. And a compression coil spring 16c for urging the spring. The valve case 16a is formed in a bottomed cylindrical shape, and a through-hole 16d communicating with the inside of the bellows 13 and 14 is formed in the bottom wall. The valve body 16b closes (closes) the through hole 16d of the valve case 16a by the urging force of the compression coil spring 16c, and when the back pressure due to the flow of the transfer fluid accompanying expansion and contraction of the bellows 13 and 14 acts, the valve case 16a penetrates. The hole 16d is opened (opened).

  As a result, the discharge check valve 16 opens when the bellows 13 and 14 on which the discharge check valve 16 is disposed contracts, and transfers fluid in a direction (one direction) from the inside of the bellows 13 and 14 toward the discharge passage 35. Is allowed to flow out, and is closed when the bellows 13 and 14 are extended to prevent the backflow of the transfer fluid from the discharge passage 35 toward the inside of the bellows 13 and 14 (in the other direction).

[Bellows pump operation]
Next, operation | movement of the bellows pump 1 of this embodiment is demonstrated with reference to FIG.3 and FIG.4. 3 and 4 show the configurations of the first and second bellows 13 and 14 in a simplified manner.
As shown in FIG. 3, when the first bellows 13 contracts and the second bellows 14 extends, the valve bodies of the suction check valve 15 and the discharge check valve 16 mounted on the left side of the pump head 11 in the figure. 15b and 16b receive pressure from the transfer fluid in the first bellows 13 and move to the right side of the valve cases 15a and 16a in the drawing. As a result, the suction check valve 15 is closed and the discharge check valve 16 is opened, so that the transfer fluid in the first bellows 13 is discharged from the discharge passage 35 to the outside of the pump.

  On the other hand, the valve bodies 15b, 16b of the suction check valve 15 and the discharge check valve 16 mounted on the right side of the pump head 11 in the drawing are shown in the drawing of the valve cases 15a, 16a by the suction action by the second bellows 14, respectively. Move to the right respectively. Accordingly, the suction check valve 15 is opened, the discharge check valve 16 is closed, and the transfer fluid is sucked into the second bellows 14 from the suction passage 34.

  Next, as shown in FIG. 4, when the first bellows 13 is extended and the second bellows 14 is contracted, the suction check valve 15 and the discharge check valve 16 mounted on the right side of the pump head 11 in the drawing are used. Each valve body 15b, 16b receives pressure from the transfer fluid in the second bellows 14, and moves to the left side of each valve case 15a, 16a in the figure. As a result, the suction check valve 15 is closed and the discharge check valve 16 is opened, so that the transfer fluid in the second bellows 14 is discharged from the discharge passage 35 to the outside of the pump.

On the other hand, the valve bodies 15b and 16b of the suction check valve 15 and the discharge check valve 16 mounted on the left side of the pump head 11 in the figure are shown in the figure of the valve cases 15a and 16a by the suction action of the first bellows 13, respectively. Move to the left. As a result, the suction check valve 15 is opened, the discharge check valve 16 is closed, and the transfer fluid is sucked into the first bellows 13 from the suction passage 34.
By repeating the above operation, the left and right bellows 13 and 14 can alternately suck and discharge the transfer fluid.

[Configuration of switching valve]
In FIG. 1, the first switching valve 4 switches supply / exhaust of pressurized air from the air supply device 2 to the discharge-side air chamber 21 and the suction-side air chamber 26 of the first air cylinder portion 27. It consists of a three-position electromagnetic switching valve having solenoids 4a and 4b. Each solenoid 4a, 4b is excited by receiving a command signal from the control unit 6. In addition, although the 1st switching valve 4 of this embodiment consists of a 3 position electromagnetic switching valve, it may be a 2 position electromagnetic switching valve which does not have a neutral position.

  The first switching valve 4 is held in a neutral position when both solenoids 4a and 4b are demagnetized, and the discharge side air chamber 21 (intake / exhaust port 22) and intake of the first air cylinder portion 27 from the air supply device 2 are sucked. Supply of pressurized air to the side air chamber 26 (intake / exhaust port 25a) is shut off, and the discharge side air chamber 21 and the suction side air chamber 26 of the first air cylinder portion 27 are both opened to communicate with the atmosphere. ing.

  Further, when the solenoid 4a is excited, the first switching valve 4 switches to the lower position in the figure, and pressurized air is supplied from the air supply device 2 to the discharge side air chamber 21 of the first air cylinder portion 27. The At that time, the suction side air chamber 26 of the first air cylinder portion 27 is opened in communication with the atmosphere. Thereby, the 1st bellows 13 can be shrunk.

  Further, when the solenoid 4b is excited, the first switching valve 4 switches to the upper position in the figure, and pressurized air is supplied from the air supply device 2 to the suction side air chamber 26 of the first air cylinder portion 27. The At that time, the discharge-side air chamber 21 of the first air cylinder portion 27 is opened in communication with the atmosphere. Thereby, the 1st bellows 13 can be extended.

  The second switching valve 5 switches the supply and discharge of pressurized air from the air supply device 2 to the discharge side air chamber 21 and the suction side air chamber 26 of the second air cylinder portion 28. For example, a pair of solenoids 5a, It consists of a three-position electromagnetic switching valve having 5b. Each solenoid 5a, 5b is excited by receiving a command signal from the control unit 6. In addition, although the 2nd switching valve 5 of this embodiment consists of a 3 position electromagnetic switching valve, it may be a 2 position electromagnetic switching valve which does not have a neutral position.

  The second switching valve 5 is held in a neutral position when both solenoids 5a and 5b are demagnetized, and the discharge side air chamber 21 (intake / exhaust port 22) of the second air cylinder portion 28 and the intake air are supplied from the air supply device 2. The supply of pressurized air to the side air chamber 26 (intake / exhaust port 25a) is shut off, and the discharge side air chamber 21 and the suction side air chamber 26 of the second air cylinder portion 28 are both opened to communicate with the atmosphere. ing.

  Further, when the solenoid 5a is excited, the second switching valve 5 switches to the lower position in the figure, and pressurized air is supplied from the air supply device 2 to the discharge side air chamber 21 of the second air cylinder portion 28. The At that time, the suction side air chamber 26 of the second air cylinder portion 28 is opened in communication with the atmosphere. Thereby, the 2nd bellows 14 can be shrunk.

  Furthermore, when the solenoid 5b is excited, the second switching valve 5 switches to the upper position in the figure, and pressurized air is supplied from the air supply device 2 to the suction side air chamber 26 of the second air cylinder portion 28. The At that time, the discharge-side air chamber 21 of the second air cylinder portion 28 is opened in communication with the atmosphere. Thereby, the 2nd bellows 14 can be extended.

  In FIG. 1, a first quick exhaust valve 61 is adjacent to the discharge side air chamber 21 between the discharge side air chamber 21 (intake and exhaust port 22) of the first air cylinder portion 27 and the first switching valve 4. Has been placed. The first quick exhaust valve 61 has an exhaust port 61a for discharging pressurized air, allows the flow of pressurized air from the first switching valve 4 to the discharge side air chamber 21, and discharge side air chambers. The pressurized air that has flowed out from the exhaust gas 21 is discharged from the exhaust port 61a. Thereby, the pressurized air in the discharge side air chamber 21 can be quickly discharged from the first quick exhaust valve 61 without passing through the first switching valve 4.

  Similarly, a second quick exhaust valve 62 is disposed adjacent to the discharge side air chamber 21 between the discharge side air chamber 21 (intake / exhaust port 22) of the second air cylinder portion 28 and the second switching valve 5. Has been. The second quick exhaust valve 62 has an exhaust port 62a for discharging pressurized air, allows the flow of pressurized air from the second switching valve 5 to the discharge side air chamber 21, and discharge side air chambers. The pressurized air flowing out from the gas outlet 21 is discharged from the exhaust port 62a. Thereby, the pressurized air in the discharge side air chamber 21 can be quickly discharged from the second quick exhaust valve 62 without passing through the second switching valve 5.

  In addition, the quick exhaust valve is not arrange | positioned between the suction side air chamber 26 (intake / exhaust port 25a) of each air cylinder part 27 and 28, and the corresponding switching valve 4 and 5. FIG. When the quick exhaust valve is attached to the suction side, the same effect as when the quick exhaust valve is attached to the discharge side is obtained, but the effect is not as great as that of the discharge side. Therefore, the quick exhaust valve on the suction side is not installed as an embodiment from the viewpoint of cost.

[Configuration of control unit]
The control unit 6 switches the switching valves 4 and 5 based on the detection signals of the first detection unit 29 and the second detection unit 31 (see FIG. 2), so that the first air cylinder unit 27 of the bellows pump 1 and Each drive of the 2nd air cylinder part 28 is controlled.
FIG. 5 is a block diagram illustrating an internal configuration of the control unit 6. The control unit 6 includes first and second calculation units 6a and 6b, first and second determination units 6c and 6d, and a drive control unit 6e.

  Based on the detection signals of the pair of proximity sensors 29A and 29B, the first calculation unit 6a performs the first extension time from the most contracted state to the most extended state and the most extended state to the most contracted state in the first bellows 13. The first contraction time is calculated. Specifically, the first calculator 6a calculates the elapsed time from the detection end time of the proximity sensor 29A to the detection time of the proximity sensor 29B as the first extension time. The first calculation unit 6a calculates the elapsed time from the detection end time of the proximity sensor 29B to the detection time of the proximity sensor 29A as the first contraction time.

  Based on the detection signals of the pair of proximity sensors 31A and 31B, the second calculation unit 6b performs the second extension time from the most contracted state to the most extended state and the most extended state to the most contracted state in the second bellows 14. The second contraction time is calculated. Specifically, the second calculation unit 6b calculates the elapsed time from the detection end time of the proximity sensor 31A to the detection time of the proximity sensor 31B as the second extension time. The second calculator 6b calculates the elapsed time from the detection end time of the proximity sensor 31B to the detection time of the proximity sensor 31A as the second contraction time.

Based on the calculated first extension time and first contraction time, the first determination unit 6c starts the contraction operation of the first bellows 13 in the most extended state, and the first bellows 13 is moved by the contraction operation. The first time difference until the time when the second bellows 14 in the most extended state starts the contraction operation before reaching the most contracted state is determined.
The 1st determination part 6c of this embodiment determines a 1st time difference using the following formula | equation, for example.
First time difference = (first extension time + first contraction time) / 2

Based on the calculated second extension time and second contraction time, the second determining unit 6d starts the contraction operation of the second bellows 14 in the most extended state, and the second bellows 14 is moved by the contraction operation. A second time difference is determined until the time when the first bellows 13 in the most extended state starts the contraction operation before reaching the most contracted state.
For example, the second determination unit 6d of the present embodiment determines the second time difference using the following equation.
Second time difference = (second extension time + second contraction time) / 2

  The drive control unit 6e controls the drive of the first and second drive devices based on the determined first and second time differences. Specifically, the drive control unit 6e starts the contraction operation of the second bellows 14 in the maximum extension state when the first time difference elapses from the time when the first bellows 13 in the maximum extension state starts the contraction operation. At the time when the second time difference elapses from the time when the second bellows 14 in the most extended state starts the contraction operation, the first and second first bellows 13 are started to contract in the maximum extension state. 2 Drive control of the air cylinder parts 27 and 28 is performed.

The bellows pump device shown in FIG. 1 further includes a power switch 8, a start switch 9, and a stop switch 10.
The power switch 8 outputs an operation command for turning on / off the energization of the bellows pump 1, and the operation command is input to the control unit 6. The start switch 9 outputs an operation command for driving the bellows pump 1, and the operation command is input to the control unit 6. The stop switch 10 outputs an operation command for setting the first bellows 13 and the second bellows 14 in a standby state in which both are in the most contracted state.

[Drive control of bellows pump]
FIG. 6 is a time chart showing an example of drive control of the bellows pump 1 performed by the control unit 6. When the power switch 8 is off, the first and second switching valves 4 and 5 (see FIG. 1) are held in the neutral position. Therefore, when the power switch 8 is off, the air chambers 21 and 26 of the first and second air cylinder portions 27 and 28 of the bellows pump 1 are in communication with the atmosphere. The first bellows 13 and the second bellows 14 are held at a position slightly extended from the standby state so as to be in a balanced state.

  When starting to drive the bellows pump 1, the operator turns on the power switch 8 and then turns on the stop switch 10 to move the first bellows 13 and the second bellows 14 to the standby state. Specifically, the drive control unit 6e excites the solenoid 4a of the first switching valve 4 and the solenoid 5a of the second switching valve 5, and simultaneously contracts the first bellows 13 and the second bellows 14 to the most contracted state. As a result, the first bellows 13 and the second bellows 14 are held in a standby state. In this standby state, the proximity sensor 29A. 31A will be in the ON state which detected the to-be-detected plates 30 and 32, respectively.

Next, when the start switch 9 is turned on by the operator, the drive control unit 6e first includes the first extension time and the first contraction time of the first bellows 13, the second extension time of the second bellows 14, and Control for calculating the second contraction time is executed.
Specifically, the drive control unit 6e demagnetizes the solenoid 4a of the first switching valve 4 and excites the solenoid 4b to extend the first bellows 13 from the most contracted state (standby state) to the most extended state. At the same time, the drive controller 6e demagnetizes the solenoid 5a of the second switching valve 5 and excites the solenoid 5b, so that the second bellows 14 extends from the most contracted state (standby state) to the most extended state.

When the first bellows 13 extends from the most contracted state to the most extended state, the first calculating unit 6a starts from the time (t1) when the proximity sensor 29A is turned off to the time (t2) when the proximity sensor 29B is turned on. And the first extension time (t2-t1) of the first bellows 13 is calculated.
Similarly, when the second bellows 14 extends from the most contracted state to the most extended state, the second calculating unit 6b starts from when the proximity sensor 31A is turned off (t1) to when the proximity sensor 31B is turned on ( The time until t2) is counted, and the second extension time (t2-t1) of the second bellows 14 is calculated.

Next, after a predetermined time (t3-t2) has elapsed, the drive control unit 6e demagnetizes the solenoid 4b of the first switching valve 4 and excites the solenoid 4a, and only the first bellows 13 is contracted from the most extended state to the most contracted state. Shrink to
At that time, the first calculation unit 6a counts the time from the time (t3) when the proximity sensor 29B is turned off to the time (t4) when the proximity sensor 29A is turned on, and the first contraction of the first bellows 13 is performed. Time (t4-t3) is calculated.

Then, the first determination unit 6c determines the first time difference based on the calculated first extension time and first contraction time. In this embodiment, the 1st determination part 6c calculates a 1st time difference using the following formula | equation.
First time difference = (first extension time + first contraction time) / 2 = ((t2−t1) + (t4−t3)) / 2

Next, the drive control unit 6e demagnetizes the solenoid 5b of the second switching valve 5 and excites the solenoid 5a at the same time (t4) when the first bellows 13 contracts to the most contracted state. Shrink from the most extended state to the most contracted state.
At that time, the second calculation unit 6b counts the time from the time (t4) when the proximity sensor 31B is turned off to the time (t6) when the proximity sensor 31A is turned on, and the second contraction of the second bellows 14 is performed. Time (t6-t4) is calculated.

Then, the second determination unit 6d determines the second time difference based on the calculated second extension time and second contraction time. In this embodiment, the 2nd determination part 6d calculates a 2nd time difference using the following formula | equation.
Second time difference = (second extension time + second contraction time) / 2 = ((t2-t1) + (t6-t4)) / 2

In the following, each time the first bellows 13 reciprocates once by the first calculation unit 6a and the first determination unit 6c, the first extension time and the first contraction time are calculated as described above. A first time difference is determined based on the first extension time and the first contraction time.
Similarly, each time the second bellows 14 reciprocates once by the second calculation unit 6b and the second determination unit 6d, the second extension time and the second contraction time are calculated as described above, and the calculated second A second time difference is determined based on the extension time and the second contraction time.

On the other hand, the drive controller 6e starts driving the first bellows 13 before the second bellows 14 is in the most contracted state. Specifically, the drive control unit 6e demagnetizes the solenoid 4a of the first switching valve 4 and excites the solenoid 4b before the second bellows 14 reaches the most contracted state (t5). Thereby, the 1st bellows 13 starts extension operation from the most contracted state.
The second bellows 14 is in the most contracted state after a predetermined time (t6-t5) after the first bellows 13 starts to extend, and the proximity sensor 31B switches from off to on, but the drive control unit 6e The second bellows 14 is held in the most contracted state for a while.

Thereafter, when the proximity sensor 29B is switched from OFF to ON at the time when the first bellows 13 reaches the maximum extension state (t7), the drive control unit 6e performs the first switching after a predetermined time (t8-t7) has elapsed. The solenoid 4b of the valve 4 is demagnetized and the solenoid 4a is excited. Thereby, the 1st bellows 13 starts contraction operation from the maximum extension state.
The drive control unit 6e starts counting the first time difference determined above from the time point (t8) when the solenoid 4a is excited.

When a predetermined time (t9-t8) elapses after the first bellows 13 starts to contract, the drive control unit 6e demagnetizes the solenoid 5a of the second switching valve 5 and excites the solenoid 5b. Thereby, while the 1st bellows 13 is carrying out contraction operation, the 2nd bellows 14 is extended from the maximum contraction state to the maximum extension state.
At that time, when the second bellows 14 reaches the maximum extension state (t10), the proximity sensor 31B switches from off to on, but the drive control unit 6e holds the second bellows 14 in the maximum extension state. Keep it.

Next, when the first time difference (t11−t8) has elapsed, the drive control unit 6e demagnetizes the solenoid 5b of the second switching valve 5 and excites the solenoid 5a. Thereby, the 2nd bellows 14 starts contraction operation from the maximum extension state before the 1st bellows 13 will be in the maximum contraction state (refer to Drawing 8).
Moreover, the drive control part 6e starts the count of the 2nd time difference determined above from the time (t11) which excited the solenoid 5a.

After the second bellows 14 starts contracting operation, when the proximity sensor 29A is switched from OFF to ON at the time (t12) when the first bellows 13 is in the most contracted state, the drive control unit 6e The solenoid 4a of the switching valve 4 is demagnetized and the solenoid 4b is excited. As a result, while the second bellows 14 is contracting, the first bellows 13 extends from the most contracted state to the most extended state.
At that time, when the first bellows 13 reaches the maximum extension state (t13), the proximity sensor 29B switches from off to on, but the drive control unit 6e holds the first bellows 13 in the maximum extension state. Keep it.

Next, when the second time difference (t14−t11) has elapsed, the drive control unit 6e demagnetizes the solenoid 4b of the first switching valve 4 and excites the solenoid 4a. Thereby, before the 2nd bellows 14 will be in the most contracted state, the 1st bellows 13 starts contraction operation from the maximum extension state (refer to Drawing 7).
Moreover, the drive control part 6e starts the count of the 1st time difference determined immediately before from the time (t14) which excited the solenoid 4a. The first time difference determined immediately before this time is determined based on the first extension time (t7-t5) and the first contraction time (t12-t8) calculated by one reciprocating motion immediately before the first bellows 13. Is.

After the first bellows 13 starts the contraction operation, when the proximity sensor 31A is switched from OFF to ON at the time (t15) when the second bellows 14 is in the most contracted state, the drive control unit 6e The solenoid 5a of the switching valve 5 is demagnetized and the solenoid 5b is excited. Thereby, while the 1st bellows 13 is carrying out contraction operation, the 2nd bellows 14 is extended from the maximum contraction state to the maximum extension state.
At that time, when the second bellows 14 reaches the maximum extension state (t16), the proximity sensor 31B switches from OFF to ON, but the drive control unit 6e holds the second bellows 14 in the maximum extension state. Keep it.

Next, when the first time difference (t17−t14) determined immediately before has elapsed, the drive control unit 6e demagnetizes the solenoid 5b of the second switching valve 5 and excites the solenoid 5a. Thereby, the 2nd bellows 14 starts contraction operation from the maximum extension state before the 1st bellows 13 will be in the maximum contraction state.
Moreover, the drive control part 6e starts the count of the 2nd time difference determined immediately before from the time (t17) when the solenoid 5a was excited. The second time difference determined immediately before this time was determined based on the second extension time (t10-t9) and the second contraction time (t15-t11) calculated by one reciprocating motion immediately before the second bellows 14. Is.

After the second bellows 14 starts contracting operation, when the proximity sensor 29A is switched from OFF to ON at the time (t18) when the first bellows 13 is in the most contracted state, the drive control unit 6e The solenoid 4a of the switching valve 4 is demagnetized and the solenoid 4b is excited. As a result, while the second bellows 14 is contracting, the first bellows 13 extends from the most contracted state to the most extended state.
At that time, when the first bellows 13 reaches the maximum extension state (t19), the proximity sensor 29B switches from off to on, but the drive control unit 6e holds the first bellows 13 in the maximum extension state. Keep it.

  Next, when the second time difference (t20−t17) determined immediately before has elapsed, the drive control unit 6e demagnetizes the solenoid 4b of the first switching valve 4 and excites the solenoid 4a. Thereby, the 1st bellows 13 starts contraction operation from the maximum extension state before the 2nd bellows 14 will be in the maximum contraction state.

Thereafter, as described above, the drive control unit 6e moves the first bellows 13 from the most extended state before the second bellows 14 is in the most contracted state based on the first and second time differences determined immediately before. The bellows pump 1 is driven and controlled so that the second bellows 14 is contracted from the maximum extension state before the first bellows 13 is in the maximum contraction state.
Therefore, even if the first and second contraction times (discharge time) and the first and second extension times (suction time) vary depending on the discharge load of the transfer fluid, etc., the bellows follows the variation and is optimally timed. The pump 1 can be driven and controlled.

  In this embodiment, the first and second time differences determined immediately before are used. However, if there is no change in the discharge time or the suction time, the first and first time differences determined immediately after the start of operation are used. The bellows pump 1 may be driven and controlled using the second time difference. In this case, the extension operation and the contraction operation of the first and second bellows 13 and 14 may be switched at predetermined intervals using a timer or the like without using the proximity sensors 29A, 29B, 31A, and 31B. good.

  When stopping the driving of the bellows pump 1, first, the operator turns on the stop switch 10. Upon receiving this operation signal, the drive control unit 6e moves the first bellows 13 and the second bellows 14 to the standby state. At that time, when either one of the first bellows 13 and the second bellows 14 is performing the extending operation, the drive control unit 6e stops the extending operation and immediately starts the contracting operation. And if the 1st bellows 13 and the 2nd bellows 14 will be in a stand-by state, the operator will turn off power switch 8.

[Configuration of electro-pneumatic regulator]
1 and 2, the first electropneumatic regulator 51 is disposed between the mechanical regulator 3 and the first switching valve 4. In addition, the second electropneumatic regulator 52 is disposed between the mechanical regulator 3 and the second switching valve 5. Each of the electropneumatic regulators 51 and 52 has a function of steplessly adjusting the air pressure output from the output port (not shown) based on a preset pressure preset from the outside.

The first electropneumatic regulator 51 of the present embodiment uses the compressed air pressure supplied to the discharge-side air chamber 21 of the first air cylinder portion 27 during the contraction of the first bellows 13 to the contraction characteristics of the first bellows 13. The air pressure is controlled so as to increase correspondingly.
The second electropneumatic regulator 52 converts the air pressure of the pressurized air supplied to the discharge-side air chamber 21 of the second air cylinder portion 28 into the contraction characteristic of the second bellows 14 during the contraction operation of the second bellows 14. The air pressure is controlled to increase correspondingly.

[Control of electro-pneumatic regulator]
FIG. 9 is a graph showing an example of air pressure control of the first and second electropneumatic regulators 51 and 52. In FIG. 9, during the extension time T1 during which the first bellows 13 is extended (during the extension operation), the first electropneumatic regulator 51 performs control so that the air pressure of the pressurized air always becomes a constant air pressure c. During the contraction time T2 during which the first bellows 13 is contracted (during contraction operation), the first electropneumatic regulator 51 uses the following formula to calculate the air pressure of the pressurized air every unit time (for example, 10 ms). Control.
P = at + b
Where P is the air pressure of the pressurized air output from the output port, a is the pressure increase coefficient, t is the elapsed time of contraction of the first bellows 13, and b is the initial air pressure. In this embodiment, the pressure increase coefficient a indicates the contraction characteristic of the first bellows 13, and the initial air pressure b is set to a value larger than the air pressure c.

  Similarly, during the extension time T3 during which the second bellows 14 is extended (during the extension operation), the second electropneumatic regulator 52 performs control so that the air pressure of the pressurized air always becomes a constant air pressure c. During the contraction time T4 during which the second bellows 14 is contracting (during contraction operation), the second electropneumatic regulator 52 controls the air pressure of the pressurized air using the above formula every unit time (for example, 10 ms). To do. In this case, however, t is the contraction elapsed time of the second bellows 14, and the pressure increase coefficient a indicates the contraction characteristic of the second bellows 14.

  In this embodiment, the pressure increase coefficient a and the initial air pressures b and c used when the first and second electropneumatic regulators 51 and 52 respectively control are set to the same value. It may be set to a different value depending on the empty regulator.

FIG. 10 is a graph showing the discharge pressure of the transfer fluid discharged from the bellows pump 1. As shown in FIG. 10, the first and second electropneumatic regulators 51 and 52 control the air pressure of the pressurized air as described above, so that the bellows 13 and 14 are contracted independently (in the figure). The portion surrounded by the broken line) can reduce the drop in the discharge pressure of the transfer fluid discharged from the bellows pump 1.
Further, as described above, when the drive control unit 6e controls the bellows pump 1 based on the first and second time differences, the switching timing from the contraction (discharge) to the extension (suction) of one bellows (see FIG. In the portion surrounded by the solid line), the other bellows is already contracted to discharge the transfer fluid, so that it is possible to reduce the drop in the discharge pressure at the switching timing.
Therefore, the pulsation on the discharge side of the bellows pump 1 can be effectively reduced by combining the control of the first and second electropneumatic regulators 51 and 52 and the control of the drive control unit 6e.

  As described above, according to the bellows pump device of the present embodiment, when the bellows 13 (14) is contracted, the air pressure of the pressurized air supplied to the discharge-side air chamber 21 is increased by the electropneumatic regulator 51 (52). Since it rises corresponding to the shrinkage characteristic of (14), the air pressure of the pressurized air in the discharge side air chamber 21 can be raised as the bellows 13 (14) shrinks. Thereby, it can reduce that the discharge pressure of a transfer fluid falls while the bellows 13 (14) is shrink | contracting.

  In addition, since the electropneumatic regulator 51 (52) controls the air pressure using the above-mentioned formula every unit time, it is effective that the discharge pressure of the transfer fluid drops while the bellows 13 (14) is contracted. Can be reduced.

  In addition, the first bellows 13 and the second bellows 14 can be expanded and contracted independently of each other, and in the control unit 6, the second bellows 14 is contracted from the maximum extension state before the first bellows 13 is in the maximum contraction state, Since the drive control is performed so that the first bellows 13 is contracted from the most extended state before the second bellows 14 is in the most contracted state, the following operational effects can be obtained. That is, at the switching timing from contraction (discharge) to expansion (suction) of one bellows, the other bellows is already contracted and discharges the transfer fluid, so that the discharge pressure greatly decreases at the switching timing. can do. As a result, the pulsation on the discharge side of the bellows pump 1 can be reduced.

  In addition, the bellows pump device according to the present embodiment does not need to secure a space for installing other members (accumulators) other than the bellows pump, as compared with the bellows pump having an accumulator attached to the discharge side thereof. A significant increase can be suppressed. Furthermore, the bellows pump device according to the present embodiment discharges a transfer fluid using a pair of bellows 13 and 14 in the same manner as a bellows pump in which a pair of bellows is connected by a conventional tie rod, so that the amount of fluid discharged is reduced. I don't have to.

  In addition, the control unit 6 uses the first time difference determined based on the first extension time and the first contraction time of the first bellows 13 to be in the maximum extension state before the first bellows 13 is in the maximum contraction state. The second bellows 14 is contracted, and the second bellows 14 is stretched most before the second bellows 14 is in the most contracted state by using the second time difference determined based on the second extension time and the second contraction time of the second bellows 14. The drive control can be performed so that the first bellows 13 in the state is contracted. Accordingly, the second bellows can be reliably contracted before the first bellows is in the most contracted state, and the first bellows can be reliably contracted before the second bellows is in the most contracted state.

  Further, immediately after the start of the operation of the bellows pump 1, the control unit 6 calculates the extension time and the contraction time of the first and second bellows 13 and 14 in advance and controls the drive. Even when the contraction time is unknown, the second bellows 14 (first bellows 13) can be reliably contracted before the first bellows 13 (second bellows 14) reaches the maximum contraction state.

  Moreover, since the control part 6 controls drive based on the 1st and 2nd time difference determined immediately before, the 1st extension time of the 1st bellows 13 and the 1st contraction time (the 2nd extension time of the 2nd bellows 14) Even if there is a change in the second contraction time), the second bellows 14 (the first bellows 13) is surely followed by the change before the first bellows 13 (the second bellows 14) is in the most contracted state. Can be shrunk.

[Modification]
FIG. 11 is a schematic configuration diagram showing a modification of the bellows pump device in the embodiment. The bellows pump device in this modification is not shown in the figure, but a pair of left and right bellows are integrally connected by tie rods as in the prior art, and each air cylinder portion 27, 28 has a discharge side air chamber 21. Only the intake / exhaust port 22 is formed.
Accordingly, when pressurized air is supplied to one discharge-side air chamber 21, the bellows contracts and the transfer fluid is discharged, and at the same time, the other bellows is forcibly extended and the transfer fluid is sucked from the suction passage. . When pressurized air is supplied to the other discharge-side air chamber 21, the other bellows contracts to discharge the transfer fluid, and at the same time, the one bellows is forcibly extended to suck the transfer fluid. .

Each intake / exhaust port 22 is connected to the air supply device 2 via a single switching valve 7, a single electropneumatic regulator 53, and a mechanical regulator 3.
The switching valve 7 excites or demagnetizes a pair of solenoids (not shown) to supply pressurized air to one of the discharge side air chambers 21 of both air cylinder portions 27 and 28 and discharge the pressurized air from the other. Switch the supply and discharge of pressurized air.

  The electropneumatic regulator 53 controls the air pressure so as to increase the air pressure of the pressurized air supplied to the corresponding discharge-side air chamber 21 in accordance with the contraction characteristics of the bellows to contract during the contraction operation of each bellows. . Details thereof are the same as those in the above embodiment, and a description thereof will be omitted.

The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention described in the claims. For example, the present invention can be applied to other bellows pumps such as a bellows pump configured by replacing one of a pair of bellows with an accumulator, in addition to the above-described embodiments and modifications.
Moreover, although the electropneumatic regulators 51 to 53 are disposed on the upstream side of the switching valves 4, 5, and 7, they may be disposed on the downstream side of the switching valves 4, 5, and 7. However, in this case, since the impact pressure generated when the switching valves 4, 5, and 7 are switched acts on the primary side of the electropneumatic regulators 51 to 53, failure of the electropneumatic regulators 51 to 53 is prevented. From the viewpoint, it is preferable to dispose the electropneumatic regulators 51 to 53 upstream of the switching valves 4, 5 and 7.

  Moreover, although the 1st and 2nd detection means 29 and 31 in the said embodiment are comprised by the proximity sensor, you may be comprised by other detection means, such as a limit switch. Moreover, although the 1st and 2nd detection means 29 and 31 are detecting the maximum expansion state and the maximum expansion-contraction state of the 1st and 2nd bellows 13 and 14, you may make it detect another expansion-contraction state. good. Further, the first and second driving devices 27 and 28 in the present embodiment are driven by pressurized air, but may be driven by other fluids, motors, or the like.

6 Control part 13 1st bellows (bellows)
14 Second bellows (bellows)
21 Discharge side air chamber (air chamber)
27 1st air cylinder part (1st drive device)
28 Second Air Cylinder (Second Drive Device)
29 1st detection means 31 2nd detection means 51 1st electropneumatic regulator (electropneumatic regulator)
52 Second electropneumatic regulator (electropneumatic regulator)
53 Electropneumatic regulator

Claims (3)

By supplying pressurized air to the sealed air chamber, the bellows disposed in the air chamber is contracted to discharge the transfer fluid, and the compressed air is discharged from the air chamber to extend the bellows. A bellows pump device that operates and sucks a transfer fluid,
The air pressure of the pressurized air supplied to the air chamber corresponds to the contraction characteristics of the bellows in order to reduce the drop in the discharge pressure of the transfer fluid while the bellows contracts during the contraction operation of the bellows. A bellows pump device comprising an electropneumatic regulator for controlling the air pressure so that the air pressure is raised. The bellows pump device according to claim 1, wherein the electropneumatic regulator controls the air pressure using the following formula every unit time.
P = at + b
Where P is the air pressure, a is the pressure increase coefficient, t is the elapsed time of contraction of the bellows, and b is the initial air pressure. The bellows is composed of a first bellows and a second bellows that can be expanded and contracted independently of each other,
A first driving device that continuously expands and contracts the first bellows between the most extended state and the most contracted state;
A second driving device that continuously expands and contracts the second bellows between the most extended state and the most contracted state;
First detection means for detecting the expansion and contraction state of the first bellows;
Second detection means for detecting the expansion and contraction state of the second bellows;
Based on the detection signals of the first and second detection means, the second bellows is contracted from the most extended state before the first bellows is in the most contracted state, and the second bellows is in the most contracted state. The bellows pump device according to claim 1, further comprising a control unit that drives and controls the first and second drive devices so that the first bellows is contracted from the most extended state before the first bellows.

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