JP6371207B2 - 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.

When one of the pair of bellows contracts, the transfer fluid inside the bellows is discharged, and at the same time, the other bellows expands to suck the transfer fluid into the inside. Further, the other bellows contracts to discharge the transfer fluid inside thereof, and at the same time, the one bellows extends to suck the transfer fluid into the inside.
The bellows pump is connected to a mechanical regulator for adjusting the pressurized air supplied to the air chamber in each pump case to an appropriate air pressure.

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. 15, 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.

Accordingly, the present applicant has proposed a bellows pump device using an electropneumatic regulator instead of a mechanical regulator (Japanese Patent Application No. 2014-162125, hereinafter referred to as “prior application invention”).
In the invention of the prior application, the bellows contracts by adjusting the air pressure of the pressurized air supplied to the air chamber so as to increase corresponding to the contraction characteristics of the bellows by the electropneumatic regulator during the contraction operation of the bellows. Accordingly, the air pressure of the pressurized air in the air chamber can be increased, and the drop in the discharge pressure of the transfer fluid while the bellows is contracted can be reduced.

However, in the bellows pump device of the invention of the prior application, the electropneumatic regulator outputs the pressurized air in an output cycle in which the air pressure of the pressurized air is always set to a constant pressure increase coefficient. There is a fear.
That is, when the high-temperature transfer fluid and the low-temperature transfer fluid are supplied in this order by the bellows pump device of the invention of the prior application, for example, when the supply of the high-temperature transfer fluid is switched to the supply of the low-temperature transfer fluid, the bellows A bellows may become hard because the temperature of the transfer fluid sucked in becomes low. When such a change occurs, the bellows becomes difficult to contract. However, the electropneumatic regulator outputs pressurized air with an output cycle in which the air pressure is a constant pressure increase coefficient regardless of the hardness of the bellows. The discharge pressure decreases, and the discharge pressure cannot be made constant.

If it becomes impossible to make the discharge pressure of the transfer fluid constant, the pulsation of the bellows pump device will increase, and foreign matter will flow out from the filter installed in the middle of the transfer fluid supply pipe, or will be ejected from the tip of the nozzle The pattern on the wafer may collapse due to the pulsation of the transfer fluid, which may adversely affect the semiconductor manufacturing process.
The present invention has been made in view of such circumstances, and provides a bellows pump device capable of suppressing a change in discharge pressure of a transfer fluid even if a temperature change occurs in the transfer fluid during a bellows contraction operation. The purpose is to do.

  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. Correspondingly, the electropneumatic regulator that adjusts to increase, the temperature detection unit that detects the temperature of the transfer fluid, and the lower the detection value of the temperature detection unit, the larger the pressure increase coefficient when increasing the air pressure And a control unit for controlling the electropneumatic regulator.

  According to the bellows pump device configured as described above, the control unit reduces the air pressure of the pressurized air supplied to the air chamber when the bellows contracts, as the temperature of the transfer fluid detected by the temperature detection unit decreases. The electropneumatic regulator is controlled so that the pressure increase coefficient becomes large. As a result, for example, even if the temperature of the transfer fluid decreases and the bellows becomes hard, the pressure increase coefficient of the air pressure of the pressurized air supplied to the air chamber increases, so that the air pressure before the temperature decrease of the transfer fluid The bellows can be shrunk even at high air pressure. Therefore, even if the hardness of the bellows changes due to the temperature change of the transfer fluid, it is possible to suppress the change in the discharge pressure of the transfer fluid while the bellows contracts.

It is preferable that the control unit sets a pressure increase coefficient of the air pressure based on a detection value of the temperature detection unit so that the maximum value of the air pressure does not exceed an allowable pressure resistance of the bellows.
In this case, even if the pressure increase coefficient of the compressed air supplied to the air chamber increases, the maximum value of the air pressure does not exceed the allowable pressure resistance of the bellows. It can be prevented from being damaged.

Preferably, the control unit has a lookup table in which the pressure increase coefficient is set corresponding to each of a plurality of temperature regions, and controls the electropneumatic regulator based on the lookup table.
In this case, the electropneumatic regulator can be easily controlled based on the lookup table.

  According to the bellows pump device of the present invention, even if a temperature change occurs in the transfer fluid during the bellows contraction operation, a change in the discharge pressure of the transfer fluid can be suppressed.

It is a mimetic diagram showing composition of a fluid feed system provided with a bellows pump device concerning an embodiment of the present invention. It is a schematic block diagram of a bellows pump device. 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 graph which shows an example of adjustment of the air pressure of an electropneumatic regulator. It is an example of the look-up table which a control part has. It is a graph which shows the change of the air pressure of the electropneumatic regulator controlled by a control part corresponding to each of a plurality of temperature fields. It is a graph which shows the relationship between the temperature of a transfer fluid, and the allowable pressure | voltage resistance of a bellows. It is a graph which shows the change of the discharge pressure of the transfer fluid discharged from a bellows pump by control of the electropneumatic regulator which concerns on the comparative example 1. FIG. It is a graph which shows the change of the discharge pressure of the transfer fluid discharged from a bellows pump by control of the electropneumatic regulator which concerns on Example 1. FIG. It is a graph which shows the change of the discharge pressure of the transfer fluid discharged from a bellows pump by control of the electropneumatic regulator which concerns on the comparative example 2. It is a graph which shows the change of the discharge pressure of the transfer fluid discharged from a bellows pump by control of the electropneumatic regulator which concerns on Example 2. FIG. It is a graph which shows the change of the discharge pressure of the transfer fluid discharged from a bellows pump by control of the electropneumatic regulator which concerns on Example 3. FIG. 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.
[System overall configuration]
Drawing 1 is a mimetic diagram showing composition of a fluid feed system provided with a bellows pump device concerning an embodiment of the present invention. The fluid feeding system feeds a certain amount of transport fluid such as a chemical solution or a solvent in a semiconductor manufacturing apparatus, for example. This fluid feeding system is composed of a tank 70 for storing a transfer fluid, a circulation path 71 for feeding the transfer fluid stored in the tank 70 to the outside and returning it to the tank 70, and a branch from the middle of the circulation path 71 for transfer. A plurality of supply paths 72 for supplying fluid to a wafer (not shown) and a bellows pump device 1 for supplying a transfer fluid from a tank 70 are provided.

A filter 73 is provided in the circulation path 71 on the downstream side of the bellows pump device 1. The circulation path 71 is provided with an opening / closing valve 74 for opening and closing the circulation path 71 downstream of the branch point with the supply path 72.
The supply path 72 is provided with a plurality of nozzles 75 that eject the transfer fluid.

The fluid supply system further includes a temperature sensor 76 that detects the temperature of the transfer fluid in the tank 70 and a plurality of (two in the illustrated example) heaters 77 arranged in the middle of the circulation path 71.
The heater 77 heats the transfer fluid in the circulation path 71 based on the temperature of the transfer fluid detected by the temperature sensor 76. Thereby, the temperature of the transfer fluid ejected from the nozzle 75 through the supply path 72 from the circulation path 71 can be maintained at an appropriate temperature.
The temperature sensor 76 is provided in the tank 70, but may be provided in the middle of the circulation path 71 or in the middle of the supply path 72.

[Configuration of bellows pump device]
FIG. 2 is a schematic configuration diagram of the bellows pump device 1. The bellows pump device 1 of this embodiment includes a bellows pump 10, an air supply device 2 such as an air compressor that supplies pressurized air (working fluid) to the bellows pump 10, and a machine that adjusts the air pressure of the pressurized air. Regulator 3 and two first and second electropneumatic regulators 51 and 52, two first and second electromagnetic valves 4 and 5, a control unit 6 that controls driving of the bellows pump 10, and a transfer fluid The temperature detection part 7 which detects the temperature of this is provided.

FIG. 3 is a cross-sectional view of the bellows pump according to the embodiment of the present invention.
The bellows pump 10 of this 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 electromagnetic valve 4 (5), the electropneumatic regulator 51 (52), and the mechanical regulator 3. (See FIG. 2). Thus, 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 electromagnetic 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 electromagnetic valve 4 (5), the electropneumatic regulator 51 (52), and a mechanical regulator. 3 is connected to the air supply device 2 (see FIG. 2). 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 electromagnetic 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.

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. 3 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. 3 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. 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 the tank 70 of the transfer fluid, and the discharge port is connected to the transfer destination of the transfer fluid. 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 allows the transfer fluid to flow out from the inside of the bellows 13 and 14 toward the discharge passage 35. Then, when the bellows 13 and 14 are extended, the valve is closed to prevent the backflow of the transfer fluid from the discharge passage 35 toward the inside of the bellows 13 and 14.

[Bellows pump operation]
Next, operation | movement of the bellows pump 10 of this embodiment is demonstrated with reference to FIG.4 and FIG.5. In FIGS. 4 and 5, the configurations of the first and second bellows 13 and 14 are shown in a simplified manner.
As shown in FIG. 4, 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. 5, 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 figure. 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 solenoid valve]
In FIG. 2, the first solenoid valve 4 is configured to supply / discharge pressurized air to / from one of the discharge-side air chamber 21 and the suction-side air chamber 26 of the first air cylinder portion 27 and the other air chamber. This switches the supply and discharge of pressurized air to and from. The 1st electromagnetic valve 4 consists of a 3 position electromagnetic switching valve which has a pair of solenoid 4a, 4b, for example. Each solenoid 4a, 4b is excited by receiving a command signal from the control unit 6. In addition, although the 1st electromagnetic 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 solenoid valve 4 is held in the neutral position when both solenoids 4a and 4b are demagnetized, and the discharge side air chamber 21 (intake / exhaust port 22) of the first air cylinder portion 27 and the suction from the air supply device 2. 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 electromagnetic 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 solenoid 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 solenoid valve 5 supplies and discharges pressurized air to one of the discharge side air chamber 21 and the suction side air chamber 26 of the second air cylinder portion 28 and pressurizes the other air chamber. This switches between air supply and exhaust. The second electromagnetic valve 5 is composed of, for example, a three-position electromagnetic switching valve having a pair of solenoids 5a and 5b. Each solenoid 5a, 5b is excited by receiving a command signal from the control unit 6. In addition, although the 2nd electromagnetic valve 5 of this embodiment consists of a 3 position electromagnetic switching valve, a 2 position electromagnetic switching valve which does not have a neutral position may be sufficient.

  The second solenoid 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 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 electromagnetic 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.

  Further, when the solenoid 5b is excited, the second solenoid 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. 2, 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 electromagnetic valve 4. Has been placed. The first quick exhaust valve 61 has an exhaust port 61a that discharges pressurized air, allows the flow of pressurized air from the first electromagnetic 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 electromagnetic 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 and exhaust port 22) of the second air cylinder portion 28 and the second electromagnetic 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 electromagnetic 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 electromagnetic 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 solenoid valves 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 electromagnetic valves 4 and 5 based on the detection signals of the first detection unit 29 and the second detection unit 31 (see FIG. 3), so that the first air cylinder unit 27 of the bellows pump 10 and Each drive of the 2nd air cylinder part 28 is controlled.

  Specifically, the control unit 6 contracts the second bellows 14 from the maximum extension state before the first bellows 13 reaches the maximum contraction state based on the detection signals of the first detection unit 29 and the second detection unit 31. At the same time, the first and second air cylinder portions 27 and 28 are driven and controlled so that the first bellows 13 is contracted from the maximum extension state before the second bellows 14 is in the maximum contraction state.

  As a result, 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 of the transfer fluid is large at the switch timing. Depressing can be reduced. As a result, the pulsation on the discharge side of the bellows pump 1 can be reduced.

  In addition, although the control part 6 of this embodiment is contracting the other bellows 14 (13) from the most extended state before one bellows 13 (14) will be in the most contracted state, one bellows 13 (14 ) May be controlled such that the other bellows 14 (13) is contracted from the most extended state when the most contracted state is reached. However, from the viewpoint of reducing the pulsation on the discharge side of the bellows pump 1, it is preferable to perform control as in this embodiment.

[Configuration of electro-pneumatic regulator]
In FIG. 2, the first electropneumatic regulator 51 is disposed between the mechanical regulator 3 and the first electromagnetic valve 4. The first electropneumatic regulator 51 corresponds to the air pressure of the pressurized air supplied to the discharge side air chamber 21 of the first air cylinder portion 27 during the contraction operation of the first bellows 13 according to the contraction characteristics of the first bellows 13. Adjust to raise.

  The second electropneumatic regulator 52 is disposed between the mechanical regulator 3 and the second electromagnetic valve 5. The second electropneumatic regulator 52 corresponds to the air pressure of the pressurized air supplied to the discharge side air chamber 21 of the second air cylinder portion 28 in accordance with the contraction characteristics of the second bellows 14 during the contraction operation of the second bellows 14. Adjust to raise.

FIG. 6 is a graph showing an example of adjusting the air pressure of the first and second electropneumatic regulators 51 and 52. In FIG. 6, during the extension time T1 during which the first bellows 13 is extended (during extension operation), the first electropneumatic regulator 51 adjusts so that the air pressure of the pressurized air is always a constant air pressure c. The air pressure c is instructed from the control unit 6. During the contraction time T2 during which the first bellows 13 is contracted (during contraction operation), the first electropneumatic regulator 51 is calculated by the control unit 6 using the following formula every unit time (for example, 10 ms). The air pressure is adjusted in accordance with an instruction from the control unit 6 so as to be the air pressure of the pressurized air.
P = aX + b
Here, P is the air pressure of the pressurized air output from the output port, a is the pressure increase coefficient, X is the expansion / contraction position 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. Further, the expansion / contraction position X is, for example, the maximum stretched state of the first bellows 13 as X ₀ (= ₀ mm) as shown in FIG. 4, and the maximum contracted state of the first bellows 13 as X _max as shown in FIG. It is set as a displacement from X _0.

  Similarly, during the extension time T3 during which the second bellows 14 is extended (during the extension operation), the second electropneumatic regulator 52 adjusts so that the air pressure of the pressurized air always becomes a constant air pressure c. The air pressure c is instructed from the control unit 6. Then, during the contraction time T4 during which the second bellows 14 is contracted (during contraction operation), the second electropneumatic regulator 52 is controlled by the control unit 6 using the above formula every unit time (for example, 10 ms). The air pressure is adjusted according to an instruction from the control unit 6 so that the air pressure of the compressed air becomes the air pressure. However, in this case, X is the expansion / contraction position of the second bellows 14, and the pressure increase coefficient a indicates the contraction characteristic of the second bellows 14.

As described above, by setting X in the above formula as the expansion / contraction position of the bellows 13 (14), for example, even when the discharge fluid resistance increases and the discharge time increases, the pressure increase in a look-up table to be described later The numerical value of the coefficient a can be used as a fixed value.
In addition, the current expansion / contraction position of the bellows 13 (14) can be calculated based on, for example, a time difference required from the most expanded state to the most contracted state of the bellows 13 (14) acquired in advance by position measurement. Of course, the current expansion / contraction position of the bellows 13 (14) can also be detected by a displacement sensor or the like.

  In this embodiment, the pressure increase coefficient a and the initial air pressures b and c used when calculating the air pressure adjusted by the electropneumatic regulators 51 and 52 in the control unit 6 are both set to the same value. The value may be set differently depending on each electropneumatic regulator.

[Control of electro-pneumatic regulator]
In FIG. 2, the control unit 6 controls the electropneumatic regulators 51 and 52 based on the temperature of the transfer fluid detected by the temperature detection unit 7. In the present embodiment, a temperature sensor 76 (see FIG. 1) for adjusting the temperature of the transfer fluid in the circulation path 71 is used as the temperature detection unit 7. Therefore, the control unit 6 of this embodiment controls the electropneumatic regulators 51 and 52 based on the detection value of the temperature sensor 76.

  In the present embodiment, the temperature sensor 7 for adjusting the temperature of the transfer fluid in the circulation path 71 is used as the temperature detection unit 7 for controlling the electropneumatic regulators 51 and 52. However, the bellows pump 10 A dedicated temperature sensor for detecting the temperature of the transfer fluid may be provided.

  The control unit 6 of the present embodiment controls the electropneumatic regulators 51 and 52 such that the pressure increase coefficient a when the air pressure of the pressurized air is increased increases as the detection value of the temperature sensor 76 decreases. Specifically, the control unit 6 has a lookup table in which a pressure increase coefficient a is set corresponding to each of a plurality of temperature regions, and the electropneumatic regulators 51 and 52 are controlled based on the lookup table. Thus, the air pressure to be adjusted by each of the electropneumatic regulators 51 and 52 is indicated.

  FIG. 7 is an example of a lookup table 6a that the control unit 6 has. The look-up table 6a of the present embodiment includes a pressure increase coefficient corresponding to each of three types of temperature regions: a low temperature region (10 to 20 ° C.), a medium temperature region (20 to 60 ° C.), and a high temperature region (60 to 80 ° C.). a1, a2 and a3 are shown. The pressure increase coefficients a1 to a3 are all experimentally determined coefficients and are set so as to satisfy the relationship of a1> a2> a3.

  The control unit 6 of the present embodiment controls the electropneumatic regulators 51 and 52 using a look-up table method, but calculates a pressure increase coefficient using an arithmetic expression from the detection value of the temperature sensor 76 and the like. You may make it do. Further, four or more temperature regions may be set.

FIG. 8 is a graph showing changes in air pressure of the electropneumatic regulator 51 (52) controlled by the control unit 6 corresponding to each of a plurality of temperature regions. As shown in FIG. 8, the start air pressures Ps1, Ps2, and Ps3 at the start of contraction of the bellows 13 (14) corresponding to the low temperature region, the intermediate temperature region, and the high temperature region are set to the initial air pressure b that is the same value. Yes.
And as the bellows 13 (14) contracts, the air pressure corresponding to each temperature region increases due to the difference in pressure increase coefficients a1 to a3 (inclination of the increasing straight line), and is higher as the temperature region is lower. Value.
Note that the start air pressures Ps1 to Ps3 corresponding to each temperature region may be set to different values, for example, set to a higher value as the temperature region becomes lower.

  FIG. 9 is a graph showing the relationship between the temperature of the transfer fluid and the allowable pressure resistance of the bellows 13 (14). The “allowable pressure resistance” of the bellows 13 (14) is a pressure difference between the pressure outside the bellows 13 (14) (discharge side air chamber 21) and the pressure inside the bellows 13 (14). (14) is the maximum differential pressure that does not deform or break.

  As can be seen from FIG. 9, the allowable pressure resistance of the bellows 13 (14) decreases as the temperature of the transfer fluid increases. Therefore, in order to protect the bellows 13 (14), the starting air pressures Ps1 to Ps3 (initial air pressure b in the present embodiment) or the pressure increase coefficients a1 to a3 of the air pressure in the lookup table 6a (see FIG. 7) The maximum value of air pressure (gauge pressure not including atmospheric pressure) corresponding to the temperature region is set so as not to exceed the allowable pressure resistance of the bellows 13 (14).

That is, as shown in FIG. 8, the end air pressures Pe1, Pe2, Pe3 at the end of contraction of the bellows 13 (14), which are the maximum values of the air pressure corresponding to the low temperature region, the medium temperature region, and the high temperature region, The starting air pressures Ps1 to Ps3 or the pressure increase coefficients a1 to a3 are set so as not to exceed the allowable pressure resistance of the bellows 13 (14) corresponding to the maximum temperature.
For example, in the case of the high temperature region (60 to 80 ° C.), the end air pressure Pe3 does not exceed the allowable pressure resistance (about 0.6 MPa in FIG. 9) of the bellows 13 (14) corresponding to 80 ° C. which is the maximum temperature in the high temperature region. As described above, the start air pressure Ps3 or the pressure increase coefficient a3 is set.

The control of the electropneumatic regulator 51 (52) by the control unit 6 is performed as follows.
When acquiring the detection value of the temperature sensor 76, the control unit 6 selects a temperature region including the detection value with reference to the lookup table 6a (see FIG. 7).
For example, when the detected value of the temperature sensor 76 is 15 ° C., the control unit 6 refers to the lookup table 6a and selects the low temperature region (10 to 20 ° C.) as the temperature region including the detected value.

  Next, the control unit 6 determines the pressure increase coefficient a corresponding to the selected temperature region with reference to the lookup table 6a. For example, when the selected temperature region is the low temperature region, the control unit 6 refers to the lookup table 6a and determines the pressure increase coefficient a1 corresponding to the low temperature region as the pressure increase coefficient a.

  Next, the control unit 6 calculates the air pressure from the above equation using the determined pressure increase coefficient a, and instructs the electropneumatic regulator 51 (52) to adjust to the calculated air pressure. For example, when the determined pressure increase coefficient a is the pressure increase coefficient a1 in the low temperature region, the control unit 6 causes the electropneumatic regulator 51 (52) to change the pressure corresponding to the low temperature region indicated by the solid line in FIG. Instruct the adjustment air pressure.

[Effect verification by example and comparative example]
In order to verify the effects obtained by the bellows pump device 1 of the present embodiment, a verification test conducted by the present inventors will be described. In this verification test, the change in discharge pressure of the transfer fluid discharged from the bellows pump is compared and evaluated for the example by the control of the electropneumatic regulator of this embodiment and the comparative example by the control of the conventional electropneumatic regulator. The effect was verified.

FIG. 10 is a graph showing changes in the discharge pressure of the transfer fluid discharged from the bellows pump under the control of the electropneumatic regulator according to Comparative Example 1.
In this comparative example 1, when the temperature of the transfer fluid is included in the low temperature region, the discharge pressure of the transfer fluid discharged from the bellows pump when the electropneumatic regulator is controlled using the pressure increase coefficient corresponding to the intermediate temperature region. It is a graph to show.

  In Comparative Example 1 shown in FIG. 10, the discharge pressure of the transfer fluid decreases while the bellows is contracted, as indicated by the arrows in the figure. This decrease in the discharge pressure corresponds to the middle temperature region, which is lower than the air pressure corresponding to the low temperature region when the bellows contracts, although the bellows is hard and difficult to contract due to the temperature drop of the transfer fluid. It is thought that the cause is that the compressed air of pneumatic pressure is supplied to the air chamber and the air pressure acting on the bellows is insufficient.

FIG. 11 is a graph showing a change in the discharge pressure of the transfer fluid discharged from the bellows pump under the control of the electropneumatic regulator according to the first embodiment.
In the first embodiment, when the temperature of the transfer fluid is included in the low temperature region, the discharge pressure of the transfer fluid discharged from the bellows pump when the electropneumatic regulator is controlled using the pressure increase coefficient corresponding to the low temperature region. It is a graph to show.

  In Example 1 shown in FIG. 11, while the bellows contracts, the discharge pressure of the transfer fluid hardly changes. Therefore, comparing Comparative Example 1 in FIG. 10 with Example 1 in FIG. 11, when the temperature of the transfer fluid is included in the low temperature region, the pressure increase coefficient corresponding to the low temperature region is higher than the pressure increase coefficient corresponding to the intermediate temperature region. It can be seen that controlling the electropneumatic regulator using the pressure suppresses the change in the discharge pressure of the transfer fluid discharged from the bellows pump.

FIG. 12 is a graph showing changes in the discharge pressure of the transfer fluid discharged from the bellows pump under the control of the electropneumatic regulator according to Comparative Example 2.
In this comparative example 2, when the temperature of the transfer fluid is included in the high temperature region, the discharge pressure of the transfer fluid discharged from the bellows pump when the electropneumatic regulator is controlled using the pressure increase coefficient corresponding to the medium temperature region. It is a graph to show.

  In Comparative Example 2 shown in FIG. 12, the discharge pressure of the transfer fluid rises while the bellows is contracted, as indicated by the arrows in the figure. This increase in discharge pressure corresponds to the middle temperature range, which is higher than the air pressure corresponding to the high temperature range when the bellows contracts, despite the fact that the bellows becomes soft and easy to contract due to the temperature rise of the transfer fluid. This is considered to be caused by the fact that the pressurized air of air pressure is supplied to the air chamber and excessive air pressure acts on the bellows.

FIG. 13 is a graph showing changes in the discharge pressure of the transfer fluid discharged from the bellows pump under the control of the electropneumatic regulator according to the second embodiment.
In the second embodiment, when the temperature of the transfer fluid is included in the high temperature region, the discharge pressure of the transfer fluid discharged from the bellows pump when the electropneumatic regulator is controlled using the pressure increase coefficient corresponding to the high temperature region. It is a graph to show.

  In Example 2 shown in FIG. 13, while the bellows contracts, the discharge pressure of the transfer fluid hardly changes. Therefore, comparing Comparative Example 2 in FIG. 12 with Example 2 in FIG. 13, when the temperature of the transfer fluid is included in the high temperature region, the pressure increase coefficient corresponding to the high temperature region is higher than the pressure increase coefficient corresponding to the intermediate temperature region. It can be seen that controlling the electropneumatic regulator using the pressure suppresses the change in the discharge pressure of the transfer fluid discharged from the bellows pump.

FIG. 14 is a graph showing changes in the discharge pressure of the transfer fluid discharged from the bellows pump under the control of the electropneumatic regulator according to the third embodiment.
In the third embodiment, when the temperature of the transfer fluid is included in the intermediate temperature region, the discharge pressure of the transfer fluid discharged from the bellows pump when the electropneumatic regulator is controlled using the pressure increase coefficient corresponding to the intermediate temperature region. It is a graph to show.

  In Example 3 shown in FIG. 14, while the bellows is contracting, the discharge pressure of the transfer fluid hardly changes. Therefore, the pressure increase coefficient corresponding to the intermediate temperature region is higher than the temperature of the transfer fluid as compared with the case where the temperature of the transfer fluid is included in the low temperature region or the high temperature region as in Comparative Example 1 in FIG. 10 and Comparative Example 2 in FIG. It can be seen that the change in the discharge pressure of the transfer fluid discharged from the bellows pump can be suppressed when it is included in the medium temperature region.

  As described above, according to the bellows pump device 1 of the present embodiment, the controller 6 supplies the discharge-side air chamber 21 to the discharge-side air chamber 21 during the contraction operation of the bellows 13 (14) as the temperature of the transfer fluid detected by the temperature sensor 76 decreases. The electropneumatic regulator 51 (52) is controlled so that the pressure increase coefficient a of the air pressure of the pressurized air is increased. Thereby, for example, even if the temperature of the transfer fluid is lowered and the bellows 13 (14) is hardened, the pressure increase coefficient of the air pressure of the pressurized air supplied to the discharge-side air chamber 21 is increased, so that the transfer fluid The bellows 13 (14) can be contracted at an air pressure higher than the air pressure before the temperature drop. Therefore, even if the hardness of the bellows 13 (14) changes due to the temperature change of the transfer fluid, it is possible to suppress the change in the discharge pressure of the transfer fluid while the bellows 13 (14) is contracted.

  Further, the starting air pressure Ps1 to Ps3 or the pressure increase coefficient a in the air pressure of the pressurized air is set based on the detection value of the temperature sensor 76 so that the maximum value of the air pressure does not exceed the allowable pressure resistance of the bellows 13 (14). Therefore, even if the pressure increase coefficient a of the air pressure increases, the maximum value of the air pressure does not exceed the allowable pressure resistance of the bellows 13 (14). Therefore, it is possible to prevent the bellows 13 (14) from being deformed or damaged due to an increase in air pressure.

  Moreover, since the control part 6 has the lookup table 6a in which the pressure increase coefficient a was set corresponding to each of several temperature area | region, based on this lookup table 6a, the electropneumatic regulator 51 (52) can be made easy. Can be controlled.

[Modification]
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 bellows pump 10 includes a bellows pump in which a pair of left and right bellows are integrally connected by a tie rod, a bellows pump configured by replacing one of the pair of bellows with an accumulator, or a pair of bellows pumps. The present invention can also be applied to other bellows pumps such as a single type bellows pump composed of only one of the bellows.

  Further, although the electropneumatic regulators 51 and 52 are arranged on the upstream side of the electromagnetic valves 4 and 5, they may be arranged on the downstream side of the electromagnetic valves 4 and 5. However, in this case, since the impact pressure generated when the solenoid valves 4 and 5 are switched acts on the primary side of the electropneumatic regulators 51 and 52, from the viewpoint of preventing failure of the electropneumatic regulators 51 and 52. The electropneumatic regulators 51 and 52 are preferably arranged upstream of the solenoid valves 4 and 5.

6 Control Unit 7 Temperature Detection Unit 6a Look-up Table 13 First Bellows (Bellows)
14 Second bellows (bellows)
21 Discharge side air chamber (air chamber)
51 First electropneumatic regulator (electropneumatic regulator)
52 Second electropneumatic regulator (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,
An electropneumatic regulator that adjusts the air pressure of the pressurized air supplied to the air chamber to increase in accordance with the contraction characteristics of the bellows during the contraction operation of the bellows;
A temperature detector for detecting the temperature of the transfer fluid;
A control unit for controlling the electropneumatic regulator so that a pressure increase coefficient when increasing the air pressure increases as the detection value of the temperature detection unit decreases;
A bellows pump device comprising:   The bellows pump according to claim 1, wherein the control unit sets a pressure increase coefficient of the air pressure so that the maximum value of the air pressure does not exceed an allowable pressure resistance of the bellows based on a detection value of the temperature detection unit. apparatus.   The said control part has a lookup table in which the said pressure increase coefficient was set corresponding to each of several temperature area | regions, and controls the said electropneumatic regulator based on the said lookup table. Bellows pump device.

Images