JP7120899B2 - Bellows pump device - Google Patents

Description

The present invention relates to bellows pump devices.

For example, as a bellows pump used to deliver transfer fluids such as chemicals and solvents in the semiconductor manufacturing and chemical industries, etc., a pair of bellows that draws in and discharges the transfer fluid by expanding and contracting independently of each other. , and an air cylinder for expanding and contracting each bellows by supplying and discharging compressed air (see, for example, Patent Document 1). The bellows pump described in Patent Document 1 drives each air cylinder so that before one bellows reaches its most contracted state (end of discharge), the other bellows is contracted from its most stretched state and the transfer fluid is discharged. is controlling

By controlling the driving of each air cylinder as described above, at the timing of switching from contraction of one bellows to extension (from discharge of transfer fluid to suction), the other bellows already contracts and discharges transfer fluid. be in a state where As a result, it is possible to reduce a large drop in the discharge pressure of the transfer fluid at the switching timing. As a result, pulsation on the discharge side of the bellows pump can be reduced.

JP-A-2004-293502

The bellows pump is equipped with a check valve that prevents backflow of the transfer fluid in a discharge process in which the transfer fluid is discharged by contraction of each bellows. When one of the bellows switches from the discharge process to the suction process, the check valve that was opened in the discharge process to allow the transfer fluid to be discharged is pressed by the transfer fluid discharged from the other bellows and closed. It is designed to

However, when one of the bellows switches from the discharge process to the suction process, the other bellows has already contracted as described above and is discharging the high-pressure transfer fluid. closed rapidly. Therefore, the impact when the check valve closes rapidly is transmitted to the discharge pipe for the transfer fluid connected to the bellows pump, and as shown in FIG. 10, a surge pressure ( There was a problem that the part surrounded by the dashed line) occurred.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and provides a bellows pump device capable of reducing pulsation and suppressing the generation of surge pressure on the discharge side when switching from discharge to suction of transfer fluid. intended to provide

(1) A bellows pump device of the present invention comprises a pump head having a suction passage and a discharge passage for a fluid to be transferred, and a pump head which is independently telescopically attached to the pump head so that the fluid is transferred from the suction passage to the inside by extension. A first bellows and a second bellows for discharging the transfer fluid from the inside to the discharge passage by suction and contraction, and allowing the transfer fluid to flow in one direction with respect to the suction passage and the discharge passage while allowing the transfer fluid to flow in the other direction. It has a check valve for preventing flow, a first suction-side fluid chamber and a first discharge-side fluid chamber, and supplies pressurized fluid to the first suction-side fluid chamber to extend the first bellows to the maximum extension state. a first drive unit that expands and supplies pressurized fluid to the first discharge-side fluid chamber to contract the first bellows to the most contracted state; a second suction-side fluid chamber and a second discharge-side fluid chamber; By supplying pressurized fluid to the second suction side fluid chamber, the second bellows is extended to the maximum extension state, and by supplying pressurized fluid to the second discharge side fluid chamber, the second a second drive unit for contracting the bellows to the maximum contraction state, wherein the second bellows contracts from the maximum contraction state before the first bellows reaches the maximum contraction state, and the second bellows reaches the maximum contraction state. A bellows pump device in which the first bellows is contracted from the most extended state before the first bellows is expanded, the first fluid pressure adjustment adjusting the first fluid pressure of the pressurized fluid in the first discharge-side fluid chamber of the first drive unit a second fluid pressure adjusting portion for adjusting a second fluid pressure of the pressurized fluid in the second discharge-side fluid chamber of the second driving portion; and the first bellows after the second bellows starts contracting. until the first bellows reaches the maximum contraction state, the first fluid pressure adjusting unit is controlled so that the first fluid pressure decreases stepwise or continuously, and after the first bellows starts contracting, the first and a control unit that controls the second fluid pressure adjustment unit so that the second fluid pressure decreases stepwise or continuously until the second bellows reaches the most contracted state.

According to the present invention, before one of the first bellows and the second bellows reaches the most contracted state, the other bellows contracts from the most stretched state. As a result, at the timing when one bellows is switched from contraction to extension (from discharging to sucking in the transported fluid), the other bellows has already contracted and is discharging the fluid. can be reduced. As a result, pulsation on the discharge side of the bellows pump device can be reduced.

In addition, the control unit gradually or continuously increases the fluid pressure of the discharge-side fluid chamber corresponding to the other bellows from when one of the bellows starts to contract until the other bellows is in the most contracted state. The fluid pressure adjusting portion corresponding to the discharge side fluid chamber is controlled so as to decrease. By this control, the check valve that allows the flow of transfer fluid from the other bellows to the discharge passage gradually moves from the open state to the closing direction until the other bellows reaches the maximum contraction state. do. As a result, when the other bellows is switched from the most contracted state to the expanded state, the impact caused by the rapid closing of the check valve can be mitigated. As a result, it is possible to suppress the generation of surge pressure on the discharge side of the bellows pump device when the transfer fluid is switched from being discharged to being sucked.

(2) The control unit controls the first fluid pressure adjustment unit so that the first fluid pressure becomes zero before the first bellows reaches the maximum contraction state, and the second bellows contracts the maximum. It is preferable to control the second fluid pressure adjusting section so that the second fluid pressure becomes zero before the state is reached.
In this case, after one bellows starts contracting and before the other bellows reaches its most contracted state, the fluid pressure in the discharge-side fluid chamber corresponding to the other bellows decreases stepwise or continuously. becomes zero. By reducing the fluid pressure in the discharge-side fluid chamber in this manner, the check valve corresponding to the other bellows is closed before the other bellows reaches the most contracted state. This can prevent the check valve from closing rapidly when the other bellows is switched from the most contracted state to the expanded state. As a result, it is possible to further suppress generation of surge pressure on the discharge side of the bellows pump device when switching from discharge to suction of the transfer fluid.

(3) The control unit controls the first fluid pressure adjustment unit so that the first fluid pressure becomes zero when the first bellows reaches its maximum contraction state, and the second bellows is maximized. It is preferable to control the second fluid pressure adjusting section so that the second fluid pressure becomes zero when the contracted state is reached.
In this case, the fluid pressure in the discharge-side fluid chamber corresponding to the other bellows decreases stepwise or continuously during the period from when one bellows starts to contract until the other bellows is in the most contracted state. , becomes zero when the other bellows is in the most contracted state. As a result, the check valve corresponding to the other bellows closes more slowly than when the fluid pressure becomes zero before the other bellows is fully contracted. As a result, it is possible to further suppress generation of surge pressure on the discharge side of the bellows pump device when switching from discharge to suction of the transfer fluid.

According to the present invention, it is possible to reduce pulsation and suppress the generation of surge pressure on the discharge side when switching from discharge to suction of transfer fluid.

1 is a schematic configuration diagram of a bellows pump device according to an embodiment of the present invention; FIG. 1 is a cross-sectional view of a bellows pump; FIG. It is explanatory drawing which shows operation|movement of a bellows pump. It is explanatory drawing which shows operation|movement of a bellows pump. 4 is a time chart showing an example of control of an electropneumatic regulator by a control unit; 4 is a graph showing the discharge pressure of transfer fluid discharged from a discharge passage of a bellows pump; 5 is a time chart showing first to third modified examples of control of the electropneumatic regulator by the control unit; FIG. 11 is a time chart showing fourth and fifth modifications of control of the electropneumatic regulator by the controller; FIG. FIG. 11 is a time chart showing a sixth modified example of control of the electropneumatic regulator by the controller; FIG. It is a graph which shows the pressure in the discharge piping in the conventional bellows pump.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.
[Overall Configuration of Bellows Pump Device]
FIG. 1 is a schematic configuration diagram of a bellows pump device according to an embodiment of the present invention. The bellows pump device of the present embodiment is used, for example, in semiconductor manufacturing equipment when supplying a constant amount of a transfer target (transfer fluid) such as a chemical liquid or a solvent. This bellows pump device includes a bellows pump 1, an air supply device 2 such as an air compressor that supplies pressurized air (pressurized fluid) to the bellows pump 1, and a mechanical regulator 3 that adjusts the air pressure of the pressurized air. , a first electro-pneumatic regulator (first fluid pressure adjustment unit) 51, a second electro-pneumatic regulator (second fluid pressure adjustment unit) 52, a first solenoid valve 4 and a second solenoid valve 5, and a control unit 6 It has

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

[Construction of bellows]
The first bellows 13 and the second bellows 14 are made of a fluororesin such as polytetrafluoroethylene (PTFE) or tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and are formed into a cylindrical shape with a bottom. A flange portion 13a and a flange portion 14a integrally formed at the open ends of the first and second bellows 13 and 14 are pressed and fixed to the side surface of the pump head 11 in an airtight manner. Each of the peripheral walls of the first and second bellows 13 and 14 is formed in a bellows shape and configured to be horizontally expandable and contractable independently of each other.

Specifically, the first and second bellows 13 and 14 are in a maximum extension state in which the outer surface of the operation plate 19 (described later) contacts the inner side surface of the bottom wall portion 121 of the pump case 12, and a piston body 23 (described later). The inner side surface of the pump case 12 expands and contracts between the most contracted state and the outer side surface of the bottom wall portion 121 of the pump case 12 . An operating plate 19 is fixed to the outer surface of the bottom of the first and second bellows 13 and 14 by bolts 17 and nuts 18 together with one end of a connecting member 20 .

[Configuration of pump case]
The opening periphery of the bottomed cylindrical pump case 12 (hereinafter also referred to as “first pump case 12A”) is airtightly pressed and fixed to the flange portion 13a of the first bellows 13. there is As a result, a first discharge-side air chamber (first discharge-side fluid chamber) 21A that is kept airtight is formed inside the first pump case 12A.

A first intake/exhaust port 22A is provided in the first pump case 12A. 2 (see FIG. 1). As a result, pressurized air is supplied from the air supply device 2 to the inside of the first discharge side air chamber 21A through the mechanical regulator 3, the first electro-pneumatic regulator 51, the first solenoid valve 4, and the first intake/exhaust port 22A. By continuing to supply, the first bellows 13 contracts to the maximum contraction state.

The opening peripheral portion of the bottomed cylindrical pump case 12 (hereinafter also referred to as “second pump case 12B”) is airtightly pressed and fixed to the flange portion 14a of the second bellows 14. there is As a result, a second discharge-side air chamber (second discharge-side fluid chamber) 21B that is kept airtight is formed inside the second pump case 12B.

A second intake/exhaust port 22B is provided in the second pump case 12B, and the second intake/exhaust port 22B supplies air via the second solenoid valve 5, the second electropneumatic regulator 52, and the mechanical regulator 3. It is connected to the device 2 (see FIG. 1). As a result, pressurized air is supplied from the air supply device 2 to the inside of the second discharge side air chamber 21B via the mechanical regulator 3, the second electro-pneumatic regulator 52, the second solenoid valve 5, and the second intake/exhaust port 22B. By continuing to supply, the second bellows 14 contracts to the maximum contraction state.

The connecting member 20 is horizontally slidably supported by the bottom wall portion 121 of each of the pump cases 12A and 12B. ing. The piston body 23 is slidably supported in the horizontal direction while maintaining an airtight state on the inner peripheral surface of a cylindrical cylinder body 25 integrally provided on the outer side surface of the bottom wall portion 121 . there is

As a result, on the first pump case 12A side, the space surrounded by the bottom wall portion 121, the cylinder body 25, and the piston body 23 becomes a first suction-side air chamber (first suction-side fluid chamber) whose airtight state is maintained. ) 26A. Further, on the second pump case 12B side, the space surrounded by the bottom wall portion 121, the cylinder body 25, and the piston body 23 is a second suction-side air chamber (second suction-side fluid chamber) whose airtight state is maintained. 26B.

The cylinder body 25 on the first pump case 12A side is formed with an intake/exhaust port 251 that communicates with the first suction side air chamber 26A. The intake/exhaust port 251 is connected to the air supply device 2 via the first solenoid valve 4, the first electro-pneumatic regulator 51 and the mechanical regulator 3 (see FIG. 1). As a result, pressurized air is supplied from the air supply device 2 to the inside of the first suction side air chamber 26A through the mechanical regulator 3, the first electropneumatic regulator 51, the first solenoid valve 4, and the intake/exhaust port 251. By continuing, the first bellows 13 is extended to the maximum extension state.

The cylinder body 25 on the side of the second pump case 12B is formed with an intake/exhaust port 252 that communicates with the second suction side air chamber 26B. The intake/exhaust port 252 is connected to the air supply device 2 via the second solenoid valve 5, the second electro-pneumatic regulator 52 and the mechanical regulator 3 (see FIG. 1). As a result, pressurized air is supplied from the air supply device 2 to the inside of the second suction side air chamber 26B via the mechanical regulator 3, the second electro-pneumatic regulator 52, the second solenoid valve 5, and the intake/exhaust port 252. By continuing, the second bellows 14 is extended to the maximum extension state.

With the above configuration, the first bellows 13 is fully extended by the first pump case 12A in which the first discharge side air chamber 21A is formed, and the piston body 23 and the cylinder body 25 which form the first suction side air chamber 26A. A first air cylinder portion (first driving portion) 27 is configured to continuously extend and contract between the state and the most contracted state.
Further, the second bellows 14 is moved to the maximum extension state and the maximum state by the second pump case 12B in which the second discharge side air chamber 21B is formed, and the piston body 23 and the cylinder body 25 which form the second suction side air chamber 26B. A second air cylinder portion (second driving portion) 28 is configured to continuously expand and contract between the contracted state and the contracted state.

[Structure of detector]
A pair of proximity sensors 29A and 29B are attached to the cylinder body 25 of the first air cylinder portion 27 . A detected plate 30 is attached to the piston body 23 of the first air cylinder portion 27 to be detected by the respective proximity sensors 29A and 29B. The detected plate 30 is detected by alternately approaching the proximity sensors 29A and 29B by reciprocating together with the piston body 23 .

The proximity sensor 29A is arranged at a position where it detects the detected plate 30 when the first bellows 13 is in the most contracted state. The proximity sensor 29B is arranged at a position where it detects the plate 30 to be detected when the first bellows 13 is in the fully extended state. A detection signal of each proximity sensor 29A, 29B is transmitted to the control unit 6 . In the present embodiment, the pair of proximity sensors 29A and 29B constitute a first detection section 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 . A detection target plate 32 is attached to the piston body 23 of the second air cylinder portion 28 to be detected by the respective proximity sensors 31A and 31B. The detected plate 32 is detected by alternately approaching the proximity sensors 31A and 31B by reciprocating together with the piston body 23 .

The proximity sensor 31A is arranged at a position where it detects the detected plate 32 when the second bellows 14 is in the most contracted state. The proximity sensor 31B is arranged at a position where it detects the detected plate 32 when the second bellows 14 is in the most extended state. A detection signal of each proximity sensor 31A, 31B is transmitted to the control unit 6 . In this embodiment, the pair of proximity sensors 31A and 31B constitute a second detection unit 31 that detects the expansion/contraction state of the second bellows 14 .

The pressurized air generated by the air supply device 2 is supplied to the first suction side of the first air cylinder portion 27 by alternately detecting the plate 30 to be detected by the pair of proximity sensors 29A and 29B of the first detection portion 29. The air is alternately supplied to the air chamber 26A and the first discharge side air chamber 21A. As a result, the first bellows 13 continuously expands and contracts.

Also, the pressurized air generated by the air supply device 2 is detected by the pair of proximity sensors 31A and 31B of the second detection section 31 alternately detecting the plate 32 to be detected, so that the second pressure air of the second air cylinder section 28 is detected. The air is alternately supplied to the suction side air chamber 26B and the second discharge side air chamber 21B. Thereby, the second bellows 14 continuously expands and contracts. At that time, the expansion operation of the second bellows 14 is performed when the first bellows 13 is contracted, and the contraction operation of the second bellows 14 is mainly performed when the first bellows 13 is expanded. In this way, the first bellows 13 and the second bellows 14 alternately repeat expansion and contraction, so that the transfer fluid is alternately sucked into and discharged from the bellows 13 and 14, and the transfer fluid is to be transported.

Although the first and second detection units 29 and 31 are configured by proximity sensors, they may be configured by other detection means such as limit switches. Further, the first and second detection units 29 and 31 detect the maximum expansion state and the maximum expansion/contraction state of the first and second bellows 13 and 14. good.

[Configuration of pump head]
The pump head 11 is made of fluororesin such as PTFE and PFA. A suction passage 34 and a discharge passage 35 for the transfer fluid are formed inside the pump head 11 . The suction passage 34 and the discharge passage 35 are opened on the outer peripheral surface of the pump head 11 and connected to a suction port and a discharge port (both not shown) provided on the outer peripheral surface.

The suction port is connected to a storage tank or the like for the transfer fluid, and the discharge port is connected to the transfer destination of the transfer fluid. The suction passage 34 and the discharge passage 35 are branched toward the left and right side surfaces of the pump head 11 , respectively, and have a suction port 36 and a discharge port 37 that open at 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, 14 via check valves 15, 16, respectively.

[Configuration of check valve]
Each suction port 36 and each discharge port 37 are provided with check valves 15 and 16 .
The check valve 15 attached to the suction port 36 (hereinafter also referred to as a "check valve for suction") includes a valve case 15a, a valve body 15b housed in the valve case 15a, and a valve body 15b in the valve closing direction. It has a compression coil spring 15c that biases it.

The valve case 15a is formed in a bottomed cylindrical shape. A through hole 15d communicating with the inside of the bellows 13, 14 is formed in the bottom wall of the valve case 15a. 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 acts due to the flow of the transferred fluid accompanying expansion and contraction of the bellows 13 and 14. It is designed to

As a result, the suction check valve 15 opens when the bellows 13, 14 in which it is arranged expands, and transfers fluid in the direction (one direction) from the suction passage 34 toward the inside of the bellows 13, 14. allow aspiration of In addition, the suction check valve 15 is closed when the bellows 13, 14 in which it is arranged is contracted, and the transfer fluid flows from the inside of the bellows 13, 14 toward the suction passage 34 (the other direction). Prevent backflow.

A check valve 16 (hereinafter also referred to as a "discharge check valve") attached to the discharge port 37 includes a valve case 16a, a valve body 16b housed in the valve case 16a, and a valve body 16b in the valve closing direction. It has a compression coil spring 16c that biases it.

The valve case 16a is formed in a bottomed cylindrical shape. A through hole 16d communicating with the inside of the bellows 13, 14 is formed in the bottom wall of the valve case 16a. 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 the expansion and contraction of the bellows 13 and 14 acts, the valve case 16a is penetrated. The hole 16d is opened (valve opened).

As a result, the discharge check valve 16 opens when the bellows 13, 14 in which it is arranged is contracted, and transfers fluid in the direction (one direction) from the inside of the bellows 13, 14 toward the discharge passage 35. permissible outflow. Further, the discharge check valve 16 closes when the bellows 13, 14 in which it is arranged expands, and the transfer fluid flows from the discharge passage 35 toward the inside of the bellows 13, 14 (the other direction). Prevent backflow.

[Bellows pump operation]
Next, the operation of the bellows pump 1 of this embodiment will be described with reference to FIGS. 3 and 4. FIG. In addition, in FIG.3 and FIG.4, the structure of the 1st and 2nd bellows 13 and 14 is simplified and shown.
As shown in FIG. 3, when the first bellows 13 contracts and the second bellows 14 expands, each valve body of the suction check valve 15 and the discharge check valve 16 mounted on the left side of the pump head 11 in the drawing 15b and 16b receive pressure from the transfer fluid in the first bellows 13 and move to the right side of each valve case 15a and 16a in the drawing. As a result, the suction check valve 15 is closed, the discharge check valve 16 is opened, and the transfer fluid in the first bellows 13 is discharged from the discharge passage 35 to the outside of the pump.

On the other hand, the valve body 15b of the suction check valve 15 mounted on the right side of the pump head 11 in the drawing moves to the right side of the valve case 15a in the drawing due to the suction action of the second bellows 14. FIG. Also, the valve body 16b of the discharge check valve 16 mounted on the right side of the pump head 11 in the figure has a suction action by the second bellows 14 and a pressing action by the transfer fluid discharged from the first bellows 13 into the discharge passage 35. , the valve case 16a moves to the right side in the figure. As a result, the check valve 15 for suction is opened, the check valve 16 for discharge 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 expands and the second bellows 14 contracts, 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 Each valve element 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 drawing. As a result, the suction check valve 15 is closed, the discharge check valve 16 is opened, and the transfer fluid in the second bellows 14 is discharged from the discharge passage 35 to the outside of the pump.

On the other hand, the valve body 15b of the suction check valve 15 mounted on the left side of the pump head 11 in the drawing moves to the left side of the valve case 15a in the drawing due to the suction action of the first bellows 13 . Further, the valve body 16b of the discharge check valve 16 mounted on the left side of the pump head 11 in the figure has a suction action by the first bellows 13 and a pressing action by the transfer fluid discharged from the first bellows 13 into the discharge passage 35. , the valve case 16a moves to the left in the figure. 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 operations, the left and right bellows 13 and 14 can alternately perform suction and discharge of the transfer fluid.

[Configuration of solenoid valve]
In FIG. 1, the first electromagnetic valve 4 supplies and discharges pressurized air to and from one of the first discharge side air chamber 21A and the first suction side air chamber 26A of the first air cylinder portion 27, and It switches the supply and discharge of pressurized air to the other air chamber. The first electromagnetic valve 4 is, for example, a three-position electromagnetic switching valve having a pair of solenoids 4a and 4b. Each solenoid 4a, 4b is excited based on a command signal received from the control section 6. As shown in FIG.

The second solenoid valve 5 supplies and discharges pressurized air to and from one of the second discharge side air chamber 21B and the second suction side air chamber 26B of the second air cylinder portion 28 and the other air chamber. It switches the supply and discharge of pressurized air to. The second solenoid valve 5 is, for example, a three-position solenoid switching valve having a pair of solenoids 5a and 5b. Each solenoid 5a, 5b receives a command signal from the control unit 6 and is excited.
Although the first and second solenoid valves 4 and 5 of the present embodiment are three-position solenoid switching valves, they may be two-position solenoid switching valves that do not have a neutral position.

In FIG. 1, between the first discharge side air chamber 21A (first intake/exhaust port 22A) of the first air cylinder portion 27 and the first solenoid valve 4, a first rapid exhaust valve 61 is provided to provide first discharge side air flow. It is located adjacent to chamber 21A . The first quick exhaust valve 61 has an exhaust port 61a for discharging pressurized air, allows the pressurized air to flow from the first electromagnetic valve 4 to the first discharge side air chamber 21A, and The pressurized air flowing out of the discharge side air chamber 21A is discharged from the exhaust port 61a. As a result, the pressurized air in the first discharge side air chamber 21A can be quickly discharged from the first rapid exhaust valve 61 without going through the first solenoid valve 4. As shown in FIG.

Similarly, between the second discharge side air chamber 21B (second intake/exhaust port 22B) of the second air cylinder portion 28 and the second electromagnetic valve 5, a second rapid exhaust valve 62 is provided in the second discharge side air chamber. 21B. The second quick exhaust valve 62 has an exhaust port 62a for discharging pressurized air, and allows the pressurized air to flow from the second electromagnetic valve 5 to the second discharge side air chamber 21B. The pressurized air flowing out of the discharge side air chamber 21B is discharged from the exhaust port 62a. As a result, the pressurized air in the second discharge side air chamber 21</b>B can be quickly discharged from the second rapid exhaust valve 62 without going through the second solenoid valve 5 .

[Configuration of control unit]
The control unit 6 switches the electromagnetic valves 4 and 5 based on the detection results of the first detection unit 29 and the second detection unit 31 (see FIG. 2), thereby controlling the first air cylinder unit 27 of the bellows pump 1 and the It controls each drive of the second air cylinder portion 28 .

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

Here, "before" the first bellows 13 is in the most contracted state means that the contraction progress position of the first bellows 13 is closer to the contraction end position (maximum contraction position) than the contraction start position (maximum contraction position). More specifically, 60% to 90% (preferably 60% to 70%) of the contraction period T12 (see FIG. 5) from the start of contraction of the first bellows 13 to the most contracted state. , more preferably 66%). Similarly, "before" the second bellows 14 is in the most contracted state means that the contracted position of the second bellows 14 is closer to the contraction end position (most contracted position) than the contraction start position (most stretched position). More specifically, the second bellows 14 is 60% to 90% (preferably 60% to 70%) of the contraction period T22 (see FIG. 5) from the start of contraction to the most contracted state. %, more preferably 66%).

As a result, at the timing when one bellows is switched from contraction to extension (from discharge to suction of the transfer fluid), the other bellows has already contracted and is discharging the transfer fluid, so the discharge pressure of the transfer fluid is can be reduced. As a result, pulsation on the discharge side of the bellows pump 1 can be reduced.

[Structure of electro-pneumatic regulator]
1 and 2, the first electropneumatic regulator 51 is arranged between the mechanical regulator 3 and the first solenoid valve 4. As shown in FIG. The first electro-pneumatic regulator 51 controls the air pressure of the pressurized air in the first suction side air chamber 26A of the first air cylinder portion 27 and the air pressure of the pressurized air in the first discharge side air chamber 21A of the first air cylinder portion 27. (first fluid pressure) is adjusted.

Similarly, a second electropneumatic regulator 52 is arranged between the mechanical regulator 3 and the second solenoid valve 5 . The second electro-pneumatic regulator 52 controls the air pressure of the pressurized air in the second suction side air chamber 26B of the second air cylinder portion 28 and the air pressure of the pressurized air in the second discharge side air chamber 21B of the second air cylinder portion 28. (second fluid pressure) is adjusted.

The electropneumatic regulators 51 and 52 are arranged on the upstream side of the solenoid valves 4 and 5, but may be arranged on the downstream side of the solenoid valves 4 and 5. However, in this case, the primary side of the electropneumatic regulators 51 and 52 is subjected to the impact pressure generated when the solenoid valves 4 and 5 are switched. , electropneumatic regulators 51 and 52 are preferably arranged upstream of the solenoid valves 4 and 5, respectively.

Moreover, the electro-pneumatic regulators 51 and 52 should just adjust the air pressure of the pressurized air in at least the discharge side air chambers 21A and 21B. Further, in this embodiment, the electro-pneumatic regulators 51 and 52 for directly adjusting the air pressure are used as the fluid pressure adjusting section, but the air pressure is indirectly adjusted using an air flow rate adjusting valve for adjusting the air flow rate. Alternatively, a device that adjusts the pressure or flow rate of a gas other than air (for example, nitrogen) or liquid may be used.

[Electro-pneumatic regulator control example]
FIG. 5 is a time chart showing an example of control of the electro-pneumatic regulator 51 (52) by the controller 6 of this embodiment. In FIG. 5, the control unit 6 sets the air pressure of the first suction side air chamber 26A of the first air cylinder unit 27 to a constant value P during the extension period T11 during which the first bellows 13 is extended. 1 controls the electropneumatic regulator 51;

Further, the control unit 6 controls the first contraction time T121 from the contraction start time t1 of the first bellows 13 to the contraction start time t2 of the second bellows 14 in the contraction period T12 in which the first bellows 13 is contracted. , the first electropneumatic regulator 51 is controlled so that the air pressure in the first discharge side air chamber 21A of the first air cylinder portion 27 becomes a constant value P.

Next, during the contraction period T12, the control unit 6 controls the second contraction time T122 from the contraction start time t2 of the second bellows 14 to the contraction end time t3 when the first bellows 13 is in the most contracted state. , the air pressure in the first discharge side air chamber 21A is continuously reduced from P, and the first electro-pneumatic regulator 51 is controlled so that the air pressure becomes zero before the first bellows 13 reaches the maximum contraction state. For example, the control unit 6 of the present embodiment linearly and continuously decreases the air pressure in the first discharge side air chamber 21A from P, and at the contraction end time t3 when the first bellows 13 reaches the maximum contraction state, the air pressure is controlled to zero.

On the other hand, the control unit 6 controls the second power supply so that the air pressure in the second suction side air chamber 26B of the second air cylinder unit 28 becomes a constant value P during the extension period T21 during which the second bellows 14 is extended. Controls the empty regulator 52 .
Further, the control unit 6 controls the first contraction time T221 from the contraction start time t2 of the second bellows 14 to the contraction start time t1 of the first bellows 13 in the contraction period T22 during which the second bellows 14 contracts. , the second electropneumatic regulator 52 is controlled so that the air pressure in the second discharge side air chamber 21B of the second air cylinder portion 28 becomes a constant value P.

Next, during the contraction period T22, the control unit 6 controls the second contraction time T222 from the contraction start time t1 of the first bellows 13 to the contraction end time t4 when the second bellows 14 is in the most contracted state. , the air pressure in the second discharge side air chamber 21B is continuously reduced from P, and the second electropneumatic regulator 52 is controlled so that the air pressure becomes zero before the second bellows 14 reaches the maximum contraction state. For example, the control unit 6 of the present embodiment linearly and continuously decreases the air pressure of the second discharge side air chamber 21B from P, and at the end of contraction time t4 when the second bellows 14 reaches the maximum contraction state, the air pressure is controlled to zero.

FIG. 6 is a graph showing the discharge pressure of the transfer fluid discharged from the discharge passage 35 of the bellows pump 1 of this embodiment. As shown in FIG. 6, the control unit 6 controls the first and second electropneumatic regulators 51 and 52 as described above to switch one bellows from contraction to expansion (from discharge to suction of transfer fluid). It can be seen that a large drop in the discharge pressure can be reduced at the timing (the part surrounded by the dashed line in the figure). Moreover, when comparing the graph shown in FIG. 6 of the present embodiment and the graph shown in FIG. 10 of the conventional art, it can be seen that the generation of surge pressure can also be suppressed at the switching timing.

[Action and effect of the present embodiment]
As described above, according to the bellows pump device of the present embodiment, the other bellows 14 (13) contracts from the most stretched state before the one bellows 13 (14) reaches the most contracted state. As a result, at the timing of switching one bellows 13 (14) from contraction to extension (from discharging to sucking in the transferred fluid), the other bellows 14 (13) has already contracted and discharged the fluid. It is possible to reduce the drop in ejection pressure at the timing. As a result, pulsation on the discharge side of the bellows pump device can be reduced.

Further, the control unit 6 controls the discharge side corresponding to the other bellows 14 (13) during the period from when the one bellows 13 (14) starts to contract until the other bellows 14 (13) reaches the most contracted state. The electropneumatic regulator 52 (51) corresponding to the discharge side air chamber 21A (21B) is controlled so that the air pressure in the air chamber 21B (21A) is continuously reduced. By this control, the discharge check valve 16 corresponding to the other bellows 14 (13) gradually moves from the open state to the closing direction until the other bellows 14 (13) reaches the maximum contraction state. As a result, when the other bellows 14 (13) is switched from the most contracted state to the expanded state, the shock caused by the rapid closing of the discharge check valve 16 can be mitigated. As a result, it is possible to suppress the generation of surge pressure on the discharge side of the bellows pump device when the transfer fluid is switched from being discharged to being sucked.

Also, after one bellows 13 (14) starts contracting and before the other bellows 14 (13) reaches the most contracted state, the discharge side air chamber 21B (21A) corresponding to the other bellows 14 (13) is closed. air pressure continuously decreases to zero. By reducing the air pressure in the discharge side air chamber 21B (21A) in this way, the discharge check valve 16 corresponding to the other bellows 14 (13) is closed before the other bellows 14 (13) reaches the most contracted state. closes. As a result, when the other bellows 14 (13) switches from the most contracted state to the extended state, it is possible to prevent the discharge check valve 16 from closing rapidly. As a result, it is possible to further suppress generation of surge pressure on the discharge side of the bellows pump device when switching from discharge to suction of the transfer fluid.

Also, during the period from when one bellows 13 (14) starts contracting to when the other bellows 14 (13) is in the most contracted state, the discharge side air chamber 21B (21A) corresponding to the other bellows 14 (13) ) decreases continuously and becomes zero when the other bellows 14 (13) is fully contracted. As a result, compared to the case where the air pressure becomes zero before the other bellows 14 (13) is fully contracted (see FIG. 8), the discharge check valve 16 corresponding to the other bellows 14 (13) is Close slowly. As a result, it is possible to further suppress generation of surge pressure on the discharge side of the bellows pump device when switching from discharge to suction of the transfer fluid.

[Modified Example of Electro-Pneumatic Regulator Control]
FIG. 7 is a time chart showing the first, second and third modifications of the control of the electro-pneumatic regulator 51 (52) by the controller 6. In FIG.
In the first modification shown by the solid line in FIG. 7, the control unit 6 controls the operation from the contraction start time t2 (t1) of one bellows 14 (13) to the contraction end time t3 (t4) of the other bellows 13 (14). During the second contraction time T122 (T222), the air pressure in the discharge side air chamber 21A (21B) is gradually reduced from P, and the electric It controls the air regulator 51 (52). In addition, although the air pressure is decreased in two steps in the first modification, the air pressure may be decreased in three or more steps.

In the second modification shown by the dashed-dotted line in FIG. 7, the control unit 6 changes from the contraction start time t2 (t1) of one bellows 14 (13) to the contraction end time t3 (t4) of the other bellows 13 (14). During the second contraction time T122 (T222) until the contraction end point, the air pressure in the discharge side air chamber 21A (21B) corresponding to the other bellows 13 (14) is continuously decreased from P in a concave curve. The electro-pneumatic regulator 51 (52) is controlled so that the air pressure becomes zero at t3 (t4).

In the third modified example shown by the two-dot chain line in FIG. 7, the control unit 6 changes from the contraction start time t2 (t1) of one bellows 14 (13) to the contraction end time t3 (t4) of the other bellows 13 (14). During the second contraction time T122 (T222) until the contraction end point, the air pressure in the discharge side air chamber 21A (21B) corresponding to the other bellows 13 (14) is continuously decreased from P in a convex curve. The electro-pneumatic regulator 51 (52) is controlled so that the air pressure becomes zero at t3 (t4).

As described above, the first to third modifications shown in FIG. 7 also have the same effect as the above-described embodiment. In the first modified example, the controller 6 controls the electropneumatic regulator 51 (52) so as to linearly reduce the air pressure in the discharge side air chamber 21A (21B) at each stage. As in the second or third modification, the electropneumatic regulator 51 (52) may be controlled so as to reduce the air pressure in a curved line at each step.

FIG. 8 is a time chart showing fourth and fifth modifications of the control of the electro-pneumatic regulator 51 (52) by the control section 6. In FIG.
In the fourth modification shown by the solid line in FIG. 8, the control unit 6 controls the contraction of one bellows 14 (13) from the contraction start time t2 (t1) to before the other bellows 13 (14) reaches the maximum contraction state. The air pressure in the discharge side air chamber 21A (21B) is continuously reduced from P until midway point t5 (t6), and the electro-pneumatic regulator is operated so that the pneumatic pressure becomes zero at point t5 (t6) midway through contraction. 51 (52). Then, the control unit 6 maintains the air pressure of the discharge side air chamber 21A (21B) at zero during the period from the halfway point of contraction t5 (t6) of the other bellows 13 (14) to the end point of contraction t3 (t4). to control the electropneumatic regulator 51 (52).

In the fifth modification shown by the dashed-dotted line in FIG. 8 , the control unit 6 operates from the contraction start time t2 (t1) of one bellows 14 (13) to before the other bellows 13 (14) reaches the maximum contraction state. , the air pressure in the discharge side air chamber 21A (21B) is continuously decreased from P, and the air pressure drops to P'(0<P' The electro-pneumatic regulator 51 (52) is controlled so that <P). Then, the control unit 6 controls the air pressure in the discharge side air chamber 21A (21B) to be zero during the period from time t5 (t6) during contraction of the other bellows 13 (14) to time t3 (t4) at which contraction ends. Then, the electropneumatic regulator 51 (52) is controlled.

As described above, in the fourth and fifth modifications, similarly to the above-described embodiment, the period from when one bellows 14 (13) starts contracting to when the other bellows 13 (14) reaches the maximum contraction state , the air pressure in the discharge side air chamber 21A (21B) corresponding to the other bellows 13 (14) decreases continuously. As a result, when the transfer fluid is switched from being discharged to being sucked, it is possible to reduce pulsation and suppress the generation of surge pressure on the discharge side.

Also, after one bellows 14 (13) starts contracting and before the other bellows 13 (14) reaches the most contracted state, the discharge side air chamber 21A (21B) corresponding to the other bellows 13 (14) is closed. air pressure continuously decreases to zero. By reducing the air pressure in the discharge side air chamber 21A (21B) in this way, the discharge check valve 16 corresponding to the other bellows 13 (14) is opened before the other bellows 13 (14) reaches the most contracted state. closes. As a result, when the other bellows 13 (14) is switched from the most contracted state to the extended state, the discharge check valve 16 can be prevented from closing rapidly. As a result, it is possible to further suppress generation of surge pressure on the discharge side of the bellows pump device when switching from discharge to suction of the transfer fluid.

FIG. 9 is a time chart showing a sixth modification of the control of the electro-pneumatic regulator 51 (52) by the controller 6. In FIG. In this modification, the control unit 6 controls the second contraction time T122 (T222 ), the air pressure in the discharge side air chamber 21A (21B) is continuously reduced from P, and at the end of contraction time t3 when the other bellows 13 (14) is in the most contracted state, the air pressure drops to P'' (0 The electro-pneumatic regulator 51 (52) is controlled so that <P″<P). When the corresponding solenoid valve 4 (5) switches at the contraction end point t3 (t4), the pressurized air in the discharge side air chamber 21A (21B) is released to the atmosphere, and the discharge side air chamber 21A ( 21B) air pressure goes from P″ to zero.

As described above, in the sixth modified example, similarly to the above-described embodiment, after one bellows 14 (13) starts contracting until the other bellows 13 (14) reaches the maximum contraction state, the other bellows 13 (14) The air pressure in the discharge side air chamber 21A (21B) corresponding to the bellows 13 (14) decreases continuously. As a result, when the transfer fluid is switched from being discharged to being sucked, it is possible to reduce pulsation and suppress the generation of surge pressure on the discharge side.

8 and 9, the controller 6 linearly and continuously decreases the air pressure in the discharge side air chamber 21A (21B) when controlling the electro-pneumatic regulator 51 (52). However, the air pressure may be decreased stepwise as in the first modified example of FIG. 7, or the air pressure may be decreased continuously in a curved line like the second or third modified example of FIG. You may let

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above-described meaning, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

6 control unit 11 pump head 13 first bellows 14 second bellows 15 suction check valve (check valve)
16 discharge check valve (check valve)
21A First discharge side air chamber (first discharge side fluid chamber)
21B Second discharge side air chamber (second discharge side fluid chamber)
26A First suction side air chamber (first suction side fluid chamber)
26B Second suction side air chamber (second suction side fluid chamber)
27 first air cylinder section (first drive section)
28 Second air cylinder section (second drive section)
34 Suction passage 35 Discharge passage 51 First electropneumatic regulator (first fluid pressure adjustment unit)
52 Second electro-pneumatic regulator (second fluid pressure adjustment unit)

Claims (2)

a pump head having inlet and outlet passages for the fluid to be transferred;
a first bellows and a second bellows, which are attached to the pump head so as to extend and contract independently of each other, suck the transfer fluid into the inside from the suction passage by expansion, and discharge the transfer fluid from the inside to the discharge passage by contraction;
a check valve that allows the transfer fluid to flow in one direction and prevents the transfer fluid from flowing in the other direction to the suction passage and the discharge passage;
It has a first suction-side fluid chamber and a first discharge-side fluid chamber, and by supplying pressurized fluid to the first suction-side fluid chamber, the first bellows is extended to the maximum extension state, and the first discharge-side fluid chamber is provided. a first drive unit that contracts the first bellows to a maximum contraction state by supplying pressurized fluid to the fluid chamber;
It has a second suction-side fluid chamber and a second discharge-side fluid chamber, and by supplying pressurized fluid to the second suction-side fluid chamber, the second bellows is extended to the maximum extension state, and the second discharge-side fluid chamber is provided. a second drive unit for contracting the second bellows to the maximum contraction state by supplying pressurized fluid to the fluid chamber;
A bellows pump device in which the second bellows contracts from the maximum stretched state before the first bellows reaches the maximum contraction state, and the first bellows contracts from the maximum stretched state before the second bellows reaches the maximum contraction state. and
a first fluid pressure adjusting unit that adjusts a first fluid pressure of the pressurized fluid in the first discharge-side fluid chamber of the first driving unit;
a second fluid pressure adjusting unit that adjusts a second fluid pressure of the pressurized fluid in the second discharge-side fluid chamber of the second driving unit;
The first fluid pressure adjusting unit is controlled so that the first fluid pressure decreases stepwise or continuously from the time when the second bellows starts to contract until the time when the first bellows reaches the maximum contraction state. and the second fluid pressure adjusting portion is adjusted so that the second fluid pressure decreases stepwise or continuously from the time when the first bellows starts to contract until the time when the second bellows reaches the maximum contraction state. and a control unit for controlling the
The control unit controls the first fluid pressure adjustment unit so that the first fluid pressure becomes zero before the first bellows reaches its maximum contraction state, and the second bellows reaches its maximum contraction state. A bellows pump device that previously controls the second fluid pressure regulator such that the second fluid pressure is zero . The control unit controls the first fluid pressure adjustment unit so that the first fluid pressure becomes zero when the first bellows is in the most contracted state, and the second bellows is in the most contracted state. 2. The bellows pump device according to claim 1 , wherein said second fluid pressure adjusting section is controlled so that said second fluid pressure becomes zero when said second fluid pressure becomes zero.

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