JP2012122380A - Bellows pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bellows pump capable being reduced in size, maintaining sealing accuracy over a long period, and of performing opening/closing operation with excellent responsiveness according to the expansion of a bellows.SOLUTION: The bellows pump 10 includes a pump head 11 forming flow passages 33 and 34 of fluids, the bellows 13 installed in the pump head 11, communicating with the flow passages 33 and 34 and freely expandable in the horizontal direction, and check valves 38 and 40 for allowing a flow of the fluid in one direction to the flow passages 33 and 34 and checking the flow of fluid in the other direction. The check valves 38 and 40 include valve elements 45 stored in the pump head 11 and movable in the valve closing direction by dead weight and cap members 44 and 46 installed on the pump head 11 and checking the valve element 45 when separating from the inside of the pump head 11.

Description

  The present invention relates to a bellows pump.

In semiconductor manufacturing, chemical industry, etc., a bellows pump may be used as a pump for feeding fluids such as chemicals and solvents.
In this bellows pump, for example, as described in Patent Documents 1 and 2, a pump case is connected to both sides of the pump head in the left-right direction (horizontal direction) to form two air chambers. Bellows that can expand and contract in the left-right direction are provided therein, and each bellows is contracted or expanded by alternately supplying pressurized air to each air chamber.

  The pump head is formed with a fluid suction passage and a discharge passage communicating with the inside of the bellows, and further allows a fluid flow in one direction with respect to the suction passage and the discharge passage, and allows a fluid flow in the other direction. A check valve is provided for blocking. The check valve for the suction passage allows the flow of fluid from the suction passage into the bellows by being opened by the extension of the bellows, and blocks the flow of fluid from the inside of the bellows to the suction passage by being closed by the contraction of the bellows. Is configured to do. The check valve for the discharge passage is closed by the extension of the bellows to prevent the flow of fluid from the discharge passage into the bellows, and is opened by the contraction of the bellows, so that the fluid flow from the inside of the bellows to the discharge passage Is configured to allow.

  The check valves described in Patent Documents 1 and 2 are both arranged so that the valve element moves in the expansion / contraction direction (left-right direction) of the bellows within the valve case. In the check valve described in Patent Document 1, the valve body is urged in the valve closing direction by a compression coil spring. In the check valve described in Patent Document 2, the valve body is configured by a ball, It moves by the flow of fluid accompanying expansion and contraction, and opens and closes.

JP 2001-248741 A JP 2006-200909 A

The check valve described in Patent Document 1 has a high sealing performance because the valve body is urged by a compression coil spring, and the operation accompanying the expansion and contraction of the bellows, particularly the switching operation from opening to closing of the check valve, In addition to the back pressure due to the flow of fluid accompanying the expansion and contraction of the bellows, it can be performed with good responsiveness by the biasing force of the compression coil spring. However, since it is necessary to secure the expansion / contraction stroke of the compression coil spring, it is necessary to increase the horizontal dimension of the valve case. Since the valve case is disposed in the bellows, when the horizontal dimension of the valve case is increased, it is necessary to form the bellows longer in the horizontal direction, and there is a disadvantage that the entire bellows pump is increased in size.
In addition, since the compression coil spring is formed of a synthetic resin such as PTFE, there is a possibility that the sealing accuracy may be lowered due to creep or the like due to long-term use.

On the other hand, since the check valve described in Patent Document 2 does not use a compression coil spring, the horizontal dimension of the valve case can be reduced to some extent, which can contribute to the downsizing of the bellows pump. At the same time, it is possible to prevent a decrease in sealing accuracy due to creep or the like.
However, since the valve body (ball) moves only by the flow of the fluid accompanying expansion and contraction of the bellows, it is particularly easy to cause a delay in switching the check valve from opening to closing, compared to the one having a compression coil spring. There is a drawback of becoming. Further, when the operation of the bellows pump is stopped, there is a drawback that the fluid easily flows backward from the discharge passage into the bellows and from the inside of the bellows into the suction passage due to a delay in valve closing. Such a reverse flow of the fluid causes a loss of quantitativeness when the operation of the bellows pump is resumed. In addition, since a space for accommodating the valve body is required in the valve case, there is a limit to reducing the lateral dimension of the valve case.

  The present invention provides a bellows pump that can open and close the check valve with high responsiveness according to the expansion and contraction of the bellows, while enabling the bellows pump to be downsized and maintaining the sealing accuracy of the check valve over a long period of time. Objective.

The bellows pump of the present invention includes a pump head in which a fluid flow path is formed, a bellows attached to the pump head, the inside of which communicates with the flow path, and which can be expanded and contracted in the horizontal direction. A check valve that allows fluid flow to and prevents fluid flow in the other direction,
The check valve is housed in the pump head, and is movable to the valve closing direction by its own weight, and is attached to the pump head, and prevents the valve body from being detached from the pump head. And a cap member.

  According to the present invention, since the valve body of the check valve can move in the valve closing direction by its own weight, the opening / closing operation according to the flow of the fluid accompanying the expansion / contraction of the bellows, in particular, from the opening even without urging by the compression coil spring. The closing operation can be performed quickly, and even when the bellows pump is stopped, the backflow of the fluid can be appropriately prevented. Further, since it is not necessary to provide a compression coil spring and the valve body is accommodated in the pump head, the horizontal dimension of the check valve can be reduced, the size of the bellows pump can be reduced, and the compression can be performed. There is no problem that the sealing accuracy is lowered due to the creep of the coil spring.

  In the pump head, the valve body is movably accommodated, and a moving passage that is inclined with respect to the horizontal direction is formed so that the moving direction of the valve body for closing the valve is low. Is preferred. Thereby, the valve body can be moved by its own weight in the valve closing direction along the movement path.

The valve body may be a sphere that can roll along the movement path, or a cylinder that can roll along the movement path.
In any case, the valve body can be smoothly moved in the moving passage.

  According to the present invention, the check valve can be opened and closed with high responsiveness according to the expansion and contraction of the bellows, while the bellows pump can be downsized and the seal accuracy of the check valve can be maintained over a long period of time.

It is sectional drawing of the bellows pump which concerns on embodiment of this invention. It is sectional drawing which shows a pump head and a check valve. It is a perspective view which shows a pump head and a check valve. (A) is an enlarged front sectional view of the suction passage and the moving passage formed in the pump head, and (b) is an enlarged side view of the suction passage and the moving passage. (A) is an enlarged front sectional view of the discharge passage and the movement passage formed in the pump head, and (b) is an enlarged side view of the discharge passage and the movement passage. (A) is front sectional drawing of the cap member of the check valve for suction, (b) is a side view of the cap member. It is front sectional drawing of the cap member of the check valve for discharge. It is explanatory drawing which shows the effect | action of a bellows pump. It is explanatory drawing which shows the effect | action of a bellows pump.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<Overall configuration of bellows pump>
FIG. 1 is a cross-sectional view of a bellows pump according to an embodiment of the present invention.
The bellows pump 10 of this embodiment is used when supplying a certain amount of transfer fluid such as a chemical solution or a solvent, and a pump head 11 and a pair of pumps attached to both sides of the pump head 11 in the left-right direction (horizontal direction). A case 12, a pair of bellows 13 attached to the side surface in the left-right direction of the pump head 11 inside each pump case 12, and a total of four attached to the side surface in the left-right direction of the pump head 11 inside the pair of bellows 13. Check valves 38 and 40.

<Configuration of pump case>
The pump case 12 has a cylindrical case body 15 fixed to the left and right sides of the pump head 11 and a closing lid that closes one end of the case body 15 in the left-right direction (the end opposite to the pump head 11). 16. A sealing member is interposed on the joint end surface of the case body 15, the pump head 11, and the closing lid 16, and a space surrounded by these members is an air chamber 17 in which an airtight state is maintained.

The closing lid 16 is provided with an intake / exhaust port 19, and the intake / exhaust port 19 is connected to an air supply device (drive device) 20 such as an air compressor via a switching valve 18.
In addition, a detection sensor 21 including a proximity sensor is attached to the closing lid 16, and the detection sensor 21 detects an operation plate 24 attached to the bellows 13 to detect the expansion / contraction state of the bellows 13. .

<Composition of bellows>
The bellows 13 is formed in a bottomed cylindrical shape with a fluororesin such as PTFE or PFA, and the open side end of the bellows 13 is fixed to the pump head 11. Specifically, a circumferential groove 22 is formed at the open end of the bellows 13, and a locking ring 23 protruding inward in the radial direction is fixed between the pump head 11 and the pump case 12. The bellows 13 is fixed to the pump head 11 by fitting the retaining ring 23 into the circumferential groove 22.

  The peripheral wall of the bellows 13 is formed in a bellows shape and configured to be extendable and contractable in the horizontal direction. Further, the outer surface of the bottom portion of the bellows 13 is covered with an operation plate 24. Specifically, a circumferential groove 25 is formed in the outer peripheral portion of the bottom portion of the bellows 13, and the operation plate 24 is fitted by fitting a locking ring 26 fixed to the outer peripheral portion of the operation plate 24 into the peripheral groove 25. Is fixed to the bottom of the bellows 13.

  The operation plate 24 fixed to each of the pair of bellows 13 is connected by an interlocking shaft 28. The interlocking shaft 28 is guided such that a midway portion in the longitudinal direction thereof is slidable in the left-right direction by a guide portion 29 formed in the pump head 11, and both ends thereof are connected to an outer peripheral portion of the operation plate 24 by a nut or the like. It is fixed by the tool 30. The pair of bellows 13 are interlocked by the interlocking shaft 28 so that when one is expanded, the other contracts and when the other contracts, the other expands.

  Air of appropriate pressure generated by the air supply device 20 is alternately supplied to the two air chambers 17 via the intake / exhaust ports 19 provided in the closing lid 16 of each pump case 12. When air is supplied to one air chamber 17, the bellows 13 disposed in the air chamber 17 contracts, and the other bellows 13 expands in conjunction with the contraction of the bellows 13. When the operation plate 24 of the other bellows 13 is detected by the detection sensor 21, the air generated by the air supply device 20 is supplied from the other intake / exhaust port 19 to the other air chamber 17 by the switching valve 18. The As a result, the other bellows 13 contracts and one bellows 13 expands. With the expansion and contraction of the bellows 13, the suction and discharge of the fluid into the bellows 13 are alternately performed, and the fluid can be transferred.

<Configuration of pump head>
FIG. 2 is a sectional view showing the pump head and the check valve, and FIG. 3 is a perspective view showing the pump head and the check valve.
The pump head 11 is made of a fluororesin such as PTFE or PFA. Inside the pump head 11, a suction passage 33 and a discharge passage 34 (the flow path of the present invention) are formed. As shown in FIG. 3, the suction passage 33 and the discharge passage 34 have main passages 33A and 34A that open on the outer peripheral surface of the pump head 11. The main passages 33A and 34A are provided on the outer peripheral surface. The suction port and the discharge port (both not shown) are connected. The suction port is connected to a fluid storage tank or the like, and the discharge port is connected to a fluid transfer destination.

  As shown in FIG. 2, the suction passage 33 and the discharge passage 34 have branch passages 33B and 34B that branch from the main passages 33A and 34A toward the left and right side surfaces of the pump head 11, respectively. , 34B are open on the left and right side surfaces of the pump head 11. The branch passages 33B and 34B communicate with the inside of the bellows 13 via check valves 38 and 40, respectively.

FIG. 4A is an enlarged front sectional view of the suction passage and the moving passage formed in the pump head, and FIG. 4B is an enlarged side view of the suction passage and the moving passage.
The branch passage 33B of the suction passage 33 includes a first branch passage 33B1 that is continuous with the main passage 33A and three second branch passages 33B2 that are recessed in the side surface 11A of the pump head 11. The first branch passage 33 </ b> B <b> 1 is inclined with respect to the horizontal direction so as to become lower as the distance from the side surface 11 </ b> A of the pump head 11 increases. The first branch passage 33B1 communicates with a moving passage 53 that is recessed in the side surface 11A of the pump head 11. The moving passage 53 accommodates the valve body 45 of the check valve 38, and details thereof will be described later.

  The first branch passage 33 </ b> B <b> 1 has a smaller diameter than the movement passage 53, and a tapered portion 66 is formed at a connection portion with the movement passage 53. The tapered portion 66 functions as a valve seat with which the valve body 45 is fitted.

  As shown in FIG. 4B, the three second branch passages 33B2 are equally arranged (triangular arrangement) in the circumferential direction around the movement passage 53 in a side view. Further, as shown in FIG. 4A, the second branch passage 33B2 is recessed in the horizontal direction on the side surface 11A of the pump head 11 at a depth that does not reach the first branch passage 33B1. A part of the three second branch passages 33B2 overlaps and communicates with the movement passage 53, and therefore communicates with the first branch passage 33B1 via the movement passage 53. Therefore, the moving passage 53 also constitutes a part of the suction passage 33.

  Around the second branch passage 33B2 on the side surface 11A of the pump head 11, an annular concave groove 41 for attaching a cap member 44 of the check valve 38 described later is formed. A female screw 42 is formed on the outer peripheral surface of the concave groove 41.

FIG. 5A is a front sectional view of the discharge passage and the movement passage formed in the pump head, and FIG. 5B is a side view of the discharge passage and the movement passage.
Three branch passages 34B of the discharge passage 34 are formed, all of which are recessed from the side surface 11A of the pump head 11 in the horizontal direction and communicate with the main passage 34A. Further, the branch passages 34B are triangularly arranged in a side view as shown in FIG. A moving passage 53 is recessed at the center position of the three branch passages 34 </ b> B arranged in a triangle, and the valve body 45 of the check valve 40 is accommodated in the moving passage 53. Details of the check valve 40 will also be described later.

  Around the branch passage 34 </ b> B on the side surface 11 </ b> A of the pump head 11, an annular concave groove 41 for attaching the cap member 46 of the check valve 40 is formed. A female screw 42 is formed on the outer peripheral surface of the concave groove 41.

《Check valve configuration》
As shown in FIG. 1, on the side surface 11A of the pump head 11, check valves 38 and 40 that allow fluid flow in one direction in the suction passage 33 and discharge passage 34 and prevent fluid flow in the other direction. Is provided.

  The check valve 38 for the suction passage 33 (hereinafter, also referred to as “suction check valve”) opens when the bellows 13 on which the suction passage 33 is arranged expands, and fluid flows into the bellows 13 from the suction passage 33. When the bellows 13 contracts, the valve is closed to prevent the backflow of fluid from the bellows 13 to the suction passage 33.

  Further, the check valve 40 for the discharge passage 34 (hereinafter also referred to as “discharge check valve”) opens when the bellows 13 on which the discharge passage 34 is disposed contracts to the discharge passage 34 from the inside of the bellows 13. Is allowed to flow out and is closed when the bellows 13 is extended to prevent the fluid from flowing backward from the discharge passage 34 into the bellows 13.

As shown in FIG. 2, the suction check valve 38 includes a cap member 44 and a valve body 45.
Fig.6 (a) is front sectional drawing of the cap member of the check valve for suction, (b) is a side view of the cap member. The cap member 44 is formed in a bottomed cylindrical shape from the cylindrical portion 44A and the bottom portion 44B. A male screw 44C is formed on the outer peripheral surface of the cylindrical portion 44A, and this male screw 44C is a female screw 42 of a concave groove 41 formed on the side surface 11A of the pump head 11, as shown in FIGS. Screwed onto. Thereby, the cap member 44 is attached to the pump head 11. Further, the bottom portion 44 </ b> B of the cap member 44 attached to the pump head 11 is disposed at a distance from the side surface 11 </ b> A of the pump head 11.

  As shown in FIG. 6, four communication holes 44 </ b> D are formed in the bottom 44 </ b> B of the cap member 44. The communication hole 44 </ b> D has a function of communicating the suction passage 33 and the inside of the bellows 13.

As shown in FIGS. 2 and 4, the valve body 45 is composed of a sphere (ball), and is disposed in a moving passage 53 formed overlapping the first and second branch passages 33 </ b> B <b> 1 and 33 </ b> B <b> 2 of the suction passage 33. ing.
The movement passage 53 is inclined at substantially the same inclination angle as the first branch passage 33B1 of the suction passage 33. That is, the moving passage 53 is inclined with respect to the horizontal direction so as to become lower as the distance from the side surface 11A of the pump head 11 increases. Therefore, the valve element 34 arranged in the moving passage 53 rolls to the lower side along the inclination in a state where it does not receive pressure from the fluid, and is formed at the boundary between the first branch passage 33B1 and the moving passage 53. The valve seat 66 is fitted. That is, the valve body 45 moves in the closing direction of the suction check valve 38 by its own weight. Further, the valve body 45 is prevented from being separated from the moving passage 53 by the cap member 44.

As shown in FIG. 2, the discharge check valve 40 includes a cap member 46 and a valve body 45.
FIG. 7 is a front sectional view of the cap member of the discharge check valve. The cap member 46 is formed in a bottomed cylindrical shape from the cylindrical portion 46A and the bottom portion 46B. Further, a male screw 46C is formed on the outer peripheral surface of the cylindrical portion 46A, and this male screw 46C is a female screw of a concave groove 41 formed on the side surface 11A of the pump head 11 as shown in FIGS. 42 is screwed. Thereby, the cap member 46 is attached to the pump head 11. Further, the bottom portion 46 </ b> B of the cap member 46 attached to the pump head 11 is substantially in close contact with the side surface 11 </ b> A of the pump head 11.

  One communication hole 46 </ b> D is formed at the center of the bottom 46 </ b> B of the cap member 46. The communication hole 46 </ b> D has a function of communicating the discharge passage 34 and the inside of the bellows 13. A tapered portion 67 is formed around the communication hole 46D on the inner surface of the bottom portion 46B. The tapered portion 67 functions as a valve seat with which the valve body 45 is fitted.

As shown in FIGS. 2 and 5, the valve body 45 is composed of a sphere (ball) similar to the valve body 45 of the suction check valve 38, and is formed to overlap the branch passage 34 </ b> B of the discharge passage 34. It is disposed in the passage 53. The moving passage 53 is inclined with respect to the horizontal direction so as to become lower as it approaches the side surface 11A of the pump head 11. Therefore, the valve body 34 disposed in the moving passage 53 rolls to the lower side along the inclination in a state where the pressure from the fluid is not received, and is fitted to the valve seat 67 formed in the cap member 46. . That is, the valve body 45 moves in the closing direction of the discharge check valve 38 by its own weight. Further, the valve body 45 is prevented from being separated from the moving passage 53 by the cap member 46.
FIG. 2 shows the check valves 38 and 40 that are all closed.

<Operation of bellows pump>
Next, the operation of the bellows pump 10 of this embodiment will be described with reference to FIGS. In addition, in FIG.8 and FIG.9, the structure of the bellows 13 is simplified and shown.
As shown in FIG. 8, when the left bellows 13 contracts and the right bellows 13 expands, the valve bodies 45 of the discharge check valve 40 and the suction check valve 38 mounted on the left side surface of the pump head 11. Receives pressure from the fluid in the left bellows 13 and moves to the right in the movement passage 53. As a result, the discharge check valve 40 is opened, the suction check valve 38 is closed, and the fluid in the left bellows 13 is discharged from the discharge passage 34 to the outside of the pump.

  The valve bodies 45 of the discharge check valve 40 and the suction check valve 38 mounted on the right side surface of the pump head 11 move to the right side in the movement passage 53 by the suction action by the right bellows 13. As a result, the suction check valve 38 is opened, the discharge check valve 40 is closed, and the fluid is sucked into the right bellows 13 from the suction passage 33.

  Next, as shown in FIG. 9, when the right bellows 13 contracts and the left bellows 13 expands, each of the discharge check valve 40 and the suction check valve 38 mounted on the right side surface of the pump head 11. The valve body 45 receives pressure from the fluid in the right bellows 13 and moves to the left in the movement passage 53. As a result, the discharge check valve 40 is opened, the suction check valve 38 is closed, and the fluid in the right bellows 13 is discharged from the discharge passage 34 to the outside of the pump.

  The valve bodies 45 of the discharge check valve 40 and the suction check valve 38 mounted on the left side surface of the pump head 11 move to the left in the movement passage 53 by the suction action of the left bellows 13. As a result, the suction check valve 38 is opened, the discharge check valve 40 is closed, and the fluid is sucked into the left bellows 13 from the suction passage 33.

  By repeating the above operation, the left and right bellows 13 alternately suck and discharge the fluid, and can transfer a fluid having a capacity defined by the volume of the bellows 13 and the number of strokes.

<< Effects of this embodiment >>
In the present embodiment, the valve body 45 of the check valves 38 and 40 is configured to move in the direction of closing the check valve (valve closing direction) by its own weight along the inclination of the movement passage 53. Therefore, the flow of the fluid according to the expansion and contraction of the bellows 13 can be followed with good responsiveness, and in particular, the operation from opening to closing can be performed quickly. For this reason, it is possible to prevent the back flow of the fluid due to the delay in closing the valve. Therefore, when the operation of the bellows pump 10 is stopped, the backflow of the fluid from the discharge passage 34 into the bellows 13 and the backflow of the fluid from the inside of the bellows 13 to the suction passage 33 can be suitably suppressed. Thereby, the quantitative property when the operation of the bellows pump 10 is resumed can be reliably ensured.

  In addition, since the check valves 38 and 40 of the present embodiment do not use a compression coil spring as in the prior art, the sealing accuracy is not reduced due to creep of the compression coil spring. Further, since the compression coil spring is not used, it is not necessary to secure an expansion / contraction stroke of the compression coil spring, and the check valves 38 and 40 can be formed short in the left-right direction.

  In the present embodiment, since the moving passage for accommodating the valve body 45 of the check valves 38 and 40 is formed in the pump head 11 instead of the check valves 38 and 40 themselves, the check valves 38 and 40 are moved in the left-right direction. It can be formed short.

  If the check valves 38, 40 are shortened in the left-right direction, the bottom of the bellows 13 and the check valves 38, 40 may interfere even if the bellows 13 is shortened in the left-right direction (the number of bellows peaks of the bellows 13 is reduced). Therefore, the bellows pump 10 can be downsized. In addition, by making the bellows 13 short, a more inexpensive bellows pump 10 can be obtained.

Since the check valves 38 and 40 are composed of two parts of the valve body 45 and the cap members 44 and 46, the check valves 38 and 40 can be configured with a small number of parts at low cost.
Further, when the moving passage inclined with respect to the check valves 38 and 40 is formed, the check valves 38 and 40 must be attached to the pump head 11 while accurately adjusting the inclination direction of the moving passage. Then, the check valves 38 and 40 can be easily attached to the pump head 11 without being aware of the inclination direction of the moving passage. Therefore, the assembly property of the bellows pump 10 can be improved.

  By reducing the number of parts of the check valves 38 and 40 and improving the assemblability of the bellows pump 10 as described above, the amount of material used, processing costs, and assembly man-hours can be reduced, and the manufacturing cost of the bellows pump 10 can be reduced as a whole. It becomes.

Further, in the present embodiment, since the valve body 45 is constituted by a spherical body, the movement in the movement passage 53, particularly the movement due to its own weight, is smoothly performed, and the responsiveness to the flow of fluid according to the expansion and contraction of the bellows 13 is further improved. Can be increased.
The valve body 45 is not limited to a spherical body, but may be configured in other forms as long as it can move along the inclination of the movement passage 53. For example, the valve body 45 can be comprised by a cylindrical body (column body).

  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.

10: Bellows pump 11: Pump head 13: Bellows 33: Suction passage (flow path)
34: Discharge passage (flow path)
38: Check valve for suction 40: Check valve for discharge 44: Cap member 45: Valve element 46: Cap member 53: Movement passage

Claims (4)

A pump head in which a fluid flow path is formed, a bellows which is attached to the pump head and communicates with the flow path in the horizontal direction, and allows fluid flow in one direction with respect to the flow path. And a check valve for preventing fluid flow in the other direction,
The check valve is housed in the pump head, and is movable to the valve closing direction by its own weight, and is attached to the pump head, and prevents the valve body from being detached from the pump head. A bellows pump.   In the pump head, the valve body is movably accommodated, and a moving passage inclined with respect to the horizontal direction is formed so that the moving direction of the valve body for closing the valve is low. Item 2. A bellows pump according to item 1.   The bellows pump according to claim 2, wherein the valve body is a spherical body that can roll along the moving passage.   The bellows pump according to claim 2, wherein the valve body is a cylindrical body that can roll along the moving passage.

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