JP2015113786A - Bellows pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bellows pump capable of increasing a discharge amount per unit time while preventing damage of a bellows.SOLUTION: A bellows pump includes an air cylinder part 30 having a first air cylinder 31. The first air cylinder includes a first piston 35 connected to an extension and contraction direction one end 13 of the bellows, a first cylinder 36, and two air chambers 37 and 38, and by supplying and discharging compressed air to and from the two air chambers, the first piston can be reciprocated so as to expand and contract the bellows.

Description

  The present invention relates to a bellows pump.

  In a semiconductor or liquid crystal manufacturing facility or the like, a bellows pump is used to flow a fluid such as ultrapure water or a chemical solution. This type of bellows pump generally includes a pump body, a bellows, and a drive device (see, for example, Patent Document 1).

  The pump body has a suction flow path for sucking fluid and a discharge flow path for discharging fluid. The bellows is provided in the pump body, and is configured to be extendable and retractable in order to suck fluid from the suction channel and discharge the fluid to the discharge channel. The drive device is for expanding and contracting the bellows, and has one air cylinder for one bellows.

  The internal space of the pump body is partitioned by the bellows into a fluid chamber inside the bellows where fluid can be stored and an air chamber outside the bellows where compressed air is supplied and discharged. The bellows expands and contracts to suck and discharge fluid by supplying and discharging compressed air to and from the air chamber of the pump body and the air chamber of the air cylinder.

  In such a bellows pump, when it is desired to increase the discharge amount per unit time, the volume in the bellows (the amount that can be discharged in one expansion stroke) does not change, so the number of expansion / contraction strokes of the bellows per unit time is set. increase. As the means, means for increasing the pressure applied to the bellows by increasing the compressed air supply pressure to the air chamber of the pump body is taken.

  However, if this measure is taken, the pressure difference between the air chamber and the fluid chamber in the pump body increases, and the bellows may be damaged due to the pressure difference. In consideration of the above, it was necessary to set the compressed air supply pressure to the air chamber. Accordingly, there is a great limitation on the pressure applied to the bellows, that is, the number of expansion / contraction strokes per unit time of the bellows, and the discharge amount per unit time cannot be increased sufficiently.

JP-A-10-196521

  This invention is made | formed in view of such a situation, and it aims at provision of the bellows pump which can aim at the increase in the discharge amount per unit time, preventing the damage of a bellows.

  According to a first aspect of the present invention, there is provided a suction passage for sucking a fluid, a pump body having a discharge passage for discharging the fluid, and a pump body provided in the pump body, the fluid being supplied to the suction passage. A bellows pump comprising: a bellows configured to be stretchable so as to be sucked from and discharged to the discharge flow path; and an air cylinder portion for causing the bellows to expand and contract, wherein the air cylinder portion is configured to expand and contract the bellows. A first piston coupled to one end of the direction via a first coupling member, a first cylinder that slidably accommodates the first piston, and two airs that sandwich the first piston in the first cylinder And at least one first piston capable of reciprocating the first piston so as to expand and contract the bellows by supplying and discharging compressed air to and from the two air chambers. It is those with a Ashirinda.

  The invention according to claim 2 is the bellows pump according to claim 1, wherein the air cylinder portion is directly or indirectly connected to a first piston of the at least one first air cylinder via a second connecting member. The second piston, a second cylinder that slidably accommodates the second piston, and two air chambers that sandwich the second piston in the second cylinder. It is provided with at least one second air cylinder that can reciprocate the second piston in synchronization with the first piston by supplying and discharging compressed air.

  According to a third aspect of the present invention, in the bellows pump according to the first or second aspect, the internal space of the pump body has a fluid chamber in the bellows capable of storing fluid by the bellows, and compressed air. When the bellows is contracted by driving the first air cylinder and the second air cylinder, the compressed air is supplied to the air chamber of the pump body. It is comprised so that.

  ADVANTAGE OF THE INVENTION According to this invention, the bellows pump which can aim at the increase in the discharge amount per unit time can be provided, preventing the damage of a bellows.

It is sectional drawing of the bellows pump which concerns on one Embodiment of this invention. It is a schematic sectional drawing of the air cylinder part in the bellows pump of FIG. (A) It is a figure which shows the relationship between the discharge pressure of the bellows pump of FIG. 1, the expansion-contraction operation | movement of the bellows of the said bellows pump, and time. (B) It is a figure which shows the relationship between the discharge pressure of the bellows pump using only one air cylinder, the expansion-contraction operation | movement of the bellows of the said bellows pump, and time. It is a schematic sectional drawing of the air cylinder part in the bellows pump which concerns on other embodiment of this invention.

  A preferred embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a bellows pump 1 according to an embodiment of the present invention includes a pump unit 2 and a pulsation suppressing unit 3 provided alongside the pump unit 2. The pump unit 2 and the pulsation suppressing unit 3 have a common partition wall 5 and are arranged coaxially with each other. The partition wall 5 is formed with a suction flow path 6 for sucking fluid, a discharge flow path 7 for discharging fluid, and an intermediate flow path 8.

  The pump unit 2 includes a bellows 10. The bellows 10 is provided in the pump body 4 to suck fluid from the suction flow path 6 and to the discharge flow path 7 (in the present embodiment, the discharge flow path via the intermediate flow path 8). 7) It is configured to be extendable in the axial direction (left-right direction in FIG. 1) for discharging.

  In the present embodiment, the pump body 4 includes the partition wall 5 and a bottomed cylindrical pump casing 11 attached to a side wall portion on one side in the axial direction (right side in FIG. 1) of the partition wall 5; It is constituted by a bottomed cylindrical casing 71 attached to the side wall portion on the other side in the axial direction of the partition wall 5 (left side in FIG. 1).

  In the pump body 4, the bellows 10 is disposed in an internal space of the pump casing 11 formed by being surrounded by the partition wall 5 and the pump casing 11. The bellows 10 has an opening peripheral edge 12 on the other side in the axial center direction, and the opening peripheral edge 12 is fixed to the pump body 4 by being joined between the partition wall 5 and the pump casing 11. ing.

  The bellows 10 has a closed end 13 on one side in the axial direction, and is provided so as to protrude from the partition wall 5 toward the bottom wall 16 of the pump casing 11. Thereby, using the bellows 10, the internal space of the pump casing 11 is hermetically partitioned into a fluid chamber 14 located in the bellows 10 and an air chamber 15 located outside the bellows 10. .

  The bellows 10 has a cylindrical bellows portion 18 between the opening peripheral edge portion 12 and the closed end portion 13, and moves the closed end portion 13 in the internal space of the pump casing 11. The axial direction of the pump casing 11 can be expanded and contracted. Here, the bellows 10 is made of a fluororesin such as polytetrafluoroethylene (PTFE).

  In the pump unit 2, a fluid suction port 21 and a discharge port 22 communicate with the fluid chamber 14. The suction port 21 communicates with the suction flow path 6, and the discharge port 22 communicates with the intermediate flow path 8. A suction-side check valve 23 and a discharge-side check valve 24 that can be alternately opened and closed as the bellows 10 expands and contracts are provided in the middle of the suction flow path 6 and the intermediate flow path 8. ing.

  The suction side check valve 23 is configured to allow only the flow of fluid from the suction flow path 6 into the bellows 10. That is, the suction-side check valve 23 allows the suction of fluid from the suction passage 6 toward the fluid chamber 14 and prevents the backflow of fluid from the fluid chamber 14 toward the suction passage 6. Configured to get.

  The discharge-side check valve 24 is configured to allow only a fluid flow from the bellows 10 toward the intermediate flow path 8 serving as a discharge flow path. That is, the discharge-side check valve 24 allows the discharge of fluid from the fluid chamber 14 toward the intermediate flow path 8 and prevents the reverse flow of fluid from the intermediate flow path 8 toward the fluid chamber 14. Configured to get.

  Further, a movable body 26 is provided in the pump casing 11 so as to be connected to the bellows 10 so as to be able to move the bellows 10 to extend and contract. The movable body 26 is fixed to the closed end portion 13 of the bellows 10. The bellows pump 1 is provided with a drive device including an air cylinder portion 30 for expanding and contracting the bellows 10.

  The drive device includes a compressed air supply device such as a compressor (not shown) in addition to the air cylinder portion 30. The air cylinder part 30 has one or a plurality of air cylinders. That is, as shown in FIG. 2, the air cylinder portion 30 has at least one (one in the present embodiment) first air cylinder 31.

  The first air cylinder 31 includes a first piston 35 connected to one end of the bellows 10 in the expansion / contraction direction (the closed end 13) via the movable body 26 and a first connecting member 34, and the first piston. The first cylinder 36 slidably accommodates 35 and the two air chambers 37 and 38 sandwiching the first piston 35 in the first cylinder 36.

  The first air cylinder 31 can reciprocate the first piston 35 so that the bellows 10 can be expanded and contracted by supplying and discharging compressed air to and from the two air chambers 37 and 38. Has been. In the present embodiment, the first air cylinder 31 is provided outside the bottom wall portion 16 of the pump casing 11.

  In the first air cylinder 31, the first connecting member 34 is formed in a shaft shape and is provided so as to slidably penetrate the bottom wall portion 16 of the pump casing 11. The first piston 35 is connected to the movable body 26 via the first connecting member 34. The first cylinder 36 is connected to the bottom wall portion 16 of the pump casing 11 and is fitted to the first piston 35 so that the first piston 35 can slide in the direction of expansion and contraction (axial center) of the bellows 10. .

  The internal space of the first cylinder 36 is partitioned by the first piston 35 into the two air chambers 37 and 38 with respect to the expansion / contraction direction of the bellows 10. The two air chambers 37 and 38 are an extension side air chamber 37 located on the other side of the bellows 10 in the extension / contraction direction and a contraction side air chamber 38 located on one side of the bellows 10 in the extension / contraction direction, respectively. Compressed air is supplied and discharged through air holes 41 and 42 formed in the cylinder 36.

  Preferably, as in the present embodiment, the air cylinder portion 30 includes at least one (two in the present embodiment) second air cylinders 32A and 32B.

  The second air cylinders 32A and 32B include second pistons 45A and 45B that are directly or indirectly coupled to the first piston 35 of the first air cylinder 31 via second coupling members 44A and 44B, respectively. Two cylinders 46A and 46B that slidably accommodate two pistons 45A and 45B, and two air chambers 47A and 48A, 47B and 48B that sandwich the second pistons 45A and 45B in the second cylinders 46A and 46B, have.

  The second air cylinders 32A and 32B are supplied to and discharged from the two air chambers 47A and 48A, 47B and 48B, so that the second pistons 45A and 32B are synchronized with the first piston 35. 45B can be reciprocated. In the present embodiment, one second air cylinder 32A of the second air cylinders 32A and 32B is disposed on one side in the axial direction of the first air cylinder 31 (the right side in FIG. 2). 1 The air cylinder 31 and the same axis are connected in series.

  In the one second air cylinder 32A, the second connecting member 44A is formed in a shaft shape and slidably penetrates the connecting portion with the first air cylinder 31. The second piston 45A is connected to the first piston 35 via the second connecting member 44A. The second cylinder 46A is fitted with the second piston 45A so that the second piston 45A can slide in the expansion / contraction direction of the bellows 10.

  The internal space of the one second air cylinder 32A is partitioned into the two air chambers 47A and 48A with respect to the expansion and contraction direction of the bellows 10 by the second piston 45A. The two air chambers 47A and 48A are an extension side air chamber 47A located on the other side in the expansion / contraction direction of the bellows 10 and a contraction side air chamber 48A located on one side in the expansion / contraction direction of the bellows 10, respectively. Compressed air is supplied and discharged through air holes 51A and 52A formed in the cylinder 46A.

  Further, in the present embodiment, the other second air cylinder 32B of the second air cylinders 32A and 32B is arranged on one side in the axial direction of the one second air cylinder 32A (the right side in FIG. 2). Thus, the second air cylinder 32A is connected in series on the same axis.

  In the other second air cylinder 32B, the second connecting member 44B is formed in a shaft shape so as to slidably penetrate the connecting portion with the second air cylinder 32A. The second piston 45B is connected to the second piston 45A of the one second air cylinder 32A via the second connecting member 44B. The second cylinder 46B is fitted with the second piston 45B so that the second piston 45B can slide in the expansion and contraction direction of the bellows 10.

  The internal space of the other second air cylinder 32B is partitioned into the two air chambers 47B and 48B with respect to the expansion and contraction direction of the bellows 10 by the second piston 45B. The two air chambers 47B and 48B are an extension side air chamber 47B located on the other side of the bellows 10 in the extension direction and a contraction side air chamber 48B located on one side of the bellows 10 in the extension direction. Compressed air is supplied and discharged through air holes 51B and 52B formed in 46B.

  The compressed air supply device can alternately supply compressed air to the extension side air chamber 37 and the contraction side air chamber 38 through the air hole 41 or the air hole 42 of the first air cylinder 31. It is configured as follows. The compressed air supply device further supplies compressed air to the extended air chambers 47A and 47B of the second air cylinders 32A and 32B simultaneously when supplying compressed air to the extended air chamber 37 of the first air cylinder 31. In addition, when compressed air is supplied to the contraction-side air chamber 38 of the first air cylinder 31, the compressed air is supplied to the contraction-side air chambers 48A and 48B of the second air cylinders 32A and 32B simultaneously.

  Here, proximity sensors 55 and 56 are respectively attached to the first cylinder 36 of the first air cylinder 31 and the bottom wall portion 16 of the pump casing 11. The first piston 35 and the movable body 26 of the first air cylinder 31 alternately approach the proximity sensors 55 and 56 as the first piston 35 reciprocates (the expansion and contraction operation of the bellows 10). Thus, the supply destination of the compressed air supplied from the compressed air supply device is automatically switched between the expansion side air chambers 37, 47A and 47B and the contraction side air chambers 38, 48A and 48B. It is configured as follows.

  Further, as shown in FIG. 1, the pulsation suppressing unit 3 includes a bellows 70. The bellows 70 sucks fluid from a suction channel (in the present embodiment, the intermediate channel 8 functioning as a suction channel) and discharges the fluid to the discharge channel 7 in the axial direction (see FIG. 1 in the left-right direction).

  In the present embodiment, the bellows 70 is disposed in an internal space of the casing 71 formed by being surrounded by the partition wall 5 and the casing 71. The bellows 70 has an opening peripheral edge 72 on one side in the axial direction, and the opening peripheral edge 72 is fixed to the pump body 4 by being joined between the partition wall 5 and the casing 71. .

  The bellows 70 has a closed end 73 on the other side in the axial direction, and is provided so as to protrude from the partition wall 5 toward the bottom wall of the casing 71. Accordingly, the internal space of the casing 71 is partitioned in a sealed manner using the bellows 70 into a fluid chamber 74 located in the bellows 70 and a gas chamber 75 located outside the bellows 70.

  The bellows 70 has a cylindrical bellows portion 78 between the opening peripheral edge portion 72 and the closed end portion 73, and moves the closed end portion 73 in the internal space of the casing 71. The casing 71 can be expanded and contracted with the axial direction of the casing 71 as the expansion and contraction direction. Here, the bellows 70 is made of a fluororesin such as PTFE.

  Further, in the pulsation suppressing unit 3, the intermediate flow path 8 and the discharge flow path 7 are communicated with the fluid chamber 74. At a position facing the closed end portion 73 of the bellows 70, a stopper wall 81 for restricting excessive extension that may occur due to an unexpected situation of the bellows 70 has a predetermined interval with respect to the closed end portion 73. They are spaced apart.

  The casing 71 is provided with an automatic air supply / exhaust adjustment device 82. The automatic air supply / exhaust adjustment device 82 can balance the fluid pressure in the fluid chamber 74 and the atmospheric pressure (enclosed pressure) in the gas chamber 75 in order to prevent excessive expansion and deformation of the bellows 70. It is configured.

  Specifically, when the capacity of the fluid chamber 74 increases beyond a predetermined range, the automatic air supply / exhaust adjustment device 82 sucks into the gas chamber 75 to increase the pressure of the gas chamber 75, and When the capacity of 74 decreases beyond a predetermined range, the sealed pressure is lowered by exhausting from the gas chamber 75.

  Next, the operation of the bellows pump 1 will be described.

  In the pump unit 2, the compressed air from the compressed air supply device flows into the extension side air chamber 37 of the first air cylinder 31 and the extension side air chambers 47 A and 47 B of the second air cylinders 32 A and 32 B. Supplied at the same time. By this supply, the first piston 35 and the second pistons 45A and 45B move forward in one axial direction, and the bellows 10 extends in the right direction in FIG. Therefore, the fluid chamber 14 becomes negative pressure and the discharge side check valve 24 is closed, while the suction side check valve 23 is opened and the fluid from the suction flow path 6 is in the open position. The fluid is sucked into the fluid chamber 14 through the side check valve 23 (suction process).

  Thereafter, the compressed air from the compressed air supply device changes the supply destination, the contraction side air chamber 38 of the first air cylinder 31, and the contraction side air chambers 48A and 48B of the second air cylinders 32A and 32B. Are supplied at the same time. By this supply, the first piston 35 and the second pistons 45A and 45B are moved back to the other side in the axial direction, and the bellows 10 is contracted leftward in FIG. Therefore, while the suction side check valve 23 is closed, the discharge side check valve 24 is opened, and the discharge side check valve 24 in which the fluid sucked and stored in the fluid chamber 14 is in the open position is provided. Then, the ink is discharged toward the intermediate flow path 8 (the discharge passage 7) (discharge process).

  When the bellows pump 1 is driven, such a suction process and a discharge process are repeated in the pump unit 2. Thereby, a predetermined pump operation of the pump unit 2 is executed.

  Further, in the present embodiment, the fluid discharged from the discharge port 22 of the pump unit 2 becomes a pulsating flow due to the expansion / contraction operation of the pump unit 2, and the pulsation suppression is performed via the intermediate flow path 8. It is fed into the fluid chamber 74 formed inside the bellows 70 of the section 3. Then, after the fluid is temporarily stored in the fluid chamber 74, the fluid is transferred from the discharge flow path 7 to the outside of the pulsation suppressing unit 3 (the bellows pump 1).

  At this time, when the discharge pressure of the fluid from the pump unit 2 tends to increase, the bellows 70 extends in the pulsation suppressing unit 3 to increase the capacity of the fluid chamber 74 and absorb the discharge pressure. To do. Therefore, the amount of fluid transferred from the fluid chamber 74 to the outside of the pulsation suppressing unit 3 is smaller than the amount discharged from the pump unit 2 toward the pulsation suppressing unit 3.

  If the discharge pressure of the fluid starts to decrease in this state, the fluid pressure becomes lower than the enclosed pressure in the gas chamber 75 compressed by the expansion of the bellows 70, so the bellows 70 contracts and the The capacity of the fluid chamber 74 is reduced. Therefore, the amount of fluid transferred from the fluid chamber 74 to the outside of the pulsation suppressing unit 3 is larger than the amount discharged from the pump unit 2 toward the pulsation suppressing unit 3.

  The fluid is transferred from the pulsation suppressing unit 3 to the outside while the pulsation is attenuated by the repeated operation of the capacity change of the fluid chamber 74 accompanying the expansion and contraction operation of the bellows 70. Thereby, in the bellows pump 1, the fluid is continuously and smoothly discharged from the bellows pump 1 toward the outside.

  In addition, in the present embodiment, at least one air cylinder (that is, the first air cylinder 31, preferably the second air cylinder 32A. The bellows 10 is expanded and contracted using a material having 32B added thereto. Therefore, as shown in FIGS. 3A and 3B, when using one air cylinder, the time t1 required to increase the discharge pressure of the bellows pump 1 to a predetermined value P in the compression process of the bellows 10 is used. It is possible to shorten the change time from the most extended state to the most contracted state of the bellows 10 (T2 → T1). Therefore, the discharge amount per unit time can be increased by increasing the number of expansion / contraction strokes per unit time of the bellows 10.

  In addition, at this time, the compressed air of a predetermined pressure is alternately supplied to the two air chambers 37, 38, 47A, 48A, 47B, 48B in the air cylinder portion 30, thereby the first air cylinder 31 and the Since the second air cylinders 32 </ b> A and 32 </ b> B are driven, and the bellows 10 is expanded and contracted, the damage of the bellows 10 due to the differential pressure between the air chamber 15 and the fluid chamber 14 in the pump body 4 is taken into consideration. There is no need to do. Therefore, according to the bellows pump 1, it is possible to increase the discharge amount per unit time while preventing the bellows 10 from being damaged.

  Moreover, in this embodiment, the internal space of the pump body 4 (the pump casing) has the fluid chamber 14 in which fluid can be stored by the bellows 10, and the air chamber 15 to which compressed air is supplied and discharged. It is divided into. When the bellows 10 is contracted by driving the first air cylinder 31 and the second air cylinders 32 </ b> A and 32 </ b> B, air formed in the bottom wall portion 16 in the air chamber 15 of the pump body 4. The compressed air from the compressed air supply device is supplied through the hole 58.

  With such a configuration, it is possible to further shorten the time required to increase the pressure necessary for the contraction of the bellows 10 and shorten the change time of the bellows 10 from the most expanded state to the most contracted state. Therefore, in the bellows pump 1, it becomes easy to increase the discharge amount per unit time more effectively. Of course, in this case, the compressed air supply pressure to the air chamber 15 is appropriately set so that the bellows 10 is not damaged due to the differential pressure between the air chamber 15 and the fluid chamber 14.

  In the present embodiment, the air cylinder portion according to the present invention includes the first air cylinder 31 and the second air cylinders 32A and 32B connected in series to the first air cylinder 31. However, the present invention is not limited to this. For example, as shown in FIG. 4, a plurality of first air cylinders 31 and a plurality of first air cylinders 31 individually connected to the first air cylinders 31 and arranged in parallel with each other. The air cylinder part 30 having the second air cylinders 32A, 32B, and 32C may be used.

DESCRIPTION OF SYMBOLS 1 Bellows pump 4 Pump body 6 Suction flow path 7 Discharge flow path 10 Bellows 14 Fluid chamber 15 Air chamber 30 Air cylinder part 31 1st air cylinder 32A * 32B * 32C 2nd air cylinder 34 1st connection member 35 1st piston 36 First cylinder 37 Air chamber 38 Air chamber 44A / 44B / 44C Second connecting member 45A / 45B / 45C Second piston 46A / 46B / 46C Second cylinder 47A / 47B / 47C Air chamber 48A / 48B / 48C Air chamber 51A / 51B / 51C Air hole 52A / 52B / 52C Air hole 58 Air hole

Claims (3)

A pump body having a suction flow path for sucking fluid and a discharge flow path for discharging fluid; and a pump body provided in the pump body for sucking fluid from the suction flow path and the discharge flow path In a bellows pump comprising a bellows configured to be extendable and retractable for discharging to an air cylinder portion for extending and contracting the bellows,
The air cylinder part is
A first piston coupled to one end of the bellows in the expansion / contraction direction via a first coupling member, a first cylinder that slidably accommodates the first piston, and the first piston in the first cylinder. And at least one first air cylinder that can reciprocate the first piston so that the bellows can be expanded and contracted by supplying and discharging compressed air to and from the two air chambers. A bellows pump comprising: The air cylinder part is
A second piston coupled directly or indirectly to a first piston of the at least one first air cylinder via a second coupling member; a second cylinder that slidably accommodates the second piston; Two air chambers sandwiching the second piston in the second cylinder, and the compressed air is supplied to and discharged from the two air chambers so that the second piston reciprocates in synchronization with the first piston. The bellows pump according to claim 1, further comprising at least one second air cylinder that can be moved. The internal space of the pump body is partitioned by the bellows into a fluid chamber in the bellows where fluid can be stored and an air chamber outside the bellows to which compressed air is supplied and discharged,
The compressed air is supplied to the air chamber of the pump body when the bellows is contracted by driving the first air cylinder and the second air cylinder. Or the bellows pump of Claim 2.

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