JP7169893B2 - rolling diaphragm pump - Google Patents

Description

TECHNICAL FIELD The present invention relates to rolling diaphragm pumps, and more particularly to the structure of the pump head.

A rolling diaphragm pump is a pump that changes the volume in a pump chamber by deforming a rolling diaphragm, and has the advantage of being able to maintain a constant discharge rate with high accuracy. Furthermore, the rolling diaphragm pump can be made of fluorine resin for the entire pump chamber, including the rolling diaphragm. As a result, rolling diaphragm pumps are often used to transport fluids that do not want to come into contact with metal or rubber. Typical uses of rolling diaphragm pumps include application or preparation of chemical solutions such as pure water or solvents in the manufacturing processes of semiconductors, liquid crystals, organic ELs, solar cells, and the like.

As a rolling diaphragm pump drive mechanism, for example, an electric type disclosed in Patent Documents 1 to 3 is known. In this method, a motor reciprocates the piston. As the piston moves, a rolling diaphragm connected to it is displaced to change the volume of the pump chamber.

JP 2015-098855 A JP 2016-061169 A Japanese Patent Application Laid-Open No. 2018-003712

In semiconductor processes, it is extremely important to prevent contamination of the wafer surface by impurities. Impurities include, for example, fine particles (particles), metals, and organic substances. In order to prevent contaminants from contaminating the wafer surface, rolling diaphragm pumps must undergo flushing during regular maintenance. Flushing means circulating a cleaning liquid or pure water through a pump to wash the inside of the pump chamber, and then sending a gas such as nitrogen gas or an inert gas into the pump chamber to dry the inside of the pump chamber. Since there is generally a liquid pool in the pump chamber, residual chemical liquid or pure water (hereinafter abbreviated as chemical liquid or the like) must be forcibly removed by flushing. A liquid pool is a gap in the wetted part of the pump in which the liquid remains even when the piston moves to the position where the volume of the pump chamber becomes the smallest. Liquid puddles include, for example, the gap between the rolling diaphragm and the pump chamber, and the gaps in the joints located at the inlet and outlet, respectively. When the pump stops, the chemical solution or the like generally remains in the liquid pool. As water evaporates from these residual liquids, the solute solidifies into particles. There is a risk that these particles will sometimes mix into the chemical liquid from the liquid pool and reach the wafer surface. The primary role of flushing is to remove these particles from the pool.

In order to reliably prevent contamination of the chemical solution by particles and maintain high reliability of the pump, flushing must be repeated before particles grow in the liquid pool. However, the task of removing the residual liquid from the liquid pool by flushing is time-consuming and labor-intensive, which imposes a heavy burden on the user of the pump.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and in particular, by increasing the certainty that residual liquid is removed from a liquid pool by flushing, the user's burden of maintenance can be reduced while maintaining high reliability. To provide a rolling diaphragm pump that can be lightened.

A rolling diaphragm pump in one aspect of the present invention comprises a head including an inlet and a outlet, a cylinder closed at one end by the head, a partition between the head and the cylinder and in the head, the inlet and the outlet. A displaceable member defining a pumping chamber in communication with an outlet and capable of reciprocating movement within a rolling diaphragm and cylinder whose displacement causes fluid to move from the inlet to the pumping chamber or from the pumping chamber to the outlet. A cylindrical member connected to the rolling diaphragm in the piston that displaces the rolling diaphragm by reciprocating motion, and the inner surface of the side wall of the head and the rolling diaphragm that occurs when the piston moves until the distance from the head to the piston reaches the lower allowable limit. and a tube extending from at least one of the inlet and outlet through the gap between the inlet and outlet.

The tube may be integrally molded with the head. The head may include fittings provided at the inlet and outlet. These fittings may be molded integrally with the head.

In the above rolling diaphragm pump according to the present invention, a tube extends from at least one of the suction port and the discharge port through the gap between the inner surface of the side wall of the head and the rolling diaphragm. During flushing, the chemical liquid remaining in the liquid pool is discharged through this pipe. It is easy to place the tip of this tube as far away from the puddle as possible. Thus, this rolling diaphragm pump can increase the certainty that residual liquid will be removed from the liquid pool by flushing. As a result, this pump can reduce the user's burden of maintenance while maintaining high reliability.

1 is a perspective view showing the appearance of a rolling diaphragm pump according to an embodiment of the present invention; FIG. FIG. 2 is a longitudinal cross-sectional view along line II-II shown in FIG. 1; The distance from the head to the piston is the upper allowable limit. FIG. 2 is a longitudinal cross-sectional view along line II-II shown in FIG. 1; The distance from the head to the piston is the lower allowable limit. FIG. 2 is a longitudinal cross-sectional view along line II-II shown in FIG. 1; The piston is at its highest point. FIG. 4 is a vertical cross-sectional view of a rolling diaphragm pump according to a modification of the embodiment of the invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Structure of rolling diaphragm pump]

FIG. 1 is a perspective view showing the appearance of a rolling diaphragm pump (hereinafter simply referred to as "pump") according to an embodiment of the present invention, and FIGS. FIG. 2 is a longitudinal sectional view along II-II; The position of the piston 300 differs between FIGS. 2-4. As shown in FIG. 1, this pump has a roughly columnar shape with an axis extending in the vertical direction (the Z-axis direction in the drawing), and includes, from top to bottom, a top plate 100, a pump head 110, a cylinder 120, and a bottom plate. 130 included. The top plate 100 is a square thin plate made of metal such as stainless steel. As shown in FIGS. 2 to 4, the pump head 110 is a cylinder with a closed upper end, and is a molded product made of fluororesin such as polytetrafluoroethylene (PTFE). The top plate 100 is coaxially overlaid on the pump head 110 . Cylinder 120 is a metal cylinder, for example, aluminum die-cast. Cylinder 120 is coaxially positioned below pump head 110 . The inner and outer diameters of cylinder 120 are smaller than the inner and outer diameters of pump head 110, respectively. A square-shaped flange 121 projects radially from the upper end of the cylinder 120 . The flanges 121 have the same shape and size as the top plate 100, and are arranged in parallel and in the same direction. The top plate 100 and the flange 121 are fastened with bolts 122 at corresponding four corners, and are fixed with the pump head 110 interposed therebetween. The bottom plate 130 is a disk made of metal, such as die-cast aluminum. A bottom plate 130 is coaxially arranged under the cylinder 120 and closes the lower end of the cylinder 120 .
－Pump head－

The upper surface of the pump head 110 is provided with one suction port 111, two discharge ports 112, and one exhaust port 113, all of which communicate with the internal space PMV of the pump head 110. Pipe joints (connectors) 611 , 612 , 613 made of fluororesin such as PTFE are attached to all of the suction port 111 , the discharge port 112 and the vent port 113 . As shown in FIG. 2, in the internal space PMV of the pump head 110, the discharge pipes 115 extend directly downward from each of the discharge ports 112, and their ends are connected to the lower end of the pump head 110 and the flange portion 420 of the rolling diaphragm (see later). ) reaches near the boundary between Although not shown in FIGS. 1 and 2, the suction port 111 is connected to a check valve that allows only a flow from the outside to the inside of the pump head 110, and the discharge port 112 is connected to the flow from inside the pump head 110 to the outside. A check valve is connected that allows only flow.
-Cylinder-

A piston 300 is housed in the internal space RPV, OPV of the cylinder 120 . Piston 300 is a cylinder made of resin such as polypropylene (PP). Since the outer diameter of the piston 300 is slightly smaller than the inner diameter of the cylinder 120, the piston 300 can move in the inner space RPV, OPV of the cylinder 120 in the axial direction (Z-axis direction). The driving method of the piston 300 is, for example, air driving (see below). A lower end portion 310 of the piston 300 has a larger outer diameter than the other portions and includes an annular groove 311 on its outer peripheral surface. An O-ring 312 made of fluororesin such as PTFE is attached to the groove 311, and a slide ring 314 is attached to the outer side in the radial direction thereof. The elastic force of the O-ring 312 seals between the inner peripheral surface of the cylinder 120 and the sliding ring 314 . Since the outer diameter of sliding ring 314 is slightly larger than the inner diameter of cylinder 120, the outer peripheral surface of sliding ring 314 slides along the inner peripheral surface of cylinder 120 while being pressed against the inner peripheral surface. As a result, the region RPV above the lower end portion 310 of the piston 300 in the internal space of the cylinder 120 is hermetically sealed from the region OPV below. On the other hand, an annular protrusion 123 protrudes radially from the inner peripheral surface of the cylinder 120 . Since this protrusion 123 has an inner diameter smaller than the outer diameter of the lower end portion 310 of the piston 300, it prevents the lower end portion 310 from rising. A lateral hole 124 is formed in one of the protrusions 123 of the cylinder 120 in the circumferential direction to allow the region RPV above the lower end portion 310 of the piston 300 to communicate with the outside. This lateral hole 124 is used to lower the air pressure in the upper region RPV (see below). Hereinafter, the upper region RPV will be referred to as the "decompression chamber" and the lower region OPV will be referred to as the "operating chamber."
－Rolling Diaphragm－

A rolling diaphragm 400 is located between the pump head 110 and the cylinder 120 and fluidly separates both internal spaces PMV, RPV. The rolling diaphragm 400 is made of fluororesin such as PTFE. A space PMV surrounded by pump head 110 and rolling diaphragm 400 communicates with suction port 111 and discharge port 112 and is used as a pump chamber.

Rolling diaphragm 400 includes a central disc 410 with an annular collar 420 therearound. The disk portion 410 and the flange portion 420 are connected by an annular thin film portion 430 . The diameter of disk portion 410 is substantially equal to the outer diameter of piston 300 . The disc portion 410 includes a convex portion 411 that bulges downward at the center portion of the bottom surface. This convex portion 411 is fitted into a concave portion 301 included in the central portion of the upper surface of the piston 300 . In this state, a bolt 302 penetrating vertically through the piston 300 is screwed into the convex portion 411 of the disk portion 410 . As a result, the bottom surface of disk portion 410 is brought into close contact with the top surface of piston 300 . The outer diameter of the collar portion 420 is equal to the outer diameter of the pump head 110 . The flange portion 420 is sandwiched and fixed between the pump head 110 and the flange 121 of the cylinder 120 . Collar portion 420 includes an annular groove 421 on its upper surface. An annular protrusion 116 protruding downward from the lower end surface of the pump head 110 is fitted (stabbed) into the groove 421 . As a result, the gap between the upper surface of the flange portion 420 and the lower end surface of the pump head 110 is liquid-tightly sealed. Since the thin film portion 430 is considerably thinner than either the disk portion 410 or the flange portion 420, its elasticity is particularly high. When the air around piston 300 is decompressed through lateral hole 124 of cylinder 120 , thin film portion 430 enters the gap between the inner peripheral surface of cylinder 120 and the outer peripheral surface of piston 300 . In this gap, the thin film portion 430 is folded back as the piston 300 moves. As a result, the disk portion 410 is displaced in the axial direction (Z-axis direction) with respect to the flange portion 420 together with the piston 300 .
－Height sensor－

Three height sensors 501 , 502 and 503 are installed on the outer peripheral surface of the cylinder 120 . These sensors are at the same position in the circumferential direction of the cylinder 120 and at different heights in the axial direction. All of the sensors 501-503 are magnetic sensors, and detect the annular permanent magnet 313 fixed to the upper surface of the lower end portion 310 of the piston 300 from the strength of the magnetic field. The first height sensor 501, which is the lowest among the three height sensors, detects the permanent magnet 313 when the distance from the pump head 110 to the piston 300 is at the allowable upper limit. The next lowest second height sensor 502 detects the permanent magnet 313 when the distance from the pump head 110 to the piston 300 reaches the lower allowable limit. The highest third height sensor 503 detects the permanent magnet 313 when the distance from the pump head 110 to the piston 300 falls below the allowable lower limit and reaches a value larger than the minimum value by a predetermined margin. The piston 300 with the upper acceptable distance from the pump head 110 is shown in FIG. 2, the piston 300 with the lower acceptable distance is shown in FIG. 3, and the piston 300 with the minimum distance is shown in FIG. It is At the position shown in FIG. 4, that is, at the highest point, the permanent magnet 313 of the piston 300 contacts the protrusion 123 on the inner peripheral surface of the cylinder 120, so the piston 300 cannot rise beyond the highest point. Since the discharge pipe 115 extends through the gap between the inner peripheral surface 114 of the pump head 110 and the thin film portion 430 of the rolling diaphragm 400 that occurs when the piston 300 reaches its highest point, the discharge pipe 115 can be , does not contact the rolling diaphragm 400 .
-Bottom plate-

A bottom plate 130 closes the bottom of the working chamber OPV within the cylinder 120 . An annular groove 131 is formed in the upper surface of the bottom plate 130, and an O-ring 132 is installed therein. Since the inner diameter of the groove 131 is larger than the diameter of the operating chamber OPV, the O-ring 132 hermetically seals the bottom of the operating chamber OPV from the outside. Inside the bottom plate 130, a ventilation port 133 penetrates from the outer peripheral surface to the central portion of the upper surface. Air is supplied and exhausted between the outside and the operating chamber OPV through this ventilation port 133 .
[Operation of rolling diaphragm pump]

In the air drive system, the piston 300 moves up and down inside the cylinder 120 by controlling the air pressure inside the working chamber OPV. An external driveline (not shown) monitors the height of piston 300 based on signals from height sensors 501-503, the flow rate of compressed air to be pumped into working chamber OPV through vent 133, Or adjust the flow rate of the air to be sucked out of the working chamber OPV.

When the pump is started, the drive system adjusts the air pressure in the working chamber OPV with the vent 113 open to lower the piston 300 by a predetermined distance. Along with this, a certain amount of nitrogen gas or inert gas is introduced into the pump chamber PMV from the outside through the ventilation port 113 . Since the vent 113 is then closed, gas is maintained in the pump chamber PMV until the pump is stopped.

During the intake process of the pump, air is sucked out of the working chamber OPV and the piston 300 descends until the distance from the pump head 110 reaches the upper allowable limit (see FIG. 2). As a result, the volume of the pump chamber PMV increases, the pressure in the pump chamber PMV decreases, the check valve at the suction port 111 opens, and the check valve at the discharge port 112 closes. Therefore, the fluid FLD flows into the pump chamber from the suction port 111 .

During the discharge process of the pump, compressed air is sent into the working chamber OPV to raise the piston 300, and the distance from the pump head 110 to the piston 300 decreases from the allowable upper limit to the allowable lower limit (see FIG. 3). As a result, the volume of the pump chamber PMV decreases, the pressure in the pump chamber PMV increases, the check valve at the suction port 111 closes, and the check valve at the discharge port 112 opens. Therefore, the chemical liquid flows out from the pump chamber PMV to the discharge port 112 through the discharge pipe 115 (see the arrow shown in FIG. 3).

The vertical movement of the piston 300 by the air drive system is sufficiently gentle, and the discharge pipe 115 is sufficiently long. Therefore, the gas introduced into the pump chamber PMV when the pump is started stays in the pump chamber PMV without being mixed with the liquid chemical FLD or exhausted from the discharge port 112 through the discharge pipe 115 . In particular, the gas maintains the liquid level LLV of the chemical liquid FLD in the pump chamber PMV at a constant height during operation of the pump, and is at a sufficient distance from any of the suction port 111, the discharge port 112, and the vent port 113. keep away from Therefore, the gap between the connector 611 of the suction port 111 and the pump head 110 (not shown), the gap between the connector 612 of the outlet port 112 and the discharge pipe 115, and the connector 613 of the vent port 113 and the pump head 110 None of the gaps between the As a result, there is no risk that the chemical fluid FLD will enter and remain in these gaps. That is, these gaps do not become liquid pools.
[Flushing]

Pumps are periodically flushed. In flushing, first, in a state where the piston 300 is lowered until the distance from the pump head 110 reaches the allowable upper limit (see FIG. 2), cleaning liquid or pure water (hereinafter referred to as "cleaning liquid, etc.") is introduced from the suction port 111 into the pump chamber PMV. ) is sent. As a result, all the chemical liquid FLD remaining in the pump chamber PMV is washed away from the discharge port 112, and the entire pump chamber PMV is washed. The drive train then raises the piston 300 to its highest point (see FIG. 4). As a result, all of the cleaning liquid and the like in the pump chamber PMV is discharged from the discharge port 112 except for the portion remaining in the gap between the inner peripheral surface 114 of the pump head 110 and the thin film portion 430 of the rolling diaphragm 400 . Finally, compressed nitrogen gas or inert gas is sent into the pump chamber PMV through the vent 113 . As a result, all the cleaning liquid remaining in the pump chamber PMV is discharged from the discharge port 112 through the discharge pipe 115 (see the arrow shown in FIG. 4), and the inside of the pump chamber PMV is dried. In particular, since the tip of the discharge pipe 115 is sufficiently separated from both the discharge port 112 and the vent port 113, even if the cleaning liquid or the like is swept away by the gas, the gap between the connector 612 of the discharge port 112 and the discharge pipe 115 is maintained. , and the gap between the connector 613 of the vent 113 and the pump head 110 . That is, the cleaning liquid or the like is reliably removed from the liquid pool including these gaps.
[Advantages of Embodiment]

In the rolling diaphragm pump according to the above embodiment of the present invention, the discharge port 112 is inserted into the gap between the inner peripheral surface 114 of the pump head 110 and the thin film portion 430 of the rolling diaphragm 400 when the piston 300 reaches its highest point. A discharge pipe 115 extends from. During flushing, the cleaning liquid or the like remaining in the liquid pool is discharged through the discharge pipe 115 . The tip of the discharge tube 115 is kept as far away as possible from the reservoir, particularly the suction port 111, the discharge port 112, and the vent port 113 (in FIGS. (near the boundary between Therefore, even if the cleaning liquid or the like is pushed by the gas, there is no danger of it escaping into the gap between the connector 612 of the discharge port 112 and the discharge pipe 115 and the gap between the connector 613 of the vent 113 and the pump head 110 and remaining there. Thus, this rolling diaphragm pump can increase the certainty that residual liquid will be removed from the liquid pool by flushing. As a result, even if the flushing interval is extended, the risk of particles growing in the liquid pool is low. Therefore, this rolling diaphragm pump can reduce the user's burden of maintenance while maintaining high reliability.

Further, since the tip of the discharge pipe 115 is located near the rolling diaphragm 400, this rolling diaphragm pump can repeat normal suction and discharge operations even when a certain amount of gas is retained in the pump chamber PMV. can. During these operations, the gas stays above the pump chamber PMV, keeping the liquid level LLV of the chemical liquid FLD sufficiently away from any of the suction port 111 , the discharge port 112 and the vent port 113 . Therefore, the gap between the connector 611 of the suction port 111 and the pump head 110, the gap between the connector 612 of the discharge port 112 and the discharge pipe 115, and the gap between the connector 613 of the vent port 113 and the pump head 110 do not contact liquid. . Therefore, there is no risk that the chemical fluid FLD will enter and remain in these gaps. That is, these gaps do not become liquid pools. As a result, the number of locations where particles can grow within the pump chamber PMV is reduced, so even if the flushing interval is extended, the risk of particle growth within the pump chamber PMV is further reduced. Therefore, this rolling diaphragm pump can further reduce the user's burden of maintenance while maintaining high reliability.
[Modification]

(1) There is one inlet 111 and two outlets 112 according to the above embodiment of the present invention. However, these numbers are not limited and can be freely changed.

(2) The rolling diaphragm pump according to the above embodiment of the present invention is of a vertical type, in particular, the piston 300 reciprocates vertically. Alternatively, the rolling diaphragm pump may be of the horizontal type and the piston may reciprocate horizontally. In this case, in the pump chamber, the liquid level of the liquid to be transferred should be set above the movement space of the piston, and the suction port and the discharge port should be arranged above the liquid level. Furthermore, the discharge tube may extend through the gap between the inner surface of the side wall of the pump head and the rolling diaphragm that occurs when the piston moves to the lower allowable distance from the pump head to the piston.

(3) The discharge pipe 115 according to the above embodiment of the invention extends from the discharge port 112 into the pump chamber PMV. Alternatively, or in addition to outlet tube 115 , another tube may similarly extend from inlet 111 . If the connector is integral with the pump head 110, the inlet and/or outlet may be located on the side instead of the top of the pump head. In this case, the tube extending from the opening on the side into the pump chamber should be bent and the tip should be extended close to the rolling diaphragm.

(4) The driving method of the piston 300 according to the above embodiment of the present invention is air driving. Alternatively, the piston may be driven by a motor.

(5) In the above embodiment of the present invention, the gap between the inner peripheral surface 114 of the pump head 110 and the thin film portion 430 of the rolling diaphragm 400 when the piston 300 rises to the highest point is the entire circumference of the pump chamber PMV. is expanded by Alternatively, the gap between the inner peripheral surface 114 of the pump head 110 and the thin film portion 430 of the rolling diaphragm 400 may be widened only at the location where the discharge pipe 115 exists in the circumferential direction.

(6) In the above embodiment of the present invention, connectors 611-613 are inserted into pump head 110 at each of inlet 111, outlet 112, and vent 113, and outlet tube 115 is installed at each of outlets 112; It is That is, these connectors 611 - 613 and discharge tube 115 are separate from pump head 110 . Alternatively, these connectors and discharge pipes may be molded integrally with the pump head.

FIG. 5 is a longitudinal section through a pump according to a variant of the above embodiment of the invention. Similar to FIG. 4, piston 300 has risen to its highest point. Four cylindrical protrusions 712 and 713 protrude upward from the upper surface of the pump head 110 . One is located at the inlet 111 , two 712 are located at the outlet 112 and the remaining one 713 is located at the vent 113 . Each projection 712, 713 is used as a pipe joint (connector). In the pump chamber PMV, the upper surface of the pump head 110 protrudes in a tubular shape from each of the discharge ports 112 to form a discharge pipe 715 . The tip of the discharge pipe 715 reaches near the boundary between the pump head 110 and the cylinder 120 . During the pump discharge operation and flushing, the liquid FLD in the pump chamber PMV is sucked from the tip of the discharge pipe 715 and led to the discharge port 112 .

The tip of the discharge tube 715 is kept as far away as possible from the reservoir, in particular the inlet 111, the outlet 112 and the vent 113 (in FIG. near) is installed. Therefore, in flushing, even if the cleaning liquid or the like is pushed by the gas, there is no danger of it escaping into the liquid pool and remaining there. Thus, this rolling diaphragm pump can increase the certainty that residual liquid will be removed from the liquid pool by flushing. As a result, even if the flushing interval is extended, the risk of particles growing in the liquid pool is low. Therefore, this rolling diaphragm pump can reduce the user's burden of maintenance while maintaining high reliability.

Connectors 712, 713 and discharge tube 715 are integral with pump head 110 as described above. In this case, none of the suction port 111, the discharge port 112, and the ventilation port 113 has a gap into which the liquid can enter, that is, a liquid pool. Therefore, unlike the above embodiment, it is not necessary to introduce gas into the pump chamber PMV to keep the liquid surface of the chemical liquid FLD away from the suction port 111 , the discharge port 112 and the vent port 113 .

100 top plate
110 pump head
111 suction port
112 outlet
113 Vent
115 discharge pipe
120 cylinder
121 flange
122 volts
123 Cylinder Protrusion
124 Side hole of cylinder
130 bottom plate
131 bottom plate groove
132 O-ring
133 ventilation openings
300 piston
301 piston recess
302 piston bolt
310 lower end of piston
311 Piston groove
312 O-ring
313 permanent magnet
400 rolling diaphragm
410 Rolling Diaphragm Disc
411 Rolling Diaphragm Convex
420 Rolling Diaphragm Collar
430 Rolling Diaphragm Thin Film
501-503 Height sensor
611-613 connector

Claims (4)

a head, which is a cylindrical member closed at one end and open at the other end, and includes a suction port and a discharge port communicating with an internal space at the one end or a side close to the one end in the axial direction ;
a cylinder positioned below or to the side of said head and closed at one end by said head;
A displaceable member that partitions the head and the cylinder to form a pump chamber in the internal space of the head, and that displaces fluid from the suction port to the pump chamber or from the pump chamber to the pump chamber. a rolling diaphragm that moves to the outlet;
a piston, which is a cylindrical member capable of reciprocating between the inner space of the head and the inner space of the cylinder , connected to the rolling diaphragm at an end closer to the head, and displacing the rolling diaphragm by reciprocating motion; ,
a tube extending into the pump chamber from at least one of the inlet and the outlet, said rolling diaphragm pump comprising :
When the piston moves until the distance from one end of the head to the end of the piston closer to the head reaches an allowable lower limit, a gap is formed between the inner peripheral surface of the head and the rolling diaphragm,
the tube is positioned in the gap and the tip of the tube reaches near the boundary between the head and the cylinder;
In flushing, the fluid pumped into the pump chamber is expelled through the tube from the tip of the tube.
A rolling diaphragm pump characterized by: 2. A rolling diaphragm pump according to claim 1, wherein said tube is integrally molded with said head. The head is
3. A rolling diaphragm pump according to claim 1, comprising pipe joints provided at said suction port and said discharge port. 4. A rolling diaphragm pump according to claim 3, wherein said pipe joint is molded integrally with said head.

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