JP4923002B2 - Liquid pump system, pump device, and control method of rolling diaphragm pump - Google Patents

Description

The present invention relates to a control method for a liquid pump system, a pump device , and a rolling diaphragm pump, and more particularly to a liquid pump system, a pump device , and a control method for a rolling diaphragm pump that can be suitably used for semiconductor and liquid crystal processes.

  In a rolling diaphragm pump, the inner periphery of a rolling diaphragm is attached to a piston that is housed in a cylinder and driven to reciprocate. The outer periphery of the rolling diaphragm pump is attached to the cylinder, and the piston is sealed by a rolling diaphragm in the cylinder. The fluid suction port and the discharge port are respectively opened in a pump chamber (pressure chamber) whose volume is changed by the movement of. Therefore, if the fluid suction port and the discharge port are connected to the fluid tank and the discharge fluid supply unit via check valves, respectively, the volume of the pump chamber changes with the reciprocating drive of the piston. In the process of expanding, fluid is sucked from the suction port, and in the process of contracting, fluid is discharged from the discharge port.

  For example, as disclosed in Patent Document 1, in a rolling diaphragm pump, a thin film-shaped rolling diaphragm stably maintains a predetermined posture (folded reverse posture) so as to contribute to high discharge accuracy by good pumping. Ingenuity that can be maintained has been made. That is, a decompression chamber surrounded by the back surface of the rolling diaphragm, the cylinder and the piston is provided on the back side (the anti-pump chamber side) of the rolling diaphragm, and the decompression chamber is decompressed by decompression generating means communicating through the cylinder. The rolling diaphragm is always sucked to the inner wall surface of the cylinder, so that the above inverted posture is always and clearly maintained.

  The decompression chamber is a place where the rolling diaphragm is decompressed so as to be always at a lower pressure than the pump chamber in order to maintain the posture in which the rolling diaphragm follows the cylinder inner peripheral wall and the piston outer peripheral wall without any gap. The pressure-reducing means such as a vacuum generator is always driven so that the pressure can be maintained. Therefore, there is an advantage that the posture of the rolling diaphragm can be maintained, but on the other hand, there is a new disadvantage that the decompression means must always be driven. In addition, in a structure with a piston that reciprocates in a cylinder, it is difficult to eliminate the leakage in the decompression chamber because a sliding seal is generally used. A configuration is employed in which air is constantly sucked from the decompression chamber using the means.

Therefore, in conventional rolling diaphragm pumps such as a pump device and a liquid pump system and devices using the same, a device for decompressing the decompression chamber, that is, a decompression means as an auxiliary device for the pump, is large for its function. Thus, there are disadvantages such as an increase in the size of the apparatus and a decrease in efficiency of the pump and the apparatus as a whole due to the constant drive of the decompression means, leaving room for improvement.
JP 2007-023935 A

The purpose of the present invention is to reduce the size and simplify the decompression device for maintaining the posture of the rolling diaphragm by devising the pump structure, and to reduce or suppress the increase in size and efficiency of the device , the pump device , In addition, a control method for the rolling diaphragm pump is developed and provided.

The invention according to claim 1, shea cylinder 1, a piston 2 which is driven back and forth movement is housed in the cylinder 1, the cylinder 1 through the turned-back portion 3d of the inner peripheral portion 3c and the piston outer periphery, which is supported by the piston 2 A rolling diaphragm 3 having an outer peripheral portion 3e supported by the pump, a pump chamber 4 partitioned by the rolling diaphragm 3 in the cylinder 1 and changing in volume by the movement of the piston 2, and a back side of the rolling diaphragm 3 A rolling diaphragm pump 70 having a decompression chamber 26 formed by being surrounded by the cylinder 1, the piston 2 and the rolling diaphragm 3, and a discharge for opening and closing a discharge side flow path 30 with respect to the rolling diaphragm pump 70. For the side valve 28 and the rolling diaphragm pump 70 A suction side valve 27 that opens and closes the suction side flow path 29, closes the discharge side valve 28, and opens the suction side valve 27 to cause the rolling diaphragm pump 70 to perform a suction operation. A liquid configured to be switchable between a suction drive state and a discharge drive state in which the discharge side valve 28 is opened and the suction side valve 27 is closed and the rolling diaphragm pump 70 is discharged. In the pump system,
When switching from the discharge drive state to the suction drive state, the discharge side valve 28 is opened and the suction side valve 27 is closed and the rolling diaphragm is closed as the discharge drive state ends. The pump 70 is switched to the suction drive state through a reverse drive state in which the suction operation is performed, and
When switching from the discharge drive state to the reverse drive state, the rolling diaphragm pump 70 is in a state where the open state of the discharge side valve 28 and the closed state of the suction side valve 27 are maintained. It is configured to be immediately switched from the discharge operation to the suction operation,
The discharge-side valve 28 and the suction-side valve 27 move the valve body 61 by using air so that the valve body 61 is in contact with the valve seat 62 and the valve body 61 is in the valve seat 62. It is configured as an air operated valve that can be switched to a valve open state that is away from
A control valve 39 for controlling air supply / discharge to the discharge side valve 28 and the suction side valve 27 and a discharge side and suction side air supply / discharge passage 41 connecting the discharge side valve 28 and the suction side valve 27; 40, and a throttle means 43 that throttles the air passing through the discharge-side air supply / exhaust passage 41 is provided,
A pressure reducing means 35 for reducing the pressure of the said decompression chamber 26, with each comprising a suction portion 6 and the discharge section 7 of the fluid communicating with the pump chamber 4, is a pre-Symbol decompression means 35 and the vacuum chamber 26, The decompression chamber 26 communicates via a check valve V that allows the decompression operation of the decompression chamber 26 and blocks the pressure increase operation of the decompression chamber 26 ,
The suction operation of the rolling diaphragm pump 70 in the reverse drive state follows the high-speed suction operation immediately after switching from the discharge operation, the medium-speed suction operation following the high-speed suction operation, and the medium-speed suction operation. It is characterized by being set to a three-stage switching drive state by a low-speed suction operation .

The invention according to claim 2 is characterized in that the pump device includes the liquid pump system according to claim 1 .

The invention according to claim 3 is the liquid pump system according to claim 1 or the pump device according to claim 2, wherein the top dead center at which the pump chamber volume is minimized from the bottom dead center position at which the pump chamber volume is maximized. Control means 77 for ending the decompression operation of the decompression means 35 is provided before the start of the discharge operation in which the piston 2 moves toward the position.

According to a fourth aspect of the present invention, there is provided a method for controlling a rolling diaphragm pump, wherein the pressure reducing means 35 of the liquid pump system according to the first aspect or the pump device according to the second aspect has a maximum pump chamber volume. The piston 2 is driven so as to be terminated before the start of the discharge operation in which the piston 2 moves from the bottom dead center position toward the top dead center position where the pump chamber volume is minimized.

According to the invention of claim 1, although described in detail in the section of the embodiment, by providing the check valve, the decompression chamber can be maintained at a predetermined low pressure state without always driving the decompression means. As a result, it has been found that the driving time of decompression means such as a vacuum generator and an air suction device can be greatly reduced as compared with the conventional one. As a result, by devising the pump structure, it is possible to reduce or simplify the decompression device for maintaining the posture of the rolling diaphragm, and to provide a liquid pump system capable of eliminating or suppressing the increase in size and the decrease in efficiency of the device. it can.

Further, when switching from the discharge drive state to the reverse drive state, the pump is immediately switched from the discharge operation to the suction operation while the open state of the discharge side valve and the closed state of the intake side valve are maintained. Therefore, the liquid in the liquid discharge section such as the nozzle does not cause unstable pressure behavior such as temporary discharge pressure acting or pressure fluctuation when switching from the discharge state to the suction state. The dripping prevention function by reverse driving functions. As a result, the residual pressure of the pump acts on the discharge side flow path, or the pressure fluctuates when switching to the suck-back operation. Become so. Therefore, further devise a configuration that prevents liquid dripping from occurring in the suck back operation of the pump , that is, the high speed suction operation immediately after the suction operation of the rolling diaphragm pump in the reverse drive state is switched from the discharge operation. Desirably improved to eliminate any unexpected dripping by setting the three-stage switching drive state by the medium-speed suction operation following the high-speed suction operation and the low-speed suction operation following the medium-speed suction operation A liquid pump system can be provided.

  In addition, there is an advantage that a problem newly generated can be solved by configuring the discharge side valve with an air operated valve having excellent responsiveness. In other words, the closing operation of the air operated valve causes a pumping action in the flow path to the liquid discharge section, and there is a possibility that the liquid may leak despite the suck back operation, which is a new problem. However, by providing a throttle means that throttles the air passing through the discharge-side air supply / discharge path, the adverse effect of the pumping action of the discharge-side air operated valve is substantially eliminated, and the air-operated valve has excellent response without fear of dripping. The liquid pump system can be improved and the liquid pump system can be improved.

According to the invention of claim 2, although described in detail in the section of the embodiment, by providing a check valve, the decompression chamber can be maintained at a predetermined low pressure state without always driving the decompression means. As a result, it has been found that the driving time of decompression means such as a vacuum generator and an air suction device can be greatly reduced as compared with the conventional one. As a result, by devising the pump structure, the pressure reducing device for maintaining the posture of the rolling diaphragm can be reduced in size and simplified, and the pump device capable of eliminating or suppressing the increase in size and efficiency reduction of the device can be provided. .

  Further, as in claim 3, there is provided a control means for ending the decompression operation of the decompression means before the start of the ejection operation, for example, driving the decompression means for a short time immediately before the discharge process of the pump. There is an advantage that the effect by the inventions of claim 1 and claim 2 due to the provision of the stop valve can be further enhanced. This advantage can be similarly obtained in the method of controlling the rolling diaphragm pump according to claim 4.

Hereinafter, an embodiment of a rolling diaphragm pump according to the present invention will be described with reference to the drawings when used in a liquid pump system. 1 is a block diagram showing a liquid pump system, FIG. 2 is a partially cutaway side view of a pump device, FIGS. 3 and 4 are sectional views of a rolling diaphragm pump, a sectional view when a piston is extended, and FIG. 5 is a drawing of a rolling diaphragm pump. FIG. 6 is a time chart showing the operation state with each valve, FIG. 6A is an operation diagram showing a reverse drive state by one stage, FIG. 7B is a main part diagram of the time chart, and FIG. FIG. 8 shows the main part of the time chart in the reverse drive state, where (a) is a two-stage switching type and (b) is a three-stage switching type main part diagram. Further, FIG. 9 is embodied block diagram suction side valve and the discharge side valve of the liquids pump system and its operation system, Figure 10 is a sectional view showing the structure of the air-operated valve, the structure of FIG. 11 is a needle valve FIG. 12 is an action diagram showing the inconvenient behavior of the nozzle liquid level accompanying the closing operation of the discharge side valve, FIG. 13 is an action diagram of the main part showing the improvement status of the nozzle liquid level, and FIG. FIG. 15 is a sectional view of a double rolling diaphragm pump.

[Example 1]
A liquid pump system A having a rolling diaphragm pump 70 is shown in FIG. This system A has a chemical tank 31, a pump device P, a filter 32, a nozzle 33, a suction side valve 27, a discharge side valve 28, a suction side flow path 29, and a discharge side flow path 30. Configured. A suction side valve 27 is provided in the middle of the suction side flow passage 29 extending between the suction portion 6 of the pump device P and the chemical liquid tank 31, and the discharge side flow passage 30 extending between the discharge portion 7 of the pump device P and the nozzle 33 is provided in the discharge side flow passage 30. The discharge side valve 28 and the filter 32 are provided.

  Each of the suction side and discharge side valves 27 and 28 is configured as a two-position switching type air operated valve that operates so as to be switched between an open state and a closed state by air pressure. Among a plurality of fluid devices provided in the discharge side flow path 30, that is, the discharge side valve 28, the filter 32, and the nozzle 33, a nozzle (an example of a liquid discharge unit) 33 provided at the end of the discharge side flow path 30. Except for the filter 32, the fluid device disposed most downstream in the liquid flow direction is set in the filter 32. Reference numeral 34 denotes a wafer as an application target (liquid supply target) of the chemical liquid e.

  The pump device P will be described. 2 to 4 and 14, the pump device P includes a cylinder 1, a piston 2 accommodated in the cylinder 1 and driven to reciprocate, an inner peripheral portion 3 c attached to the piston 2, and a piston Surrounded by a rolling diaphragm 3 made of fluororesin such as PTFE having an outer peripheral portion 3e attached to the cylinder 1 via an outer peripheral folded portion 3d, and the cylinder 1 and the rolling diaphragm 3, and is partitioned by the rolling diaphragm 3 in the cylinder 1 And a pump chamber (pressure chamber) 4 whose volume is changed by the movement of the piston 2, a liquid suction portion (also referred to as a suction port) 6 and a discharge portion (also referred to as a discharge port) 7 each communicating with the pump chamber 4. It has the rolling diaphragm pump 70 provided with.

  In the rolling diaphragm pump 70, a piston 2 is accommodated in the cylinder 1 so as to be movable in the axial direction, and a reciprocating motion is given to the piston 2 by a pump drive source and a rotation preventing means described later. The piston 2 has an annular packing groove 2e formed at an intermediate portion in the moving direction, a tip portion 2b on the cylinder head side from the annular packing groove 2e, and a base end portion 2a on the piston base side on the opposite side, a screw hole 2d, and the like. It is configured in a straight barrel shape. Although the position of the rolling diaphragm 3 relative to the piston 2 is depicted slightly different between that shown in FIG. 2 and that shown in FIGS. 3 and 4, any type of structure may be adopted.

  The rolling diaphragm 3 that defines the pump chamber 4 with the cylinder head 1a includes a screw shaft portion 3a, a flange portion 3b, a diaphragm inner peripheral portion 3c, a diaphragm outer peripheral portion 3e, a ring portion 3f, and a head 3g. It is formed. The screw shaft portion 3 a is screwed into a bottomed screw hole 2 d provided coaxially on the tip surface of the tip portion 2 b of the piston 2. The flange portion 3 b is formed so as to protrude in the radial direction from the outer peripheral surface at one end on the head side of the screw shaft portion 3 a, and is closely bonded to the outer edge portion of the tip end surface 2 b of the piston 2. The diaphragm inner peripheral portion 3c extends in the axial direction from the end portion of the flange portion 3b along the outer peripheral surface of the front end portion 2b of the piston 2 and is in close contact with the outer peripheral surface of the front end portion of the front end portion 2b of the piston 2. It is a shape.

  The diaphragm outer peripheral part 3e extends from the end of the diaphragm inner peripheral part 3c through the U-shaped folded part 3d along the inner peripheral surface on the cylinder head side of the cylinder 1 in the axial center C direction. It is a thin film that is in close contact with the inner peripheral surface on the head side. The folded portion 3d is folded back so as to protrude toward the decompression chamber 26 (on the side opposite to the cylinder head 1a) in the direction along the axis (pump axis) C in the reciprocating direction of the piston 2. The ring portion 3f extends in a radial direction from the end of the rolling diaphragm outer peripheral portion 3e, and is sandwiched between the cylinder 1 and a cylinder head (pump head) 1a at one end thereof. The head 3g protrudes from one end surface on the head side of the screw shaft portion 3a and has a two-face notch structure for fitting a tool such as a wrench when the screw shaft 3a is screwed into the screw hole 2d. Is formed of things.

  An O-ring 5 made of fluoro rubber as a seal member is provided between the joint surfaces of the cylinder 1 and the ring portion 3f, and a lip seal portion (illustrated) formed on the cylinder head 1a is provided between the joint surfaces. (Not shown) is sealed against the surface of the ring portion 3f. FIG. 3 shows the rolling diaphragm 3 when the piston 2 moves to the stroke end position in the suction process, and the rolling diaphragm outer peripheral portion 3e is greatly swollen with respect to the rolling diaphragm inner peripheral portion 3c. Yes. The rolling diaphragm pump 70 may be equipped with the rolling diaphragm 3 in which the state shown in FIG.

  The cylinder head 1 a has a fluid suction portion 6 and a discharge portion 7 communicating with the pump 4. The suction part 6 is connected in communication with the chemical liquid tank 31 via a suction side flow path 29 provided with a suction side valve 27, and the discharge part 7 is connected via a discharge side flow path 30 provided with a discharge side valve 28 and a filter 32. The nozzle 33 is connected in communication. As described above, at the time of discharge, only the discharge side valve 28 is opened and the suction side valve 27 is closed, and at the time of suction, the discharge side valve 28 is closed and only the suction side valve 27 is opened.

  In the above configuration, when the piston 2 is reciprocated by the pump driving source and the rotation preventing means, which will be described later, and the piston 2 is reciprocated in the cylinder 1, the volume of the pump chamber 4 increases. (Right line process in FIGS. 3 and 4) The chemical liquid e in the chemical liquid tank 31 is sucked into the pump chamber 4 in the pump chamber 4 and the volume of the pump 4 is reduced (the left line process in FIGS. 3 and 4). ), The chemical solution e in the pump 4 is supplied to the nozzle 33. Therefore, the chemical solution e in the chemical solution tank 31 can be supplied to the nozzle 33 by the reciprocating drive of the piston 1.

  The pump device P is provided with a linear actuator 8 as a pump drive source so that the pump discharge amount and the discharge speed can be changed and adjusted by stroke control of the piston 2. The linear actuator 8 includes a multi-phase (for example, five-phase) stepping motor unit 9 and a linear motion mechanism unit 10 that converts the rotational motion of the motor unit 9 into a linear motion and outputs the linear motion. The motor unit 9 includes a hollow rotating shaft 11, a rotor 12 attached to the outer peripheral surface of the rotating shaft 11, and a stator 13 provided around the rotor 12. The rotating shaft 11 has a stepped structure including a small-diameter portion 11a supported by a bearing 14 and a large-diameter portion 11b supported by a bearing 15 that receives both thrust load and radial load, and rotates to the small-diameter portion 11a. A screw nut 16 (to be described later) is disposed in the large-diameter portion 11b while the child 12 is attached. Note that the inner of the bearing 15 is fixed to the large-diameter portion 11b by a lock nut 17 that is screwed onto the outer peripheral surface of the end portion of the large-diameter portion 11b. In this configuration, in the motor unit 9, the rotating shaft 11 rotates together with the rotor 12 with energization of a stator winding (not shown).

  An output screw shaft (ball screw shaft) 18 is coaxially penetrated through the hollow portion of the rotating shaft 11, and a screw nut (ball screw nut) 16 screwed into the output screw shaft 18 is inserted into the large diameter portion 11b. Has been inserted. The screw nut 16 has a flange portion 16 a that protrudes in the radial direction from the open end of the rotary shaft 11 on the large diameter portion 11 b side, and the flange portion 16 a is fixed to the lock nut 17 via a bolt 74. In this configuration, the screw nut 16 can rotate together with the rotating shaft 11.

  The output screw shaft 18 is linearly moved in the axial direction along with the rotation of the screw nut 16 by restricting the rotation about the axis thereof by a rotation preventing means described later. Therefore, in this linear actuator 8, the rotational motion of the rotary shaft 11 is converted into the linear motion of the output screw shaft 18. The linear actuator 8 is coaxially attached to the end of the cylinder 1 opposite to the cylinder head, and one end of the output screw shaft 18 is coaxially connected to the base end 2a of the piston portion 2 by a screw connection. ing. Thus, the output screw shaft 18 of the linear actuator 8 is configured to function as a piston rod.

  By the way, since the piston 2 is connected to the cylinder 1 via the rolling diaphragm 3, it is not possible to restrict the rotation of the piston 2 and the output screw shaft 18 around the same axis line by the presence of the rolling diaphragm 3. is there. However, in that case, a rotational moment (twisting force) acts on the rolling diaphragm 3, and there is a possibility that a crack or a hole or the like may occur in the rolling diaphragm 3 made of fluororesin or the like.

  Therefore, in the present embodiment, a detent means is provided between the piston 2 and the cylinder 1 in the rolling diaphragm pump 70 to allow the piston 2 to reciprocate and restrict rotation. Specifically, the anti-rotation means includes a long hole 19 formed in the side wall of the cylinder 1 along the axis, and one end screwed into the outer peripheral surface of the distal end side of the base end portion 2a of the piston 2 to fix the piston 2 The engaging pin 20 is mounted in a protruding shape in the radial direction from the outer peripheral surface of the distal end side of the base end portion 2 a, and the other end protrudes out of the cylinder 1 through the long hole 19 of the cylinder 1. In this configuration, the engagement pin 20 reciprocates integrally with the piston 2.

  In the above configuration, the piston 2 is restricted from rotating around the axis C, and can reciprocate in the axial direction within the range of the long hole 19, and the output screw shaft 18 and the rolling unit integrally coupled to the piston 2 are provided. The rotation about the axis C of the diaphragm 3 is also restricted at the same time, and the linear actuator 8 reciprocates the piston 2 while preventing the rolling diaphragm 3 from giving a rotational moment and thereby preventing cracks and holes. can do. Therefore, the piston stroke can be controlled, and the discharge amount and discharge speed of the pump can be changed and adjusted.

  Further, the pump device P includes a sensor (an example of a position detection unit) 21 for detecting a reference position of the piston 2 when performing stroke control (pump discharge amount and discharge speed control) of the piston 2. It has been. The sensor 21 includes, for example, a light emitting element (not shown) attached to one end of the tip of the sensor base 22 whose tip is branched in a U-shape, and a light emitting element attached to the other end of the tip of the sensor base 22 to emit light. An element (not shown) and a light receiving element (not shown) arranged to face each other with a predetermined interval are configured in a photoelectric manner.

  Further, between the sliding surface of the cylinder 1 and the piston 2, that is, between the inner peripheral surface of the cylinder 1 and the outer peripheral surface of the base end portion 2a of the piston 2, an outer peripheral surface of the base end portion 2a of the piston 2 is annular. An O-ring 23 made of fluoro rubber as a seal member through a packing groove 2e, and a slipper ring 24 made of fluoro-resin such as polytetrafluoroethylene (PTFE) disposed on the outer periphery of the O-ring 23 Is provided. In addition, an air suction port 25 is provided on the side wall of the cylinder 1 in the vicinity of the back portion 3d (right side in FIGS. 3 and 4) at the stroke end position in the piston 2 suction step. Thus, in the cylinder 1, the rolling diaphragm 3, the O-ring 23, the inner peripheral surface of the cylinder 1, and the piston 2 are arranged on the side opposite to the side where the pump chamber 4 is present with respect to the rolling diaphragm 3. A decompression chamber 26 defined by the tip 2b, the slipper ring 24 and the O-ring 5 and communicating with the air suction port 25 is provided.

  As shown in FIGS. 2 to 4, the aspirator (an example of a vacuum generator and a decompression unit) 35 and the decompression chamber 26 allow the decompression operation of the decompression chamber 26 and increase the pressure of the decompression chamber 26. Is communicated via a check valve V for blocking. Specifically, a check valve V is interposed in a state where the pressure reducing channel 76 that connects the aspirator 35 and the air suction port 25 is connected directly to the air suction port 25. The pressure of the decompression chamber 26 is sufficiently lower than the pressure of the pump chamber 4 by the intake action of the aspirator 35, and the decompressed state can be maintained.

  Before the start of the discharge operation in which the piston 2 moves from the bottom dead center position K where the pump chamber volume is maximum to the top dead center position J where the pump chamber volume is minimum, Intermittent control means 77 for ending the decompression operation (evacuation) is provided. Specifically, as shown in FIG. 1, a pressure reduction control device formed by connecting (electrically) the sensor 21 and the aspirator 35 via an intermittent control means 77 and a storage unit 78 included in the control device 38. 79 is configured. Note that the control device 38 may be provided in a casing constituting the pump device P.

  That is, the rolling diaphragm pump 70 is basically stopped (standby) with the piston 2 being at the bottom dead center position K. For example, the storage unit 78 determines the drive and stop times of the rolling diaphragm pump 70. Equipped with a timer function. Accordingly, as shown in FIG. 5 as an example, slightly before the time for the next piston 2 to perform the discharging operation (when the discharging step starts in FIG. 5), the driving of the aspirator 35 is started at t8 + t7 seconds before, and t7 seconds. The intermittent control means 77 functions so as to be stopped later. However, the intermittent control is performed on the assumption that the detection information of the sensor 21 that the piston 2 is at the bottom dead center position K is maintained. For example, the aspirator 35 is driven 1 second (t8) +2 seconds (T7) = 3 seconds before the start of pumping, and is stopped before 1 second (t8), or a short time immediately before the pump 70 is driven (1- The aspirator 35 is driven only for 3 seconds). The predetermined low pressure state of the decompression chamber 26 is effectively maintained until the next time the aspirator 35 is driven by the check function of the check valve V.

  The check valve V interposed in the decompression flow path 76 can significantly reduce the air consumption as compared with a specification not equipped with the check valve V. That is, even after the evacuation of the aspirator 35 is stopped, the effective decompression state of the decompression chamber 26 can be maintained for a certain time. The time during which the decompression chamber 26 can be maintained in the decompressed state after the evacuation is stopped is about several tens of seconds to 1 minute, and the pump driving time for one shot is about 10 seconds. Therefore, in the system in which the check valve V is added to the decompression flow path 76, the aspirator 35 is driven only when the pump drive is started (exactly, just before the pump drive is started), and the decompression state of the decompression chamber 26 (example: If a low pressure state close to vacuum is created, the decompression chamber 26 can always be maintained in a predetermined decompression state while the pump is driven even if the evacuation is stopped thereafter (see FIG. 5).

  The aspirator driving time (evacuation time) t7 when the rolling diaphragm pump 70 is driven is about 1 to 3 seconds (see FIG. 5). For example, in a system that discharges at intervals of 30 seconds, vacuuming is performed only immediately before the start of pump driving. By adopting the configuration, it is possible to reduce the amount of air consumed for the pump to 1/10 or less of the conventional one. Needless to say, even when intermittent operation is performed in this way, it is possible to maintain the same pump discharge accuracy as that of the conventional means for constantly evacuating. Accordingly, the pressure reducing operation time is greatly shortened (about 1/10) as compared with the conventional case, and the driving cost is greatly reduced. A predetermined posture of the rolling diaphragm 3 is maintained, and the pump function can be satisfactorily performed.

  In FIG. 5, t <b> 7 is a drive time of the aspirator 35, and t <b> 8 is a delay time of the decompression start of the decompression chamber 26 by the aspirator 35. It can be seen that the decompression chamber 26 is depressurized from the atmospheric pressure to a predetermined low pressure state by driving the aspirator 35 at time t7, and thereafter, the decompression state of the decompression chamber 26 is maintained as it is even if the aspirator 35 is stopped.

  By the way, the decompression operation time for maintaining the rolling diaphragm 3 in a predetermined convex posture, that is, the time during which the aspirator 35 is driven, is during the operation of the rolling diaphragm 3, that is, from the start of the discharge process of the pump 70 to the suction process. Only the time until the process is completed may be used, and even in this case, the driving time can be reduced to about 1/3 as compared with the conventional case of constant driving. As a result of further earnest research, an innovative pump device and liquid pump that can reduce the driving time to about 1/10 of the conventional time by adopting the means for adding the check valve V as described above. A system and a method for controlling a rolling diaphragm pump can be provided.

  Next, an operation method of the liquid pump system A will be described. In the liquid pump system A, the discharge side valve 28 is closed, the suction side valve 27 is opened, and the pump device P is inhaled (inhalation drive state), and the discharge side valve 28 is opened. And a discharge step (discharge drive state) in which the suction side valve 27 is closed and the pump A is discharged to be switched. That is, the chemical liquid e discharged by one discharge operation (pumping) due to the piston 2 projecting and moving in the pump device P is discharged from the nozzle 33 and supplied dropwise to the wafer 34. Then, during the next inhalation process, the wafer 34 to which the chemical solution e is supplied is sent out, and if the wafer replacement process for positioning the untreated wafer 34 directly under the nozzle 33 is performed, the pump device P is continuously connected. The chemical solution e can be continuously supplied to the wafer 34 by being driven.

  That is, the suction drive state in which the discharge side valve 28 is closed and the suction side valve 27 is opened to cause the pump device P to perform the suction operation, the discharge side valve 28 is opened, and the suction side valve 27 is turned on. The liquid pump system is configured to be able to alternately switch between a discharge driving state in which the valve is closed and the pump device P is discharged. When switching from the discharge drive state to the suction drive state, the reverse side drive opens the discharge side valve 28 and closes the suction side valve 27 to perform the suction operation of the pump device P as the discharge drive state ends. The state is switched to the suction drive state through the state. When switching from the discharge drive state to the reverse drive state, the pump device P immediately performs the suction operation from the discharge operation while the open state of the discharge side valve 28 and the closed state of the suction side valve 27 are maintained. It is comprised so that it can be switched to.

  And the device for preventing the unexpected liquid dripping from the nozzle 33 after completion | finish of a discharge process is made | formed. That is, when switching from the discharge process to the suction process, the reverse drive process of opening the discharge side valve 5 and closing the suction side valve 27 to perform the suction operation of the pump device P with the end of the discharge process. When switching to the suction process through (reverse drive state) and when switching from the discharge process to the reverse drive process, the open state of the discharge side valve 28 and the closed state of the suction side valve 27 are maintained. Thus, the pump device P is configured to be immediately switched from the discharge operation to the suction operation. In addition, the suction operation of the pump device P in the reverse drive process is based on a high-speed suction operation immediately after switching from the discharge operation, a medium-speed suction operation following the high-speed suction operation, and a low-speed suction operation following the medium-speed suction operation. The three-stage switching drive state is set.

  That is, as shown in FIG. 1, a suction side drive mechanism 36 that drives and opens the suction side valve 27, a discharge side drive mechanism 37 that drives and opens the discharge side valve 28, and the suction side and discharge side drive mechanisms 36. 37 and a control device 38 that controls the driving state of the pump device P are provided to constitute a dripping prevention device B. As shown in FIG. 5, the function (action) of the liquid dripping prevention device B is accompanied by the end of the discharge process in which the pump device P is driven positively (+) over time t1 so as to move the piston 2 in the pushing direction. Immediately, the pump device P is driven at a high speed (minus) for a time t2 so as to move the piston 2 in the retracting direction, and the pump device P is continuously driven at a medium speed for a time t3 (minus (−)). Subsequently, a reverse driving process (suck back process) is performed in which the pump device P is driven at a low speed (−) at a low speed for a time t4. After the reverse driving process, the suction process is performed over time t6.

  When the discharge side valve 28 of the pump device P is closed after completion of the suck back process, if there is a slight flow of chemical liquid in the discharge direction (rebound phenomenon), the amount of outflow is added from the desired amount of chemical liquid suction. By sucking the amount in advance, the chemical solution e can be retained at a desired position when the discharge side valve 28 is closed. In addition, when the internal pressure of the pump device P is high at the start of the discharge process, if the chemical liquid e may move in the discharge direction at the moment when the discharge side valve 28 is opened, this should be prevented. After the suction process is completed, the pressure of the pump chamber 4 is adjusted by moving the rolling diaphragm 3 to an arbitrary position in a state where both the suction side valve 27 and the discharge side valve 28 are closed. It is possible to prevent inadvertent movement.

[Consideration of reverse drive operation (suckback operation)]
During the suck back operation, the liquid extrusion of the discharge side valve must be sucked in advance, but in one suck back operation, it is necessary to increase the suction speed in order to improve the liquid drainage. That is, by maintaining the open state of the discharge side valve 28 and the closed state of the suction side valve 27, the pump device P is switched from the discharge operation to the high speed suction operation at once without stopping temporarily. As shown in FIG. 5, it is considered that the chemical liquid e at the tip of the nozzle 33 can be sucked in at a stroke to prevent dripping until the next chemical liquid is discharged.

  However, if the suction speed is set at a considerably high speed (see FIG. 6B) to prevent dripping, bubbles are generated in the tip of the nozzle 33 when the chemical liquid e is sucked as shown in FIG. Inconveniences that occur or that a thin film is formed may occur in rare cases. Therefore, as shown in FIG. 7, in order to avoid the inconvenience, the suction operation of the pump device P in the reverse drive state is a high-speed suction operation immediately after switching from the discharge operation, and a low-speed suction operation following the high-speed suction operation. I tried to set the two-stage switching drive state. As a result, the generation of bubbles and the formation of a thin film did not occur as expected, but when switching from the high-speed suction operation in the reverse drive state to the low-speed suction operation, as depicted in the left and right central portions in FIG. A new problem has arisen that the liquid dripping rarely from the tip of the nozzle 33.

  In other words, in the initial prediction, as shown by the arrow a shown by the broken line in FIG. 7, the generation of bubbles is caused by the quick suction by the first high-speed suction operation in the reverse drive process and the subsequent second low-speed suction operation. We thought that dripping could be prevented without forming a thin film. However, when switching from the high-speed suction operation to the low-speed suction operation, the instantaneous suction speed becomes zero in the control (high speed → zero → low speed), and it is found that liquid dripping may occur due to the instantaneous speed zero. It was done. That is, as shown by arrows B and C in FIG. 7, the chemical solution e may dripping when switching from suction by high-speed suction to low-speed suction.

The countermeasure is to shift from the high-speed suction operation directly to the low-speed suction operation without once reducing the speed to zero. 1. means for switching from high speed to low speed without setting the suction speed to zero once (in the two-stage switching drive state, see the phantom line graph in FIG. 8A); Means for switching the suction speed from the high speed to the medium speed without once becoming zero, and switching from the medium speed to the low speed without once making it zero (in the three-stage switching drive state, FIG. 5 and FIG. See]. The liquid pump system A according to the first embodiment performs 2. a more precise liquid dripping prevention control. The three-stage switching drive state is adopted .

  As shown in the time charts of the main parts in FIG. 5 and FIG. 8B, the three-stage switching drive state is a single suction by the high-speed suction operation of the first stage in the reverse driving process, and the subsequent second stage. The high-speed suction operation maintains or sucks up the chemical solution e, which is about to drip from the tip of the nozzle 33, into the nozzle 33, and the subsequent third-stage low-speed suction operation prevents dripping without generating bubbles or forming a thin film. That's it. Note that “medium speed” in the medium-speed suction operation is a speed slower than the high-speed suction and faster than the low-speed suction. In this way, by setting the reverse drive state (reverse drive process) in which the suction operation is performed by three-stage switching from high speed → medium speed → low speed, the first stage suction speed is set to “substantially high speed” to surely prevent liquid dripping. However, it is possible to realize a liquid pump system that can completely prevent unexpected liquid dripping from the nozzle 33 after the discharge operation while preventing generation of bubbles and thin film formation.

  Since no dust generation source, that is, any fluid equipment is installed downstream of the filter 32 in the liquid flow direction except for the nozzle 33, there is no possibility that dust is mixed into the chemical liquid discharged from the nozzle 33, and therefore a quality-accepting wafer. The yield of 34 improves. By moving the rolling diaphragm 3 of the pump device P in the suction direction without using the suck-back valve, a large-capacity suck-back operation that absorbs the pressure increase in the filter, which was impossible with the suck-back valve, is performed. be able to. The suckback speed and the suckback amount can be adjusted by setting the control means (a parameter in the pump controller) 38, and there is an advantage that manual adjustment of the suckback is unnecessary and labor is not required. In the present invention, it is possible to perform the suck-back operation with very high precision by precisely controlling the pump chamber volume change by motor drive. Thereby, the discharge amount can also be controlled with high accuracy.

  It should be noted that “... when switching from the discharge drive state to the reverse drive state, the pump device P immediately starts from the discharge operation in a state where the open state of the discharge side valve 28 and the closed state of the suction side valve 27 are maintained. “Immediately” in “It is configured to be switched to inhalation operation” means that the state of zero speed is not maintained, and in theory, the instantaneous speed is changed while switching from the positive speed to the negative speed. Excludes zero.

FIG. 9 is a block diagram embodying the suction side valve 27 and the discharge side valve 28 of the liquid pump system A and their operation systems, and FIG. 10 is a cross-sectional view showing the structure of the air operated valve.

That is, in the liquid body pump system A, the suction-side valve 27 and the discharge side valve 28, closed [Figure 10 the valve body 61 by moving the valve body 61 by means of an air is in contact with the valve seat 62 It is configured as an air operated valve that can be switched between an open state (see FIG. 10B) in which the valve body 61 is separated from the valve seat 62 (see (a)). The intake and discharge air supply and discharge passages 40 and 41 connect the control valve 39 for controlling the supply and discharge of air to the intake side valve 27 and the discharge side valve 28 and the intake side valve 27 and the discharge side valve 28. In addition, a suction side throttle means 42 that throttles the air passing through the suction side air supply / discharge path 40 and a discharge side throttle means 43 that throttles the air passing through the discharge side air supply / discharge path 41 are provided.

  Each of the throttle means 42 and 43 is a variable throttle means and is configured as a needle valve, and a control valve that controls supply and discharge of air (compressed air) from the air pump 63 to the needle valves 42 and 43 and the aspirator 35. Reference numeral 39 is a triple-type electromagnetic switching valve that is switch-controlled by the control device 38. That is, the suction side valve 27 and the discharge side valve 28 are configured to be opened and closed by the air pressure passing from the electromagnetic switching valve 39 through the suction side needle valve 42 or the discharge side needle valve 43.

  As shown in FIG. 10, the suction-side and discharge-side air-operated valves 27 and 28 have a pair of flow paths 51 and 52 having a common axis W, a valve body 61, a valve seat 62, and the like. A valve body 50 made of a fluororesin (PFA or the like), a piston 54 having a valve body 61 at its tip, an actuator portion 53 provided with a return spring 55, an air supply / discharge portion 56, a mounting plate 57, and each flow path 51. , 52 is provided with a pipe joint portion 58 or the like equipped for each. The first flow path 51 is formed with an annular path 51A having a longitudinal axis Z orthogonal to the flow path axis W at the end, and the end of the second flow path 52 in the longitudinal direction inside the circular path 51A. A passage 52A is formed concentrically, and a valve seat 62 is formed on the top surface of an annular partition wall 50A that partitions the annular passage 51A and the terminal longitudinal passage 52A.

  The valve body 61, which has a circular shape in the direction of the vertical axis Z, has a telescopic portion 61 a on the outer periphery thereof, and a synthetic resin (PPS etc.) casing 53 </ b> A of the actuator portion 53 on the outer periphery between the valve body 50. A diaphragm made of fluororesin (PTFE or the like) having a presser outer periphery 61b interposed and a fitting bar 61c screwed into a screw hole (not shown) at the tip of the piston 54 is configured. Air supply / discharge passages 40 and 41 made of a tube material or the like are connected to the air supply / discharge portion 56, and the first and second flow passages 51 and 52 are connected to the suction side flow passage 29, the suction portion 6 of the pump device P, and the discharge. The part 7 and the discharge side flow path 30 are connected in communication as appropriate. Reference numerals 53a and 59a are air vent holes. Moreover, the pipe joint part 58 which consists of the annular fluid supply / discharge port part 58a, the union nut 58b screwed to this, the inner ring 58c, etc. attaches to a well-known structure, and omits detailed description here.

  The opening / closing operation of the air operated valves 27 and 28 will be described. When air is not supplied to the air supply / exhaust portion 56 (exhaust state), the biasing force of the return spring 55 formed of a coil spring is shown in FIG. As a result, the piston 54 is pushed down, the valve body 61 comes into contact with the valve seat 62, and the annular path 51A and the terminal longitudinal path 52A are disconnected. When high-pressure air is supplied from the air supply / discharge portion 56 to the cylinder chamber 53S, the return spring 55 is moved until the piston upper end surface 54a contacts the lower end surface 59b of the lid case 59, as shown in FIG. The piston 54 is moved upward against the urging force, and the valve body 61 is lifted and separated from the valve seat 62 by a predetermined distance so that the first flow path 51 and the second flow path 52 communicate with each other.

  In order to improve the opening / closing response of the valve, the lift amount r (see FIG. 10B) of the valve body 61 is preferably reduced, but a sufficient flow rate (flow rate per unit time) for the valve open state is set. Since a certain value (= r) is necessary for securing, it cannot be made too small. Therefore, it is conceivable to improve the responsiveness by increasing the moving speed of the valve body 61. For that purpose, the return spring 55 is made strong with a high spring constant, and the air pressure for opening the valve is overcome. It will be set high. Therefore, in the air operated valves 27 and 28, the valve body 61 instantaneously moves back and comes into contact with the valve seat 62 as air is released (air exhaust), so that the rapid return movement of the valve body 61 is a kind of pump. Thus, the liquid level of the nozzle 33 may be slightly extruded. This is the aforementioned rebound phenomenon.

  As shown in FIG. 11, the needle valves 42 and 43 are a pair of supply / discharge passages 45 and 46 that are opposed to each other with a common axis X, and a ring that has a vertical axis Y perpendicular to the axis X. A guide case 47 having a shape, a valve body 44 made of synthetic resin that accommodates the supply / discharge passages 45 and 46 and a guide case 47 made of brass, a needle 48 made of brass, a lock nut 49, and the like. The lower end portion 47A of the guide case 47 is hermetically fitted into the ring partition wall portion 44A of the valve body 44 via the seal ring 60, and the first end passage 45a and the second supply passage 45 of the first supply / exhaust passage 45 are arranged vertically above and below the guide case 47. The second end passage 46a of the discharge passage 46 is formed so as to be distributed.

  The needle 48 is screwed into an upper end portion of a guide case 47 that is integrally incorporated in the valve body 44, and can be moved up and down with respect to the guide case 47 by rotating the knob 48A. The operation can be maintained at the appropriate vertical position by the operation 49. In the center hole 44a of the ring partition 44A, a tapered tip needle 48N having a needle 48A having a knob 48A at the upper end is inserted, and has a steeper taper angle above the tip needle 48N. A stop portion 48s is formed.

  In other words, the knob 48A is turned clockwise to move the needle 48 downward, and the central hole 44a is closed by the stop portion 48s, the valve is closed. And a ring-shaped fluid passage (not shown) is formed between the center hole 44a and the tip needle 48N so that the throttle is effective and the first end passage 45a and the second end passage 46a communicate with each other. can do. Then, as the amount of increase of the needle 48 is increased, the area of the fluid passage is increased and the restriction can be loosened. That is, the needle valves 42 and 43 are variable throttle valves that can variably set the throttle effect (throttle amount) by turning the knob 48A.

  Next, an inconvenience newly occurring in the liquid pump system shown in FIG. 1 and the like will be described. When the discharge-side air operated valve 28, which is the discharge-side valve of the pump device P, is closed after the suck-back process is finished, the liquid level of the sucked chemical solution e may drop again in the nozzle 33 due to the rebound phenomenon described above. is there. That is, as shown in FIG. 12, the liquid level is sucked to the height H from the lower end of the nozzle 33 by the suck back operation, and the height H is a degree of pulling up in anticipation of the re-lowering amount h due to the rebound phenomenon. Is set. Therefore, even if the rebound phenomenon occurs, since H> h, the liquid level of the chemical solution e that has been lowered again like the nozzle 33 shown by the broken line should still be located above the lower end of the nozzle (that is, OK!). It is.

  However, in some cases, due to the closing operation of the discharge side valve 28 (abrupt return movement of the valve body), the chemical solution e sucked up to the height H is lowered again more than expected and follows the path of the imaginary line marked with x. As shown in the nozzle situation (nozzle 33 drawn with upper and lower brackets on the rightmost side of the paper in FIG. 12), bubbles are mixed or liquid is discharged from the nozzle 33 due to the closing operation of the discharge side air operated valve 28. There was a risk of it occurring. This is a new problem due to the use of an air operated valve with excellent responsiveness as the discharge side valve 28.

  Therefore, a means for solving the new problem is to insert needle valves 42 and 43 between the electromagnetic control valve 39 and the air operated valves 27 and 28. That is, as shown in FIG. 13, by supplying air that has passed through needle valves 42 and 43, which are variable throttle valves, to the air operated valves 27 and 28 on the suction side and the discharge side, as shown in FIG. The valve opening action to the valve seat 62 of the valve body 61 due to the closing operation of the discharge side air operated valve 28 after the back operation is not changed, and the moving speed is controlled to be slow so that the adverse effect due to the pump action is eliminated or substantially eliminated, The adverse effects due to the rebound phenomenon disappear or almost disappear. As depicted on the upper side of the sheet of FIG. 13, even if a slight rebound phenomenon occurs, the liquid level re-lowering amount of the chemical solution e is smaller than the re-lowering amount h at the time of inconvenience shown in FIG. Therefore, drastically small d (d << h) is sufficient, and unexpected dripping is prevented.

  In addition, since the re-lowering amount is reduced, as shown in the order indicated by the phantom line arrows on the lower side of the sheet of FIG. It is also possible to further improve the responsiveness of the system while preventing new problems caused by using the air operated valves 27 and 28 from occurring.

  In FIG. 9, the suction side valve 27 is also configured as an air operated valve, and the suction side needle valve 42 is interposed, so that the adverse effect of the rebound phenomenon of the suction side air operated valve 27 does not occur. However, if only the purpose of eliminating the dripping from the nozzle 33 is sufficient, the suction side needle valve 42 can be omitted.

[Reference Example]
The rolling diaphragm pump 70 may be configured as a double rolling diaphragm pump including a second rolling diaphragm 71 instead of the O-ring 23 and the slipper ring 24 as shown in FIG. That is, a second rolling diaphragm 71 having an outer peripheral portion 71d supported by the cylinder 1 through an inner peripheral portion 71b supported by the piston 2 and a folded portion 71c on the outer periphery of the piston is provided on the side opposite to the pumping chamber of the rolling diaphragm 3. This is a pump 70 having a decompression chamber 26 surrounded by a cylinder 1, a piston 2, a rolling diaphragm 3 and a second rolling diaphragm 71.

  The cylinder 1 includes a front end cylinder portion 1A on the cylinder head 1a side and a base end cylinder portion 1B on the linear actuator 8 side, and a ring of the second rolling diaphragm 71 is interposed between the two 1A and 1B via an O-ring 72. The portion 71e is sandwiched and supported. The piston 2 is formed by screwed integration of a front end piston portion 2A for screwing the first rolling diaphragm 3 and a base end piston portion 2B screwed to the output screw shaft 18, both of which are 2A, The inner ring portion 71a of the second rolling diaphragm 71 is sandwiched and supported via an O-ring 73 between 2B.

  The second rolling diaphragm 71 includes an annular inner ring portion 71a, an inner peripheral portion 71b along the outer peripheral surface of the tip piston portion 2A, a turn-up portion 71c, and an outer peripheral portion 71d along the inner peripheral surface of the tip cylinder portion 1A. And the ring portion 71e. The folded portion 71c of the second rolling diaphragm 71 is folded so as to protrude toward the decompression chamber 26 in the direction along the axis (pump axis) C in the reciprocating direction of the piston 2. Due to the configuration in which the first and second rolling diaphragms 3 and 71 and the annular decompression chamber 26 are provided, the outer diameter of the piston 2 is set to be sufficiently smaller than the inner diameter of the cylinder 1.

  In the double rolling diaphragm pump 70, a piston 2 is accommodated in the cylinder 1 so as to be movable in the direction of the axis C, and the piston 2 is reciprocated by the above-described pump drive source and rotation preventing means. As described above, the straight cylinder-like piston 2 is divided into the distal piston portion 2A and the proximal piston portion 2B at the intermediate portion near the proximal end in the moving direction, as described above, and the distal piston portion 2A has the first rolling diaphragm. 3 includes a distal end cylindrical portion 2b for receiving and screwing the three screw shaft portions 3a, a solid cylindrical base end portion 2a, and a protruding screw portion 2c. The proximal piston portion 2B is formed to include a support portion 2d for screwing the output screw shaft 18 and an abutting tube portion 2e having an inner peripheral portion with a female screw 2f screwed to the protruding screw portion 2c. Yes.

  The first rolling diaphragm 3 that defines the pump chamber 4 with the cylinder head 1a includes a screw shaft portion 3a, a flange portion 3b, an inner peripheral portion 3c, an outer peripheral portion 3e, a ring portion 3f, and a head 3g. It is formed. The screw shaft portion 3a is screwed into a screw hole 2g formed coaxially with the shaft center C in the tip tube portion 2b of the tip piston portion 2A. The flange portion 3 b is formed so as to protrude in the radial direction from the outer peripheral surface at one end on the head side of the screw shaft portion 3 a, and is closely bonded to the outer edge portion of the tip end surface 2 b of the piston 2. The diaphragm inner peripheral portion 3c extends in the axial direction from the end portion of the flange portion 3b along the outer peripheral surface of the front end portion 2b of the piston 2 and is in close contact with the outer peripheral surface of the front end portion of the front end portion 2b of the piston 2. It is a shape.

  In the first rolling diaphragm 3, the outer peripheral portion 3 e extends in the axial direction from the end of the inner peripheral portion 3 c through the U-shaped folded portion 3 d along the inner peripheral surface on the cylinder head side of the cylinder 1. The thin film is in close contact with the inner peripheral surface of the cylinder portion 1A. The ring portion 3f extends in the radial direction from the end portion of the outer peripheral portion 3e, and is sandwiched between the tip cylinder portion 1A and the cylinder head (pump head) 1a. The head portion 3g is provided so as to protrude from one end surface of the screw shaft portion 3a on the head side, and a two-face notch structure for fitting a tool such as a wrench when the screw shaft 3a is screwed into the screw hole 2g. May be formed.

  An O-ring 5 made of fluoro rubber as a seal member is provided between the joint surfaces of the cylinder 1 and the ring portion 3f, and the space between the joint surfaces of the cylinder head 1a and the ring portion 3f is formed in the cylinder head 1a. The lip seal portion (not shown) is sealed against the surface of the ring portion 3f. In FIG. 15, the state when the piston 2 moves to the stroke end position in the discharge process, that is, the top dead center position J is the upper side of the axis C, and the piston 2 is the stroke end position in the suction process. That is, the state when moving to the bottom dead center position K is drawn on the lower side of the axis C in the drawing.

Schematic diagram showing the liquid pump system Side view of partly cutout showing the internal structure of the pump Sectional view showing the rolling diaphragm pump and its drive structure Sectional drawing which shows the pump discharge operation completion state of FIG. Time chart showing the operating status of the liquid pump system The reverse drive process with only one stage of high-speed suction is shown, (a) is the action diagram, (b) is the main part of the time chart of the pump position and pump speed. Process diagram showing the predicted action and actual action by reverse drive process of high / low two-stage switching (A) is a time chart diagram of the pump position and pump speed before and after the reverse drive process of FIG. 7, (b) is a time chart diagram of the main part in the reverse drive process of three-stage switching. Schematic diagram embodying the suction side valve and the discharge side valve and its operation system of the liquids pumping system The structure of the air operated valve is shown, (a) is a sectional view in a valve open state, (b) is a sectional view in a valve closed state. Sectional view showing the structure of the needle valve Action diagram showing inconvenient behavior of nozzle liquid level with closing operation of discharge side valve Action diagram of the main part showing the improvement status of the nozzle liquid level by the system of FIG. Plan view at a predetermined height showing the internal structure of the pump Reference diagram showing the structure of a double rolling diaphragm pump

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 3 Rolling diaphragm 3c Inner peripheral part 3d Folding part 3e Outer peripheral part 4 Pump chamber 6 Suction part 7 Discharge part 21 Position detection means 25 Pressure-reduction channel 26 Pressure-reduction chamber 27 Suction side valve 28 Discharge side valve 29 Suction side flow Passage 30 discharge side passage 35 pressure reducing means 39 control valve 41, 40 air supply / discharge passage
43 Throttle means 61 Valve body 62 Valve seat 70 Rolling diaphragm pump 71 Second rolling diaphragm 71b Inner peripheral portion 71c Folded portion 71d Outer peripheral portion control means 77 Control means
A Liquid pump system C
P Pump device V Check valve

Claims (4)

A cylinder, a piston housed in the cylinder and driven and reciprocated, a rolling diaphragm having an outer peripheral portion supported by the cylinder via an inner peripheral portion supported by the piston and a folded portion of the outer periphery of the piston; A pump chamber which is partitioned by a rolling diaphragm and whose volume is changed by movement of the piston; and a decompression chamber which is surrounded by the cylinder, the piston and the rolling diaphragm on the back side of the rolling diaphragm. A rolling diaphragm pump, a discharge side valve for opening and closing a discharge side flow path for the rolling diaphragm pump, and a suction side valve for opening and closing a suction side flow path for the rolling diaphragm pump, and the discharge side valve And close the suction A suction drive state in which the rolling diaphragm pump is inhaled by opening the side valve, and the discharge side valve is opened, and the suction valve is closed to cause the rolling diaphragm pump to perform a discharge operation. A liquid pump system configured to be switchable between discharge driving states,
When switching from the discharge drive state to the suction drive state, with the end of the discharge drive state, the discharge side valve is opened and the suction side valve is closed so that the rolling diaphragm pump is It is switched to the suction drive state through the reverse drive state for inhalation operation,
When switching from the discharge drive state to the reverse drive state, the rolling diaphragm pump starts from the discharge operation while the open state of the discharge side valve and the closed state of the suction side valve are maintained. It is configured to be immediately switched to the inhalation operation,
The discharge side valve and the suction side valve are in a closed state in which the valve body is in contact with the valve seat by moving the valve body using air, and in a valve open state in which the valve body is separated from the valve seat It is configured as an air operated valve that can be switched between
A control valve for controlling air supply / discharge to the discharge side valve and the suction side valve, a discharge side and a suction side air supply / discharge path connecting the discharge side valve and the suction side valve are provided, and the discharge side A throttling means for throttling the air passing through the air supply / discharge path is provided,
The decompression means for decompressing the decompression chamber, and a fluid suction part and a discharge part each communicating with the pump chamber, and the decompression means and the decompression chamber are allowed to decompress the decompression chamber. And the pressure increasing operation of the decompression chamber is communicated via a check valve for blocking ,
The suction operation of the rolling diaphragm pump in the reverse drive state is a high-speed suction operation immediately after switching from the discharge operation, a medium-speed suction operation following the high-speed suction operation, and a low-speed following the medium-speed suction operation A liquid pump system that is set to a three-stage switching drive state by suction operation . A pump apparatus comprising the liquid pump system according to claim 1. Control means for ending the pressure reducing operation of the pressure reducing means before the start of the discharge operation in which the piston moves from the bottom dead center position where the pump chamber volume is maximum toward the top dead center position where the pump chamber volume is minimum. The liquid pump system according to claim 1 or the pump device according to claim 2, which is equipped. The pressure reducing means of the liquid pump system according to claim 1 or the pump device according to claim 2, wherein the pressure reducing operation has a top dead center at which the pump chamber volume is minimized from a bottom dead center position at which the pump chamber volume is maximized. A method of controlling a rolling diaphragm pump that is driven so as to be finished before the start of a discharge operation in which the piston moves toward a position.

Images