JP2010106674A - Pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a pump having long service life which can be easily manufactured and which is excellent in assemblability, maintainability and responsiveness. <P>SOLUTION: In a pump 1, the inside of a cylinder 20 is partitioned into a pump chamber 50 for sucking and discharging liquid and a drive chamber 60 for accommodating a reciprocating member 30 by a diaphragm 10. The reciprocating member 30 is brought into butting-contact with the diaphragm 10 so as to be separable therefrom. Pressure P2 in the drive chamber 60 is always kept lower than pressure P1 in the pump chamber 50 (P2<P1). The pressure difference P3 (P1-P2) therebetween is also always kept not lower than a prescribed pressure. Thus, the diaphragm 10 is operated in accordance with the motion of the reciprocating member 30 to eliminate the coupling therebetween. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pump used for supplying a liquid, and more particularly to a pump used for supplying a chemical solution during an FPD manufacturing process of a semiconductor, liquid crystal or the like.

In this type of conventional pump, the inside of a cylinder is partitioned by a diaphragm into a pump chamber that sucks and discharges liquid and a drive chamber that houses a reciprocating member, and the diaphragm and the reciprocating member are coupled by fastening to reciprocate the diaphragm. The pump is operated in accordance with the movement of the moving member, the liquid is sucked into the pump chamber in the suction process in which the volume of the pump chamber is expanded, and the liquid in the pump chamber is discharged in the discharge process to be reduced (Patent Document 1).
JP-A-9-53566

  When the diaphragm and the reciprocating member are joined by fastening or other fittings as in the conventional pump, a center shift occurs between the diaphragm and the reciprocating member depending on the processing accuracy of the diaphragm and the reciprocating member. As a result, concentrated stress is generated in the diaphragm, and uneven wear occurs in the sliding portion arranged on the same axis as that of the reciprocating member, resulting in a problem that the pump life is reduced. Further, in the case of coupling by fastening, there is a problem that the assembling property and the maintenance property are deteriorated, and the pump response is also deteriorated due to screw backlash.

  The pump of the present invention for solving the above problems is a pump in which a cylinder 20 is partitioned by a diaphragm 10 into a pump chamber 50 that sucks and discharges liquid and a drive chamber 60 that houses a reciprocating member 30. The reciprocating member 30 is brought into contact with the diaphragm 10 at an angle of approximately 90 degrees so that the pressure P2 in the drive chamber 60 is always kept lower than the pressure P1 in the pump chamber 50 (P2 <P1), and The differential pressure is always maintained at a predetermined pressure or higher so that the diaphragm 10 is operated in accordance with the movement of the reciprocating member 30 and is installed in the cylinder 20 to maintain contact between the diaphragm 10 and the reciprocating member 30. The coupling between the diaphragm 10 and the reciprocating member 30 is eliminated while eliminating the urging member. At this time, the diaphragm 10 is formed of a fluororesin, the cylindrical outer peripheral portion 11 of the diaphragm 10 has flexibility, and the outer peripheral portion 11 passes through the folded portion 11 a and the flange portion 13 at the open end of the outer peripheral portion 11. The reciprocating member 30 is formed in a columnar shape, and the reciprocating member 30 is brought into contact with the closed end of the diaphragm 10 so as to be separated at an angle of approximately 90 degrees. It is preferable that 10 outer peripheral portions 11 are rolled by a gap between the two surfaces while being in close contact with the outer peripheral surface of the reciprocating member 30 and the inner peripheral surface of the cylinder 20. Further, it is preferable that the reciprocating member 30 has a passage 33 for communicating between the mutual contact surfaces of the reciprocating member 30 and the diaphragm 10 to the drive chamber 60.

  According to the present invention, since the coupling between the diaphragm 10 and the reciprocating member 30 is eliminated, the pump life can be improved, and the assembly, maintenance, and responsiveness of the pump can also be improved. Therefore, it is possible to obtain a long-life pump that can be easily manufactured and is excellent in assembling, maintenance, and responsiveness.

  Further, since the reciprocating member 30 has a passage 33 for communicating between the mutual contact surfaces of the reciprocating member 30 and the diaphragm 10 to the drive chamber 60, the reciprocating member 30 and the diaphragm 10 are in mutual contact when the pump is driven. The surface can be more closely adhered and held, and the diaphragm 10 can be operated more reliably in accordance with the movement of the reciprocating member 30, and the response performance, quantitative performance, constant flow performance, etc. of the pump can be more reliably exhibited. In addition, the air between the reciprocating member 30 and the diaphragm 10 can be extracted from the passage 33 during pump assembly, and the reciprocating member 30 and the diaphragm 10 can be easily brought into contact with each other without causing an overload on the diaphragm 10, While preventing the diaphragm 10 from being damaged, there is a remarkable effect that the assembling property of the pump can be further improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a pump according to an embodiment of the present invention.

  A pump 1 shown in FIG. 1 is a diaphragm pump for quantitatively supplying a chemical solution such as a resist solution used in a manufacturing process of an FPD such as a liquid crystal or a semiconductor at a constant flow rate. A diaphragm 10 to be used is a PTFE (polytetrafluoroethylene). A rolling diaphragm formed of a fluororesin such as (fluoroethylene) and imparted chemical resistance.

  First, the diaphragm 10 is formed in a substantially bottomed cylindrical shape (cup shape), and is a cylindrical outer peripheral portion (hereinafter referred to as a “rolling portion”) 11 that is folded (turned back) inside or outside at an intermediate portion. A folded portion 11a having a bending angle of about 180 degrees, and an inner peripheral portion 11b and an outer peripheral portion 11c extending in parallel in the axial direction from the inner peripheral side end and the outer peripheral side end of the folded portion 11a. ing. Moreover, it has the disk-shaped end plate part 12 which makes the edge part of the inner peripheral part 11b a closed end part, and the ring-shaped flange part 13 which stands up in the radial direction from the edge part of the outer peripheral part 11c. Further, the rolling portion 11 is formed in a thin film shape and has flexibility, and the end plate portion 12 and the flange portion 13 are formed thick and have rigidity. FIG. 1 shows a pulling type in which a rolling portion 11 is formed in an initial shape (shape at the time of pump assembly) in which the axial length of the outer peripheral portion 11c is shorter than the axial length of the inner peripheral portion 11b (pump operation starts from the suction step) The type of diaphragm 10 is shown.

  Thus, the pump 1 includes the diaphragm 10, a cylindrical cylinder 20 that is a pump housing that houses the diaphragm 10, a reciprocating member 30 that operates the diaphragm 10, and a reciprocating motion in the reciprocating member 30. And a pump drive source 40 such as a linear actuator. FIG. 1 shows a vertical pump 1 in which the axial center line CL of the cylinder 20 is vertical and the diaphragm 10 and the reciprocating member 30 are arranged on the vertical axial center line CL.

  The cylinder 20 having the vertical axis CL includes a cylindrical cylinder pipe 21, a headed cylindrical head cover 22 attached to the upper side of the cylinder pipe 21, and a rod cover 23 attached to the lower side of the cylinder pipe 21. It consists of and. The rod cover 23 is provided with a bearing portion 24, the head cover 22 is provided with a suction port 25 and a discharge port 26 through which inner and outer surfaces penetrate and discharge a chemical solution, and the cylinder pipe 21 is provided with a vent hole 27 through the inner and outer surfaces. . The bearing portion 24 and the discharge port 26 are disposed on the vertical axis CL, the suction port 25 is disposed at the lower part of the head cover 22, and the vent hole 27 is disposed at the lower part of the cylinder pipe 21. A chemical solution tank (not shown) is connected to the suction port 25 via a check valve (not shown), and the discharge port 26 is connected to a chemical solution supply unit (not shown) via a check valve (not shown). The check valve on the suction side allows the flow of the chemical solution from the tank to the suction port 25 and prevents the reverse flow. The check valve on the discharge side allows the flow of the chemical solution from the discharge port 26 to the chemical solution supply unit and prevents the reverse flow.

  The reciprocating member 30 disposed on the same axis as the cylinder 20 has a columnar piston 31 on the upper side and a columnar piston rod 32 that is longer than the piston 31 on the lower side. The piston 31 is accommodated in the cylinder 20, and the outer peripheral surface of the piston 31 is opposed to the inner peripheral surface of the cylinder 20 with a predetermined gap. In addition, a plurality of air passages 33 each having a linear elongated hole penetrating from the upper end surface of the piston 31 to the lower end surface are provided at equal intervals on the same circumference in the outer peripheral portion of the piston 31. The piston rod 32 is inserted into the bearing portion 24 of the cylinder 20 and supported so as to be slidable in the axial direction (vertical direction) on the vertical axis CL. In order to prevent leakage from the sliding portion, packings 28 such as O-rings are provided at two locations on the bearing portion 24 side of the sliding portion. The lower end portion of the piston rod 32 protrudes outside from the lower side of the cylinder 20, and the lower end portion of the piston rod 32 is disposed on the lower outer side of the cylinder 20 on the same axis as the cylinder 20. The output shaft of the pump drive source 40 and the vertical axis core line CL are coupled in a straight line, and a reciprocating motion in the axial direction is given to the lower end portion of the piston rod 32 from the output shaft of the pump drive source 40.

  FIG. 1 shows a reciprocating member 30 having a two-piece structure including the piston 31 and the piston rod 32. The reciprocating member 30 is provided with a circular recess 34 for positioning a relatively shallow piston 31 on the lower end surface thereof. The circular recess 34 is disposed on the vertical axis CL, and the upper end of the piston rod 32 disposed on the same axis as the cylinder 20 is fitted into the circular recess 34 from below. As a result, the piston 31 is supported from the lower side by the upper end surface of the piston rod 32 that is in contact with the center portion of the lower end surface of the piston 31 (the top surface of the circular recess 34). Is positioned substantially on the vertical axis CL on the outer peripheral surface of the upper end of the piston rod 32 facing each other with a small fitting gap. Here, the fitting between the circular concave portion 34 and the upper end portion of the piston rod 32 does not integrally combine the piston 31 and the piston rod 32. Therefore, if a force in the pulling direction is applied to the other while one of the piston 31 and the piston rod 32 is fixed during maintenance, the two are separated and separated.

  The diaphragm 10 is mounted in the cylinder 20 with the flange portion 13 being sandwiched between the joint surfaces of the cylinder pipe 21 and the head cover 22. In this attached state (pump assembly state), the outer peripheral portion 11c connected to the fixed end (flange 13) is in contact with the inner peripheral surface of the cylinder pipe 21 and is extended downward along the inner peripheral surface of the cylinder pipe 21. The folded portion 11 a is located on the inner peripheral side of the cylinder pipe 21, the inner peripheral portion 11 b connected to the end plate portion 12 is extended upward in parallel with the outer peripheral portion 11 c, and the end plate portion 12 is the top surface of the head cover 22. Opposite to the top in the vicinity. Thereby, the diaphragm 10 is accommodated on the vertical axis CL in the cylinder 20, and the inside of the cylinder 20 is above the diaphragm 10 communicating with the suction port 25 and the discharge port 26 by the diaphragm 10 (head cover 22 side). The pump chamber 50 and the drive chamber 60 that communicates with the vent hole 27 and that is lower than the diaphragm 10 that houses the reciprocating member 30 (on the rod cover 23 side).

  Further, in the drive chamber 60 below the cylinder 20, which is partitioned from the pump chamber 50 above the cylinder 20 by the diaphragm 10, the piston 31 provided on the top of the reciprocating member 30 extends from the lower side to the inner periphery of the rolling portion 10 of the diaphragm 10. The upper end surface of the piston 31 is in contact with the lower surface of the end plate portion 12 of the diaphragm 10 at an angle of approximately 90 degrees, that is, abutting contact. Thereby, the inner peripheral part 11b of the rolling part 11 contacts the outer peripheral surface of the piston 31, and the turned-up part 11a is located in the gap between the outer peripheral surface of the piston 31 and the inner peripheral surface of the cylinder pipe 21, and reciprocates with the diaphragm 10. The piston 31 of the member 30 is disposed on the same axis. That is, the diaphragm 10 and the piston 31 and the piston rod 32 of the reciprocating member 30 are disposed on the vertical axis CL in the cylinder 20. Here, the fitting between the rolling portion 10 of the diaphragm 10 and the piston 31 of the reciprocating member 30 does not integrally integrate the diaphragm 10 and the reciprocating member 30. Therefore, when a pulling force is applied to the other while fixing one of the rolling portion 10 of the diaphragm 10 and the piston 31 of the reciprocating member 30 during maintenance, the two are separated and separated.

  Further, the upper end surface of the piston 31 and the lower surface of the end plate portion 12 that are in abutting contact with each other are communicated with the drive chamber 60 by the plurality of air passages 33 provided in the piston 31.

  As described above, the pump 1 is divided into the pump chamber 50 that sucks and discharges the chemical solution and the drive chamber 60 that houses the reciprocating member 30 inside the cylinder 20 by the diaphragm 10, and the reciprocating member 30 projects against the diaphragm 10. They are just mated and touched but not joined. When the pump is driven, the pressure P2 in the drive chamber 60 is always kept lower than the pressure P1 in the pump chamber 50 (P2 <P1), and the differential pressure P3 (P1-P2) is always kept at a predetermined pressure or higher. Thus, the diaphragm 10 is configured to be operated in accordance with the movement of the reciprocating member 30. Here, the differential pressure P3 to be maintained tends to separate the lower surface of the end plate 12 that abuts and contacts the piston 31, the upper end surface of the piston 31 and the center of the lower end surface of the piston 31 that abuts and the upper end surface of the piston rod 32. The pressure is set to be equal to or higher than a predetermined pressure at which the axial force can be overcome and securely held in close contact. Considering the pump performance and the hardness of the rolling part 11 of the diaphragm 10 made of a fluororesin, the predetermined pressure may cause the contact surfaces that come into contact with each other to be separated at less than 50 KPa, and may be separated at 50 KPa or more. Therefore, it is preferable to set the pressure to 50 KPa or more.

  Further, when the pressure P2 in the drive chamber 60 is always kept lower than the pressure P1 in the pump chamber 50, and the differential pressure P3 is always maintained at a predetermined pressure (50 KPa) or more, a positive pressure is applied to the pump chamber 50 side. In FIG. 1, a vacuum pump, a vacuum generator, or the like connected to the vent 27 of the cylinder 30 communicating with the drive chamber 60 to make the drive chamber 60 have a negative pressure is added. The differential pressure forming means 70 is shown. In this case, the pressure P2 in the drive chamber 60 is kept constant at a set pressure (negative pressure) that does not drop below a predetermined pressure even if the differential pressure P3 varies according to the variation of the pressure P1 in the pump chamber 50. Alternatively, the pressure P2 in the drive chamber 60 may be automatically adjusted according to the fluctuation of the pressure P1 in the pump chamber 50, and the differential pressure P3 may be kept constant at a set pressure equal to or higher than a predetermined pressure.

  On the other hand, a differential pressure forming means (not shown) for applying a positive pressure to the pump chamber 50 side is a chemical solution pressurizing pump installed on the upstream side of the suction side check valve connected to the suction port 25 of the cylinder 20 and the cylinder 20. A throttle valve for holding the pressure in the pump chamber can be configured upstream or downstream of the discharge-side check valve connected to the discharge port 26.

  When a very large differential pressure P3 is required, the combined use of the differential pressure forming means 70 that makes the drive chamber 60 a negative pressure and the differential pressure forming means that applies a positive pressure to the pump chamber 50 side is not hindered.

  In the pump 1, it is preferable that the head cover 22 of the cylinder 20, which is a liquid contact part other than the diaphragm 10, is made of a fluororesin such as PTFE and has chemical resistance similarly to the diaphragm 10.

  Next, the operation of the pump 1 configured as described above will be described with reference to FIG.

  Since the pump 1 shown in FIG. 1 incorporates a pulling type diaphragm 10, when the pump drive source 40 is operated and driven, the piston rod 32 starts up and down reciprocating from a downward backward movement. The pressure P2 in the drive chamber 60 is always kept lower than the pressure P1 in the pump chamber 50 by the differential pressure forming means 70 when the pump is driven, and the differential pressure P3 is always maintained at a predetermined pressure or higher. Since the lower end surface center portion of the piston 31 is held in close contact (adsorption) with the upper end surface of 32, and the lower surface of the end plate portion 12 of the diaphragm 10 is held in close contact (adsorption) with the upper end surface of the piston 31, the piston rod When 32 moves backward, the piston 31 and the end plate portion 12 of the diaphragm follow the backward movement of the piston rod 32 and move backward downward. That is, the reciprocating member 30 and the end plate portion 12 of the diaphragm 10 are moved backward together. In this suction process, the rolling portion 11 of the diaphragm 10 has a shorter axial length of the inner peripheral portion 11b and a longer axial length of the outer peripheral portion 11c, and the inner peripheral surface of the cylinder pipe 21 and the outer periphery of the piston 31. The folded portion 11a rolls while being displaced downward in the gap with the surface, and accordingly, the volume of the pump chamber 50 is expanded, and the chemical liquid in the liquid tank is sucked into the pump chamber 50 in the process.

  Further, when the piston rod 32 moves upward, the lower end surface central portion of the piston 31 is pushed up from the lower side by the upper end surface of the piston rod 32, and at the same time, the lower surface of the end plate 12 of the diaphragm 10 is lowered by the upper end surface of the piston 31. The end plate of the piston 31 and the diaphragm 10 is pushed up from the side and the upper end surface of the piston rod 32, the center portion of the lower end surface of the piston 31 and the upper end surface of the piston 31 and the lower surface of the end plate portion 12 of the diaphragm 10 are held in close contact. The portion 12 follows the forward movement of the piston rod 32 and moves upward. That is, the reciprocating member 30 and the end plate portion 12 of the diaphragm 10 move forward integrally. In this discharge process, the rolling portion 11 of the diaphragm 10 has an axial length of the inner peripheral portion 11b that is longer, an axial length of the outer peripheral portion 11c that is shorter, an inner peripheral surface of the cylinder pipe 21, and an outer periphery of the piston 31. The folding portion 11a rolls while being displaced upward in the gap with the surface, and accordingly, the volume of the pump chamber 50 is reduced, and in this process, the liquid in the pump chamber 50 is discharged and supplied to the chemical solution supply portion. .

  As described above, when the diaphragm 10 is operated in accordance with the movement of the reciprocating member 30, the liquid in the liquid tank is supplied to the chemical liquid supply unit at a constant and constant flow rate.

  Then, the pump 1 operates the diaphragm 10 in accordance with the movement of the reciprocating member 30 as described above, and connects the diaphragm 10 and the reciprocating member 30 by fastening when supplying the liquid at a constant and constant flow rate. In addition, since the coupling between the diaphragm 10 and the reciprocating member 30 caused by such coupling is eliminated, the stress concentration on the folded portion 11a of the rolling portion 11 caused by the center deviation is eliminated. Since the uneven wear of the packing 28 arranged on the same axis as the reciprocating member 30 is eliminated, the pump life is improved. In addition, the assembly, maintenance, and responsiveness of the pump 1 are improved. Further, since an urging member incorporated in the cylinder 20 such as a spring that keeps the diaphragm 10 and the reciprocating member 30 in contact with each other is not necessary, the assemblability of the pump 1 is greatly improved.

  Further, since the space between the upper end surface of the piston 31 and the lower surface of the end plate 12 of the diaphragm 10 communicated directly with the drive chamber 60 by the air passage 33 provided in the piston 31, the pump 1 is driven. The pressure difference P3 between the pressure P2 in the drive chamber 60 and the pressure P1 in the pump chamber 50 causes the upper end surface of the piston 31 and the lower surface of the end plate portion 12 of the diaphragm 10 to be held in close contact with each other, thereby reciprocating the diaphragm 10. The pump 30 can be operated more reliably in accordance with the movement of the pump 30, and the pump response performance, quantitative performance, constant flow performance, etc. can be more reliably exhibited. Overloading the rolling part 11 of the diaphragm 10 with the piston 31 and the diaphragm 10 while venting the air between the diaphragms 10 The pump 1 can be smoothly fitted without being generated, and the upper end surface of the piston 31 and the lower surface of the end plate portion 12 of the diaphragm 10 can be brought into contact with each other, thereby preventing the diaphragm 10 from being damaged and improving the assembly of the pump 1. It can be improved.

  As mentioned above, although this Embodiment showed one suitable embodiment of this invention, this invention is not limited to it, A various change can be implemented within the range which does not deviate from the summary.

  For example, although the vertical diaphragm pump 1 is shown in the present embodiment, the present invention is a horizontal type in which the axial center line of the cylinder 20 is horizontal and the diaphragm 10 and the reciprocating member 30 are arranged on the horizontal axial center line. It can be suitably implemented also for a diaphragm pump. Moreover, although the diaphragm pump 1 using the pulling type rolling diaphragm 10 is shown in the present embodiment, the present invention has an initial shape in which the axial length of the outer peripheral portion 11c is longer than the axial length of the inner peripheral portion 11b (pump The present invention can also be suitably applied to a diaphragm pump that uses a rolling diaphragm of a push type (a pump operation starts from a discharge process) in which a rolling portion 11 is formed in the shape at the time of assembly.

  Further, in the present embodiment, a reciprocating drive member 30 having a two-piece structure including a piston 31 and a piston rod 32 and having a positioning circular recess 34 into which the upper end of the piston rod 32 is fitted is used. As shown in FIG. 2 (A), the present invention is a two-piece structure comprising a piston 31 and a piston rod 32, and a small cylindrical positioning is provided at the center of the lower end surface of the piston 31. The reciprocating drive member 30A is provided with a positioning protrusion 31A and a positioning circular recess 34A for fitting the protrusion 31A into the center of the upper end surface of the piston rod 32 from above, that is, the reciprocating driving member 30 shown in FIG. Also suitable for a diaphragm pump using a reciprocating drive member 30A in which the concavity and convexity of the fitting portion between the piston rod 32 and the piston rod 32 are reversed. Can Hodokosuru. Further, as shown in FIG. 2B, the present invention can also be suitably implemented in a diaphragm pump using a one-piece reciprocating drive member 30B in which a piston 31 and a piston rod 32 are integrally formed.

  In addition, the present invention can be suitably implemented in a diaphragm pump in which the liquid to be supplied and the material and form of the diaphragm to be used are different from those of the present embodiment.

It is sectional drawing of the pump which concerns on one embodiment of this invention. FIG. 2 is a partial view showing a modified structure of part A in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pump 10 Diaphragm 11 Rolling part 11a Folding part 11b Outer peripheral part 11c Inner peripheral part 12 End plate part 13 Flange part 20 Cylinder 30 Reciprocating member 31 Piston 32 Piston rod 33 Air passage 50 Pump chamber 60 Drive chamber 70 Differential pressure formation means

Claims (3)

  The cylinder is divided into a pump chamber that sucks and discharges liquid by a diaphragm and a drive chamber that houses a reciprocating member, and the reciprocating member contacts the diaphragm so as to be separated at an angle of approximately 90 degrees. The pressure in the driving chamber is always maintained lower than the pressure in the pump chamber, and the differential pressure is always maintained at a predetermined pressure or higher, so that the diaphragm is operated in accordance with the movement of the reciprocating member. pump.   The diaphragm is made of fluororesin, the cylindrical outer periphery of the diaphragm is flexible, the outer periphery passes through the folded portion, and has a flange at the open end of the outer periphery, and the flange is attached to the cylinder The reciprocating member is formed in a columnar shape, the reciprocating drive member is detachably contacted with the closed end of the diaphragm at an angle of approximately 90 degrees, and the outer periphery of the diaphragm is connected to the outer peripheral surface of the reciprocating member and the inner periphery of the cylinder The pump according to claim 1, wherein the pump is rolled in a gap between the two surfaces while being in close contact with the surface.   The pump according to claim 1 or 2, wherein the reciprocating member has a passage for communicating between the contact surfaces of the reciprocating member and the diaphragm to the drive chamber.

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