JP2011032873A - Bellows pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bellows pump improved so as to prevent a disadvantageous phenomenon of a hole being opened in a bellows due to discharge caused by electrification of static electricity by preventing electrification in a pump interior. <P>SOLUTION: The bellows pump has a pump body 1 including a suction passage 12 and a discharge passage 13 of a chemical, a bellows 2 disposed in a state of forming a sealed space 11 with the pump body 1 with one end air-tightly fixed to the pump body 1, an operation part 15 provided in another side of the bellows 2 to extend and contract the bellows 2 with respect to the pump body 1, a suction valve 6 provided in the suction passage 12 communicated with the sealed space 11, and a discharge valve 7 provided in the discharge passage 13 communicated with the sealed space 11. It includes a current collecting member C made of a conductive material facing the sealed space 11, and a conductive means D with one end conductively connected to the current collecting member C and having another end facing an exterior of the pump body 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bellows pump suitable as a pure water and chemical solution feeding means used in semiconductor and liquid crystal manufacturing facilities and apparatuses.

  The bellows pump includes a pump body having a suction passage and a discharge passage for a fluid to be transferred, a bellows disposed in a state in which one end is hermetically fixed to the pump body and a sealed space is formed between the pump body and the bellows. An operating portion provided on the other end side of the bellows to expand and contract with respect to the pump body, a suction valve provided in a suction path communicating with the sealed space, and a discharge valve provided in the discharge path communicating with the sealed space It is configured. As an example of such a bellows pump, a single cylinder type shown in Patent Document 1 and a double cylinder type (reciprocating pump) shown in Patent Document 2 are known.

  Since a chemical solution used in a semiconductor manufacturing apparatus or the like is required to be pure, a bellows pump is used to avoid contamination when the chemical solution passes through the pump. A relatively pure fluororesin such as PTFE or PFA is used as a component member of the liquid contact part in the bellows pump, that is, a liquid contact member. These fluororesins have a very high electrical insulating property and are therefore easily charged.

  On the other hand, some chemicals used for semiconductor manufacturing have low conductivity. When transporting chemicals with low electrical conductivity by the bellows pump, which uses the fluororesin described above for the wetted parts, the static electricity generated by friction due to the flow of the chemicals on the wetted surface will exceed the insulation limit on the wetted surface. When charged, a discharge eventually occurs. The discharge has a very high voltage, and a very large discharge current passes through the fluororesin wetted member, which may cause a phenomenon of opening a hole in the wetted member.

  When the inconvenient phenomenon that the hole by this discharge is formed occurs in the bellows among the wetted parts of the bellows pump, the hole is opened in the bellows, which causes the leakage of the chemical (the liquid to be sealed). is there.

JP 2001-123959 A JP 2002-174180 A

  The object of the present invention is to prevent charging inside the pump by devising the structure and material so as to prevent the above-mentioned problem, that is, the inconvenient phenomenon that a hole is opened in the bellows due to discharge due to electrostatic charging. The present invention is to provide an improved bellows pump.

According to the first aspect of the present invention, a sealed space 11 is provided between a pump body 1 having a suction passage 12 and a discharge passage 13 for a fluid to be transferred and one end of the pump body 1 that is airtightly fixed to the pump body 1. The bellows 2 provided in a state of forming the bellows, the operating portion 15 provided on the other end side of the bellows 2 to extend and contract the bellows 2 with respect to the pump body 1, and the communication with the sealed space 11 In the bellows pump having the suction valve 6 provided in the suction path 12 and the discharge valve 7 provided in the discharge path 13 communicating with the sealed space 11,
A current collecting member C made of a conductive material facing the sealed space 11 and conductive means D having one end connected to the current collecting member C and having the other end facing the outside of the pump body 1 are provided. It is characterized by being.

  The invention according to claim 2 is the bellows pump according to claim 1, wherein the suction valve 6 and the discharge valve 7 are supported by the pump body 1 in a state of facing the sealed space 11, and the suction valve 6 and / or Alternatively, casings 6A and 7A of the discharge valve 7 are screwed to the pump body 1, the current collecting member C is the metal casings 6A and 7A, and the conductive means D is the metal. It is a pump body 1.

  The invention according to claim 3 is the bellows pump according to claim 2, wherein the casings 6a and 7a and the pump body 1 are made of stainless steel.

  According to a fourth aspect of the present invention, in the bellows pump according to the first aspect, the current collector C is a metal bar that is implanted in the pump body 1 with the tip portion facing the sealed space 11. 26, and the conductive means D is a conductive member 27 that is conductively connected to the rod member 26 and faces the outside of the pump body 1.

  According to a fifth aspect of the present invention, in the bellows pump according to the fourth aspect, a plurality of the bar members 26 are provided around the axis P in the expansion and contraction direction of the bellows 2. A current collecting ring 28 that is conductively connected to the distal end portion is provided.

  According to the first aspect of the present invention, static electricity generated by friction due to the flow of a fluid to be transferred such as a chemical solution on the liquid contact surface can be taken out of the pump through the current collecting member and the conductive means. It is possible to prevent static electricity from being charged in the sealed space and to prevent discharge due to the charging. As a result, the bellows pump is improved by devising the structure and materials so that charging does not occur inside the pump, and the inconvenience of opening holes in the bellows due to discharge due to electrostatic charging is prevented. can do.

  According to the invention of claim 2, the means for taking out static electricity is constituted by the essential components that the current collecting member is the casing of the intake valve and / or the discharge valve and the conductive means is the pump body. There is an advantage that the effect of the invention of Item 1 can be obtained at low cost with little modification. In this case, if the casing and the pump body are made of stainless steel and have both high corrosion resistance and high conductivity, the bellows pump can be made more desirable.

  According to the invention of claim 4, by providing a metal bar and a conductive member that is conductively connected to the bar and faces the outside of the pump body, the conventional constituent members can be used as they are and economically claimed. The bellows pump which can acquire the said effect by 1 invention can be provided.

  According to the invention of claim 5, an advantage that the effect of the invention of claim 4 can be exhibited more efficiently can be obtained by providing a plurality of bar members and a current collecting ring over them.

Half sectional view showing the structure of a compound cylinder bellows pump (Example 1) Enlarged sectional view showing pump structure on one side The partial top view which shows the discharge side part in FIG. External view of bellows pump with metal fitting on the discharge side Schematic diagram of bellows pump showing static eliminating means by another structure (Example 2) Schematic of bellows pump showing other static elimination means of another structure (Example 3)

  Hereinafter, embodiments of a bellows pump according to the present invention will be described with reference to the drawings, taking a double cylinder type as an example.

[Example 1]
As shown in FIGS. 1 and 2, the bellows pump A according to the first embodiment has a structure in which a pair of bellows are combined in a back-to-back state, that is, a multi-cylinder type, and has a large discharge amount per unit time. It is a large capacity pump that can be taken. The bellows pump A is a pair of stainless steel made of a central pump body 1 and a fluororesin (such as PTFE) disposed on the left and right (both ends) of the pump body 1 and having a common shaft center (pump shaft) P. Bellows 2, 2, a pair of air cylinders 3, 3, a pair of intermediate cases 4, 4 made of PP resin connected to the left and right of the pump body 1, and an aluminum connected to the left and right outer sides of each intermediate case 4 A pair of end cases 5 and 5 made of an alloy or the like, each pair of intake check valves 6 and 6, discharge check valves 7 and 7, a pair of proximity sensors 8 and 8, and the like are configured. .

  Here, the pumping action will be briefly described. Air is supplied and discharged from an air supply / discharge device (not shown) against the air supply / discharge ports a, a provided on the axis P of each end case 5, 5. The fluid discharge section disposed on the upper side of the pair of air cylinders 3 and 3 is configured to reversely expand and contract and fluid such as a chemical solution sucked from the fluid suction section ri disposed on the side of the pump body 1 is provided. It can be discharged substantially continuously from ro. In other words, the pair of bellows 2 and 2 are configured to extend and contract (retract and drive) in a contradictory manner, and while the other bellows 2 performs the fluid discharging operation, the other bellows 2 performs the fluid suction operation and reciprocates. Although it is a moving structure, fluid can be discharged continuously.

  Next, the structure of each part will be described. As shown in FIG. 1, the pump body 1 is formed in a flat and substantially cylindrical shape with central portions on the left and right sides protruding outward. A thick flange 2a of a bellows 2 is fitted into a stepped recessed ring groove 1A formed on each of the left and right outer peripheral portions of the pump body 1 and is sandwiched between the pump body 1 and the intermediate case 4 It is held in a retaining shape through the end-side annular plate 9. An intake valve case 6A and a discharge valve case 7A are fitted and held in a pair of circular holes (not shown) formed on the left and right center sides of the pump body 1, and each valve case 6A, 7A includes valve bodies 6B and 7B and a coil spring 10 made of a fluororesin (PFA or the like) for pressing and urging them to the valve seats 6a and 7a.

  Valve cover 6b, 7b made of fluororesin (PFA, etc.) is screwed inside the tip of each valve case 6A, 7A provided in a state of projecting into a pump chamber (an example of a sealed space) 11 that is an internal space of the bellows 2. Equipped with wearing. The suction-side valve lid 6b is formed including a spring receiver 6c of the coil spring 10, and the discharge-side valve lid 7b is formed including a valve seat 7a. The pump body 1 has a suction passage 12 for communicating the pair of suction check valves 6 and 6 with the fluid suction portion ri, and a discharge for communicating the pair of discharge check valves 7 and 7 with the fluid suction portion ri. A path 13 is formed.

  In FIG. 1, the bellows 2 located on the left side is drawn in a state where it is at the bottom dead center that is most contracted to try to extend and move right now. Although not shown, the bellows 2 located on the right side is It is at the top dead center where it has extended the most to try to move down. Accordingly, the left discharge check valve 7 and the right suction check valve 6 are drawn in a closed state, and although not shown, the right discharge check valve 7 and the left suction check valve 6 are drawn. Is open.

  As shown in FIGS. 1 and 2, the bellows 2 includes the thick flange 2a, the bellows portion 2b, and the thick disc-shaped head portion 2c described above. An example of the operating part) 15 is integrally attached. That is, the head portion 2c is fitted into a central circular hole 15a formed in the operating plate 15, and is disposed on the pump body side with the front end side annular plate 14 facing the outer peripheral portion of the head portion 2c. By being removed, it is connected to the operating plate 15 so as to move integrally therewith. The tip side annular plate 14 is connected to the operation plate 15 by a plurality of bolts (not shown).

  The bellows 2 is made of a fluororesin, preferably PTFE (polytetrafluoroethylene), and is not formed by blow molding, but is formed by cutting a PTFE cylindrical member with a lathe using a stick tool or knife. It has been done. As shown in FIGS. 1 and 2, the bellows 2 has a mountain portion 29 and a valley portion 30 alternately provided in the bellows portion 2 b located between the thick flange 2 a and the head portion 2 c. It has a bellows shape, and a disk-shaped side surface portion 31 is provided between the peak portion 29 and the valley portion 30.

  The left and right operation plates 15, 15 are loosely fitted in the insertion holes 4 a, 4 a of the intermediate cases 4, 4, and are movably inserted into the base end side annular plate 9, and are inserted into the pump body 1. It is screwed and fixed to both ends of a connecting rod 22 that is inserted in a liquid-tight state into the seal bearing 21 to be fitted, and there are a plurality of connecting rods 22 (for example, four) at equal angles around the axis P. Is provided. A connecting rod 22 that connects the left and right actuating plates 15 and 15 is supported by the pump body 1 through a seal bearing (not shown) so as to be slidable in the direction of the axis P. This makes it possible to reliably perform general expansion and contraction. Reference numeral 16 denotes a total of four assembly bolts installed over the left and right end cases.

  In this bellows pump A, as shown in FIGS. 1 and 2, a current collecting member C made of a conductive material facing the pump chamber 11 which is a sealed space, and one end of the current collecting member C are conductively connected, and The conductive means D having the other end facing the outside of the pump body 1 is provided. That is, the current collection member C and the conductive means D constitute a static elimination means B that can discharge the static electricity (charging) in the pump chamber 11 outside the pump. A suction check valve 6 that is a suction valve and a discharge check valve 7 that is a discharge valve are supported by a stainless steel pump body 1 facing the pump chamber 11, and the suction check valve 6 and / or the discharge check valve are supported. Valve cases (examples of casings) 6A and 7A of the check valve 7 for use are screwed to the pump body 1, the current collecting member C is formed in each of the stainless steel valve cases 6A and 7A, and the pump body 1 is Each of the conductive means D is configured.

  That is, the valve cases 6A and 7A and the pump body 1 that screw-supports the valve cases 6A and 7B serve as a conduction path, and the charge charged in the pump chamber 11 is collected by the valve cases 6A and 7A and grounded from the pump body 1, etc. Can escape to the outside. Since the valve cases 6A and 7A, which are in contact with the seal target, are made of a metal material having high electrical conductivity, the valve cases 6A and 7A and the pump body before charging increases until exceeding the insulation limit of the wetted parts. 1 can be discharged, and the above-described inconvenience (inconvenience of opening a hole in the bellows due to discharge due to static charge inside the pump) can be prevented in advance. When the chemical liquid to be pumped is not corrosive, the valve cases 6A and 7A and the pump body 1 can be made of a general steel material for machine structures.

  As shown in FIG. 3, if a screwing means 23 such as a pan head screw is provided in the vicinity of the fluid discharge portion ro in the pump body 1, a grounding wire (grounding wiring) is required for discharging. It is convenient to be able to connect according to. Further, as shown in FIG. 4, if the discharge side joint 24 screwed to the fluid discharge portion ro is made of metal, for example, the pump body 1 is made using a metal pipe connected to the discharge side joint 24, that is, The pump chamber 11 can be grounded. It is also possible to adopt a structure in which the suction side joint 25 connected to the fluid suction portion ri is grounded as a metal.

[Example 2]
As shown in FIG. 5, the current collecting member C is a metal rod 26 made of stainless steel or the like that is implanted in the pump body 1 with the tip portion facing the pump chamber (sealed space) 11, and is a conductive means. D may be a static elimination means B which is a take-out rod (an example of a conducting member) 27 that is electrically connected to the rod 26 (by welding, soldering, etc.) and faces the outside of the pump body 1.

  In this case, the pump body 1 can be formed of a non-conductive material other than metal such as PTFE. The leading end 27a of the take-out rod 27 protrudes from the outer peripheral surface of the pump body 1, and is configured such that a grounding means (grounding means) such as a lead wire can be attached and detached. It is convenient if the tip 27 is formed in a male thread shape so that it can be fastened with a nut, or a female thread is formed so that a small bolt can be fastened.

Example 3
As shown in FIG. 6, the static elimination means B shown in FIG. 5 may be further developed. That is, as shown in FIG. 6, the static elimination means B of the third embodiment is provided with four bars (one example) around the axis P in the expansion and contraction direction of the bellows 2. A current collecting ring 28 that is conductively connected over the entire tip of the bar 26 is provided.

  In this case, the current collecting ring 28 is also the current collecting member C, and the current collecting members 26, 28 exist in a wide range of the pump chamber 11, and can efficiently collect charged static electricity. The current collecting ring 28 is a conductive material such as metal, and stainless steel is desirable from the viewpoint of corrosion resistance.

[Another Example]
You may employ | adopt the static elimination means B to a single cylinder type bellows pump.

DESCRIPTION OF SYMBOLS 1 Pump body 2 Bellows 6 Suction valve 6A Casing 7 Discharge valve 7A Casing 11 Sealed space 12 Suction path 13 Discharge path 15 Actuator 26 Bar material 27 Conductive member 28 Current collection ring C Current collection member Conductive means D Conductive means P Shaft center

Claims (5)

A pump body provided with a suction passage and a discharge passage for a fluid to be transferred, a bellows disposed at one end of the pump body in an airtight manner and forming a sealed space with the pump body, and the bellows An operating portion provided on the other end side of the bellows to expand and contract with respect to the pump body, a suction valve provided in the suction passage communicating with the sealed space, and provided in the discharge passage communicating with the sealed space. A bellows pump comprising a discharge valve,
A bellows pump provided with a current collecting member made of a conductive material facing the sealed space, and a conductive means having one end connected to the current collecting member and having the other end facing the outside of the pump body. .   The suction valve and the discharge valve are supported by the pump body so as to face the sealed space, a casing of the suction valve and / or the discharge valve is screwed to the pump body, and the current collecting member is a metal The bellows pump according to claim 1, wherein the bellows pump is the casing made of metal, and the conductive means is the pump body made of metal.   The bellows pump according to claim 2, wherein the casing and the pump body are made of stainless steel.   The current collecting member is a metal rod that is implanted in the pump body with a tip portion facing the sealed space, and the conductive means is electrically connected to the rod and connected to the outside of the pump body. The bellows pump according to claim 1, wherein the bellows pump is a conductive member facing the surface.   The bellows according to claim 4, wherein a plurality of the bar members are provided around an axial center of the bellows in a direction in which the bellows expands and contracts, and a current collecting ring that is conductively connected to the tip ends of the plurality of bar members is provided. pump.

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