JP5062910B2 - Bellows pump - Google Patents

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 where 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 that a hole is opened 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. A fluororesin bellows 2 disposed in a state of forming an operating portion, and an operating portion 15 provided on the other end side of the fluororesin bellows 2 to extend and contract the fluororesin bellows 2 with respect to the pump body 1. the a suction valve 6 provided in the suction passage 12 communicating with the sealed space 11, the discharge valve 7 provided in the discharge passage 13 that communicates with the enclosed space 11, met bellows pump comprising a,
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. Has been
The suction valve 6 and the discharge valve 7 are supported by the pump body 1 so as to face the sealed space 11, and the casings 6 </ b> A and 7 </ b> A of the suction valve 6 and / or the discharge valve 7 are screwed to the pump body 1. The current collecting member C is the casing 6A, 7A made of stainless steel, and the conductive means D is the pump body 1 made of metal .

The invention according to claim 2 is the bellows pump according to claim 1, wherein the pump body 1 is made of stainless steel .

According to the first aspect of the invention, the casing of the intake valve and / or the discharge valve is used as a current collecting member, and the casing is screwed to a metal pump body made of stainless steel and used as a conductive means. Thus, 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 casing as the current collecting member and the pump body as 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 has been improved by devising the structure and materials so that charging does not occur inside the pump, and the inconvenience of opening holes in the fluororesin bellows due to electrostatic discharge is prevented. A pump can be provided.

Furthermore, a casing of the current collecting member is a suction valve and / or discharge valves, that the conductive means is a pump body, is configured means to take out the static electricity by essential components, a pre-Symbol effect remodeled less inexpensively There are benefits to be gained. In this case, as in the invention according to claim 2, the port Npubodi as stainless steel, the more desirable the bellows pump if so combine high corrosion resistance and high conductivity.

Half-sectional view showing the structure of a compound barrel bellows pump ( Example) 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 elimination means by another structure ( Reference Example 1 ) Schematic of bellows pump showing other static elimination means of another structure ( Reference Example 2 )

  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)
Bellows pump A according to the embodiment, as shown in FIGS. 1 and 2 is intended a pair of bellows structure as coalesced with back to back, i.e. the Fukudo type, increasing the 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 both the left and right sides protruding outward. A thick flange 2a of a bellows 2 is fitted in 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 depicted in a state where it is at the bottom dead center that is most contracted in order 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 by cutting a PTFE cylindrical member with a lathe using a stick tool, knife, or the like. 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. Note that when chemical is pumped object is of no corrosive, it is possible to the port Npubodi 1 a general steel material made of such a mechanical structure.

  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.

[ Reference Example 1 ]
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 is a discharging 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.

[ Reference Example 2 ]
As shown in FIG. 6 is a further development of the charge removing means B shown in FIG. That is, as shown in FIG. 6, the static elimination means B of Reference Example 1 is provided with four bars (one example) around the axis P in the expansion / contraction movement 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]
The single bellows type bellows pump may employ a static elimination means B configured such that the valve cases 6A and 7A serve as the conductive means D and the pump body 1 serves as the conductive means D.

1 pump body 2 bellows 6 intake valves 6A casing 7 discharge valve 7A casing 11 closed space 12 a suction path 13 discharge passage 15 actuating portion C collector member D conducting means

Claims (2)

A pump body provided with a suction path and a discharge path for a fluid to be transferred, and a fluororesin bellows disposed in a state in which one end is airtightly fixed to the pump body and a sealed space is formed between the pump body; An operating portion provided on the other end side of the fluororesin bellows to expand and contract the fluororesin bellows with respect to the pump body, an intake valve provided in the suction path communicating with the sealed space, and the sealing A bellows pump having a discharge valve provided in the discharge path communicating with the space,
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 in a state of facing 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 stainless steel A bellows pump , characterized in that the casing is made of steel and the conductive means is the pump body made of metal . Bellows pump according to claim 1, wherein the pre-Symbol pump body is made of stainless steel.

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