EP0486556B1 - Pompe a piston sans impulsions - Google Patents

Pompe a piston sans impulsions Download PDF

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Publication number
EP0486556B1
EP0486556B1 EP90912068A EP90912068A EP0486556B1 EP 0486556 B1 EP0486556 B1 EP 0486556B1 EP 90912068 A EP90912068 A EP 90912068A EP 90912068 A EP90912068 A EP 90912068A EP 0486556 B1 EP0486556 B1 EP 0486556B1
Authority
EP
European Patent Office
Prior art keywords
piston
pump
pressure seal
high pressure
passage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP90912068A
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German (de)
English (en)
Other versions
EP0486556A1 (fr
EP0486556A4 (en
Inventor
Kenneth E. Lehrke
Bruce A. Mcfadden
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Graco Inc
Original Assignee
Graco Inc
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Filing date
Publication date
Application filed by Graco Inc filed Critical Graco Inc
Publication of EP0486556A1 publication Critical patent/EP0486556A1/fr
Publication of EP0486556A4 publication Critical patent/EP0486556A4/en
Application granted granted Critical
Publication of EP0486556B1 publication Critical patent/EP0486556B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
    • F04B11/005—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using two or more pumping pistons
    • F04B11/0058—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using two or more pumping pistons with piston speed control
    • F04B11/0066—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using two or more pumping pistons with piston speed control with special shape of the actuating element
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/02—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having two cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B23/00—Pumping installations or systems
    • F04B23/04—Combinations of two or more pumps
    • F04B23/06—Combinations of two or more pumps the pumps being all of reciprocating positive-displacement type

Definitions

  • a myriad of different types of pumps are known for use in pumping various materials.
  • the number of choices of pumps suitable for such applications drops substantially, particularly when it is desired to pump such materials at relatively elevated pressures and/or at predetermined flow rates.
  • reciprocating piston pumps have been widely used in such applications, such pumps suffer from having pulses in the pressure output of the pumps during piston reversal.
  • Such pumps also suffer to a certain extent from leakage and seepage of pumped material past the seals which is particularly critical when the material is air-sensitive such as isocyanates. This leakage is in both directions and can cause environmental contamination, pumped fluid contamination and regenerative abrasive wear damage to the pump.
  • the reduction and/or elimination of pulses in the output is particularly important for circulating systems, fine spray applications and proportional metering to produce constant output.
  • Centrifugal pumps are capable of pumping abrasive materials without pressure pulses but suffer from the problems of not being positive displacement type (flow rate is not directly related to speed), inefficiency, shaft seal leakage and impose a high degree of shear on materials which may be shear-sensitive.
  • Gear pumps are commonly used for metering and proportioning apparatus due their ease in synchronising with other pumps. Such products, however, are ill-suited for pumping of abrasive materials which cause unacceptable wear.
  • US-A-4,453,898 discloses a dual-piston reciprocating pump having a rotating cam driving pistons spring-urged against it and reciprocable within a chamber having inlet and outlet check valves, and being sealed thereinto.
  • the profile of the cam is chosen so as to synchronise the pistons for pumping and filling to minimise pressure pulsations and produce a substantially constant flow of fluid.
  • the cam profile which is engaged by rollers attached to the pistons on opposite faces, provides a parabolic rise, during rotation, from 0° to 30° to create an hydraulic pulse and a dwell from 345° to 360° to ensure complete cylinder refill. It has been found that this does not give pulseless output, which it is the object of the present invention to provide.
  • US-A-3,680,985 discloses a pump having a single piston which is reciprocated into and out of a cylinder to force fluid from the cylinder into a conduit.
  • the piston is in a chamber to which inlet and outlet check valves have access and is sealingly connected to the reciprocating means by a diaphragm.
  • US-A-2,711,137 discloses a chemical feed pump with a piston reciprocated by a piston rod, the piston and rod carried by a diaphragm sealing the pumping chamber from the environment.
  • DE-A-3113737 discloses a multi-piston pump with a rotating cam whose profile is smoothly curved and engaged by each of the pistons through rollers.
  • DE-A-2608664 discloses a two piston pump driven by a cam whose profile is such as to give a dwell at the crossover points.
  • DE-A-437298 discloses a multi-piston pump driven by a cam whose profile is smoothly curved in Archimedean spirals and a dwell.
  • a fluid pump for providing substantially pulseless output comprising a plurality of piston-cylinder combinations , cam means for driving each piston in its cylinder in a reciprocating motion alternating between intake strokes and pumping strokes, so that at least one piston is in a pumping stroke at all times and the sum of the velocities of the pistons in the pumping strokes is substantially constant at any given speed of the cam means, a pressure seal between each piston and its cylinder for sealing material to be pumped, and inlet check valves, and a sealing diaphragm attached to a housing and to each piston intermediate the high pressure seal and the cam means to form a chamber to contain any material that might leak past the high pressure seal and as a barrier between the material to be pumped and the environment, the cam means having a blip for increasing the velocity sum slightly near the point of check valve seating to compensate for the non-linearity of pump output during seating of the check valves.
  • a multi-piston pump is driven by a cam.
  • the use of pistons in conjunction with diaphragms allows a much higher pressure output capability that a simple diaphragm pump and a more positive displacement action than diaphragm pumps.
  • the cam is powered by a DC motor or other type of conventional variable speed rotary driving mechanism (electric, hydraulic or the like). When used with these drives, the pump can be stalled against pressure just like a typical air-operated reciprocating piston pump. This mode allows adjustable constant flow.
  • a constant speed motor driving the pump would use a pressure switch to turn the motor on and off. Because the motion input to the pump is rotary, it can be easily synchronized with another pump(s) to provide a plural component material proportioning system or with a conveyor to more fully automate production.
  • the cam profile is designed so that the reciprocating pistons (which alternate between pumping and intake strokes) have a net velocity sum of their pumping strokes which is generally constant. By doing so, one essentially can eliminate pressure losses that create pulses which result from the piston reversal of a conventional piston pump.
  • two pistons are used although it can be appreciated that more pistons may be used if desired.
  • intake flow is controlled by check valves which typically take a discreet amount of time to seat. Fluid can flow backwards during this time causing small pump output pressure variations during the valve seating but such can be compensated for by shaping the cam profile to provide a nearly totally pulseless operation.
  • Each piston is sealed in its respective cylinder by a relatively conventional type seal mechanism. Attached to the piston on the low pressure intake side of the seal is a diaphragm which serves to isolate the fluid from the environment and assure a leak proof device. As used in this application, the term “diaphragm” is understood to include membranes, bellows or other such structures performing a similar function.
  • An intake passage provides flow directly over the piston between the main seal and the diaphragm to prevent the build-up and hardening of material in the intake section and on the piston. The intake flow then passes through the intake check and into the pumping chamber and then exits through an outlet passage which also has a check valve. This flow path minimises stagnant areas of non-flowing fluid where fluids may settle out and/or harden.
  • the passage is oriented to minimise air entrapment and continually replenish the fluid in the intake area.
  • the cam can either be of a push-pull type, that is, where the roller rides in a track or can be a conventional outer profile cam wherein the piston assembly roller is spring loaded against the cam to maintain it in position.
  • a pump 10 ( Figure 1) according to the present invention, comprises a main housing 12 in which runs a shaft 14 having a gear 16 mounted thereon.
  • a motor (not shown) which may be a DC brushless type motor, drives gear 16 and shaft 14 to turn cam 18 mounted on the end thereof.
  • a cam follower assembly 20 rides on cam 18 and comprises a follower housing 22 having a follower 24 mounted thereto via shaft 26.
  • follower housing 22 has guide rollers 28 mounted on the outside thereof which run in slots 30 in housing 12.
  • follower assembly 20 is spring loaded against cam 18 by means of a spring 32.
  • Follower assembly 20 is attached to a piston 34 and located in between follower 22 and piston 34 is a diaphragm 36. Those three parts are fastened together by a bolt 38 which passes consecutively therethrough.
  • An initial inlet passage 40 leads into a flushing chamber 42 located about piston 34 between diaphragm 36 and main pressure seal 44 in cylinder 46. Flushing chamber 42 runs circumferentially around piston 34 thus inlet flow therethrough serves to flush material through which might potentially harden off the surface of piston 34. Inlet flow thence passes through passage 48 in to main inlet passage 50 which has located in series therein a check valve 52 of a conventional nature.
  • Pumping chamber 54 is located in the end of cylinder 46 over piston 34 and also has connected thereto outlet passage 56 having an outlet check 58 of conventional design therein.
  • outlet passage 56 having an outlet check 58 of conventional design therein.
  • diaphragm 36 flexes upwardly to the point of nearly touching the upper surface 42a of flushing chamber 42 thereby continually assuring a fresh flow of material through the pump and the prevention of stagnant flow zones therein.
  • seal 44 may be of any conventional type which is capable of performing a proper sealing function, however, it can be appreciated that because diaphragm 36 is subjected to relatively low pressures, its service life will be dramatically increased to maintain the pump in a substantially leak-free state. It can also be seen that if seal 44 should leak, its leakage is from the high pressure side back into the inlet rather than into the environment.
  • a pump is easily adaptable to power operated valving, that is, valving which could be operated electrically and/or through a mechanical linkage not unlike an automotive engine such that the valve opening and closing time can be selected as desired.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)

Abstract

Une pompe (10) à cylindres et pistons multiples à mouvement alternatif comprend un entraînement de came (18) tel que la somme des vitesses lors des courses de pompage de tous les cylindres reste généralement constante. La construction étanche est réalisée en utilisant un diaphragme (36) fixé au piston (34) situé entre l'ensemble d'étanchéité principal et la came (18). On prévoit une réalisation pour l'admission d'écoulement permettant à la matière qui entre de s'écouler autour dudit piston (34) situé entre le diaphragme (36) et le joint principal de manière à empêcher ladite matière de s'accumuler et de se durcir sur le piston (34) et dans la zone d'étanchéité. Les passages d'admission (40) et d'échappement (56) sont disposés de sorte qu'aucun trou d'air ne puisse s'établir, toute bulle d'air qui rentre dans la pompe pouvant sortir en montant de ladite pompe sans entraves.

Claims (9)

  1. Pompe à fluide pour fournir une sortie sensiblement sans impulsions, comprenant une pluralité de combinaisons de pistons-cylindres (34, 46), des moyens de came (18, 24) pour entraîner chaque piston (34) selon un mouvement alternatif à l'intérieur de son cylindre (46) en alternant les courses d'admission et les courses de pompage, de manière qu'un piston (34) au moins soit dans une course de pompage en permanence et que la somme des vitesses des pistons dans la course de pompage soit sensiblement constante pour une vitesse donnée quelconque des moyens de came, un joint de pression (44) entre chaque piston (34) et son cylindre (46) pour que le matériau soit pompé de manière étanche, et des clapets de retenue d'entrée (52) ainsi qu'un diaphragme d'étanchéité (36) fixé sur un boîtier (12) et à chaque piston (34) en une position intermédiaire entre le joint de pression (44) et les moyens de came (18, 24) de manière à former une chambre qui contienne un matériau quelconque susceptible de fuir le long du joint de pression (44), et pour servir de barrière entre le matériau à pomper et l'environnement, les moyens de came comprenant un accessoire pour augmenter légèrement la somme des vitesses près du point de fermeture des clapets de retenue afin de compenser la non-linéarité de la sortie de la pompe pendant la fermeture des clapets de sécurité (52).
  2. Pompe selon la revendication 1, comprenant un passage d'entrée de rinçage (40) venant d'une source de matériau à pomper autour de chaque piston (34) en une position intermédiaire entre le diaphragme (36) et le joint de pression (44) afin de réduire au minimum la stagnation et d'empêcher l'accumulation ou la solidification du matériau pompé sur ledit piston.
  3. Pompe selon la revendication 2, dans lequel chaque cylindre (46), piston (34) et joint de pression (36) forment une chambre de pompage (54) et la pompe comprend un passage principal d'admission (50) reliant le passage d'entrée de rinçage et la chambre de pompage (54).
  4. Pompe selon la revendication 3, dans laquelle le passage principal d'admission (50) est équipé d'un clapet de retenue d'admission (52).
  5. Pompe selon l'une quelconque des revendications précédentes, dans laquelle chaque piston (34) reste en contact avec son joint (44) pendant le mouvement alternatif, caractérisée en ce qu'un diaphragme d'étanchéité (36) est fixé à un boîtier (12) et à chaque piston (34) en une position intermédiaire entre le joint de pression (44) et les moyens de came (18, 24), de manière former une chambre destinée à contenir tout matériau susceptible de fuir au delà du joint de pression (44) et une barrière entre le matériau à pomper et l'environnement, un passage de rinçage (40) conduisant d'une source de matériau à pomper autour de chaque piston (34) en une position intermédiaire entre le diaphragme (36) et le joint de pression (44) pour réduire au minimum la stagnation et empêcher l'accumulation ou la solidification de matériau pompé sur le piston (34) et un passage principal d'admission (50) reliant le passage de rinçage (40) et la chambre de pompage (54) définie par chaque cylindre (46), piston (34) et joint de pression (44).
  6. Pompe selon l'une des revendications 4 ou 5, dans laquelle le passage d'admission (50) est disposé pour être orienté dans une direction généralement verticale et est configuré pour empêcher l'emprisonnement de gaz dans la chambre de pompage (54) et dans le passage (50), de manière que les gaz éventuels s'élèvent à travers le passage pour sortir de la pompe.
  7. Pompe selon la revendication 6, comprenant un passage de sortie (56) partant de la chambre de pompage (54), les passages d'admission et de sortie (50, 56) étant disposés de manière à être orientés dans une direction généralement verticale et étant configurés pour empêcher d'emprisonner des gaz dans la chambre de pompage (54) et dans les passages (50, 56), de manière que les gaz éventuels s'élèvent dans les passages pour sortir de la pompe.
  8. Pompe selon l'une quelconque des revendications précédentes, dans laquelle les moyens de came (18) sont entraînés par un moteur à vitesse variable.
  9. Pompe selon l'une quelconque des revendications précédentes, comprenant des vannes commandées par énergie.
EP90912068A 1989-08-08 1990-07-05 Pompe a piston sans impulsions Expired - Lifetime EP0486556B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US39109789A 1989-08-08 1989-08-08
US391097 1989-08-08
PCT/US1990/003786 WO1991002158A1 (fr) 1989-08-08 1990-07-05 Pompe a piston sans impulsions

Publications (3)

Publication Number Publication Date
EP0486556A1 EP0486556A1 (fr) 1992-05-27
EP0486556A4 EP0486556A4 (en) 1992-07-08
EP0486556B1 true EP0486556B1 (fr) 1996-05-08

Family

ID=23545226

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90912068A Expired - Lifetime EP0486556B1 (fr) 1989-08-08 1990-07-05 Pompe a piston sans impulsions

Country Status (4)

Country Link
EP (1) EP0486556B1 (fr)
JP (1) JPH05501138A (fr)
DE (1) DE69026945T2 (fr)
WO (1) WO1991002158A1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5145339A (en) * 1989-08-08 1992-09-08 Graco Inc. Pulseless piston pump
JP3507212B2 (ja) * 1994-08-23 2004-03-15 日機装株式会社 無脈動ポンプ
FR2783021B1 (fr) * 1998-09-09 2000-10-13 Inst Francais Du Petrole Procede et systeme de pompage de fluide utilisant une pompe avec un debit constant a l'aspiration ou au refoulement
NO316653B1 (no) 2000-09-15 2004-03-22 Nat Oilwell Norway As Anordning ved stempelmaskin og fremgangsmate til bruk ved styring av stemplene
DE102008007406A1 (de) * 2008-02-04 2009-08-06 Continental Automotive Gmbh Hochdruckpumpe
DE102014220886A1 (de) * 2014-10-15 2016-04-21 Continental Automotive Gmbh Pumpe zur Förderung eines Fluids und Verfahren zum Zusammenbau derselben
ITUB20155940A1 (it) * 2015-11-26 2017-05-26 Settima Meccanica S R L Soc A Socio Unico Pompa volumetrica a pistoni assiali perfezionata

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE437298C (de) * 1924-04-20 1926-11-19 Guenther Schneggenburger Dipl Kolbenpumpe mit mehreren Kolben
US2572952A (en) * 1947-09-02 1951-10-30 Theodore R Rymal Self-lubricating piston rod
US2711137A (en) * 1951-02-20 1955-06-21 Clifford B Moller Chemical feed pump
DE2021651A1 (de) * 1970-05-02 1971-11-25 Teves Gmbh Alfred Querschnittskontur fuer den Statorhohlraum einer Radialkolbenpumpe
US3680985A (en) * 1970-12-28 1972-08-01 Mec O Matic The Pump
US3945768A (en) * 1974-11-06 1976-03-23 Graco Inc. Fluid motor drives pump having an active inlet valve
DE2608664A1 (de) * 1976-03-03 1977-09-08 Niepmann Ag Walchwil Vorrichtung zur erzeugung eines gleichfoermigen foerderstromes
US4453898A (en) * 1977-08-01 1984-06-12 The Perkin-Elmer Corporation Dual-piston reciprocating pump assembly
DE3113737C2 (de) * 1981-04-04 1984-09-06 Eckhard 4512 Wallenhorst Schulz Kolbenpumpe

Also Published As

Publication number Publication date
EP0486556A1 (fr) 1992-05-27
EP0486556A4 (en) 1992-07-08
WO1991002158A1 (fr) 1991-02-21
JPH05501138A (ja) 1993-03-04
DE69026945T2 (de) 1996-10-31
DE69026945D1 (de) 1996-06-13

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