EP0421940A1 - Gas driven pump - Google Patents

Gas driven pump Download PDF

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Publication number
EP0421940A1
EP0421940A1 EP90810760A EP90810760A EP0421940A1 EP 0421940 A1 EP0421940 A1 EP 0421940A1 EP 90810760 A EP90810760 A EP 90810760A EP 90810760 A EP90810760 A EP 90810760A EP 0421940 A1 EP0421940 A1 EP 0421940A1
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EP
European Patent Office
Prior art keywords
pump
piston
liquid
circuit
tubular body
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.)
Ceased
Application number
EP90810760A
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German (de)
French (fr)
Inventor
Frédéric Dietrich
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.)
Vacumjet AG
Original Assignee
Ecot SA
Vacumjet AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Ecot SA, Vacumjet AG filed Critical Ecot SA
Publication of EP0421940A1 publication Critical patent/EP0421940A1/en
Ceased legal-status Critical Current

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    • 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
    • F04B9/00—Piston machines or pumps characterised by the driving or driven means to or from their working members
    • F04B9/08—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid
    • F04B9/12—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being elastic, e.g. steam or air
    • F04B9/1207—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being elastic, e.g. steam or air using a source of partial vacuum or sub-atmospheric pressure
    • F04B9/1222—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being elastic, e.g. steam or air using a source of partial vacuum or sub-atmospheric pressure the return stroke being obtained by an elastic fluid under pressure

Definitions

  • pumps for pumping, transferring or moving a wide variety of liquids; generally these pumps consist of a pumping element proper, associated with an electric motor in the form of a monobloc element or in separate components.
  • a pumping element proper associated with an electric motor in the form of a monobloc element or in separate components.
  • a pneumatic control of the pump in question is therefore particularly suitable for such use; different manufacturers have proposed pneumatically actuated pumps, in particular: the utility model DE-U-8.620.319 describes a pneumatically controlled pump, the piston of which comprises three annular seals separating the working fluid from the transported fluid; in addition, the control of the intake and exhaust valves is independent of the position of the piston in the cylinder.
  • -US-A-1,816,025 describes a system comprising two pump bodies, each provided with a float, and operating alternately. Each float acts on the air intake and exhaust valves via a linkage.
  • -the patent FR-A-824,474 relates to a pump in which the position of a float controls the intake and exhaust air valves via of a set of levers.
  • the patent GB-A-1,345,627 relates to a motor supply pump, controlled by the engine gases, but the piston of which is provided with seals against the chamber.
  • the invention proposes to produce a pump which, supplied by a pneumatic control circuit, can therefore be connected directly to the pneumatic circuits of the factory, or else to its own pneumatic circuits, therefore not requiring its own motor. training.
  • the pump according to the invention comprises only one moving part, the piston, which also ensures the opening and closing of the intake and discharge circuits of the control air as well as liquid to be transferred. It is easy to choose the constituent material (s) according to the degree of corrosivity of the liquid to be circulated and, the energy source being decentralized, it is not necessary to take special precautions in the case where the pumps are placed in an explosive atmosphere.
  • the pump according to the invention has the characteristics mentioned in the claims.
  • the pump consists, as can be seen in FIG. 1, of an elongated tubular body 1, of preferably circular section but which may be of another shape, and in which a piston 2 circulates freely along the axis longitudinal of said tubular body.
  • the longitudinal axis of the tubular body 1 is vertical.
  • the tubular body is closed at its two ends by bottoms 10a and 10b fixed to the tubular body by any means suitable for the constituent materials both of tubular body 1 and bottoms 10a and 10b; the figure shows an example of a fixing system, usable in the case of a tubular body of synthetic material, where the bottom 10a, respectively 10b, is supported on a seal 11a, 11b and is tightened by bolts not shown here, between two rings 12a and 13a, respectively 12b and 13b, against a support 14a, 14b fixed to the tubular body 1.
  • the bottoms 10a and 10b can be fixed to it by welding or by any other means ensuring sealing.
  • the bottom 10a is pierced in its center with an orifice 15a opening out inside a nozzle 16a connected to the pneumatic circuit. This tip 16a is fixed to the bottom 10a by any suitable means, for example by welding.
  • a tip 16b is fixed to the bottom 10b, pierced with an orifice 15b, this tip 16b being connected to the circuit of the circulating liquid.
  • the diameters of the orifices 15a and 15b are arbitrary, but adapted to the diameter of the pipes, both of the pneumatic circuit and of the circuit of the circulating liquid to which they are connected; generally, the diameter of the orifice 15b will be larger than that of the orifice 15a.
  • the piston 2 is dimensioned so as to slide very freely inside the tubular body; in the case where it is circular, the diameter of the piston will therefore be slightly less than the inside diameter of said tubular body, so as to leave a certain clearance between the piston and the wall of the tubular body.
  • the height of the piston must be sufficient so that the latter is properly guided inside the tubular body.
  • the piston 2 is shown in Figure 1 as consisting of a cylinder in the outer side wall from which a number of grooves have been dug, as well as a recess on the bottom. These grooves and hollows play no role in the operation of the pump and simply save material.
  • the piston 2 comprises two circular grooves 20a and 20b, one on its upper face and the other on its lower face, in which are housed circular seals 21a, respectively 21b, O-ring seals for example.
  • the piston 2 defines an upper chamber 17a and a lower chamber 17b, the upper chamber extending in the direction of the bottom 10a, while the chamber 17b extends in the direction of the bottom 10b.
  • the upper chamber 17a is connected to the pneumatic control circuit
  • the orifice 15b and the endpiece 16b the lower chamber 17b is connected to the circulating liquid circuit.
  • the displacement of the piston 2 inside the tubular body 1 will therefore be controlled by the difference in pressures between the chambers 17a and 17b; in other words, when the piston has been brought against the bottom 10b by an overpressure in the chamber 17a coming from the pneumatic circuit, it completely and tightly obstructs the orifice 15b by its circular seal 21b, thus preventing the penetration of liquid inside the tubular body 1.
  • the piston 2 By reducing the air pressure in the chamber 17a, by means which we will see later, so as to make this pressure lower than that prevailing in the circuit of circulating liquid and consequently to that prevailing in the chamber 17b, the piston 2 will tend to detach from the bottom 10b and move towards the bottom 10a.
  • the material constituting the piston 2 Since the material constituting the piston 2 has a specific mass lower than that of the liquid to be circulated, said piston will float above the liquid and reach the bottom 10a before the liquid, so as to seal the orifice 15a , via the circular seal 21a, before the liquid reaches it. In this case, the chamber 17b occupies its maximum volume, this volume being filled with liquid. It will then suffice to restore sufficient pressure in the pneumatic circuit, in order to push the piston 2 towards the bottom 10b, to discharge the liquid into its circulation circuit and return to the previous initial situation.
  • the operation of the pump can be understood even better by examining FIG. 2, in which schematically the pump is represented in an application for transferring a liquid from a reservoir 30 to another reservoir 31.
  • the pneumatic control circuit 4 mainly comprises a compressor 40 and a vacuum pump 41 connected to the upper chamber 17a via a three-way valve 42, controlled by a suitable control device 42a, this device being able to be of mechanical, electrical, electronic, pneumatic or hydraulic type.
  • This control device 42a acting on the three-way valve 42 is responsible for sequentially connecting either the compressor 40, in order to impose an overpressure in the chamber 17a, said overpressure pushing the piston 2 downwards and discharging the liquid into the liquid circulation circuit 3, ie the vacuum pump 41, imposing a pressure reduction in the chamber 17a and sucking the piston 2 as well as the liquid in the chamber 17b.
  • the control device regulates the rate of rise of the piston 2 in the tubular body 1 so that the liquid remains in contact with the underside of the piston 2 and that there is no cavitation phenomenon in the chamber 17b .
  • a retention device provided with a purge 43 interposed between the pump and the three-way valve 42 makes it possible to retain any droplets or vapors of liquid, so that they are not sucked by the vacuum pump 41. So that transfer or circulation of the liquid takes place in the desired direction, two non-return valves 32 and 33 are provided on the liquid circulation circuit 3; the non-return valve 33 also makes it possible to avoid an air intake in the circuit 3.
  • Figure 3 shows a pump similar to that of Figure 1, but whose piston 2 is spherical, can be full or empty, like a ping pong ball for example, the only constraints being as before that the diameter of the sphere is slightly less than that of the tubular body 1 and that the specific mass of the sphere is less than that of the liquid.
  • the sealing devices between the orifices 15a and 15b and the piston 2 are transferred to the orifices in question, FIG. 3 representing two possible embodiments, either an O-ring 18 is placed directly on the orifice 15a, or the orifice 15b has a shape such that the spherical piston 2 comes to bear there exactly in order to close it.
  • the figure shows two possible embodiments of the sealing devices carried over the orifices, it is understood that other embodiments are possible, and that the two orifices can be equipped with the same type of device or devices different.
  • the pump has been presented here in a liquid transfer application; it is understood that it applies to many other uses, in general this type of pump can be used as suction pump, pressure pump, suction and pressure pump and circulation pump, the implementation according to one or the other of these categories being made by a judicious choice of the overpressure and the pneumatic depression controlling the movement of the piston.
  • the figure shows the pump equipped with a compressor and a vacuum pump; in the case of an application comprising a plurality of pumps, these two elements can be common to all of the pumps or even in some cases consist of the air pressure and vacuum circuits of the plant. It can even be envisaged, in the event that a vacuum is not necessary for the operation of the pump, that the vacuum pump is eliminated, the corresponding path of the three-way valve then opening onto an orifice at atmospheric pressure.
  • the constituent materials of the pump elements will be chosen according to the envisaged application, and will be able to resist in particular to the corrosive and / or temperature attack of the liquid to be transported;
  • the tubular body will preferably be made of synthetic material or, if it is necessary to have a metallic body, stainless steel may be used for example, the piston preferably being chosen from synthetic material;
  • the bottoms, end caps, seals and fixing systems will be chosen in order to resist the action of the liquid too and to be able to assemble with each other and with the tubular body.
  • the construction of a pump according to the invention is extremely simple, requiring no rotating member or very high machining precision; the only moving part being the piston, whose contact with the tubular body is very loose and is constantly “lubricated” by the liquid, the maintenance of the pump will be facilitated since it will not undergo any wear.
  • the viscosity of the liquid to be transported does not play a role in the functioning of the pump, since the speed of displacement of the piston can be regulated by the speed of establishment of the vacuum and the overpressure in the upper chamber; in the case of very viscous liquids, a device for pumping and transferring products of all viscosities, described in patent CH 647145, can come as complete the installation and help transport the said liquid.
  • the pump according to the invention of a very low unit cost, requiring no particular maintenance, adapts to all kinds of applications, in particular those requiring a large number of pumps, a real saving being due to the fact that the power source is common to all the pumps. Since this power source is decentralized and no risk of sparks can appear near the pumps, they can work in an explosive atmosphere without additional precautions.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Atmospheric Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Details Of Reciprocating Pumps (AREA)
  • Reciprocating Pumps (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)

Abstract

A pump which is extremely simple to manufacture and does not require any maintenance is formed from a tubular body (1) closed at its two ends (10a and 10b), orifices (15a and 15b) of which are connected to a pneumatic control circuit (4) and to the circulating liquid circuit (3) respectively. A piston (2) circulates freely inside the tubular body, driven by an excess pressure or a low pressure forming in the upper chamber (17a) and controlled by the pneumatic control circuit. Displacement of the piston leads to filling and emptying of the lower chamber (17b), thereby permitting pumping of a liquid. …<??>This type of pump of universal application only requires connection to a compressor (40) and to a vacuum pump (41) for driving it, it being possible for these two elements to be common to a large number of such pumps. …<IMAGE>…

Description

En de multiples occasions l'industrie a be­soin de pompes pour le pompage, le transvasement ou le déplacement de liquides les plus divers; généralement ces pompes sont constituées d'un élément de pompage proprement dit, associé à un moteur électrique sous forme d'un élément monobloc ou en composants séparés. Dans le cas de l'industrie chimique en particulier, se­lon l'appareillage utilisé, on peut être conduit à avoir besoin d'un grand nombre de pompes, nécessitant de ce fait un nombre équivalent de moteurs d'entraî­nement. Ceci conduit à un coût de l'installation élevé, de par le grand nombre de moteurs nécessaires, d'autant plus si lesdits moteurs travaillant en atmosphère ex­plosive, doivent être spécialement protégés contre l'apparition d'étincelles.On many occasions the industry needs pumps for pumping, transferring or moving a wide variety of liquids; generally these pumps consist of a pumping element proper, associated with an electric motor in the form of a monobloc element or in separate components. In the case of the chemical industry in particular, depending on the equipment used, it may be necessary to need a large number of pumps, thereby requiring an equivalent number of drive motors. This leads to a high installation cost, due to the large number of motors required, all the more if said motors working in an explosive atmosphere must be specially protected against the appearance of sparks.

Une commande pneumatique de la pompe en question est donc particulièrement propice pour un tel emploi; différents constructeurs ont proposé des pompes actionnées pneumatiquement, en particulier:
-le modèle d'utilité DE-U-8.620.319 décrit une pompe à commande pneumatique dont le piston comporte trois joints d'étanchéité annulaires séparant le fluide mo­teur, du fluide transporté; de plus, la commande des soupapes d'admission et d'évacuation se fait indépen­damment de la position du piston dans le cylindre.
-le brevet US-A-1.816.025 décrit un système comportant deux corps de pompes, chacun muni d'un flotteur, et fonctionnant en alternance. Chaque flotteur agit sur les soupapes d'admission et d'évacuation d'air par l'intermédiaire d'une tringlerie.
-le brevet FR-A-824.474 concerne une pompe dans laquel­le la position d'un flotteur commande les soupapes d'admission et d'évacuation d'air par l'intermédiaire d'un jeu de leviers.
-le brevet FR-A-1.380.748, comme le précédent, mention­ne que le flotteur n'agit que comme détecteur de niveau.
-le brevet GB-A-1.345.627 concerne une pompe d'alimen­tation d'un moteur, commandée par les gaz du moteur, mais dont le piston est muni de joints d'étanchéité contre la chambre.A pneumatic control of the pump in question is therefore particularly suitable for such use; different manufacturers have proposed pneumatically actuated pumps, in particular:
the utility model DE-U-8.620.319 describes a pneumatically controlled pump, the piston of which comprises three annular seals separating the working fluid from the transported fluid; in addition, the control of the intake and exhaust valves is independent of the position of the piston in the cylinder.
-US-A-1,816,025 describes a system comprising two pump bodies, each provided with a float, and operating alternately. Each float acts on the air intake and exhaust valves via a linkage.
-the patent FR-A-824,474 relates to a pump in which the position of a float controls the intake and exhaust air valves via of a set of levers.
-the patent FR-A-1,380,748, like the previous one, mentions that the float acts only as a level detector.
the patent GB-A-1,345,627 relates to a motor supply pump, controlled by the engine gases, but the piston of which is provided with seals against the chamber.

L'invention se propose de réaliser une pompe qui, alimentée par un circuit de commande pneumatique, peut donc être branchée directement sur les circuits pneumatiques de l'usine, ou alors sur ses propres cir­cuits pneumatiques, ne nécessitant donc pas son propre moteur d'entraînement. De plus, de par sa construction modulaire extrêmement simple, la pompe selon l'inven­tion ne comporte qu'une seule pièce en mouvement, le piston, qui assure en outre l'ouverture et la fermeture des circuits d'admission et de refoulement de l'air de commande ainsi que du liquide à transvaser. Il est fa­cile de choisir le ou les matériaux constitutifs selon le degré de corrosivité du liquide à faire circuler et, la source d'énergie étant décentralisée, il n'est pas nécessaire de prendre des précautions spéciales dans le cas où les pompes sont placées dans une atmosphère explosive. Ces avantages permettent de diminuer de fa­çon considérable le coût d'installation, voire d'ex­ploitation, d'une unité de production utilisant un grand nombre de pompes; de plus la pompe selon l'inven­tion ne comporte pas les inconvénients mentionnés des pompes de l'art antérieur.The invention proposes to produce a pump which, supplied by a pneumatic control circuit, can therefore be connected directly to the pneumatic circuits of the factory, or else to its own pneumatic circuits, therefore not requiring its own motor. training. In addition, due to its extremely simple modular construction, the pump according to the invention comprises only one moving part, the piston, which also ensures the opening and closing of the intake and discharge circuits of the control air as well as liquid to be transferred. It is easy to choose the constituent material (s) according to the degree of corrosivity of the liquid to be circulated and, the energy source being decentralized, it is not necessary to take special precautions in the case where the pumps are placed in an explosive atmosphere. These advantages make it possible to considerably reduce the cost of installing, or even operating, a production unit using a large number of pumps; moreover, the pump according to the invention does not have the mentioned drawbacks of the pumps of the prior art.

La pompe selon l'invention possède les ca­ractéristiques mentionnées dans les revendications.The pump according to the invention has the characteristics mentioned in the claims.

Le fonctionnement d'une pompe selon l'in­vention est particulièrement compréhensible en exami­nant le dessin où:

  • la figure 1 représente une vue en coupe d'u­ne forme d'exécution de la pompe selon l'invention,
  • la figure 2 est une vue schématique repré­sentant une pompe, son circuit pneumatique de commande ainsi qu'un exemple de circuit de circulation de liqui­de, et
  • la figure 3 représente une vue en coupe d'u­ne autre forme d'exécution de la pompe selon l'invention.
The operation of a pump according to the invention is particularly understandable by examining the drawing where:
  • FIG. 1 represents a sectional view of an embodiment of the pump according to the invention,
  • FIG. 2 is a schematic view showing a pump, its pneumatic control circuit and an example of a liquid circulation circuit, and
  • 3 shows a sectional view of another embodiment of the pump according to the invention.

La pompe se compose, comme on peut le voir sur la figure 1, d'un corps tubulaire allongé 1, de section préférentiellement circulaire mais pouvant être d'une autre forme, et dans lequel un piston 2 circule librement le long de l'axe longitudinal dudit corps tubulaire. L'axe longitudinal du corps tubulaire 1 est vertical. Le corps tubulaire est fermé à ses deux ex­trémités par des fonds 10a et 10b fixés au corps tubu­laire par un moyen quelconque adapté aux matériaux constitutifs tant du corps tubulaire 1 que des fonds 10a et 10b; la figure représente un exemple d'un systè­me de fixation, utilisable dans le cas d'un corps tubu­laire en matériau synthétique, où le fond 10a, respec­tivement 10b, s'appuie sur un joint d'étanchéité 11a, 11b et est serré par des boulons non représentés ici, entre deux couronnes 12a et 13a, respectivement 12b et 13b, contre un appui 14a, 14b fixé au corps tubulaire 1. Dans le cas où le corps tubulaire 1 est métallique, les fonds 10a et 10b peuvent lui être fixés par soudage ou par tout autre moyen assurant l'étanchéité. Le fond 10a est percé en son centre d'un orifice 15a débouchant à l'intérieur d'un embout 16a relié au circuit pneuma­tique. Cet embout 16a est fixé au fond 10a par n'impor­te quel moyen approprié, par soudure par exemple.The pump consists, as can be seen in FIG. 1, of an elongated tubular body 1, of preferably circular section but which may be of another shape, and in which a piston 2 circulates freely along the axis longitudinal of said tubular body. The longitudinal axis of the tubular body 1 is vertical. The tubular body is closed at its two ends by bottoms 10a and 10b fixed to the tubular body by any means suitable for the constituent materials both of tubular body 1 and bottoms 10a and 10b; the figure shows an example of a fixing system, usable in the case of a tubular body of synthetic material, where the bottom 10a, respectively 10b, is supported on a seal 11a, 11b and is tightened by bolts not shown here, between two rings 12a and 13a, respectively 12b and 13b, against a support 14a, 14b fixed to the tubular body 1. In the case where the tubular body 1 is metallic, the bottoms 10a and 10b can be fixed to it by welding or by any other means ensuring sealing. The bottom 10a is pierced in its center with an orifice 15a opening out inside a nozzle 16a connected to the pneumatic circuit. This tip 16a is fixed to the bottom 10a by any suitable means, for example by welding.

De manière analogue, un embout 16b est fixé au fond 10b, percé d'un orifice 15b, cet embout 16b étant relié au circuit du liquide en circulation. Les diamètres des orifices 15a et 15b sont quelconques, mais adaptés au diamètre des canalisations, tant du circuit pneumatique que du circuit du liquide en circu­lation auxquels ils sont reliés; généralement, le dia­mètre de l'orifice 15b sera plus grand que celui de l'orifice 15a.Similarly, a tip 16b is fixed to the bottom 10b, pierced with an orifice 15b, this tip 16b being connected to the circuit of the circulating liquid. The diameters of the orifices 15a and 15b are arbitrary, but adapted to the diameter of the pipes, both of the pneumatic circuit and of the circuit of the circulating liquid to which they are connected; generally, the diameter of the orifice 15b will be larger than that of the orifice 15a.

Le piston 2 est dimensionné afin de coulis­ser très librement à l'intérieur du corps tubulaire; dans le cas où celui-ci est de forme circulaire, le diamètre du piston sera donc légèrement inférieur au diamètre intérieur dudit corps tubulaire, de manière à laisser un certain jeu entre le piston et la paroi du corps tubulaire. La hauteur du piston devra être suffi­sante afin que ce dernier soit convenablement guidé à l'intérieur du corps tubulaire. Le piston 2 est repré­senté en figure 1 comme étant constitué d'un cylindre dans la paroi latérale extérieure duquel un certain nombre de rainures ont été creusées, de même qu'une creusure sur le fond. Ces rainures et creusure ne jouent aucun rôle quant au fonctionnement de la pompe et permettent simplement d'économiser de la matière. Le piston 2 comporte deux gorges circulaires 20a et 20b , l'une sur sa face supérieure et l'autre sur sa face in­férieure, dans lesquelles sont logés des joints circu­laires 21a, respectivement 21b, des joints O-ring par exemple.The piston 2 is dimensioned so as to slide very freely inside the tubular body; in the case where it is circular, the diameter of the piston will therefore be slightly less than the inside diameter of said tubular body, so as to leave a certain clearance between the piston and the wall of the tubular body. The height of the piston must be sufficient so that the latter is properly guided inside the tubular body. The piston 2 is shown in Figure 1 as consisting of a cylinder in the outer side wall from which a number of grooves have been dug, as well as a recess on the bottom. These grooves and hollows play no role in the operation of the pump and simply save material. The piston 2 comprises two circular grooves 20a and 20b, one on its upper face and the other on its lower face, in which are housed circular seals 21a, respectively 21b, O-ring seals for example.

A l'intérieur du corps tubulaire 1, le pis­ton 2 délimite une chambre supérieure 17a et une cham­bre inférieure 17b, la chambre supérieure s'étendant en direction du fond 10a, alors que la chambre 17b s'étend elle en direction du fond 10b. Par l'orifice 15a et l'embout 16a, la chambre supérieure 17a est reliée au circuit pneumatique de commande, alors que par l'orifi­ce 15b et l'embout 16b, la chambre inférieure 17b est reliée au circuit du liquide en circulation. Le dépla­cement du piston 2 à l'intérieur du corps tubulaire 1 sera donc commandé par la différence des pressions en­tre les chambres 17a et 17b; autrement dit, lorsque le piston a été amené contre le fond 10b par une surpres­sion dans la chambre 17a en provenance du circuit pneu­matique, il obstrue entièrement et de manière étanche l'orifice 15b de par son joint circulaire 21b, empê­chant ainsi la pénétration de liquide à l'intérieur du corps tubulaire 1. En diminuant la pression d'air dans la chambre 17a, par des moyens que nous verrons plus loin, de manière à rendre cette pression inférieure à celle régnant dans le circuit de liquide en circulation et par conséquent à celle régnant dans la chambre 17b, le piston 2 aura tendance à se décoller du fond 10b et à se mouvoir en direction du fond 10a. Vu que le maté­riau constituant le piston 2 est d'une masse spécifique inférieure à celle du liquide à faire circuler, ledit piston flottera au dessus du liquide et atteindra le fond 10a avant le liquide, de manière à obstruer de ma­nière étanche l'orifice 15a, par l'intermédiaire du joint circulaire 21a, avant que le liquide n'y parvienne. Dans ce cas, la chambre 17b occupe son volu­me maximum, ce volume étant rempli de liquide. Il suf­fira alors de rétablir une pression suffisante dans le circuit pneumatique, afin de repousser le piston 2 en direction du fond 10b, pour refouler le liquide dans son circuit de circulation et retrouver la situation initiale précédente.Inside the tubular body 1, the piston 2 defines an upper chamber 17a and a lower chamber 17b, the upper chamber extending in the direction of the bottom 10a, while the chamber 17b extends in the direction of the bottom 10b. By the orifice 15a and the endpiece 16a, the upper chamber 17a is connected to the pneumatic control circuit, while by the orifice 15b and the endpiece 16b, the lower chamber 17b is connected to the circulating liquid circuit. The displacement of the piston 2 inside the tubular body 1 will therefore be controlled by the difference in pressures between the chambers 17a and 17b; in other words, when the piston has been brought against the bottom 10b by an overpressure in the chamber 17a coming from the pneumatic circuit, it completely and tightly obstructs the orifice 15b by its circular seal 21b, thus preventing the penetration of liquid inside the tubular body 1. By reducing the air pressure in the chamber 17a, by means which we will see later, so as to make this pressure lower than that prevailing in the circuit of circulating liquid and consequently to that prevailing in the chamber 17b, the piston 2 will tend to detach from the bottom 10b and move towards the bottom 10a. Since the material constituting the piston 2 has a specific mass lower than that of the liquid to be circulated, said piston will float above the liquid and reach the bottom 10a before the liquid, so as to seal the orifice 15a , via the circular seal 21a, before the liquid reaches it. In this case, the chamber 17b occupies its maximum volume, this volume being filled with liquid. It will then suffice to restore sufficient pressure in the pneumatic circuit, in order to push the piston 2 towards the bottom 10b, to discharge the liquid into its circulation circuit and return to the previous initial situation.

Le fonctionnement de la pompe se comprend encore mieux en examinant la figure 2, où d'une manière schmématique la pompe est représentée dans une applica­tion de transvasement d'un liquide d'un réservoir 30 à un autre réservoir 31. Le circuit pneumatique de com­mande 4 comprend principalement un compresseur 40 et une pompe à vide 41 reliés à la chambre supérieure 17a par l'intermédiaire d'une vanne à trois voies 42, com­mandée par un dispositif de commande adéquat 42a, ce dispositif pouvant être de type mécanique, électrique, électronique, pneumatique ou hydraulique. Ce dispositif de commande 42a agissant sur la vanne à trois voies 42, est chargé de connecter séquentiellement soit le com­presseur 40, afin d'imposer une surpression dans la chambre 17a, ladite surpression poussant le piston 2 vers le bas et refoulant le liquide dans le circuit de circulation de liquide 3, soit la pompe à vide 41, im­posant une diminution de pression dans la chambre 17a et aspirant le piston 2 ainsi que le liquide dans la chambre 17b. Le dispositif de commande règle la vitesse de montée du piston 2 dans le corps tubulaire 1 de tel­le façon que le liquide reste en contact avec la face inférieure du piston 2 et que l'on n'ait pas de phéno­mène de cavitation dans la chambre 17b. Un dispositif de rétention muni d'une purge 43 intercalé entre la pompe et la vanne à trois voies 42 permet de retenir d'éventuelles gouttelettes ou vapeurs de liquide, afin qu'elles ne soient pas aspirées par la pompe à vide 41. Afin que le transvasement ou la circulation du liquide s'effectue dans le sens désiré, deux clapets anti-­retour 32 et 33, sont prévus sur le circuit de circula­tion du liquide 3; le clapet anti-retour 33 permet en outre d'éviter une aspiration d'air dans le circuit 3.The operation of the pump can be understood even better by examining FIG. 2, in which schematically the pump is represented in an application for transferring a liquid from a reservoir 30 to another reservoir 31. The pneumatic control circuit 4 mainly comprises a compressor 40 and a vacuum pump 41 connected to the upper chamber 17a via a three-way valve 42, controlled by a suitable control device 42a, this device being able to be of mechanical, electrical, electronic, pneumatic or hydraulic type. This control device 42a acting on the three-way valve 42, is responsible for sequentially connecting either the compressor 40, in order to impose an overpressure in the chamber 17a, said overpressure pushing the piston 2 downwards and discharging the liquid into the liquid circulation circuit 3, ie the vacuum pump 41, imposing a pressure reduction in the chamber 17a and sucking the piston 2 as well as the liquid in the chamber 17b. The control device regulates the rate of rise of the piston 2 in the tubular body 1 so that the liquid remains in contact with the underside of the piston 2 and that there is no cavitation phenomenon in the chamber 17b . A retention device provided with a purge 43 interposed between the pump and the three-way valve 42 makes it possible to retain any droplets or vapors of liquid, so that they are not sucked by the vacuum pump 41. So that transfer or circulation of the liquid takes place in the desired direction, two non-return valves 32 and 33 are provided on the liquid circulation circuit 3; the non-return valve 33 also makes it possible to avoid an air intake in the circuit 3.

La figure 3 représente une pompe semblable à celle de la figure 1, mais dont le piston 2 est de for­me sphérique, pouvant être plein ou vide, à la manière d'une balle de ping-pong par exemple, les seules con­traintes étant comme précédemment que le diamètre de la sphère soit légèrement inférieur à celui du corps tubu­laire 1 et que la masse spécifique de la sphère soit inférieure à celle du liquide. Dans cette forme d'exé­ cution, les dispositifs d'étanchéité entre les orifices 15a et 15b et le piston 2 sont reportés sur les orifi­ces en question, la figure 3 représentant deux formes d'exécution possibles, soit un joint torique 18 est disposé directement sur l'orifice 15a, soit l'orifice 15b a une forme telle que le piston sphérique 2 vient s'y appuyer exactement afin de l'obturer. La figure présente deux formes d'exécution possibles des disposi­tifs d'étanchéité reporté sur les orifices, il est bien entendu que d'autres formes d'exécution sont possibles, et que les deux orifices peuvent être équipés du même type de dispositif ou de dispositifs différents.Figure 3 shows a pump similar to that of Figure 1, but whose piston 2 is spherical, can be full or empty, like a ping pong ball for example, the only constraints being as before that the diameter of the sphere is slightly less than that of the tubular body 1 and that the specific mass of the sphere is less than that of the liquid. In this form of exe cution, the sealing devices between the orifices 15a and 15b and the piston 2 are transferred to the orifices in question, FIG. 3 representing two possible embodiments, either an O-ring 18 is placed directly on the orifice 15a, or the orifice 15b has a shape such that the spherical piston 2 comes to bear there exactly in order to close it. The figure shows two possible embodiments of the sealing devices carried over the orifices, it is understood that other embodiments are possible, and that the two orifices can be equipped with the same type of device or devices different.

La pompe a été présentée ici dans une appli­cation de transvasement d'un liquide; il est bien en­tendu qu'elle s'applique à bien d'autres utilisations, de manière générale ce type de pompe peut être employée comme pompe aspirante, pompe refoulante, pompe aspiran­te et refoulante et pompe de circulation, la mise en oeuvre selon l'une ou l'autre de ces catégories étant faite par un choix judicieux de la surpression et de la dépression pneumatique commandant le mouvement du piston. A cet effet, la figure représente la pompe équipée d'un compresseur et d'une pompe à vide; dans le cas d'une application comportant une pluralité de pom­pes, ces deux éléments peuvent être communs à l'ensem­ble des pompes ou même dans certains cas être consti­tués des circuits de pression d'air et de vide de l'usine. Il peut même être envisagé, dans le cas où une dépression ne serait pas nécessaire au fonctionnement de la pompe, que la pompe à vide soit éliminée, la voie correspondante de la vanne à trois voie débouchant alors sur un orifice à pression atmosphérique.The pump has been presented here in a liquid transfer application; it is understood that it applies to many other uses, in general this type of pump can be used as suction pump, pressure pump, suction and pressure pump and circulation pump, the implementation according to one or the other of these categories being made by a judicious choice of the overpressure and the pneumatic depression controlling the movement of the piston. For this purpose, the figure shows the pump equipped with a compressor and a vacuum pump; in the case of an application comprising a plurality of pumps, these two elements can be common to all of the pumps or even in some cases consist of the air pressure and vacuum circuits of the plant. It can even be envisaged, in the event that a vacuum is not necessary for the operation of the pump, that the vacuum pump is eliminated, the corresponding path of the three-way valve then opening onto an orifice at atmospheric pressure.

Les matériaux constitutifs des éléments de la pompe seront choisis en fonction de l'application envisagée, et seront aptes à résister en particulier à l'attaque corrosive et/ou à la température du liquide à transporter; le corps tubulaire sera préférentiellement en matière synthétique ou alors, s'il est nécessaire d'avoir un corps métallique, on pourra prendre de l'a­cier inox par exemple, le piston étant préférentielle­ment choisi en matière synthétique; les fonds, les em­bouts, les joints et les systèmes de fixation seront choisis afin de résister eux aussi à l'action du liqui­de et de pouvoir s'assembler entre eux et avec le corps tubulaire.The constituent materials of the pump elements will be chosen according to the envisaged application, and will be able to resist in particular to the corrosive and / or temperature attack of the liquid to be transported; the tubular body will preferably be made of synthetic material or, if it is necessary to have a metallic body, stainless steel may be used for example, the piston preferably being chosen from synthetic material; the bottoms, end caps, seals and fixing systems will be chosen in order to resist the action of the liquid too and to be able to assemble with each other and with the tubular body.

Comme on l'a vu, la construction d'une pompe selon l'invention est extrêmement simple, ne nécessi­tant aucun organe en rotation ni une très grande préci­sion d'usinage; la seule pièce en mouvement étant le piston, dont le contact avec le corps tubulaire est très lâche et est constamment "lubrifié" par le liqui­de, l'entretien de la pompe en sera facilité vu qu'elle ne subira aucune usure.As we have seen, the construction of a pump according to the invention is extremely simple, requiring no rotating member or very high machining precision; the only moving part being the piston, whose contact with the tubular body is very loose and is constantly "lubricated" by the liquid, the maintenance of the pump will be facilitated since it will not undergo any wear.

Les domaines d'application de ces pompes sont multiples, en particulier dans l'industrie chimi­que, celle des colorants, l'industrie alimentaire et bien d'autres. De par le fait que la chambre inférieure a un volume donné déterminé, il est possible d'utiliser une pompe de ce type comme pompe doseuse, la commande de la vanne à trois voies étant alors programmée pour commander un certain nombre de cycles de remplissage - vidage de la chambre inférieure afin de transporter un volume déterminé de liquide. La viscosité du liquide à transporter ne joue pas de rôle dans le fonctionnement de la pompe, vu que la vitesse de déplacement du piston peut être régulée par la vitesse d'établissement du vi­de et de la surpression dans la chambre supérieure; dans le cas de liquides très visqueux, un dispositif de pompage et de transfert de produits de toutes viscosi­tés, décrit dans le brevet CH 647145, peut venir com­ pléter l'installation et aider au transport dudit liquide.The fields of application of these pumps are multiple, in particular in the chemical industry, that of dyes, the food industry and many others. Due to the fact that the lower chamber has a given given volume, it is possible to use a pump of this type as a metering pump, the control of the three-way valve then being programmed to control a certain number of filling cycles - emptying of the lower chamber in order to transport a determined volume of liquid. The viscosity of the liquid to be transported does not play a role in the functioning of the pump, since the speed of displacement of the piston can be regulated by the speed of establishment of the vacuum and the overpressure in the upper chamber; in the case of very viscous liquids, a device for pumping and transferring products of all viscosities, described in patent CH 647145, can come as complete the installation and help transport the said liquid.

Ainsi, la pompe selon l'invention, d'un coût unitaire très faible, ne nécessitant aucun entretien particulier, s'adapte à toutes sortes d'applications, en particulier celles nécessitant un grand nombre de pompes, une économie réelle étant due au fait que la source de puissance est commune à l'ensemble des pompes. Vu que cette source de puissance est décentra­lisée et qu'aucun risque d'étincelle ne peut apparaître à proximité des pompes, celles-ci peuvent travailler en atmosphère explosive sans précautions supplémentaires.Thus, the pump according to the invention, of a very low unit cost, requiring no particular maintenance, adapts to all kinds of applications, in particular those requiring a large number of pumps, a real saving being due to the fact that the power source is common to all the pumps. Since this power source is decentralized and no risk of sparks can appear near the pumps, they can work in an explosive atmosphere without additional precautions.

Claims (8)

1- Pompe pour liquides, comprenant un corps formé d'un tube cylindrique (1) relié à une de ses ex­trémités à un circuit de commande pneumatique (4) et dont l'autre extrémité est reliée au circuit de liquide à pomper (3), caractérisée en ce qu'elle comprend un piston flottant (2) circulant librement à l'intérieur dudit tube, entraîné par une surpression, respective­ment une dépression en provenance dudit circuit pneuma­tique, ledit piston comprenant un joint circulaire (21a,21b) sur chacune de ses faces, destinés à obturer alternativement, soit le circuit de commande pneumati­que, soit le circuit de liquide à pomper.1- Pump for liquids, comprising a body formed by a cylindrical tube (1) connected at one of its ends to a pneumatic control circuit (4) and the other end of which is connected to the circuit of liquid to be pumped (3) , characterized in that it comprises a floating piston (2) circulating freely inside said tube, driven by an overpressure, respectively a vacuum coming from said pneumatic circuit, said piston comprising a circular seal (21a, 21b) on each of its faces, intended to block alternately, either the pneumatic control circuit, or the liquid circuit to be pumped. 2- Pompe pour liquides selon la revendica­tion 1, caractérisée en ce que la masse spécifique du matériau constituant le piston est inférieure à celle du liquide pompé.2- pump for liquids according to claim 1, characterized in that the specific mass of the material constituting the piston is less than that of the pumped liquid. 3- Pompe pour liquides selon la revendica­tion 1, caractérisée en ce qu'un jeu subsiste entre le piston et la paroi interne du corps de pompe cylindri­que et qu'aucun joint n'est disposé en cet endroit.3- pump for liquids according to claim 1, characterized in that a clearance remains between the piston and the internal wall of the cylindrical pump body and that no seal is disposed at this location. 4- Pompe pour liquides selon la revendica­tion 2, caractérisée en ce que le piston est de forme sphérique, ne comportant alors aucun joint.4- Pump for liquids according to claim 2, characterized in that the piston is spherical, then having no seal. 5- Pompe pour liquides selon la revendica­tion 1, caractérisée en ce qu'une commande séquentielle (42a) actionne le circuit pneumatique.5- pump for liquids according to claim 1, characterized in that a sequential control (42a) actuates the pneumatic circuit. 6- Utilisation d'une pompe selon l'une des revendications précédentes pour le dosage d'un liquide.6- Use of a pump according to one of the preceding claims for metering a liquid. 7- Utilisation d'une pompe selon l'une des revendications précédentes dans une atmosphère explosive.7- Use of a pump according to one of the preceding claims in an explosive atmosphere. 8- Utilisation d'une pluralité de pompes se­lon l'une des revendications précédentes, caractérisée en ce que le nombre de dispositifs de surpression, res­pectivement de dépression, est inférieur au nombre de pompes.8- Use of a plurality of pumps according to one of the preceding claims, characterized in that the number of overpressure devices, respectively depression, is less than the number of pumps.
EP90810760A 1989-10-06 1990-10-04 Gas driven pump Ceased EP0421940A1 (en)

Applications Claiming Priority (2)

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CH366189 1989-10-06
CH3661/89 1989-10-06

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EP90810760A Ceased EP0421940A1 (en) 1989-10-06 1990-10-04 Gas driven pump

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EP (1) EP0421940A1 (en)
JP (1) JPH03149359A (en)

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US5092743A (en) 1992-03-03
JPH03149359A (en) 1991-06-25

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