MULTIPLE DISPLACEMENT PUMP

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and Applicant claims priority under 35 U.S.C. § § 120 and 121 of U.S. patent application Ser. No. 19/045,749 filed on Feb. 5, 2025, which claims priority under U.S.C. § 119 of German Application No. 10 2024 103 304.5 filed Feb. 6, 2024, the disclosures of each of which are hereby incorporated by reference. A certified copy of priority German Patent Application No. 10 2024 103 304.5 is contained in parent U.S. application Ser. No. 19/045,749.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multiple displacement pump having a pump housing that comprises two lids that lie on the outside and at least one intermediate piece that is accommodated between the lids, wherein at least two fluid chambers are formed between the lids and the at least one intermediate piece, which chambers are divided, using at least one displacer element, in each instance, into at least one propellant chamber and one media chamber, and wherein the displacer elements of the at least two fluid chambers are connected, by way of at least one connection element, with force fit and releasably, to at least one lifting rod, wherein the at least one lifting rod can extend the at least one connection element through a first passage of an adjacent first lid.

2. Description of the Related Art

Such a multiple displacement pump is already previously known from U.S. Pat. No. 2,918,878 A. Furthermore, reference should be made to AT 34296 B and CH 717057 A1.

Furthermore, DE 10 2021 104 548 A1 is previously known from the prior art. This document relates to a pneumatically operated dual-membrane pump, the membranes of which are coupled to one another using a connection element. The connection element passes through an intermediate piece that separates two fluid chambers from one another, in which chambers the membranes displace a fluid. In this regard, the connection element is extended out of the fluid chambers on one side and activates a control valve with a free end, which valve controls the alternating outflow and inflow of propellant in propellant chambers within the fluid chambers.

Dual-membrane pumps in general are pumps that work according to the displacement principle. They contain two membranes that run in the same direction and are situated in separate chambers. The membranes are clamped in place at their outer circumference. Each chamber possesses an inlet channel and an outlet channel. In front of and behind this channel there is a kick-back valve, in each instance. The chamber volume of the first media chamber is increased by means of an axial movement of the membranes, while the chamber volume of the second media chamber is reduced. By means of the change in volume, the medium is drawn in and subsequently displaced. Because of the stroke that runs in the same direction, one membrane is in suction stroke while the second one is in pumping stroke. Dual-membrane pumps are available in two different drive types. A distinction is made between a pneumatic drive and an electric drive.

The majority of the available dual-membrane pumps functions according to the peripheral flow principle. In contrast to central flow, this structure differs in the placement of the drive unit. In peripheral flow, the drive unit is situated in the center between the two membranes, while the fluid side is on the outside, in each instance. In the case of central flow, the drive unit is mounted on the outside and the fluid side is situated lying on the inside.

From U.S. Pat Nos. 11,655,810 B2, 11,174,854 B2, and 11,434,892 B2, dual-membrane pumps according to the peripheral flow principle are known, in each instance, in which the drive between the two membranes acts on a spindle that connects the membranes to one another as a connection element.

In general, the principles of dual-membrane pumps can be expanded to include the multiple displacement pump being discussed here. In the present case, pumps that do not necessarily have only two membranes, but rather two or more, are also referred to as a multiple displacement pump, and they do not necessarily have to have membranes, they can certainly also have other displacement means, such as pistons, for example.

While it is true that specifically the aforementioned pumps according to the peripheral flow principle are very compact, something that can be helpful in everyday use, nevertheless these aforementioned pumps are inflexible and cannot be adapted to external circumstances. In particular, the drive of the pump cannot be adapted. If, for example, there is a requirement in a certain environment to do without an electric drive, for example for reasons of explosion protection, then these pumps can no longer be used. Vice versa, this holds true for the pump according to DE 10 2021 104 548 A1, if this pump is brought into a usage environment in which no compressed air is available.

SUMMARY OF THE INVENTION

Against this background, the present invention is based on the task of creating a multiple displacement pump that is as variable as possible and also can be adapted, in this regard, to different usage environments.

This is achieved by means of a multiple displacement pump in accordance with the characteristics of the invention. Practical embodiments of such multiple displacement pumps are discussed below.

What is provided, in this respect, is a multiple displacement pump having a pump housing that comprises two lids that lie on the outside and at least one intermediate piece accommodated between the lids, wherein at least two fluid chambers are formed between the lids and the at least one intermediate piece, which chambers are divided, using at least one displacer element, in each instance, into at least one propellant chamber and one media chamber, and wherein the displacer elements of the at least two fluid chambers are connected, by way of at least one connection element, with force fit and preferably releasably, to at least one lifting rod. Such a multiple displacement pump is characterized, according to the invention, in that the at least one lifting rod extends the at least one connection element through a first passage of an adjacent first lid, wherein the lifting rod is connected to a first mechanical actuator, using releasable connection means, with force fit.

The pump unit and the drive unit are considered separately, according to the invention. In combination, a pump capable of functioning is formed. The special feature lies in that the pumping unit is designed for different drive methods. On the basis of the force-fit but releasable connection between the connection rod and the drive, the drive can be removed from the multiple displacement pump and a different drive can be attached to it. On the side, either a pneumatic or an electric drive unit can be adapted. In this regard, in particular, the connection means can be designed in such a way that both an electric drive and also a mechanically activated control valve can be connected to it. The switch should take place with few assembly steps. Slight changes in the pumping unit are not excluded. The user can decide, by means of this possibility, which drive is preferred, and can refit the pump accordingly within a short time.

In this regard, the pumping unit is structured in accordance with the central flow principle. The inlet and the outlet as well as the kickback valves are situated in the intermediate piece. The displacer elements can either run individually or they are mechanically connected to one another by way of the connection element. On one side, the pumping unit can be completely closed off by means of a second lid. On the opposite side, the lifting rod then projects outward. This rod is used for coupling the drive unit to the at least one connection element. To empty the pumping unit, the media chambers can have drain bores that are situated at the lowest point and are closed during operation.

To some advantage, it can be provided that the first mechanical actuator is releasably connected to the first lid on its outside that faces away from the first fluid chamber. As a result, it is true that the drive can be exchanged, but after the exchange it is connected to the pump housing again, so that in the case of transport, a unit is formed once again, which can be moved as a whole.

In this regard, it is useful if the first passage of the first lid, preferably after removal of the at least one lifting rod, can be closed off so as to be propellant-sealed. Such a closure ensures that in the event of elimination of the lifting rod that is passed to the outside, the propellant cannot exit from the propellant chamber. Fundamentally, it is also possible, in the case of a pneumatic drive, to eliminate the lifting rod and to connect the two displacer elements by way of the connection element, but otherwise to drive them only on the basis of the pressure on the propellant chambers. Accordingly, for this purpose pneumatic access openings for a connection to a pneumatic drive, which openings can be closed off in a propellant-sealed manner, can be assigned to the lids. Such access openings can be structured, in particular, in such a manner that they have a particularly simple, if applicable a standardized connection to a propellant source, in other words a compressed air connection, for example.

Aside from a connection of a housing of the mechanical actuator to the first lid, this can also be accomplished in that the first lid is formed in one piece with a housing of the mechanical actuator. In such a case, the lid with one drive can be released and a different lid with another drive can be attached instead. In this regard, it can also be provided, if necessary, that no passage opening is provided in the lid if the lifting rod does not have to pass through it.

With regard to the connection possibilities of a lifting rod that is passed to the outside, a first possibility consists in that the mechanical actuator is a control valve and that the latter is activated by the lifting rod as a function of the deflection position of the displacer elements. While, in this regard, the deflection of the displacer element takes place by means of the propellant, the control valve is activated by means of the lifting rod when an end position is reached, so that the counter-stroke is produced and the propellant chamber in question is filled again after having been emptied completely, or emptied again after having been filled completely.

In the case of mechanical designs, in particular designs based on electric drives, however, the opposite happens and the displacer elements are activated and thereby alternately displace the medium to be pumped out of the two fluid chambers. A propellant can nevertheless be provided, supplementally, so as to support the displacer elements. This is particularly relevant in the case of membranes. In such a case the propellant chambers are fluidically connected to one another and can thereby communicate with one another, in other words can exchange the propellant with one another during activation of the displacer elements.

A first possibility of an electric drive can consist in that the mechanical actuator comprises an electric drive that interacts with the lifting rod and has an alternating direction of rotation, preferably an electric motor, which interacts with a ball screw or a thread, which are optionally assigned to the lifting rod.

A further possibility consists in that the mechanical actuator comprises a cam accommodated on an axis of rotation connected with an electric motor directly or with the interposition of a gear mechanism, which cam is enclosed by a rotating bearing, which in turn is mounted so as to pivot on one end of the lifting rod.

Likewise, it can be provided that the mechanical actuator comprises a cam accommodated on an axis of rotation connected to an electric motor directly or with the interposition of a gear mechanism, which cam activates a tappet, preferably a spring-mounted tappet, which in turn is formed by the lifting rod. In order to limit the stroke in this regard, the tappet can move out, toward the cam, against a stop. In this case, the cam will not be in contact with the tappet continuously, and the conveying power is limited.

A further embodiment can provide that the lifting rod is connected to an armature of a pulling magnet, which armature is resiliently mounted relative to a fixed yoke and can be electromagnetically activated by means of applying current to an exciter coil assigned to the yoke. While in the case of this embodiment, half of the movement takes place mechanically, by means of a spring, and thereby a defined rest position can occur, in a further variant it can also be provided that the lifting rod is connected to an armature of a pulling magnet, which armature can be moved back and forth between two yokes that lie opposite one another, and can be electromagnetically activated by alternately applying current to exciter coils assigned to the yokes. Here a movement of the displacer elements takes place, in each instance, only on the basis of applying current to the exciter coils.

It can be provided, to particular advantage, that the connection element is formed to be tubular and the lifting rod is passed through the connection element, wherein the lifting rod has stop elements on both sides, adjacent to the end faces of the connection element, against which stops the connection element makes contact in the event of a longitudinal displacement of the lifting rod. This solution can be of interest, in particular, in the case of membrane pumps. It has been shown that these are subject to particularly great wear in the case of attachment of known connection elements, if they are exposed to tension stress. Also in the case of connecting the displacer element to a tubular connection element and passing a lifting rod through, which rod has stop elements on both sides of the connection element, the connection element and thereby also the displacer elements connected in this manner can be constantly pushed with every movement. When using membranes, particularly gentle activation of them occurs.

In such a case, it can furthermore be provided that at least one end-face stop element of the lifting rod is releasably connected to the lifting rod, preferably by means of a screw connection. This simplifies the installation of the lifting rod, which, without the end-face stop element, can be passed through the connection element and the corresponding connection openings of the at least one displacer element involved, and can then be fixed in place on the basis of the connection means, in particular by means of a screw connection. The second stop element can be attached in a different manner, for one thing, in the case of a multi-part lifting rod, inserted between two elements, or can be attached to the lifting rod with force fit or shape fit, by means of shrinking it on or welding it on.

If, in contrast, the lifting rod is left out, for example in the case of pneumatic operation, then it can be provided that the tubular connection element can be releasably closed off after removing the lifting rod, at least in one position, preferably at both ends. In particular, it must be ensured that the chambers that lie on both sides of the connection element cannot communicate with one another beyond the connection element, in other words exchange propellant with one another, or actually mix propellant with medium. This succeeds particularly well if the connection element is sealed off at both ends and either filled with material or closed off so as to be sealed.

While it is possible, to begin with, that the electric drive means act directly on the end of the lifting rod that faces away from the displacer elements, it can be provided, however, that the connection means are enabled for producing a shape-fit and/or force-fit connection between a mechanical connector of the mechanical actuator and the lifting rod, wherein these can be, in particular, screw connectors, a bayonet closure or a quick-release coupling.

It has already been pointed out that in the case of a purely electrically operated multiple displacement pump, it is possible that the propellant chambers of the fluid chambers are fluidically connected to one another. In such a case, it can supplementally be provided that a second, parallel displacer element is assigned to the fluid chambers, in each instance, with the formation of an interstice, preferably with the interposition of an insert, wherein the interstice is filled with a support fluid.

Furthermore provided according to the invention is a multiple displacement pump having a pump housing that comprises two lids that lie on the outside and at least one intermediate piece accommodated between the lids, wherein at least two fluid chambers are formed between the lids and the at least one intermediate piece, which chambers are divided, using at least one displacer element, in each instance, into at least one propellant chamber and one media chamber, and wherein the displacer elements of the at least two fluid chambers can be connected, together and/or separately, by way of at least one connection element, with force fit, and preferably releasably, to at least one lifting rod, wherein the at least one connection element can be extended using the at least one lifting rod, and the propellant chambers are connected to a pneumatic drive so as to act on it, by way of pneumatic access openings in the lids.

In this regard, this can fundamentally be the same multiple displacement pump as in the case described above, wherein only pneumatic operation without a lifting rod is provided, while in the embodiment described above, mechanical operation or pneumatic operation with a lifting rod is provided.

By means of such a multiple displacement pump, the membrane movement is implemented pneumatically. The pump contains a compressed air connector, by means of which compressed air is passed to a control valve. This control valve steers the propellant stream alternately into the propellant space behind the displacer elements, in each instance. By means of the inflowing propellant, pressure builds up there and moves the displacer element axially. This element thereby performs a pump stroke. As soon as the stroke has been carried out completely, the control valve is activated and subsequently switches on the propellant stream behind the second displacer element. This results in a stroke in the opposite direction.

Accordingly, it can also be provided, in this variant, that a first lid has a first passage to accommodate a lifting rod, wherein in this embodiment, the first passage is now closed off in a propellant-sealed manner.

Furthermore, here too the first lid can be formed in one piece with a housing of the pneumatic actuator.

In a further concrete embodiment, it can be provided that a pressure translation unit having a further fluid chamber is assigned to the first lid that is adjacent to the connection means, wherein the connection element is extended by means of a lifting rod, using the connection means, and the lifting rod connects the connection element to a further displacer element accommodated in the further fluid chamber, and wherein a first partial chamber of the pressure translation unit is fluidically connected to the first propellant chamber, and a second partial chamber of the pressure translation unit is fluidically connected to the second propellant chamber.

In the case of a pneumatically driven pump, which works according to the principle described above, the conveying pressure that can be achieved is approximately equal to the input pressure of the propellant. In order to reach a higher conveying pressure than the input pressure of the propellant, a pressure translation unit can be used. For this purpose, a pressure translation unit that comprises a further displacer element can be used. This can be alternately impacted on both sides with propellant, for example with compressed air. The propellant can get into the chambers of the pressure translation unit through connection channels. A pneumatic drive unit controls or regulates the propellant stream and can be flanged onto the side. The active surface of the propellant is increased as a result, while that of the medium to be conveyed remains the same. The connection element is firmly connected, in this regard, to the two displacer elements of the multiple displacement pump, as well as to the pressure translation unit.

In a further development of this characteristic, multiple parallel pressure translation units can be provided, the first partial chambers of which are fluidically connected to the first propellant chamber, and the second partial chambers of which are fluidically connected to the second propellant chamber. It is therefore possible to use multiple pressure translation units and to attach these on the side of the first or the second lid. The pressure translation unit can be structured, in particular, with a further membrane or with a further piston.

In this embodiment, as well, it can be provided that the connection element is tubular and has a passage, in the direction of a longitudinal expanse, to accommodate the lifting rod. Preferably the tubular connection element can have a releasable closure at least in one position, preferably at both ends.

Between the chambers of the multiple displacement pump, the intermediate piece serves to separate the fluid chambers and accommodates the connection element, if that is present. Preferably, it is furthermore provided that the intermediate piece has either a common suction line and a common pressure line or two separate suction lines and two separate pressure lines for the media chambers of the adjacent fluid chambers, in each instance, wherein the suction lines and the pressure lines are blocked off, relative to the media chambers, in each instance, using valves that lock in the same direction, preferably ball valves. Depending on the application, metering of multiple fluids can be made possible by means of separate suction and pressure lines, while common conveying can be made possible merely by means of common suction and pressure lines.

Furthermore, it can be provided that the intermediate piece has a reach-through opening, through which a connection element can be passed, which connects multiple displacer elements to one another and to the at least one lifting rod. In this regard, it can supplementally be provided that this reach-through opening can be closed off, which is particularly essential for the possibility of equipping the multiple displacement pump with separate drives for the different displacer elements. In order to prevent an exchange between the fluid chambers, it must be ensured that the reach-through opening is closed off in a media-sealed manner when no connection element that connects multiple displacer elements to one another is used.

By means of the use of two separate drives for each of the displacer elements, the fluid chambers can have flow at different speeds going through them, and thereby two different fluids can be conveyed at a different throughput. Depending on the conveying speed, mixtures can therefore be created at predetermined ratios. This is also possible by means of the use of an insert that is introduced into the propellant chamber on one side of the fluid chamber, because the possibility exists of thereby changing the chamber volume by means of an insert piece. For this purpose, an axially adjustable stop is installed. During the suction stroke, the suction volume is reduced by means of contact with the stop, and thereby the pump volume is also reduced. Specifically if the displacer elements, here preferably membranes, are firmly connected to one another by means of a connection element, thereby causing the center stroke to remain the same, different amounts can thus be conveyed into adjacent fluid chambers.

Finally, it can be provided that the intermediate piece and/or the lids and/or the housing of the at least one mechanical actuator has/have a support foot on at least one side, facing away from the intermediate piece. This is particularly helpful if the displacer elements are connected to one another by means of a connection element, and the connection element is extended outward to a drive. On the basis of the asymmetry that occurs as a result, a support foot ensures that the multiple displacement pump does not tend to tilt.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and features of the invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.

In the drawings,

FIG. 1A shows a multiple displacement pump according to the invention, having an extended lifting rod and two connected membranes, in a schematic representation;

FIG. 1B shows the multiple displacement pump according to FIG. 1A with a lifting rod passed through the connection element, in a schematic representation;

FIG. 2 shows the multiple displacement pump according to FIG. 1A with an insert for reducing the conveying output on one side, in a schematic representation;

FIG. 3A shows a multiple displacement pump having a pressure translation unit having a further membrane, in a schematic representation;

FIG. 3B shows a multiple displacement pump having a dual pressure translation unit having two further membranes, in a schematic representation;

FIG. 3C shows a multiple displacement pump having a pressure translation unit having a further piston, in a schematic representation;

FIG. 4A shows a multiple displacement pump having a mechanical actuator in the form of an electric motor having a ball screw, in a schematic representation;

FIG. 4B shows a multiple displacement pump having a mechanical actuator on both sides, in the form of an electric motor having a ball screw, in a schematic representation;

FIG. 4C shows a multiple displacement pump having a mechanical actuator in the form of an electric motor having a thread, in a schematic representation;

FIG. 5A shows a multiple displacement pump having a mechanical actuator in the form of a cam and an articulated lifting rod, in a schematic side view;

FIG. 5B shows the multiple displacement pump according to FIG. 5A in a top view;

FIG. 5C shows a multiple displacement pump having a mechanical actuator in the form of a cam, for acting on a tappet formed by the lifting rod, in a schematic representation;

FIG. 6A shows a multiple displacement pump having a mechanical actuator in the form of a pulling magnet with spring reset, in a schematic representation of a first stroke;

FIG. 6B shows the multiple displacement pump according to FIG. 6A in a schematic representation of a second stroke;

FIG. 6C shows a multiple displacement pump having two mechanical actuators in the form of pulling magnets with spring reset, in a schematic representation;

FIG. 6D shows a multiple displacement pump having two mechanical actuators in the form of pulling magnets having yokes that lie opposite one another and work in opposite directions, in a schematic representation;

FIG. 7A shows the multiple displacement pump according to FIG. 1A, having a media connection of the propellant chambers, in a schematic representation;

FIG. 7B shows the multiple displacement pump according to FIG. 7A, having unconnected displacer elements, in a schematic representation;

FIG. 8A shows the multiple displacement pump according to FIG. 1A, having inserts in the fluid chambers and a second displacer element, in each instance, with the formation of an interstice, in a schematic representation; and

FIG. 8B shows the multiple displacement pump according to FIG. 8A, having unconnected displacer elements, in a schematic representation.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1A shows a multiple displacement pump 1 that is produced from a first lid 2 and a second lid 3, as well as an intermediate piece 4 between the lids 2 and 3. The lids 2 and 3, together with the intermediate piece 4, in each instance, form a fluid chamber 5 and 8, respectively, wherein in the representation of the further figures, the fluid chamber shown on the left is referred to as the first fluid chamber 5, and the fluid chamber shown on the right is referred to as the second fluid chamber 8, in each instance.

In the first fluid chamber 5, a first displacer element 11 is arranged, and in the second fluid chamber 8, a second displacer element 12 is arranged, in such a manner that the fluid chambers 5 and 8 are divided, respectively, into a media chamber 7 and 10 and a propellant chamber 6 and 9. A medium to be conveyed is passed through the media chambers 7 and 10, wherein the lines required for this purpose are contained in the intermediate piece 4. Since this is not important, they are not shown subsequently. In the following figures, membranes are always drawn as displacer elements 11 and 12, but this should merely be understood to be representative. Other displacer elements, in particular pistons, could be used just as well within the scope of the present invention.

The multiple displacement pump 1 has a reach-through opening 38 in the intermediate piece 4, through which opening a connection element 13 is passed, which element connects the two displacer elements 11 and 12 to one another. On the basis of this mechanical connection, the displacer elements 11 and 12 necessarily move synchronously. By way of connection means 15, for example a screw connection, a bayonet closure or other similar means, a lifting rod 14 is assigned to the connection element 13, which rod is passed to the outside through the first lid 2. There the possibility exists of engaging on the lifting rod 14 with a mechanical actuator, so as to move the displacer elements 11 and 12, or vice versa, to have a flow valve activated by the lifting rod 14. The multiple displacement pump 1 is very variable and versatile on the basis of this construction, and can still be adapted, in particular, even after production, with regard to its drive and also with regard to further functional elements.

In the event that the lifting rod 14 is left out and that a first passage 16 of the first lid 2 is closed off and thereby becomes free, the multiple displacement pump can be switched over to pneumatic operation, for example. While the displacer elements 11 and 12 can remain coupled, pneumatic access openings 18, which can also be arranged in the intermediate piece 4, are opened up in the lids 2 and 3 and connected to a control valve. By means of alternating activation of the valve, the displacer elements 11 and 12 are then no longer activated mechanically from the outside, but rather are activated by means of a propellant that can alternately be pumped out of the first propellant chamber 5 into the second propellant chamber 8 and vice versa. However, separate control of the propellant chambers 5 and 8 is also possible. However, passage of the lifting rod 14 through the first lid 2 is practical in this case as well, so as to activate the control valve by way of the lifting rod 14 in the end positions.

FIG. 1B shows a variant of FIG. 1A, wherein the lifting rod 14 is formed concentrically with the connection element 13. The connection element 13 is accommodated between two stop elements 39 and 40, and is moved, here as well, in a reach-through opening 38 of the intermediate piece 4, since it is selected to be so long that it connects the two displacer elements 11 and 12 to one another. A seal takes place here, too, in such a manner that a medium conveyed in the media chambers 7 and 10 cannot alternate between the media chambers 7 and 10, through the reach-through opening 38.

The connection element 13, which is configured to be tubular in this regard, surrounds the lifting rod 14, so that the lifting rod 14 acts on the connection element 13, and, related to this, on the displacer elements 11 and 12 only with push, not with pull, in both movement directions. There is therefore no planar, friction-fit connection between lifting rod 14 and connection element 13, but rather the lifting rod 14 can slide in the connection element 13, between the stop elements 39 and 40, wherein the lifting rod 14, in the installed state, is mounted with as little play as possible with regard to the connection element 13. Specifically in the case of membranes, it is particularly advantageous if these are subject to stress only by pressure and not by pull, so as to increase their durability.

While a center stop element 40 can be permanently attached to the lifting rod 14 by means of welding, joining, shrinking and the like, an end-face stop element 39 is releasably connected to an end face of the lifting rod 14, for example by means of a screw connection, so that the lifting rod 14 can be pulled out through the tubular connection element 13, if necessary. The ends of the connection element 13, which remain open as a result, can then be closed off in a media-sealed manner if the lifting rod 14 is no longer supposed to be used. At the free end of the lifting rod 14, in other words opposite the end-face stop element 39, a connection means 43 is affixed, so as to produce a connection to a mechanical actuator, for example a drive motor or one of the drives presented below. A switch between different drives and types of drives, mechanical, electric, pneumatic or hydraulic, is possible as a result. Likewise, the tubular connection element 13 can also be attached only to one displacer element 11 or 12, so that the stop elements 39 and 40 lie directly on both sides of the displacer element 11 or 12. Such configurations will still be shown below and can be used if multiple drives are used for the individual displacer elements 11 and 12, particularly for the purpose of metering.

The lifting rod 14 and the at least one connection element 13 are presented in the following, together with possible connection means 15 or 43, as a single part, for the sake of simplification, in each instance.

FIG. 2 first shows a multiple displacement pump 1, in which a first displacer element 11 is moved by means of the lifting rod 14 and the connection element 13. In this regard, the first displacer element 11 can make use of the size of its fluid chamber, while a second displacer element 12 runs against a membrane stop 34 inserted into the fluid chamber there. As a result, a variable relationship between the conveyed amount in the two fluid chambers can be adjusted, something that is particularly advantageous for use as a metering pump.

FIGS. 3A, 3B, and 3C show different multiple displacement pumps 1, which work with a pressure translation unit. In order to be able to implement a higher conveying pressure as compared to the input pressure, a pressure translation unit 31 is added to the structure described above. This can be done using a further membrane 32 as in FIG. 3A, or also by way of a further piston 33 as in FIG. 3C, which divide a further fluid chamber 35 into a first partial chamber 36 and a second partial chamber 37. The use of multiple pressure translation units 31 added in parallel is also possible, in this regard, as shown in FIG. 3B.

The pressure translation unit 31 is an additional element in which a further displacer element 32 or 33 is accommodated. This can be alternately impacted by the propellant in the two partial chambers 36 and 37. The propellant, for example compressed air, can get into the propellant chambers of the pumping unit through connection channels 44. The pneumatic drive unit regulates the air controller and is flanged onto the side, but this is not shown in the figures. The active surface of the propellant is thereby increased, while that of the medium remains the same. In this regard, the connection element 13 is firmly connected to the two displacer elements of the multiple displacement pump 1, as well as to the pressure translation unit 31.

The straight-line movement of the displacer elements 11 and 12 can be produced, as shown in FIGS. 4A and 4B, by means of a motor and a ball screw 20. For this purpose, an electric motor 19 is used, in which the rotating rotor ring is structured as a drive nut. The counterpart to this is the ball screw 20. The latter moves translationally forward and back, depending on the direction of rotation of the rotor. The force/movement is transferred by means of a fixed connection to the connection element 13. In the variant of FIG. 4B, in this regard, a spindle drive is used per side, so as to move the displacer elements 11 and 12. In the case of such an arrangement, a connection of the displacer elements 11 and 12 is not necessary, and the lifting rods 14 are connected, by means of a connection element 13, in each instance, only to one displacer element 11 or 12. The two drive units can be controlled independently of one another, in this regard.

The function of a screw drive, as shown in FIG. 4C, is identical to that of the spindle drive according to FIGS. 4A and 4B. Instead of a ball screw 20, however, a thread 21 is used so as to convert the rotational movement into a translational movement.

A further variant is evident from FIGS. 5A and 5B. In the case of this variant, a cam 22 is situated on a drive shaft that serves as a rotating bearing 23, which shaft is connected to an electric motor. A gear mechanism can be situated between the electric motor and the drive shaft. Around this cam 22, there is a housing 45 mounted so as to rotate, having a further pivot bearing 46 for an axially guided lifting rod. The rotation of the drive shaft thereby brings about a straight-line forward or backward movement of the lifting rod 14.

A further variant according to FIG. 5c is thematically similar. In this regard, a cam 22 is firmly connected to the drive shaft of the electric motor, which shaft serves as a rotating bearing 23. Here too, a gear mechanism can be situated between the electric motor and the drive shaft. A spring-mounted tappet 24 is provided, permanently resting on the cam. By means of a rotation of the cam 22, the tappet 24 is pressed inward and the spring is compressed. As the cam 22 is rotated further, the tappet 24 moves outward again, as the result of the preload of the spring. The tappet 24 is connected to both displacer elements and transfers its movement to them.

With regard to FIGS. 6A and 6B, there a connection element is firmly connected to a movable armature 26 by way of a lifting rod 14. The armature 26 is spring-loaded on one side. A fixed exciter coil 28 is situated next to the armature 26. Together the components form a pulling magnet 25. When a voltage is applied to the exciter coil 28, a magnetic field occurs in the latter, which field attracts the armature 26 in the direction of a yoke 27, as shown in FIG. 6B. The spring 47 is tensed when this happens. When the voltage is shut off, the armature 26 is pressed into its original position according to FIG. 6A, because of the spring force.

In a further variant according to FIG. 6C, a pulling magnet 25 is used on both sides, in each instance. A displacer element 11 or 12 is connected to only one pulling magnet 25, in each instance. By means of alternately applying current to the left and right exciter coil 28, the strokes are performed. The spring 47 presses the armature 26 back into the starting position when the voltage is turned off. In this regard, the two pulling magnets 25 can be controlled independently of one another.

Furthermore, it is possible, as shown in FIG. 6D, to use two pulling magnets 25 per side. In this regard, the armature 26 is situated between them. A continuous lifting rod 14 connects the two armatures, as well as the displacer elements 11 and 12, to one another by way of connection elements 13. When the voltage is applied, the outer exciter coil on the left side has current applied to it by the inner exciter coil on the right side, simultaneously with the inner exciter coil on the left side having current applied to it by the outer exciter coil on the right side.

When using a pneumatic drive unit, a pressure occurs behind the displacer element 11, 12, which pressure acts against this element. On the opposite side, the pressure of the medium prevails. The displacer element 11 or 12 is thereby impacted with pressure from both sides and permanently supported. When using an electric drive unit, this pneumatic counter-pressure is not present. The displacer element 11 or 12, respectively, is subject to the pressure on one side during operation. By means of this unilateral pressure, the wear is increased, in particular in the case of membranes, and their useful lifetime is shortened. The wear can be counteracted by means of a hydraulic support. In this regard, a liquid is filled into the propellant chambers 6 and 9 behind the membranes, until the system has been completely filled and vented. During operation, the propellant is alternately conveyed from one propellant chamber 6 into the other propellant chamber 9, and vice versa. The pressure on both sides of the membrane is almost identical. The wear is reduced. A mechanical connection of the membranes is no longer necessary, but it can be installed. FIG. 7A shows this variant with a continuous connection element 13 having a lifting rod 14; in FIG. 7B a connection element 13 is connected to a lifting rod 14 only on the left side, but on the right side, where the connection element 13 is completely sealed off, none is present.

Finally, in a further embodiment an insert 29 and a further membrane are mounted per side. An encapsulated interstice 30 is formed. In this interstice 30 there is a fluid, in particular compressed air or a liquid. During startup of the pump, the inner membrane is supported. The membrane movement takes place by means of the propellant, which is conveyed back and forth through a connection channel 44 between the first propellant chamber 6 and the second propellant chamber 9.

Thereby what has been described above is a multiple displacement pump that can be adapted, in the most variable manner possible, and, in this regard, to different use environments.

Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

REFERENCE SYMBOL LIST

• • 1 multiple displacement pump
  • 2 first lid
  • 3 second lid
  • 4 intermediate piece
  • 5 first fluid chamber
  • 6 first propellant chamber
  • 7 first media chamber
  • 8 second fluid chamber
  • 9 second propellant chamber
  • 10 second media chamber
  • 11 first displacer element
  • 12 second displacer element
  • 13 connection element
  • 14 lifting rod
  • 15 connection means
  • 16 first passage
  • 17 second passage
  • 18 pneumatic access opening
  • 19 electric motor
  • 20 ball screw
  • 21 thread
  • 22 cam
  • 23 rotating bearing
  • 24 tappet
  • 25 pulling magnet
  • 26 armature
  • 27 yoke
  • 28 exciter coil
  • 29 insert
  • 30 interstice
  • 31 pressure translation unit
  • 32 further membrane
  • 33 further piston
  • 34 membrane stop
  • 35 further fluid chamber
  • 36 first partial chamber
  • 37 second partial chamber
  • 38 reach-through opening
  • 39 end-face stop element
  • 40 center stop element
  • 41 parallel displacer element
  • 42 passage
  • 43 connection means
  • 44 connection channel
  • 45 housing
  • 46 pivot bearing
  • 47 spring