EP4050213A1 - Multiple membrane pump - Google Patents

Abstract

Compressed-air operated multiple membrane pumps are already known in which the valves are controlled by a slide element. This is actuated magnetically, with no mechanical intervention in this actuation. As a result, the application of force is only possible to a small extent, and therefore may not be sufficient, in particular due to static friction of the valve seal a magnetic overcoming of a dead center that may be reached jointly by the valve piston and the diaphragm piston actuating the diaphragms of the multiple diaphragm pump is made possible.

Description

The present invention relates to a multiple membrane pump with at least two membrane chambers, which are divided by at least two membranes into a propellant chamber and a media chamber, a membrane piston mechanically coupling the membranes, being guided into a switch housing and in the switch housing with the interposition of a magnet arrangement with a valve piston interacts to control an inflow and outflow of propellant into the propellant chambers.

Such a multiple diaphragm pump is already known as a double diaphragm pump DE 41 06 180 A1 previously known. In this case, radially arranged ring magnets aligned in the same direction are positioned on the interacting end pieces of the membrane piston and the valve piston on the membrane piston and the valve piston. The diaphragm piston and the valve piston work in opposite directions, in that the valve piston is pressed by the existing magnetic field of the diaphragm piston in the opposite direction of the passing diaphragm piston. Due to the oscillating movement of the mechanically driven diaphragm piston, the poles of the radial magnets of both pistons with the same name periodically come into a parallel position. The magnetic field of the valve piston gives way to the resistance that builds up as a result of the approaching poles of the same name, as the ring magnets move the valve piston into a position relative to the diaphragm piston. The opposite poles of the ring magnets of the diaphragm piston exert maximum attraction with the respective opposite poles of the valve piston. The endeavor of the two magnetic fields, each standing in the rest position to each other is used to operate the valve and the flow of propellant, since the valve piston can only be actuated magnetically.

The arrangement of the magnets described above does not allow optimal utilization of the magnetic forces, since on the one hand the frictional resistance of the valve seals must be overcome directly by the magnetic forces, and on the other hand the magnetic fields are strongly dependent on the distance between the magnets. However, since the magnetic fields are not moved towards the center of the respective counter-magnet, but only shifted past the magnet, this maximum force is not utilized in the prior art. This would also not work in the prior art, since the magnetic force is required not only in the end position, but over the entire distance of the mutual deflection of the two pistons.

Next is on the DE 693 02 656 T2 to refer, which provides a simple, parallel guidance of the diaphragm piston and valve piston, in which the valve piston is moved directly back and forth between two stop surfaces.

Against this background, the present invention is based on the object of specifying a multi-diaphragm pump in which the magnetic forces can be used more efficiently through a different distribution on the two pistons in order to prevent the multi-diaphragm pump from stopping at a common dead center of the diaphragm piston and valve piston.

This object is achieved with a multiple diaphragm pump according to the features of independent claim 1. Useful configurations of such a multiple diaphragm pump can be found in the subsequent dependent claims.

According to the invention, it is provided that there is a multiple membrane pump with a mechanical coupling of the membranes by a membrane piston.

The membranes each divide a membrane chamber into a propellant chamber and a media chamber. The membrane piston transfers part of its movement to the valve piston within a switching housing by entrainment of the valve piston. This entrainment of the valve piston activates a valve which is arranged at the end of the valve piston and which switches back and forth between two switching positions and thereby controls the inflow and outflow of the propellant into the propellant chambers. In addition to the entrainment of the valve piston by the oscillating movement of the membrane piston, part of the distance is overcome magnetically. The common dead center of the two pistons is located on this section. Dead center is a position of the pistons from which the multiple diaphragm pump can no longer get out of its own power, so that external intervention is required. This is achieved in particular when the valve piston stops in an intermediate position in which no defined valve position has been reached, but at the same time there is no longer any pressure or momentum of the diaphragm piston to move the valve piston further mechanically. If both pistons reach dead center at the same time, the multiple diaphragm pump comes to a standstill, since all valves that control the propellant are open in this position. Several magnet arrangements, preferably aligned parallel or coaxial to one another, which according to the invention are part of the interacting head pieces of both pistons, generate a magnetic force which is able to move the pistons out of their respective dead center.

This is particularly advantageous because this arrangement minimizes the required sliding distance, which must be provided by the magnetic forces alone, and a more efficient arrangement of the magnets makes better use of the effect of the magnetic force. Here, the frictional resistance of the valve seals is overcome by the mechanics of the membrane piston and not by the magnetic field of the valve piston. The magnetic field only ensures that both pistons do not reach their dead center at the same time and the movement of the double diaphragm pump comes to a standstill.

It has proven particularly advantageous if the valve piston is guided coaxially with the diaphragm piston, or at least parallel to it. In such a configuration, the force of the membrane piston can be used directly for a mechanical actuation of the valve piston, although no rigid coupling is implemented in such a case. Rather, mechanical entrainment is provided in such an arrangement, which, however, allows play between the valve piston and the diaphragm piston. As a result, the offset of the valve piston can in particular be greater than the offset of the diaphragm piston. A time offset between the movements of the valve piston and the diaphragm piston can also be made possible in this way, as a result of which the valve remains in a defined position even during the movement of the diaphragm piston.

In a specific embodiment, one of the two pistons can form a head piece, which is accommodated in a cage formed by the other of the two pistons, the head piece and the cage forming front and rear stop surfaces in the thrust direction and in the pull direction, with a stop surface between the head piece and the cage stop surfaces game is present. Irrespective of which of these two parts is associated with which of the two pistons, it is advantageous if the interaction between the diaphragm piston and the valve piston is ensured by an intermeshing structure. The free end of the valve piston can preferably be formed as a cage, while the free end of the membrane piston interacting with the valve head piece in the push and pull direction forms a head piece which is longitudinally movable in the cage.

Furthermore, first magnet arrangements can be assigned to the cage stop surfaces and at least one second magnet arrangement can be assigned to the head piece, which is oriented in the opposite direction to the first magnet arrangements. This means that the cage and head piece collide just before the end position of the cage off. The head piece then pushes the cage both mechanically and magnetically into a stop position of the cage.

The inner walls of the cage can serve as abutment surfaces for corresponding abutment surfaces of the head piece. In a sequence of movements, the membrane piston is moved by the membranes, which are deflected due to the inflow and outflow of propellant, so that the head piece and cage move relative to one another. While the valve piston initially remains at rest and the valve thus retains its position, the head piece traverses the cage and on its opposite side again comes up against the stop surfaces there. From this moment on, the valve piston is mechanically driven by the diaphragm piston.

The cage moving in the switch housing of the multiple membrane pump can also be arranged to be displaceable between two housing stop surfaces. This allows the cage to be fixed between two extreme points of movement and to ensure that the cage is always in a defined position within the switch housing.

Furthermore, third magnet arrangements aligned in the same direction as the first magnet arrangements can be provided in the housing stop surfaces, which pull the first magnet arrangements in the cage stop surfaces toward you, possibly helping to overcome the last part of the way to the housing stop surfaces. On the return movement of the head piece within the cage, this then at some point hits the opposing cage stop surfaces and from this moment takes the cage with it in the opposite direction, mechanically and magnetically. As a result, the outer cage stop surfaces are attracted to the housing stop surfaces as soon as the head piece with the pole of the same name pushes off the cage from the inside and the cage is moved towards the housing stop by the magnetic force. Thus, the cage is both by the repulsion of poles of the same name from the inside as the attraction of opposite poles from the outside also moves beyond the dead center of the valve piston.

It has proven particularly advantageous if the valve piston actuates a valve arrangement, preferably a 5/2-way valve, for controlling the flow of propellant into the propellant chambers. Specifically, the 5/2-way valve can be attached to the other end of the valve piston in order to ensure the inflow and outflow of the propellant into and out of the propellant chambers of the double diaphragm pump. With such a valve, the inflow and outflow of the propellant in both propellant chambers can be controlled simultaneously, with one propellant chamber being filled with the propellant while the propellant can escape from the other chamber at the same time.

In this case, the magnet arrangements can be constructed from one or more magnets arranged in the same direction as one another, in particular spatially distributed. The poles of all magnet arrangements that share a stop surface can be oriented either parallel or perpendicular to the direction of movement, as long as the same direction or opposite direction described above is guaranteed, which is required in order to use the applied magnetic fields to move the valve piston. For example, it is possible to attach a magnet to the head piece as long as the head piece is sufficiently thin. With a correspondingly thicker head piece, it can be useful to arrange a magnet on both sides of the head piece, which then together form the magnet arrangement. This can be transferred accordingly to the other stop surfaces. This also makes it possible to simply strengthen the magnets.

It is particularly advantageous if the magnets are permanent magnets, in particular neodymium magnets, which are preferably designed in the form of ring magnets. Choosing neodymium magnets ensures that the magnetic force is sufficient to mobilize the valve piston. In addition, a permanent magnet works without interference Interruption, which contributes to the stability of the construction and makes it maintenance-free.

In another specific embodiment, compressed air can be used as a cheap propellant. This gas is available everywhere free of charge and only needs to be compressed. It is also particularly advantageous because it does not corrode the propellant chambers and diaphragms and is both quick and easy to move.

The invention described above is explained in more detail below using an exemplary embodiment.

Figur 1

eine Mehrfachmembranpumpe in konkreter Ausgestaltung als Doppelmembranpumpe mit einem Treibmittelventil, welches über ein Schaltgehäuse mit einem Membrankolben verbunden ist in einer schematischen Darstellung einer ersten Schaltposition,

Figur 2

die Doppelmembranpumpe gemäß Figur 1 in einer zweiten Schaltposition in schematischer Darstellung,

Figur 3

die Doppelmembranpumpe gemäß Figur 1 in einer dritten Schaltposition in schematischer Darstellung,

Figur 4

die Doppelmembranpumpe gemäß Figur 1 in einer vierten Schaltposition in schematischer Darstellung, sowie

Figur 5

eine Verbindung zwischen dem Membrankolben und einem mit dem Ventil verbundenen Ventilkolben innerhalb des Schaltgehäuses in einer schematischen Darstellung.

Show it

figure 1

a multiple diaphragm pump in a specific configuration as a double diaphragm pump with a propellant valve which is connected to a diaphragm piston via a switching housing in a schematic representation of a first switching position,

figure 2

the double diaphragm pump according to figure 1 in a second switching position in a schematic representation,

figure 3

the double diaphragm pump according to figure 1 in a third switching position in a schematic representation,

figure 4

the double diaphragm pump according to figure 1 in a fourth switching position in a schematic representation, and

figure 5

a connection between the diaphragm piston and a valve piston connected to the valve within the switch housing in a schematic representation.

figure 1 shows a double diaphragm pump 1, which has two diaphragm chambers 2 and 6. The membrane chambers 2 and 6 are each divided into a propellant chamber 4 and 8 and a media chamber 3 and 7 with the aid of a membrane 5 and 9 . Compressed air is fed from a propellant source 16 via a valve arrangement 15, which is designed as a 5/2-way valve, into the second propellant chamber 8, with the aim of moving a second membrane 9 against the pressure in the second medium chamber 7 of the medium contained in the direction of the second To move media chamber 7 and thereby promote the medium from the second media chamber. The second membrane 9 is coupled to a first membrane 5 via a membrane piston 17 and entrains this in its movement, so that the first membrane 5 conveys the propellant contained there from the first propellant chamber 4 via the valve arrangement 15 out of the first propellant chamber 4. Conversely, this expands the first media chamber 3 and as a result sucks any medium that is present into it.

The valve position of the valve assembly 15 is actuated by a valve piston 10, which is in a mechanical connection with the diaphragm piston 17, as shown in FIG figure 5 is shown.

figure 2 shows the subsequent step in which the membranes 5 and 9 are deflected in the opposite direction, such play and time offset being provided between the membrane piston 17 and the valve piston 10 that the valve arrangement 15 is still in its previous position at this point in time.

figure 3 shows the next step, in which the valve arrangement 15 has now switched, so that the 5/2-way valve now has the first propellant chamber 4 with it Compressed air supplied, while the membranes 5 and 9 now begin to displace the medium from the first media chamber 3 and the compressed air from the second propellant chamber 8.

this is in figure 4 completed, but in which the valve assembly 15 has not yet switched, although the diaphragm piston 17 is approaching the end position.

figure 5 shows the interior of the switch housing 21 responsible for the switching behavior, into which the diaphragm piston 17 protrudes from the left side and the valve piston 10 protrudes from the right side. Here, the free end of the membrane piston 17 forms a head piece 19 which is received in a cage 13 at the free end of the valve piston 10 . In this case, the head piece 19 has play within the cage 13, similar to a cylinder piston in its cylinder, so that a movement of the diaphragm piston 17 only has a direct effect on the movement of the valve piston 10 if the head piece 19 with its head piece stop surfaces 20 is in contact with a cage stop surface 14 of the Cage 13 strikes and presses in the direction. Due to this purely mechanical coupling, the diaphragm piston 17 can move the valve piston 10 into a switching position in which the cage 13 of the valve piston 10 strikes the housing stop faces 22 of the housing 21 . Normally, however, this position is not reached due to the movement of the diaphragm piston 17 alone; rather, it may be that the valve piston 10 stops at a dead center shortly before the switching position, in which the valve is not in a clear switching position and the diaphragm piston 17 is due to itself the lack of pressure in the membrane chambers 2 and 6 also no longer moves. For this case, 22 magnet arrangements 11, 18 and 23 are provided in the cage 13, the head piece 19 and the housing stop surfaces, which should avoid such a dead center.

For this purpose, first magnet arrangements 11 are arranged in the same direction in the cage and third magnet arrangements 23 in the housing stop surfaces, so that they attract each other. If necessary, the third magnet arrangements can also be dispensed with, but in its end position they again magnetically pull the cage 13 towards the housing stop surfaces 22 and thereby help to overcome the undefined dead center position. A second magnet arrangement 18 aligned in opposite directions ensures that the cage 13 is pressed further in the direction of the end position at the end points, since poles of the same name point to one another and repel one another. In this way, sticking of the valve piston in the dead center can be avoided both due to the attraction of the cage 13 due to the interaction of the first magnet arrangement 11 and the third magnet arrangement 23, and due to the repulsion between the second magnet arrangement 18 of the head piece 19 and the first magnet arrangement 11 of the cage 13 towards the housing stop surface 22 can be prevented.

A multiple membrane pump is thus described above, in which the magnetic forces can be used more efficiently due to the distribution of the magnets on the two pistons, in order to avoid the standstill of the multiple membrane pump in a common dead center of membrane piston and valve piston.

REFERENCE LIST

1

double diaphragm pump

2

first membrane chamber

3

first media chamber

4

first propellant chamber

5

first membrane

6

second membrane chamber

7

second media chamber

8th

second propellant chamber

9

second membrane

10

valve piston

11

first magnet arrangement

13

Cage

14

cage stop surface

15

valve assembly

16

propellant source

17

diaphragm piston

18

second magnet arrangement

19

headpiece

20

head joint stop surface

21

switch housing

22

housing stop surface

23

third magnet arrangement

Claims (8)

Multiple membrane pump with at least two membrane chambers (2, 6), which are divided by at least two membranes (5, 9) into a propellant chamber (4, 8) and a media chamber (3, 7), a membrane piston (17) separating the membranes ( 5, 9) is mechanically coupled, is guided in a switch housing (21) and in the switch housing (21) interacts with a valve piston (10) with the interposition of a magnet arrangement for controlling the inflow and outflow of propellant into the propellant chambers (4, 8). ,
characterized in that the membrane piston (17) interacts mechanically with the valve piston (10) to actuate a valve (15) in such a way that at least one magnet arrangement (11) arranged on the valve piston (10) for moving the valve piston (10) from a rest position is moved in the plane of at least one magnet arrangement (18) arranged on the diaphragm piston (17), preferably parallel or coaxially, with the valve piston (10) being guided parallel to the diaphragm piston (17), preferably coaxial thereto, and one of the two Piston (10, 17) forms a head piece (19) which is received in one of the other of the two pistons (10, 17) formed cage (13), wherein the head piece (19) and the cage (13) in the thrust direction and form front and rear stop surfaces in the pulling direction, with play being present between the head piece stop surfaces (20) and the cage stop surfaces (14). Multiple membrane pump according to Claim 1, characterized in that the cage stop surfaces (14) are assigned first magnet arrangements (11) and the head piece is assigned at least one second magnet arrangement (18) which is aligned in opposite directions to the first magnet arrangements (11). Multiple diaphragm pump according to Claim 2, characterized in that the cage (13) is arranged to be displaceable between two housing stop faces (22). Multiple diaphragm pump according to Claim 3, characterized in that third magnet arrangements (23) aligned in the same direction as the first magnet arrangements (11) are assigned to the housing stop faces (22). Multiple membrane pump according to at least one of the preceding claims, characterized in that the valve piston (10) actuates a valve arrangement (15), preferably a 5/2-way valve, for controlling the flow of propellant into the propellant chambers (4, 8). Multiple diaphragm pump according to at least one of the preceding claims, characterized in that the magnet arrangements (11, 18, 23) are formed from one or more magnets arranged in the same direction, in particular spatially distributed. Multiple membrane pump according to at least one of the preceding claims, characterized in that the magnets are permanent magnets, in particular neodymium magnets, which are preferably designed in the form of ring magnets. Multiple diaphragm pump according to at least one of the preceding claims, characterized in that the propellant is compressed air.

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