EP2171276B1 - Diaphragm pump - Google Patents

Description

The invention relates to a diaphragm pump having at least two pump heads arranged around a central eccentric pump drive, wherein the diaphragms are drivingly connected via connecting rods to the eccentric pump drive, the eccentric pump drive having a connecting rod ring with which the connecting rod ends are provided via elastomeric intermediate elements are connected, and wherein the elastomeric intermediate element forms an elastomer joint.

Such diaphragm pumps are already known. All diaphragms of the pump heads are moved back and forth with an eccentric and a connecting rod. The membrane centers are all in the same plane, so that such pumps have a compact design. The inner connecting rod ends are pivotally connected to the eccentric drive, wherein in the region of the joint pivotal movement of the connecting rod occurs. This joint is exposed to compressive and tensile loads as well as bending loads due to the pivoting movements of the connecting rods. As a result, increased operating noise may occur due to wear and, moreover, this has a detrimental effect on the service life.

From the US 5,375,982 (Next prior art) is already a diaphragm pump of the type mentioned above with at least two pump heads previously known, which are arranged around a central eccentric pump drive around. The diaphragms provided in the pump heads are in drive connection via connecting rods with the eccentric pump drive. The eccentric pump drive has a connecting rod made of elastic material, which connects the connecting rod with the eccentric pump drive. By the elastic Connection of the connecting rod with the eccentric pump drive to reduce peak loads and a noise due to stress are counteracted.

In the DE 44 33 068 A1 already a multi-compressor pump with at least two pump heads is described above, which has a one-piece connecting rod / membrane combination. This one-piece connecting rod / membrane combination has a central region which has a recess in its main surface for receiving a bearing for a rotationally drivable eccentric. On opposite sides of this central region thrust areas are provided, wherein between the central region and a thrust region in each case a hinge region is provided, which is to generate restoring forces in a deflection of the hinge region relative to the central region. This embodiment of the one-piece connecting rod / membrane combination a good efficiency of the known diaphragm pump is aimed at simultaneously reduced number of parts. In order to keep the load of the one-piece connecting rod / membrane combination as small as possible, stops are provided to limit the design of the thrust region relative to the central region. These attacks cause an additional force for elastic deformation is necessary from a certain deflection angle, as touch the attacks and the course of the restoring forces increases disproportionately.

From the GB 1 548 888 A a diaphragm pump is previously known, engage in the two with respect to the axis of rotation of a drive diametrically opposed connecting rod to an eccentrically arranged sliding ring and slide on this during the rotational movement of the drive. The connecting rods are rigidly connected to each other by a connecting element thus axially guided by sealing rings and the membranes to their extension direction, so that the eccentrically arranged with respect to the axis of the drive slide ring causes only a radially directed with respect to the axis of the drive deflection. To reduce wear, the connecting rods are made at their points of contact with the slide ring of a metallic material.

From the EP 0 207 212 A1 is also known a diaphragm pump in which two connecting rods, which are each arranged on a membrane, are rigidly interconnected, wherein a pivot lever converts the circular motion of an eccentric drive in a linear, directed along the extension direction of the rigid connecting rod stroke movement.

From the DE 42 41 825 A1 is a low-noise high-pressure pump is known in which two radial pistons are arranged linearly displaceable in each case a piston bore and on diametrically opposite sides touching a trained as a sliding ring bearing ring, wherein in the force transmission path of a drive shaft in the piston at least one damping layer of elastomeric material is inserted. To implement the rotational movement of the drive in the linear movement of the radial piston these slide on the eccentrically arranged sliding ring.

Object of the present invention is to provide a diaphragm pump of the type mentioned, which can be produced more cost-effectively with fewer components with compact dimensions, has a low noise emission even after a long period of operation and has a high reliability.

To solve this problem, it is proposed that the connecting rod ring on the outside open-edged recesses each for at least partially receiving each connected to one intermediate element connecting rod end, and that the intermediate element forms an intermediate layer between the recess wall and the connecting rod end.

Due to the elastic connection between the connecting rod and eccentric the required joint function is given in a simple way and beyond a structure-borne sound transmission between the drive and the connecting rods is attenuated and thus prevents sound propagation on the one hand on the membranes and the pump heads, on the other hand also on the Eccentric, the shaft, the bearing and the housing.

The elastic intermediate element practically forms an elastomer joint and is permanently free of play and thus also contributes to the fact that the pump produces no disturbing noise even after a long period of operation and is maintenance-free.

Since in the diaphragm pump according to the invention the connecting rod outer edge-open recesses each for at least partially receiving the connected to an intermediate element connecting rod end, a particularly secure and durable connection between the connecting rod and the connecting rods is possible and also the exact position of the respective connection point is predetermined. The recesses on the one hand and the connecting rod ends on the other hand are dimensioned such that there is sufficient clearance between them for the elastic intermediate element and the above-described joint function. The intermediate element forms an intermediate layer between the recess wall and the connecting rod end region.

Of particular importance is the development that the spring travel of the elastic intermediate element in the axial direction of the connecting rod is smaller in comparison to the spring travel transversely to the longitudinal extent of the connecting rod.

Due to the low, elastic resilience of the intermediate element in the axial direction of the connecting rod Exzenterhub is transferred to the connecting rod in spite of the forces occurring on the connecting rod exactly. Due to the high rigidity of the intermediate element in the axial direction, the diaphragm pump is also suitable for high pumping pressures.

The spring stiffness of the intermediate element in the axial connecting rod direction is therefore large and thus the spring travel correspondingly small. For a high spring stiffness of the intermediate element in the axial connecting rod direction, the axial extent of the intermediate elements can be small.

In contrast, the spring stiffness in the radial direction of the connecting rod or intangential direction to the connecting rod is comparatively small and thus the spring travel and the elastic compliance correspondingly large.

As a result, the resulting due to the tilting movement of the connecting rod radial membrane forces are kept small and thus the otherwise otherwise highly charged by their pumping task highly loaded membrane only with low radial membrane forces.

It is particularly advantageous if elastomeric intermediate elements are connected by vulcanization on the one hand to the respective connecting rod end and on the other hand to the connecting rod ring. This gives an elastic and durable connection. In existing Pleuelring recesses, for example, the vulcanized connection with the inner wall of the recesses and the end of the connecting rod. In the simplest case, especially for small pumps, the connecting rod and the connecting rod can be directly connected with vulcanized elastomer.

In both embodiments, the connecting rod ring and the connecting rod elastically connected thereto form a structural unit.

According to a preferred embodiment of the invention, the diaphragm pump has four pump heads arranged around the central eccentric pump drive. The connecting rods of all pump heads are arranged in one plane.

Thus, the membrane centers are all in the same plane, so that the pump is compact and can be produced inexpensively with fewer components.

Additional embodiments of the invention are set forth in the further subclaims.

Fig. 1

eine Membranpumpe mit vier Pumpenköpfen und einem zentralen Exzenter-Pumpenantrieb in Querschnittsdarstellung,

Fig. 2

eine etwas schematisierte Darstellung einer vierköpfigen Membranpumpe

Fig. 3

einen Pleuelring mit außenseitig randoffenen Ausnehmungen für Zwischenelemente und Pleuelenden beziehungsweise Anschlussteile,

Fig. 4

eine vergrößerte Detailansicht im Bereich einer Ausnehmung im Pleuelring zur Aufnahme eines Zwischenelementes und eines Pleuelendes und

Fig. 5

eine schematische Darstellung einer vierköpfigen Membranpumpe mit der Verschaltung der Saugleitungen und Druckleitungen.

The invention is described in more detail below with reference to the drawings. It shows in partly schematized representation:

Fig. 1

a membrane pump with four pump heads and a central eccentric pump drive in cross-sectional view,

Fig. 2

a somewhat schematic representation of a four-headed diaphragm pump

Fig. 3

a connecting rod ring with recesses open on the outside for intermediate elements and connecting rod ends or connecting parts,

Fig. 4

an enlarged detail view in the region of a recess in the connecting rod ring for receiving an intermediate element and a connecting rod end and

Fig. 5

a schematic representation of a four-headed diaphragm pump with the interconnection of the suction and pressure lines.

An in Fig. 1 shown diaphragm pump 1 is shown in cross section and has four arranged around a central eccentric pump drive 2 around pump heads 3. The membranes 4 are in each case via connecting rods 5 with the eccentric pump drive 2 in drive connection.

The eccentric pump drive 2 has a connecting rod 6, in which a circumferential eccentric 7 is arranged. The connecting rod ring 6 may preferably be formed on the outside around or have a different outer shape. The construction of the diaphragm pump is also good in the schematic representation according to Fig. 2 recognizable.

Upon rotation of the eccentric 7 whose eccentric motion is transmitted to the connecting rod 6, so that the connecting rods 5 perform a lifting and pendulum motion. For the transmission of this drive movement of the connecting rod 6 to the connecting rod 5 joints 8 are provided, which are practically designed as elastomer joints. For this purpose, the connecting rod ends 9 are connected via elastic intermediate elements 10 with the connecting rod ring 6.

This elastic intermediate element 10 as joint 8 must meet different requirements with regard to the power transmission from the eccentric pump drive to the connecting rod 5 or the diaphragms 4. On the one hand shear and tensile forces must be transmitted, but on the other hand, a possible low-resistance lateral pivoting movement be possible. The thrust and tensile forces should be transmitted virtually directly and without play. The elastic intermediate element should therefore have a high spring stiffness in this loading direction. This can be achieved by the axial extent of the intermediate elements 10 is comparatively small. In contrast, in order to achieve a low-resistance Seitenauslenkbarkeit the connecting rod, the radial extent of the elastic intermediate element, ie transverse to the longitudinal extent the connecting rod 5, comparatively large.

In the in Fig. 2 In the embodiment shown, the radial extent of the intermediate elements 10 corresponds to the adjoining connecting rod 5. Optionally, however, the intermediate elements 10 may also have a smaller diameter or annular constrictions in order to improve the lateral mobility.

The connecting rods 5 can be vulcanized with their connecting rod ends 9 in a simple manner on the outside of the connecting rod ring 6. The vulcanized on both sides of the material forms the intermediate element 10. It is also possible to produce an elastic connection between the connecting rods and the connecting rod ring by silicone adhesive or a silicone molding.

The elastic intermediate elements 10 may therefore be formed from a vulcanized elastomer or from a castable elastomer such as silicone. Thermoplastic elastomers can also be used for the intermediate elements 10.

In Fig. 1 the connecting rod ring 6 on the outside open-edged recesses 11 each for at least partially receiving the connected to an intermediate element 10 connecting rod end 9. Here, the intermediate element 10 forms an intermediate layer between the recess wall 12 and the connecting rod end 9. Good to see here is that the different requirements with respect to the elastic compliance in the axial direction and with respect to the pivoting movement of the connecting rod 5 is achieved in that the axial distance of the connecting rod end 9 of the inner wall 12 is comparatively small and the radial distance of the connecting rod end of the inner wall is comparatively large. In the in Fig. 1 In the embodiment shown, the recesses 11 are designed to be approximately trough-shaped.

Also at the in Fig. 3 In the exemplary embodiment shown, the connecting rod ring 6 in the connecting regions of the connecting rods 5 has open-edged recesses 11a which have extensions in the outer region. Even with this design, high compressive forces can be transmitted without disturbing deflection of the connecting rod ends. On the other hand, can be done with little resistance by the Ausnehmungserweiterungen in the outdoor area, the required pivotal movement of the connecting rod ends.

Even if the recesses have a cross-sectionally approximately semicircular cross section and the projections 16, as in Fig. 3 shown, for example, have a spherical cross-section, and further these projections 16 are each completely or substantially completely within the recess, extensions are formed in the outer region, which facilitate the pivoting movement of the connecting rod ends.

In the in Fig. 3 the embodiment shown, the outer, diaphragm-side connecting rod end 9 is not directly connected to the membrane, but it is additionally provided here a Pleuelverlängerung 13, wherein the Pleuelverlängerung 13 has a threaded bolt 15 for screwing into a threaded bore 14 of the connecting rod 5.

In Fig. 1 It can be seen that the membranes 4 have a connected to the elastic membrane part, mushroom-shaped head in particular of metal, each having a threaded bolt 15a for screwing into the Pleuelgewindebohrung 14 or in an outer threaded bore of the connecting rod extension 13.

According to the embodiment Fig. 1 are the connecting rod ends 9 embedded in rubber-elastic material, which is located in the recesses 11. Here, too, forms the rubber-elastic Material, the intermediate element 10, which is vulcanized into the recesses 10 and to the connecting rod ends 9. As a rubber-elastic material, for example, silicone adhesive can be used.

The connecting rod ring 6 is preferably designed as an annular disc, wherein the radially outwardly open-edged recesses 11, 11a are formed groove-shaped. In the transverse direction, the recesses 11, 11a may extend over a portion of the annular disc thickness or over the entire thickness of the disc, so that they are open to the flat sides of the Pleuelringscheibe. The projections 16 may be cylindrical transverse bolts with a thickness corresponding to the disc thickness or shorter, so that a correspondingly large support surface is available.

If necessary, the projections 16 can also be designed as ball heads, which can be glued or vulcanized into the then preferably spherical recesses 11a. Between the ball head and the inner wall of the recess 11 a, the intermediate element 10 is formed as an elastic intermediate layer.

Furthermore, it is possible to glue or vulcanize the intermediate element 10 into the recesses 11a and to provide an insertion opening with an undercut, so that the ball heads or the like projections must be pressed in and then held in a form-fitting manner.

In the embodiment according to Fig. 3 can the recesses 11a in the connecting rod 6 about hemispherical or hemispherical disc-shaped and the projections 16 may be formed as a ball head, as a round disc or as a transversely arranged cylinder, wherein the recesses 11a and the projections 16 are dimensioned so that the molding preferably completely fits into the recess.

According to the embodiment Fig. 1 are the connecting rod ends 9 rounded, but have no cross-sectional enlargement. However, they engage comparatively deep in the elastic intermediate element 10, so that a secure holder is given.

In particular, in the embodiment according to Fig. 4 is clearly visible that the axial distance a is substantially smaller than the lateral distance, in particular the radial distance b, wherein this lateral distance to the outer end of the connecting rod still increases significantly.

The thin material layer in the axial direction gives much less on pressurization than a material layer of substantially greater thickness. Thus, the axial thrust forces are transmitted largely without deflection, while the pivoting movements of the connecting rod only a small resistance is opposed.

According to Fig. 4 have the recesses 11 in the connecting rod 6 one of a part-circular cross-sectional shape shape at the same time cylindrical or spherical or spherical disk-shaped projections 16th

The axial distance a of the connecting rod end 9 to the radial distance b of the connecting rod end in each case from the inner wall 12 of the recess may be approximately as 1: 1 to about 1: 5 behave.

Even with a layer thickness ratio of 1: 1, the pivoting movement is set against a lesser resistance than the axial thrust loading, because despite the same layer thicknesses result from the different movements and different spring travel.

In Fig. 5 is still shown schematically that the suction lines 17 on the one hand and the pressure lines 18 of the pump heads 3 on the other hand are fluidly connected to each other. With the use of several working elements (membranes 4), which are hydraulically connected in parallel, but work offset in the temporal sequence, both on the suction side and on the pressure side very low-pulsation promotion is achieved. By using a plurality of pump heads 3, for example, four pump heads and the drive torque is subject to only slight fluctuations, so that comparatively small drive motors for the eccentric pump drive 2 can be used.

Claims (13)

1. Diaphragm pump (1) with at least two pump heads (3) arranged around a central eccentric pump drive (2), the diaphragms (4) being drive-connected to the eccentric pump drive (2) via connecting rods (5), the eccentric pump drive (2) having a connecting rod ring (6), to which the connecting rod ends (9) are connected via elastomeric intermediate elements (10), and the elastomeric intermediate element forming an elastomeric joint, characterized in that the connecting rod ring (6) has on the outside open-edged marginal recesses (11, 11a) in each case for the at least partial reception of the connecting rod end (9) connected in each case to the one intermediate element (10), and in that the intermediate element (10) forms in each case an intermediate layer between the recess wall (12) and the connecting rod end (9).
2. Diaphragm pump according to Claim 1, characterized in that the spring excursion of the elastomeric intermediate element (10) in the axial direction of the connecting rods (5) is lower than the spring excursion transversely to the longitudinal extent of the connecting rods (5).
3. Diaphragm pump according to Claim 1 or 2, characterized in that the elastomeric intermediate elements (10) are connected to the respective connecting rod end (9) and to the connecting rod ring (6) by vulcanization.
4. Diaphragm pump according to one of Claims 1 to 3, characterized in that the connecting rod end (9) has a cross-sectional widening which is located at least partially inside the respective elastomeric intermediate element (10).
5. Diaphragm pump according to Claim 4, characterized in that the cross-sectional widening of the connecting rod ends (9) is formed by approximately spherical shaping or shaping in the form of a spherical disc or by a cylindrical crosspin.
6. Diaphragm pump according to one of Claims 1 to 5, characterized in that the axial distance from the connecting rod end (9) from the inner wall of the recess (11, 11a) is comparatively small and the radial distance of the connecting rod end (9) from the inner wall of the recess is comparatively large.
7. Diaphragm pump according to one of Claims 1 to 6, characterized in that the recesses (11, 11a) in the connecting rod ring (6) have a shape deviating from a shape in the form of a part-circular cross section, particularly in, the case of a shaping of the connecting rod ends (9) which is spherical or is in the form of a spherical disc.
8. Diaphragm pump according to one of Claims 1 to 7, characterized in that the recesses (11, 11a) in the connecting rod ring (6) are designed to be approximately hemispherical or in the form of a hemispherical disc or cylindrical and the shaping of the connecting rod ends (9) is designed to be approximately spherical or in the form of a spherical disc or cylindrical, and in that the recesses (11, 11a) and the shaping are dimensioned such that the shaping fits preferably completely into the recess (11, 11a).
9. Diaphragm pump according to one of Claims 1 to 8, characterized in that the axial distance (a) of the connecting rod end (9) to the radial distance (b) of the connecting rod end (9) in each case from the inner wall of the recess (11, 11a) is in the ratio of about 1:1 to about 1:5.
10. Diaphragm pump according to one of Claims 1 to 9, characterized in that the drive-side connecting rod end (9) has a connection part for connection to the intermediate element (10), and in that the connection part has a coupling point for connection to the connecting rod (5), preferably a screw-in thread.
11. Diaphragm pump according to one of Claims 1 to 10, characterized in that the suction lines (17), on the one hand, and the delivery lines (18), on the other hand, of the pump heads (3) are connected fluidically to one another.
12. Diaphragm pump according to one of Claims 1 to 11, characterized in that it has four pump heads (3) arranged around the central eccentric pump drive (2), and/or in that the connecting rods (5) of all the pump heads (3) are arranged in one plane.
13. Diaphragm pump according to one of Claims 1 to 12, characterized in that the elastomeric intermediate elements (10) are formed from a vulcanized elastomer or from a thermoplastic elastomer or from a castable elastomer, such as, for example, silicone.

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