EP1206641B1 - Membrane pump - Google Patents

Description

The invention relates to a diaphragm pump with a, a delivery chamber limiting working membrane, with one on the side facing away from the pumping chamber the Working diaphragm arranged additional membrane, with one between the working membrane and the Additional membrane provided membrane space as well as with a pump drive for one same-direction oscillating movement of the working and the additional membrane, wherein the membrane space with at least one suction channel for Pressure relief of the membrane gap connected is.

In the embodiment of the membrane Diaphragm pump one strives to have an optimum between To achieve rigidity and elasticity. While a high elasticity of the membrane required is as low as the membrane voltages it is possible to keep it possible at the same time also strive for a high rigidity, so that the Membrane under the membrane upper and underside occurring differential pressure load does not buckle and so the Creation space volume reduced or vice versa, the dead space volume increased.

The mentioned reduction of the pump chamber volume in membrane vacuum pumps especially in the lower vacuum range. In this area, large pressure differences occur Membrane top and bottom. While on the Membrane bottom usually the atmospheric pressure loads, affects the top of the membrane of the respective Evacuation pressure, with the maximum pressure difference from atmospheric pressure minus final pressure of the diaphragm pump results.

In the conventional membranes conventional diaphragm pumps, in particular if these diaphragm pumps in the range of the final pressure work and load large pressure differences on the membranes, It should be noted that the lateral elastic zone of the flexible membrane by the atmospheric pressure in Direction to the delivery room is dented. This "bulging" the membrane causes the pump chamber volume is decisively reduced, which adversely affects the Suction capacity of the diaphragm pump affects.

Particularly pronounced is this change in shape in two- and Multi-stage diaphragm pumps with low end pressures. In these Pumping is the deepest vacuum level hit hardest since here the largest pressure differences occur.

To an optimum between the desired elasticity and the had to achieve required rigidity of the membrane had In the past you always have more or less good ones Compromise solutions created, often a good Suction capacity only at the expense of high membrane tensions reached.

From DE 40 26 670 A1 is already known a diaphragm pump, the suction side via a connecting line with the Crankshaft of this diaphragm pump is connected. To the Pressure difference on both sides of the working diaphragm at least to be able to reduce or even eliminate it and Working diaphragm does not require additional differential pressure Suspend loads, the crank room is this previously known diaphragm pump with the suction side in connection.

The previously known from DE 40 26 670 A1 diaphragm pump has in practice, however, can not prevail, because the Transmission of the driving forces to those in the crankcase located crankshaft and the connection of this crankcase with the suction side of the pump an additional shaft seal presupposes. However, such a shaft seal is with further friction losses, higher wear and tear additional power requirements. A vacuum in the In addition, crank chamber can also be used to outgass the Lead the bearing oil in the connecting rod bearing, so that the ball bearing may run dry. Since the bearing grease in the crankcase over the connecting line vacuum side in the flow can reach, there is also the risk that the fluid is contaminated.

From DE 43 20 963 C2 is already known a multi-stage Pumping device with a turbo-molecular pump, the one as Hybrid pump formed dual positive displacement pump in the flow path is downstream. This hybrid pump has on the medium inlet side a reciprocating pump, which has a Downstream of the pumping medium ejecting diaphragm pump is connected. Of the Cylinder space of the reciprocating pump is opposite the crank chamber completed by a sealing membrane. It is the between the reciprocating piston on the one hand and the sealing membrane on the other hand provided gap with a suction connected, which in the flow direction in front of a suction valve the reciprocating pump opens.

Since this prior art reciprocating pump has a reciprocating piston, are in this prior art pump with a elastic membrane at pressure differential loads not occurring problems. Rather, this can be previously known reciprocating pump, the gap between the Lifting piston or its associated sealing sleeve on the one hand and the sealing membrane on the other hand, especially in the Start this prior art pumping device, soon as far Be evacuated that an undesirable overflow of Displacement of the reciprocating pump in the space deleted or but largely avoided and the entire Pumping device when starting therefore faster ready for use is.

From DE 43 28 559 C2 is already known a diaphragm pump of the type mentioned above, a working diaphragm, a Additional membrane and one between the working membrane and the Additional membrane provided membrane space has. In this membrane gap opens a suction, with whose help it is possible, the membrane gap on to bring a lower pressure before the suction channel is closed again.

Finally, FR-A 1 292 254 discloses a membrane compressor known, which has a working diaphragm and an additional diaphragm has, which delimit between them a membrane gap. The previously known membrane compressor has a pressure channel on, the membrane gap with the pressure side of Compressor connects. With the help of the pressure channel is in Membrane gap creates a pressure that the Working membrane should support and between the Atmospheric pressure and the discharge pressure is. To the in the Adjust Diaphragm Intermediate Pressure aimed at and corresponding to the pressure side of the compressor to be able to reduce, is in the pressure channel a nozzle interposed. Also only a pressure relief is at not known from FR-A 1 292 254 compressor sought.

There is therefore the particular task, one with low Effort producible diaphragm pump of the type mentioned to create, even at a high elasticity of Working diaphragm characterized by a high suction volume and at the unwanted contamination of the pumped medium avoided as far as possible.

The achievement of this task is in the Membrane pump of the type mentioned in particular in it, that the membrane gap over the at least one Suction duct with the suction side of this diaphragm pump pneumatic connected is.

In the diaphragm pump according to the invention is the membrane gap over the at least one suction channel with the Suction side of the diaphragm pump pneumatically connected. Thus, will the membrane gap evacuated continuously, such that on the top of the working diaphragm and on the bottom the working diaphragm during the suction phase always the same Pressures prevail. Because in this phase thus no Pressure difference between membrane top and bottom of the Working diaphragm works, the working diaphragm can not work Bumping direction of the pump room and an undesirable Reduction of the pump chamber volume is avoided. By the larger pumping chamber volume can increase the pumping speed in the Suction phase can be increased. This has a particularly positive effect in pressure ranges or pumping ranges, which are close to the final pressure. The pressure differences only act on the additional membrane, where they are not negative Influence on the pumping speed of the diaphragm pump can have.

Since the diaphragm pump according to the invention is the first stage of a multistage, in particular a two-stage pump or Pumping system forms, the advantage can be achieved that in the ejection phase the pressure on the membrane top of the Working diaphragm only slightly increases, because in two-stage Diaphragm pumps is the transfer pressure of the first stage well below atmospheric pressure.

As on the working membrane of the diaphragm pump according to the invention no differential pressure loads, this working diaphragm can be highly elastic be designed without the mentioned "Bulging" of this membrane is to be feared. By the more elastic design of the working diaphragm decrease the Membrane stresses clearly, which in turn a significant Increasing the membrane life brings with it. About that In addition, can be in the flexing of the working membrane Reduce shear stresses occurring, the efficiency of Improve pump and a by buckling the diaphragm conditional evacuation delay is avoided.

With the help of a more elastic working membrane can also the Membranhub the diaphragm pump according to the invention can be increased, whereby a further increase in absorbency even at can be achieved approximately the same dimensions. Up there the membrane diaphragm of the working diaphragm no Atmospheric pressure acts and the working diaphragm therefore not more noisily in the pump head at the delivery chamber strikes in the membrane pump according to the invention the Noise development significantly reduces what is especially with such diaphragm pumps, which acts as Suction pumps in medical technology should be used.

Since in the diaphragm pump according to the invention only between Working membrane and additional membrane provided membrane gap and not also the crankcase with the suction side the pump is connected, and there in the inventive Diaphragm pump the crankcase also continues, for example Under atmospheric pressure is a special Shaft seal in the crankshaft not required. In addition, because of penetration of bearing grease in the Flow rate is not expected to be undesirable Contamination of the pumped liquid avoided with certainty.

A particularly simple embodiment according to the invention provides that the membrane space on the at least a suction channel parallel to the delivery chamber with the Pump inlet is pneumatically connected. At this Embodiment sucks the pump on the one hand over the Pump inlet and on the other hand via the suction from the Membrane gap on.

A development according to the invention, in contrast, provides that the pump inlet is pneumatically connected via the membrane gap and the suction channel with the delivery chamber.
In this further embodiment according to the invention, the intake path in the pump interior runs from the pump inlet via the membrane interspace, the at least one suction channel and the inlet valve into the delivery chamber.

There is another proposal according to the invention of own worthy significance in that in the membrane space at least one Ansaugfilter- and / or noise damping element is provided. Such a diaphragm pump, in which the Ansaugfilter- and / or Noise damping element arranged in the membrane gap is, can be made very compact.

To an unwanted flutter of the membranes and a In addition to counteracting noise, it is advantageous if the Ansaugfilter- and / or Noise damping element made of an elastic material manufactured and on the one hand by the working membrane as well on the other hand is acted upon by the additional membrane.

It provides a particularly advantageous embodiment according to the invention that the Ansaugfilter- and / or noise damping element the membrane gap substantially fills.

The suction filter in the membrane gap and / or noise damping element is with a particular associated with low manufacturing overhead when considered as a open - pored and between the working membrane and the Additional membrane arranged foam element designed is.

In order to even a bulging of the elastic working diaphragm in counteract the ejection phase when the pressure on the Membrane top continuously in the direction of atmospheric pressure rises, sees a preferred embodiment according to the Invention before that the working membrane is a dimensionally stable Associated with membrane support, which is connected to a connecting rod of the Pump drive is held and the working diaphragm on the Membrane back at least in a central area conformed supports.

According to another proposal according to the invention of its own worthy of protection is provided for Working membrane and the additional membrane to a double membrane are integrally connected to each other. That's it appropriate if the working membrane and the additional membrane integral with each other via a central intermediate piece are connected and if this intermediate piece at its the Pumping chamber side facing away from an undercut Mounting hole for insertion of a shape-matched and connected to a connecting rod of the pump drive Has fastening parts.

It is particularly advantageous if the working membrane as Formed membrane is designed, the conveyor chamber side Diaphragm upper side to the contour of the pump head Delivery chamber is adapted in top dead center of the pump.

Further features of the invention will become apparent from the following Description of inventive embodiments in Connection with the claims and the drawing. The individual features can each be one by one or more an embodiment according to the invention be realized.

Fig. 1

eine Membranpumpe mit einer Arbeitsmembran, einer Zusatzmembran sowie einem zwischen diesen Membranen vorgesehenen Membran-Zwischenraum, wobei der Membran-Zwischenraum über einen Absaugkanal parallel zum Förderraum mit dem Pumpeneinlaß verbunden ist,

Fig. 2

eine Membranpumpe, ähnlich der aus Fig. 1, wobei der Förderraum über den Absaugkanal und den Membran-Zwischenraum mit dem Pumpeneinlaß pneumatisch verbunden ist,

Fig. 3

eine Membranpumpe, ähnlich der aus Fig. 1, wobei die Arbeitsmembran und die Zusatzmembran zu einer Doppelmembrane einstückig verbunden sind,

Fig. 4

die Membranpumpe aus Fig. 2, wobei ein Ansaugfilter- und Geräuschdämpfungselement aus offenporigem Schaumstoff vorgesehen ist, welches den Membran-Zwischenraum im wesentlichen ausfüllt und beidseits von den Membranen beaufschlagt wird,

Fig. 5

eine Membranpumpe, ähnlich der aus Fig. 1, wobei der Arbeitsmembrane eine formstabile Membran-Abstützung zugeordnet ist, welche die Arbeitsmembrane in der Ausstoßphase abstützt,

Fig. 6

eine zum Stand der Technik zählende Membranpumpe mit einer Flachmembrane, die unter der während der Ansaugphase einwirkenden Differenzdruckbelastung ausbeult, und

Fig. 7

eine ebenfalls zum Stand der Technik zählende Membranpumpe, deren Formmembrane wie in Fig. 6 in gleicher Weise ausbeult.

It shows:

Fig. 1

a membrane pump having a working membrane, an additional membrane and a membrane interspace provided between these membranes, the membrane interspace being connected to the pump inlet via a suction channel parallel to the delivery chamber,

Fig. 2

a membrane pump, similar to that of FIG. 1, wherein the delivery chamber is pneumatically connected to the pump inlet via the suction channel and the membrane interspace,

Fig. 3

a membrane pump, similar to that of FIG. 1, wherein the working membrane and the additional membrane are connected in one piece to form a double membrane,

Fig. 4

2, wherein a Ansaugfilter- and noise damping element made of open-cell foam is provided, which substantially fills the membrane gap and is acted upon by both sides of the membranes,

Fig. 5

a membrane pump, similar to that of FIG. 1, wherein the working membrane is associated with a dimensionally stable membrane support, which supports the working membrane in the ejection phase,

Fig. 6

a state of the art counting diaphragm pump with a flat membrane, which bulges under the applied during the suction phase differential pressure load, and

Fig. 7

a likewise counting to the prior art diaphragm pump whose form diaphragm as in Fig. 6 bulges in the same way.

In the previously known diaphragm pumps, one strives to To achieve optimum between stiffness and elasticity. A high elasticity of the membrane is needed so that the Membrane voltages are kept as low as possible. Especially in the high vacuum range, large pressure differences occur between membrane top and bottom. While on the Diaphragm top the respective evacuation process pressure usually acts on the diaphragm underside atmospheric pressure. As shown in Figs. 6 and 7 is, the conventional diaphragm pumps 106, 107 with Flat membrane (see Fig. 6) and with molded membrane (see FIG. 7), the lateral, particularly elastic ring zone becomes of these working membranes 1 by the atmospheric pressure during the intake phase in the direction of the delivery chamber. 2 bulged. By this "bulging" is the Creator volume reduced and thus the pumping speed these pumps 106, 107 reduced.

The diaphragm pumps 101, 102, shown in FIGS. 1 to 5, 103, 104 and 105 have in contrast to a highly elastic, a delivery chamber 2 limiting Working membrane 1 also an additional membrane 3, wherein between the working diaphragm 1 and the additional diaphragm 3 Membrane space 4 is provided. The in their outer Ring zones in the pump housing 5 firmly clamped membranes 1, 3 engage in their central area on the connecting rod one Pump drive on, the working diaphragm 1 and the Additional membrane 3 between a top dead center and a bottom dead center in the same direction oscillating back and forth emotional. Of the connecting rod of the pump drive is here only the Connecting rod 6 shown.

As is apparent from Figs. 1 to 5, which is in the Pump 101, 102, 103, 104 and 105 provided diaphragm gap 4 via a suction channel 7 with the suction side connected to these diaphragm pumps. For this purpose, in the in Figs. 1, 3 and 5 illustrated diaphragm pumps 101, 103 and 105 of Membrane space 4 via the suction channel 7 parallel to Delivery chamber 2 pneumatically connected to the pump inlet 8.

In the diaphragm pumps 102 and 104 as shown in FIGS. 2 and 4 the pump inlet 8 in contrast via the membrane gap 4 and the suction channel 7 with the delivery chamber 2 pneumatically connected.

Since in the case of the diaphragm pumps 101, 102, 103 shown here, 104 and 105 of the membrane gap 4 via at least one Suction channel 7 with the suction side of the diaphragm pumps pneumatically is connected, the membrane gap 4 is continuous evacuated, such that on top of the working diaphragm 1 and on the underside of the working diaphragm 1 during the Suction phase always prevail the same pressures. Because in the Suction phase thus no pressure difference between membrane top and -unterseite the working diaphragm 1 acts, the Working diaphragm 1 not in the direction of the delivery chamber. 2 bulge and an undesirable reduction of the Creator volume is avoided. By the bigger one Pump chamber volume can increase the pumping speed in the intake phase increase. This affects especially in print areas or Saugvermögensbereichen from nearby the final pressure are. The pressure differences only work the additional membrane 3, where it has no negative influence on the Suction capacity of the diaphragm pump 101, 102, 103, 104 and 105, respectively can have. As on the working diaphragm 1 of the diaphragm pumps 101 to 105 no differential pressure loads, this can Working diaphragm 1 are designed highly elastic without the mentioned "bulging" of this membrane 1 is to be feared.

In Fig. 4 it is shown that in the membrane space 4 of the Diaphragm pump 104 a Ansaugfilter- and Noise damping element 9 is provided. This Ansaugfilter- and noise damping element 9 is made of a elastic material, for example, from an open-pore Foam is made and on the one hand by the Working membrane 1 and on the other hand of the additional membrane 3 applied. This the membrane gap 4 substantially filling intake and noise damping element 9 is ring-shaped, wherein the annular opening 10 of the the membranes 1, 3 interconnecting connecting rod 6 of the Pleuels is interspersed. By in the membrane space 4 provided Ansaugfilter- and noise damping element. 9 Parts can be omitted and space saved and the Diaphragm pump 104 are made particularly compact.

In Fig. 5 it is shown that the working membrane 1 of the Membrane pump 105 a dimensionally stable membrane support 11th is assigned, which is held at the connecting rod 6 of the connecting rod. While in the single-stage diaphragm pumps 101 to 105 according to 1 to 5 of the membrane gap 4 in the suction phase is specifically used to increase the pumping chamber volume, will be in the ejection phase when the pressure on the membrane top continuously towards the atmospheric pressure increases, the diaphragm support 11 is used, which the Working diaphragm 1 of the diaphragm pump 105 on the back of the diaphragm at least in a central area form-adapted supported. As a result, the dead space volume is kept small.

In the membrane pumps 101, 102, 104 and 105 according to FIGS. 1, 2, 4 and 5, the membranes 1, 3 in the region of a central Holding opening 12, 13 at the connecting rod 6 of the connecting rod fixed clamped. Not only the additional membrane 3, but also the Working diaphragm 1 of the pumps 101, 102, 104 and 105 is as Flat membrane designed.

The working diaphragm 1 of Fig. 3 shown Diaphragm pump 103 is in contrast as a molding membrane educated. The working membrane 1 is with the additional membrane. 3 the diaphragm pump 103 via a central intermediate piece 14 to a double membrane 15 integrally connected. As shown in Fig. 3 becomes clear, has the intermediate piece 14 of the double diaphragm 15th on its side facing away from the delivery chamber 2 a undercut mounting hole in the one mating and with the connecting rod of the pump drive connected fastening part 16 is inserted. Despite the high elasticity of their working membrane 1 are the Diaphragm pumps 101, 102, 103, 104 and 105 by a high Absorbency without bulging in the intake phase this comparatively highly elastic working membrane 1 to would be afraid.

Claims (11)

1. Membrane vacuum pump (101, 102, 103, 104, 105) having a working membrane (1) that delimits a delivery chamber (2), and an additional membrane (3) arranged on the side of the working membrane (1) remote from the delivery chamber (2), and a membrane space (4) provided between the working membrane (1) and the additional membrane (3), as well as a pump drive for effecting an oscillating movement of the working membrane and of the additional membrane (1, 3) in the same direction, the membrane pump forming the first stage of a multi-stage pump or pump arrangement and the membrane space (4) being connected to the suction side of this membrane vacuum pump via at least one suction channel for evacuation and equalisation of the pressure in the membrane space (4) on the one hand and in the delivery chamber (2) on the other hand, the working membrane (1) being expanded at the top and bottom dead centres of its oscillating movement.
2. Membrane pump (101, 103, 105) according to claim 1, characterised in that the membrane space (2) is pneumatically connected to the pump inlet (8) via the minimum of one suction channel (7) parallel to the delivery chamber (2).
3. Membrane pump (102, 104) according to claim 1, characterised in that the pump inlet (8) is pneumatically connected to the delivery chamber (2) via the membrane space (2) and the suction channel (79).
4. Membrane pump (104) according to claim 3, characterised in that at least one suction filter and/or noise reduction element (9) is provided in the membrane space (4).
5. Membrane pump according to claim 4, characterised in that the suction filter and/or noise reduction element (9) is made of an elastic material and is acted upon by the working membrane (1) on the one hand and by the additional membrane (3) on the other hand.
6. Membrane pump according to claim 4 or 5, characterised in that the suction filter and/or noise reduction element (9) substantially fills the membrane space (4).
7. Membrane pump according to one of claims 4 to 6, characterised in that the suction filter and/or noise reduction element (9) is in the form of an open-pored foam element disposed between the working membrane (1) and the additional membrane (3).
8. Membrane pump (105) according to one of claims 1 to 7, characterised in that associated with the working membrane (1) is a dimensionally stable membrane support (11) which is held on a connecting rod of the pump drive and by virtue of its matching shape supports the working membrane (1) on the reverse side of the membrane at least in a central region.
9. Membrane pump (103) according to one of claims 1 to 8, characterised in that the working membrane (1) and the additional membrane (3) are integrally connected to form a double membrane (15).
10. Membrane pump (103) according to claim 9, characterised in that the working membrane (1) and the additional membrane (3) are integrally connected by means of a central intermediate member (11) and in that this intermediate member (11) comprises, on its side remote from the delivery chamber (2), an undercut fixing opening for the insertion of a fixing member (16) of matching shape, connected to a connecting rod of the pump drive.
11. Membrane pump according to one of claims 1 to 10, characterised in that the working membrane (1) is in the form of a shaped membrane.

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