The Double Channel Membrane Pump 

The working principle:
Using an analogy to electromagnetic wave propagation Wilhelm ZACKL invented a new valve less pumping principle. A channel with  rigid walls is divided in its mid plane into two sub-channels. On the inflow- side (left in figure 1) the sub-channels are separated by a rigid plate.   On the outflow side the sub-channels are divided by a membrane which is attached to the rigid plate. The inflow part of the pump is called reflection pipe or reflection channel. The outflow part is called wave pipe or wave channel. The length of the reflection channel  is about one half of the length of the wave channel. At the beginning of the wave channel waves are excited by displacing a certain volume DV of fluid periodically. In  figure 1 three different propulsion mechanism are  shown.

 Vertically oscillating propulsion plate: The membrane is displaced vertically by an oscillating propulsion plate  (figure 1a ).  In figure 2 a demonstrator model in operation is shown.

Turning flap: At the end of the reflection channel there is a flap which turns periodically up and down. The membrane is attached to this flap, see figure 1b. This design principle has been used for a prototype pump (figure 3).

Reciprocating pistons at top and bottom: In  figure 1c)  the volume is displaced by two pistons acting on the bottom an top surface of the channel to displace the volume DV Here the membrane reacts  passively to the induced pressure perturbations in both sub-channels. This design principle seem to be the simplest in terms of production. 

However, all three pumps design work according to the same principle:  The displacement of the volume excites a wave on the membrane. This wave travels towards the outflow side (in figure  1 to the right) of the pump. This wave is the result of the  interaction of the (periodically excited) membrane with the fluid in both channels.  As a result this wave causes a net fluid flow through the pump.  In figure 2 a pump according to the design principle in figure 1b   is shown.    The blurred trace of small particles indicate the motion of the  fluid. The wave with an amplitude of 80 percent of the (half) channel width  travels from left to right. 

Figure 1: Working principle

Figure 2: Demonstration model. Membrane is excited by vertically oscillating propulsion plate.

Movie

Wilhelm Zackl, Harald Neth and  Heinz Marek have built a test pump for a first experimental investigation. The pump has been integrated in a test loop. (figure 3). I turned out the design of the membrane has a significant influence on the performance of the pump. The membrane of the test pump is shown in figure 4.  The experimental investigation has been financed by FLOWSERVE AUSTRIA  and  the FFG.

 

Figure 3: Test pump .

Figure 4: The membrane of the test model. Membrane is excited by a turning flap.

Applications
The main advantage of valveless pumping is that fluids with relatively large solid particles (stones, movie) can be pumped. Thus applications in waste water treatment, chemical and food industry are possible.

A second field of application is the propulsion of water vehicles in shallow water. Figure 5 shows a model boat with a Double channel membrane pump as propulsion mechanism.

Figure 5: Model boat with Double Channel Membrane Propulsion Mechanism

Movie

W. ZACKL holds in several countries patents  on the Double Channel Pumping and Propulsion Mechanism.

Future Work
Theoretical Investigation of the flow field in the double channel membrane pump. The challenge will be the interaction of the fluid flow in the channels with the membrane where new methods for the numerical simulation of the fluid structure interaction will be developed

Experimental investigation: The internal flow field of the pump will be measured using PIV (Particle Image Velocimetry) and new improved pump and propulsion designs will be developed.

For more information please contact
Herbert Steinrück
Inst. of Fluid Mechanics and Heat Transfer, TU-Vienna, Tel. +43.1.58801.32232, E-Mail: herbert.steinrueck(at)tuwien.ac.at
Peter Heimerl
Department of Technology Transfer, TU-Vienna,  +43.1.58801.41532, E-Mail: peter.heimerl(at)tuwien.ac.at
Wilhelm Zackl
Patent holder Tel: +43 676 537 4915,  E-mail  jr(at)kabsi.at

Movies:      Membrane waves (90 MB)
                    Pumping stones (17 MB)
                    Boat propulsion   (6 MB)

see also: Außeninstitut der TUWIEN

Picture gallery