Session: 01-02: Pumps and Motors 1: Piston and Membrane Machines

Paper Number: 140056

140056 - Energy Efficient Pneumatic Drive for Membrane Pumps 

Abstract: 

Membrane pumps are frequently employed for liquid pumping under various conditions. Advantageous of the design is an absence of the need for lubrication and moving seals, making the pumps very robust. This makes them particularly suitable for use in the food processing and pharmaceutical industries and allows use with abrasive liquids. Although the pneumatic drive allows operation in potentially explosive environments, for example, it also requires a considerable amount of energy. In the scope of this paper, a novel efficiency optimization method of pneumatically driven membrane pumps is therefore presented.

The present work aims to reduce the compressed air requirement in applications, which require lower fluid pressure compared to the pneumatic supply. Previous work using a bi-stable mechanism for compressor applications has already been proposed by the authors. In (Schmid, 2022), the optimal characteristic of such mechanism is deduced from the pressure profiles of the drive chamber of a pressure booster. (Reinertz, 2019) also uses this approach to optimize vacuum pumps.

For the current application, the thermodynamic effects during operation of the membrane pump are first examined analytically. The equations of motion are introduced by illustrating of the acting forces in free body diagram. The movement behavior is mainly influenced by the pressure profile of the pneumatic actuator. The installed membrane has furthermore a considerably non-linear force-displacement profile. This is examined in more detail using (Schomburg, 2015) analytical approaches. The main differences between gas compression and the pumping of liquids are highlighted. In this way, the energy saving potential compared to the conventional device is investigated. Based on a dynamic lumped parameter model in DSHplus the ideal behaviour of the bi-stable mechanism is determined. The load profile is then integrated into the dynamic simulation and used to validate the energy-saving potential. The evaluation is based on the pressure profiles in the drive chambers and the compressed air consumption.

Finally, an approach for design conversion of the bi-stable mechanism to integrate in a membrane pump is presented. The geometry of the bi-stable mechanism is investigated in a FEM-simulation. The mechanism is based on the effect of mechanical snap-through and is modeled as a "thin shell" with large deformation. The simulated force curve (equal to load profile) of the mechanism is compared with the optimum load profile. In addition, the force curve of the mechanism is integrated into the DSHplus model to show the increase in efficiency that can be achieved.

 

 

Reinertz, O. (2019). A Novel Exergy Efficient Pneumatic Vaccum Pump. SICFP, (p. 12). Tampere.

Schmid, M. (2022). Development of a Bi-stable Mechanism for Efficiency Optimization of Pneumatic Pressure Boosters. GFPS, (p. 6). Neapel.

Schomburg, W. K. (2015). Introduction to Microsystem Design. Berlin, Heidelberg: Springer-Verlag.

 

Presenting Author: Matthias Schmid Institute for Fluid Power Drives and Systems

Presenting Author Biography: Matthias Schmid received the bachelor's degree in mechanical engineering from Stuttgart University in 2016, the master's degree in mechanical engineering from Stuttgart University in 2020. He is currently working as a Research Associate at the Institute for Fluid Power Drives and Systems (ifas), RWTH Aachen University. His research areas include optimization of pneumatic systems focusing on energy efficiency and performance.

Authors:

Matthias Schmid Institute for Fluid Power Drives and Systems
Olivier Reinertz Institute for Fluid Power Drives and Systems
Schmitz Katharina Institute for Fluid Power Drives and Systems