Energy Efficient Pneumatic Drive for Membrane Pumps

BATH/ASME Symposium on Fluid Power and Motion Control (FPMC)

Abstract

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 in applications with abrasive liquids. Although the pneumatic drive allows operation in potentially explosive environments, for example, it also requires a considerable amount of energy. The present work aims to reduce the compressed air requirement by increasing the efficiency. Firstly, in this paper, losses in current systems are highlighted. The significance of actually unused expansion energy is explained and an approach for its utilization is introduced. In this context, the modification of the system with an upstream throttle is also described. This is particularly important with regard to the new type of mechanism for efficiency optimization, which is presented next. It consists of a spring with negative spring stiffness, which is used to utilize the expansion energy. This suppresses the expansion during the first motion interval, temporarily stores and releases its energy during the stroke. This supports the displacement and reduces the pressure requirement in the drive chamber over the stroke. By means of a lumped parameter simulation, the usual operating conditions with downstream throttling and pressure reducer are examined. The results are compared to the variant with upstream throttling and the new concept with a bistable mechanism. The results validate the huge potential for compressed air savings up to 85 % at an average of 60 %.

Authors 3

1. Matthias Schmid Aachen Institute for Fluid Power Drives and Systems

   RWTH Aachen University

   Affiliation as printed

   Institute for Fluid Power Drives and Systems , Aachen, Germany

2. Olivier Reinertz Aachen Institute for Fluid Power Drives and Systems

   RWTH Aachen University

   Affiliation as printed

   Institute for Fluid Power Drives and Systems , Aachen, Germany

3. Katharina Schmitz Aachen Institute for Fluid Power Drives and Systems

   RWTH Aachen University

   Affiliation as printed

   Institute for Fluid Power Drives and Systems , Aachen, Germany