Positive displacement pumps vs. centrifugal pumps
The crucial, energy-saving advantage positive displacement pumps offer over centrifugal pumps when it comes to efficiency lies in their inherent higher overall efficiency, because of its closed and practically backflow-free design. The efficiency of a multiple-acting ABEL positive displacement pump is generally more than 80 % – independent of the operating point. Centrifugal pumps on the other hand, reach an efficiency between 20 % and 80 %; depending on how easily they reach the desired operating point.
In practice, poorer results – apart from the lack of a backflow-free centrifugal pump design – result from the fact that the design of many centrifugal pumps is either oversized or inadequate. Indeed, their best efficiency point (BEP) is frequently difficult to reach without the use of frequency converters. Apparently, for many companies it seems to be easier to accept higher energy consumption rather than to accept the centrifugal pump’s failure to fulfil its pumping tasks whenever it deviates from the best efficiency point. Due to their design, electricity-saving positive displacement pumps like the ABEL EM electric diaphragm pumps, do not have this significant problem of deviation from the BEP.
ABEL electric diaphragm pumps require less electrical energy than centrifugal pumps for two reasons. Firstly, thanks to their design, they generally have a higher efficiency, and secondly, they do not depend on reaching an optimum BEP in order to work efficiently, so they save on electricity and cost. This allows for a much more energy-efficient integration into a pumping system.