The specific flowrate of deviation function based lobe pumps––derivation and analysis

In this paper a general specific flowrate formula for lobe pumps is derived in terms of the pitch and deviation functions of a lobe. This formula applies to both circular and non-circular pitch curves. Pump lobes can be conveniently grouped according to the type of their deviation function. This formulation of flowrate provides a systematic and efficient tool for lobe pump design. A few classes of new lobe pumps with circular pitch curves are designed and evaluated.