Stator casing where the inner surface faces form a polygon and each face has a groove to reduce friction

摘要

A stator casing (10) for an eccentric worm pumps is disclosed. The stator casing (10) includes an inner surface (12) consisting of a series of inner surface faces. The inner surface faces are arranged so that, in a cross-section of the stator casing (10) in a plane perpendicular to the longitudinal axis, the inner surface forms a polygon. At least one of the inner surface faces includes at least one groove (16) which reduces the adhesive effect between the stator casing (10) and an elastic lining which moves axially within the casing.