Abstract: The eccentric disc pump has a series of stator discs defining a series of axially interconnected pump stages each having a rotor disc mounted eccentrically on a common shaft extending within central cavities of the stator discs and angularly offset relative to the rotor disc of a preceding pump stage, adjacent stator and rotor discs being angularly offset one relative to the other at given angles of displacement and coupling means, e.g. rods, wedges and grooves or studs and recesses, respectively engaging each stator disc with that of an adjacent pump stage and positively locating such adjacent stator discs in positions, offset by a second angle one half of the first mentioned angular displacement between corresponding adjacent rotor discs whereby in each pump stage the cavity of the stator disc forms an enveloping curve for the path of the rotor disc rotatable therein.

Abstract: An eccentric worm pump in which a helical worm rotor rolls off in a planetary manner in a multi-thread hollow helix of a stator sleeve. The helix is adapted to its cross-section and its pitch. Closed helical cavities between the rotor and the opposite part of the helix, are formed and moved from an intake end to a delivery end of the stator sleeve. A plurality of interchangeable annular wearing elements are arranged staggered axially in the roll-off track between the rotor and the stator. The wearing elements may be in the form of collars fixed relative to one another and rotatably adjustable axially relative to the rotor. The collars are braced by a reset device attached to the free rotor end between ring shoulders. The collars have an outer surface which rolls off in the hollow helix and has a layer of elastically resilient wearing material. The wearing material is in the form of a wear-proof sliding synthetic substance.