Pump

Abstract

A pump including a power rotor and an idler rotor, the rotors each being provided with a generally helical screw thread and being mounted for rotation in a housing such that the screw threads of the rotors mesh and rotation of one rotor causes rotation of the other rotor, the power rotor being connected to a driving means operation of which causes rotation of the power rotor, wherein the pitch of the threads is less than 1.6 times the outer diameter of the power rotor, the depth of the threads is less than or equal to 0.2 times the outer diameter of the power rotor, and the root diameter of the idler rotor is less than 0.31 times the outer diameter of the power rotor.

Dependencies are inferred from the claim text.