Screw pump
AssigneeBühler Motor GmbH
InventorsRobert William Beaven, Michael John Werson
Life of this patent
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Abstract
A pump including at least three rotors each being provided with a generally helical screw thread, the rotors 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, wherein the pitch of the threads is less than 1.6 times the outer diameter of the rotors or where one of the rotors has a larger outer diameter than the other rotors the outer diameter of the larger diameter rotor.
Claims9
A pump including three rotors each being provided with exactly two generally helical screw threads, the rotors being arranged such that a central rotor is located between the other two outer rotors, and the screw threads mesh such that the rotation of one rotor causes rotation of the other rotors, wherein the outer diameter of the central rotor is larger than the outer diameter of the two outer rotors, the pitch of the threads is less than 1.2 times the outer diameter of the central rotor and is substantially constant along the entire axial length of the rotors, and the thread depth of the screw threads is less than 0.2 times the outer diameter of the central rotor.
Dependencies are inferred from the claim text.