James William Leach

US Patent:

49484320, Aug 14, 1990

Filed:

Nov 4, 1988

Appl. No.:

7/267384

Inventors:

James K. Leach - Long Beach CA

Assignee:

Pacific Alloy Castings, Inc. - South Gate CA

International Classification:

C21D 504

US Classification:

148 3

Abstract:

A rotor for a progressive cavity pump comprises an elongated metal bar having a helical recess formed in its outer surface and progressing along the length of the rotor. The rotor is made by casting the metal bar generally in the shape of the rotor with the helical recess being formed in the outer surface of the resulting casting. The casting is made from an abrasion-resistant cast iron such as the family of cast irons available under ASTM designation A 532. The casting is then optionally subjected to an annealing step, followed by machining the outer surface of the casting to the finished shape of the rotor. The machined rotor is then heat-treated for strength and hardness. The finished rotor has a substantially longer wear life, when used to transfer abrasive fluids in a progressive cavity pump, when compared with a conventional rotor made from a chrome-plated steel alloy.