Ronald W Cobb

US Patent:

60659440, May 23, 2000

Filed:

Sep 12, 1997

Appl. No.:

8/928141

Inventors:

Ronald F. Cobb - Houston TX

International Classification:

F04B 4500

US Classification:

417394

Abstract:

A pump having a semi-rigid flexible outer tube with a sealed top and a sealed bottom, check valves at the top and bottom such that the outer tube is in fluid communication with the working fluid, an inner tube concentrically disposed within the outer tube, and a controlled source that applies pressure to expand the inner tube to apply a force to the working fluid in the annulus defined by the inner and outer tubes is used to pump viscous materials and/or slurries from the bottom of small diameter wells. The tubes are made from nonmetallic, elastic materials and can be inexpensively manufactured.