Patent ID: 6068052
Filing Date: 2000-05-30
Classification: E21B,F04B

Abstract:
A tool connectable between the last sucker rod of a sucker rod string and a downhole pump comprising:a cylinder having a closed upper end externally adapted for connection to the last sucker rod of the sucker rod string, an internal annular seat proximate an open lower end thereof, at least one aperture through an upper side wall of said cylinder and at least one aperture through a lower side wall of said cylinder; anda piston reciprocally slidably and rotatively disposed within said cylinder and having a lower portion adapted for connection to the pump extending through said open end of said cylinder, said cylinder seat limiting a lowermost travel of said piston within said cylinder and said closed end of said cylinder limiting an uppermost travel of said piston within said cylinder, said at least one upper aperture venting well fluid from said cylinder as said piston reciprocates upwardly and said at least one lower aperture venting well fluid from said cylinder as said piston reciprocates downwardly.