Patent ID: 6497561
Filing Date: 2002-12-24
Classification: F04B

Abstract:
A reciprocating plunger for use with a sucker rod string driven reciprocating plunger and stationary housing subsurface pump system including a polished rod at the surface end of said sucker rod string and a standing valve mounted on the bottom of said stationary housing, said reciprocating plunger comprising:a tubular member constructed and arranged to form a variable length fluid seal with said stationary housing; said tubular member having a length which extends outwardly from within the stationary housing; said tubular member having a diameter which is less than or equal to the diameter of the polished rod; said tubular member including a traveling valve mounted to the bottom thereof; whereby when said tubular member is moved downwardly into the stationary housing subsurface fluid is pushed out of the stationary housing and when said tubular member is moved upwardly out of the stationary housing no subsurface fluid leaves the stationary housing.