PLUNGER AND SEAL FOR WELL PUMP

摘要

A plunger or travelling valve and seal for a well pump and an oil well pump in particular, which plunger includes a mandrel of selected length, at least one plastic sleeve fitted with at least one metal insert mounted on the mandrel for sealing the mandrel in a pump barrel and a ball and seat valve provided on at least one end of the mandrel. The plunger may include fibre rings and ring holders and is seated inside a conventional pump barrel and the plastic sleeve serves to seal the plunger as the plunger reciprocates in the barrel. The plastic seal is typically constructed of ultra-high molecular weight polyethylene with one or two flanged, typically brass, inserts tightly mounted in the plastic seal bore to control or limit thermal expansion in the plastic seal.