Oil well pump with self-contained lubrication

摘要

The oil well pump includes upper and lower seals at the upper and lower end portions of a plunger reciprocable within the pump barrel. Passages are provided in the wall of the plunger for introducing a lubricating fluid in the annular space between the outer wall of the plunger and the inner wall of the barrel between the upper and lower seals. These passages are subsequently sealingly closed to trap the lubricating fluid in the annular volume and thereby provide lubrication for the pump.