Patent ID: 9316222
Filing Date: 2016-04-19
CPC Classification: E21B,F04B

Claim Text:
1. A double-action sucker-rod well pump comprising: a barrel, having a lower standing valve and connected to a pipe string with the use of a sub provided with an upper standing valve and an upper traveling valve, and a hollow plunger arranged in the barrel so as to form an under-plunger and an above-plunger cavities with the possibility of moving reciprocally, coupled with a hollow rod and having a lower traveling valve, characterized in that the barrel is made stepped with the lower step of a greater diameter and the upper step of a smaller diameter, the lateral wall of the plunger is provided with a through-hole above the lower traveling valve that is intended for communication between the plunger cavity with a chamber forming when the plunger moves downwards in the lower step of the barrel, the upper step of the barrel is made with an inner diameter that is less than the inner diameter of a pipe string, a sub is made with an inner diameter that is less than the inner diameter of a pipe string, but that is not less than the inner diameter of the upper step of the barrel, the upper traveling valve is made as a bush arranged on a rod with the possibility of moving along it longitudinally at an overpressure in the above-plunger cavity of the barrel and moving downwards in a liquid under its own weight, and is provided with a seat formed at the inner upper end of the sub, a stop being arranged on the rod between the plunger and the upper traveling valve and being made with the possibility of interacting with the upper traveling valve.