BOTTOM-HOLE OIL PUMP OF DOUBLE ACTION Russian patent published in 2011 - IPC F04B47/00 

FIELD: engines and pumps.

SUBSTANCE: pump includes cylinder having lower suction valve and connected to pipe string by means of adapter equipped with upper suction and discharge valves, and hollow plunger arranged in cylinder so that under-plunger and above-plunger cavities are formed and with possibility of back-and-forth movement, which is connected to hollow rod and having lower discharge valve. Cylinder is stepped and has lower step of larger diameter and upper step of smaller diameter. In side wall of plunger above lower discharge valve there made is through hole for connection of plunger cavity to the chamber formed at its movement downwards in lower step of cylinder. Upper step of cylinder has inner diameter that is smaller than inner diameter of pipe string. Adapter has inner diameter that is smaller than inner diameter of pipe string, but not smaller than inner diameter of upper step of cylinder. Upper discharge valve is made in the form of bush located on rod with possibility of upward longitudinal movement along it at excess pressure in above-plunger cavity of cylinder and downward movement in liquid under empty weight, and is equipped with the seat formed on upper inner edge of adapter. Between plunger and upper discharge valve on the rod there arranged is the stop having the possibility of interaction with upper discharge valve.

EFFECT: higher operating reliability of pump.

2 cl, 2 dwg