BOREHOLE ELECTRICALLY-HYDRAULICALLY DRIVEN PLANT Russian patent published in 2001 - IPC

FIELD: oil production. SUBSTANCE: pump unit has hollow plunger coming in the form of two sections of different diameters with suction and pressure valves mounted in cylinder for reciprocating motion. Upper and lower chambers are formed in cylinder. Upper chamber has hole shut off by pressure valve and lower chamber has one hole as minimum which is used to communicate with space of plunger that is connected through suction valve to container of fluid to be pumped over. Section of plunger of larger diameter can be positioned in upper and lower chambers and section of plunger of smaller diameter can be located in lower chamber. Space of plunger is divided by one intermediate valve as minimum. EFFECT: raised discharge of oil wells with high gas factor. 2 cl, 1 dwg