OIL WELL PUMP WITH EXPANSION TANK (VERSIONS) Russian patent published in 2007 - IPC F04B47/04 

FIELD: pumps for handling fluid media of wells.

SUBSTANCE: proposed pump has casing with hydraulic drive arranged inside it. Hydraulic drive includes cylinder with rod connected with actuating fluid passage. Drive includes also head part with at least one tank divided by elastic diaphragm into cavities of varying volume for actuating fluid and fluid to be pumped-out; diaphragm may be locked in extreme positions for connection of actuating fluid cavity with actuating fluid passage and cavity of fluid to be pumped-out with cavity of casing. Cavity of casing is provided with suction and delivery valves for communication of cavity of casing with source and discharge passage of fluid to be pumped-out. Pump is also provided with expansion tank connected with actuating fluid passage. According to first version, expansion tank is made in form of cylindrical reservoir divided into two chambers by piston; cylindrical reservoir is provided with spring pressing the piston to hole connecting the first chamber of reservoir with actuating fluid passage. Reservoir has cover which is used for control of spring tension; second chamber of reservoir is communicated with cavity of casing. According to second version, expansion tank is made in form of reservoir with inlet and outlet valves. Inlet valve is provided with plate pressed to inlet by spring; it is divided by elastic membrane or piston connected with plate into two cavities: first cavity contains plate and branch pipe connecting the valve with reservoir and second cavity is connected with cavity of casing.

EFFECT: avoidance of necessity of lifting the pump at warming-up well; avoidance of losses of delivery after exposure to high temperature.

6 cl, 5 dwg