DIFFERENTIAL SUCKER-ROD PUMP Russian patent published in 2006 - IPC F04B47/00 

FIELD: oil producing industry.

SUBSTANCE: invention relates to differential sucker-rod pumps and it can be used for pumping out high-viscosity liquids. Proposed differential sucker rod pump has cylinder coupled with tubing string which accommodates differential plunger coupled with sucker-rod string. Upper step of larger diameter plunger with mechanical seal has through channel, being equipped with delivery valve, and lower step of smaller diameter plunger is made in form of solid rod. Ring space enclosed between walls of cylinder and surface of rod forms working chamber of pump with suction valve made in form of plate with hole coaxial with cylinder through which solid rod is passed, being provided with mechanical seal. Intake filter in form of perforated cylindrical tube is installed lower than suction valve. Solid rod passes inside intake filter along its axis, and on its lower part piston is installed mechanically sealed relative to inner wall of intake filter. Perforation of cylindrical tube is made in form of conical holes or longitudinal slots widening in direction from axis of filter.

EFFECT: improved reliability and efficiency of operation of differential sucker-rod pumps.

2 cl, 1 dwg