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

FIELD: mechanized production of oil; sucker-rod pumps for production of viscous, high-viscous and light oils.

SUBSTANCE: proposed sucker-rod pump has cylinder, upper and lower moving hollow plungers, suction and discharge valves and filter with holes. Upper and lower plungers have similar diameters. Pump is additionally provided with hollow rod which is located between upper and lower plungers of similar diameter. Both ends of hollow rod are connected with stem passing through cavities of upper and lower plungers by means of perforated adapters. Upper end of rod located above upper end of upper plunger and lower end of rod located below lower plunger are provided with widening cone-shaped beads forming valves with plunger ends. Lower valve is used for delivery and suction. Fitted on rod between hollow rod and upper and lower plungers are perforated washers. Washers limiting inclination of rod are mounted in center of upper and lower plungers. Upper and lower plungers are made from elastic material.

EFFECT: avoidance of hanging-up of sucker-rod string during downward motion.

2 cl, 1 dwg