HYDRAULIC DRIVE OF DOWN-HOLE PUMP Russian patent published in 2002 - IPC

FIELD: hydraulic machinery of volumetric displacement, drives including hydraulic or pneumatic means designed to lift fluids from great depth. SUBSTANCE: drive includes working cylinder 1 divided by piston 2 into piston 3 and rod 4 spaces, auxiliary tandem cylinder 5 with rod 6 and pistons 7 and 8 positioned on its ends and mounted on both sides of strap 9. Second piston space 11 of tandem cylinder 5 communicates through pipe-line 19, hydraulic distributor 15 with pump 16 and drain 17. EFFECT: enhanced operational reliability of pump installation thanks to reduced compressing force acting on rod of piston of working cylinder and string of bars in cases of rising resistance to travel of pump plunger. 2 cl, 2 dwg