LIFTING DEVICE HYDRAULIC DRIVE (VERSIONS) Russian patent published in 2007 - IPC F04B47/14 

FIELD: positive displacement hydraulic machinery.

SUBSTANCE: invention relates to hydraulic and pneumatic means and it can be used to set into operation sucker-rod well pump designed for lifting liquids from depth. Proposed hydraulic drive of lifting device contains working cylinder divided into two spaces by piston with rod. Balancing tandem cylinder with bridge and rod and pistons on its ends is installed to form four spaces, first of which, piston one, is connected with compressed gas reservoir, second, also piston one, is connected with lower space of working cylinder, and third and fourth spaces, rod ones, are connected by pipeline through hydraulic distributor with pump or drain. Upper space of working cylinder is connected by pipeline with pump and drain in parallel to rod space of tandem cylinder adjacent to its first piston space.

EFFECT: reduced downwards travel speed of working cylinder rod at preservation of sufficient speed of working cylinder rod and column string connected with it at upwards movement.

4 cl, 2 dwg