SUCKER ROD PUMPING UNIT Russian patent published in 2010 - IPC F04B47/00 

FIELD: oil and gas production.

SUBSTANCE: sucker rod pumping unit comprises sucker rod strings. A cylinder has superimposed steps of different diametre and a through passage in a bottom face of the step of greater diametre . The sucker rod string comprises two suspended hollow plungers of smaller and greater diametre coaxially coupled and movable inside the cylinder with inlet and discharge valves mounted in the plunger of greater diametre with its cavity connected with that of the cylinder by apertures. The maximum distance from the top end of the plunger of greater diametre to a junction point of the cylinder steps is equal to length of stroke of the plungers. A load is connected to the bottom end of the plunger of greater diametre and movable through the through passage. The load has an upper hollow part connected through the inlet valve with the cavity of the plunger of greater diametre . A filter is located in a hollow part of the load. A locking shoe is provided at the level of the through passage equipped with a scraper bushing. In full upper position of the plungers, a filter bottom is not higher than the scraper bushing.

EFFECT: more effective operation of the sucker rod pumping unit ensured by enhanced design and accordingly prolonged average runtime.

1 dwg