SUCKER-ROD PUMPING PLANT Russian patent published in 2001 - IPC

FIELD: oil producing industry; viscous oil production. SUBSTANCE: plant has pump with two-step cylinder accommodating two hollow plungers of different diameters which are connected to each other, thus forming working chambers. Lower step of plunger has weight installed outside the pump lower than its intake part. Distance between upper end of larger diameter plunger and place of cylinder coupling is equal to length of plunger stroke. Reliability of socker-rod pumping unit is improved owing to reduction of hydrodynamic losses by provision of synchronous movement of pumped out liquid and rod string in direction at upwards movement and elimination of rod hanging up. EFFECT: improved reliability of operation. 1 dwg