HYDRAULIC DRIVE SYSTEM FOR DEEP-WELL OIL PUMP Russian patent published in 1998 - IPC

FIELD: oil industry. SUBSTANCE: hydraulic drive system 300 for driving oil pump bar has main piston 358 positioned within main cylinder 356 for axial reciprocation between first and second end sections of main cylinder 356. Main piston 358 has drive piston stem 364 extending through one end of main cylinder 356. Drive stem 364 is connected with crankpin 347 of eccentric crank 344 which is driven at constant rotational speed for transmitting reciprocal motion to main piston 358 within main cylinder 356 in sinusoidal rhythm. Central sealing unit 368 divides main cylinder 356 into working chamber 370 and pressure chamber 372 positioned in opposite ends of main cylinder 356. Each chamber defines liquid volume variable upon displacement of main piston 358. Movement of main piston 358 provides bidirectional flow of working fluid from working chamber 370. Mouth hydraulic unit 311 is connected with oil well pump bar and hydraulically communicated with working chamber 370 of main cylinder 356 to receive working fluid flow. In response to working fluid flow mouth hydraulic unit 311 causes reciprocal motion of oil well pump bar in rhythm comparative to motion rhythm of main piston 358. Gas tank 376 is hydraulically communicated with pressure chamber 372 of main cylinder 356 to move main piston 358 to end working section of main cylinder 356 and create ascending shear force at mouth hydraulic unit 311. EFFECT: increased efficiency, enhanced reliability in operation and prolonged service life. 36 cl, 13 dwg