DIFFERENTIAL LONG-STROKE PUMPING UNIT Russian patent published in 2006 - IPC F04B47/02 

FIELD: production of oil from wells; drives of oil-well sucker-rod pumps.

SUBSTANCE: proposed differential long-stroke pumping unit is provided with differential crank mechanism used as transfer mechanism for forming rectilinear reciprocating motion of point of attachment of tightening pulley on drive crank. Transfer mechanism is mounted on output shaft of reduction gear on one side. Strut is mounted on the same side. Strut axis lies in vertical plane perpendicular to axis of reduction gear output shaft. Strut is provided with cross-piece with two guide pulleys movably mounted on its ends. Secured to lower part of cross-piece is flexible member embracing the tightening pulley movably mounted on drive crank, thus forming loop of pulley block with vertical branches; it is connected with rod carrier bar through guide pulleys mounted on strut cross-piece. Cranks interconnected through planetary gear train revolve in opposite directions. Length of stroke is non-adjustable and is equal to sum of eight radii of cranks. Strut cross-piece is turnable through 90° around strut axis or strut rolls away. Thus, rectilinear reciprocating motion of tightening pulley is obtained on drive crank; flexible member forms loop of pulley block; length of stroke imparted by crank mechanism is doubled and is equal to eight radii of cranks; strut is loaded only by compressive forces; inertial forces caused by rotation of cranks in opposite directions are mutually balanced; transversal swinging forces are absent; conditions are created for obtaining larger length of stroke and higher frequency of swinging per minute.

EFFECT: enhanced efficiency.

2 dwg