SUCKER-ROD PUMP PLUNGER Russian patent published in 1998 - IPC

FIELD: mechanical engineering, construction of sucker-rod pumps. SUBSTANCE: sucker-rod pump plunger includes through cavity and sealing unit pressed by means of delivery pressure and provided with collars made from material deformable by this pressure; their section has form of equilateral trapezium whose lesser base is engageable with working surface of pump cylinder; each collar is separated from adjacent one by means of lock ring of volumetric configuration. Collar is provided with thin-walled bush located on side of larger base of trapezium symmetrically to it and made integral with collar manufactured from elastoplastic antifriction material, fluoroplastic for example. Plunger is provided with passages for communication of under-collar and through cavities. Thickness of collar over trapezoidal projection is equal to three or four thicknesses of thin-walled bush; trapezium angle ranges from 90 to 120 deg and ratio of thickness of thin-walled bush to its length ranges from 0.04 to 0.06. EFFECT: enhanced reliability. 2 cl, 3 dwg