PISTON OF OIL-WELL SUCKER-ROD PUMP Russian patent published in 2001 - IPC

FIELD: hydraulic and pneumatic machines at reciprocating motion of working members. SUBSTANCE: piston has contact slotted seal mounted in housing and made in form of sealing rings lapped to each other over end surfaces and pressed to surfaces to be sealed by means of flexible holder. Outer surface of holder is provided with eccentric beads; sealing rings having concentric cylindrical surfaces are located on these beads. Sleeve with flexible base is mounted under lower ring of contact slotted seal resting against this seal and end face of flexible holder, thus performing function of additional slotted seal. Sleeve is provided with solid wear- resistant coat made from ceramics, for example. Sleeve is located in spaced relation to housing covered with flexible base on either side. EFFECT: enhanced reliability of piston. 1 dwg