SWAB Russian patent published in 1997 - IPC

FIELD: oil producing industry; deep-well pumping units for lifting liquids from wells. SUBSTANCE: swab has housing with check valve provided with circular beads which are used to limit radial motion of sealing members mounted on housing. Radial motion of sealing members is ensured by means of washer fitted above upper circular bead; washer is provided with radial projections received by mating grooves on upper ends of sealing members. Inner sides of sealing members are provided with recesses; slots available at sides are used to receive bridges whose lateral projections enter the above-mentioned recesses. Flexible collar is located between sealing members and housing; chamber between this collar and housing is brought in communication with cavity of pump tubing above swab through upper sections of clearances between sealing members. EFFECT: enhanced reliability. 3 cl, 3 dwg