SWAB Russian patent published in 2001 - IPC

FIELD: oil-producing industry; construction of pistons for lifting liquids from wells. SUBSTANCE: swab is fitted with check valve and housing where stack of plates is mounted. Plates are made in the form of rigid metal members whose cross section has a form of truncated sector of circle. Working surfaces of flexible member and rigid metal members have a clearance equal to rigid metal members in swab housing in radial direction. Hole in swab housing is located at lower level of flexible member together with circular groove. While passing through narrow sections, rigid metal members are forced inside swab due to possibility of their travel in swab housing in radial direction and well fluid with mechanical admixtures is forced through groove and hole by flexible member inside swab. Liquids may be lifted in small amounts. EFFECT: increased productivity of swabbing. 1 dwg