NON-RETURN WASHING VALVE Russian patent published in 1997 - IPC

FIELD: oil production industry. SUBSTANCE: this relates to well head equipment and can be used in oil production wells operated with immersed pumps. Non-return valve has body with upper and lower connecting threads. Body hollow is covered atop by baffle grate. This hollow communicates with outside space through side passage having vertical section. Also made in body is longitudinal passage communicating with hollow. Installed in vertical section of side passage and in upper part of longitudinal passage are seats in the form of taper bushes having cylindrical sections in their lower parts. Located in hollow is ball-type valve which can be found in one or other seat and in changing direction of fluid flow motion, ball-type valve can replace from one seat to other. At running down of pumping unit at speed of 0.15-0.25 m/s, ball-type valve being on seat in side passage only lifts up to pass fluid from intertube space into lifting tube string. Taper bushes can be installed at one level and fixed in passages by thread made on cylindrical sections and correspondingly in mating sections of passages. Baffle grate has concave lower surface and radial protrusions over periphery for centering in circular bore of body. Vertical slots are provided in thread for passing of protrusions when installing grate into bore. At lifting of equipment, pump is isolated by ball-type valve. EFFECT: high efficiency. 4 cl, 1 dwg