REVERSE VALVE Russian patent published in 1994 - IPC

FIELD: boreholes casing. SUBSTANCE: reverse valve has: pipe 1 with mounted in it combined body 2, stepped central canal and by-pass canals in lower part of body; stopping from below body central canal chuck jaw 5, hinged to cantilever 3, using axle 4, in lower part of body 2. Chuck jaw is pressed to body 2 by spring 6. Covering bush 7 is mounted in central canal of body 2. Bush is connected with body 2 by shear bolt 8. By-pass canals are made in the form of blind holes, axes of which are in parallel to longitudinal axis of body 2, and radial holes 10, that cross them in lower part. Combined body has lower and upper radial canals. By-pass canals cross radial canals 13 and connect cavity of blind holes over pistons with cavity of casing string, that allows to make effective intermediate cleansing, required for lowering of casing string down to project mark without sticks in places. EFFECT: reverse valve is used in boreholes casing. 2 dwg 2