SCREENING DEVICE FOR HOLE Russian patent published in 2001 - IPC

FIELD: construction industry, operation of oil, gas or water wells. SUBSTANCE: proposed device can be used to grout well ( to control sedimentation processes ) or to inject water into well with installation of filter ( creation of favorable conditions for operation of filter ). Screening device includes hollow body and sealing unit with cylindrical part matched with it by means of sealing part. Device also has branch pipe placed outside of body and forming ring space together with the latter. Sealing unit is located on outer surface of branch pipe. Branch pipe has inlet circulation holes situated under sealing unit. They communicate space of well under sealing unit with ring space. Outlet circulation holes are located above sealing unit. They communicate ring space with space of well above sealing unit. The latter is so manufactured that its cylindrical part shuts off outlet circulation holes of branch pipe which are opened by flow of fluid coming from ring space. Outlet circulation holes in branch pipe are located at distance of 0.5-1.2 outer radii of cylindrical part from point of match of cylindrical part of sealing unit with its sealing part. EFFECT: simplified design of device, provision for its sinking into well with expansion of range of possible speeds of sinking, enhanced sealing of separation of ring space of well, raised operational reliability of device. 7 cl, 1 dwg