SEALING UNIT FOR ASCENDING WEEP HOLE OPENING Russian patent published in 1995 - IPC

FIELD: mining engineering. SUBSTANCE: device has casing and slips with drive made in the form of hydraulic cylinders which rods are connected with the slips, tightening members for sealing the clearance between the casing and the slips and tightening members for sealing the clearance between the slips and drilling tubes. The tightening members for sealing the clearance between the casing and the slips are made in the form of flexible rings set into ring-shaped grooves on the rear part of the slips and on the internal side of the casing. The upper ring has trapezoid cross-section, which lesser base faces casing cavity. Beside that, the sealing unit has coating made in form of trapezoid plates fixed on the conic surface of the upper ring. EFFECT: improved operation properties. 2 cl, 3 dwg