DEVICE FOR FORMING DIRECTED FRACTURES IN BOREHOLES Russian patent published in 2001 - IPC

FIELD: mining. SUBSTANCE: device may be used in formation of oriented fractures by fluid fracturing of rock through borehole to separate into layers of difficult-to-cave roofs, coal seam degassing, control of stressed-deformed state of rock mass in surroundings of mine working. The device includes hollow cylindrical body with circular protrusion on external surface, end channel for supply of working fluid and hole for its discharge, sealer in the form of tube coaxial to body and having circular stop on end and sealing sleeve made of monolithic material which is transformed into loose state under action of external load. Tabs of disc spring, fitted on tube between its circular stop and sealing sleeve are used as movable apart members with transverse pin-up wedges. Tube with end free from stop is installed into cavity of cylindrical body whose circular protrusion is made on end and comes in contact with sealing sleeve. EFFECT: higher efficiency of device operation. 2 cl, 3 dwg