METHOD AND DEVICE FOR ELECTRIC THERMAL DRILLING Russian patent published in 1994 - IPC

FIELD: drilling technique. SUBSTANCE: method for electric thermal drilling includes warming up the ground till it softens by a device having a head and a cylindrical part and lifting of the ground. The softened ground is destructed by cutting. Then the ground is risen to the height of the cylindrical part and warmed up to the melting temperature. The device includes head 1 having thread 2 on its external parabolic surface and cylindrical part 3. Device is provided additionally with thermal insulation 6 and magnetic crystallizer 7. The additional thermal insulation is disposed above cylindrical part 3 of the device and the crystallizer is placed above the additional thermal insulation. Head 1 has a parabolic working surface having a cutting edge on the thread. Calibrating ribs 4 made in the form of a multiple thread are made on the external surfaces of the cylinder part and additional thermal insulation. The cylinder part is higher than the head. A package of thermal insulating gaskets are disposed above the working head. The additional thermal insulation is higher than the thermal insulating gasket package. EFFECT: enlarged operating capabilities. 5 cl, 3 dwg