MULTIPURPOSE GEAR FOR PREVENTION AND FIGHTING UNDERGROUND FIRES THROUGH BOREHOLE Russian patent published in 1994 - IPC

FIELD: mining industry. SUBSTANCE: multipurpose gear has ejector 1, heat exchange chamber 2 and chamber for mixing pulp with foam generator. Pulp is fed over pulp feed-line 22 through branch pipe 16 and gate valve 23 into pipe-cross 15. Part of pulp from it is directed through branch pipe 21 to next borehole and the other part is fed into mixing chamber 19 where it is mixed with foam generator. Liquid nitrogen is fed through branch pipe 4 anchored tangentially into labirinth duct 5 where it evaporates actively and is injected in the form of vapour and gas mixture into flow of pulp coming out of ejector 1. Holes 8 are oriented to section of casing pipe 24 close to wall. Jets of inert gas escaping from them under pressure form gas lubrication over starting section of borehole 25 which facilitates foaming of pulp and reduces hydrodynamic resistance to pulp stream. EFFECT: increased foam formation. 2 dwg