GB825444A - Method of purging the atmosphere of enclosed or confined spaces and for combating fires in such places - Google Patents

Abstract

825,444. Ventilating mines, tunnels &c. MINISTER OF POWER. April 30, 1956 [April 29, 1955], No. 12431/55. Class 137 [Also in Group XXI] A method of purging or replacing an atmosphere in an enclosed space, such as a tunnel or underground mine roadway, comprises generating a body of foam composed of bubbles which enclose the replacement atmosphere, across substantially the whole cross sectional area of the space, and causing it to effuse into the space whereby the atmosphere therein is progressively replaced by the growing body of foam so that upon collapse of the foam the space is left filled with the replacement atmosphere. In the exemplified embodiment water supplied from a main 4 mixed with wetting and foam stabilizing agents induced from a container 5 are sprayed on to an inclined mesh screen 2 of netted natural fibre yarn erected on a frame 3 across a section of a mine roadway. The normal ventilating current flowing in the direction indicated by the arrow A continuously converts the film of liquid mixture formed on the screen 2 into bubbles which coalesce into a foam 9 which effuses along the roadway under the influence of the ventilating current. The apparatus may be incorporated in a mobile unit which may be self propelled. The air current may be produced by a blower which may be driven by a power unit which serves also to drive the spraying device and as a prime mover for the mobile unit. The invention is also applicable to a method of combating a fire in an enclosed space (see Group XXI).