GB428103A - Improvements relating to foam generation for fire extinguishing purposes - Google Patents

Abstract

428,103. Making foam. SODERBERG, C. W., c/o Aktiebolaget Pumpindustrie Askim, Gothenburg, Sweden. Jan. 12, 1934, No. 1236. [Class 47 (ii)] An apparatus for making foam comprises a mixing chamber 1 into which water under pressure from a pipe 2 is sprayed by a sprayer 3, such as a coarse-pitched screw thread, which imparts a rotary or swirling motion to the water stream and results in an increased pressure as the stream enters the chamber. A vessel 4 containing a foaming agent in liquid or powdered form is connected to the chamber 1 by pipes 5, 6, of which the pipe 6 extends into the space above the agent, so that the pressure in the mixing chamber serves to force out the agent. A gas intake 9 with a check valve 10 is connected to a source of compressed gas, preferably to the exhaust pipe of a motor. The exhaust gases may be additionally compressed, and the quantity of gas admitted is controlled by a valve. At the discharge end of the mixing chamber, a mixing member is provided comprising fixed pins 17 and rotary pins 16 driven by a propeller 15 or other means. Alternatively, a mixing member comprising wire nettings may be provided. In a modification, the pipe 6 may be connected to the source of compressed gas, or the gas and the water may enter the mixing chamber through the same inlet. The mixing chamber may be arranged at the end of a hose connected to the mixing chamber. In another modification, the mixing chamber is outwardly tapered.