GB441441A - Improvements in and relating to the production of foam such as is used for fire extinguishing purposes - Google Patents

Abstract

441,441. Making foam. PYRENE CO., Ltd., Great West Road, Brentford, Middlesex. May 23, 1935, No. 15092. Convention date, June 23, 1934. [Class 47 (ii)] In apparatus for making foam of the type in which a jet of foam - forming liquid under pressure draws inthe necessary air for foam formation, means is provided for imparting a rotary motion to the jet as it is discharged into a conduit in which it mixes with the induced air. As shown, a water pipe a terminates in a nozzle b within which twisted blades c are arranged. The rotary jet of water, to which foaming agent has been added previously, expands in the conduit i and the necessary air is drawn in at openings k arranged adjacent the nozzle at the point where the pressure is lowest. In a modification, water alone is forced through the nozzle b, and draws in the necessary foaming agent in addition to the air. Truncated conical baffles are arranged in the conduit i to assist in mixing the liquid and air. In another modification, Fig. 3, the conduit i is carried by struts p from a sleeve n which is screwed on to the pipe a and comprises a subsidiary nozzle d<1>. The latter co-operates with the main nozzle b<1> to form a suction chamber e, into which foaming agent is drawn from the pipe f. Adjustment of the sleeve on the pipe a controls the supply of foaming agent. Spaces k are provided in the struts p for the entrance of air, and the struts have projecting flanges to prevent accidental closing of the spaces k. Mixing baffles l<1> provided in the conduit i are inwardly inclined and serrated. The pipe f is arranged to be quickly detachable from the source of foaming agent. The twisted blades c may be replaced by spiral grooves or ridges or screw-like members. Specification 272,993, [Class 47 (ii)], is referred to.