GB314438A - Improvements in and relating to foam-producing apparatus - Google Patents

Abstract

314,438. Friedrich, W. June 27, 1928, [Convention date], Fire-extinguishing by foam. - In an apparatus for forming foam by forcing a finely-divided gas under pressure into a foaming solution such as saponin, the gas is subdivided by passage through perforated metal plates, the solution passes the plates in an upwardly-directed stream, and the foam discharge pipe is relatively long. Nickel plates with openings of 0.05 millimetres diameter are suitable. The discharge pipe should have a length of two metres for a diameter of 20 millimetres, or of eight to ten metres for a diameter of 50 millimetres. The apparatus comprises a container 1 for the solution, to which gas under pressure is passed by a pipe 5, annular conduit 4, and ring-shaped perforated plate 3. Solution is passed to the container 1 from a reservoir 8 by a valved pipe 11, and is guided past the plate 3 by a conical baffle 7. A second pipe 12 leading to the top of the reservoir 8 ensures the presence of foam above the solution in the reservoir. Several apparatus may be arranged as a battery, and additional distributing plates 3 may be provided, for example on the baffle 7. In a modification, Fig. 2, the gas is distributed by a grid of perforated tubes comprising a header 17 and branch pipes 18. The latter may be formed of perforated plate, or may have large perforations 19 and be surrounded by finely perforated plate 20, Fig. 4. Several tube grids may be arranged one above the other, with their branch pipes in perpendicular, or oblique, relation.