System for automatic self-proportioning of foam concentrate into fire fighting fluid variable flow conduit

摘要

Apparatus for and a method of proportioning foam concentrate (FC) into a variable flow fire fighting fluid conduit (C) in which a first variable orifice (VWO) in the conduit (C) is arranged to maintain a predetermined pressure drop in the conduit less than a discharge pressure drop from the apparatus; a second variable orifice (VMO) in a foam concentrate conduit or inlet (FC1) is arranged to vary in concert with the first orifice such that the foam concentrate (FC) is proportioned into the fire fighting fluid (W).