Abstract: A compressed air/foam fire fighting system which is sufficiently compact to be carried on the bed of a pick-up truck includes a water tank, a pump for providing water at substantial pressure to a water conduit, an engine for driving the pump, a foam reservoir including a bladder tank connected to the pump, an air compressor, an engine for driving the air compressor, a differential pressure valve connected in the water conduit, a metering valve adjustable to supply a desired proportion of foam concentrate to water connected across the differential pressure valve, an air valve for controlling the amount of air from said compressor, and an air injection venturi for mixing air into a water/foam concentrate. A two-way valve connected between the tank and the pump is movable between a first position where water is pumped from the water tank and a second or suction position where water is drawn from an outside tank or other source.

Abstract: A nozzle assembly for aerating a pressurized liquid stream to produce a discharge of foam includes a plurality of arcuate venturi throats in a circular arrangement around the center of the nozzle together with a radial air inlet to each throat which is adjustable by relative rotation of the inlet coupling and the venturi housing. Additional turbulence may be created by a screen downstream of the venturi throats and secondary air may be admitted at that point.

Abstract: A fire fighting foam proportioner for use in providing precise proportioning of foam to fire fighting liquid, e.g. water, is disclosed. It includes a tank for the storage of foam concentrate which is loaded using a hand pump. The storage tank is coupled to a fire fighting line through a differential pressure responsive valve in the fire fighting line and a proportioning valve used to select the foam concentration desired, for example 0.2 to 1 percent of the fire fighting liquid. The differential pressure responsive valve applies discharge pressure to the foam concentrate as a function of the fluid flow through the line and therefore provides precise flow concentration maintenance despite changes if flow and line pressure. The differential pressure responsive valve includes to coaxial valving members and low and high pressure ports which are coupled to control the discharged pressure to the tank. The proportioner valve include a rotor with a continuous variable groove for precise control.