An apparatus for generating foam includes a power source such as an internal combustion engine mounted in a frame for portable transportation of the apparatus. The power source drives an air compressor through an electric clutch which can disconnect the air compressor and a water pump. The water pump generates flow of the water under pressure through a duct system either to a water discharge valve or to a foam discharge valve. The foam is generated by injecting into the water stream a surfactant which is injected by reciprocating valve arrangement operated by flow of the water. The flow is controlled by a maximum flow orifice, a minimum flow orifice and an adjustable valve. The air compressor supplies a surge tank and the air is passed from the surge tank through a pressure regulator to a mixing device where the water and surfactant is mixed with the air to generate the foam. The mixing chamber comprises a vertical tube with a central shaft carrying a plurality of conical shaped baffles in spiral arrangement around the shaft.
Foam for suppressing fires is formed by mixing together a constant stream of compressed air and water from a pump at a controlled rate with a quantity of a foaming agent from a foaming agent supply proportional to the rate of flow of water so as to be incorporated therein. An agitator mixes the water and the foaming agent into the stream of compressed air to generate the foam. The rate of flow of the water is controlled by a continuously variable valve member driven between five set positions by an electronically controlled motor including a fully open position, in which a maximum flow rate of the water is supplied to the mixer with the proportional quantity of a foaming agent, a fully closed position, in which the flow of water and the flow of a foaming agent from the foaming agent supply are halted, and at least three intermediate positions of different foam characteristics.
A fire fighting fluid proportioning system and method including a fire fighting fluid conduit in fluid communication with a fire fighting fluid regulating valve and a venturi, the venturi in fluid communication with a valve source of fire fighting foam concentrate, and having a pilot valve connected directly or indirectly to the regulating valve and the concentrate source valve and adapted to adjust, directly or indirectly, the regulating valve and the source valve in response to a sensed indicia of fire fighting fluid pressure in the conduit.
A rotary nozzle for compressed air foam (CAF) has a barrel mounted for rotation about an axis perpendicular to its longitudinal axis. The barrel is mounted to a CAF supply conduit and has a cross-sectional area substantially larger than the cross-sectional area of the conduit. Two non-equal orifices in the barrel, located on the opposite sides of the axis of rotation, distribute CAF such that it covers an almost complete, typically a circular area on the ground.
The present invention provides new compressed air foam systems for use as firefighting equipment. One compressed air foam system has a water inlet connected to a water flow path through the compressed air foam system. A water and foam chemical mixer is flow connected to the water inlet and has a foam chemical inlet and a water/foam chemical outlet. An air compressor is provided which has an air inlet, an air outlet, and an air flow controller at the air inlet. A foam mixer is flow connected to the water/foam chemical outlet of the water and foam chemical mixer and to the air outlet of the air compressor. The foam mixer has a foam outlet which provides firefighting foam to a fireman's hose for application to a fire. A control system has a sensor in sensing relationship with the water flow path through the compressed air foam system for sensing water flow. The control system is operatively connected to the air flow controller of the air inlet to the air compressor to the amount of air provided to the water/foam chemical mixture by restricting inflowing air into the air compressor.
