Patent attributes
Fire fighting equipment uses an electronically controlled direct injection foam delivery system. A water pump pumps water through a pipe. A foam pump pumps foam into a mixing chamber within the pipe to produce a water-foam mixture. A microprocessor-based control unit controls the water pump and foam pump. A conductivity sensor is coupled in-line with the pipe for monitoring conductivity of the mixture and providing a feedback signal to the control unit to regulate the foam pump. A speed sensor monitors the foam usage. A second conductivity sensor monitors conductivity of the water and provides a feedback signal to the control unit. The foam delivery system can be controlled by monitoring the flow rate of the water and regulating the foam pump to maintain a constant water and foam mixture. A temperature sensor compensates the regulation process for changes in water and foam mixture temperature.
