Research And Design Of The Automated Fire Fighting Compressed Air Foam System

With the continuous development of technology and the steadily increasing petrochemical enterprises, ports, inflammable product warehouses and high-rise buildings in China. Fire becomes one of the disasters which threaten people’s life and property seriously. As a rapidly evolving fire-fighting technology, compressed air foam system, which contracts to CAFS, is becoming increasingly concerned. Based on the different foam producing mechanism and process compares to traditional air foam technology, compressed air foam system has a higher momentum and strong stability, less amount of water, excellent water retention properties, good thermal-radiation blocking ability, good moist advantages and higher efficiency of fire suppression.In the design and implementation of the compressed air foam system, based on the functional requirements, design principles, the foam proportioning system and air balance system was designed. Further more, the framework of integrated compressed air foam system which includes tube road, control, power and other units were formed. Two important proportions of the foam mixing ratio of0.1%to6%and the air mixing ratio of1:1～20:1were identified.Based on these, the hardware and software of the integrated control unit of foam proportioning system and air balance system was designed. According to the function requirements of control unit as well as its main controller’s operating speed, the main chip PIC18F8723was selected.The hardware which includes power module circuit, buttons and digital display circuit, signal acquisition circuit and control output circuit; the software design completes the acquisition of the flow and pressure, timer interrupt, fuzzy control adjustment, output control, digital display and keyboard scanning function.Finally, the experimental platform of fire fighting compressed air foam system was set in laboratory conditions. After repeated online debugging and checking, the correctness of system’s hardware and software design were verified, the objectives of compressed air foam proportioning precision and control stability have achieved, and the foundation for further improvement of product modification and engineering use are grounded.