Research And Design Of The Foam Fire Extinguishing Control System On Fire Engines

With the extensive application of new chemical materials, the building structures become more complex and intensive, in the event of fire, the loss of lives and property and environmental pollution caused is very serious. While traditional fire fighting methods is getting worse, the newly compressed air foam fire extinguishing system is one of the best fire fighting methods for solids and flammable liquid fire. So it is particularly important significance to study the control system of it.In the background, the foam proportioner and the pressure and flow balance control of the air in the compressed air foam fire extinguishing systems are researched and designed in the thesis. The thesis analyzes the development in the world of the compressed air foam fire extinguishing system, and further makes control system functional requirements analysis, on this basis, it has got the overall control system design, and system hardware and software design. According to the control system functions as well as the main controller’s speed of operation and interface requirements, the thesis selects two main chip PIC18F4682, the one uses to control the foam percentage of mixing, and the other controls the balance of air and a mixture at pressure and flow, at the same time, the two controllers communicate through the UART interface transceivers. The hardware design has power module circuit, buttons and digital display circuit, the signal acquisition circuit and control output circuit; the software design completes the acquisition of the water flow and pressure, the simulation of the serial communication, timer interrupt, fuzzy control adjustment, output control, digital display and keyboard scanning function.Finally, in the laboratory we set up experimental platform of fire fighting foam proportioning control and compressed air’s control, After repeated online debugging and checking of the control system, it verifies the rationality of the system’s hardware and software design. The system designed by us has achieved the objectives of a compressed air foam proportioning’s precision and stability control, and laid the foundation for the improvement of the product and the test on the fire truck.