With the rapid economic development of China's social development, more and more high-rise buildings, large-scale petrochemical enterprises continue to emerge, made of foam fire engines and higher requirements. The following brief overview of the structure of foam fire truck.
1. Foam extinguishing mechanism
Foam relative density, good flowability, durability and strong resistance to burning, low thermal conductivity, adhesion great. These physical properties enable it to quickly cover the burning surface, it can be isolated from flammable vapor, air, heat transfer, plus cooling, fire played a role.
2. Foam fire engine, structure and working principle
Foam fire truck chassis and its coat from the part of the special equipment composition. Domestic production of foam fire engine to use more of the two types of vehicle manufacturers to provide General Motors chassis. The special equipment includes power take off, water foam tank, equipment boxes, pumping stations, fire pumps, vacuum pump, foam proportioning equipment and fire guns and so on. Its working principle is: The device will power take power output of the engine chassis and gear-driven by a fire pump, through the fire pump, foam proportioning equipment to water and foam by mixing, and then by fire gun and foam fire extinguishing spray gun. Therefore, the requirements of vehicle chassis must meet certain quality and engine power set. Has developed a national standard, the chassis used according to GB6244-86. Fire general chassis series, types, basic parameters and technical requirements; the national standard used, according to industry standards GA39.5-92 Foam Fire General; Appendix A selection of engine power requirements must meet the specified requirements.
2.1 The power output device
Domestic foam fire engine to use more power take the main way of cars, power take layout can take many forms, and the current medium and heavy foam engine will use more power take place between the main clutch and transmission power take sandwich device (transmission Front) and the shaft power take off (rear derailleur) in two forms. Using sandwich power take out the main engine power transmitted by the transmission pump, driven pump running, you can achieve double-acting function. Currently they use this form.
2.2 Water - foam tank
Water - foam tank foam fire truck is loaded on the primary extinguishing agent container industry development under fire for making a variety of materials can be used, the eighties and nineties to use more glass fiber reinforced polyester material, and now the progressive development of high-quality carbon steel materials and stainless steel.
2.3 Equipment containers
Equipment use more steel frame welded box structure, the deposited aluminum alloy sheet or plate. In recent years, the equipment layout inside the box structure can be divided into four types: fixed split file type, separated by files of each frame is fixed, cannot be adjusted; activities split file type, that is split within the framework of the production of secondary aluminum alloy design patterns aluminum, adjustable interval; sliding drawer, that is produced as a push-pull drawers easily accessible form of equipment, but the production is more complex; rotating frame, the separate files will be made into a small rotary cutting equipment, files, the import of foreign fire engines and more using this form. The new models now made more integrated use of four forms, according to the actual structure, reasonable arrangement.
2.4 Fire Pump
Currently configured foam fire engine fire pump can be divided into three categories: pressure pump (low pressure pump), the single-stage centrifugal pumps, such as BS30, BS60, BS40, R100 (imported), etc.; in the combination of low-pressure fire pumps, multi-polar centrifugal pumps. If 20.10/20.40, 20.10/30.60, 20.10/35.70, KSP1000 (imported), etc.; high- and low-pressure pump, such as NH20.NH30 (import), 40.10/6.30 and so on. Fire pump is equipped with the center and rear of the points.
2.5 Pumping Station
As pumping stations and equipment boxes, multi-rigid frame for the whole welded structure, in addition to be placed outside the fire pump, generally also have the equipment placed in the pump room related to firefighter operations.
Foam proportioning device is to draw air foam fire extinguishing system and foam concentrate delivery of major equipment, which can be mixed in proportion of water and foam, generally 3%, 6%, 9% three mixing ratio. At present the production of foam proportioner of more than 6% foam concentrate mixed mainly mixers are generally divided into PH32, PH48, PH64 three specifications. In recent years the introduction of the production of high and low pressure pumps, low pressure pump to use more air ring pump foam proportioning device, and pump design as one.