Light foam generator
A light foam generator (also light foam device) is used to generate light foam as an extinguishing agent for the fire brigade to fight fires . The device consists of a fan similar to an overpressure ventilator, a water inlet and a duct with which the lightweight foam can be distributed. Recently there has also been a variant in which only the air from the fan is pressed through the duct, the device for foam generation is only located at the end of this line (sieve and connection foam compound-water mixture).
Because of the extremely high expansion ratio of high expansion foam is no longer in leaves heavy and medium expansion foam tubes used injector perform, rather, to a special unit, the so-called "high-expansion foam generator", is required.
Mode of action
A commercially available proportioner , which is generally connected to a device, is used to produce a water / foam compound mixture and then feed it to a nozzle system. The nozzles spray the mixture onto a coarse-meshed screen fabric, which can also be braced in a zigzag to increase its surface area. Due to their low surface tension, the liquid droplets hitting the tissue form fine skins between the meshes of the tissue, but these are immediately detached in the form of foam bubbles by a powerful air flow directed against the tissue. The process corresponds exactly to the principle of the well-known children's toy consisting of a small stemmed ring, with which soap bubbles can be generated by counter-blowing after wetting with soap solution.
With the high-expansion foam generator, the air flow is generated by a motor-driven fan . The air flow pushes the foam through large hoses, so-called ducts, with a diameter of 700 to 2,500 mm to the point of consumption. The range of lightweight foam generators of various types and sizes is currently so extensive that only a general overview can be given here. The specified foaming figures are 1,000, more rarely 500 or 333. Various generators can also be switched from VZ 1,000 to 500 or 333 (using an additional device). The flow rates range from 50 to 100, 180, 200, 400, 450 to 600 l / min and can also be varied for individual devices. An electric motor , a gasoline engine , a diesel engine and, in rare cases, a water engine are often used as drive units for the blower (fan) . High-expansion foam generators are supplied as portable, mobile carts, mounted on trailers or as stationary devices.
See also
Individual evidence
- ↑ High expansion foam generator. Weilburg volunteer fire department , accessed on October 11, 2019 .