(A) Product description ??? is the main means for injecting low expansion foam fire extinguishing systems on liquid. Low expansion foam generator is a mixture of air mixed with the inhalation of the proportioning device produced produce air bubbles or foam nozzle shroud through the foam sprayed into the combustion surface to form a foam layer, using foam interdiction, cooling and achieve the purpose of stifling effect fire. (B) the relationship between the use of pressure flow is calculated as follows: generator inlet pressure range is 0.3-0.6 MPa, at different inlet pressure mixture flow is different, so according to the following formula to calculate the specific use of inlet pressure mixture flow: namely Q = K ?????????????? Where: Q: mixture flow (L / min) K: Coefficients P: inlet pressure (MPa)