The pressure foam proportioning device is mainly composed of a foam liquid pressure storage tank with a capsule and a PHY type pressure proportioning mixer made using the Venturi principle. When the water in the system pipe network flows through the pressure reducing orifice of the proportioning mixer, a pressure difference will be formed before and after the orifice. A part of the water (3% or 6%) at the high pressure enters the tank through the water inlet pipe of the foam tank, squeezes the capsule, and squeezes the foam liquid in the capsule through the liquid outlet pipe of the foam tank to the low pressure of the proportioning mixer to mix with water to form a foam mixed liquid. The formed foam mixed liquid is output to the foam generating equipment (medium, low, high multiple foam generators, foam guns, foam cannons, etc.) to mix with air to generate foam fire extinguishing. A part of the water enters the water cavity of the storage tank through the "water inlet valve" pipeline, squeezes the capsule, and due to the small pressure difference before and after the nozzle, the foam liquid in the capsule is squeezed out through the liquid suction pipe and mixed with water to form a foam mixed liquid flow, and the foam is sprayed out through the air foam generator or other spraying equipment to extinguish the fire. There is a rubber capsule in the storage tank to separate the water from the foam liquid. After each use, the water and foam liquid in the tank cannot be mixed and the performance of the original foam liquid remains unchanged, so it can continue to be used, avoiding the waste of foam liquid.
