This invention is composed of the gas generators, fast speed cooling devices and leather pockets. The working principle is that when a submarine has an accident, the solid powder is automatically ignited, the gas is cooled and fills the leather pocket to generate buoyancy, making the submarine floating up. The features of the invention are that: (1) the buoyancy provided is extra and is not constrained; (2) it is separated from the high-pressure system, so that no problem of explosion and burning exists; (3) since its volume is small, it is easy to operate and can be used in any type of submarines. |