Abstract: A hydration-expansive crushing cartridge which is prepared by filling a hydration-expansive crushing agent into a container made of a material which allows the permeation or penetration of water and which can be broken by an external force. The cartridge can be charged into holes bored in a concrete structure, a rock bed or the like to crack it regardless of the positioning or the direction of the bored holes and which has a homogeneous crushing capability.

Abstract: A gas generator for instantaneously supplying a gas to an inflatable bag such as a gas bag for protection of a car passenger from injuries in a collision, of the type comprising a solid gas-generating composition confined in a reaction chamber defined in a housing having a perforated wall. The reaction chamber is bounded by a wire screen which is spaced from the perforated wall, and another wire screen is arranged along the inside of the perforated wall. Adequately sized granules of SiC are packed in a space bounded by the two wire screens to efficiently absorb heat and remove solid matter from the generated gas without offering an unduly great resistance to the gas flow. Best cooling and filtering effects can be gained by the use of .alpha.-SiC granules of a sharp-edged particle shape.

Abstract: An automatically inflating lifesaving buoy device having a gas generating device in which the gas generating composition is ignited by an electric ignition device powered by a water-activated electric cell or battery. The gas then generated is cooled as it flows into an inflatable bag to form the lifesaving buoy.

Abstract: A gas generator for an inflatable life raft having a gas-generating chamber filled with a gas-generating composition which generates gas by chemical reaction, either a chemical cooling chamber or a physical cooling-and-filtering chamber or both, a gas passage in communication with a safety valve, and an ignition device which provides rotational friction between a friction means and a frictional igniting agent. The gas generator has the advantages that it is not influenced by the environmental temperature, a gas temperature drop due to adiabatic gas expansion accompanying the gas discharge does not occur and therefore the generated gas can very reliably be discharged, the gas is fully cleaned, troubles due to abnormality of the gas-generating composition can be avoided, and it can be made light and small.