US Patent 7385480 Fire fighting apparatus

An apparatus for fighting a fire comprises a suspendible container having a perforated lower surface each of whose perforations is closed by a heat-sensitive membrane rupturable at an elevated temperature. The container contains a fire retardant material which is released upon rupture of the membrane. The apparatus further includes an electric heater adjacent to the membrane and a smoke detector controlling the heater such that upon the detection of smoke, the heater is switched on to rupture the membrane. A second embodiment has at least one further heat-sensitive membrane embedded in the fire retardant material above the first membrane such that a respective layer of fire retardant material lies above each membrane. Thus, upon rupture of the first membrane, the layer of fire retardant material immediately above it is released and the further membrane comes to rest upon the lower surface of the container, the layer of fire retardant material immediately above the further membrane being released only upon subsequent rupture of the further membrane.