| 摘要 |
A fire detector (6) for use in a fire protection system comprises a tube (34) of heat-conductive material extending through a zone to be protected by the system. The tube (34) houses a temperature- responsive element (36) comprising a length of gas-evolving substance, operative when a predetermined critical temperature is reached at any point along the length of the tube, to generate explosively a volume of gas for pneumatically activating a fire extinguisher. The length of gas evolving substance is within a wire mesh sheath (38) which acts as a filter to retain combustion products and unburnt residue from the substance after activation. The sheath (38) avoids the need for thorough cleaning of the system when recommissioning after activation and also facilitates the insertion of a fresh element (36) into the system by means of threaded couplings (40a, 40b) at each end of the sheath. <IMAGE> |
