| 摘要 |
<p>The invention discriminates between the explosion of an ammunition round itself and the fire or explosion (e.g. a hydrocarbon fire) which may then take place in the object (e.g.a vehicle) struck by the round and initiates suppression of the latter fire or explosion only. The vehicle carries a radiation detector which measures the ratio of the intensities of the radiation at 3.4 and 4.4 microns. When an exploding ammunition round passes through the fuel tank entraining initially unburning hydrocarbon fuel with it, the detector measures a relatively low ratio because the unburning hydrocarbon fuel vapour between the burning round and the detector has a very intense absorption band at 3.4 microns. Fire suppression is thus initiated, so as to suppress the hydrocarbon fire which would very shortly follow. If the round does not strike the fuel tank, hydrocarbon fuel vapour is not present in the vicinity of the exploding ammunition round and the ratio measured by the detector is higher and explosion suppression is not initiated.</p> |
