Fire and explosion detection and suppression

Claim 1

A fire and explosion detection system responsive to radiation from fires and explosions and capable of discriminating between a first case in which radiation is produced from a source of fire and explosion in the presence of a flammable substance before it commences to burn and a second case in which radiation is produced therefrom in the absence of the flammable substance, so as to produce an alarm signal in the first case but not in the second case, comprising first and second radiation detection means arranged to produce electrical signals in response to radiation received in respective narrow wavelength bands, the wavelength band of the first radiation detection means being a band in which the said flammable substance absorbs radiation from the said source, and the wavelength band of the second radiation detection means being a band not associated with absorption by the flammable substance of radiation from the said source, and output means comprising means for comparing the electrical signals of the two detection means whereby to produce a said alarm signal indicative of the said first case when the comparison indicates that the signal from the first detection means is relatively low compared with the signal from the second detection means.

Claim 18

A system for protecting a target carrying hydrocarbon fuel against hydrocarbon fires caused by attack by an exploding ammunition round but not against the exploding ammunition round itself, comprising radiation detection means mounted on the target so as to be capable of viewing an exploding ammunition round after it has struck the target, the detection means including a first radiation detector arranged to be responsive to radiation in a narrow wavelength band centered at an intense absorption band characteristic of hydrocarbons and a second radiation detector responsive to the intensity of radiation in a band not associated with absorption of hydrocarbons, each said radiation detector producing a respective electrical signal corresponding to the radiation intensity detected in its respective band, ratio means reponsive to the two said electrical signals to measure the ratio therebetween so as to be capable of distinguishing between the condition when there is relatively lower radiation intensity in the band of the first radiation detector compared with the radiation intensity in the band of the second radiation detector, indicating that the radiation from the exploding ammunition round is being sensed through hydrocarbon vapour before the latter commentces to burn, and the condition when there is relatively higher intensity in the band of the first radiation detector compared with the radiation intensity in the band of the second radiation detector, indicating that the radiation from the exploding ammunition round is being sensed in the absence of such a vapour, the ratio means being operative to produce a warning output in the former condition but not the latter, and means responsive to the warning output to discharge a hydrocarbon fire suppressant or extinguishant.

Claim 19

A system for protecting a target carrying hydrocarbon fuel against hydrocarbon fires caused by attack by an exploding ammunition round but not against the exploding ammunition round itself, comprising radiation detection means mounted on the target so as to be capable of viewing an exploding ammunition round after it has struck the target, the detection means including a first radiation detector arranged to be responsive to radiation in a narrow wavelength band centered at an intense absorption band characteristic of hydrocarbons and a second radiation detector responsive to the intensity of radiation in a band not associated with absorption of hydrocarbons, each said radiation detector producing a respective electrical signal corresponding to the radiation intensity detected in its respective band, ratio means reponsive to the two said electrical signals to measure the ratio therebetween so as to be capable of distinguishing between the condition when there is relatively lower radiation intensity in the band of the first radiation detector compared with the radiation intensity in the band of the second radiation detector, indicating that the radiation from the exploding ammunition round is being sensed through hydrocarbon vapour before the latter commentces to burn, and the condition when there is relatively higher intensity in the band of the first radiation detector compared with the radiation intensity in the band of the second radiation detector, indicating that the radiation from the exploding ammunition round is being sensed in the absence of such a vapour, the ratio means being operative to produce a warning output in the former condition but not the latter, and means responsive to the warning output to discharge a hydrocarbon fire suppressant or extinguishant.