| abstract |
A device for detecting combustion products and effects resulting from combustion is made by preparing a composition of metallo-phthalocyanine in amorphous or crystaline form selected from the group of FeIIPc, FeIIIPc, NiIIPc, CuIIPc, CuPc-CCl4 where Pc represents phthalocyanine, mixing the metallo-phthalocyanine in powder form with a carbon-containing solvent and allowing it to remain in the solvent for a period of time to modify its initial phthalocyanine molecule, stirring the mixture to provide a suspension of the modified composition in the solvent, applying a thin uniform coating of such suspension in a selected pattern on an insulating substrate and drying the coating to form a resistance element having a resistance between 106 ohms and 1010 ohms. Electrical contacts are provided for connecting such resistance element into an electrical circuit for measuring its electrical resistance and thereby detecting change of electrical resistance produced by exposure to combustion products and effects resulting from combustion. |