Radiation detector for a flame alarm

Abstract

Abstract A radiation detector containing as the radiation sensor a pyroelectrical element, for instance, lithium-tantalate or lead-zircanate-titanante. Arranged forwardly of the sensor element is a filter combination composed of a quartz filter element having a vapor-deposited narrow band filter layer with a throughpass maxima at about 4.3 mu m and a germanium filter element. This filter combination displays a sharp throughpass maxima at the resonance radiation of carbon dioxide at 4.3 mu m, whereas all other wavelength ranges greater by the factor 100 or 1000, respectively, are damped. A flame detector equipped with such radiation detector responds extremely selectively to flame radiation, however does not respond to spurious radiation, such as solar radiation or daylight, artificial light sources and welding sparks, even if such have more than a thousand-fold intensity, so that flames of the slightest intensity will be detected positively, sensitively, and free of disturbance even in the presence of pronounced spurious radiation.

Inventors

• 👤 Domokis Tar

Bibliographic Details