Alcan International Limited

Karam Kang

Matthew J Fairlie

Dan Evans

Serge Zouikin

An apparatus and method for remotely measuring emissivity and hence temperature of a surface of an object. The apparatus includes a detector having a radiation receptor for measuring infra-red radiation, an integrating cavity surrounding the receptor for receiving radiation from a surface facing the cavity and delivering the radiation to the receptor, at least two sources of infra-red containing radiation (e.g. light from an incandescent lamp) within the integrating cavity positioned to produce separate beams of the radiation which strike the surface at different angles suitable for reflection to the receptor, and a processor for determining the temperature of the surface from the radiation measured by the detecting means. The use of at least two mutually angled radiation beams compensates for surface anisotropy of the surface whose temperature is to be measured. The infra-red containing radiation is modulated to cause an on/off fluctuation of the intensity of the radiation so that the component of the signal from the detector resulting from reflected radiation can be distinguished from the component due to radiation emitted from the surface due to its temperature. The radiation is preferably measured at two different wavelengths so that a ratio technique may be employed. The resulting measurements can be used to determine the reflectivity, and hence the emissivity, of the surface as well as the intensity of emitted radiation, so that accurate temperature measurements can be made from standard formulae used for optical pyrometry.

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Kingston, Canada

Karam Kang