Pyrometric measurement procedure and multi-channel pyrometer

Claim 1

A pyrometric measuring method for determining the temperature T o of surfaces with different emissivities ε ij at j=1 to n effective wavelengths by the measurement of the spectral signal voltages U j in j=1 to n spectral channels at a known ambient temperature T u and by means of a functional relationship between the signal voltage difference U oj -U uj and the object temperature of a black-body radiator, said relationship being measured in a calibration process, comprising measuring at a known surface temperature T o the respective signal voltages U ij in the j=1 to n spectral channels for i=1 to m user-specific surface materials i differing in emissivity, wherein n and m are integers and, using the functional relationship between the difference U oj -U uj and the object temperature that is calibrated on a black-body radiator, determining the associated signal voltage differences U oj -U uj and calculating the respective emissivities ε ij for the user-specific i=1 to m surface materials according to the equation ##EQU3## and storing them, measuring, in a measurement step on the unknown surface material i and at an unknown surface temperature T o , the spectral signal voltage U j in the j=1 to n spectral channels, determining for each spectral signal voltage U j obtained in the measurement step, the signal voltage differences U oij -U uj at the calibrated surface materials i according to the equation U.sub.oij -U.sub.uj =U.sub.j /ε.sub.ij using the stored emissivity ε ij , determining with the help of the functional relationship between the surface temperature T o and the difference U oj -U uj in the respective spectral channel j as calibrated at the black-body radiator, the associated object temperatures T oij for each material i, using the previously determined differences U oij -U uj for the differences U oj -U uj obtained at the black-body radiator, and determining the scatter of the object temperatures T oij for each material i in the j=1 to n spectral channels, the average value of the n object temperatures T oij , which have the least scatter for a material i, corresponding to the true object temperature T o .