Manually Operated Pyrometers
Disappearing Filament Pyrometers
Principle of operation
The first disappearing filament pyrometer was built in 1901 by L. Holborn and F . Kurlbaum (Holborn and Kurlbaum, 1903) . Disappearing filament pyrometers are spectral pyrometers where the brightness of a lamp filament is changed by adjusting the lamp current until the filament disappears against the background of the target, whose temperature is to be measured. In pyrometers of this kind, the eye of the observer is itself the detector . In another seldom applied type of pyrometer the brightness match is achieved by the attenuation ofthe target brightness, using a neutral grey...