SETT FOR KONTAKTFRI OCH MATERIALOBEROENDE TEMPERATURMETNING OCH/ELLER -REGLERING PA YTOR MEDELST INFRAROD-PYROMETRI

摘要

Apparatus for measuring the temperature at the surface of thin elongated objects such as a metallic wire by measurement of the infrared radiation emitted from the surface of the object comprises a variably heated metallic compensating radiator provided with an opening through which the object passes and a rotatable chopper wheel interposed between the object surface and the compensating radiator. The side of the chopper wheel facing towards the compensating radiator is made radiation reflective and a radiation detector is positioned to receive in alternation the infrared radiation emitted from the surface of the object and which passes intermittently through the rotating chopper wheel and infrared radiation emitted by the compensating radiator and which is reflected intermittently into the detector from the reflective side of the chopper wheel. The detector produces at its output an alternating current signal determined by any temperature differential existing between the object and compensating radiator, and the heat supply to the compensating radiator is varied in accordance with the signal in such sense as to reduce the signal to zero whereby the temperature of the compensating radiator then equals the temperature of the object.