Evaluation of a horizontal furnace for precise comparison between a radiation thermometer and a platinum resistance thermometer

This paper reports the recent development of a horizontal comparison furnace aimed for the comparison measurement between a standard radiation thermometer and a platinum resistance thermometer. The furnace is placed in horizontal orientation, and a graphite block is placed in the center as a comparison block. One end of the comparison block is the blackbody for the radiation thermometer, while from the other end a platinum resistance thermometer is inserted to measure the temperature of the block. The furnace temperature is controlled with a precise temperature control system yielding a temperature stability of plusmn2 mK at 800degC during a 24 hour period. Measurement results aimed for the evaluation of some of the uncertainty components in the comparison measurement using this furnace is reported in this paper.