Measuring the Temperature of Flowing Gases in Furnace Systems. A Comparison between the Ordinary Thermocouple and Suction Pyrometers

JSGT 1932 V16 T315-T326

The errors to which ordinary thermocouple measurements are liable, particularly those made with base metal couples of large diameter, are indicated, and the development of the suction pyrometer as a means of overcoming them is described. Some results of comparisons of the two methods using experimental suction pyrometers are given, and it is shown that the errors of the ordinary thermocouple are most marked when regenerator temperatures are being measured. The errors in some cases may amount to more than 100°. The ordinary suction pyrometer, consisting of a thermocouple the tip of which is centrally placed in a quartz tube through which the gas is sucked, is shown to be an instrument of considerable robustness and accuracy. The Schmidt pyrometer calls for greater manipulative skill, and in the simple form tried was not entirely a success. Data are given to show that the divergence of the temperature recorded by the ordinary thermocouple from that given by the suction pyrometer increases with the diameter o£ the thermocouple wire.

M. Parkin & F. Winks