Brown Automatic Signaling Pyrometer

: The Working Of Steel

In large heat-treating plants it has been customary to maintain

an operator at a central pyrometer, and by colored electric lights

at the furnaces, signal whether the temperatures are correct or

not. It is common practice to locate three lights above each

furnace-red, white and green. The red light burns when the temperature

is too low, the white light when the temperature is within certain

limits--for example, 20 deg.F. of the correct temperature--and the

green light when the temperature is too high.

Instruments to operate the lights automatically have been devised and

one made by Brown is shown in Fig. 130. The same form of instrument is

used for this purpose to automatically control furnace temperatures,

and the pointer is depressed at intervals of every 10 sec. on contacts

corresponding to the red, white and green lights.