An impedance bridge for surface temperature measurement

Temperature measurement and control is a basic requirement in many industrial processes. A common problem is the measurement of surface temperatures without contacting the object because it is inaccessible, moving, or because contacting might damage the surface finish. For example, this is the type of problem encountered when it is desired to control the surface temperature of metal molds or rolls in order to reproduce or maintain temperature conditions which are found to give a satisfactory product. The trend toward higher quality and uniformity of processed products results in increasingly closer temperature limits and correspondingly exacting requirements for the temperature-measuring instrument.