TEMPERATURE CONTROL BY DIRECT MEASUREMENT OF ELECTRIC FURNACE HEATING ELEMENT RESISTANCE FOR INDUSTRIAL HEAT TREATMENT PROCESSES

摘要

Electric furnace temperature measurement typically uses thermocouple or optical pyrometer thermometry. Implicit in their use is an additional manufacturing and maintenance cost burden which may be overcome if the heating elements themselves are used as the primary temperature transducer.In this paper we discuss the merits and practicalities of using element resistance to accurately infer mean interior brickbox temperature and evaluate the properties of common element materials. Experimental results gained on low and high temperature furnaces are discussed, concluding in a discourse of how element resistance thermometry could be applied to the conventional closed-loop temperature control system.