Production of a Linear Temperature Rise in an Electrical Furnace

Temperature control of an electrical furnace is generally accomplished by means of a servo mechanism. For simple laboratory experiments, however, it may be desirable to control temperature by manual adjustment of power and thus avoid the expense of building a servo. A procedure is offered here for producing a linear temperature rise in an electrical furnace by a time-dependent power function, Q (t). This function is a correspondence of power needed in the heating coil (to produce the desired rate of temperature rise) vs time. A computer analyzes the characteristics of the furnace, calculates the function, and tabulates it. By an iteration of the procedure, the deviation of the temperature-time curve from linearity can be decreased from about 15% to less than 1%