Electrical resistance heating apparatus

Claim 1

IN A SYSTEM FOR REGULATING THE AMOUNT OF ELECTRICAL ENERGY TRANSFERRED TO A LOAD TO BE HEATED BY THE ENERGY, THE COMBINATION OF: A STEP-DOWN TRANSFORMER HAVING A PRIMARY WINDING AND A SECONDARY WINDING; SATURABLE REACTOR MEANS HAVING A CONTROL WINDING FOR REGULATING THE LEVEL OF SATURATION AND AT LEAST ONE OUTPUT WINDING FOR PASSING ELECTRICAL ENERGY AS A FUNCTION OF THE SPECIFIC SATURATION LEVEL OF SAID REACTOR MEANS; MEANS, INCLUDING SAID OUTPUT WINDING OF THE SATURABLE REACTOR MEANS, FOR PASSING A.C. ENERGY TO THE PRIMARY WINDING OF THE TRANSFORMER; CONDUCTOR MEANS FOR PASSING ELECTRICAL ENERGY FROM THE SECONDARY WINDING OF THE TRANSFORMER TO THE LOAD; SENSING MEANS DISPOSED ADJACENT SAID LOAD FOR SENSING THE TEMPERATURE THEREOF AND FOR PRODUCING A SIGNAL VOLTAGE RELATED TO THE TEMPERATURE OF SAID LOAD; INDICATING MEANS COUPLED TO SAID SENSING MEANS FOR PROVIDING A VISUAL INDICATION OF THE LOAD TEMPERATURE; POWER SUPPLY MEANS FOR RECEIVING A.C. ENERGY, RECTIFYING THE A.C. ENERGY IN PROPORTION TO A DIFFERENCE SIGNAL, AND PASSING THE RESULTANT D.C. ENERGY TO SAID CONTROL WINDING OF THE SATURABLE REACTOR MEANS; AND COMPARATOR MEANS, COUPLED TO SAID SENSING MEANS, FOR RECEIVING SAID SIGNAL VOLTAGE INDICATING THE TEMPERATURE OF SAID LOAD, AND HAVING AN OUTPUT CIRCUIT CONNECTED TO APPLY SAID DIFFERENCE SIGNAL TO SAID POWER SUPPLY AND THUS REGULATE THE SATURATION LEVEL OF THE SATURABLE REACTOR MEANS, SAID COMPARATOR MEANS INCLUDING ADJUSTING MEANS FOR ESTABLISHING A REFERENCE VOLTAGE FOR COMPARISON WITH SAID SIGNAL VOLTAGE TO PROVIDE SAID DIFFERENCE SIGNAL, TO GOVERN THE DESIRED SATURATION LEVEL OF THE SATURABLE REACTOR MEANS AND THEREBY CONTROL THE TEMPERATURE OF THE LOAD.