Means and method for automatic zone refining a work piece

Claim 1

IN INDUCTION HEATING APPARATUS FOR TREATING A RODLIKE SPECIMEN OF CONDUCTING MATERIAL, WHEREIN ENERGY IS FURNISHED BY AN RF GENERATOR TO AN INDUCTION HEATING WORK TANK CIRCUIT INCLUDING A CAPACITANCE IN PARALLEL RESONANCE WITH AN INDUCTANCE COILED ABOUT SAID SPECIMEN, THE COMBINATION COMPRISING, MEANS FOR MOVING SAID INDUCTANCE COIL ALONG SAID SPECIMEN FOR INDUCING CURRENT FLOW IN SAID SPECIMEN FOR HEATING SAID SPECIMEN WHEREBY SECTIONS OF SAID SPECIMEN SUCCESSIVELY OVERLAPPED BY SAID COIL CONVERT TO A MOLTEN STATE, SAID RF GENERATOR HAVING A RESONANT TANK CIRCUIT DEFINED BY PARALLEL CONNECTED CAPACITOR AND COIL INDUCTANCE ELEMENTS OSCILLATING AT A FREQUENCY DIFFERENT FROM THE FREQUENCY OF THE WORK TANK CIRCUIT, ONE OF SAID ELEMENTS BEING ADJUSTABLY VARIABLE, OPERATOR MEANS FOR REGULATING THE VARIABLE ONE OF SAID OSCILLATOR ELEMENTS, A FIRST CIRCUIT PROVIDING A VOLTAGE CORRESPONDING TO THE SETTING OF THE VARIABLE ONE OF SAID OSCILLATOR ELEMENTS, WHILE THE INDUCTANCE COIL, IN MOVING ALONG SAID SPECIMEN, CONVERTS SUCCESSIVE SECTIONS THEREOF TO THE MOLTEN STATE, A SECOND CIRCUIT PROVIDING A REFERENCE VOLTAGE, MEANS FOR MATCHING SAID VOLTAGES AND PROVIDING A REGULATING SIGNAL IN RESPONSE TO THE UNBALANCE OF SAID VOLTAGES, MEANS FOR CONTROLLING THE GEOMETRY OF SAID SPECIMEN IN RESPONSE TO SAID REGULATING SIGNAL, AND MEANS EFFECTIVE WHILE THE INDUCTANCE COIL, IN MOVING ALONG SAID SPECIMEN, CONVERTS SUCCESSIVE SECTIONS THEREOF TO THE MOLTEN STATE, FOR SENSING THE RF VOLTAGE ACROSS SAID WORK TANK CIRCUIT AND FOR REGULATING SAID OPERATOR MEANS AS A FUNCTION OF THE GAUGED RF VOLTAGE, WHEREBY SAID VARIABLE OSCILLATOR ELEMENT SETTING IS ADJUSTED WHILE THE INDUCTANCE COIL, IN MOVING ALONG SAID SPECIMEN, CONVERTS SUCCESSIVE SECTIONS THEREOF TO THE MOLTEN STATE.