Ingot heating furnace

Claim 1

A FURNACE FOR HEATING ELONGATE METAL BILLETS TO A SUBSTANTIALLY UNIFORM PREDETERMINED TEMPERATURE COMPRISING IN COMBINATION: WALL MEANS FORMING A HEATING CHAMBER FOR THE BILLETS TO BE HEATED, SAID CHAMBER HAVING A FIRST OPENING AND A SECOND OPENING DISPOSED VERTICALLY FROM SAID FIRST OPENING; SUPPORT MEANS DISPOSED GENERALLY HORIZONTALLY WITHIN SAID CHAMBER AND ADJACENT THE BOTTOM THEREOF FOR SUPPORTING A PLURALITY OF BILLETS DISPOSED GENERALLY VERTICALLY WITHIN SAID CHAMBER; DUCT MEANS CONNECTING SAID SECOND OPENING TO SAID FIRST OPENING AND FORMING A GENERALLY CLOSED RECIRCULATING PATH WITH SAID CHAMBER; RECIRCULATING MEANS FOR RECIRCULATING ATMOSPHERE THROUGH THE GENERALLY CLOSED PATH VERTICALLY THROUGH SAID CHAMBER FROM SAID FIRST OPENING TO SAID SECOND OPENING AND THENCE BACK TO SAID FIRST OPENING THROUGH SAID DUCT; FIRST HEATING MEANS IN SAID DUCT MEANS FOR SUPPLYING HEAT TO SAID RECIRCULATING ATMOSPHERE WITHOUT DIRECT RADIATION TO SAID BILLET; A TEMPERATURE CONTROLLER COMPRISING A TEMPERATURE SENSING ELEMENT WITHIN SAID CLOSED PATH AND ADJACENT SAID FIRST OPENING FOR REGULATING THE HEAT INPUT FROM SAID FIRST HEATING MEANS IN RESPONSE TO THE TEMPERATURE SENSED BY THE SENSING MEANS; SECOND HEATING MEANS ADJACENT SAID SECOND OPENING FOR RADIATING HEAT TO SAID BILLETS; AND REGULATING MEANS FOR REGULATING THE RATE AT WHICH HEAT IS RADIATED FROM SAID SECOND HEATING MEANS TO SAID BILLETS INDEPENDENTLY OF THE RATE AT WHICH HEAT IS SUPPLIED BY THE FIRST HEATING MEANS TO THE RECIRCULATING ATMOSPHERE.