Heat treating apparatus for sheet or web like material

Claim 1

MULTIPLE RUN HEATING APPARATUS FOR WEBS OF SHEET MATERIAL, COMPRISING: (A) WEB GUIDING ROLLERS DISPOSED IN SPACED APART ROWS AND ARRANGED TO FORM A WEB OF SHEET MATERIAL TRAINED ALTERNATELY OVER SUCCESSIVE ROLLERS IN OPPOSITE ONES OF SAID ROWS INTO A PLURALITY OF GENERALLY PARALLEL RUNS; (B) A SERIES OF PARALLEL, SPACED APART RADIANT HEATERS BETWEEN SAID ROWS OF ROLLERS FOR EVOLVING AT LEAST ONE VOLATILE SUBSTANCE FROM SAID WEB WITHOUT IMPARTING SIGNIFICANT HEAT TO THE ATMOSPHERE BETWEEN SAID HEATERS AND SAID WEB, SAID HEATERS BEING PANELS COMPRISED OF TUBULAR CHANNELS HAVING THEREIN A LIQUID HEAT TRANSFER MEDIA WITH A BOILING POINT IN THE RANGE OF FROM ABOUT 500 TO ABOUT 800*F., SAID HEATERS BEING SO LOCATED THAT THE RUNS OF SAID WEB PASS THEREBETWEEN; (C) FLUID CIRCULATING MEANS FOR EFFECTING A FLOW OF FLUID BETWEEN THE RUNS OF THE WEB AND THE RADIANT HEATERS AND GENERALLY PARALLEL TO SAID WEB TO REMOVE FROM ADJACENT SAID WEB THE SUBSTANCES EVOLVED THEREFROM BY SAID RADIANT HEATERS INCLUDING SUPPLY AND EXHAUST DUCT MEANS; (D) MEANS ESTABLISHING FLUID COMMUNICATION BETWEEN SAID SUPPLY AND EXHAUST DUCT MEANS, WHEREBY SAID FLUID MAY BE RECIRCULATED THROUGH SAID HEATING APPARATUS; (E) MEANS FOR CONTROLLING THE PROPORTION OF EVOLVED SUBSTANCES IN THE RECIRCULATED FLUID INCLUDING MEANS FOR DISCHARGING A SELECTIVELY VARIABLE PROPORTION OF THE FLUID FLOWING IN SAID EXHAUST DUCT MEANS THEREFROM AND MEANS FOR ADMITTING FLUID WHICH IS RELATIVELY FREE FROM SAID SUBSTANCES AT A SELECTIVELY VARIABLE RATE TO SAID SUPPLY DUCT MEANS; AND (F) MEANS INDEPENDENT OF THE OPERATION OF SAID RADIANT HEATERS FOR CONTROLLING THE TEMPERATURE OF SAID FLUID INCLUDING AT LEAST ONE HEATING UNIT FOR RAISING THE TEMPERATURE OF THE FLUID AS IT FLOWS THROUGH SAID DUCT MEANS, SAID HEATING UNIT SUPPLYING THE MAJOR PORTION OF THE HEAT ADDED TO SAID FLUID.