Automatic heater control for a paper drying system

Claim 1

SYSTEM FOR DRYING A CONTINUOUS WET PAPER SHEET, COMPRISING, A DRYING ROLL FOR PRESSURE CONTACTING A SHEET, A HIGH TEMPERATURE HEAT RADIATING SHELL ASSEMBLY DISPOSED IN SPACED RELATIONSHIP PARTIALLY SURROUNDING SAID DRYING ROLL, SAID SHELL ASSEMBLY BEING SHAPED SUBSTANTIALLY CONCENTRICALLY WITH DRYING ROLL, MEANS MOUNTING SAID SHELL ASSEMBLY FOR MOVEMENT TOWARD AND AWAY FROM SAID ROLL TO PERMIT THE REMOVAL OF BROKE FROM THE SPACE BETWEEN SAID SHELL ASSEMBLY AND SAID DRYING ROLL, MEANS FOR CIRCULATING A HEAT TRANSFER FLUID AT TEMPERATURE OF AT LEAST 500* F. THROUGH SAID HEAT RADIATING SHELL ASSEMBLY, MEANS FOR HEATING SAID HEAT TRANSFER FLUID, MEANS FOR HEATING SAID DRYING ROLL, AND A TEMPERATURE CONTROL APPARATUS COMPRISING MEANS FOR RE-CIRCULATING A PORTION OF SAID HEAT TRANSFER FLUID EXITING FROM SAID SHEEL ASSEMBLY BACK INTO SAID SHELL ASSEMBLY, AND CONTROL MEANS FOR CON-