Process and apparatus for drying wet particulate material to a desired moisture content

Claim 1

IN A PROCESS FOR THE DRYING OF WET PARTICLES BEARING SURFACE AND INTERNAL MOISTURE, WHICH PARTICLES, WHEN TRAVELING THROUGH A DRYER PROVIDED WITH AN INLET, AN OUTLET AND HEATING MEANS, RISE IN SURFACE TEMPERATURE DURING A FIRST DRYING PHASE REMAINING AT A SUBSTANTIALLY CONSTANT SURFACE TEMPERATURE DURING A SECOND DRYING PHASE AND AGAIN RISE STILL FURTHER IN SURFACE TEMPERATURE DRYING A THIRD DRYING PHASE, THE LOCATION IN SAID DRYER WHERE SAID SECOND, CONSTANT SURFACE TEMPERATURE PHASE ENDS BEING KNOWN AS TBP, TEMPERATURE BREAKING POINT, SAID TBP BEING APT TO MOVE TOWARDS SAID INLET AND OUTLET AS THE FLOW OF WET PARTICULATE MATERIAL THROUGH THE DRYER FLUCTUATES, THE IMPROVEMENT WHICH COMPRISES: VARYING THE HEAT INPUT TO SAID DRYER IN RESPONSE TO MOVEMENTS OF THE TBP FOR MAINTAINING THE TBP AS CLOSE AS POSSIBLE TO A PREDETERMINED POINT, SAID HEAT INPUT BEING INCREASED IN RESPONSE TO MOVEMENTS OF THE TBP TOWARD THE DRYER OUTLET AND DECREASED IN RESPONSE TO MOVEMENTS OF THE TBP TOWARD THE DRYER INLET, WHEREBY A SUBSTANTIALLY UNIFORM TEMPERATURE GRADIENT MAY BE MAINTAINED IN THE THIRD DRYING PHASE AND A PRODUCT OF CORRESPONDINGLY SUBSTANTIALLY UNIFORM MOISTURE CONTENT MAY BE OBTAINED.