Method of heating gas permeable material with a lean gas mixture

Claim 1

A METHOD OF SUCCESSIVELY HEATING ALL PORTIONS OF A MASS OF GRANULAR MATERIAL WITHOUT ADMIXED FUEL TO A PREDETERMINED HIGH TEMPERATURE, SAID MATERIAL CONTAINING SUFFICIENT COMBUSTIBLE COMPONENTS TO SUSTAIN COMBUSTION WITHOUT THE APPLICATION OF EXTERNAL HEAT, SAID METHOD COMPRISING THE STEPS OF FORMING THE MATERIAL INTO A GENERALLY HORIZONTAL LAYER HAVING GAS INTERSTITIAL PERMEABILITY, CAUSING A HOT FLAME TO PENETRATE A SURFACE OF SAID LAYER TO ESTABLISH IN SAID LAYER A BURNING ZONE PORTION INITIALLY POSITIONED ADJACENT SAID SURFACE, SAID BURNING ZONE PORTION COMPRISING SAID MATERIAL HEATED TO SAID HIGH TEMPERATURE, AND SUBSEQUENTLY PASSING A LEAN LOW TEMPERATURE MIXTURE OF FUEL AND AIR UNDER PRESSURE, THE COMBUSTION OF SAID MIXTURE BEING NONSELF-PROPAGATING AT SAID LOW TEMPERATURE, TRANSVERSELY INTO SAID PORTION FOR HEATING SAID MIXTURE AND THEN EFFECTING COMBUSTION THEREOF IN THE PRESENCE OF THE HEATED MATERIAL AND FOR URGING THE PRODUCTS OF COMBUSTION TRANSVERSELY THROUGH THE REMAINING PORTIONS OF SAID LAYER, SAID HIGH TEMPERATURE BEING ABOVE THE TEMPERATURE AT WHICH THE COMBUSTION OF SAID MIXTURE IS INITIATED IN THE PRESENCE OF THE HEATED MATERIAL AND BELOW THE INCIPIENT MELTING POINT OF SAID MATERIAL, SAID COMBUSTION OF SAID MIXTURE EFFECTING MOVEMENT OF SAID BURNING ZONE PORTION PROGRESSIVELY TRANSVERSELY THROUGH THE ENTIRE LAYER FROM SAID SURFACE THEREOF WHILE MAINTAINING THE MATERIAL IN SAID BURNING ZONE PORTION AT SAID HIGH TEMPERATURE AND IN AN OXIDIZING ATMOSPHERE.

Claim 2

A METHOD OF SUCCESSIVELY HEATING ALL PORTIONS OF A MASS OF GRANULAR MATERIAL WITHOUT ADMIXED FUEL TO A PREDETERMINED HIGH TEMPERATURE, SAID MATERIAL CONTAINING SUFFICIENT COMBUSTIBLE COMPONENTS TO SUSTAIN COMBUSTION WITHOUT THE APPLICATION OF EXTERNAL HEAT, SAID METHOD COMPRISING THE STEPS OF FORMING THE MATERIAL INTO A GENERALLY HORIZONTAL LAYER HAVING GAS INTERSTITIAL PERMEABILITY, CAUSING A HOT FLAME TO PENETRATE A SURFACE OF SAID LAYER TO ESTABLISH IN SAID LAYER A BURNING ZONE PORTION INITIALLY POSITIONED ADJACENT SAID SURFACE, SAID BURNING ZONE PORTION COMPRISING SAID MATERIAL HEATED TO SAID HIGH TEMPERATURE, AND SUBSEQUENTLY PASSING A LEAN LOW TEMPERATURE MIXTURE OF FUEL AND AIR UNDER PRESSURE, THE COMBUSTION OF SAID MIXTURE BEING NONSELF-PROPAGATING AT SAID LOW TEMPERATURE, TRANSVERSELY INTO SAID PORTION FOR HEATING SAID MIXTURE AND THEN EFFECTING COMBUSTION THEREOF IN THE PRESENCE OF THE HEATED MATERIAL AND FOR URGING THE PRODUCTS OF COMBUSTION TRANSVERSELY THROUGH THE REMAINING PORTIONS OF SAID LAYER, SAID HIGH TEMPERATURE BEING ABOVE THE TEMPERATURE AT WHICH THE COMBUSTION OF SAID MIXTURE IS INITIATED IN THE PRESENCE OF THE HEATED MATERIAL AND BELOW THE INCIPIENT MELTING POINT OF SAID MATERIAL, SAID COMBUSTION OF SAID MIXTURE EFFECTING MOVEMENT OF SAID BURNING ZONE PORTION PROGRESSIVELY TRANSVERSELY THROUGH THE ENTIRE LAYER FROM SAID SURFACE THEREOF WHILE MAINTAINING THE MATERIAL IN SAID BURNING ZONE PORTION AT SAID HIGH TEMPERATURE AND IN AN OXIDIZING ATMOSPHERE.