Vapor generator with gas recirculation

Claim 1

A VAPOR GENERATOR COMPRISING IN COMBINATION A FURNACE HAVING HEAT EXCHANGE TUBES ON ITS WALL, A GAS PASS EXTENDING FROM THE FURNACE, MEANS FOR HEATING VAPOR HAVING AT LEAST A PORTION THEREOF DISPOSED IN SAID GAS PASS, MEANS FOR FIRING SAID VAPOR GENERATOR WITH A PARTICULATE FUEL OF HIGH MOISTURE CONTENT AND FOR REGULATING THE TEMPERATURE OF THE VAPOR HEATED IN SAID VAPOR HEATING MEANS COMPRISING; A PULVERIZING MEANS, THE EFFLUENT FROM WHICH IS CONVEYED TO THE FURNACE, MEANS SUPPLYING SAID FUEL TO THE PULVERIZING MEANS; MEANS PASSING A HOT GASEOUS MEDIUM THROUGH THE PULVERIZING MEANS FOR FUEL ENTRAINMENT AND DRYING INCLUDING MEANS CONVEYING THERETO HOT GASES FROM THE FURNACE, SEPARATE MEANS CONVEYING THERETO COMBUSTION GASES WHICH HAVE TRAVERSED SAID VAPOR HEATING MEANS, MEANS CONVEYING THERETO AIR; AND MEANS REGULATING THE SUPPLY OF GASEOUS MEDIUM TO THE PULVERIZING MEANS IN RESPONSE TO THE TEMPERATURE OF THE VAPOR LEAVING SAID VAPOR HEATING MEANS AND TO MEET THE TEMPERATURE AND FLOW REQUIREMENTS OF THE MILL.