Calcining apparatus

Claim 1

CALCINING APPARATUS COMPRISING AN UPRIGHT HOLLOW SHAFT, LIME WITHDRAWAL MEANS NEAR ITS LOWER END, FIRST INLET MEANS NEAR SAID LOWER END, MEANS ADAPTED TO FORM AND TO INTRODUCE A LEAN COOL MIXTURE OF FUEL AND AIR INTO SAID FIRST INLET MEANS TO COOL LIME BY TRANSFERRING HEAT THEREFROM TO WARM THE MIXTURE WITHOUT IMMEDIATE IGNITION, FIRST OUTLET PORT MEANS ABOVE SAID FIRST INLET MEANS, WITHDRAWAL MEANS FOR DRAWING SOME OF THE WARM LEAN MIXTURE FROM SAID FIRST OUTLET PORT MEANS, THE REMAINING WARM LEAN MIXTURE BEING ADAPTED TO IGNITE AT A FIRST HIGHER TEMPERATURE IN THE KILN ABOVE SAID FIRST OUTLET PORT MEANS, SAID FIRST HIGHER TEMPERATURE BEING SUFFICIENT FOR LIME FINISHING, SECOND INLET MEANS ABOVE SAID FIRST OUTLET PORT MEANS FOR THE INTRODUCTION OF A RICH FUEL AND AIR MIXTURE ADAPTED TO IGNITE AT SAID FIRST HIGHER TEMPERATURE TO ESTABLISH A SECOND HIGHER TEMPERATURE FOR CALCINING, A THIRD INLET MEANS ABOVE SAID SECOND INLET MEANS, MEANS CONNECTING SAID WITHDRAWAL MEANS WITH SAID THIRD INLET MEANS FOR INTRODUCING SOME OF SAID WARM LEAN MIXTURE INTO THE SHAFT AND ADAPTED TO IGNITE AT SAID SECOND HIGHER TEMPERATURE AND COMPLETING COMBUSTION AT A THIRD HIGHER TEMPERATURE FOR CALCINING, SECOND OUTLET PORT MEANS ABOVE THE THIRD INLET MEANS FOR THE ABSTRACTION OF SPENT GASES, AND RECIRCULATING MEANS CONNECTED WITH SAID SECOND OUTLET PORT MEANS ADAPTED TO DELIVER SPENT GASES TO THE SECOND INLET MEANS FOR EVEN DISTRIBUTION OF COMBUSTION TO PREVENT OVERHEATING DURING CALCINATION.