Rotary kilns

Claim 1

A ROTARY KILN COMPRISING AN ELONGATED TUBULAR RE-ACTION CHAMBER, MEANS MOUNTING SAID REACTION CHAMBER FOR ROTATION ABOUT ITS LONGITUDINAL AXIS WITH SAID AXIS SLIGHTLY OFFSET FROM HORIZONTAL, AN INGREDIENT FEED MECHA-NISM POSITIONED AT THE HIGHER END OF SAID REACTION CHAM-BER AND COMMUNICATING WITH THE INTERIOR THEREOF FOR SUPPLYING INGREDIENTS THERETO, A HEAT SOURCE POSITIONED IN COMMUNICATION WITH THE INTERIOR OF SAID REACTION CHAMBER AND OPERABLE TO DIRECT HEAT ENERGY AT ELEVATED TEMPERATURES AXIALLY THROUGH SAID INTERIOR TO ELEVATE THE TEMPERATURE OF THE INGREDIENTS THEREIN, AND A TUBULAR OUTER SHELL COMPLETELY SURROUNDING AND EXTENDING OVER THE LENGTH OF SAID REACTION CHAMBER EXCEPT IN THE REGION OF SAID MOUNTING MEANS AND AFFIXED TO SAID REACTION CHAMBER FOR ROTATION THEREWISTH, SAID TUBULAR OUTER SHELL BEING ARRANGED WITH ITS ENDS DISPLACED LONGITUDINALLY AND ISOLATED FROM SAID INGREDIENT FEED MECHANISM AND FROM SAID HEAT SOURCE SO THAT THE ENDS OF SAID TUBULAR OUTER SHELL ARE POSITIONED SUCH THAT THE ANNULAR SPACE DEFINED BY SAID TUBULAR OUTER SHELL AND SAID REACTION CHAMBER COMMUNICATES SOLELY WITH THE OUTER ATMOSPHERE AT THE ENDS OF SAID SHELL, WHEREBY THERE IS MAINTAINED WITHIN SAID ANNULAR SPACE AND OVER THE SURFACE OF SAID REACTION CHAMBER, A HEAT INSULATIVE SPACE WHICH SERVES TO MAINTAIN AN EVEN CONTROL OF TEMPERATURE ABOUT SAID KILN WHILE SUBSTANTIALLY REDUCING HEAT LOSSS THEREFROM.