Gas heated rotary drier

Claim 1

A rotary drier for particulate or loose material comprising a cylinder arranged to rotate about its axis inclinded to the horizontal, said cylinder having formed along its cylindrical surface a plurality of hollow paddles extending axially along said cylinder and inwardly thereof, the interior of said paddles communicating with the exterior of the cylinder, at least one gas burner arranged below the cylinder to direct flame into the interior of the hollow paddles, said cylinder being surrounded along its length by a cylindrical wall defining a combustion space between said cylinder adn said wall communicating with the interior of said paddles and the bottom therof being open to said burner, the top of the combustion space including a tapered flue gas collection manifold which communicates with a flue duct for removing waste combustion gases, means for introducing air into said cylinder, said means comprising a passageway for conducting ambient air around said cylinder to preheat the air and for separating the ambient air from combustion gases, a fan for drawing air theough said passageway and ducting for the preheated air to the interior of said cylinder, an inlet probe for introducing preheated air into said cylinder at a position intermediate its ends, and means for measuring and controlling the temperature of tobacco within said cylinder.