Patent ID: 7448795

Claim:
A preconditioner, comprising: an elongated mixing vessel having a material inlet and a material outlet and configured to receive a material to be processed including a plurality of different ingredients: apparatus operable to deliver moisture into said mixing vessel during processing of said material; a pair of elongated mixing shafts each having a plurality of elongated, outwardly extending mixing elements, said shafts located in laterally spaced apart relationship within said vessel with the elements of each shaft being intercalated with the elements of the other shaft, said elements oriented to avoid any collision between the elements during rotation of said shafts; a pair of variable drive mechanisms respectively coupled with said shafts in order to permit selective rotation of the shafts at individual rotational speeds independent of each other and to allow high-speed adjustment of said rotational speeds of said shafts without collision between said mixing elements; and a controller operably coupled with said drive mechanisms to independently control the rotational speed of said shafts.