Apparatus for expelling moisture from tobacco or the like

摘要

Apparatus for expelling moisture from a continuous stream of tobacco which passes through a conditioning zone defined by a hollow rotary drum-shaped dryer has a control unit employing a computer whose output signal is indicative of the quantity of moisture to be expelled from tobacco per unit of time during travel through the dryer in order to ensure that the final moisture content of tobacco will match a predetermined value. The signal which is generated by the computer is used to regulate a valve in a conduit connecting the conditioning zone with a source of steam. The rate of steam admission or the pressure of admitted steam increases when the quantity of moisture which is contained in tobacco entering the dryer per unit of time decreases and vice versa. This ensures that the total quantity of moisture in the conditioning zone remains at least substantially constant even though the moisture content and/or the quantity of tobacco in the stream entering the dryer varies within a wide range. The wall or walls of the dryer can be indirectly heated by steam. A threshold circuit can be installed between the adjusting device for the steam valve and the output of the computer if the conditioning zone is to receive steam only when the initial moisture content of tobacco or the quantity of tobacco which is admitted into the conditioning zone per unit of time is so low that the wall or walls of the dryer would expel excessive quantities of moisture therefrom.