Patent ID: 7832411

Claim:
A cigarette manufacturing method comprising the steps of: feeding a shredded tobacco stream ( 4 ), on a cigarette manufacturing machine ( 1 ), in a given flow direction ( 11 ) and along a channel ( 2 ) extending through at least one carding unit ( 49 ), comprising at least one output portion ( 51 ) closed by a suction conveyor belt ( 7 ) to form a mat ( 6 ) of tobacco on said suction conveyor belt ( 7 ), and comprising a hopper ( 42 ) connected to said output portion ( 51 ) via said carding unit ( 49 ); and cleaning, upstream from said output portion ( 51 ) and upstream from said carding unit ( 49 ) in said flow direction ( 11 ), said shredded tobacco stream ( 4 ) to remove from the shredded tobacco stream ( 4 ) any relatively heavy parts, such as lumps of tobacco and/or woody tobacco parts and/or foreign bodies; wherein the step of cleaning is performed by feeding the shredded tobacco stream ( 4 ) into a vertical cleaning tower ( 13 ) defined at the bottom by a basin ( 54 ) in which the relatively heavy parts are collected, and at the top by a rotary suction cage ( 52 ) rotating about a horizontal axis ( 53 ) for feeding the shredded tobacco stream ( 4 ) to the hopper ( 42 ) which is located beneath the suction cage ( 52 ) and alongside the cleaning tower ( 13 ).