Abstract: To determine the density of a stream of fibrous material on a cigarette manufacturing machine, two different measurements are performed, the first of which is capacitive and supplies a first signal as a function of the density of the dry component and of the density of the liquid in the stream of fibrous material, and the second of which is ultrasonic and supplies a second signal indicating the density of the dry component; the second signal is combined with the first signal to obtain a third signal indicating the density of the liquid in the stream of fibrous material; and, from the third and second signals, a fourth signal is obtained indicating the density of the stream of fibrous material as the sum of the density of the dry component and of the liquid in the stream of fibrous material.

Abstract: To determine the density of a stream of fibrous material on a cigarette manufacturing machine, two different measurements are performed, the first of which is capacitive and supplies a first signal as a function of the density of the dry component and of the density of the liquid in the stream of fibrous material, and the second of which is optical and supplies a second signal indicating the density of the dry component; the second signal is combined with the first signal to obtain a third signal indicating the density of the liquid in the stream of fibrous material; and, from the third and second signals, a fourth signal is obtained indicating the density of the stream of fibrous material as the sum of the density of the dry component and of the liquid in the stream of fibrous material.

Abstract: Cigarettes on a conveyor are surface checked, in at least one observation station, by means of at least one optical unit having a light source for directing light rays on to one half of the outer surface of the cigarette, and a pair of prismatic bodies facing respective quarters of the surface of the cigarette, and which provide for directing all the rays reflected from the aforementioned half of the surface into one beam directed towards one monitoring unit.

Abstract: The apparatus for cutting the string ties of products carried on pallet-like supports has at least one cutting unit with a transverse beam arranged above a line for the conveyance of the pallet-like supports so as to be slideable in a direction which is longitudinal to the conveyance line. The unit is moved at a speed equal to the advancement speed of the pallets. Two trucks are slideably mounted on the transverse beam and support a pair of vertically slideable arms. The arms have a cutting element, for automatically locating the string tie to be cut, and an opposite element for gripping the string tie, which cooperates with the cutting element. Rollers for removing the cut string tie cooperate with the gripping element.