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: The liquid atomizer consists essentially of an ultrasonic excitation system coupled with a narrow bending strip of so small thickness that it does not have sufficient inherent stability for linear alignment. In the case of excitation of bending waves with several essentially parallel, closely spaced nodal lines can be generated on the bending strip. Dimensional stability of the bending strip is achieved by at least one mechanical fixing devices and one prestressing device.

Abstract: Apparatus for atomizing liquids which includes an ultrasonic excitation system, a bending resonator which oscillates at ultrasonic frequencies, and an amendment for the delivery of liquid into the velocity nodal region of the bending resonator. The bending resonator has at least one surface which is inclined with respect to the axis of the excitaton system. The bending resonator can be in the form of an elongated narrow strip having a plurality of parallel nodal lines. The length of the excitation system is approximately (2n+1) .lambda./4, wherein n is 0 or an integer.

Abstract: Apparatus for atomizing liquids which includes an ultrasonic excitation system, a bending resonator which oscillates at ultrasonic frequencies, and a device for the delivery of liquid into the velocity nodal region of the bending resonator. The bending resonator has at least one surface which is inclined with respect to the axis of the excitation system. The bending resonator can be in the form of an elongated narrow strip having a plurality of parallel nodal lines. The length of the excitation system is approximately (2n+1) .lambda./4, wherein n is 0 or an integer.