FIELD: physics.
SUBSTANCE: web is placed between acoustically transparent plates of an air capacitor, while gradually increasing the stack and determining its mass. The value of acoustic signal and impedance of the capacitor at the given frequency are determined in accordance with its mass. A curve of capacitor impedance versus the mass of the stack between plates of the capacitor and a curve of the value of the acoustic signal versus the number of fibres in the sounding direction are plotted. The test set of fibres is combed with output on a drum. The required number of layers is placed onto the drum. A multi-layer beam is cut across the combing direction, thereby obtaining a multilayer rectangular stack. The obtained stack is placed between the capacitor plates. Sounding is carried out in the required number of points. The average value of the acoustic signal is found. Impedance of the capacitor with the test fibre is determined. The average number of fibres in the sounding direction and mass of the sample are determined from the obtained curves. The average linear density of the compact set of fibres is then controlled using the obtained data.
EFFECT: high accuracy of controlling the average linear density of a compact set of fibres.
2 cl, 2 dwg
