FIELD: packaging industry.
SUBSTANCE: web-like or sheet-like packaging material converted into a tube, sealed at one end, filled with the content, sealed again for placement of the content, which is cut and formed in the package has a plurality of magnetised areas on it, comprising a spot on each package. At that one of the magnetised areas provides the first magnetic label bearing the pattern of the magnetic field power lines, providing information about the position, by which any overtwist of the formed tube can be detected and corrected. At that the pattern of the magnetic field power lines comprises the first maximum of the magnetic field having the first polarity and the second maximum of the magnetic field having the second opposite polarity that enable to detect the position of the formed tube in the longitudinal direction by monitoring the shift of the pattern of the magnetic field power lines, and defining a transverse direction parallel to the imaginary axis of the roller while unwinding of the material web, and a longitudinal direction perpendicular to the transverse direction and the imaginary line between the middle of the first maximum and the second maximum of the pattern of the magnetic field power lines. At that the pattern of the magnetic field power lines is formed so that the angle between the imaginary line and the longitudinal direction is equal to a value between -10 and 10 degrees.
EFFECT: improvement of quality.
10 cl, 2 dwg
