Patent ID: 6917895

Claim:
In a method for determination of roll density, in which density of a wound roll formed of a web is determined at a multiplicity of occasions while reeling the web by measuring a parameter corresponding to at least one value selected from the group consisting of: measured web length in the roll (l), measured roll diameter (D), and basis weight of the web (b); and using a known relation between variables: measured web length in the roll (l), measured roll diameter (D), initial roll diameter(D o ), basis weight of web (b) and density (ρ) of the wound roll; l = πρ ⁡ ( D 2 - D 0 2 ) 4 ⁢ b the improvement comprising: eliminating distortions in said measured parameter caused by noise and other disturbances, by using a recursive time variant least squares method in the processing of said measured parameter.