Patent ID: 7986410

Claim:
A method for detecting a tear in a web of fibrous material in a drying section of a machine for producing the web, the web being passed through the drying section using at least one dryer fabric, said method comprising the steps of: detecting the tear by at least one optical web tear detection device, which includes at least one luminous source and one detector; operating said at least one optical web tear detection device over an extended wave length range to detect the tear in the web reliably, said at least one optical web tear detection device being operated in a full wave length range which is from 200 to 1,100 nm; measuring, with said detector and in said full wave length range, a reflected light; and activating, one of directly and indirectly, a cut-off apparatus for the web by said at least one optical web tear detection device dependent on said step of measuring with said detector in said full wave length range.