Abstract: A device is provided for determining the water content of a target (1), the device having at least one source of target radiation (2), at least one source of reference radiation (4) directed to a target surface (10), and at least one detecting element (3) for measuring the intensity of radiation reflected back by the target surface. During use the at least one source of target radiation (2), the at least one source of reference radiation (4), and the at least one detecting element (3) are arranged immediately opposite the target surface (10). A pressurizing device using air or gas is provided, by which an artificial movement of the air or gas atmosphere can be created in the area of the optical paths between the at least one source of target radiation (2) and the target surface (10), and/or between the at least one source of reference radiation (4) and the target surface (10), and/or between the target surface (10) and the at least one detecting element (3).

Abstract: A device is provided for determining the water content of a target (1), the device having at least one source of target radiation (2), at least one source of reference radiation (4) directed to a target surface (10), and at least one detecting element (3) for measuring the intensity of radiation reflected back by the target surface. During use the at least one source of target radiation (2), the at least one source of reference radiation (4), and the at least one detecting element (3) are arranged immediately opposite the target surface (10). A pressurizing device using air or gas is provided, by which an artificial movement of the air or gas atmosphere can be created in the area of the optical paths between the at least one source of target radiation (2) and the target surface (10), and/or between the at least one source of reference radiation (4) and the target surface (10), and/or between the target surface (10) and the at least one detecting element (3).

Abstract: This invention relates to a method for detecting a tear in a fibrous web in a drying section of a machine for producing the fibrous web, whereby the fibrous web is passed through the drying section by way of at least one dryer fabric, whereby the tear is detected by at least one optical web tear detection device, which includes at least one luminous source and one detector, and whereby a cut-off apparatus for the fibrous web is directly or indirectly activated by the web tear detection device. The optical web tear detection device is operated over an extended wave length range in order to detect a tear in the fibrous web reliably. In addition, the invention relates to an apparatus for performing the inventive method.

Abstract: This invention relates to a method for detecting a tear in a fibrous web in a drying section of a machine for producing the fibrous web, whereby the fibrous web is passed through the drying section by way of at least one dryer fabric, whereby the tear is detected by at least one optical web tear detection device, which includes at least one luminous source and one detector, and whereby a cut-off apparatus for the fibrous web is directly or indirectly activated by the web tear detection device. The optical web tear detection device is operated over an extended wave length range in order to detect a tear in the fibrous web reliably. In addition, the invention relates to an apparatus for performing the inventive method.