Continuous non-contact measurement of thickness of organic deposit improving textile or metallic sheet, evaluates near infra red returns at measurement- and reference wavelengths

摘要

The material is illuminated in a measurement region (SF) using NIR light in part (F1) of the waveband 800-4000 nm. Emitted or returned light is filtered for the bandwidth F1. Returns intensity is taken as a measure of deposit mean thickness, or of thickness variation. Results are registered and evaluated in real time. An Independent claim is included for corresponding equipment, including a source (L) and optics (O, B) producing a spot of light of defined shape on the moving material. A returns detector (B, HS, E, A) and evaluation electronics are included. Preferred features: Evaluation includes comparison with a predetermined intensity, or threshold discrimination. The material is illuminated continuously and returns are evaluated continuously. In a second, parallel procedure resembling the first, the material is illuminated by radiation in a second part (F2) of the waveband cited. Returns from this illumination form a reference value used to evaluate returns in the band width F1. First and second partial bands (F1, F2) lie outside absorption bands of the organic component of the layer. The flat material (G) is a fabric with a coating of an organic solvent and/or a textile improvement material. It is a metal foil or a metal band with protective paint or plastic coating. The measurement region is traversed across the direction of travel, from edge to edge. An additional feature of the equipment is the pair of filters covering the partial bands (F1 and F2), which can be driven in alternation into the optical path at the source and/or detector.