| 摘要 |
In a process to detect the presence of thickness irregularities in a moving web (30) of e.g. paper, the web passes under a pressure emitter (10) linked to a combined measuring system (20). The combined (10, 20) registers position deflections caused by web thickness variations. Also claimed is a sliding detection assembly mounted on rail and directing an air jet at the moving web (30). The assembly moves with respect to the web. The pressure-adjustable emitter (10) is an air jet, or a mechanical contact, on one side with a suction device on the other. In an alternative embodiment the emitter is a non-contact device e.g. a laser gap-measuring instrument. The distance between detector and web is power-variable. The detector (20) spans the web width and emits an electrical signal in response to a change in web thickness.
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