A coating system for detecting the presence of contaminants carried by a fluid that is applied as a coating on a workpiece. A tube guides the fluid along a flow path to the workpiece. A light source illuminates the fluid along at least a portion of the flow path, and this light is scattered by any contaminants...http://www.google.de/patents/US5509375?utm_source=gb-gplus-sharePatent US5509375 - Apparatus and method for detecting contaminants carried by a fluid
