Magnetic marking system for articles - has strip markings that pass through AC field to generate detector output

摘要

An article (1) has identification markings in the form of bondd thein strips or wires (2) and is fed on a conveyor belt (4) through a detection and identification stator. The article passes through a first stage (9a) that is in the form of a excitation coil coupled to an oscillator (6a). A second exciter stage (9b) is set at right angles and is coupled to a separate oscillator (6b). Detector coils (10a,10b) are set above and below the belt and are coupled together. Outputs are fed to the measuring instrument (8). The outputs generated by the interaction of the markings with the field allows the article to be identified. ADVANTAGE - Allows both presence and type of article to be determined.