METAL DETECTORS AND METHODS FOR MAKING THE SAME

摘要

A detector for detecting the presence of metallic objects in, for example, packaged products comprises a housing (1) of non-conductive material which is lined internally with sheets or foil of a suitable conductive material such as aluminium. A tubular non-conductive frame assembly (3) is positioned within the housing and is secured to the front and rear walls of the housing with its sides spaced from the respective sides of the housing. The frame assembly includes an aperture (2) through which packaged products to be inspected can pass. Balanced transmitting and receiving coils are carried about the circumference of the frame assembly and operate to produce within the aperture an electromagnetic field which is disturbed by a metallic object passing through the aperture in a packaged product.