Magnetic field producing apparatus

摘要

Metal detectors having parallel magnetic fields produce signals which vary depending upon the shape and orientation of a metal object passing through the field. An improved metal detector sensor includes a magnet of special configuration having a multi-directional magnetic field resulting in a detector which is insensitive to orientation of the detected metal. One embodiment of the magnet is a pattern of cylindrical poles with the opposing pole central to the cylinder, thus creating a multiplicity of radially extending magnet fields. An alternate embodiment of the invention is an offset pattern of opposite poles which create two groups of fields, each at an angle to the general direction of movement of the material fed into the machine.