AMORPHOUS METAL TAGGING SYSTEM FOR UNDERGROUND STRUCTURES

摘要

An electromagnetic tagging system (1) is provided for remotely detecting and locating polymeric and other non-conductive structures (2, 6) situated behind barriers (8), such as underground plastic pipes or containers. The system comprises a fluctuating magnetic field source (7), a pattern of tags (10) embedded in discrete regions of the wall of the polymeric structure (2, 6), each tag including an amorphous magnetic metal target for generating a Barkhausen response when exposed to the fluctuating magnetic field source (7, 9) and a portable detection circuit (14, 22) movable along the ground (8) or other control surface for remotely detecting the Barkhausen response (16). The amorphous magnetic material in each tag is preferably in the form of a plurality or elongated particles having aspect ratios of at least 3 to 1 and arranged end-to-end. The pattern (L1, L2) that the tags are arranged in provide information concerning the identity, orientation, or extent of the structure, and the portable detection circuit is capable of detecting at least two of the tags (10) simultaneously as it is moved over the surface of the ground so that the patterns of the tags may be easily determined.