System monitoring top layer of object includes transponder screened from transceiver by ferromagnetic layer, to give dependable indication when e.g. conveyor belt, tire or drive belt has undergone defined depth of wear

摘要

In the top thickness (8) a ferromagnetic layer of high permeability (16) is embedded between transponder (6) and top surface (14). This screens the transceiver (4), so that no data is received from the transponder. An Independent claim is included for the monitoring method, also for the object, especially a conveyor belt with top layer subjected to wear, as described. Preferred features: The transponder may lie between the ferromagnetic layer and the reception region. The ferromagnetic layer is parallel to the top layer and comprises a metal foil or wire grid. It is 0.1-2 mm thick. The object or belt is multilayered, the transponder being outside the top layer. The transponder works with an embedded inductance underneath the ferromagnetic layer. Several high permeability layers are embedded, in correspondence with transponder(s). Each transponder relays one characteristic to the receiver.