Metal detectors are electronic devices specifically designed for locating metal contaminants present in a general flow of materials. Their main function is to protect industrial equipment (such as crushers, grinders, mills, granulators, etc.) that could be damaged due to contact with metal element.

Depending on their shape, metal detectors can be either tunnel model or mounted above/below a conveyor belt. In the tunnel model, the conveyor belt circulates inside the detector and the magnetic field simultaneously scans both the top and bottom surfaces of the transported material. Alternatively the metal detector can be placed suspended above the conveyor belt or installed under it, depending on the analysis performed by the manufacturer's technical department to obtain an optimal performance in the detection.

Each time a metal contaminant is detected, various actions can be generated, such as stopping the conveyor belt, activating an acoustic and/or luminous alarm signal (flashing lights), activation of baffle to separate the contaminated product and so on.