All raw material received for processing in the plants comes from refrigeration processes and refrigerated machines, and many times foreign bodies are incorporated into it by accident or some machine components failure. These metallic bodies, being carbon steel or stainless steel, can damage equipment causing serious breakages. To solve this serious problem, an equipment called metal detectors is incorporated into the line, which automatically discards them when detecting their presence. These detectors are installed free standing in vertical ducts or then on conveyor belts.