Industrial metal detectors indicate the presence of metal in nonconductive materials such as textiles, rubber, oils or liquids, plastics, powders, wood products, ceramics and glasses, and concrete. They are used to determine cleanliness or verify the absence of tramp metal in continuous or bulk products, as well as recycled materials. Applications include the detection of metal chips in pharmaceutical powders or preparations, nails or staples in wood, metal caps in crushed glass, and needles in fabric sheets. Industrial metal detectors are also used to verify the presence and location of metal such as buried electrical lines, piping behind walls, or reinforcing metal rebar in concrete. Airport metal detectors are used to detect guns, knives, bombs, and other weapons. Industrial metal detectors for security applications can also be used to detect metallic items that an individual is trying to smuggle into or out of a secure facility.
Types of Industrial Metal Detectors
Portable Industrial Metal Detectors
There are many different types of industrial metal detectors. A portable or hand held metal detector is suitable for residential, commercial, or on-site use. Vehicle-mounted metal detectors are also commonly available. While they are not technically portable metal detectors, they are fixed in place; the entire device can to be moved to a field or site where detection technology is needed.
Fixed or Inline Metal Detectors
Modular metal detectors can be mounted under a conveyor, on a doorway, or in another area where detection of metal objects is required. Devices are not free-standing and may or may not include a mounting kit. Walk-through metal detectors are most often used in security applications. They detect metals carried though a doorway or passage. Metal detector conveyor systems detect trace amounts of metal where the media is introduced via conveyor or through a pipeline. Others detect metal in gravity-fed or free-flowing media. Industrial metal detectors differ in terms of capabilities, performance specifications, and optional features. A hot metal detector (HMD) can detect metals with temperatures that exceed the cure point. Non-ferrous metal detectors can detect aluminum, brass, and lead. Non-magnetic metal detectors are used to detect alloyed steels and other metals that are classified as non-magnetic. Sensitivity, sensing width or diameter, throughput or mass flow, speed or velocity, and interface type are important specifications to consider. Features for industrial metal detectors include background correction or product-effect compensation, location mapping or marking, product or material rejection, sorting gates, programmability, sensitivity adjustment, and shallow-depth sensing. Devices with a contact-sensitive, touch-screen interface are also available.