Article: A Guide To Metal Detection In The Food Manufacturing Industry
The most widely-used type of metal detector in the food industry functions on the principle known as the "balanced coil" system. This was first registered as a patent in the 19th century, but the first industrial metal detector was not produced in the UK until 1948.
The progress of technology has taken metal detectors from valves to transistors, to integrated circuits and more recently, into microprocessors. Naturally this has increased their performance giving greater sensitivity, stability and flexibility, as well as widening the range of output signals and information they provide.
All the same, modern metal detectors are still unable to detect every particle of metal passing through them. The physical laws applied in the technology limit the absolute capability of the instrument. Consequently, as with any measuring instrument, metal detectors have restrictions on accuracy. These restrictions vary depending on the application, but the main criterion is the size of the detectable metal particle. Despite this, though, metal detectors perform a valuable and essential role in process quality control.