How Do Metal Detection Security Gates Detect Metal Substances?

- May 20, 2019-

How do metal detection security gates detect metal substances?

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We often see metal detection security doors in public places such as stations, museums, cinemas and so on. They are used to check whether our belongings have guns, control knives and so on. What is the principle of the security gate? How did he detect whether there were metal objects?


When we usually pass through the metal detection security gate, if the quantity, weight and shape of the metal exceeds the pre-set parameters, the security gate will immediately alarm and show the location of the metal. The reason why the security gate can detect metal material is that the door panels on both sides of the security machine are equipped with devices that emit and receive alternating electromagnetic fields. It uses the principle of electromagnetic induction: a coil passing through AC generates a rapidly changing magnetic field, which can induce eddy current inside a metal object; eddy current generates magnetic field, which in turn affects the original magnetic field and causes the sounds of the detector. Metal detection security gates are applicable to public security bureaus, procuratorates, prisons, gymnasiums, entertainment venues, railway stations, electronics, wires and cables, electrical appliances manufacturers and so on.