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Technology Behind Security Metal Detectors


A metal detector is used to detect the presence of metal inside an object and is nowadays largely used for security purposes. When installed in airports, railways stations and other public places, these detectors help the security personnel prevent illegal transportation of valuable metals and metal products along with providing security to people from the whims of potential miscreants. Though the history of metal detector dates back to the late 19th century it was only in the later part of the 20th century that it gained importance in the commercial sector. Nowadays security metal detectors mainly work on the basis of three technologies? the Very Low Frequency technology, the Pulse Induction technology and the Beat Frequency Oscillation technology. All these technologies are competent enough to detect the presence of even a very small metallic body inside an object.

Technology Behind Security Metal Detectors

Very Low Frequency technology

The Very Low Frequency or VLF technology is generally used by those detectors that are assigned to search for metallic bodies in the ground such as mines and hidden treasures. Detectors using this technology have two distinct coils? one for transmitting frequencies and another one to capture and read the reflection. This technology is perfect when there is a requirement of determining the type of metal that has been detected. For this purpose these metal detectors use a special phenomenon called the phase shifting. It calculates the difference in time between the transmission and reception of the frequencies as different types of metals tend to perform differently.

Pulse Induction Technology

Security metal detectors that use the Pulse Induction or PI technology generally have a coil that acts both as the transmitter as well as the receiver of the frequencies. In more powerful detectors two or three coils are simultaneously placed in order to increase the efficiency of the machine. Short bursts of current are generated through the coils who also receive the reflected frequency in order to determine the presence of a metal body. A metal detector using this technology generally generates about 100 pulses per second, though the number varies from one product to another.

BFO technology

The Beat Frequency Oscillator technology is the basic technology that is used by metal detectors. In this technology a small coil is placed inside the control box and a larger coil is placed inside the search head. The coils are connected to an oscillator that shoots a large number of current pulses every second. These equipments are very low cost products, though their performance may fall short of expectation as the technology is not as sophisticated as the other two.

Buying security metal detectors requires a good knowledge about the products and so users have to be extra careful regarding the purchase of these products. It is quite obvious that those who invest their money in these products would definitely not tend to compromise with the quality of the products. One of the most reliable ways to obtain quality products is through online shopping. Buyers just need to go through the online catalogues and place an order according to their requirement. We recommend checking out Protective Technologies International.

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