Mar04

Metal Detectors VLF Technology

Posted by admin on 03/04/12  ~  Posted in: Metal Detectors India  ~  Send feedback »

VLF Technology

Very low frequency (VLF), also known as induction balance, is probably the most popular detector technology in use today. In a VLF metal detector, there are two distinct coils:

  • Transmitter coil - This is the outer coil loop. Within it is a coil of wire. Electricity is sent along this wire, first in one direction and then in the other, thousands of times each second. The number of times that the current's direction switches each second establishes the frequency of the unit.
  • Receiver coil - This inner coil loop contains another coil of wire. This wire acts as an antenna to pick up and amplify frequencies coming from target objects in the ground.

The current moving through the transmitter coil creates an electromagnetic field, which is like what happens in an electric motor. The polarity of the magnetic field is perpendicular to the coil of wire. Each time the current changes direction, the polarity of the magnetic field changes. This means that if the coil of wire is parallel to the ground, the magnetic field is constantly pushing down into the ground and then pulling back out of it.

As the magnetic field pulses back and forth into the ground, it interacts with any conductive objects it encounters, causing them to generate weak magnetic fields of their own. The polarity of the object's magnetic field is directly opposite the transmitter coil's magnetic field. If the transmitter coil's field is pulsing downward, the object's field is pulsing upward.

The animation above demonstrates VLF technology.

The receiver coil is completely shielded from the magnetic field generated by the transmitter coil. However, it is not shielded from magnetic fields coming from objects in the ground. Therefore, when the receiver coil passes over an object giving off a magnetic field, a small electric current travels through the coil. This current oscillates at the same frequency as the object's magnetic field. The coil amplifies the frequency and sends it to the control box of the metal detector, where sensors analyze the signal.

The metal detector can determine approximately how deep the object is buried based on the strength of the magnetic field it generates. The closer to the surface an object is, the stronger the magnetic field picked up by the receiver coil and the stronger the electric current generated. The farther below the surface, the weaker the field. Beyond a certain depth, the object's field is so weak at the surface that it is undetectable by the receiver coil.

sheiban systems pvt ltd, goa, india. manufacturer and exporter of security metal detectors.

Mar04

Anatomy of a Metal Detector

Posted by admin on 03/04/12  ~  Posted in: Metal Detectors India  ~  Send feedback »

Anatomy of a Metal Detector

A typical metal detector is light-weight and consists of just a few parts:

  1. Stabilizer (optional) - used to keep the unit steady as you sweep it back and forth
  2. Control box - contains the circuitry, controls,speakerbatteries and the microprocessor
  3. Shaft - connects the control box and the coil; often adjustable so you can set it at a comfortable level for your height
  4. Search coil - the part that actually senses the metal; also known as the "search head," "loop" or "antenna"

Most systems also have a jack for connecting headphones, and some have the control box below the shaft and a small display unit above.

Operating a metal detector is simple. Once you turn the unit on, you move slowly over the area you wish to search. In most cases, you sweep the coil (search head) back and forth over the ground in front of you. When you pass it over a target object, an audible signal occurs. More advanced metal detectors provide displays that pinpoint the type of metal it has detected and how deep in the ground the target object is located.

Metal detectors use one of three technologies:

  • Very low frequency (VLF)
  • Pulse induction (PI)
  • Beat-frequency oscillation (BFO)

Sheiban Systems Pvt ltd, Goa, India. Supplier and Exporter of Metal Detectors

Mar04

Sheiban Systems Pvt Ltd. is pioneering in manufacturer of industrial as well as security metal detector used for various types of applications under our strict and stringent quality control systems.

We are newly built company having our tremendous potential in research & development to provide solution for metal contamination.

With help of effecient organized team work which makes us to built confidance in our esteemed patron’s through our quality product, back up after sales service & customer care & relation.

Mar04

Metal Detectors Goa India

Posted by admin on 03/04/12  ~  Posted in: Metal Detector Photos  ~  Send feedback »

Metal Detectors Goa India

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Mar04

 

Mention the words metal detector and you'll get completely different reactions from different people. For instance, some people think of combing a beach in search of coins or buried treasure. Other people think of airport security, or the handheld scanners at a concert or sporting event.

The fact is that all of these scenarios are valid. Metal-detector technology is a huge part of our lives, with a range of uses that spans from leisure to work to safety. The metal detectors in airports, office buildings, schools, government agencies and prisons help ensure that no one is bringing a weapon onto the premises. Consumer-oriented metal detectors provide millions of people around the world with an opportunity to discover hidden treasures (along with lots of junk).

In this article, you'll learn about metal detectors and the various technologies they use. Our focus will be on consumer metal detectors, but most of the information also applies to mounted detection systems, like the ones used in airports, as well as handheld security scanners.

Sheiban Systems Pvt. Ltd., Goa, India - Pioneer in Industrial and Security Metal Detectors

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