How Metal Detectors Work

 

If you have visited a beach, you must have seen someone searching for coins buried underground using a metal detector. These devices can detect hidden metals underground, especially coins.

Recently, the use of metal detectors has increased in public airports, sports matches, as well as metro and train stations for the security safety of passengers, but how metal detectors work?

Metal detectors

Before talking about how metal detectors work, we must know what metal detectors are.

A metal detector can be defined as a device designed to detect metals and various metallic objects under the surface of the earth and other nearby places. These devices rely on a physical rule known as electromagnetic induction.

Metal detectors create a magnetic field, and when there is any metal object, disturbances occur in this field in order for it to be detected by the device. This technology is very common in many different security and military agencies, so it's important to know ho metal detectors work. This device contains two coils, one for transmitting the magnetic field and the other for receiving.

An electric current pass through the transmitter coil that generates a magnetic field, and when this field passes over metals, disturbances in the magnetic field are formed, which is monitored by the receiver coil.

How Metal Detectors Work
 

Metal detectors consist of several parts. Each part has a specific function in order to achieve the basic function of the device, which is metal detection. These parts show how metal detectors work:

1.  The search coil, which consists of two coils, one for transmitting the magnetic field and the other for receiving the field returning from the target.

2. The control box, which contains the transmitting circuit and the receiving circuit of the device.

3. The battery, which provides the energy needed to generate the magnetic field.

4. The column, which connects the search coil to the control box and can be adjusted according to the person using it.

5. Headphones, Some metal detectors have headphones to help hear existing metal detection signals, especially in noisy areas.

Uses of metal detectors

Metal detectors are widely used and rely on electromagnetic waves. People use metal detectors in many fields such as:

1. Construction field: metal detectors work to identify metal objects such as pipes and wires located in the wall or underground. This helps avoid damaging anything when preparing a new construction site.

2. Food industries: Metal detectors play a very important role in detecting metallic substances that cause contamination of food, which may negatively affect human health and cause many diseases.

3. In the field of archaeology: archaeologists rely on metal detectors to search and excavate archaeological and historical artifacts of ancient civilizations.

4. In the security sector: the use of metal detectors has increased recently in airports and public places. The aim is to search for dangerous weapons and metals that may pose a threat to people's safety.

5. Mining industries: modification industries depend on detecting underground minerals.

6. The hobby of searching for lost things: treasure hunters and hobbyists use metal detectors to search and excavate for coins and jewelry buried on the beach.

3D metal detectors

How Metal Detectors Work[/caption]

3D imaging metal detectors are devices that are used for ground surveying with the aim of detecting metals buried underground, so that a 3D image appears on the computer screen in the form of a 3D outline of the metal object.

This type of metal detectors is characterized by high accuracy, in addition to covering a very wide search area. You can get accurate results for metals buried underground, as these devices reach very long depths in the ground.

One of the most important 3D metal detectors is the Gold vision 3D metal detector device, which is used to detect gold and metals of all kinds. This device works with multiple detection techniques to increase the accuracy of the search, increase the range, and estimate the depth at which the metal is located.

What metals cannot be detected using a metal detector?

Although metal detectors use a powerful transmitter coil to transmit the magnetic field as well as a receiver coil, they cannot detect some metals such as:

1. Stainless steel, because the electrical conductivity of this metal is very poor, and therefore its magnetic permeability is very low, so metal detectors find it difficult to detect it.

2. Titanium, this metal is strong and resistant to corrosion. Therefore, it is used in dental implants. The metal detector cannot determine its location due to its low electrical conductivity and thus low magnetic permeability.

3. Some other metals, such as gemstones and pearls, cannot be located by metal detectors.

What gets detected in a metal detector?

The metal detector detects many types of metals, such as iron, nickel, and cobalt, in addition to gold, silver, and other metal pieces buried in the ground. Therefore, these devices can be used to detect buried treasures underground by archaeologists.

The metal detector can also be used to detect metal weapons among passengers at airports, train and metro stations, and this contributes to enhancing security protection for passengers and maintaining public safety.

How do human metal detectors work?

When an electric current passes through the wires of metal detectors, a magnetic field is generated across the transmitter coil.

When this field passes through something made of metal, the magnetic field lines noticeably change. This change is read by the device to indicate the presence of a piece of metal in this location.

These devices can detect all types of metals, whether ferrous or non-ferrous. The strength of the signals varies depending on the location of the coin, so It is possible to determine how far the coin is from the device.

Do metal detectors detect every metal?

Metal detectors can detect a very large number of metals, especially ferrous metals, due to the magnetic properties they possess, such as Iron. It can also detect non-ferrous metals such as nickel, aluminum and zinc.

Despite its ability to detect all these types of metals, it may not be able to detect some other metals, such as titanium and stainless steel, as metal detectors find it very difficult to detect these types of metals.

Do metal detectors pick up gold?

Although the ability of metal detectors varies from one device to another, most of them have the ability to find iron and gold, but their ability to find iron is greater because the conductivity of iron is greater than that of gold.

Many people prefer to use metal detectors on beaches to find coins buried in the sand as well as search for lost treasures and gold.