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How a metal detector works
You might believe that metal detector uses limited to professionals and amateurs who wish to access the underlying metal underground, but in fact the metal detector has multiple process applications for example used in the inspection by security personnel at the entrance to places that require a high degree of safety and security such as airports and tourist places, these devices have become the requirements of safety and security in airports, universities, schools, theatres, government buildings to ensure no armed persons not entered into these buildings. This is in addition to their uses in exploration and search for underground minerals.
You can spend hours of fun in the search for precious metals buried in the ground using metal detectors
In this article of how things work we will explain how to store metal detectors and using special devices called metal detectors.
Metal detector components
A metal detector consists of simple lightweight parts as follows:
(1) the organizer or installer stabilizer used in maintaining a fixed and stable machine parts while moving the machine forward and backward.
(2) control box control box containing electronic circuits and controllers and battery walmikrobrossor and speakers.
(3) the column shaft connecting the detector control box and usually controllable column in length to fit the length of the person’s user
(4) detector search coil and is the main part in the device and is used to detect the presence of minerals and is sometimes called brass aggregates search head or alantenna loop antenna or file. “We will use Musleh detector”.
There may be some types of metal detectors some minor differences such as to provide the additional headset or remote control at the bottom of the column and the monitor installed at the top. But all metal detectors are easy to use, all you have to do is turn on the device and move it slowly over the area detector to detect metal. When there is a metal piece, the machine will beep through headphones as it appears on the screen some information about a plot and depth.
Types of metal detectors
Metal detectors depend on three techniques identify types and these techniques are:
Low frequency technology Very low frequency (VLF)
Magnetic pulse induction technology Pulse induction (PI)
Oscillatory Beat-frequency oscillation pulses technique (BFO)
We will now explain the idea of work each technique of the three techniques and how to use the metal detector.
First: Very low frequencies low frequency (VLF)
This technique is most commonly used in metal detectors, sometimes known as almanatisi induction induction balance balance this technique relies on the use of two files:
File transmitter transmitter coil is the external file and contains a loop of wire passes through the outlet once clockwise and counterclockwise rotation up to thousands of times per second.
File reception receiver coil and internal file that contains wire in the form of a RADIUS smaller than the send file and this file work alantenna to receive the signal reflected from objects in the ground and grow.
Metal detector technology to low frequencies
To AC outlet that passes in the send file creates a magnetically, the direction of the magnetic field vertically on level transmission file, and every time it changes the current direction change polarity (Arctic and Antarctic) magnetic field. This means that if the send file level parallel to the surface of the Earth, the magnetic field created in the Earth or out in the resembled the pull and the push.
While the magnetic field impulses entering and exiting Earth interact with any conductive materials (e.g. minerals) collide, and this causes conductive materials would generate weak magnetic field is called the magnetic field of the body and be the polar opposite magnetic field polarity for file transmission. If the file in the direction of access to land is the area of the body toward the exit and vice versa.
We come now to the role of file reception to explain how magnetic signal receives reflective metal body, here a reception completely cut off from any magnetic field produced by a transmitter, but not isolated from the magnetic field of the metal body on the Earth. Therefore, when passing a receiver over a metal object emits a magnetically because file transmission, the receiver will file captures this weak magnetic field and AC and produces electrically tiara over a file receiver, frequented the same outlet frequency domain almghanatabisi. This outlet is maximized and interference to altgkem where the almikrobrossor signal analysis and show data.
Note: to understand the relationship between the pass-through outlet in Mosul and magnetic field please see how it works and how it works, compressor electric motor?
A metal detector to determine the depth of the metal body on the ground depending on the intensity of the magnetic field generated by the metal body, whenever the body close to the Earth’s surface where the magnetic field arising more and more electrical signal generated in a larger reception whenever the body at a depth greater than the Earth’s surface where the magnetic field is smaller by adjusting the magnetic field strength with depth device can that locates the body and its distance from the Earth’s surface.
How a metal detector distinguishes between different types of metals?
May not imagine how many minerals that can ytlkotha a metal detector and ultimately be either a small nail or a drink from the almshorbat or pieces of junk that’s been developing metal detectors to let you differentiate between metal, predetermined for the device type of metal you want to find as gold or other so it doesn’t give the device the audio signal only if created the metal you are looking for, but how can a metal detector distinguish between types of metal we understand how Select depth and the process was easy and obvious but should distinguish between minerals, this really is difficult and depends on electronic circuits you measure phase shifting phase offset.
Phase offset is the difference in time between the send file and frequency frequency of the body. This difference in time was due to a difference in electrical resistance and resistance to induce electrical inductance
The body which does not pass the outlet easily (with resistance) be faster in responding to changes in the outlet.
Either the body that connects outlet easily it is slower in responding to changes in the outlet.
This means that the body has urged large electric have large phase shift amount to take more time with the magnetic field change objects with large electric resistance the phase offset will be small.
Relying on electronic circuits besbith can calculate the offset in phase and compare previously stored information offset from the offset in phase of various minerals that device can distinguish between minerals can thus programming a metal detector to look for minerals that have a certain phase shift that we want.
II: magnetic pulse induction technology
Magnetic pulse induction technology is less commonly used in metal detectors that relying on this technique cannot distinguish between the types of minerals in the first but technical devices that support this technique works in certain areas where the first technical use as we will see after we explain the idea of working reagents based magnetic pulse induction technology.
This technique uses one file works as a file send and receive at the same time. Support the idea of this technique to send a power short pulses and strong component file of wire on a circular shape. Each pulse of these pulses generate a magnetically. Once the pulse magnetic field polarity is reflected and fading magnetic field suddenly forming in this way a spark of AC/DC. Lifetime of the electric spark does not exceed µs (ppm of a second) cause this spark electrical outlet in password file. This is called power output of electrical spark as the reflected pulse reflected pulse and be very short duration not exceeding 30 microseconds. This process is repeated at a rate of 100 beats per second and can change this number to up to 25 beats per second or more than 1,000 beats per second depending on the manufacturer.
Metal detector technology to magnetic pulse induction
How can a metal detecting metal detecting with this technology?
When the detector over a metal object the electrical pulse produced a magnetically in the body. When magnetic pulse faded and causing the reflected pulse pulse reflected the additional magnetic field induced metal body will increase the survival time of the reflected pulse. This process is similar to perfectly echo phenomenon more reflectors (walls), the echo sound lasts longer.
Using the circuit monitors the reflected pulse duration might determine whether there is room for additional magnetic because of increased survival time of the reflected pulse. If the time exceeds the expected value, the device sends an electrical signal morphing across circuit to bigger and sent to the Department issued an alarm beep metal body in the area disclosed.
Advantages and disadvantages of magnetic pulse induction technology
Reagents technology magnetic pulse induction as mentioned at the outset cannot distinguish between types of minerals for the duration of the reflected pulse does not differ significantly between metals. But this technique is very useful in cases where you cannot use the reagents with low frequencies due to terrain that scrutiny if the Earth contains materials with high conductivity prefers to use magnetic pulse induction detectors, these reagents can detect minerals deeper spaces of those other systems can be monitored.
III: oscillatory pulses technique
Oscillatory impulses is one of the easiest techniques used in metal detectors. Large file being used when the search party and another smaller file located inside the control box. And each file attached to the oscillator generates thousands of pulses per second.
The file renders waves radio reception by the receiver in the control box and turning it into a beep heard a heartbeat caused by the difference in frequency in the two files.
When a large file over a metal object, the magnetic field generated by the electrical outlet in the file. Telescoping magnetic field of metal body with radio waves, this leads to deviation in frequency of the radio waves and radio waves is different from the file in the control box, this generates a tone audible buzz.
And technical idea simply oscillatory impulses, many producers have adopted this technique for metal detectors for low cost and possibility of purchase by anyone and use as an instrument of appliances. But we must note that the accuracy and sensitivity of these devices less than those that support the above techniques.
Metal detectors operate efficiently to detect metal objects buried in the ground. But keep in mind that these devices do not exceed 30 cm depth sensitivity and amount of depth depends on several factors:
(1) type metal detector
(2) the type of metal you’re looking for
(3) the size and dimensions metal body
(4) the nature of the soil
(5) the overlap between the body and the surrounding objects
The controller used in the metal detector the oscillatory impulses
Is regarded by many as metal detecting hobby and special clubs for them to do some activities such as
(1) search for money
(2) the search for precious metals such as gold and silver
Use in security systems, safety and protection
In addition to the multiple uses of metal detectors with different technologies, there are other important uses. The surveillance devices installed at the entrances to important institutions such as airports used metal detector technology magnetic pulse induction manual inspection equipment used by security officers using metal detectors with oscillatory impulses.
Security Portal powered by metal detector
Some important applications of metal detectors:
Airport security: Gates Unveils minerals before boarding the plane.
Building security: Gates are also used to detect metals for visitors before entering the building.
Search for lost items: anyone can use a metal detector to search for jewelry pieces are missing.
Uncover effects: used to detect metals of historic significance.
Geological detection: used in geological examination of soil and rocks.
Hand-held metal detectors for security personnel
Finally, many producers of these devices has always sought to develop their products to become more precise, more sensitive and more user-friendly. If you dear readers of amateur search for minerals must you be contemplating the acquisition of one of these devices one owns perhaps hope idea work machine has been you.