A metal detector is a device designed to detect metals deep underground or in the water. On invention, metal detectors were designed for security purposes screening and also to locate mines. Some industries like chemical industries, food processing industries, pharmaceutical industries and even packaging and plastic industries also use the metal detectors to detect metal debris in the products. How exactly does a metal detector detect hidden metals?
How metal detectors work.
Metal detectors operate under the principle that whenever electric current passes through a loop, it will produce a magnetic field. A magnetic field is generated when an alternating current pass through the transmittal coil which is in the metal detectors. One of the essential parts in the metal detectors is the oscillator which produces the alternating current. When a conductor or a metallic object is placed close to the coil, it will generate a current that will produce anther magnetic field. A receiver coil can also be found in the detector as it also detects changes in magnetic field in the presence of another metallic object. Very Low Frequency (VLF), Beat Frequency Oscillator (BFO) and Pulse Induction (PI) are the common technologies used in the latest models of metal detectors.
Very Low-Frequency Technology (VLF)
Metal detectors have two sets of coils; a transmitter coil and a receiver coil. The electric current is sent to the transmitter coil and creates a magnetic field. The magnetic field ten gets generated y the metal detector and reacts when a conductor or any metallic object passes on it. The receiver coil which is protected from the magnetic field the transmitter coils produces is only affected by a conductor's or metallic object's magnetic field. The electricity that runs through the receiver produces a weaker magnetic field when a conductor gets near the detector. The receiver coil amplifies and sends the frequency equal to the one of the magnetic field generated by the metal for analysis in the control box. This way the metal detector working on very low frequency determines differences in the metals.
Beat Frequency Oscillator Technology (BFO)
The BFL just like the VLF that uses two wire coils. The first coil is found in the control box and is smaller than the second coil. The two coils are connected in the oscillator that sends out thousands of electric pulses per second. When the pulses pass through every coil, you will hear clear tones like of the radio 1wave frequency created by the receiver. in case another magnetic field is detected, the creation of the radio waves is interfered with. This produces a change in tone in the receiver helping detect the metals in target.
Pulse Induction Technology (Pl)
Unlike the BFD and VLF, this uses a single coil. It is however also possible to use two or three coils. Metal detectors using this kind of technology send short pulses of current to the coil, to generate shorter magnetic fields. In every pulse, the magnetic field generated reverses the polarity and eventually collapses. When the magnetic field pulse collapses, a current referred to as a reflected pulse occurs and runs through the coil. The reflected pulse only lasts seconds. The reflected pulses will, however, last longer if a conductor or metallic object gets in contact with the metal detector. This is because of the opposite magnetic field produced by the detector. The metal detector on noting the signal reads and amplifies the signal to a direct current. A tone will then be produced to indicate detected presence of a metallic object.
How to choose the best metal detector
If you are out to purchase a metal detector below are a few things you should put into consideration;
Some metal detectors are quite expensive; you can, however, cut the cost by buying what you need. Know the features that you want and purchase the detector that has just those features. You can also look out for big brands of metal detectors as they come at reasonably lower prices.
Where you are going to use the metal detector
Where you are going to use, the detector determines the kind that you need. if it's by the beach, a waterproof detector will save you the cost of buying another one soon. If it is mountain areas, there are some designed for such terrains too.
Some detectors come with target indicators. This helps identify the kind of metal detected by putting into categories like iron, nickel, zinc, dime and much more. This will save you the time of digging out a metal you are not interested in.
Some metal detectors will have an indicator to show how deep a target is below the ground. This comes in handy for discovering how deep you must dig to retrieve the metal.
Sometimes the signal from the soil is stronger than the signal from the metal. Some field can contain a large volume of iron which makes the metal detector impossible to use. Ground balancing erases the effects of minerals on the ground. If you are targeting a highly-mineralized region, it is advisable to put this in consideration.
A metal detector during use has to deliver accurate detection. it should be able to detect treasures in a very precise way. lf it can't detect objects a small as jewelry, then it is not worth your money.
The ability of the detector to be upgraded is quite crucial. Other devices should be able to be added to it to improve its performance. The more the devices that can be mounted to it the better.
it is always advisable to buy a metal detector that can withstand wear and tear for the longest time possible. The longer the metal detector serves you, the higher your returns will be.
Buying a metal detector is a big decision and getting the right one is even harder. If you want to purchase a metal detector, l believe you by now perfectly understand its functionality and what to look for.