Work principle Metal detector
The metal detector-it the electronic device which finds out metal presence without contacting to it (thanks to radiation of radio-waves and catching of secondary signals), and, having found out, informs the operator. In the search coil the electromagnetic field which extends in environment, whether it be the earth, a stone, water, a tree, air is created. On a surface of the metals which have got to an operative range of the search coil, under the influence of an electromagnetic field there are so-called vortical currents. These vortical currents create own counter electromagnetic fields leading to decrease of capacity of an electromagnetic field, created by the search coil, as is fixed by an electronic circuitry of the instrument. The difference between cheap and expensive models consists only in methods of radiation of radio-waves and methods of catching, processing and interpretation of secondary signals. More expensive device can define with known degree of probability type of the found out metal before its extraction, to define its depth zaleganija, can build up from ground minerals, and also have many the various additional functions increasing productivity and efficiency of search which are absent at cheap devices.
Functions Metal detector
metallodetektor for superficial search should possess following functions: · discrimination (distinction colour and ferrous metals); · possibility of elimination of dust (a stopper, a foil, nails); · a mode static pinpointa (exact detection of the purpose without mahovogo coil movements); · indication of type of the purpose and depth zaleganija object on the screen is desirable; · possibility manual otstrojki balance of a ground (an exception of influence of a mineralization of a ground). It is necessary to distinguish devices for two principal views of superficial search: search of coins, buttons, ancient elements of a life; and search of military artefacts. metallodetektory for each of problems have the features - for example, accuracy of elimination of a rust, scale, splinters, sleeves. For military archeology the greatest results are reached at use of deep devices, they differ from superficial devices structurally, have no discrimination, but allow to search on depths to 5 metres, do not react to small subjects (sleeves, splinters). All devices for superficial search have depth of search for coins of 20-35 sm, about 60-100 sm for a helmet, is maximum - 1,5-2 metres (for very large subjects - a flank, trak). Accuracy of the discriminator is limited 20-25 sm, distinction of type of metal not is deeper so is truly defined, though the object is fixed.
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