VIBRATIONAL SCREEN (EN: vibrating screen, vibroshaker, vibrocribble, racking screen; DE: Schwingsieb, Vibrationssieb; FR: vibrotamis, crible vibrant; ES: criba vibratoria; RU: вибрационный грохот) is the machine with the vibrational mover, which is purposed for the sorting (screening) of the loose materials, using the method of the sifting of these materials through the sieves (or through the grates).
The vibrational screen (see the Figure) is the most widespread group of the screens, which are used within the mining industry. They distinguish the vibrational screens with the mover from the eccentric mechanism, namely, the eccentric screens, or the gyratory screens, and the screens with the mover from the vibrator, namely, the inertial screens; the resonant vibrational screens are the sub-type of the latter screens.
The working tools of the vibrational screen are the sieves (or the grates), which are rigidly fixed within the box, to which there are imparted the periodic oscillations, as the result of which action, there proceeds the moving and shaking of the material, which is being sorted, and the sifting of this material through the cells of the sieves (or of the grates), that is, the division into the fractions according to the size. The sieves are usually placed into the 2-3 tiers; each following tier (which is located lower) has the sieves with the smaller cells. The sieving surfaces of the sieves are the steel wire meshes; the surfaces of the grates are either the stamped steel sheet with the holes, or the set of the grid-irons (which have been made of the steel, rubber, or plastic).
The box of the vibrational screen is placed horizontally, or is inclined. With the inclined box, there are produced the eccentric and inertial vibrational screens; with the horizontal box, there are produced only the eccentric screens. There have obtained the greatest distribution the eccentric and inertial vibrational screens with the inclined box (within the USSR, of the GGT-42, and GGS-42 marks, with the performance of 250 and 150 cubic metres per hour), which they use for the isolation of the marketable fractions of the coal, ore, and building materials. For the intermediate sorting of the materials (under the more severe conditions of the work), they use more often the eccentric inclined vibrational screens. They usually include the horizontal inertial vibrational screens into the structure of the movable crushing-screening installations, where these screens are used for the preliminary sorting of the materials (in case of the usage of the grid-iron grates), or for the marketable and intermediate sorting (in case of the usage of the sieves and grates). There are the promising structure the resonant vibrational screens, which require the lesser power of the mover; besides this fact, the balance of the masses within these structures permits to create the screens with the large screening surfaces.
Within the USSR, there are produced the resonant vibrational screens of the GRL 62-1 mark with the performance of 80 cubic metres per hour. The quantity of the vibrational screens at the large crushing-screening plants reaches 8-15 (depending on the material, which is sorted), with the total area of the screening surface of 100-500 square metres.
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