The gravity separator and destoner, also known as an air table, All gravity separators have five variable adjustments that must be properly adjusted and balanced to obtain optimum separations. These are: feed rate, end raise, side tilt, eccentric speed, and air control. The feed rate control is located on the feeder and governs the amount fed onto the separating deck. For optimum separation on your Gravity Separator, the feed rate should be as low as possible without falling below the minimum feed rate at which the deck can be kept completely covered. End raise is the slope from the feed end of the deck to the discharge end. Side tilt is the difference in elevation between the high side of the deck and the low side of the deck. Eccentric speed and side tilt are closely related. lncreasing eccentric speed will cause material to be shifted toward the high side of the deck.Air regulation is one of the most important adjustments to be made on a Gravity Separator. About 250 B.C., Archimedes discovered the law of specific gravity which is: "ALL BODIES FLOATING IN OR SUBMERGED IN A LlQUlD ARE BUOYED UP BY A FORCE EXACTLY EQUAL TO THE WEIGHT OF THE LlQUlD THEY DISPLACE." The specific gravity of a particle is the ratio of its density to some standard substance, the standard usually employed being water with a specific gravity of one (1). Particles having a specific gravity of less than 1 will float, and particles with a specific gravity greater than 1 will sink. All gravity separators use air as a standard rather than water. Since air is lighter than water, the relative difference between particles of differing weights is increased. For this reason, the gravity separator is a very sensitive machine and, when operated correctly, can produce a very precise separation.
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