SPECIFIC GRAVITY SEPARATOR |seed and grain cleaning|Oliver Manufacturing Company|specific gravity separator|destoner Keep in mind at all times that the Oliver Specific Gravity Separator isnot a "cure all" for the processor's problems. The gravity separator is a specialized piece of machinery designed to separate particles of a similar size that differ in weight, eliminating light trash. Oliver specific gravity separators should not be used as a cleaning machine to remove dust, dirt, sticks and other refuse frequently found in harvested crops. The specific gravity separator should not be used as a sizing machine. Screening machines can do this job more efficiently. In all processing situations, the best results are obtained on the gravity when the product has been thoroughly pre-cleaned and sized, using the proper equipment for those purposes. Under these conditions, the gravity separator is able to show what it can really do! Air is used as the separating standard through the process of stratification. Stratification occurs by forcing air through the particle mixture so that the particles rise or fall by their relative weight to the air. The more difficult the separation, the greater is the area that is required to obtain proper stratification. For example: The stratification area is large when separating frosted beans from saleable beans, because there is relatively little difference in weight. However, the stratification area is small when removing insect damaged peas from whole peas because there is a large difference in weight. Higher capacities, likewise, require higher areas for stratification. In many separations, the distinction between heavy particles and lighter particles is not visible to the unaided eye. In this case, periodic testing for weight per test volume (weight per bushel or weight per cubic foot) at various points along the discharge would be necessary to determine if the correct separation is being made. The discharge from the specific gravity separator is a continuously graded product ranging from the heaviest particle on the high side of the deck to the lightest particle along the low side of the deck. In practice, this continuous grade is normally broken down into three products; (1) a heavy or acceptable product, (2) a light or reject product, (3) a small middling product. In processing where rocks or other heavy trash might be present, a fourth product can be extracted, consisting primarily of dirt, rocks or other heavy rejects. |
