Gravitational Classifier

Feed material is dropped in a continuous feed curtain and enters the classifier at the top of the unit. Low velocity air enters the classifier at inlet and is forced through the feed curtain which is dropping in front of the air outlet provided with widely spaced vanes. The air stream enters the feed curtain perpendicularly, but is changed to an almost parallel, but reverse direction to the feed curtain as it passes through the vane.

Buell gravitational classifiers separate articles at any predetermined cutpoint between 100 mesh and 10 mesh (150 to 1651 microns).

Power requirements are extremely low; most energy lost is due to the change of direction of the air stream as it is exhausted through the vanes. To effect classification, the resistance to gas flow or draft loss ranges from 0.5” W.G. to 4.0” W.G., depending on the cutpoint and feed-to-air ratio. The higher the cutpoint, the higher the draft loss. The gas flow through the vanes must be increased to provide a high drag force. The volume of gas-to-feed ratio ranges from 150 to 300 cfm per ton per hour of classified feed.

View our Gravitational Classifier Video