High Efficiency Classification system

The Garbuio Dickinson Elutriator is a high efficiency fluidised bed classifier for separating unwanted heavy particles such as knock-outs from dry expanded cut stem. It is also suitable for classification of other granular, free-flowing products such as DIET.

The Elutriator employs vibration to assist fluidisation of the product and convey it through the process. The fluid bed is supported within a chassis which floats on coil springs, and is vibrated by two contra-rotating vibro motors.

Air is drawn into a plenum chamber through inlet filters by variable speed inlet fan(s). This air then passes through finely perforated stainless steel diffuser plates where it contacts and fluidises the tobacco.

The fluidised bed is divided into two zones: the first zone has a relatively low airflow so that only the lightest portion of the product is lifted at this point. This reduces the material load on the subsequent higher airflow zone, so that a greater separation efficiency and selectivity can be achieved. The classification process effectively occurs within the fluid bed.

The light material that is ejected upwards from the bed is gathered by a conveying air stream within the converging hood of the machine. The convergent hood design avoids recirculation of material within the hood which would otherwise increase the material loading and reduce overall efficiency.

The product is pneumatically conveyed and separated from the air stream by an APS or tangential separator, and the air is exhausted via a dust collector. Automatic controls ensure that the pneumatic conveying air flow is equal to the injection air flow. The degree of classification is simply adjusted by varying the injection fan speed via up/down push button controls located so that the classification performance can be easily observed.