The Reineveld centrifuge is a mechanical device using the principle of centrifugal force to separate substances of different densities. It is applicable for liquid and solid separation. The shaft is positioned on the horizontal axis and the basket has a perforated wall designed for the evacuation of the effluent stream. It is particularly suited for the dewatering of fine crystalline or granular solids. The particles measure in the 2 to 100 micron range.

Dewatering is performed by both filtration and sedimentation in the centrifugal field. During the filling phase the liquid passes through the cake and exits via a filter cloth through the basket perforations; this is the filtration phase. As the cake bed is formed and the solid level progresses, it will cause the liquid to rise over the basket rim; this is the sedimentation phase. The majority of the dewatering (estimated at 80 percent) is achieved by sedimentation; the remaining is accomplished by filtration.

The Reineveld centrifuge is a batch machine and the operations are controlled by an auto/manual computer control system. The hydraulic and pneumatic functions of the centrifuge are controlled by sensors, adjustable cycle timers and interlock relays. A batch cycle consists of: fast fill, slow fill, spin-1, wash, spin-2, and unload steps. All functions take place at a constant basket speed. Certain products require spin-1 and wash steps to flush out the impurities that settle on the cake surface; these two steps are typically not needed in starch applications.

The cycle begins with the fast fill step. The flow is governed by two Reineveld pneumatic operated stainless steel feed valves. The slurry enters through the feed pipe that distributes it over the width of the basket. A spoon and knife load sensor detects the liquid or solid level inside the basket. The load sensors have a signal that is set to activate when the liquid or solid level reaches the basket rim. The automatic load feeler operates in conjunction with the slow feed timer. Timers are used only as a safety back-up system in case the sensors should fail.

The spoon load sensor has a hydrofoil on the end of its arm. It rides on the surface of the liquid in the basket. As the liquid level reaches the basket rim, the spoon feeler will turn-off the fast feed valve and start the slow fill cycle. The centrifuge will continue to be fed by the slow feed valve.

In the slow fill step the feeler arm is shaped like a knife. It is designed to cut through the slurry and ride on the cake surface. As the cake level reaches the rim of the basket, the knife feeler will turn off the slow feed valve and commence the spin cycle. This completes the fill cycle.

During the spin cycle, the cake continues to be dewatered by filtration. A cycle timer controls the spin time and can be adjusted based on the type of product. As the spin cycle expires the unloading cycle will begin.

The plough will travel vertically with the aid of a hydraulic activator. The cake is cut-out by a special hardened knife made of function-specific material and guided into the screw conveyor. The unloading cycle is complete when the plough reaches the top sensor. The top sensor initiates the load feelers into service and retracts the plough cylinder. As the plough travels down and reaches the lower sensor, it will open the feed valves and reset the timers. The centrifuge is then ready to begin another cycle.