CENTRIFUGE TECHNOLOGY



The Decanter Centrifuge, as illustrated, is used to separate the solids from volumes of liquid that contain solid particles. This may be a process stream or a waste product from a process.

This separation effect occurs in just the same way as it would in a settling tank but in the case of the centrifuge the tank is in the form of a stainless steel bowl that is spun at high speed. This increases gravity from a factor of one as in nature, up to three thousand in some cases. The settled solids accumulate at the bowl wall and are then discharged by means of a helicoidally shaped screw known as a scroll, which pushes the solids from the cylindrical section of the bowl, up through the conical section and towards the discharge ports. The liquid phase, known as the centrate, finds its way back down the centrifuge bowl where it flows out over a “weir plate”, as it would in a lagoon, and falling by gravity down the discharge pipe.

The process of separating the liquid from the solid matter is sometimes called dewatering. In waste streams centrifuges are used to minimise the amount of liquid that is being hauled away, and produce solids suitable for disposal to landfill sites, land spreading or even incineration. In certain processes chemical flocculants may be added to aid the process of separation.