What is a Decanter Centrifuge?

Horizontal Bowl centrifuges are also known as decanter centrifuges, centrifugal decanters or simply decanter machines and are primarily used for separation of liquids from appreciable amounts of solids. Decanters can separate over 50% (v/v) solids from liquids on a continuous basis. Typical industrial decanter applications include Crude Oil Tank Bottoms; Waste Oil; Industrial Waste-water; Sludge Dewatering; Fish Meal; WVO/UVO De-Sludging; Paint Sludge; Rendering etc. etc.

How does it work?

A decanter centrifuge separates solids from one or two liquid phases in one single continuous process. This is done using centrifugal forces that can be well beyond 3000 times greater than gravity. When subject to such forces, the denser solid particles are pressed outwards against the rotating bowl wall, while the less dense liquid phase forms a concentric inner layer. Different dam plates are used to vary the depth of the liquid or ‘the pond’ – as required.

The sediment formed by the solid particles is continuously removed by the screw conveyor, which rotates at a different speed than the bowl. As a result, the solids are gradually “ploughed” out of the pond and up the conical “beach”. The centrifugal force compacts the solids and expels the surplus liquid. The dried solids then discharge from the bowl. The clarified liquid phase or phases overflow the dam plates situated at the opposite end of the bowl.

Why Dolphin?

Dolphin has been buying, refurbishing and stocking/selling gently used Alfa Laval & Sharples decanters. As part of the rebuilding decanters – we routinely tungsten carbide hard-surfacing to the conveyor, install carbide tiles, stellite sludge-port liners etc. VFD back-drives are installed for auger speed control and over-torque sensing clutches are also installed. Options such as pillow-block temperature sensors, main-drive / back-drive interlocks, main-drive current monitors and other features are common in our Dolphin Decanter Control Panels.

Our current Alfa Laval stock includes: Alfa Laval NX418 2-phase; Alfa Laval NX418 3-phase; Alfa Laval NX414 2-phase; Alfa Laval NX309 3-phase decanters.
We also have: Sharples P660; Sharples P3000; Sharples P3400 and Sharples P5000 Decanters.