Used Decanter Extruder-Purchasing Guide

The main technical components of a decanter centrifuge are the screw conveyor and the rotating bowl. Although the screw conveyor and decanter bowl rotate in the same direction, the conveyor rotates at a lower speed. This causes the solids that are pressed outward against the rotating wall to be pushed by the screw conveyor toward the conical end of the bowl.

At the conical end of the bowl, solids are ploughed through discharge openings. To avoid contact with solids, the clarified liquid is discharged through a specific outlet usually at the opposite end of the bowl.

When purchasing a used decanter centrifuge, consider the manufacturer, material of construction, capacity and history of use. Reliable manufacturers include Alfa-Laval, Flottweg, Bird and Westfalia. These brands have similar applications.

When choosing a decanter centrifuge, ensure wetted parts (where the product comes in contact with the machine) are made of high quality stainless steel. If in the food industry, be aware that polished stainless steel prevents the buildup of bacteria. If working with chemical applications, select corrosion resistant metals such as titanium or hastelloy.

There are several capacities to consider when purchasing a decanter centrifuge. The first is the feed capacity, which is the volume of product the centrifuge can process per minute. This can range from 5 GMP (gallons per minute) to 1000 GMP depending on the make and model. Another capacity is the motor for bowl drive that can range from 25 HP to 300 HP subject to make and model. There are also differences in dimensions if space is limited.