What Is a Centrifugal Separator?

A centrifugal separator (centrifuge) uses centrifugal force to separate components in liquid–solid or liquid–liquid mixtures. It mainly removes solid particles from suspensions or separates immiscible liquids of different densities. CHINENG outlines what it is, how it is classified, and how it works.

How are centrifuges classified?

1. By speed: low-speed, high-speed, and ultracentrifuges;

2. By temperature need: ambient and refrigerated centrifuges;

3. By rotor: swing-bucket (horizontal) and fixed-angle rotors;

4. By size: floor-standing, benchtop, and mini centrifuges;

5. By grade: standard and precision centrifuges.

Function and operating principle

Centrifuges work by centrifugal filtration or centrifugal sedimentation.

1. Centrifugal filtration

Centrifugal pressure drives liquid through a filter medium (screen or cloth) while solids form a cake on the medium. Filter bowls have perforated walls lined with the medium.

2. Centrifugal sedimentation

Components of different density settle and layer rapidly in the centrifugal field, separating liquid–solid or liquid–liquid mixtures. Sedimentation bowls have no wall perforations.

Feed enters a high-speed bowl; liquid passes the screen to a discharge line while solids remain. When solids reach the set load, feeding stops, solids may be washed, wash liquid is discharged, then the bowl slows and a servo-driven scraper discharges the cake—completing one cycle.

In summary: choose to your process needs, and pay special attention to the rotor—it is a critical part of the machine. Follow the CHINENG website for more updates.