Why are the disks in a disk-type centrifuge shaped like cones?

In a disk-type centrifuge, the disks are shaped like cones to create a narrow space between adjacent surfaces where sedimentation occurs. This design significantly reduces the settling distance for particles, which effectively increases the rate of separation.1

The specific angle of these cones is engineered so that once heavier material reaches the inside surface of a cone, it slides down along that surface, facilitating efficient collection. This configuration is particularly effective for the continuous separation of liquids containing low concentrations of solid or immiscible components, such as in a cream separator or for the purification of fuel oil.1