Raschig ring

A Raschig ring is a piece of tube, approximately equal in length and diameter, used in large numbers as a packed bed within columns for distillations and other chemical engineering processes. They are usually ceramic, metal or glass and provide a large surface area within the volume of the column for interaction between liquid and gas vapours.

Raschig rings are named after their inventor, German chemist Friedrich Raschig, who patented them in 1914.