Raschig rings
Raschig rings are pieces 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 or metal, alumina ball and provide a large surface area within the volume of the column for interaction between liquid and gas or vapour. Raschig rings are named after their inventor, the German chemist Friedrich Raschig.
They form what is now known as random packing, and enabled Raschig to perform distillations of much greater efficiency than his competitors using fractional distillation columns with trays.