AbstractsEngineering

The use of steam-heated vessels for evaporation has been known for many centuries. The discovery of this method is usually ascribed to one of the early alchemists although Von Lippman (1) claims that the Greeks had already used steam baths in their study of the sciences many years before. The sugar industry has been the greatest single contributor to evaporator design in the modern sense of the word. The quarter century 1800-1825 saw the development of the first vacuum pans for the concentration or sugar. One of the earliest was the “Roth Pan”, which appeared about 1825. Based on an original idea advanced by Howard in 1812, it utilized the direct condensation of vapour in presence of cooling water. Multiple effect evaporation came into use eometime during the period 1840-1850, when N. Rillieux built an evaporator based on this principle in Louisiana in 1843. This apparatus was covered by patent (2), but does not seem to be the first to describe the principle of multiple effects. Apparently Peclet (3) suggested using vapour from a boiling liquid to heat a second boiler, but never developed the idea practically. Other workers about this time were Pecquer, who described a multiple effect under pressure in a single body in 1834, and Degrande, who used a type of film evaporator for sugar juices heated by vapour from a first effect. Neither of these evaporators came into general use. Rillieux’s evaporator was of the type now known as horizontal tube, steam inside type. [...]