Chem Falling Film Evaporators are designed to flow liquid and
vapour parallelly downwards. Liquor feed is preheated to boiling temperature. Preheated feed is distributed by a specially designed distributor positioned above the top tube plate of the calandria. An even thin film is formed in the heating tubes and flows downwards at boiling temperature while evaporation. The falling film is 'going with gravity'. This results in a thinner, faster moving film and improved heat transfer co-efficient.

Due to the short times of direct contact and minor differences in
temperature between the heating surface and the solvent, this type is particularly suitable for non-crystallizing solutions which are temperature sensitive; high specific heat transfer.