Falling film evaporator is the simplest & most commonly used type of film evaporator which is applicable in handling low viscous type of fluid. It is a heat transfer mechanism controlled by conduction and convection across the tubes. In falling film Evaporator Liquid evenly distributed over top tube sheet using uniquely design distributor & tube inserts. Liquid flows under gravitational force as a thin film on the inside of vertical tubes which is heated by steam from outside & resulting vapour normally flows co-currently with the liquid in the center of the tubes. Concentrated liquid & vapour then passes through separator to separate vapour from residual liquid which is then pass on to the condenser.