Evaporation is the process in which from one end solution is being entered in diluted form and at the other end it comes out in liquid but in concentrated form. This dilute to concentration is being converted by applying heat by any means, vapour separator and other instruments between these two end. This single stage evaporation is very costly. Looking to the requirement and solution at present multistage system is used in which its vapour energy of the one stage is used for the next stage where the liquid is still to be concentrated. There are various types of evaporators.