Evaporators are kind of heat transfer equipments where the transfer mechanism is controlled by natural convection or forced convection. A solution containing a desired product is feed into the evaporator and it is heated by a heat source like steam. Because of the applied heat, the water in the solution is converted into vapour and is condensed while the concentrated solution is either removed or feed into a second evaporator for further concentration. If a single evaporator is used for the concentration of any solution, it is called a single effect evaporator system and if more than one evaporator is used for the concentration of any solution, it is called a multiple effect evaporator system. In a multiple effect evaporator the vapour from one evaporator is fed into the steam chest of the other evaporator. In such a system, the heat from the original steam fed into the system is reused in the successive effects.