A multi effect evaporator is a device used in industrial production, which uses the principle of evaporation to evaporate the water in the solution and obtain a concentrated solution. The working principle of a multi effect evaporator is to use multiple evaporators connected in series to form a multi-stage evaporation system. In this system, the steam from the previous stage evaporator serves as the heating steam for the next stage evaporator, thus achieving a cascade utilization of energy.