The material liquid to be concentrated is pumped to the top of the heating tubes, forming a thin film as it flows downward along the inner walls. During this process, the film begins to boil and partially evaporate due to external heating. The remaining liquid and vapor are separated in the lower section of the tubes and downstream separators. Properly managing the flow rate within the tubes prevents dry-out at the bottom and ensures optimal film thickness for the best heat exchange and minimal power consumption. The falling film evaporator supports both cyclic evaporation and one-way evaporation processes.