A Rising Film Evaporator comprises a vertical shell-and-tube heat exchanger (Calendria), and a vapour-liquid separator.
The product is fed into the calendria at the bottom. The liquid rises through the tubes. The heat is provided to the tubes which heats the liquid and creates vapours that rise upwards at very high velocities. Due to this upward movement the liquid rises to the top. The vapours & liquid both enter the attached vapour-liquid separator through the duct, and the vapours & liquid get separated by centrifugal action.
Typically this evaporator is used for a single pass operation.
