Question

As the film rises further evaporation occurs until they reach the top of the tubes. The mixture of vapor and milk then passes into a separate chamber from which the vapor passes to a condenser. Name the evaporator.

(a) Climbing film evaporator

(b) Falling film evaporator

(c) Plate evaporator

(d) Forced circulation evaporator

I have been asked this question in a job interview.

The doubt is from Evaporator in division Building Blocks of Dairy Processing of Dairy Engineering

Answer 1

The correct option is (a) Climbing film evaporator

To explain I would say: Climbing Film Evaporator, in this type the liquid to be evaporated is fed at the lower end of the vertical tubes, heated by the condensing steam on the outside of the tube. The liquid starts boiling at the bottom; the vapor along with the liquid tends to rise further up the tube in the form of a thin film. As the film rises further evaporation occurs until they reach the top of the tubes.