Mechanical vapor recompression evaporators

A process for providing make-up heat in a mechanical vapour recompression evaporator which comprises introducing the product to be concentrated into a first evaporator, introducing the concentrated product discharged from said evaporator to a second make-up evaporator, the vapour created as a result of the condensation process in said first evaporator being conveyed after processing to the heating unit of said first evaporator, the evaporation vapour created in said make-up evaporator being directed through a vapour-liquid separator to the heating unit of said first evaporator where it serves as make-up heat for the operating cycle of said first evaporator.