Evaporators

An evaporator for eliminating water from liquids or for cooling liquids by direct expansion of a refrigerant fluid, comprising at least three substantially frusto-conical jackets including an outer jacket, an inner jacket and at least one intermediate jacket, said jackets being coaxially superimposed so as to define respective annular spaces therebetween, each of said jackets having a small end and a large end, the ends of the jackets being closed, except the small end of the inner jacket, which is open and communicates with a chamber defined inside the inner jacket;

• inlet and outlet means for a first fluid connected to respective ends of the annular space between the outer jacket and the adjacent intermediate jacket;
• inlet and outlet means for a second fluid respectively connected to the large end of the annular space between the inner jacket and the adjacent intermediate jacket and to the base of the chamber defined inside said inner jacket;
• and a helical element disposed at least in the annular space between said inner jacket and the adjacent intermediate jacket and defining with the adjacent conical surfaces of said annular space, a helical channel leading from the inlet to the outlet of said space, said first fluid being a heat donating or heat accepting fluid, and said second fluid undergoes a change of state while flowing in the helical channel defined between the inner jacket and adjacent intermediate jacket, means for enabling the centrifugal force acting on said second fluid to assist in separating said second fluid into liquid and gaseous phases, the liquid phase being arranged in contact with the inner wall of the intermediate jacket, and including the cross-section of the helical channel between the inner jacket and the adjacent intermediate jacket being dimensioned to increase from the respective inlet means towards the respective outlet means sufficient to accommodate the increased volume of the gaseous phase.