Method and device for the production of pure steam

An apparatus for purifying an evaporation product to produce purified steam, the apparatus comprising:

• a falling film evaporator;
• a downpipe for receiving the evaporation product from the falling-film evaporator;
• a pressure vessel defined by an outer shell, the outer shell surrounding the downpipe and defining a reject water reservoir in a lower portion thereof, an upper surface of the reject water reservoir being disposed below and spaced from a lower end of the downpipe;
• an intermediate shell mounted in the pressure vessel outer shell to define a condensate return path therebetween and surrounding the downpipe, a lower end of the intermediate shell being disposed below an upper surface of the reject water in the reject water reservoir;
• a rising channel including spiral fins mounted between the downpipe and the intermediate shell to define a spiral path for the evaporation product to rise upward therethrough;
• at least one aperture in the intermediate shell adjacent the spiral fins such that water droplets and contaminants in the evaporation product moving along the spiral path are propelled centrifugally through the aperture;
• a cooling jacket on the outer shell vertically aligned with the fins and displaced from the intermediate shell for actively cooling a surface of the outer shell to condense water droplets which passed through the at least one aperture.