To execute cleaning and maintenance of an automatic vacuum distiller wherein, though the automatic vacuum distiller is smaller in size principally, an indirect heating exchanger having a necessary heating area is contained in a smaller capacity distiller therefor in a higher density, and though it becomes heavy weighted owing to the high density, it is easily extracted by a small number of operators.

The heat exchanger is made spirally coiled, a plurality of spiral pipe coils (1), (2) and (3) the diameters and the number of windings of which are mutually different are combined, and the heat exchangers each having a necessary heating area are contained in a high density in the distiller (4) of the minimum capacity. As a countermeasure for making heavy weighted, the distiller (4) is made into a cylindrically vertical type having a flange on a side, a plurality of the spirally coiled pipe heat exchangers are allowed to pass through one plate of the flange (5) and be fixed by welding to make a complete set. Further, one piece of a small wheel (13) in the distiller (4) and two pieces of small wheels (14) are fitted to both ends of an outside flange part, and cleaning and maintenance are made easy by adopting broadwise extraction.