Abstract: An evaporator comprising a device for uniform distribution of liquid over the inner surface of crimps in an upper drum constituted as a plate rigidly secured to a rotor shaft and covering the inner space of the drum so that steam passes through an annular clearance between the outer surface of the drum and a heat-exchanging surface of the casing. A centrifugal separation device comprises sections, each positioned between adjacent drums and having vertically disposed blades for discharging the separated liquid to the device for uniform distribution of liquid over the inner surface of the crimp bulges of a lower drum while separated steam passes into the interior of the drum.