In the evaporator space the soln. which is to be concentrated is boiling continuously while having a free surface and forced circulation. Pressure redn. is provided only by the friction against the walls of the evaporator space. The temp. change along the stream is therefore continuous, providing the equivalent of an infinite number of evaporator stages. In the condenser space the condensate is cooled against the incoming soln. in a similar manner. A third space is provided for de-gassing. This is in a spiral form, wound together with the others. In the de-gasser space boiling releases gases which are partially condensed in a condenser channel by cooling against the incoming soln. Non-condensible gases are removed by vacuum pump or other means.
展开▼
