FIELD: drying.
SUBSTANCE: invention relates to food, microbiological and chemical industry and can be used for sublimation drying of frozen solutions or suspensions, sublimation drying of frozen food products. Vacuum sublimation drying unit comprises vacuum drying chamber accommodating ice condenser (desublimator) cooled down to negative temperatures and connected by drain pipeline with condensate collector equipped with boiler communicated through the vapour phase via drain pipeline with ice condenser. Drain pipeline includes rectification column located between ice condenser and condensate collector boiler. Working medium of the rectification column is a mixture of water and a low-boiling agent which forms a low-freezing solution with water. Alternatively, ethyl alcohol can be used as the low-boiling agent.
EFFECT: invention will make it possible to carry out continuous or periodic defrosting of ice condenser surfaces at temperature below 0 °C and at partial pressure of water vapour in ice condenser zone below 610 Pa.
6 cl, 1 dwg
