| 摘要 |
PURPOSE:To eliminate instability in a flow of liquids to be concentrated on a heat transfer plate and unnecessitate a preheater of separate construction, by causing a vacuum flushing of preheated liquids which are to be concentrated when said liquids are delivered from the upper end of an upward passage, whereby increasing instantaneous flowing speed of said liquids so that said liquids are dispersed in a thin filmy state. CONSTITUTION:In a plate-type evaporator having a laminated construction, comprising a plurality of first heat transfer plates 30 having a supply port 31 and a discharge port 32 for liquids to be concentrated and second heat transfer plates 40 having a supply port 41 and a discharge port 42 for heating medium, the plates being disposed alternately, liquids to be concentrated are passed through the supply port 31, then through the upper opening port of an upward preheating passage 34, and flows into a downward heating passage 35, where said liquids are dispersed, forming a thin film owing to an instantaneous increment in flowing speed thereof caused by vacuum flushing, and are concentrated in an increased rate of evaporation under conditions of non-circulation to be discharged from the discharge port 32 to the outside. Therefore, the liquids to be concentrated are completely prevented from such troubles as deterioration of constituents thereof and destruction of vitamins etc. due to heating by circulation. |
