Multistage molecular evaporator with wiped off film and continuous redistillation

摘要

A liquid seal for a multistage molecular evaporator which is in the form of an elongated vessel having convex evaporating surfaces for carrying out a continuous redistillation. The evaporator includes at least two vacuum stages superposed one over the other in the vessel. The upper stage has two inwardly extending troughs one superposed over the other. An overflow tube extends from the upper trough into a collecting trough of the adjacent lower vacuum stage to form a first liquid seal. A collecting member in the upper stage extends into the lower trough of the upper stage to collect distillate therein and to form a second liquid seal therein. The upper and lower vacuum stages have evaporator bodies which are connected to each other by sealing means.