Multistage molecular evaporator with wiped off film and continuous redistillation

Claim 1

A liquid seal for a multistage molecular evaporator having an evaporator vessel with a convex evaporating surface adapted to carry out a continuous redistillation, comprising in combination, a first vacuum stage having a first cylindrical portion surrounding the evaporating surface, a second vacuum stage having a second cylindrical portion mounted below said first stage; an inwardly projecting first trough mounted on said first cylindrical portion and adapted to collect distillate formed therein, an overflow tube extending from said first trough downwardly into said second stage; an overflow collecting and separating means mounted in said second stage below said overflow tube and adapted to receive distillate from the first vacuum stage; said inwardly projecting first trough, overflow tube and overflow collecting and separating means forming a first liquid seal; an inwardly projecting second trough mounted on said first cylindrical portion below said first trough; a member mounted in said first stage and extending into said second trough, said member adapted to collect distilland from said first stage and conduct it into said second trough; said second trough and member extending therein adapted to form a second liquid seal; said first and second stages having evaporator means; and sealing ring means disposed between the evaporator means of said first and second stages to sealingly connect them to each other.