Soln. concentrating appts. in continuous process - comprising vessel to recrystallise solvent and units combining crystal sepn. and wash-out

摘要

Appts. comprises a closed re-crystallisation vessel which is fed via a cooled and scraped pre-crystallisation unit and contains a stirrer. The vessel has one or more outlets on the top leading to crystal separators each comprising a vertical cylinder contg. a movable sieve element which compacts the crystals against the underside of the column of crystals being formed in the cylinder. This column is thereby moved upwards towards a rotatably driven scraper in the closed upper end of the cylinder where the crystals at the top of the column are successively removed via an outlet by washing-out liq. admitted via an inlet. Concentrating soln. by crystallising the solvent and removing crystals in separators with wash-out liq. supply. The arrangement combines sepn. with wash-out and permits continuous operation by using a number of, possibly standard-size, separators on one vessel.