PROCESS FOR SCREENING CELLULOSE ETHERS

摘要

A process and apparatus for screening cellulose ethers which have a finely fibrous or wad-like or woolly structure, wherein the process comprises the following steps: a) applying the cellulose ether (material to be screened) to a sieve surface, b) dividing the material to be screened into an screenable portion (acceptable size material or material passing through the sieve) and a circulating portion (oversize material or sieve surface tailings) with the aid of an agitated (preferably vibrating and/or tumbling) sieve surface, c) flushing through the agitated sieve surface from below, generally perpendicularly to the sieve surface, with an air flow, d) discharging (recovering) the acceptable size material, and e) discharging the circulating portion from the sieving system. The air flow inhibits clogging or plugging of or matting upon the sieve surface and is preferably directed upward by slit nozzles arranged below the sieve surface.