GB610298A - Improved apparatus for sifting materials - Google Patents

Abstract

610,298. Sifting-apparatus. BROOKE, BOND, & CO., Ltd., and COOKE, W. M. April 9, 1946, No. 10870. [Class 117] A vibrating motion is imparted to a perforated sifting drum 5 which contains granular material such as tea, by mounting the shaft 4 of the drum eccentrically in a sleeve 3 and rotating the sleeve relatively to the shaft. Preferably both the drum and shaft are rotated but at different speeds. As shown, the shaft 4 extends outwardly from one end wall 5b of the drum, the other end of the drum being open for introducing the material into the drum. The shaft is inclined so that it is eccentric to the sleeve at the drum end but is concentric at the opposite end. The drum is somewhat downwardly inclined so that the larger pieces of material which do not pass through the perforated cylindrical wall travel towards, and are discharged through, the open end. The sifting perforated surface 5a may be constituted by a sheet of gauze releasably secured upon the drum structure, e.g. by means of spring strips 14a each having a loop at one end engaging a crank pin 15 on the end disc 5b and a hook 14b at the opposite end to hook on to the front end ring 5c of the drum. The ends of the perforated sheet may overlap in a shallow longitudinal trough formed in the outer surface of one of the stays 13 and be secured by a strip 14a. In the case of tea sifting the end wall 5b of the drum carries within the main drum 5 so as to be rotatable therewith a smaller diameter perforated drum 16 for use in breaking up moist rolled green leaf.