Improvements in or relating to rotary screening, sieving and sorting devices

摘要

438,636. Sifting - apparatus. HERRMAN, L., 33, Zwickauerstrasse, Dresden, Germany. Jan. 22, 1935, No. 2029. [Class 117] In rotary screens of drum form, the screening surface 1 is formed as a uniformly stepped cylinder and the complete surface including both the treads and risers of the steps are perforated. The treads may be flat or undulating, and the steps may be disposed about the cylinder in helical arrangement to promote the feed of the material through the screen. The nose of the treads and the foot of the risers may be rounded off, and the treads and risers may be of equal length and equally inclined to a radius of the cylinder. Reference has been directed by the Comptroller to Specification 248,541, [Class 117].