Examination of operation of spiral classifier 2KCN-30 manufactured by Catoca Mining Company Ltd., Angola, revealed insufficient durability of feed–nut assembly. Aiming to enhance service reliability of spiral drive, it was proposed to modernize the drive by replacing the feed–nut assembly by a later ball-and-screw unit. At the same time, to reduce the upgrading cost of the lifting mechanism in the spiral classifer, it was decided to utilize to the maximum practicable extent the existing design of the basic parts of the mechanism. The structural analysis of the feed–nut assembly with the feed made of steel 35 and nut made of bronze BrO6TsbS3 showed that the lifting mechanism had a low efficiency of not higher than 0.2. Furthermore, the operation of the feed–nut assembly revealed low service reliability of the bronze nut. Reengineering of the lifting mechanism with the conversion of rotational motion of a nut to translational motion of a crew by means of a ball-and-screw unit assumed some source data: single-thread assembly with a clearance, driver was a nut, required life of 1 million cycles, failure-free operation probability 90%. The calculations have shown that as compared with the current design of the drive with the feed–nut assembly, the ball-and-screw unit enhances the drive efficiency more than 3 times, which allows 3 times reduction in energy consumption.


Spiral classifier, spiral lifting mechanism drive, feed–nut assembly, ball-and-screw unit.

Issue number: 2
Year: 2018
UDK: 669.2
DOI: 10.25018/0236-1493-2018-2-0-215-221
Authors: Gorbatyuk S. M., Zarapin A. Yu., Chichenev N. A.

About authors: Gorbatyuk S.M., Doctor of Technical Sciences, Professor, Head of Chair, e-mail:, Zarapin A.Yu., Doctor of Technical Sciences, Professor, e-mail:, Chichenev N.A., Doctor of Technical Sciences, Professor, e-mail:, National University of Science and Technology «MISiS», 119049, Moscow, Russia.


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