Innovative solution for repairing and increasing the operational safety of rotary drum mill spindles

Abstract

The paper present a welding repair technology for bottom of the mill as well as a constructive solution for increasing the safety in their operation. The article is structured on two main directions, a technological one - the spindle repair and the other with finite elements for increasing the safety in operation. In the first part are presented the problems related to the occurrence of defects during the operation of rotary. Most defects are: geometrical deformations, cracks, metal cracks, followed by damage. It is presented how to repair by welding the mill by removing the metal cracked area and mounting a compensating ring. To minimize deformations, a on centering device, for flange + ring + cylinder was designed and built. In the second part, using finite element programs, are present the result of the mechanical stresses of the used spindle and a new constructive variant that ensures an increased safety in operation. With the help of the finite element analysis software, the geometric shape and the degree of stress was optimized. From the calculations a decrease of up to 50% of the geometrical deformations occurred and a decrease of up to 70% of the stresses in the requested area.