Research On Reliability Design And Analysis Technology Of Ring Mold Granulator

Pellet mill, characterized by high effectiveness and excellent forming effect, is the main equipment to produce pellet feed and biomass pellet fuel. With the ever increasing demand of pellet feed and biomass pellet fuel, the market demand of pellet mill is also growing. Based on the fact that the reliability of domestic pelleting equipment is bad, the research on the reliability design and reliability analysis of pellet mill is conducted in this paper. The aim of the research is to make some references for the optimal design and reliability growth of pellet mill. The main work accomplished is as follows:(1) The reliability index of a certain type of pellet mill is assessed based on failure data. Then the distribution pattern of the time between failure is confirmed and several reliability indexes of pellet mill are deduced and computed according to it, providing basis for the analysis of dynamic reliability of pellet mill.(2) The critical subsystems are ascertained and the Failure Mode Effect and Criticality Analysis (FMCEA) of critical subsystems is conducted. Some measures are proposed to guarantee and improve the reliability of pellet mill in accord with the analysis results.(3) The existing reliability allocation method-the fuzzy analytical hierarchy process (FAHP) is improved and the improved FAHP is applied to the reliability allocation of pellet mill and pelleting subsystem.(4) The reliability model of the core component-ring die is built and the fatigue life reliability and wear reliability are predicted respectively, then the reliability of ring die is analyzed synthetically.(5) The design scheme of the existing ring die is modified and two new types of ring dies are proposed. Then the reliability analysis of the two ring dies newly proposed is conducted. The result shows that not only the life distribution at the junction of flange and the outer wall of the ring die whose cross angle of hole is 60°is improved, but the reliability of this ring die is improved. This work can provide reference for the structural improvement and reliability growth of ring die.