| Decanter centrifuge is widely used centrifugal separation equipment with continuous operation, high efficiency, high degree of automation, large capacity, low power consumption and strong adaptability. Screw conveyor is the main component of decanter centrifuge, its structure and parameters decide not only the effectiveness of centrifuging process, but also the lifespan of the whole machine.In this dissertation, the capacity of a certain kind of centrifuge is calculated, and based on the mass conservation law, the yield of wet sediment is estimated. Furthermore, mechanical analysis is carried out for the sediment during the normal operation of the conveyor.Three dimensional finite element model of screw conveyor was created with parametric programming language APDL of the software ANSYS, and mesh density was tested for the accuracy the modeling. Stress and deformation of screw conveyor under normal operation conditions were analyzed.Influence of opening of the feeding hole on the strength of the inner tube was investigated. Results show that although a long opening raises the stress in the conveyor, a long and narrow circumferential feeding inlet could be allowed in the precondition of ensuring feed rate and causing no jam. Increasing the thickness of the inner tube could decrease the maximum stress intensity in the whole conveyor, but the maximum stress intensity in the blade could decrease first and then increase.Referring to the analysis design code for pressure vessel, strength check was carried out for the screw conveyor under normal working condition and it turns out that all the strength requirements are satisfied.Mode analysis was also performed for the.screw conveyor and it is found that under normal operation, resonant vibration will not happen. Besides, natural frequencies under different stiffness, locations and the thickness of the inner tube were calculated, which could be helpful for design and structural optimization of the conveyor.
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