Influence of centrifuge failures of parallel cascade

A centrifuge cascade is composed of a large number of centrifuges connected in parallel or/and in series, and a parallel-connected cascade is an important form of cascades. Rotor damage and other causes may lead to centrifuge failures, which are inevitable during the cascade operation, result in the changes of the fluid parameters, product abundance and flow rate, and affect the separation performance. A cascade operates continuously for a long-time, and the failed centrifuges are not replaced or repaired once it is put into operation. As the operation time increases, the number of failed centrifuges would gradually increase. Assuming the number of failed centrifuges obeys a Poisson distribution, and taking a 2-layer cascade as an example, the influence of centrifuge failures on fluid parameters and separation performance is studied in this paper. It is found that centrifuge failures lead to a decrease in the product flow, changes in the concentrations of product flow and waste flow, and a deterioration in the cascade separation efficiency while maintaining the feed flow constant. The degree of the influence of centrifuge failures on the parallel-connected cascade depends on the locations of failed centrifuges, the failure probability of a centrifuge, operation time as well as other factors. Occurrence of centrifuge failures in some stages may have a significant influence on the fluid parameters and separation performance. In order to know which stage has the most significant impact on the cascade, the changes in the fluid parameters and separation performance caused by failed centrifuges should be evaluated before the installation and operation of a cascade. (authors)