Research On Vertical Settling Centrifuge With Screw Precipitate Discharge

Centrifuge is one of the essential equipment in separation industry. For the requirement of recovering carborundum particles from the solid-liquid mixture, and solving the problems ,such as large axial force and force moment existed in vertical centrifuge, some research on the vertical settling centrifuge with screw precipitate discharge is done in this paper, which has great significance in engineering application field.Firstly, the basic working principle of the centrifuge is found out, and the important technical parameters are fixed on primary based on experience, and then, the rotor bowl, screw conveyor and other parts are designed on Pro/E platform and assembled to integer according to overall arrangement and scheme.Secondly, in order to minimize the axial force and force moment of the screw conveyor, a mathematical model for the multi-objective optimization is established, which considers minimizing the force moment and axial force as well as maximizing the efficiency of precipitate discharge, then it is solved on Mathematica and MATLAB platform. After that, the work of comparing the results from optimization and other calculations on special points are finished, the results show that the theoretic axial force and force moment are reduced remarkably.Thirdly, the stress and displacement of the important parts are analysised using software ANSYS in this paper. Because of the eccentricity consisted in screw conveyor entity, aberration appears in its Finite Element (FE) model, a strategy of resetting the place of the screw vane to reduce the imbalance is present in the paper; Furthermore, for the sake of finding the relationship between maximal stress (SINT) and the thickness of rotor bowl, a series of bowl FE model is built and solved; After FE analyzing, checking up the throughput of the sample and calculating the power which provide data for choosing the motor are finished.Finally, the control system that is composed of PC and PLC is described in the last section of the paper. PC software provides man-machine interface, and performs speed setting and displaying; PLC takes charge of controlling and adjusting speed. The communiation between PC and PLC use RS-232 interface, and every frame of data is verified with FCS code to make sure the correctness of the massage; In addition, finite state machine(FSM) methodology is introduced in the stack programme. Communication protocol stack is divided into a lot of states and actions, so that, it can simulate FSM. The test show that FSM makes the software work reliably and stability.