Study On Failure And Wear Mechanism Of Screws And Berrel Of Twin-Screw Pulping Extruder And Design On Special Coupling

Twin screw pulping extruder is a new kind of energy-saving pulping machine, and it has a good characteristic and broad application. Pulping system is one of the key parts of twin screw pulping extruder, but in performance test run easy wreckage the core of the screw, quick wear between screw and machine barrel lead to failure and suspend production for repairing of twin screw pulping extruder, which causes the rising cost of the pulping. Therefore it is necessary to study the failure and wear mechanism of screws and barrel of Twin Screw Pulping Extruder in order to improve the reliability and prolong service life.The paper briefly describes the development of twin screw pulping extruders and problems existed in pulping system, expounds wear mechanism of screws and barrel, then discusses the research status about wear on screw and barrel of twin screw pulping extruder and plate of disc refiner and methods to reduce wear. Also through these methods, the new design methods on reducing broken shaft and wear failure based on actual design requirement of Twin Screw Pulping Extruder are proposed.The reason of the broken shaft on screw and the wear mechanism of the screw and barrel of Twin Screw Pulping Extruder were analyzed theoretically, computer simulation and finite element analysis of screw mandrel stress are analyzed by software of ANSYS. The main reason of the broken shaft on screw and the wear between the screw and barrel of Twin Screw Pulping Extruder can be gotten by analysis, and the measures of avoid broken shaft and reduce wear of screw and barrel are propound.Refer to the select of relevance mechanical equipment coupling, according to the large torque and restricted center distance of Large Twin Screw Pulping Extruder, we design the crown gear coupling of high torque considering radial restriction, and discuss the effects of tooth width on tooth form and machining.Considering the condition of contact characteristic, we have nonlinear static finite element analysis for crown gear coupling meshes and bolt connection by ANSYS software. The results showed that the contact stress intensity of crown gear meets the requirement. The effective ways to ensure the bolt connection intensity is choosing high-strength bolt and nut and increasing the friction coefficient between both sides of the flange surface.The paper has studied the broken shaft of the screw and wear mechanism of screw and barrel of twin screw pulping extruder, the design and option on special coupling applied for large twin screw pulping extruder are studied, the parameters design and finite element analysis for the crown gear coupling of big torque considering radial Restriction are studied also. This work has great significance for improve design and reliability, and the increase of service life of the Twin Screw Pulping Extruder.