Study On Strength Design Methods Of Large-scale Pulping Roller

Twin roll wash press is one of the most popular machines in black liquor extracting and stock thickening all cross the world.The pulping roller is the most important part in the twin roll wash press,used to accomplish the function of filtration,washing and press.The design of the small and medium-sized pulping roller was based on the method of experience,hadn't scientific strength design method.With the increase of the requirement in paper industry,the large twin roll wash press began to show up.With the sharply increase of the dimension and load,the original method of experience can't meet the security demand of the pulping roller in the working.In this paper,firstly,we established mechanical model of pulping roller based on the structure and working condition,analyzed the stress status under the biggest static force,designed engineering static strength algorithm using distortion energy theory.And based on the static strength algorithm and fatigue circulation characteristics,considering the factors affecting fatigue strength,using allowable stress method and safety factor method,we designed pulping roller's fatigue strength.Based on the engineering static strength algorithm and fatigue strength algorithm,we designed the strength check program of pulping roller by visual basic language.Meanwhile,we analyzed the pulping roll's static strength by establishing the whole pulping roll's finite element model using the finite element analyze software ANSYS Workbench,and made a comparison with the static strength algorithm.These two methods had the same calculation result,so proved the effectiveness of the static strength algorithm.Based on the finite element static strength analysis and fatigue circulation characteristics,by selecting and correcting all the part's S-N Curve,and setting the ANSYS Fatigue module,we solved pulping roller's fatigue strength safety factors,and made a comparison with the fatigue strength algorithm.These two methods had the same calculation result,so proved the effectiveness of the fatigue strength algorithm.Otherwise,the interference of the partition-support device and the screen-support device has a great influence to the connector strength,and different from the general interference calculation method,they are all multistage interference fit.In this paper we used the finite element analyze software ANSYS Workbench,analyzed how the interference of the partition-support device and the screen-support device influences the pulping roller's local strength and the relation with the torque it can pass through establishing the different interference finite element model.Meanwhile,we also considered the temperature's influence to the interference.In the end,we got the interference design range which can meet the strength and torque demand,so provided practical method for interference design of the partition-support device and the screen-support device.