犁刀混合机动轴密封失效原因分析与研究

Analysis and study on the failure of the seal of the hybrid driving shaft of the plow blade

针对犁刀混合机工作介质为粉末物料时动轴密封失效问题,根据动轴密封试验结果及动轴密封原理展开失效原因分析。结果表明,密封气体出口压力大于工作介质压力、密封气体出口压力沿圆周方向均匀性、气密封通道宽度尺寸b沿圆周方向均匀性等3个条件,是保证犁刀混合机动轴密封性能的关键。在此基础上,再采用理论计算及有限元仿真相结合的方法对动轴密封失效原因展开进一步分析,根据分析结果分别从动轴密封设计、制造角度提出了犁刀混合机动轴密封失效的解决方法;最后通过试验验证了解决方法的正确性。试验结果表明,在动轴密封密封气体出口压力、配气环等设计符合要求的情况下,气密封通道宽度尺寸b沿圆周方向的偏心量为0.1 mm时,其连续密封时间分别是偏心量为0.3,0.6 mm时的3倍、13倍,即通过降低气密封通道宽度尺寸b沿圆周方向的偏心量,对提高动轴密封装置的密封性能有显著效果。研究成果对犁刀混合机动轴密封设计及应用具有一定指导意义。

In response to the failure of the dynamic shaft seal when the working medium of the plow blade mixer is powder material,the failure cause analysis is first carried out based on the results of the dynamic shaft seal test and the principle of the dynamic shaft seal.The analysis results indicate that:The outlet pressure of the sealing gas is greater than the working medium pressure;The outlet pressure of the sealing gas is uniform along the circumferential direction;The uniformity of the width dimension b along the circumferential direction of the airtight sealing channel is the key to ensuring the sealing performance of the plow blade mixer shaft.On this basis,a combination of theoretical calculation and finite element simulation was used to further analyze the reasons for the failure of the dynamic shaft seal.Based on the analysis results,solutions for the failure of the plow blade hybrid dynamic shaft seal were proposed from the perspectives of the design and manufacturing of the driven shaft seal;Finally,the correctness of the solution was verified through experiments.The experimental results showed that,under the condition that the gas outlet pressure of the dynamic shaft seal and the design of the gas distribution ring meet the requirements,the continuous sealing time of the gas seal channel width dimension b with an eccentricity of 0.1 mm along the circumferential direction is 3 times and 13 times that of the eccentricity of 0.3 mm and 0.6 mm,respectively,Reducing the eccentricity of the width dimension b of the gas sealing channel along the circumferential direction has a significant effect on improving the sealing performance of the dynamic shaft sealing device.The research results have certain guiding significance for the design and application of the seal for the hybrid shaft of plow blades.