Objective There are challenges related to improving manufacturing and assembly accuracy to ensure adequate sealing performance. The sealing device of the plow blade hybrid motor shaft, which primarily relies on gas sealing, exhibits low sealing performance and a short service life. Methods This study proposed enhancing manufacturing and assembly accuracy and improving sealing performance. A new design concept and scheme for the plow blade mixing dynamic shaft sealing device were developed by applying the spiral conveying principle and integrating various forms of sealing in the powder medium dynamic shaft sealing device by combining the sealing structure and principles of the plow blade mixing dynamic shaft. Based on the theoretical calculation of the maximum leakage speed of the 2 000 L plow blade mixer material, the design objective aimed to ensure that the conveying speed of the spiral seal for the leaked material exceeded the material's maximum leakage speed, determining the design values of the main parameters of the spiral seal. Then, the theoretical maximum material accumulation in the gap between the spiral seal and the inner wall of the sealing seat was derived from the main parameter design values of the spiral seal. This maximum theoretical material accumulation served as the foundation for ensuring that the volume flow of the sealing gas after passing through the labyrinth seal surpassed the theoretical maximum material accumulation. Therefore, the main design values of the labyrinth seal were obtained. Thereafter, SolidWorks Flow Simulation software was employed to preliminarily verify the design results of the labyrinth seal and to assess whether the volume flow rate of the sealing gas after traversing the labyrinth seal exceeded the theoretical maximum material accumulation. The simulation outcomes confirmed that the labyrinth seal design satisfied the design criteria. Then, experimental research methods were utilized to determine whether the actual residual amount of material in the sealing seat of the dynamic shaft sealing device was less than or equal to the theoretical maximum accumulation amount when the sealing gas was not introduced, and whether the actual sealing gas volume flow rate after labyrinth sealing surpassed the actual residual material amount. Results and discussions The results revealed that 1) the continuous sealing time of the new dynamic shaft sealing device was 120 hours, nearly doubling the continuous sealing time of the existing dynamic shaft sealing device; 2) by employing spiral conveying and introducing sealing gas through the labyrinth seal, most of the leaked materials to the primary seal were promptly transported or cleaned back into the chamber, reducing friction and wear between the seal and powder materials, enhancing the dynamic shaft device's sealing performance, ensuring the seal's service life, and avoiding the high manufacturing and assembly accuracy requirements of the dynamic shaft sealing device that used gas seal as the primary seal; and 3) compared to the current dynamic shaft sealing device, the newly designed dynamic shaft sealing device exhibited reliable sealing performance, lower manufacturing costs, and easier installation and maintenance, meeting the sealing performance and service life requirements of the plow blade mixer for the dynamic shaft sealing device. Conclusions At present, this novel plow blade hybrid motor shaft sealing device has been successfully applied to the production equipment of multiple lithium battery material and military enterprises. It has also been extended to various types of powder material production equipment, receiving substantial customer recognition. The research findings provide valuable insights for improving the sealing performance of the plow blade hybrid dynamic shaft and for advancing the application of dynamic shaft sealing across multiple types of powder media.
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