The extended application of lens gasket seals. Underwater seals need to consider internal pressure and external pressure that increases with the depth of the water. A composite lens gasket seal comes into being, which adds resistance to external pressure on the standard lens gasket of the main body. The specific structure of the pressed non-metallic sealing ring has the following two forms. Axial composite sealing ring, as shown in Figure 6. Axial refers to the introduction of O-rings for axial sealing. For the axial composite seal ring shown in Figure 6, the upper and lower end faces of the protruding flange are machined with annular grooves, and O-shaped non-metallic gaskets are built-in to form a secondary seal in the outer axial direction. This kind of composite sealing ring has very strict requirements for the sealing pre-tightening force, because the sealing performance is mainly determined by the initial pre-compression amount, and the pre-compression amount depends on the size of the axial sealing pre-tightening force. In the working process, the compression of the metal lens pad and the non-metal O-ring are required to meet the sealing requirements at the same time, and the O-ring cannot be compressed and damaged. The radial compound seal ring refers to the secondary non-metallic radial seal formed between the O-ring and the mating end face, as shown in Figure 7. The sealing ring enlarges the outer diameter of the standard lens pad without changing the inner diameter and spherical size. This structure has very strict requirements for the assembly of the sealing ring, because the compression of the O-ring cannot be changed after the assembly is completed, so the sealing ability is also determined. The typical applications of these two composite seal rings are shown in Figure 8 and Figure 9. Conclusion According to the working characteristics of high temperature and high pressure of deepwater pipeline, the parameter size of 18-inch metal lens seal ring is designed, and the finite element analysis is carried out to explore the distribution law of working stress. The result verifies the correctness of the structural design. By expanding the application of the sealing ring, a composite lens sealing ring is obtained, which has the sealing ability of the standard metal lens gasket under the same conditions and takes into account the sealing performance of external pressure, which is especially suitable for special underwater environments. References [1] MSS SP-65-1994. High pressure chemical flange and threaded short pipe with lens pad [S]. [2] DIN2696-1999, Lenticular Ring Joint Gaskets for Flanged Joints [S]. [3] ASME B16.5-2009, Pipe Flanges and Flanged Fittings NPS 1/2 throughNPS 24 Metric/Inch Standard［S］.［4］API 6A-2004, Specification for Wellhead and Christmas Tree Equipment［S］.［5］ASME Boiler u0026 Pressure Vessel Code VIII Division 2-2007, Rules for Construction of Pressure Vessels［S］.［6］West Alan, Giles John, Gibson David.Diver less subsea flange connection［J］. Journal of Offshore Technology, 1999, 7(1) ： 2-5. [7] A. Kaplan, M. Mizutani, S. Katayama, et al. Analysis of different methods for the prevention of pore formation in keyhole laser spot welding［J］.Welding in the World, 2002, 46( 7): 39-50. [8] Hirohiko A, Susumu T. Position control of a manipulator with passive joints using dynamic coupling［J］． IEEE Transaction On Robotics and Automation, 1991 (8). There are many factors influencing the radial clearance of a bearing. The main factors affecting the radial clearance are quantitatively considered, and qualitative analysis and quantitative calculation are carried out. Compared with the traditional analysis method, this method can improve the reliability of the cylindrical roller bearing in the high-speed train. Of course, the working conditions of rolling bearings are very complicated. In addition to the main reasons mentioned above, there are other factors, such as lubricating oil, the quality of the bearing itself and the bearing assembly structure, etc., which need to be further studied. At the same time, the deep hole logarithmic convexity cylindrical roller bearing structure avoids the boundary stress concentration at the two ends of the roller. This design is more conducive to uniform bearing load under high-power and high-speed working conditions, and can make the cylindrical roller bearing at its maximum Good working condition. References [1] Ge Zailin, Dong Meiyun, Zhang Xiujuan. Force analysis of cylindrical deep hole roller of cylindrical roller bearing［J］． Mechanical Design, 2003 (7): 59-60. [2] Liu Zejiu. Rolling bearing application manual [M]. Beijing: Mechanical Industry Press, 2007: 106-119. [3] Wan Suwen, Sun Shaodong, Cao Haijun. Centrifugal deep hole cylindrical roller bearing device and elastohydrodynamic lubrication design［J］. Mining Machinery, 2012 (1): 118-121.4] Wang Yongxin. Engineering Tribology［M］. Hangzhou: Zhejiang University Press, 1994:324-354. [5] Mechanical Engineering Handbook, Electrical Engineering Handbook Editorial Committee. Mechanical Engineering Handbook [M]. 2nd Edition. Beijing: Mechanical Industry Press, 1996. [6] Wan Suwen, Jiang Yanan. Cylindrical roller bearing device and lubrication design in NGW planetary gear transmission［J］． Coal Mine Machinery, 2012 (3): 80-82. [7] Shi Ying, Li Baoliang. Numerical simulation of cylindrical roller bearing wear［J］. Lubrication and Sealing, 2009 (11): 23-26. [8] Guo Pancheng. Influencing factors and selection of cylindrical roller bearing radial working clearance［J］． Bearing, 2005 (8): 8-10. [9] Wang Zhenhua. Practical Bearing Manual [M]. Second edition. Shanghai: Shanghai Science and Technology Literature Publishing House, 1996. [10] Sun Junqiang. Analysis of the fit and original radial clearance of cylindrical rolling bearings of high-speed train［J］. Railway vehicles, 2001 (4): 5-6.