Expanded application of lens gasket seals In underwater sealing, while considering the internal pressure, it is also necessary to consider the external pressure that increases with the depth of the water. Compound lens gasket gaskets came into being. It is added to the standard lens gasket of the main body for resistance to external pressure. Pressed non-metallic sealing ring, the specific structure has the following two forms. Axial composite sealing ring, as shown in Figure 6. Axial refers to the introduction of an O-ring axial seal. For the axial composite sealing ring as shown in Figure 6, the upper and lower end faces of the protruding flange are machined with annular grooves, and an O-shaped non-metallic gasket is built in to form a secondary seal in the axial direction of the outer side. This composite sealing ring has very strict requirements on the sealing preload, because the sealing performance is mainly determined by the initial precompression, which in turn depends on the axial sealing preload. During the working process, the compression amount of the metal lens pad and the non-metal O-ring is required to meet the sealing requirements at the same time, and the O-ring cannot be compressed and damaged. Radial composite sealing ring refers to the formation of a secondary non-metallic radial seal between the O-ring and the mating end face, as shown in Figure 7. This seal increases the outer diameter of a standard lens pad without changing the inner diameter and spherical dimensions. This structure has strict requirements on the assembly of the sealing ring, because the compression amount of the O-ring cannot be changed after the assembly is completed, so the sealing capacity is also determined. Typical applications of these two composite seals are shown in Figures 8 and 9. Conclusion According to the working characteristics of high temperature and high pressure in deepwater pipelines, the parameter size of the 18-inch metal lens type sealing ring is designed, and the finite element analysis is carried out to explore the distribution law of working stress. The results verify the correctness of the structural design. The compound lens sealing ring is obtained by expanding the application of the sealing ring, which has the sealing ability of the standard metal lens pad under the same conditions and takes into account the sealing performance of the external pressure, and is especially suitable for the special underwater environment. References [1] MSS SP-65-1994. High Pressure Chemical Flanges and Threaded Stubs with Lens Gaskets [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 through NPS 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). The influencing factors of bearing radial clearance are multi-faceted. The main factors affecting 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 cylindrical roller bearing models in high-speed trains. Of course, the working conditions of rolling bearings are very complicated. In addition to the above-mentioned main reasons, 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 crown cylindrical roller bearing structure is adopted to avoid the boundary stress concentration at both ends of the roller. This design is more conducive to the uniform bearing load under high power and high speed conditions, and can make the cylindrical roller bearing in the most good working condition. References [1] Ge Zailin, Dong Meiyun, Zhang Xiujuan. Force Analysis of Cylindrical Deep Hole Roller in Cylindrical Roller Bearings［J］． Mechanical Design, 2003 (7): 59-60. [2] Liu Zejiu. Rolling Bearing Application Manual [M]. Beijing: Machinery Industry Press, 2007: 106-119. [3] Wan Suwen, Sun Shaodong, Cao Haijun. Centrifugal deep hole cylindrical roller bearing device and design of elastohydrodynamic lubrication［J］． Mining Machinery, 2012 (1): 118-121.4] Wang Yongxin. Engineering Tribology [M]. Hangzhou: Zhejiang University Press, 1994: 324-354. [5] Mechanical Engineering Handbook Editorial Board of Electrical Engineering Handbook. Mechanical Engineering Handbook [M]. Second Edition. Beijing: Machinery Industry Press, 1996. [6] Wan Suwen, Jiang Yanan. Cylindrical roller bearing device and lubrication design in NGW planetary gear transmission［J］． Coal Mining 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 radial working clearance of cylindrical roller bearings［J］． Bearings, 2005 (8): 8-10. [9] Wang Zhenhua. Practical Bearing Handbook [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 in high-speed trains［J］． Railway Vehicles, 2001 (4): 5-6.