Abstract:

This paper introduces the main parameters and difficultiesin the research of NPS24 Class 900 high pressure large diameter bidirectional seal program-controlled risingstem ball valve.Tosolve the problems in traditional rising stem ball valvesuch as the inability to meet bidirectional sealing requirements,the lower support shaft strain, andthe difficulty in valve seat maintenance, the designofvalve structureis optimized.In order to ensure the integrity of the pressure boundary, ASME B16.34 and finite element methodare used to calculate and analyze the strength of valve body and valve cover. The results show that the structure of the valve body and valve coveris safe. The calculation of torsion angle and torsional stiffness at the spiral track groove of valve stem shows that the strength of the valve stem is safe. By optimizing the casting process of LC1 material, the low-temperature impact toughness of LC1 materialissignificantly improved,meeting thespecial requirement of -52 ℃ low-temperature impact value ≥ 27J.The valve stem processing technologyis optimized to meet the frequent action requirement of 750 times per year. The sealing surface of high pressure large diameter sphere is sprayed using flame spraying melting technology, and the coating and substrate are metallurgical structures, effectively improving the wear resistance and erosion resistance of the high pressure large diameter sphere.The results of the bidirectional high pressure liquid sealing test, bidirectional high pressure gas sealing test and bidirectional low pressure gas sealing test of the valve all meet the requirements of GOST 9544 Class A.During the no-load operation test and maximum closing differential pressure operation test of the valve, the valve opens and closes smoothly without any jamming, sticking, crawling or shaking. Thecomprehensive performance test results indicate that the localization development is successful.

Key words:

high pressure, large diameter, bidirectional seal, program-controlled, risingstem ball valve ')">"> high pressure, large diameter, bidirectional seal, program-controlled, risingstem ball valve