大口径全焊接球阀双向密封性能研究

运输有毒或可燃性气体的管道泄漏易导致起火、爆炸等灾难性后果。大口径球阀常用于矿山通风或天然气集输管道，球阀的密封性能是设备安全稳定运行的关键指标。文章在高压密封和低压密封工况下对40英寸全焊接球阀的密封结构组件正、反向密封时的密封性能展开研究。结果表明:正、反向密封时，高应力区出现在阀座支撑圈上，最大等效应力小于屈服强度；阀座密封圈的高应力和最大变形均出现在与阀座支撑圈接触的2个尖角位置。高压密封时，阀座与球体接触区域的接触压力均大于介质压力，满足密封要求。相比于高压密封工况，低压密封时阀座与球体的接触区域明显减小，需确保介质工作压力大于设计压力，防止过低的介质压力降低其密封性能。该研究可为大口径球阀密封压力范围的确定提供参考，为大口径球阀双向密封性能分析提供研究方法。

Research on Two-way Sealing Performance of Fully Welded Large-caliber Ball Valve

The leakage of toxic or combustible gases can lead to catastrophic consequences. The large-caliber ball valves are often used in mine ventilation or natural gas gathering and transportation pipelines. Sealing performance of ball valve is a key indicator of safe and stable operation of equipment. In this paper, the sealing performance of the sealing structure components of the 40-inch fully welded ball valve under the high-pressure and low-pressure sealing conditions is studied. The results show that in the case of forward and reverse sealing, the high stress region appears on the valve seat support ring, and the maximum equivalent stress is less than the yield strength. Besides, the high stress and large deformation of the valve seat appear at the two sharp corners in contact with the valve seat support ring. In high-pressure sealing, the contact pressure between the valve seat and the ball contact area is greater than the work pressure to ensure sealing. Compared with high-pressure sealing conditions, the contact area between the valve seat and the ball is significantly reduced during low-pressure sealing. It is necessary to ensure that the work pressure is greater than the design pressure, because too low work pressure will reduce the sealing performance of the ball valve. This article provides a research method for analyzing the two-way sealing performance of large-diameter ball valves, and can provide a reference for determining the sealing pressure range of large-diameter ball valves.