VELAN气动阀典型故障分析及处理措施研究

某核电厂工程安装调试期间，VELAN气动阀出现阀瓣开裂和气动头漏气的典型故障。经分析可知阀瓣开裂的根本原因为阀瓣制造过程中存在焊接质量缺陷，导致脆性增高，加之阀门在使用过程中受到过载应力作用，发生脆性开裂。处理措施为更换阀瓣组件和填料，并进行密封性试验。气动头漏气根本原因为O环尺寸存在偏差，压缩量不足导致漏气，处理措施为增大气动杆中心螺母力矩，进行力矩紧固，紧固完成后再次进行密封试验，或测量补偿环的厚度以及O环尺寸并进行处理，如更换补偿环或O环。通过以上措施，VELAN气动阀典型故障得到有效处理，对后续类似问题的分析及处理提供了参考和借鉴。 

Analysis of Typical Faults and Treatment Measures of VELAN Pneumatic Valve

The VELAN pneumatic valve experienced typical faults such as valve disc cracked and air leakage from the pneumatic head,?during the installation and commissioning of the nuclear power plant project. In-depth analysis and research in this paper show that the root cause of valve disc cracked is the welding quality defect in the valve disc manufacturing process, resulting in increased brittleness, and the valve is subjected to overload stress during use, resulting in brittle cracking, and the treatment is to replace the valve disc assembly and packing, and to conduct a leak test. The root cause of leakage of the pneumatic head is that there is a deviation in the size of the O-ring, and insufficient compression causes leakage, the treatment is to increase the torque of the pneumatic rod center nut, tighten the torque, and then perform the sealing test again after the fastening is completed, or measure the thickness of the compensation ring and the size of the O-ring and process it, such as replacing the compensation ring or O-ring. Through the measures, the typical faults of VELAN pneumatic valves are effectively processed, which provides a reference for the analysis and treatment of similar problems in the future.