介绍了长输管线的排污与放空在管线工程中的作用和实际应用效果,分析了管线阀门排污与放空在实际工程中的必要性及排污与放空对活塞效应阀座的影响,提出了管线阀门活塞效应阀座的设计必须与排污、放空有效结合,管线阀门才能实现双截断与泄放的功能。 This paper introduces the function and practical application of sewage and venting of long distance pipeline in pipeline project, analyzes the necessity of pipeline valve blowdown and venting in practical engineering and the influence of blowdown and blowdown on the piston effect valve seat, proposes the pipeline valve Piston effect design of the seat must be combined with the sewage, vent effective combination of pipeline valves to achieve double truncation and discharge function.