某型安全活门低温漏气故障分析和改进

为解决某型飞机高空飞行后座舱盖气动系统内存储的氨气大量泄漏的问题,通过对该系统的减压器组件返修件开展工作环境模拟试验,确定故障原因为某型安全活门在低温条件下异常开启,进而对该型安全活门的产品结构原理、零件受力状态和低温环境影响进行分析研究。论证了安全活门壳体尺寸控制不当、弹簧预紧力偏大、安全活门内部间隙过小,在低温作用下活门橡胶面收缩并脱离阀口是导致泄漏的根本原因。提出了在产品维修过程中,采取合理控制壳体的装配尺寸及活门内部间隙,并通过带压低温试验来模拟实际工作条件验证产品工作性能的措施,能够有效降低同类故障的发生率。

Analysis and Improvement of a Certain Type of SafetyValve Leakage in Low-temperature

To solve the problem of a large amount of nitrogen leakage stored in the pneumatic sys.tem of the cockpit cover of a certain type of aircraft after high altitude flight, carried out the workingenyironment simulation test on the repair parts of the pressure reducer assembly of the system, anddetermined that the cause of the failure was the abnormal opening of a certain type of safety valveunder low temperature conditions. Then , the product structure principle, the stress state of the partsand the influence of the low temperature environment of the safety valve were analyzed and studiedIt was demonstrated that the improper control of the safety valve shell size, the large spring preloadthe too small internal clearance of the safety valve, and the shrinkage of the valve rubber surface andthe detachment from the valve port under low temperature were the root causes of the leakage. In theprocess of product maintenance , the measures of reasonably controlling the assembly size of the shelland the internal clearance of the valve and simulating the actual working conditions to verify theworking performance of the product through the pressure low temperature test can effectively reducethe incidence of similar faults.