Abstract: This investigation focused on the analysis of the cracks in the expansion joints for a chemical plant. It was found that the cracks formed because the allowable displacement was insufficient to relieve the thermal stress originating from the heat exchanger. In this regard,a new⁃type expansion joint was designed providing a fast and effective approach to solve the problems concerning the leaking of flammable and explosive gas. Based on the successful operation within 12 years,this expansion joint of new type was verified to be secure,economical and practical. Furthermore,with an expansion range exceeding that of the standard ones with the same specification,it can be used to replace the expansion joint with single wave,and applied in structures where the compensation is moderate.

Key words: Heat exchanger, Expansion joint, Cracks, Thermal stress, Compensation

摘要： 对某化工厂换热器膨胀节裂纹进行了重点分析，找出膨胀节产生裂纹的主要原因是设计膨胀节位移量不足以消除换热器温差应力。为此，设计了一种新型膨胀节，快速有效地解决了膨胀节裂纹泄漏易燃易爆气体带来的安全隐患。经过连续12年的正常运行，证明这种新型膨胀节的经济实用性和安全可靠性。另外，新型膨胀节的伸缩量远大于同规格的标准膨胀节，适用于替代失效的单波膨胀节，也可用于补偿量不太大的结构。

关键词: 换热器, 膨胀节, 裂纹, 温差应力, 补偿量