Numerical and experimental analysis of the reusability of spring energized metal C rings

• Published in: Science China. Technological sciences 2014-08, Vol.57 (8), p.1670-1676
• Main Authors: Liu, Ying, Zhou, Kun, Huang, WeiFeng, Gao, Zhi, Wang, YuMing
• Format: Article
• Language: English
• Subjects: Activation; Coating; Contact; Elastic modulus; Engineering; Seals; Springs; Springs (elastic); Wall thickness; 可重用性; 实验分析; 弹性模量; 数值; 法向力; 装配过盈量; 金属环; 非线性有限元法
• ISSN: 1674-7321; 1869-1900
• DOI: 10.1007/s11431-014-5584-3

It is well known that static seals are usually designed to be used once. In this paper, we discuss the reusability of a type of static seal called the spring energized metal C ring, which is required to be reused 4-5 times without maintenance during the lifetime of the pump. A theoretical analysis based on the nonlinear finite element method and an experimental investigation of the reusability of the C ring are carried out. The effects of the elastic modulus of the ring material, the ring wall thickness, the amount of assembly interference between the spring and the C ring, the operating temperature and the compression ratio are discussed. The parameter S, which denotes the reaction force difference percentage, is determined to measure the reusability of the C ring. The results show that the ring wall thickness plays an important role in the reusability. Although the normal force of a thick wall decreases after the ring is reused eight times, the value is still higher than the first normal force of a thin wall. In contrast, the elastic modulus of the material has the lowest impact. Here, a pre-compression ratio of 18.2% not only produces a larger first normal force but also leads to a smaller reduction in the normal force when the ring is reused. A simulated experiment is carried out to investigate the influence of the coating of the C ring on its reusability. The results show that when plastic deformation occurs on the contact surface, the contact state of the C ring coating becomes a major factor that affects the seal performance. Aging treatment at high temperatures （250℃） reduces gized metal C ring, which leads to the deterioration in the reusability the binding force of the silver coating on the spring ener of the ring.