The Serviced Straight Pipe Pressure Balanced Type Expansion Joint Life Assessment Technology Research

Expansion joint is a kind of elastic compensating element, it is mainly used for absorbing the heating and mechanical displacement of the pipelines and the equipment, and also used for absorbing vibration and reducing noise, etc. Due to the characteristics of the expansion joint, it is widely used in machinery, petroleum, chemical, elastic power, bridges and other industrial fields. Expansion joint is a structure element which has a service life, it will damage when it reach a certain working time. There are a lot of factors that can affect the life of the expansion joint, the life of the expansion joint should be evaluated at fixed periods in order to ensure the safety production. This article is mainly studying the life assessment technology and the life factors of the serviced straight pipe pressure balanced type expansion joint. There are several main findings as followed:(1) Assessed the life of the straight pipe pressure balanced type expansion joint, and then measured the deformation of the expansion joint bellows in cold and hot state conditions, checked the surfaces of the bellows and the supports of the expansion joint and the heat insulation diversion tubes, calculated and analyzed the stresses of the expansion joint bellows, it came up with a comprehensively life assessment technology route and concluded the residual service life of the straight pipe pressure balanced type expansion joint.(2) Conducted finite element Analysis based on the life assessment of the straight pipe pressure balanced type expansion joint, and the result showed that the theoretical calculation and the finite element simulation results were much closed, so it concluded that the assessment technology was feasible.(3) Discussed the factors that influenced the life of the expansion joint, and analyzed how geometry size, temperature and pressure affected the stresses and life of the expansion joint with finite element software.(4) Came up with some measures that can prolong the working life of the expansion joint after studying the life factors of the expansion joint.