The Stamina of Non-Gasketed, Flanged Pipe Connections

摘要

Most international design codes for pressure equipment, such as BS 5500, ASME VIII and the new European standard prEN 13455, provide rules and equations to allow gasketed joints to be safely designed for a given internal pressure design and loading. In general they do not take into account the effect of axial plus lateral loads and bending moments acting in conjunction with the main pressure load. This paper is based on two years of experimental and finite element studies of both standard/conventional ANSI (gasketed) and modern VCF (non-gasketed) flanged joints (according to the VERAX Compact Flange System). This has led to a deeper understanding of the requirements for a successful assembly and long term usage. ANSI and VCF joints have been subject to internal pressure, axial and lateral forces, with these loads having been applied both singly and in combinations. Mode of load acting in the joint i.e. static or dynamic has been studied for both kinds of joints. Experimental and analytical results are compared. Some practical considerations on the use of important emerging technology i.e. non-gasketed pipe joints in comparison to conventional gasketed systems are presented. Of fundamental importance is an insight into the mechanism of the bolted joint showing the effect from an external load on a preloaded bolt. It is found that it can be made near zero hence, in a properly built, non-gasketed bolted joint a static mode rules, and therefore the stamina of such a joint is unlimited. This paper demonstrates that the novel system is an efficient and well-engineered alternative to traditional joints.