Development of pressure balanced expansion joints

摘要

Bellows can reduce the reaction force at thesupports, arising from the elongation of the piping systems.Bellows are used for the absorption of thermal expansion of pipingin liquid and gas transportation systems. But, under high internalpressure, bellows elongate and make a large reaction force at the sipports.We quantatively examined these reaction forces at the supportscaused by thermal expansion and internal pressure. Its results madeclear that the reaction force dur to internal pressure was muchlarger than the one due to thermal expansion. Therefore, wedeveloped a few kinds of pressure balanced expansion joints. Thepresent paper reports on the structure and mechanism of these devices.