Internal Seals for Pipes, Fittings and Expansion Joints

Internal sealing of large diameter pipelines to repair joint leaks has been utilized in municipal, industrial and power applications for over 25 years. This process consists of an ethylene propylene diene momomer (EPDM) rubber seal that is positioned over the affected area and is locked in place with two hydraulically expanded retaining bands, located at each end of the seal. Typically installations of internal seals have been limited to straight runs of pipe or in areas with minor offsets in radial configurations. However, field conditions have often identified that areas that are most vulnerable to deterioration are at tees and elbows. In general these type fittings are subject to flow induced turbulence, that result in accelerated erosion/corrosion and at a significantly greater deterioration rate than the remainder of the piping system. Recent developments in the internal sealing process have led to the creation of continuously formed seals for branch, tee and elbow configurations. In addition, specially designed seals have been installed in expansion joints in lieu of component replacement. These new type of seals are capable of providing a corrosion/erosion barrier with an operational life of 50 years and are installed in less than 24 hours with minimal impact on cost.