Swivel joints operating at 5,800 psi are exposed to pulsating pressure, vibration, axial movement, and abrasive fluid. Seal failure is often related to insufficient contact stress, poor surface finish, seal extrusion, or uneven wear on the ball race and sealing surface.
Improved sealing technology starts with a stable structural design. The seal should be supported against extrusion, the groove should control seal deformation, and the mating surface should be machined with consistent roundness and finish.
Material selection is equally important. Elastomer compounds must match the working temperature, pressure, and medium. For sour service, seal materials and metallic parts should be selected in accordance with NACE MR0175 principles.
Assembly quality has a direct effect on sealing life. The seal groove, bearing race, and thread surfaces should be cleaned before assembly, lubricated with compatible grease, and tightened according to the specified procedure.
Regular inspection should focus on leakage, abnormal rotation torque, corrosion, impact damage, and seal extrusion. A planned repair-kit replacement cycle is preferable to running the joint until leakage occurs.
