PIPELINE FIELD JOINT COATING FOR WET INSULATION FIELD JOINTS

摘要

Thermoplastic wet insulation field joints for pipelines in bodies of water utilize the fast gelling nature of thermosetting systems, or other suitable fillers, coupled with a fully fused thermoplastic outer sheath for protecting the pipe joint from water contact. The outer sheath is fully fused circumferentially to the parent coating at each end of the field joint, and an outer closure patch is then fused to the sheath over the joining area and/or injection ports. This totally seals the filler material from direct contact with water, preventing water ingress from reaching the pipe surface. Hydrolysis of the infill material is thus also prevented. By use of a fast setting or solid infill material the system gains sufficient strength almost immediately to withstand the rigors of handling during the lay operation.