Corrosion protective collar for underground pipe joints with metal parts

摘要

A method of protecting pipes with bell and spigot joints (having metal parts) from corrosion by fitting between the spigot and bell at least one dry band of open celled material (preferably reticulated polyurethane foam) having a particulate alkaline material (preferably Portland cement) impregnated therein and engaging the band between the bell and the spigot. On wetting of the band, the alkaline material is hydrated to protect the metal.