Corrosion protective band for underground pipe joints with metal parts

Abstract

A system of protecting pipes with bell and spigot joints (having metal parts) from corrosion .[.be.]. .Iadd.by .Iaddend.fitting between the spigot and bell at least one dry band of open celled material (preferably reticulated polyurethane foam) having a hydratable cement (preferably Portland cement) impregnated therein and engaging the band between the bell and the spigot. On wetting of the band, the cement is hydrated to form a water impervious hard sealant in the joint which releases alkalinity to protect the metal.

We claim: .[.1. A distortable band, suitable for being fit into a joint between first and second continuous successive lengths of pipe made of ceramic earthen material wherein a bell formed on one end of the first length is engaged by a spigot formed on an end of a second length, the band made of a cellular water invadable material impregnated with a dry hydratable cement which is reactive with water to hydrate thereby depositing a water impervious hard substance in the joint..]. .[.2. The band of claim 1 comprising a reticulated polyurethane foam..]. .[.3. The band of claim 1 with the cement being Portland cement..]. .[.4. The band 
     
        of claim 1 and a water-permeable sheath around the band..].  5. The band 
     
     
        of claim 7 with the cement being Portland cement. 6. The band of claim 7 with the sheath being a nonwoven polyester fabric.  .Iadd.7. A distortable band, suitable for being fit into a joint between first and second continuous successive lengths of pipe made of concrete, wherein a bell formed on one end of the first length is engaged by a spigot formed on the end of a second length, the band made of a cellular water invadable material impregnated with a dry hydratable cement which is reactive with water to hydrate thereby depositing a water impervious hard substance in the joint, a water permeable sheath around the band..Iaddend.