Rørelement til en rørledning, tilsvarende rørledning og fremgangsmåde til fremstilling af et sådant rørelement

摘要

A cast-iron pipework element adapted to be buried has an external coating made up of an inner layer of zinc, a porous intermediate layer of zinc/aluminium alloy containing from 5 to 55% of aluminium, and a porous outer layer, or pore-blocking layer, comprising an organic binder, especially a water-based paint, a bitumen varnish or an epoxy resin.