| 摘要 |
In order with a cement-bound construction element, preferably for producing pipes, channels, containers and the like, having a sheet-shaped or strip-shaped protective layer extending at least over a part of the inner or outer surface, anchored in the construction element and made of a plastic or metal material resistant to mechanical and chemical effects, for example rigid PVC, V 2 A (stainless steel) or the like, to permit more economical and cheaper production than hitherto, the sheet- or strip-shaped protective layer (S) is designed in the approximate shape of a groove (R) at least in the region of one of its edges, the width of the groove being less in the region of the opening slit than in the region of the groove base. <IMAGE>
|
