| 摘要 |
A tube 1 is provided with a protective sheath by applying cement mortar 3 or a mixture of cement mortar and fibres to the outer wall of the tube, while the tube is slowly rotating, and wrapping the mortar with a banding element 4 wound about it. The use of impervious sheet material for the banding element has the advantage that it forms a closed outer skin and hinders the evaporation of mixing water in the mortar, rendering subsequent treatment unnecessary, also that it protects the mortar from media which have a corrosive action on cement. The use of a fleece, an unwoven fabric or a woven fabric has the advantage that the banding element presses into the cement slurry and forms a common layer therewith; sealing and protection against corrosive action can then be achieved by applying a bitumen or plastics material coating. <IMAGE> |
