Inner sleeve for renovating underground gas, water or sewage pipes has compression resistant layer between fibre reinforcing layers, all resinimpregnated

摘要

The sleeve (2) for lining the inside of a pipe (4) has an inner impermeable layer (6), a protective layer (8) against chemical attack, and an outer layer (16) that is opaque to UV rays. Between the protective layer and outer layer it has two reinforcing layers (10, 14) of resin-impregnated woven glass fibres and an intermediate core layer (12) with a compression resistance that gives it a deformation in the direction of its thickness of less than 10 per cent under a load of 1 kg/sq cm. The core layer can be of a closed-cell material, or of fibres, a bonding agent and micro-spheres.