US Patent 9334998 Tubular liner for rehabilitating defective sewers

A tubular liner for rehabilitating sewers includes a circumferentially expandable reinforcing layer impregnated with a light-curable reactive resin, and an outer tubular film surrounding the reinforcing layer and formed of a radially expandable material impermeable to UV light, in particular a liquid-tight and gas-tight plastic film. The tubular liner can be pulled into a sewer to be rehabilitated and can be expanded, in particular by using compressed air, so that the reinforcing layer and the outer tubular film contact the inner wall of the sewer before the reactive resin is cured. A protective tube made of a tear-resistant material is disposed around the outer tubular film and has a connecting portion extending in the longitudinal direction of the outer tubular film and being expandable in the circumferential direction by introducing compressed air into the tubular liner.