Patent ID: 6413602
Filing Date: 2002-07-02
Classification: F16L,Y10S,Y10T

Abstract:
A process for conveying drinking water which comprises passing drinkable water through a pipe comprising a plurality of layers, wherein the inner most layer comprising a polyolefin is covered with an outer layer comprising a thermoplastic polymer which is impervious to hydrocarbons, wherein the polyolefin is selected from the group consisting of polyethylene, polypropylene, copolymers of ethylene and of an alpha-olefin, copolymers of ethylene and of esters of unsaturated carboxylic acids, copolymers of ethylene and of vinyl derivatives of saturated carboxylic acids, and mixtures thereof; and the outer layer is 15 to 100 times less permeable to hydrocarbons than polyethylene, wherein the thermoplastic polymer impervious to hydrocarbons is selected from the group consisting of polyvinylidene fluoride, copolymers of ethylene and of vinyl alcohol, polyesters, and mixtures of polyamides with polyolefins.