Plastic pipe

Abstract From the Canadian patent

A method of manufacturing a glass fibre reinforced pipe by winding a first resin impregnated pipe layer of glass fibres oriented approximately in the circumferential direction and setting the layer so formed. The set first pipe layer is then subjected to axial pressure loading by an external force and a pressure medium from inside. A second resin impregnated pipe layer having glass fibres extending approximately in the axial direction is then applied to the loaded first pipe layer and, set. After setting, the external pressure force and the pressure medium are removed so that a residual stress or prestress condition forms in the finished pipe.