an apparatus for manufacturing an elongate composite element in undefined lengths , the composite element containing reinforcement fibers embedded in a matrix based on a composition containing a curable resin , including a vacuum chamber , rigid - walled inlet tubing , an impregnation chamber , rigid - walled transfer tubing between the vacuum chamber and the impregnation chamber , a sizing die and , downstream of the sizing die , irradiation tubes providing radiation in the ultraviolet - visible spectrum to prepolymerize the resin .