Patent ID: 8596959

Claim:
A gas turbine engine comprising an array of hollow airfoils within an annular duct supported in an engine case assembly and a heat insulation system for an oil tube extending through one of the hollow airfoils, the heat insulation system including an insulation tube surrounding the oil tube and extending substantially along a length of the oil tube, the insulation tube having one of a weld and a braze joint at each of its opposed ends which integrally and sealingly connect the insulation tube to the oil tube, thereby defining a dead air annulus between the oil tube and the insulation tube: wherein the opposed ends of the insulation tube surrounds a tubular body of the oil tube and are affixed to respective annular shoulders disposed at respective opposed first and second end portions of the oil tube and projecting outwardly with respect to the tubular body; and wherein the insulation tube comprises a metal sleeve around and affixed to an outer surface of the insulation tube near the first end portion of the oil tube.