Ceramic-insulated pipe for the transport of hot fluids

Claim 1

A duct for the transport of high-temperature fluids, comprising: a continuous metal outer pipe; a tubular ceramic body received in said outer pipe but circumferentially spaced therefrom and defining a passage within said body for said fluid; a plurality of annular metallic stressing elements extending circumferentially around and exerting inward prestress upon said ceramic body resisting the application of outward pressure by said fluid to said body, said elements being disposed inwardly of said pipe, said body and said elements together constituting a tubular member received within said pipe with all around clearance; an intermediate cylindrical metal sleeve disposed between said pipe and said member over at least the full length of said member and axially extending over a plurality of said elements and surrounding said body; first circumferential welds formed between opposite ends of said sleeve and said pipe, thereby securing said sleeve to said pipe and preventing parasitic fluid flow between said pipe and said sleeve; and respective second circumferential welds between said elements and said sleeve, thereby mounting said member within said sleeve and thus mounting said member via said intermediate sleeve within said pipe while preventing parasitic fluid flow between said member and said sleeve.