WAERMEABSCHIRMUNG FUER BOEDEN UND GEFAESSABDECKUNGEN

A thermal shielding for covers and bottoms of gas generators and other reaction vessels intended to operate at elevated temperature and pressure is disclosed wherein the cover or bottom comprises an extension, integral with the reaction vessel, with an outer closure supporting a plurality of spaced guide tubes having fluid jackets at the inner ends thereof, the fluid jackets of a plurality of circumferentially spaced guide tubes being interconnected by concentrically spaced heat transfer tubes substantially aligned with the inner surface of the reaction vessel, the fluid jacket of one of said guide tubes being divided by baffle means into separate chambers respectively connected with supply and discharge lines for cooling fluid to be circulated through said plurality of fluid jackets and concentric connecting tubes whereby effective cooling is achieved at inner ends of said guide tubes with a minimum of congestion externally of the vessel cover or bottom. In instances where there is need for a guide tube centrally of the cover or bottom, such guide tube has a fluid jacket at the inner end thereof which closely engages fluid jackets of the circumferentially spaced guide tubes and is provided with separate supply and discharge lines for cooling fluid. The space surrounding the guide tubes between the outer closure and heat transfer tubes is preferably filled with heat insulating material.