Patent ID: 7588718

Claim:
An Apparatus for injecting gas into a vessel, including a gas flow duct extending from a rear end to a forward end from which to discharge gas from the duct; cooling water supply and return passages extending through a wall of the gas flow duct from its rear end to its forward end for supply and return of cooling water to the forward end of the duct, the cooling water supply and return passages being defined by three concentric tubes that form the wall of the duct; and an annular duct tip disposed at the forward end of the duct and having an internal cooling water passage connecting with the cooling water supply and return passages so as to receive and return a flow of cooling water to internally cool the duct tip; wherein the duct tip is of hollow annular formation and comprises a hollow shell and a partitioning structure disposed within the shell, the partitioning structure having a ring and a plurality of circumferential flanges that project outwardly from the ring to the shell so as to form said water cooling passage as a series of annular water flow galleries each extending circumferentially around the tip and interconnected for flow of cooling water sequentially through the galleries from the cooling water supply passage to the cooling water return passage, and said circumferential flanges also serving as buttress supports for the shell.