DEVICE FOR INJECTING PREHEATED AIR INTO A SHAFT FURNACE AND PROCESS FOR MANUFACTURING BALL-AND-SOCKET JOINTS

摘要

The device for injecting preheated air into a shaft furnace consists of a plurality of tubular elements provided with a refractory lining, which are connected to each other by a ball-and-socket articulation (94, 96) and an expansion joint. The ball-and-socket articulations comprise a convex ball-part formed in the refractory material of the adjacent segment. They comprise a protective shell made of refractory steel which extends around the convex part up to the base of the ball-part. The radius of curvature of each ball-and-socket articulation is in the range of magnitude of half the diameter of the tubular elements.