APPARATUS FOR BLOWING PREHEATED AIR INTO A SHAFT FURNACE AND METHOD OF MAKING CONVEX COMPONENTS OF BALL JOINTS OF PIPES USED FOR BLOWING IN SUCH PREHEATED AIR

摘要

Equipment for injecting preheated air into a pit furnace consists of several tubular parts lined with refractory material which are joined together by means of a ball-and- socket-joint union 94, 96 and an expansion joint. The ball-joint union comprises a convex ball section created in the refractory material in adjacent segments. They comprise a protective casing made of refractory steel passing around the convex section to the base of the ball joint. The size of the radius of curvature in each ball- joint union is of the order of half the diameter of the tubular parts.