Abstract: A plural nozzle arrangement is provided for introducing reactants, additives and so forth to steel manufacturing furnaces, in which a unitary "plug-in" type structure is provided with a plurality of self-contained blast pipes. The arrangement of the invention also provides means for introducing separately additives, reactants or shielding gases around the periphery of the blast pipes as a secondary means of introduction while still contained on the unitary structure. The unitary structure of the invention is so configured that exposure of the periphery of the individual blast pipes to the secondary additives may be varied for different applications.

Abstract: A multi-unit hoist apparatus is provided having an overload arrangement in the form of reversible pressure medium cylinders connected to the fixed end of each hoist unit in the apparatus. Appropriate controls are incorporated into the pressure medium supply to each unit, whereby if the load becomes unbalanced the unit subjected to an overload is relieved when the overload reaches a specific preset level.