Abstract: A flow rate adjusting plate for a rotary-nozzle-type molten-metal pouring unit has a shape in which one side or two sides of an octagon is or are replaced by one arc or two arcs. The arc or arcs are connected smoothly to adjacent straight sides. The plate has one hole or two holes for passing molten metal. The center of the hole corresponds to the center of the arc, and the distance between the arc and the hole is larger than the diameter of the hole.

Abstract: A door opening/closing device of door-type rotary nozzle which cannot fit collector nozzle (16) unless clampers are removed. There is no possibility of pouring molten metal while forgetting to remove the clampers (25). When the fixed frame (7) is opened or closed, a ladle is fitted by a 90 degree angle with its bottom almost vertical. So, the fitting and removing operations of the clampers (25) can be performed in front of an operator, which makes the operation very easy.

Abstract: A rotary nozzle in which at least one coil spring is removed, acting to increase the clearance between a surface of the bottom plate brick and a surface of the slide plate brick. This mechanism is capable of improving the pushing force in the vicinity of the nozzle hole, and prevents molten steel leakage, thus prolonging the life of expensive bricks.

Abstract: A rotary nozzle system attached to the outlet of a metallurgical vessel to serve as a gate valve for controlling the rate of pouring of molten metal. A slide plate brick and bottom plate brick, each having a nozzle bore, are relatively rotated in a surface-to-surface contact condition to adjust the degree of communication opening of the nozzle bores. Each of the plate bricks is formed on the outer peripheral surface thereof with a flat portion for receiving the driving force for the relative reaction force at each of four locations arranged at angular intervals of 90.degree..

Abstract: In a dual door type rotary nozzle system for metallurgical vessels, a bottom plate brick attached to the bottom shell of the vessel is adapted to be opened and closed by an inner door, and a slide plate brick slidable in surface-to-surface contact relation with the bottom plate brick is also adapted to be opened and closed by an outer door. The bottom plate brick is provided with a plurality of nozzle bores and is mounted in a case rotatably supported in the inner door by means of a bearing so that the bottom plate brick is manually rotated along with the case when the inner door is opened, thereby realizing a rotary nozzle system capable of easily and rapidly effecting the change operation of the nozzle bores of the bottom plate brick.

Abstract: A sliding rotary nozzle assembly for pouring of molten steel has a bottom plate brick and a sliding plate brick, with these plate bricks being arranged as dual doors that may be opened and closed as desired relative to a base plate that includes a flow nozzle. Each of the brick plates is provided with plural nozzle openings and is carried for rotation with the bottom plate brick being positioned on top of the sliding plate brick when the doors are closed. In case of damage to nozzle opening of the rotary bottom plate brick, the dual doors are opened and the bottom plate brick is then rotated to bring the remaining nozzle opening to the use position to make best use of the bottom plate brick and prolong the service life of the nozzle assembly.