Abstract: A refractory plate assembly for use in a sliding closure unit includes a plate-shaped refractory member having therethrough at least one discharge opening and a metal jacket surrounding the peripheral edge of the refractory member. Such assembly is constructed by providing the refractory member with at least one indentation extending inwardly from the peripheral edge of the refractory member. A metal ring is positioned to surround the peripheral edge of the refractory member such that a portion of the metal ring extends across the indentation. This portion of the metal ring is pressed into the indentation until an innermost external surface of such portion is spaced a predetermined distance from the external surface of the metal ring at a position at the peripheral edge of the refractory member opposite the indentation.

Abstract: A sliding closure unit includes at least one stationary plate having therethrough a discharge opening, and a movable plate mounted in sliding contact with the stationary plate, the movable plate having therethrough first and second discharge openings and including a closing area. Guides define alternative first and second paths of movement of the movable plate in directions along respective first and second tracks extending between the closing area and the first and second discharge openings of the movable plate. A single drive is connected to the movable plate for moving the movable plate along a selected such path between a closed position whereat the closing area is aligned with the discharge opening of the stationary plate and a selected open position wherein one of the discharge openings of the movable plate is aligned with the discharge opening of the stationary plate.