Abstract: A fixed plate (15) is provided in a fixed metal frame (14). An opening and closing metal frame (17) having a movable plate (21) is attached to the fixed metal frame (14) so as to be openable and closable. The fixed metal frame (14) is provided with a pressurizing mechanism (23) applying a pressure in a closing direction generated by a spring (25) to the opening and closing metal frame (17) in a closed state. An actuating member (29) is movably provided at a position facing the pressurizing mechanism (23). Cam surfaces (30d, 32a) are provided between the actuating member (29) and the pressurizing mechanism (23). The spring (25) is deformed against an urging force thereof on the basis of operations of the cam surfaces (30d, 32a) in accordance with a movement of the actuating member (29), and the pressure applied to the opening and closing metal frame (17) is strengthened.

Abstract: In a rotary nozzle brick body formed into a substantially egg-like shape in it's plan view, the present invention secures a contact area of a nozzle portion and improves a configuration factor which considerably affecting the durability of the body. A rotary nozzle brick body is characterized in that the external shape in plan view is comprised of first circular portions (G), second circular portions (H), third circular portions (K), and tangent lines connecting the first circular portions and third circular portions so that a substantially elliptical shape is formed by increasing the circular portion and shortening the tangent lines, instead of a substantially egg-like shape having long tangent lines.

Abstract: A filler for a ladle tap hole valve, characterized by comprising a sand and a feldspar to be externally added and mixed together so that the total quantity of alkalis in the filler is 0.3 to 1.5 mass %, the feldspar having a particle size distribution of 0.3 to 1.7 mm, the sand being composed of 40 to 100 mass % of silica sand having a particle size distribution of 0.3 to 1.7 mm and 60 to 0 mass % of chromite sand having a particle size distribution of 0.1 to 0.85 mm.

Abstract: In a rotary nozzle brick body formed into a substantially egg-like shape in its plan view, the present invention secures a contact area of a nozzle portion and improves a configuration factor which considerably affecting the durability of the body. A rotary nozzle brick body is characterized in that the external shape in plan view is comprised of first circular portions (G), second circular portions (H), third circular portions (K) and tangent lines connecting the first circular portions and the third circular portions so that a substantially elliptical shape is formed by increasing the circular portions and shortening the tangent lines, instead of a substantially egg-like shape having long tangent lines.

Abstract: A filler sand for a ladle tap hole valve contains 45 to 55 mass % of zircon sand, 30 to 40 mass % of chromite sand and 10 to 20 mass % of silica sand and is blended externally with 0.05 to 5 mass % of carbon black calculated based on the total amount of the sands; or contains 30 to 90 mass % of chromite sand and 10 to 70 mass % of silica sand and is optionally blended externally with 0.05 to 5 mass % of carbon black, wherein 95 mass % or more of the chromite sand consists of particles having diameters falling within a range of 150 to 850 &mgr;m, 60 mass % or more of the chromite sand consists of particles having diameters falling within a range of 212 to 600 &mgr;m, 95 mass % or more of the silica sand consists of particles having diameters falling within a range of 300 to 1180 &mgr;m, and 90 mass % or more of the silica sand consists of particles having diameters falling within a range of 600 to 1180 &mgr;m.

Abstract: A filler sand for a ladle tap hole valve contains 70 to 90 wt % of chromite sand and 10 to 30 wt % of silica sand and is blended externally with 0.05 to 5 wt % of carbon black calculated based on the total amount of the chromite sand and the silica sand; or contains 70 to 90 wt % of chromite sand and 10 to 30 wt % of silica sand, wherein the chromite sand has a particle diameter distribution such that 99% or more of the chromite sand consists of particles having diameters ranging from 150 to 850 &mgr;m and that 95% or more of the chromite sand consists of particles having diameters ranging from 200 to 600 &mgr;m, and the silica sand has a particle diameter distribution such that 95% or more of the silica sand consists of particles having diameters ranging from 150 to 850 &mgr;m and that 80% or more of the silica sand consists of particles having diameters ranging from 200 to 600 &mgr;m.

Abstract: A filler for a sliding gate containing 70 to 90 wt % of chromite sand and 10 to 30 wt % of silica sand in which the particle size distribution of the chromite sand is substantially from 500 to 1,000 .mu.m, which is not melted, sintered or penetrated by molten metal (molten steel) poured in a ladle in a steel works, and therefore is easily discharged to let the gate through.

Abstract: A molten metal pouring nozzle for a continuous casting machine having an endless-travelling type mold, wherein the endless-travelling type mold is formed with two pairs of opposing wall members endlessly travelling in the same direction and at the same speed, and one end of the pouring nozzle is connected to a tundish for receiving molten metal, and the other end of the pouring nozzle is inserted into the mold. The molten metal pouring nozzle of the present invention comprises a nozzle body made of a refractory and a flow regulator made of a refractory. The nozzle body (14, 20) has a bore (1a, 3a), through which molten metal flows, along the axial line thereof, and the sectional area of the downstream end portion of the bore (1a, 3a) becomes gradually larger toward the downstream end thereof. The flow regulator (15, 18) is arranged at the center of the downstream end portion of the bore (1a, 3a) of the nozzle body (14, 20).