Stopper

Abstract

The invention generally relates to a stopper for controlling the flow of molten metal from a metallurgical vessel like a tundish. Any references made hereinafter, relating to the design, construction and/or function of the stopper, refer to the typical use position of such stopper, i.e. a vertical oriented position.

1 . Stopper rod for flow control of molten metal from a metallurgical vessel, comprising
 a) an elongated body ( 10 ) with a longitudinal axis A and made of a refractory ceramic material,   b) a bore hole ( 14 ), extending from an upper surface of said body towards its opposite lower end ( 101 ) and ending at a distance to an outer surface ( 10   s ) of the lower end ( 101 ) of said body ( 10 ),   c) at least one gas channel ( 22 ), having a cross-sectional area which is smaller than that of the average cross-sectional area of the bore hole ( 14 ) and extending from a lower end ( 14   b ) of the bore hole ( 14 ) to at least one outer surface section at the lower end ( 101 ) of the body ( 10 ), whereby   d) the length of said gas channel ( 22 ) is larger than the distance defined by a straight line between its ends ( 22   i ,  22   o ).   
   
   
       2 . Stopper rod according to  claim 1 , wherein the length of the gas channel ( 22 ) is between 5 and 30 times greater than the distance defined by a straight line between its ends ( 22   i ,  22   o ). 
   
   
       3 . Stopper rod according to  claim 1 , wherein the gas channel ( 22 ) is arranged in a helical manner. 
   
   
       4 . Stopper rod according to  claim 1 , wherein the gas channel is arranged in a meander like manner. 
   
   
       5 . Stopper rod according to  claim 1 , wherein the gas channel ( 22 ) enters the bore hole at a distance from the lower most end ( 14   b ) of bore hole ( 14 ). 
   
   
       6 . Stopper rod according to  claim 5 , wherein the said distance is between 20 and 200 mm. 
   
   
       7 . Stopper rod according to  claim 1 , wherein the gas channel provides an average cross-sectional area of between 0.5 and 4 mm 2 . 
   
   
       8 . Stopper rod according to  claim 1 , wherein the cross-sectional area of the gas channel ( 22 ) varies along its length. 
   
   
       9 . Stopper rod according to  claim 1 , wherein the gas channel ( 22 ) has a total length between 50 and 1.000 mm. 
   
   
       10 . Stopper rod according to  claim 1 , wherein the gas channel ( 22 ) extends along the longitudinal axis A of the body from the lowermost surface section ( 12 ) of the body ( 10 ) into said body ( 10 ). 
   
   
       11 . Stopper rod according to  claim 1 , wherein the at least one gas channel ( 22 ) is arranged at least partly within or around a refractory shaped part ( 30 ) positioned within and/or affixed to said body ( 10 ).