Immersion nozzle

Abstract

A flow channel has lateral cross-sectional shapes that are circular in a first section, and rectangular in a second section. The flow channel in the first section is continuously connected to the flow channel in the second section. The rectangular shape has a long/short side ratio of 3 or greater and 7 or less. The second section has a cross-sectional area S2, the first section has a cross-sectional area S1, and S2>S1. There are two first openings, which are open, in one-to-one correspondence, in two side faces of the second section. There are two second openings, one of which is open while extending from one side face of the two side faces to a bottom face of the second section, and the other of which is open while extending from another one side face of the two side faces to the bottom face of the second section.

1 . An immersion nozzle having a flow channel and openings; the immersion nozzle comprising:
 a first section;   a connection section; and   a second section,   the first section, the connection section, and the second section being provided in this order from a base end side,   wherein the flow channel in the first section has a lateral cross-sectional shape that is a circular shape,   the flow channel in the second section has a lateral cross-sectional shape that is a rectangular shape,   the flow channel in the connection section has a shape with which the flow channel in the first section is continuously connected to the flow channel in the second section,   the rectangular shape of the second section has long sides each having a length a and short sides each having a length b, with a ratio a/b between the length a and the length b being 3 or greater and 7 or less,   the flow channel in the second section has a cross-sectional area S 2 , the flow channel in the first section has a cross-sectional area S 1 , and the cross-sectional area S 2  is larger than the cross-sectional area S 1 ,   the openings include two first openings and two second openings,   the first openings are open, in one-to-one correspondence, in two side faces of the second section that correspond to the two short sides,   one of the two second openings is open while extending from one of the two side faces to a bottom face of the second section, the bottom face being a face at a leading end of the second section, and   another one of the two second openings is open while extending from another one of the two side faces to the bottom face.   
     
     
         2 . The immersion nozzle according to  claim 1 ,
 wherein each of the first openings has an opening area S 3  in a corresponding one of the side faces, each of the second openings has an opening area S 4  in a corresponding one of the side faces and an opening area S 5  in the bottom face, and the opening areas S 3 , S 4 , and S 5  satisfy expressions (1) and (2) below:   
       
         
           
             
               
                 
                   
                     
                       
                         S 
                         4 
                       
                       < 
                       
                         S 
                         5 
                       
                     
                     ; 
                     and 
                   
                 
                 
                   
                     ( 
                     1 
                     ) 
                   
                 
               
             
           
         
         
           
             
               
                 
                   
                     
                       
                         ( 
                         
                           
                             S 
                             4 
                           
                           + 
                           
                             S 
                             5 
                           
                         
                         ) 
                       
                       / 
                       
                         S 
                         3 
                       
                     
                     ≥ 
                     
                       1.5 
                       . 
                     
                   
                 
                 
                   
                     ( 
                     2 
                     ) 
                   
                 
               
             
           
         
       
     
     
         3 . The immersion nozzle according to  claim 1 ,
 wherein each of the first openings has an opening area S 3  in a corresponding one of the side faces and an opening area S 6  on a flow channel side, and the opening area S 3  is smaller than the opening area S 6 .   
     
     
         4 . The immersion nozzle according to  claim 1 , wherein the immersion nozzle has a largest width of 300 mm or less.