Discharge Nozzle For Molten Metal In Molten Metal Vessel, Method For Operation Of Converter Having The Discharge Nozzle, And Sleeve Replacing Apparatus For Discharge Nozzle Of Molten Metal Vessel

Abstract

An arrangement for reducing an average discharging time in a molten metal vessel, such as a converter, having a molten-metal discharge nozzle particularly a molten-metal discharge nozzle comprises a sleeve-shaped refractory member so as to achieve enhanced operational efficiency of the molten metal vessel. A discharge nozzle comprises an upper sleeve mounted in a refractory lining of a converter and a lower sleeve adapted to be detachably attached to a lower end of the upper sleeve, wherein a hole sectional area of the lower sleeve is set in the range of 60 to 98% of a hole sectional area of the lower sleeve in its used state requiring replacement.

1 . A discharge nozzle for molten metal in a molten metal vessel, comprising an upper sleeve and a lower sleeve adapted to be detachably attached to a lower end of said upper sleeve, wherein said lower sleeve is formed with an inner hole in such a manner that a cross-sectional area of the inner hole of said lower sleeve in its newly-installed state is in the range of 60 to 98% of a cross-sectional area of the inner hole of said lower sleeve in its used state requiring replacement.  
   
   
       2 . The discharge nozzle as defined in  claim 1 , wherein said upper sleeve is formed with an inner hole in such a manner that a cross-sectional area of the inner hole of said upper sleeve in its newly-installed state is in the range of 85 to 200% of the cross-sectional area of the inner hole of said lower sleeve in said used state requiring replacement.  
   
   
       3 . The discharge nozzle as defined in  claim 1 , wherein said upper sleeve is adapted to be installed in said molten metal vessel in such a manner that the lower end of said upper sleeve protrudes from an outer surface of said molten metal vessel.  
   
   
       4 . A discharge nozzle for molten metal in a molten metal vessel, comprising: 
 an upper sleeve; and    a lower sleeve adapted to be detachably attached to a lower end of said upper sleeve, in such a manner that said lower sleeve is associated with an elastic member for allowing said lower sleeve to be brought into press contact with said upper sleeve, and held by a metal housing incorporating said elastic member to form an integral unit, wherein said lower sleeve is brought into press contact with said upper sleeve by a reaction force of said elastic member compressed when said metal housing is supported by a rail of a retention member fixed to said molten metal vessel, and allowed to be detached from said upper sleeve when moved along a longitudinal direction of said rail.    
   
   
       5 . The discharge nozzle as defined in  claim 4 , wherein said metal housing has an ambient-air inlet for introducing ambient air to said elastic member.  
   
   
       6 . The discharge nozzle as defined in  claim 4 , wherein said rail has opposite longitudinal ends each formed with an inclined surface adapted to relax the compression of said elastic member.  
   
   
       7 . The discharge nozzle as defined in  claim 4 , wherein each of said upper sleeve and said lower sleeve is formed to have a generally circular-shaped contact surface therebetween, and an inner hole having an axis aligned with a center of said contact surface, said contact surface having an outer periphery which includes a pair of parallel edges each extending in a direction orthogonal to said moving direction of said lower sleeve during the detachment and having a length greater than an inner diameter of said nozzle hole.  
   
   
       8 . The discharge nozzle as defined in  claim 4 , wherein a cross-sectional area of the inner hole of said lower sleeve in its newly-installed state is in the range of 60 to 98% of a cross-sectional area of the inner hole of said lower sleeve in its used state requiring replacement.  
   
   
       9 . The discharge nozzle as defined in  claim 8 , wherein a cross-sectional area of the inner hole of said upper sleeve in its newly-installed state is in the range of 85 to 200% of the cross-sectional area of the inner hole of said lower sleeve in said used state requiring replacement.  
   
   
       10 . The discharge nozzle as defined in  claim 8 , wherein said upper sleeve is adapted to be installed in said molten metal vessel in such a manner that the lower end of said upper sleeve protrudes from an outer surface of said molten metal vessel.  
   
   
       11 . A sleeve replacing apparatus for the discharge nozzle as defined in  claim 4 , comprising: 
 a new-sleeve holding portion adapted to hold a new lower sleeve which is the lower sleeve in its unused state and before a replacement operation;    a current-sleeve receiving portion adapted to receive therein the lower sleeve which is currently in press contact with said upper sleeve while being supported by said rail;    an old-sleeve holding portion adapted to hold an old lower sleeve which is the lower sleeve in its used state and after said replacement operation, and arranged together with said new-sleeve holding portion and said current-sleeve receiving portion in a linear manner; and    an actuator adapted to push out said new lower sleeve held by said new-sleeve holding portion toward said current-sleeve receiving portion, said actuator being operable to push out said new lower sleeve toward said current-sleeve receiving portion in such a manner that said new lower sleeve is brought into press contact with said upper sleeve while being supported by said rail, so as to allow said lower sleeve which has been in press contact with said upper sleeve to be pushed out and moved to said old-sleeve holding portion and held by said old-sleeve holding portion as an old lower sleeve.    
   
   
       12 . The sleeve replacing apparatus as defined in  claim 11 , which is adapted to be moved while being held by a manipulator, and provided with a guide rod adapted to be inserted into a guide horn provided on the molten metal vessel, wherein, during said replacement operation, said guide rod is inserted into the guide horn according to a manipulation of said manipulator, so as to fix a position of the sleeve replacing apparatus.  
   
   
       13 . A method for operation of a converter having a molten-metal discharge nozzle which includes an upper sleeve and a lower sleeve detachably attached to a lower end of said upper sleeve, comprising: 
 allowing said lower sleeve to have an inner hole formed such that a cross-sectional area of the inner hole of said lower sleeve in its newly-installed state is in the range of 60 to 98% of a cross-sectional area of the inner hole of said lower sleeve in its used state requiring replacement; and    operating said converter under the condition that the cross-sectional area of the inner hole of said lower sleeve is maintained at a value equal to or less than a cross-sectional area of an inner hole formed in said lower sleeve.    
   
   
       14 . The method as defined in  claim 13 , which includes operating said converter under the condition that a cross-sectional area of the inner hole of said upper sleeve at a time when said lower sleeve is replaced and newly installed is maintained in the range of 85 to 200% of the cross-sectional area of the inner hole of said lower sleeve in said used state requiring replacement.