Nozzle exchange device and nozzle unit

Abstract

A nozzle unit for use in a nozzle exchange device in a continuous metal casting apparatus comprises a loading opening and guiding means for sliding the nozzle unit through said opening into casting position with respect to the nozzle exchange device, wherein said nozzle unit comprises a nozzle plate made of a refractory material clad in a metal can. In order to prevent said plate from being presented to the loading opening with the wrong orientation, i.e., with the trailing edge first, said plate is provided with at least one lug at or adjacent the trailing edge, said at least one lug disposed such that the loading opening allows engagement of the base of the nozzle plate but not of the at least one lug.

1 - 14 . (canceled) 
     
     
         15 . A nozzle unit for use in a nozzle exchange device in a continuous metal casting apparatus, said nozzle exchange device comprising a loading opening and a guide for sliding the nozzle unit through said opening into casting position with respect to the nozzle exchange device, wherein said nozzle unit comprises
 A) a nozzle plate made of a refractory material partly clad in a metal can, said plate having a shape inscribed in a prism, and being defined by
 a) a first leading edge and a second, opposite trailing edge defining the first and second bases of the prism, transverse to a first axis (X1), 
 b) an upper slide surface defined by a first and a second axis (X1, X2) and a lower support surface forming a first pair of opposite and parallel joining faces of the prism, 
 c) a first and second side edges substantially parallel to said first major axis (X1) linking the first and second bases of the prisms as well as the first pair of opposite joining faces; 
 d) a through bore fluidly connecting the upper slide surface and the lower support surface, said through bore being offset along said first axis (X1), and 
   B) a tubular duct comprising a central bore in fluid communication with the through bore of the plate, one end of said duct being fixed to the lower support surface of the plate, said central bore opening to ambient through at least one opening located at or near the opposite end of the tubular duct;   wherein, at least one lug is provided at or adjacent the trailing edge, said at least one lug being transverse to said first major axis (X1) and extending substantially beyond the perimeter defining the base of the prism, and in that the flexural yield point of said at least one lug is at least 10 kgf and at most 2000 kgf.   
     
     
         16 . Nozzle unit according to  claim 15 , wherein the flexural yield point of said at least one lug is at least 20 kgf and at most 1000 kgf. 
     
     
         17 . Nozzle unit according to  claim 15 , wherein the geometry of the bases of the prism is selected from the group consisting of: (a) a rectangle, (b) a parallelogram, (c) a trapezoid, (d) a rectangle wherein at least the two angles adjacent the lower support surface are cut off to mate the geometry of the guide of a nozzle exchange device. 
     
     
         18 . Nozzle unit according to  claim 15 , wherein the at least one lug is adjacent to at least one side edge. 
     
     
         19 . Nozzle unit according to  claim 15 , wherein the at least one lug is made of a ductile metal and is fixed to or is integral part of the metal can cladding the refractory, and has a geometry selected from the group consisting of:
 (a) L-shaped plate, with the vertical bar of the “L” fixed to the plate at or adjacent the trailing edge and the horizontal bar of the “L” extending outwards beyond the surface of the side edge it is adjacent to;   (b) L-shaped plate, with one bar of the “L” running parallel to a side edge and the other bar of the “L” extending outwards beyond the surface of the side edge it is adjacent to, and at or adjacent the trailing edge.   (c) a plate, extending outwards beyond the surface of the side edge it is adjacent to, and substantially flush with the trailing edge;   (d) in the case of a nozzle plate wherein the side edges are not flat, two lugs adjacent the trailing edge, each extending beyond the base defining the prism such as to be enclosed within the smallest rectangle circumscribing said base;   (e) in the case of a nozzle plate wherein the prism basis consists of a rectangle with at least two cut off angles, two lugs adjacent the trailing edge, each having the geometry of the cut off parts and being complementary to form therewith a rectangle;   (f) in the case of a nozzle plate wherein the prism basis consists of a rectangle with at least one protrusion jutting out of at least one edge adjacent one side edge, the at least one lug being substantially flush with the protrusion and with the lower edge adjacent the lower support surface;   (g) a curved bar or blade fixed to the support surface; and   (h) curved half shells fixed to a side edge.   
     
     
         20 . A kit of parts comprising a nozzle unit as defined in  claim 15 , and a nozzle exchange device for changing a nozzle unit during continuous casting of metal, wherein the nozzle exchange device comprises:
 (a) a first fixed plate comprising a through bore suitable for being brought in fluid communication with a source of metal melt, said first fixed plate comprising a first lower slide surface;   (b) a loading opening for loading the second, moveable nozzle plate, said loading opening allowing engagement of the base of the nozzle plate but not of the at least one lug,   (c) a guide for sliding the moveable plate in a direction parallel to the first axis (X1) through said opening into casting position defined as the position wherein the through bores of the first, fixed plate and the second, moveable plate are in fluid communication,   (d) a discharge opening at the opposite end of the guide for discharging the nozzle unit after use upon pushing it with a new nozzle unit, and   (e) a thruster suitable for pushing a moveable nozzle unit from its loading position into its casting position and having a pushing force superior to the flexural yield force or ultimate flexural force of the at least one lug, and wherein,   the upper slide surface of the exchangeable nozzle unit is suitable for sliding along the first slide surface of the first fixed plate and for bringing in fluid communication the through bores of the first and second plates.   
     
     
         21 . A kit of parts according to  claim 20 , wherein the thruster is suitable (a) for pushing a first nozzle unit from the loading position to the casting position, (b) for pushing a first nozzle unit from the casting position to an obturating position wherein the through bore of the first fixed plate faces a blank surface of the upper sliding surface of the nozzle plate, and (c) for pushing a second nozzle unit from the loading position to the casting position, thus pushing the first moveable plate out through the discharge opening. 
     
     
         22 . A kit of parts according to  claim 20 , wherein the nozzle unit cannot be loaded for engagement into the loading opening if presented in any other position than with the leading edge first. 
     
     
         23 . Continuous metal casting line comprising a kit of parts according to  claim 20 . 
     
     
         24 . Continuous metal casting line according to  claim 23 , wherein the nozzle exchange device is located at an outlet of a tundish, 
     
     
         25 . Metal can for cladding the plate of a nozzle unit according to  claim 15 , having a shape suitable for cladding at least a portion of all the faces of the nozzle plate but the upper sliding surface characterized in that it comprises at least one lug provided at or adjacent the trailing edge, said at least one lug being transverse to a first major axis (X1) and extending substantially beyond the perimeter defining the basis of the prism, and in that the flexural yield point or ultimate flexural force of said at least one lug is at least 10 and at most 2000 kgf. 
     
     
         26 . Metal can according to  claim 25 , wherein the at least one lug has a flexural yield point or ultimate flexural force of at least 20 kgf and at most 1000 kgf. 
     
     
         27 . Metal can according to  claim 25 , wherein the at least one lug is an integral part of the can. 
     
     
         28 . Metal can according to  claim 25 , wherein the at least one lug is fixed to the can with an attachment selected from the group consisting of a soldering line, a welding line, cement, glue, rivets and screws.