Patent Publication Number: US-6213357-B1

Title: Nozzle exchanger

Description:
The invention relates to continuous hot casting installations which serve in particular for making raw steel products. 
     An essential element of such an installation is the casting member which is known as an immersed nozzle. Mounted on a metallurgical or casting container, it ensures good distribution of the flow of liquid metal, which must ultimately abut against a continuous casting channel, where a cooling and progressive solidification of the liquid metal take place. All the components in contact with the metal at a high temperature are naturally made of refractory material. They are likewise subject to wear or blockage, in particular the nozzle, which has to be changed periodically in order to prolong the casting cycle. 
     Furthermore the close presence of the hot metal creates a very difficult environment for all the systems which are provided. All handling is delicate in this region. The zones in question are also congested and often tight. The metallurgical containers and the distributors of the continuous casting in particular are often provided with feet or reinforcements on their bases. 
     In European patent EP-B-0 441 927, the applicants have proposed a device for plugging and controlling continuous hot casting designed to be mounted on a metallurgical or casting container of the type comprising, on a framework, a plugging assembly, a channel providing a casting tube known as an immersed nozzle, adjacent to the outlet of the plug, spring thrusters to maintain this nozzle in an operative position in line with the plug assembly, on the feed channel, which is designed to receive another nozzle in a position of readiness, and an offset ram traverser provided with an arm for engaging the nozzles, all supported on a cam track. 
     It would seem difficult to improve on it, in particular to make it more compact. However the present invention aims to improve these items still further. 
     According to one important aspect of the invention the body of the ram is provided with a sensor designed to co-operate with the cam track and it also supports the driving arm, whereas the rod of the ram is fixed to the structure. This allows a reduction in the dimensional bulk of the device. 
     Preferably the ram is retracted while a nozzle is in operation, whereas it is extended for displacing the nozzles by pushing on them. 
    
    
     Other features and advantages of the invention will become apparent from a study of the detailed description which follows, together with the accompanying drawings, in which: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a simplified plan view of a nozzle device according to the invention, 
     FIG. 2 is a vertical section on the line II—II in FIG. 1, and 
     FIG. 3 is a vertical section on the line III—III in FIG.  1 . 
    
    
     The accompanying drawings disclose elements of a certain character. They can thus serve not only to provide a better understanding of the description, but also to contribute to defining the invention. 
     The framework of the device is defined by longitudinal beams  102  and  103 , joined together on the right by a transverse beam  101  (FIG. 1) and lying over lower parallel beams  104  and  105  (FIG.  3 ). On the left (in FIG. 3) the location of the beams is ensured by an assembly comprising guide elements of a ram body  504  and a frame  106 . 
     Above the structure there is provided a cover  200  enclosing a refractory member  201  (FIGS.  2  and  3 ). This member  201  ensures a connection with the refractory of the container under which the device is mounted, in a known manner. Underneath there are provided two other superposed refractory plates  202  and  203 . Forming an assembly of three refractory plates with the central plate  202 , the plates  201  and  203  are fixed whereas the plate  202  can slide between the plates  201  and  203 . The central plate  202  moves on the command for the nozzle to deliver with the aid of a ram control mechanism, not illustrated here (see EP-B-0 441 927). The plate  202  is located within a moving frame capable of sliding between the elements  104  and  105  of the framework (FIG.  3 ). The covers  301  and  302 , provided with resilient sealing means, serve to ensure the sealing between the refractory plates  201  to  203 . 
     The feed track of the nozzles is visible in end view at  310  in FIG.  2 . In FIG. 3 can be seen one of the guiding profiles designed to co-operate with one of the straight edges of the nozzle flange: at  320  and  321  slightly rising profiles, then the thrusters  323  to  325  (elastic returns for example at  330  and  340  in FIG.  2 ), and finally an exit profile  326  which falls once again. 
     Mounted at the edge of the device are bevels such as  400  (FIG. 3) which support and guide the mechanism for displacing the nozzles. 
     The latter comprises a ram body  501  (FIG. 2) mounted to slide on bronze pads  502  and  503  in a U-shaped location identified as  504 . The head of this ram body has a claw  510  (FIG. 3) provided with a lateral spur-sensor  511  which follows a horizontal cam track  520 . In addition there is pivotally connected to the claw  510 , preferably co-axially with the spur  511 , a block  530  articulated around the spur sensor  511  which can furthermore co-operate with a complementary oblique portion of the cam track. And, at the free end of this articulated rod there is mounted a driving arm  540 , seen in section in FIG. 3 but visible in FIG. 2 in the nozzle supply path (not shown). 
     The end of the rod of the ram is visible at  550  in FIG. 3, where it is surmounted by the hydraulic feed system  560 . This system communicates with the rod to provide hydraulic supply to the ram. The rod is mounted fixed or pivoted on the structure with freedom for at least partial angular deflection (about a horizontal axis). 
     When a nozzle (not shown) is in operation the ram is retracted and is present in the position A (FIGS.  1  and  3 ). The driving arm is situated above the cam track  521 , and permits introduction of a fresh nozzle without necessarily raising the distributor. On the side where the head of the ram is present, the fresh nozzle waits on the feed track in contact with the operative nozzle. After this, at the moment when one wishes to exchange the nozzles, the ram is caused to extend, it pushes the two nozzles together in such a way that the new one comes into the operative position whereas the previous one leaves to the left (FIG. 3) and can then be withdrawn from the steel bath in a known manner. After this the ram can return to its retracted position. 
     The arrangement described above is particularly compact. In particular the operation of the ram contributes to its compactness since an important part of the path of the body of the ram takes place within the dimensions of the remainder of the device. Moreover it allows very rapid changing of the nozzle, which is essential. Furthermore this changing takes place when the ram is extended, such as to allow an operator to provide reduced pressure forces. Finally the disposition of the ram within the arrangement ensures better protection, in particular of the rod of the ram, in relation to the heat given off by the molten metal.