Abstract:
This invention relates to a container for materials, preferably scrap iron for steel production and intended to be placed on a stand in a preheating station in order that the scrap iron shall be heated up to a high temperature. The container includes an essentially cylindrical upper part and a lower part comprising openable bottom halves. The upper part of the container (1) and each bottom half (4) comprise a gas-tight shell (2;15) and a load-carrying frame-work (5,6,7,8;10,11,12,13) positioned outside the shell (2;15) and functioning as a support for the gastight shell.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a container for materials, preferably scrap iron for steel production and intended to be placed on a stand in a preheating station in order that the scrap iron shall be heated up to a high temperature, and comprising an essentially cylindric upper part and a lower part comprising openable bottom halves. 
     Scrap iron is usually utilized as a main raw material when producing steel by means of the electric steel method. In this connection as a rule a preheating of the scrap iron is made before it is brought to a furnace for melting. The preheating of the scrap iron being in the container is made in order to save energy and is made by means of flue gases from the furnace in which the scrap iron shall be melted or by means of flue gases from a combustion chamber provided with a burner. 
     When heating scrap iron the flue gas temperature and the heating time up to now have had to be limited due to the fact that the scrap iron containers do not have such a construction that they are suitable to use if the scrap iron has a high temperature. It is true that the container itself is made of a strong steel plate with thick walls so that it can resist loads in high temperatures, but since the container itself is intended to carry loads, its strength is considerably reduced when scrap iron is heated up to a high temperature by hot gases. An essential reason why the temperature of the container should be high if the scrap iron temperature were high is that the cooling of known containers and the surrounding details is not satisfactory. As a rule this cooling is made by gravity flow of the surrounding air. 
     SUMMARY OF THE INVENTION 
     This invention intends to remove the problems with the known technique. This has been achieved by a container of the kind mentioned by way of introduction, which can be used for materials, such as scrap iron, for steel production and which can be placed on a stand in a preheating station in order to heat the scrap iron to a high temperature. The container includes an essentially cylindrical upper part and a lower part comprising openable bottom halves. The container includes a shell for enclosing materials such as scrap iron and a load-carrying framework positioned outside the shell and functioning as a support for the shell. The load-carrying framework comprises means constituting channels for circulating a cooling medium and the bottom halves are cooled by the load-carrying framework. 
     Due to the fact that the container has been given the above construction, conditions are created for an active cooling of the same by means of gas and/or a liquid. Due to that fact the scrap iron in the container can be heated to a high temperature without any considerable increase of the temperature in the surroundings of the container or in the load-carrying frame-work, whereby the strength of the load-carrying frame-work is not considerably reduced. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred embodiment of the invention shall be described more closely with reference to the accompanying drawings, in which 
     FIG. 1 shows a scrap iron container standing on a s a preheating station; 
     FIG. 2 shows a section of the scrap iron container along the line II--II of FIG. 1; 
     FIG. 3 shows horizontal sections through the scrap iron container on different levels; 
     FIGS. 4A and 4B show pictures of the container wall and adjacent parts; 
     FIG. 5 shows a principle diagram for cooling the container by a gas, for instance air; and 
     FIG. 6 shows a principle diagram for cooling the container by a liquid, for instance water. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIGS. 1-3 is shown a scrap iron container 1 having an essentially cylindrical, gas-tight shell 2 of a steel, which is resistant to high temperatures, and two projecting lifting taps 3 at its upper half for connection with a lift device. At its lower part the scrap iron container is provided with two bottom-halves 4, intended to be opened when the heated scrap iron shall be charged from the container. According to the invention the cylindrical shell 2 of this container can be made thinner than in known containers. For instance, the shell 2 can consist of a single metal plate as shown in FIGS. 4A and 4B. The primary purpose of the shell 2 is to keep the scrap iron in place during the heating. Due to the fact that the shell has been made thin, it has to be supported by a load-carrying frame-work. Thus, the container is provided with an outer load-carrying frame-work comprising an upper 5 and a lower 6 tubular collecting and distribution girder and other tubular connecting girders 7 and supporting bars 8. Therewith, both collecting and distribution girders 5,6 surround the shell 2 and are connected with each other by means of the girders 7 and the supporting bars 8, which are essentially vertically arranged in a great number and circumferentially spaced apart around the shell 2 at an angular distance to each other. The load-carrying parts 5,6,7 of the frame-work also have the purpose to function as channels for a cooling medium, whereby not only the load-carrying parts but also the jacket of the cylindrical shell 2 can be cooled. 
     In FIG. 4a and 4b there are shown two alternative embodiments regarding the relation between the shell 2 and the vertical channel 7 of.,cooling medium. In the embodiment according to FIG. 4A the channel 7 of cooling medium is connected with the shell 2 by means of the vertical supporting bar 8. When having this embodiment it could be suitable to place an isolation heat barrier in the space 9 between the shell 2 and the channel 7, whereby the heat losses are reduced and the radiation of heat from the shell 2 to its surroundings is prevented. 
     In the embodiment according to FIG. 4B the supporting bars 8 are taken away. In this case the tubular girders 7 constituting the channels of cooling medium function as a support for the shell 2 and rest directly against the shell. Due to that fact the shell can be cooled down by means of the cooling medium streaming or circulating in the tubular girder 7. 
     The lower part of the container 1, i.e. the bottom halves 4, is also intended to be cooled by a cooling medium and to be supported by a frame-work. For this purpose the two bottom halves 4 comprise an upper 10 and a lower 11 half-circular and tubular, collecting and distribution girder. Both girders 10,11 surround the shell 15 and are connected with each other by upper 12 and lower 13 connecting tubular girders and a centre box 14 The girders 12,13 are arranged so as to be circumferentially spaced apart around the shell 15 at an angular distance from each other. The side inner jacket 15a and the lower inner jacket 15c, of the bottom halves 4 are intended to rest on the upper girder 12 and the centre box 14, respectively. Under the lower girder 13, which is intended to function as a channel for a cooling medium, there is arranged a supporting plate 15b constituting the support for the container 1 when it rests against a container stand 16 during the heating period. 
     Between the inner jacket 17 of the container at its lower part and the upper girder 12 there are arranged a number of channels 18 through which a hot gas is intended to stream for heating the scrap iron in the container 1. This gas passes out through the outlet channel 19 in the container stand 16 after having passed the channels 18. 
     The cooling medium is supplied to and removed from the collecting and distributing girders 5,6 at the cylindrical part and the collecting and distributing girders 10,11 at the lower part of the container, respectively, by means of connecting pipes 20 and 21, respectively. For this reason there are two connections at the container 1 for both the pipe 20 and the pipe 21. The angular distance between ,the pipe connections 20 and 21 is essentially 90° (see FIG. 3). 
     The connecting pipes 20 and 21 are intended to be automatically connected with pipes 22 of cooling medium when the container 1 is placed in the container stand 16. 
     The container 1 can be cooled either by air and/or water as a cooling medium (see particularly FIGS. 5,6). When using air, it is blown by a fan via the distribution channels 24,22,21,20 to the distribution girders 5 or 6 and 10 or 11, respectively, on the container 1, whereafter the air is transported through the tubular girders 7 and 12,13,14, respectively, to the other distribution girders, in which holes for outlet of the air are directed to the inner jacket 2 of the cylindrical part and to the inner jacket 15a the bottom halves 4 and the supporting plate 15b at the lower part of the container. After the passage through the outlet holes in the distribution girders, the air is blown along the inner jacket and cools the same. 
     In this way a direct cooling of the lower part of the container and the load-carrying parts of the cylindrical part is achieved and also a directed cooling of the inner jackets of the container 1. 
     When having water as a cooling medium it is supplied via inlet pipes 24,20 and a three-way valve 25 to either the lower 6 or the upper 5 distribution girder of the cylindrical part, whereafter the water is distributed through the tubular girders 7 to the second distribution girder and via the return pipes 20a and 24a to a waste hopper in a cooling water system. When shifting the three-way valve 25, the cooling water circuits are automatically emptied. 
     The supply of cooling medium to the lower distribution girder 11 of respective bottom half 4 is made via the inlet pipes 24,21 and three-way valves 26,27. The cooling medium thereafter passes the tubular girders 13,12 to the upper distribution girder 10 and then via the return pipes 21a, 24a to a waste hopper in the open cooling water system. 
     When shifting the three-way valve 26, the upper parts of the cooling water circuits for respective bottom half 4 are automatically emptied. When shifting the three-way valves 26,27, the lower parts of the cooling water systems also are emptied by means of the pressurized air being let into the system via the conduit 20 and the three-way valve 27. 
     In the description tubular girders have been mentioned. With tubular girders is meant tubular girders having circular, square, rectangular or another cross section. 
     The invention is of course not limited to the mentioned embodiments but can be modified within the scope of the following claims.