LU85630A1 - DEVICE FOR PROJECTING A REFRACTORY COATING FOR PROTECTING A LIQUID METAL TANK - Google Patents

Description

Device intended for the projection of a refractory protective coating of a liquid metal tank.

The present invention relates to a device intended for projecting a refractory coating on the walls of a liquid metal tank.

The invention particularly relates to a device 5 intended for the projection of a refractory lining, in particular on the interior walls of a tank of liquid metal, more particularly steel bags, ladles, distributors (tundish ) or the like. It is suitable both for the application of a permanent coating and for the projection of a basic protective coating, generally magnesian or for the repair of any other user refractory.

It is known to repair such reservoirs by trowelling, by projection or by application of a protective wear plate, namely plates to be fitted. This method has the disadvantage, however, that the repair of the refractory can only be carried out when the tundish is cold or, in any case, sufficiently cooled for it to be accessible.

According to another method of the prior art, an on-site molding is carried out by injection of a refractory. This method has the disadvantage, however, of using compositions having a water point which is too high and this results in the evolution of hydrogen which is harmful to the steel. On the other hand, this process is practically only suitable for large units and requires a significant investment in machines, jigs and molds. However, this technique has the advantage of applying both to permanent coatings and to protective coatings of all kinds.

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The object of the present invention is to provide a device for projecting a refractory lining which satisfies the safety and hygiene conditions.

Another object of the present invention is to provide a device which is also suitable for the application of a refractory lining in small units.

Another object of the present invention is to provide a device for projecting a refractory coating onto the walls of a tank of liquid metal, which makes it possible to apply both a protective coating and a permanent refractory coating.

Yet another object of the present invention is to provide a device for projecting a refractory lining, which can operate when the metal tank is not fully cooled, i.e. at temperatures ranging from up to 1000 ° C.

According to the invention, the device consists of a mobiJe gantry which is mounted on a mobile carriage and which is equipped with at least one means allowing vertical movement of a spray lance, as well as at least one means allowing a rotary movement of said spray lance.

Advantageously, the mobile gantry comprises a single control cabin for the automatic adjustment of the operations to be carried out and in particular of the movements * of the projection lance.

According to an embodiment of the present invention, the gantry can be equipped with several projection lances electrically controlled or, preferably, for safety reasons, pneumatically.

The projection lance is known per se and is advantageously constituted by a sliding lance 35 or telescopic guided in a sheath, which is controlled by a cable or a chain controlled from the outside. It advantageously consists of square section tubes in which are housed conduits bringing to the projection head the appropriate materials such as dry refractory material and water in the case where it is desired to carry out a refractory gunning. The lance can of course also be used to spray other fluids or chemicals.

* Said lance can also be adapted for the projection 10 of refractory materials put in a state of prefusion at the exit of the projection nozzle and this by various techniques in particular by plasma incandescence, by exothermy or torch.

In order to be able to easily reach all 15 points of the interior wall of a liquid metal tank, it is advantageous to be able to rotate the spray lance on its own axis, in a movement> back and forth. The means allowing this rotary movement of said spray lance can advantageously consist of a toothed wheel welded to the outer tube of the lance and driven in rotation by an electric or, preferably pneumatic, motor which ensures frequent changes direction of rotation.

In addition, the lance can undergo a movement of stopping, raising or lowering by means intended to provide a vertical movement of the projection lance which consists of a device with chains, cables or pneumatic or hydraulic pistons.

It is important to note that the device of the present invention can be used to coat a permanent refractory or protective coating the interior walls of a tank of liquid metal, at temperatures up to about 1000eC if said device is refrigerated. Being able to work at elevated temperature results in minimum hydrogen release due to the rapid evaporation of water under the effect of the heat of the object to be packed. The technique described is preferably used after having dislocated, that is to say after having emptied the distributors, bags or other containers of the frozen steel.

It should also be noted that the device of the present invention is suitable for any tank whatsoever for the purpose of producing a replacement coating or a coating for repairing a permanent refractory or protective, in basic, acid or aluminous.

The invention will be described in more detail in support of the following description of a preferred embodiment of the present invention, in support of the figures in which: - Figure 1 shows a side view of the device of the present invention; - Figure 2 shows a front view of the device of the present invention; 2o - Figure 3 is a plan view of the device of the present invention; - Figure 4 shows a projection head; and - Figure 5 shows the rotary connector lying at the top of the lance.

. With reference to FIGS. 1 and 2, the device consists of a mobile gantry 1 which can move on a mobile carriage 3 in a direction transverse to the direction of movement of said carriage 3. According to the embodiment described, the carriage comprises at least four rollers 2 allowing it to move on a rail 4 by means of a driving force delivered by a motor 5. The mobile gantry can move, as mentioned above, on the carriage in a transverse direction relative to the direction 35 of movement of the carriage and its movement is controlled 5 by a reducing motor assembly 7 shown in FIG. 3.

Said gantry 1 also comprises means 9 for 5 upward and downward movements and stop a telescopic projection lance 11 shown in the deployed state in Figure 1 and in the retracted state in Figure 2. Said means 9 advantageously consists of a chain device controlled by a motor 13 '10 (see FIG. 3) and carrying a support arranged with an anchoring device 15 secured to the lance 11.

The carriage 3 is also provided with a device for driving the projection lance 11 in rotation. This device advantageously consists of a toothed flywheel 15 17 secured to an outer sheath 19 of the telescopic projection lance. Since the telescopic lance has a square section, a gyratory movement of said guide 19 also allows the rotation of said lance 11 on its own axis. The sheath 19 2o is rotated via said flywheel 17 by means of a chain or a gear system 21 driven by a motor 23. It is also possible to use any similar or equivalent device which makes it possible to perform the same movement roundabout in both directions of rotation. The projection lance is advantageously equipped with a projection head 25 pivotally mounted on the end of the projection lance 11. The design of the projection head 25 is illustrated in FIG. 4. Its essential characteristic is the 30 fact that a rounded chamber 27 is arranged in its body which is partially filled with the projected material thereby protecting this body from wear under the effect of the admitted material. It is found that heads of this type or a contact material on material is able to resist without significant abrasion for significantly longer periods.

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In order to facilitate access to the various points of a most diverse liquid metal reservoir, the projection head 25 is advantageously orientable between 0 and 90 ° on the end of the projection lance 11.

In a particularly preferred manner, and according to the embodiment shown in the figures, the orientation of the projection head on the end of the lance can be controlled by a control device which will be described later.

The various flexible conduits identified by the reference 29 are taken up by return pulleys 31 and 33 which are suitably mounted on the gantry 1. The various flexible supply conduits are connected to the water supply devices, at 15 refractory material etc. which are not shown in the figures.

In the figures, two conduits are shown, "that is to say one for dry materials and the other for fluid materials, but other conduits can also be provided, in particular accessory conduits for the projection of a blasting material or for the circulation of a cooling fluid for example.

Advantageously, the mobile gantry is equipped with 25 powerful headlights 35 which make it possible to illuminate the interior of the liquid metal reservoir in order to facilitate the coating of the latter with an adequate refractory material. Advantageously, the mobile gantry is also equipped with one or more video cameras 30 making it possible to monitor the operations in progress from a distance.

The various movements to be carried out, that is to say the displacement of the mobile carriage 3, the displacement of the mobile gantry 1, the upward and downward movements of the lance 11, the gyratory movement of the latter, ./ 7 and possibly the orientation movement of the projection head 25 are controlled by a central computer not shown in the figures. The video cameras 36 allow an operator to follow the operations commanded by the central computer while facilitating manual correction or intervention if necessary.

Advantageously, the supply conduits of the drive motors which are preferably pneumatic * or hydraulic, as well as the cables of the headlights and cameras are guided on a deflection pulley 34.

Preferably, conduits in which circulates a cooling fluid and / or jets of fresh air are provided to cool the lance in operation. These devices allow work under conditions of interior temperature of the wall of the container which can range up to 1000 ° C. in particular.

With reference to FIG. 5, this represents a rotary connection with a hermetic seal which allows rotation of the lance 11 while preventing twisting of the supply conduits. Said rotary coupling advantageously comprises a fixed hollow element 41 provided with a male thread 42 on which the pipe carrying the material will be mounted, or a mixing head in which the solid material is mixed with water, and a rotary hollow element 43 25 secured to the lance 11 by means of the female thread 44.

The element 41 also includes a flange 45 with offset holes fixed to the anchoring device 15 driven in an upward or downward vertical movement.

The two elements 41 and 43 are rotatably assembled by means of two internal retaining rings 47 and 49 with frustoconical contact surfaces which feel fixed, respectively, to the element 43 and to the element 41, by screwing for example . The rotary connector according to the invention is advantageously traversed by a flexible pipe 51 which forms a hermetic passage chamber for the material to be sprayed. The parts 42, 47 and 49 8 advantageously consist of hard steel, the part 43 in bronze and the flexible hose 51 in rubber.

According to a particular embodiment of the present invention, the lance head 25 can also be controlled by a hydraulic or pneumatic double-acting piston acting on a rod connected to said head.

Preferably this head will be inclined at an angle of 33 to 45e with respect to the vertical, that is to say upwards in order to allow overlapping during work by successive circular portions of the head applying the refractory coating of bottom up.

The use of the device of the invention makes it possible largely to automate all the operations and to reduce the personnel to an operator of the machine and to a supervisor responsible for the safety and the observation of the progress of the operation on the video camera (s).

It is easily understood that the device of the present invention is suitable for the application of refractories in all types of liquid metal tanks such as steel bags, ladles, distributors and the like.

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Claims (17)

9 1. Device intended for the projection of a refractory lining on the interior walls of a liquid metal tank, characterized in that it consists of a mobile gantry (1) which is mounted on a mobile carriage (3 ) and which is equipped with at least one means (9) allowing a vertical movement of a projection lance (11) as well as at least one means (17, 21, 23) allowing a rotary movement of said lance projection (11). 2. Device according to claim 1, characterized in that the movement of the gantry (1) is carried out transversely relative to the direction of movement of the mobile carriage (3). 3. Device according to claim 2, 15 characterized in that the various movements are controlled by a central computer. 4. Device according to any one of the preceding claims, characterized in that the movements are controlled by pneumatic motors. 5. Device according to any one of the preceding claims, characterized in that it is equipped with several projection lances. 6. Device according to any one of the preceding claims, characterized in that the lance 25 pro jectiondl) is a telescopic lance. 7. Device according to any one of the preceding claims, characterized in that the projection lance (11) is a lance of square section which slides in a sheath (19) and the upward and downward movements of which are controlled by a cable. or a chain (9) controlled by an electric or preferably pneumatic motor (13). 8. Device according to any one of the preceding claims, characterized in that the means 10 allowing a gyratory movement of the projection lance 11 consists of a toothed flywheel secured to the telescopic lance or the sheath (19), the rotation of said flywheel being controlled by a motor (23) via a gear system (21) or a belt or chain (21). 9. Device according to any one of the preceding claims, characterized in that the lance (11) is assembled with the supply conduits (29) via * a mixing head and a rotary connector. 10. Device according to claim 9, characterized in that the rotary connector consists of a fixed hollow element (41) integral with the supply conduits or the mixing head and in a hollow element (43) integral with the lance ( 11) rotatable, the two elements (41, 15 43) being rotatably assembled by means of two internal retaining rings (47 and 49) with frustoconical contact surfaces which are respectively fixed to the hollow rotary element (43) and to the fixed hollow element (41), a flexible pipe (51) passing through said connection 20 turning right through. 11. Device according to any one of the preceding claims, characterized in that the projection head (25) mounted on the end of the projection lance (11) consists of a curved head having an enlarged chamber (27). 12. Device according to any one of the preceding claims, characterized in that the projection head (25) is pivotally mounted on the projection lance (11). 13. Device according to any one of the preceding claims, characterized in that the projection head (25) is controlled by a hydraulic or pneumatic double-acting piston acting on a connecting rod connected to said head. 14. Device according to any one of the preceding claims, characterized in that the various 11 supply lines for products such as water, dry matter, coolants, etc. are guided on return pulleys (31, 33). 15. Device according to any one of the preceding reven-5 dications, characterized in that the gantry is equipped with powerful headlights (35). 16. Device according to any one of the preceding claims, characterized in that the mobile gantry (1) is equipped with at least one video camera (36). 17. Use of the device according to any of the preceding claims for covering with a permanent refractory or protective coating the interior walls of a tank of liquid metal at temperatures up to 1000 ° C. / / '/ /. / h ^ \.