The drying process requires very slow and uniform increase in temperature with regulated rate depending on the ladle capacity. The heating rate in the drying process is within the range of a few to several °C/h. The heating process proceeds at conside- rably higher heating rates amounting to over 100°C/h. Up to present, a number of met- hods for drying and heating of the ladle have been developed.

From the Polish patent no 158 841 the method is known for drying of the fire- proof steel ladle lining as well as the station for drying the fireproof steel ladle lining, a device utilizing the enthalpy of the combustion gases arising from another source.

The reported method consists in that into a newly lined ladle the steel ingots of the ini- tial temperature of 800°C are introduced and kept in the ladle under untight covering until the temperature reduces to 450°C, followed by replacing the ingots by successive ingots of high temperature, the drying process being conducted until the temperature outside the armour reaches 60° to 80°C.

Another method for drying and heating of the ladle with the use of a device equipped with a recuperator was described by H. Kroger and W. Schnabel in"Steel Times"10 (1988).

Also a device is known for drying and heating of the-steel ladles with the use of self-recuperative burner, where heating of the ladle occurs through the outflow nozzles of the gaseous fuel and air situated in the ladle interior at its bottom. Temperature uni- formity is obtained owing to the multi-hole nozzles applied.

The disadvantages of such a solution include a high leakage amounting to 10- 30 %, accompanied by unsatisfactory gasodynamics of the burner. Further inconve- niences include a possibility of damaging the device due to improper placement of the burner relative to bottom of the ladle, as well as a possibility of using a burner to the ladle of only one capacity. In addition, the process of drying the ladle is performed in an unsatisfactory way due to the local overheating of the ladle bottom.

The method for drying and heating of the casting ladle lining with the use of self-recuperative burner consists in that the ladle situated in the drying and heating station is aligned horizontal, followed by pushing towards each other the cover and the ladle to close it tight. Then, the substrates outflow rate at the outlet of the self-re- cuperative burner situated in the cover is settled within the range of 5 to 120 m/s, followed by turning the burner on, and, in the case of the newly lined or regenerated ladles the drying process is conducted at lower substrates outflow rates and at the heating rate amounting to 3-10°C/h until the settled temperature of isothermal heat resistance is reached. Then, the heating is restarted using higher substrates outflow rates until the reached final temperature of heating the ladle does not exceed 1300°C, at which the burner is automatically turned off. In the case of the exploited ladles the drying stage is omitted, and only the heating is performed at higher rates of the sub- strates outflow from the burner. After heating, the ladle is moved to the casting station by means of standard mechanical tools.

The reported method for drying and heating of the ladle can be conducted also in other modifications, in which the ladle is tilted from horizontal plane at the angle not larger than 30°, and pushed close to the appropriately positioned cover in order to clo- se tight, or the ladle mounted vertically is moved to the cover previously hung on the stands of various construction. The remaining stage of the drying and heating process is conducted according to the procedure described above.

A device for drying and heating of the casting ladle according to the invention contains a self-recuperative burner with the attached gas and air pipes, and the com- bustion gases offtake. The burner consisting of the air nozzles aligned concentrically with the inner gas nozzle, not whirling the gas jet, is settled in the cover, whereas at its outlet situated in plane of the cover closing the ladle a pipe-shaped combustion stabi- lizer is installed. From the inside, the cover is lined with a fibre stable to heat, levelling the irregularities on the entire surface of the ladle lining, the fibre being the seal of an interior of the ladle during the drying and heating processes. The cover is mounted to the base settled on the foundation, whereas the ladle is pushed close to the cover by means of a car with road wheels positioned on the steel rails. On the car are mounted a loose wheel unit and power wheel unit combined with a reducer driven with an elect- ric motor. On the wheel units a turn-table with the ladle is placed. The power wheel unit has a wheel with chain teeth in mesh with a toothed sector of a pin rack aligned concentrically with the raceway which constitutes an integral part of the turn-table. The turn-table has two walls situated perpendicularly relative to each other, one of which being a base to settle the ladle, whereas the other has the pins of different heights constituting a support of the ladle in the service position, the pins enabling horizontal alignment of the conical surface of the ladle jacket during its displacement towards the cover. In the service position the turn-table moves around making the upper surface of the ladle align parallel to the cover, whereas the car displaced by means of a hydraulic cylinder fixed with a shackle to the base and with a piston rod to the holder mounted to the frame of the car makes the ladle meet with the cover when moving towards the co- ver, thus closing tight the heating system.

In a modification, the ladle is placed on the seat in the car by means of a pin system and a screw gear. The seat has the pins of different heights constituting a sup- port of the ladle in the service position which enable to align the conical surface of the ladle jacket horizontally on pushing the ladle close to the cover. The screw gear enab- les the correction of the lack of parallelism of the cover surface and the upper surface of the ladle.

In another modification intended for the stoppered ladies, the cover is mounted to the stand settled on the foundation, whereas on the stand a ladle hoist is fixed, which lifts the ladle towards the cover or falls the ladle down. The hoist is equipped with the rollers settled on the rails, the rollers tread and rolling surface of the rails being prismatic in shape. The hoist is set in motion by means of a piston rod of the hydraulic cylinder, whereas the ladle is displaced onto the hoist via the car moving on the rails.

In the case of drying and heating of the so called lip-pour ladle (tilting ladle), the ladle is placed vertically, and the cover is fixed to a rotary outrigger suited to make 90° turn in horizontal plane. The outrigger is connected to a movable part of the stand which moves in vertical plane, whereas an immovable part of the stand settled on the foundation has two sets of rollers sliding a movable part of the stand. In an immovable part of the stand a seat is situated where the ladle is placed. The pipes supplying gas and air to the burner are fixed to the burner, and in the area not subjected directly to heat emissioned from the ladle these pipes are connected with the installations by fle- xible pipes enabling to turn the cover as well as to move the cover upward and down- ward. The combustion gases offtake above its bend has a telescope connection enab- ling the turn as well as the upward and downward motion. The upward and downward displacement of a movable part of the stand is accomplished by means of the hydrau- lic cylinder.

The method according to the invention ensures the heating of the ladle to be uniform, controlled and in compliance with technological requirements, being accom- panied by reduced emission of gaseous NOX contaminations to below 38 ppm, i. e.

20.1 g/GJ, and of CO to below 28 ppm, i. e. 9.1 g/GJ. The process conducted accor- ding to the method described ensures to obtain the castings without structural defects, and to prolong time between overhauls of the ladle lining.

A device according to the invention enables drying and heating of the ladles of various charge capacities and different constructions, such as among others the stop- pered ladles and lip-pour ladles, and also allows to recover heat from the combustion gases, which may be utilized for drying and heating of the charge material for melting.

The object of the invention is shown in the drawings. Fig. 1 presents a vertical projection of the device for drying and heating of the casting ladle, where the cover is placed on the base and the ladle is located on the turn-table in the starting position.

Fig. 2 provides the same solution, but in the service position, Fig. 3-a vertical projec- tion of a device with the ladle placed on the seat in the service position, Fig. 4-a ver- tical projection of a modified device with the cover placed on the stand, and the ladle equipped with a stopper mechanism located on the fork hoist, Fig. 5-a vertical pro- jection of the device with the cover lifting mechanism and the mechanism of the cover turn to 90°, where the cover is mounted to the rotary outrigger, whereas Fig. 6 shows the same modification in a horizontal projection.

As shown on the drawing in Fig. 1 the self-recuperative burner 1 with the gas and air supplying pipes as well as the combustion gases offtake is mounted in the co- ver 2 lined with kaolin fibre 2a stable to heat, playing the role of a seal of an interior of the ladle 3 during its drying and heating. The cover 2 is mounted to the base 4 settled on the foundation. A car 5 with the road wheels 6 is placed on the rails 7. On the car 5 is mounted a loose wheel unit 8 and a power wheel unit 9 coupled with a reducer 12 driven by an electric motor 13. On the wheel units 8 and 9 a turn-table 17 is placed.

The power wheel unit 9 has a wheel with chain teeth 14 in mesh with a toothed sector of a pin rack 15 aligned concentrically with the raceway 16 which constitutes an integ- ral part of the turn-table 17. The turn-table 17 has two walls situated perpendicularly relative to each other, one of which being a base to settle the ladle 3, whereas the other has the pins 18 of different heights constituting a support of the ladle 3 in the service position, the pins enabling horizontal alignment of the conical surface of the jacket of the ladle 3, which ensures the work safety during transportation of the ladle 3 by the car 5 towards the cover 2.

Fig. 2 shows the ladle 3 after turning which makes the upper surface of the ladle 3 align parallel to the cover 2 and reaching contact with it. The car 5 is driven by means of a hydraulic cylinder 19 fixed with a shackle to the base 20 and with a piston rod to the holder 21 mounted to the frame of the car 5.

Fig. 3 illustrates the ladle placed on the seat 22 settled on the car by means of a pin system 23 and a screw gear 24. The seat 22 has the pins 18 of different heights constituting a support of the ladle 3 in the service position, and enabling to align the conical surface of the ladle jacket 3 horizontal pushing the ladle 3 close to the cover 2. The screw gear 24 enables the correction of the lack of parallelism of the cover sur- face 2 and the upper surface of the ladle 3.

The drying and heating station, shown in Fig. 4, for the casting stoppered ladles has a self-recuperative burner 1 with the attached gas pipe, air pipe and combustion gases offtake-33,34 and 35, respectively. The burner 1 is settled in the cover 2 lined with kaolin fibre 2a, stable to heat, constituting a seal of an interior of the ladle 3 during its drying or heating. The cover 2 is mounted to the stand 25 settled on the foundation, whereas on the stand 25 a fork hoist 26 is attached, which lifts the ladle 3 towards the cover 2 or downward. The hoist 26 is equipped with the rollers 27 which are placed on the rails 28, the rollers tread 27 and rolling surface of the rails 28 being prismatic in shape. The hoist 26 is set in motion by means of a piston rod 27 of the hydraulic cylin- der. The ladle 3 is displaced onto the fork hoist 27 with the aid of the car 30 moving on the rails 32, started by means of a driving gear 31.

In Fig. 5 a station is shown for drying and heating of the so called lip-pour ladle in vertical position. The self-recuperative burner 1 with the attached gas, air and com- bustion gases pipes, 33,34 and 35, respectively, is settled in the cover 2 lined with ka- olin fibre 2a constituting a seal of an interior of the ladle 3 during its drying or heating.

The cover 2 is mounted to the rotary outrigger 36 suitable to make a 90°-turn in hori- zontal plane. The outrigger 36 is attached to a movable part of the stand 37a which moves in vertical plane. An immovable part of the stand 37 is fixed on the foundation.

It contains two sets of the rollers 38 sliding a movable part of the stand 37a. In an im- movable part of the stand 37 is settled a seat 37b where the ladle 3 is placed. The gas pipe 33 and air pipe 34 are fixed to the burner 1, and in the area not subjected directly to heat emissioned from the ladle 3 the pipes 33 and 34 are connected with the instal- lations by flexible pipes 33a and 34a enabling to turn the cover 2 as well as to move the cover upward and downward. The combustion gases offtake 35 above its bend has a telescope connection enabling the turn as well as the upward and downward motion. The upward and downward displacement of a movable part 37a of the stand 37 is accomplished by means of the hydraulic cylinder 39.

The method for drying and heating of the casting ladle lining is described in the example which takes into account the principe of operation of a device for drying and heating of the casting stoppered ladle made according to Fig. 4 of the drawing.

The self-recuperative burner 1 with the attached gas, air and combustion gases pipes, 33,34 and 35, respectively, is settled in the cover 2 lined with kaolin fibre 2a, whereas the cover 2 is mounted to the stand 25 settled on the foundation. The ladle 3 placed on the car 30 is displaced towards the device for drying and heating, followed by placing the ladle onto the fork hoist 26, lowered to the extreme lower position, used to lift the ladle 3 towards the cover 2 aligned horizontally relative to the outrigger of the stand 25 thus making the ladle 3 close tight. Upon closing, the ladle 3 there occurs an ignition of the burner 1 working in two operation modes, and the drying process of the ladle lining 3 starts at the heating rate ranging from 3 to 10°C/h, which corresponds to the first programmed operation mode of the burner 1. Upon reaching the temperature of isothermal heat resistance inside the ladle, usually close to 200°C, the drying pro- cess is stopped, and operation of the burner 1 is switched to the second of its bistable operation modes, the heating being then restarted at higher rate of the substrates out- flow from the burner outlet, preferably amounting to 60-120 m/s. The ladle lining 3 is heated until the desired temperature is reached, then the hoist 26 is lowered to its extreme lower position, the ladle 3 is removed from the station by the car 30, and by means of standard mechanical tools, e. g. ladle crane, the ladle 3 is displaced to the melt station.