GB2034605A - Spray device for repair of hot metallurgical vessels - Google Patents

Abstract

The device comprises a telescopically extensible water cooled lance (60, 89, 111) mounted on an adjustable tower carried by a manoeuvrable transporter (11), fed pneumatically with dry refractory repair material via hose (101), and the material is mixed with water in a chamber forming part of the lance, the pneumatic pressure and water pressure serving to deliver the mixed material out of the lance and to the repair site. <IMAGE>

Description

SPECIFICATION Spray device for repair of hot metallurgical vessels The present invention relates to a spray device for repair of hot metallurgical vessels such as converters for steel, the device comprising a transporter mounting a lance to spray the repair material.

A method and a device have been disclosed for automatically repairing the lining of a furnace, especially a furnace for carrying out the DH or RH degassing processes. In this a conveyor wagon mounts a vertical spray pipe which is liftable and rotatable so that a spray nozzle at the free end of the pipe can be inserted into the furnace, and its spray nozzle is brought into a position so that its spray direction corresponds to the worn, eroded, or spalled plate in the furnace. The spray pipe, known as a "firing tube", preferably has a non-circular hollow cross-section so that it cannot unintentionally rotate and can only be turned by rotating shifting means.

Such device is described in German patent applications 2617458 and 2657352. This device is selfpropelled, but would be difficult to operate in front of the very hot convertor aperture, since it is not possible to reach all the wear zones very quickly and with spatial precision. This device can also only convey a limited amount of the refractory material used for the repair. Because of the lateral immobility ofthe spray head, this device is unable to repair all the worn zones in the convertor from one fixed base point, and in order to complete a repair the device would usually have to be moved by means of the conveyor, necessitating complicated handling in front of the hot converter and thus extending the repair time.

A further disadvantage of said known apparatus is that the water added to the refractory material is admixed in the feed hose, i.e. before the lance. The friction of the wetted refractory material against the rubberwall leads to plug formation and makes continuous feeding difficult. This also affects the concentration of the mixture of solid and water and reduces the durability of the repair.

In a different method for such repairs moist refractory material is used instead of dry material mixed with water in the apparatus, but effective continuous feeding cannot be achieved with known pressure feed vessels, since the pre-wetted material accumulates on the vessel walls and makes the device partly unusable. Combination with one of the rotary conveyor machines which allow for accumulations, as described in Swiss patent No. 579697, is also not possible.

The problem on which the present invention is based is that of providing a spray device which enables repair to be effected in very short operating times, occasioned by corresponding mobility of the device, applicable for any size of converter, adaptable to the amount and nature of the material, reliable in operation, with shielding from the effects of heat.

In accordance with the invention we provide a spray device for hot repair of metallurgical vessels comprising a transporter mounting a pivotable telescopically extensible spray lance which is water cooled, with a hose for feeding refractory material for the repair from a separate material station to a mixing chamber associated with the lance, characterised in that the mixing chamber for adding water to said material is disposed in the lance interior.

One embodiment of the device provided by the invention will now be described with reference to the drawings. In these: Figures 1, la show a spray device ready for operation as seen from the front, with the spray lance extended (Figure 1), and as inserted into converters of various sizes (Figure 1 a), Figure 2 is the representation in Figure 1 in plan view, Figure 3 is part of the side view of the device in Figure 1, with the lance partly extended, partly in section and with parts broken away, Figure 4 is a longitudinal section through the connection between the material feed hose, the mixer for added water, and the lance.

Converters are used for producing mild steel by the air-blowing method. Such converters are pearshaped steel vessels lined internally with refractory bricks. When the melting temperature of the steel causes damage to the internal lining of such converters, or when this protective layer no longer has the requisite thickness, the converter must be repaired.

This is effected by a sprayer while the converter is hot. Very high mechanical and operational demands are therefore made of such spray devices. Spatially the device must be very mobile, it must be capable of movement very quickly and accurately into the converter, with immediate starting of the repairs.

The parts of the lance must be cooled, and their mounting such that parts softened by heat are immediately brought back to their original shape when retracted, otherwise they may jam when next extended.

With the plant represented in the drawings, Figure 1 a shows a converter, with various sizes and shapes represented at 3, 4, 5 and 6. This shows how mobile in particular the spray lance must be in order to each accurately and repair any position in the usual converters with minimum expenditure of time. A spray device 8 (Figure 1) is shown movable along a floor 10. It comprises a transporter 11 with an undercarriage 13 movably mounted on two pairs of rollers 15 and 16 (Figure 3). The pair of rollers 15 are pivotable, as shown in Figure 2, by a swivel fork 17 (Figure 3) with the aid of a frame 18, so that the transporter 11 can be moved with ease to the required position. The frame 18 also acts as a traction coupling link for transporter 11.

To undercarriage 13 is affixed a chassis 20 provided with lifting plates 21 whereby the transporter 11 can be raised by a crane, as shown in Figure 1. On the chassis 20 is a rotary tower 23 with a swivel saddle 24. Figure 3 shows the construction of the rotary tower 23. Under the swivel saddle 24 is a travelling saddle 25 to which is affixed an outer cog 26. The swivel saddle 24 carries an inner cog 27 mounted in roller bearings in outer cog 26. A bracket 30 on swivel saddle 24 is provided with a hydraulic motor 31 which drives a pinion 32 in engagement with the teeth of the outer cog 26. The bracket 30 also carries support plates 34 used to mount pivotally a rotary head 35. The mounting is by means of a pivot journal 37 and also by a piston and cylinder unit. This unit has a cylinder 39 which by means of a plate 40 and journal 41 is pivotally mounted on the support plates 34.A piston rod 43 in the unit, also provided with a plate 44, is correspondingly pivotally affixed by means of a journal 45 to the frame of the rotary head 35, so that through movement of piston rod 43 in cylinder 39 the rotary head 35 with the entire structure can be pivoted up and down about the axis of pivot journal 37, as indicated in Figure 1.

To the chassis 20 is also affixed a longitudinal beam 47 with a rack 48 wherein engages a pinion 49 driven by a hydraulic motor 50. The longitudinal chassis beam 47 is also provided with four rails 57 wherein, as seen, pairs of rollers 58 support the travelling saddle 25 with the entire upper structure.

On driving the hydraulic motor 50, this together with the saddle 25 and its superstructure move in the direction of the rack 48 or the rails 57, which enables the spray lance to move transversely of the converter's longitudinal axis. Simultaneously or staggered with this linear motion the saddle 24 with its superstructure can naturally be rotated relative to saddle 25 by means of the hydraulic motor 31, thereby to bring the lance extremely quickly into the desired spraying position.

From Figure 2 it is seen that the chassis 20 is used to hold a water tank 53 which supplies both cooling waterforthe lance and also mixing water (two independent pumps), as well as a hydraulic fluid tank 54 for driving the hydraulic units such as the hydraulic motors, the piston and cylinder unit, and other drives mentioned below. These media are conveyed by pumps which as shown are actuated by electric motors. The elements needed for controlling the plant are shielded from the direct radiation of the converter in a control eiement cabinet 55.

The spray lance, which is telescopically constructed so that it can be taken accurately and at the last moment into the converter interior, has a radially outermost lance 60 of square tube section.

This section is based on strength considerations, taking into account its inherent weight, moment of inertia, and the requirements of support, aiming, cooling and driving. The outer lance 60 has a double casing 61, through which water 62 flows as the cooling fluid. Both the underside and upper side of outer lance 60 have a hydraulic motor 64 affixed in a swivel fork 65. These forks 65 are pivotable about swivel shafts 66. The forks 65 also carry friction rollers 68, driven by the hydraulic motors 64. The free ends of the swivel forks 65 are resiliently held together by a bolt 69 and set of springs 70, in order to bring the friction rollers 68 into correspondingly positive engagement with the lance 60.When the hydraulic motors 64 are put into operation, the outer lance 60 can thus be moved axially. in the area of the front and rear ends of the rotary head the outer lance 60 is also carried by eight support rollers 72 in each fork 73, as seen from Figure 3.

A base portion 75 of the rotary head 35 forms part of a stand housing 76,77 which does not rotate itself but is pivotally connected with the pivot journals 37 and 45. The stand housing 76, 77 is laterally enclosed. Between the lateral closures of the stand housing 76,77 lies the rotary head 35, rotatable through at least 360" about the longitudinal lance axis 87 and having in its casing an access aperture with a cover 79. The outer lance 60 is movably mounted in the rotary head 35 by means of rollers 72 held in lugs 73. Rotation of the head 35, which movement is transmitted through rollers 72 to the outer lance 60, is effected by a hydraulic motor 84.

This drives a pinion 85 engaged with the outer teeth of a cog 80. The cog 80 forms part of a roller bearing 81 whose inner rig 82 is connected to the side-wall of the housing 76,77, (ball bearing slewing gear). A simiiar mounting for the rotary head 35 is found at the other end thereof.

In addition to the outer lance 60, the telescopically constructed lance has a correspondingly formed round inner lance 89 connectable by a coupling member 91 at whose free end is disposed a spray nozzle 90 at an angle of 45" for example to the longitudinal axis 87, as shown by Figure 3. As seen, the inner lance 89 can consist of several parts. The free rear end of inner lance 89 is affixed by clamping means 93 whose construction is shown in principle in Figure 4. At the rear end of the clamping means 93 is a mixing chamber 94 having a water feed ring 96 for supplying mixing water to the lining material which has been pneumatically conveyed in the dry state. Inner lance 89 is supported by guiding and aligning rollers 97. These are mounted inside the outer lance 60.They are used not only for guiding the inner lance 89 as it moves in and out but also have a straightening function as the possibly deformed inner lance 89 is retracted. The clamping means 93 is in turn supported by rollers 99 in the inner casing of the outer lance 60, to ensure ready movement of inner lance 89 in the outer lance 60.

The solid material to be sprayed into the converter is fed from a storage station, not shown, by pneumatic transport through a feed pipe 101 into the device 8. The pipe 101 is moved with the inner lance 89, and therefore has its own pipe drive 102 which, actuated by hydraulic motors (not shown) acts on two drive rollers 103 in frictional engagement with the outer surface of pipe 101. As Figure 3 shows, these drive rollers are each held in pivot levers and spring loaded to ensure optimum force transmission to the pipe 101. Through the thrust they thus also drive the inner lances 89 and 111.

In order that the extension and retraction of the lances, and also the rotation and displacement of travelling saddle 25 and of swivel saddle 24together with the entire superstructure, shail not be hindered by hoses which act as connecting members for cooling and mixing water and hydraulic oil, hose drums, four in number, are disposed at the rear part of the outer lance 60 and act as a counterweight.

They are provided with corresponding drives and braked free-wheels so that the hoses can always be kept in a taut state.

As Figure 4 shows, the interchangeable water feed ring 96 is provided with a spray water conduit 108.

The water flows through apertures 109 into the mixing chamber, where it is mixed with the dry lining material supplied through the pipe 101. By suitable disposition of these apertures 109 it is possible to impart a forwardly directed rotary motion to the solid material, thereby to achieve an optimum mixing effect.

To make the device also adaptable to varying demands, the inner lance 89, the ring 96 and the pipe 101 can be replaceable. When using smaller diameter inner lances, the appropriate inner lance 89 is held by support cams 112 in an outer lance 111, while on using a larger diameter inner lance the lance 89 is omitted, and the free end of the inner lance 111 is directly affixed in the clamping means 93 and is used to supply material.

Through the ability to rotate the spray lances about their longitudinal axes, to move them longitudinally, to rotate them about a vertical axis, to swivel them with the aid of the piston/cylinder unit 38, and to move them along rails 57, the described spray device is movable so that converters of standard shape can be traversed and lined in a very short time, while the reduced periods of operation and the design of the plant substantially preclude the possibilities of jamming and damage to the device through the intense heating effect.

Claims (16)

1. A spray device for hot repair of metallurgical vessels, comprising a transporter mounting a pivotable telescopically extensible spray lance which is water cooled, with a hose for feeding refractory material for the repair from a separate material station to a mixing chamber associated with the lance, characterised in that the mixing chamber for adding water to said material is disposed in the lance interior.

2. A spray device as in Claim 1, characterised in that the mixing chamber is formed as an annular nozzle with water jets directed towards the axis of the annulus.

3. A spray device as claimed in Claim 2 in which the said jets are arranged to impart to the water a rotary and axial movement towards the lance tip.

4. A spray device as claimed in any preceding claim in which the mixing chamber is clamped to a telescopically extensible lance part for movement therewith.

5. A spray device as claimed in any preceding claim wherein the lance is mounted on a rotary tower which is displaceable in two directions on the transporter for spatial positioning of the lance relative to the transporter.

6. A spray device as claimed in any preceding claim wherein the transporter has wheels pivotale through at least 90 , and the transporter chassis is formed as containers for water and hydraulic oil.

7. A spray device as claimed in Claim 6, characterised in that the wheels are formed as rollers.

8. A spray device as claimed in Claim 5 in which the rotary tower comprises a head pivotable about a horizontal axis.

9. A spray device as in Claim 5, in which the rotary tower is movable longitudinally or transversely on the transporter by means of a hydraulic drive.

10. A spray device as in Claim 5, in which the rotary head includes rollers for longitudinal guidance of the radially outermost lance part.

11. A spray device as claimed in any preceding claim in which the radially outermost lance pipe comprises a double-walled square section pipe movable axially by a hydraulic drive.

12. A spray device as in Claim 22, in which the drive for the square section pipe includes two oppositely disposed hydraulic motors provided with friction rollers for positive engagement with the square section pipe and wherein each hydraulic motor group is affixed in swivel forks whose free ends are joined together through a spring member.

13. A spray device as in Claim 5, wherein at least one drum is affixed to the rotary tower to receive hose-like fluid conduits.

14. A spray device as in Claim 11 wherein the square section pipe is provided with radially disposed guide rollers fortelescopically supporting an inner lance pipe.

15. A spray device as claimed in any preceding claim wherein the lance is rotatable through at least 360 about its longitudinal axis.

16. A spray device for repairing hot metallurgical vessels, substantially as described with reference to the accompanying drawings.