Lance for repairing refining vessel

Abstract

 A spray lance (12) for repairing refractory linings of refining vessels such as steel making converters comprises multiple concentric tubes to form a passage (18) for repairing material such as powder refractory and carbon powder, a passage (19) for a combustible gas such as oxygen and passages (20, 21) for feeding and returning a cooling fluid. A plurality of nozzles (16) are provided on a cylindrical surface and a front end, each consisting of two concentric pipes (16a, 16b) communicating with the passages (18, 19) for the repairing material and the combustible gas, respectively, thereby enabling the lance (12) to repair wider areas of inner walls of furnaces. In addition, without providing a nozzle (16) at the front end of the lance (12), the passage (18) for the repairing material is closed at its front end to form a cleaning opening communicating the passage (19) for the combustible gas, through which the combustible gas is jetted against the bottom of the furnace to clean accumulated adhesives on the bottom.

Description

[0001] This invention relates to a spray lance for a flame gunning device for repairing partially damaged portions of refractory linings of refining vessels such as converters for steel making, and more particularly to a lance for spraying melted or sintering or semisolid refractory against walls of vessels such as steel making converters, while cleaning raised bottoms of furnaces with accumulated adhering substances.

[0002] A method of repairing partially damaged portions of refractory lining of refining vessels such as steel making converters has been known as a repairing method disclosed in United States Patent No. 3,883,078.

[0003] This repairing method is referred to as wet gunniting process wherein pulverized refractory, pulverized solid fuel and oxygen are sprayed through a nozzle at a front end of a lance against a furnace wall surface of a refining vessel at a high temperature, for example, 1,350-1,500°C immediately after delivery or removal of melt steel from the furnace so that the damaged or consumed portion of the refractory lining is coated with the melted or semisolid refractory produced from the pulverized refractory by fuel combustion to join the melted refractory with the lining refractory.

[0004] The spray lance for use in the gunniting process has one end rotatably supported on a movable trolley 3 and the other curved end 1 to which is fixed a nozzle 2 directing in a radial direction of a lance tube axis (Fig. 1). With this arrangement, as only one nozzle 2 is used to repair the cylindrical wall of the refining vessel, the lance is required to have the curved end. Such a conventional spray lance serves only to repair a lining partially or locally and requires much time for repairing a wider area.

[0005] It is an object of the invention to provide an improved lance which eliminates the disadvantages of the prior art.

[0006] It is another object of the invention to provide a lance having a plurality of nozzles directing in various directions and selectively closable by plugs to be able to freely adjust the delivery amount, range and directions of the reparing material and combustible gas to effectively repair refractory walls in the most preferable condition.

[0007] It is a further object of the invention to provide an improved lance which is not only capable of repairing furnace walls but also cleaning adhesives accumulated on bottoms of the furnaces.

[0008] The invention will be more fully understood by referring to the following detailed specification and claims taken in connection with the appended drawings.

Fig. 1 is a perspective view of a conventional flame gunniting device and a lance as above mentioned;

Fig. 2 is a schematic sectional view of one embodiment of a lance according to the invention;

Fig. 3 is a schematic sectional view of another embodiment of a lance according to the invention;

Fig. 4 is a sectional view taken along a line IV-IV in Fig. 3;

Fig. 5 is a further embodiment of a lance according to the invention; and

Fig. 6 is another embodiment of a lance according to the invention.

[0009] Referring to Fig. 2 illustrating one embodiment of a lance according to the invention, the lance 12 consists of four concentric tubes to form four passages 18, 19, 20 and 21, the central flow passage 18 for flowing therethrough a repairing material (MgO and carbon powder) together with a carrier gas (N₂), the annular flow passage 19 surrounding the central flow passage 18 for flowing an oxygen gas (including more than 50% oxygen), and two outer annular passages 20 and 21 communicating with each other and surrounding the passages 18 and 19 for flowing feeding and returning cooling water. As an alternative, the central passage 18 may be used for the oxygen gas, and the annular passage 19 for the repairing material.

[0010] The lance 12 is provided in outer cylindrical surfaces and front end with a plurality of nozzles 16 respectively communicating with the central passage 18 and the annular passage 19. The nozzle 16 consists of an inner nozzle pipe 16a to form a passage communicating with the central passage 18 and an outer nozzle pipe 16b concentric to the inner nozzle pipe 16a to form a passage communicating with the annular passage 19. The nozzles 16 extend branched from the passages of the lance 12 away from an axis I thereof and the nozzle at the front end of the lance extends in the axial direction. In the embodiment shwon in Fig. 2, the nozzles on the cylindrical surfaces are inclined to the axis A of the lance in consideration of flow resistance of the powder flowing through the central passage 18. On the other hand, Fig. 3 illustrates nozzles 16 radially outwardly extending from a lance 12.

[0011] The lance 12 may be provided with only one nozzle 16 or a plurality of nozzles 16 as the case may be. Such a plurality of nozzles 16 are preferably arranged along at least one generator of the cylindrical lance. The lance with thus arranged nozzles is advantageous for repairing wider areas of a wall at a time, and is also applicable to local or partial repairing of the wall by plugging some of the nozzles as shown at 26 in Fig. 3. The use of the plugs 26 controls the directions and amount of the oxygen and repairing materials and sprayed areas to effect the repairing dependent upon positions and degrees of the damaged portions without any superfluous effort.

[0012] Fig. 5 illustrates a further embodiment of the invention, wherein a lance 2 includes a furnace bottom cleaning structure for removing adhesives on a furnace bottom. The adhesives would decrease a volume in a furnace and be resulting from insufficient slag removal as in an upper blown converter or the like requiring agitation gas to be blown into the converter through the furnace bottom. In order to effect the cleaning operation, a nozzle 16 is not provided at the front end of the lance and a front end of a passage 18 for the repairing material is closed at 24 to form a cleaning opening 23 which opens in an axial direction of the lance and communicates with the annular passage 19 for the oxygen gas. With this arrangement, when the lance is inserted into the converter, the cleaning opening 23 is in opposition to the furnace bottom, so that part of the introduced oxygen gas contacting the high temperature adhesives on the furnace bottom burns so as to melt the adhesives to ensure the cleaning of the bottom. As an alternative, if the central passage 18 is used for the oxygen gas, the cleaning opening 23 may be arranged at a location corresponding to the central passage 18.

[0013] An embodiment shown in Fig. 6 is substantially the same as that shown in Fig. 5 with exception of nozzles radially outwardly extend.

[0014] As can be seen from the above explanation, the lance according to the invention can effectively perform aimed repairing of linings of furnaces to bring good results in life, cost and rate of operation of the furnaces. In addition, the lance according to the invention has a remarkable advantage in hot repairing a refining furnace which is not only capable of repairing wider areas of a furnace wall at a time but also simultaneously cleaning a furnace bottom.

[0015] While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made therein without departing from the spirit and scope of the invention.

Claims

1. A lance for repairing walls of refining vessels, said lance including multiple concentric tubes to form a passage for flowing therethrough a repairing material to be sprayed and a passage for flowing therethrough a combustible gas, said lance comprising at least one nozzle consisting of two concentric pipes facing to the wall to be repaired and communicating with said passages for flowing the repairing material and for flowing the combustible gas, respectively.

2. A lance as set forth in claim 1, wherein said nozzle provided on a cylindrical surface of the lance is forwardly inclined relative to an axis of the lance.

3. A lance as set forth in claim 1, wherein said nozzle provided on a cylindrical surface of the lance is radially extending.

4. A lance as set forth in claim 1, wherein a plurality of the nozzles are provided along a generator of a cylindrical surface of the lance.

5. A lance as set forth in claim 1, wherein at least a pair of the nozzles are provided on a cylindrical surface of the lance at diametrically opposed positions.

6. A lance as set forth in claim 1, wherein said one nozzle is provided at a front end of the lance.

7. A lance as set forth in claim 1, wherein at least one plug is fitted in an end of at least the one nozzle for closing it.

8. A lance as set forth in claim 1, wherein said tubes are four concentric tubes, among which two inner tubes are for the repairing material and the combustible gas and two outer tubes are for feeding and returning a cooling medium.

9. A lance as set forth in claim 1, wherein a front end of the innermost tube of the lance is closed so as to jet only said combustible gas in an axial direction of the lance without jetting the repairing material.

Drawing