BURNER-LANCE UNIT

Abstract

A burner-lance unit (1) includes at least two gas connections (2a, 2b, 2c), a burner tube (3), and a lance tube (4) that is placed concentrically in the burner tube (3). The burner tube (3) and the lance tube (4) both have a gas inlet end and a gas outlet end (15). The lance tube (4) has a de Laval nozzle (4a) at the gas outlet end thereof. The de Laval nozzle (4a) is releasably connected to the lance tube (4). The burner tube (3) has a burner nozzle (3a) which is releasably connected to the burner tube (3).

Claims

1. A burner-lance unit for a furnace, for melting metal, the unit comprising: at least two gas connections into the furnace; a burner tube extending into the furnace and a lance tube extending into the furnace, the lance tube is arranged concentrically within the burner tube; each of the burner tube and the lance tube having a respective gas inlet end and a gas outlet end; a de Laval nozzle and a screwed connection for releasably connecting the de Laval nozzle to the lance tube; a cooling tube in which the burner tube is arranged concentrically: a burner nozzle of the burner tube encompassed by the cooling tube and a screwed connection releasably connecting the burner nozzle to the burner tube; the screwed connection between the burner tube and the burner nozzle comprises a first male thread arranged on the burner nozzle and extending concentrically around a longitudinal axis of the lance tube, and a first female thread arranged on the burner tube and interacting with the first male thread; and the screwed connection between the lance tube and the de Laval nozzle comprises a second male thread arranged on the de Laval nozzle and extending concentrically around the longitudinal axis of the lance tube, and a second female thread arranged on the lance tube and interacting with the second male thread.

2. The burner-lance unit as claimed in claim 1, further comprising: a cooling tube and at least two cooling-medium connections to which the cooling-medium passages are connected.

3. The burner-lance unit as claimed in claim 1, further comprising: at least one of an outside diameter and at least one of an inside diameter of the burner nozzle or of the de Laval nozzle has, at least one of an indentation or a projection which is configured to be brought into engagement with a key unit for releasing at least one the burner nozzle and at least one of the de Laval nozzle from the other nozzle.

4. The burner-lance unit as claimed in claim 1, further comprising a gas passage for a combustion enabling gas and located between the cooling tube and the burner tube.

5. The burner-lance unit as claimed in claim 1, further comprising: projections of an outside diameter of the burner nozzle configured for retaining the burner tube in the cooling tube in at least an almost clearance free manner.

6. The burner-lance unit as claimed in claim 1, further comprising: projections on an outside diameter of the de Laval nozzle configured for retaining the lance tube in the burner tube in at least an almost clearance free manner.

7. A metallurgical furnace, comprising a furnace chamber for melting of metal therein and having at least one burner-lance unit as claimed in claim 1, extending into the furnace, wherein the respective gas outlet ends of the burner tube and of the lance tube are arranged in a manner pointing the direction of the furnace chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIGS. 1 to 4 are to explain by way of example a burner-lance unit according to the invention and its use in a furnace. Therefore, in the drawing:

[0037] FIG. 1 shows a burner-lance unit in a three-dimensional view;

[0038] FIG. 2 shows a section through the hot end of the burner-lance unit according to FIG. 1;

[0039] FIG. 3 shows a rigid connection between a de Laval nozzle and a burner nozzle; and

[0040] FIG. 4 schematically shows a furnace having a burner-lance unit.

DESCRIPTION OF AN EMBODIMENT

[0041] FIG. 1 shows a burner-lance unit 1 in a three-dimensional view. In this case, the burner lance unit 1 has a hot end la and a cold end 1b. The burner-lance unit 1 has a plurality of gas connections 2a for the feed of fuel 8 and 2b and 2c for the feed of combustion enabling gas 9 or inert gas 9′. When the unit 1 is in lance mode, a first gas, here preferably in the form of a combustion enabling gas here, oxygen, is injected at supersonic speed alternately with a second gas, here inert gas, preferably in the form of nitrogen. In burner mode, fuel 8 together with combustion enabling gas 9, here preferably in the form of oxygen, are combusted.

[0042] The burner-lance unit 1 also has a cooling tube 6 shown in FIG. 2 with cooling-medium passages 6a at its radially outward periphery and cooling-medium connections 6b, 6c, wherein a cooling medium 7, especially water, can be fed to the cooling tube 6. The cooling medium 7 protects the burner-lance unit 1 against overheating. Heated cooling medium 7′ is discharged again from the cooling tube 6. In the region of the gas connection 2c, provision can be made for connections for measuring units, (not shown) such as temperature measuring units.

[0043] FIG. 2 shows a section II-II through the hot end 1a of the burner-lance unit 1 according to FIG. 1. Like designations identify the same elements as in FIG. 1. Now apparent in the cross-sectional view are the burner tube 3, the burner nozzle 3a which is arranged on the burner tube 3 by a first releasable connection 5, the lance tube 4 and also the de Laval nozzle 4a which is arranged on the lance tube 4 by a further second releasable connection 5. The releasable connections 5 in this case are constructed as screwed connections. The screwed connection between the burner tube 3 and the burner nozzle 4 comprises a male thread arranged on the burner nozzle 3a and a cooperating female thread arranged on the burner tube 3. The male thread and the female thread naturally interact. The male thread and consequently also the female thread extend concentrically around the longitudinal axis 17 of the lance tube 4. The screwed connection between the lance tube 4 and the de Laval nozzle 4a is constructed in a similar way. Also, the cooling-medium passages 6a provided in the cooling tube 6. A combustion enabling gas passage 6d is formed between the cooling tube 6 and the burner tube 3. A fuel passage 3b is formed between the burner tube 3 and the lance tube 4. Inside the lance tube 4, a lance passage 4b extends along the longitudinal axis 17 of the lance tube 4.

[0044] FIG. 3 shows the burner-lance unit 1 from FIG. 1 as seen in the direction of the longitudinal axis 17 of the lance tube 4. Like designations identify the same elements as in FIGS. 1 and 2. The burner nozzle 3a has projections 16 on its outside diameter. The de Laval nozzle 4a also has projections 16′ on its outside diameter. When exchanging the burner nozzle 3a and/or the de Laval nozzle 4a, the projections 16, 16′ are brought into engagement with a key unit and by means of this are rotated in relation to the burner tube 3 or the lance tube 4 and unscrewed. A new burner nozzle or a new de Laval nozzle can now be inserted and screwed down tight also using the key unit.

[0045] The burner tube 3 is retained in the cooling tube 6 in a clearance free manner or at least almost in a clearance free manner. For example, the projections 16 can be correspondingly dimensioned for this purpose. Similarly, the lance tube 4 is retained in the burner tube 3 in a clearance free manner or at least almost in a clearance free manner. For example, the projections 16′ can be correspondingly dimensioned for this purpose.

[0046] FIG. 4 schematically shows a furnace 10 with a burner-lance unit 1. Like designations identify the same elements as in FIGS. 1 to 3. The furnace 1 has a furnace chamber 11 which is enclosed by a furnace wall 12 and a furnace lid 12′. Located in the furnace chamber 11 is a molten metal 13 which is covered by a slag layer 14. The burner-lance unit 1 points by its hot end 1a in the direction of the furnace chamber 12, wherein the gas outlet ends 15 of burner tube 3 and lance tube 4, which in this case are only schematically indicated by a dashed line, also point towards the furnace chamber 11. The burner-lance unit 1 is in this case arranged on the outside on the furnace wall 12 or on the furnace lid 12′ and, preferably in a simple manner, for example by an arrangement on a pivotable or displaceable panel 18, which can be brought from the installed position into a maintenance position in which the burner nozzle 3a and/or the de Laval nozzle 4a can be exchanged.

[0047] FIGS. 1 to 4 only show one possible embodiment of the burner-lance unit, but various further constructional forms can be realized. The furnace 10 and the arrangement of the burner-lance unit 1 on the furnace 10 are also selected only by way of example.

LIST OF DESIGNATIONS

[0048] 1 Burner-lance unit

[0049] 1a Hot end

[0050] 1b Cold end

[0051] 2a, 2b, 2c Gas connection

[0052] 3 Burner tube

[0053] 3a Burner nozzle

[0054] 3b Fuel passage

[0055] 4 Lance tube

[0056] 4a De Laval nozzle

[0057] 4b Lance passage

[0058] 5 Releasable connection

[0059] 6 Cooling tube

[0060] 6a Cooling-medium passages

[0061] 6b, 6c Cooling-medium connection

[0062] 6d Combustible gas passage

[0063] 7 Cooling medium

[0064] 7′ Heated cooling medium

[0065] 8 Fuel

[0066] 9, 9′ Combustible gas or inert gas

[0067] 10 Furnace

[0068] 11 Furnace chamber

[0069] 12 Furnace wall

[0070] 12′ Furnace lid

[0071] 13 Molten metal

[0072] 14 Slag layer

[0073] 15 Gas outlet end

[0074] 16, 16′ Projection

[0075] 17 Longitudinal axis

[0076] 18 Panel

[0077] 34 Rib