DE2937303A1 - UNIT WITH BLOWING NOZZLES, CALLED LANCK HEAD FOR BLOWING GASES, ON OR IN A BATH OF MOLTEN METAL - Google Patents

Description

Unit with blowing nozzles, called "lance head", for blowing gases on or in a bath of molten metal.

10

15th

The invention relates to units with one or more blowing nozzles for blowing gases, with or without solids content, at least at the speed of sound, on the surface or below the surface of a bath of molten metal in a container, or for blowing these media into a furnace containing a molten bath , especially of molten iron.

In particular, the invention relates to units with one or more blowing nozzles for blowing oxygen, with or without a solid content, onto the surface of the molten metal in a steelworks converter which is used for steel production.

The units mentioned work in close proximity to molten metal and must therefore withstand high temperatures.

03001 A / 0722

Normally, the gas is supplied to the blower nozzle unit through a tube which is usually "blower lance" is called. The unit with the blower nozzle (s) forms the end of the blower lance and is usually Called "lance head".

The lance head is the unit that ends the lance.

To simplify the description, the above terms are used below.

In individual applications it is possible to use an uncooled blowing lance. In the case of nowadays Very frequent use of blowing lances for the production of steel in the converter by means of oxygen is not known that the use of uncooled blowing lances was possible. In all known cases, the steel mills use cooled blowing lances.

The lance head according to the invention relates only to cooled blowing lances, which are usually also provided with cooled lance heads.

The cooled blowing lance usually consists of several concentric or nested tubes which the individual chambers form the supply and discharge of the cooling water and the chamber or chambers for gas supply.

For a better understanding of the invention, the accompanying FIG. 1 shows an example of a known embodiment

25- of a lance head:

The known lance head consists of an outer base (1) and an inner base (2) which are passed through the blower nozzle or Blowing nozzles (3) are connected. The interior is filled with cooling water. This cooling water space is the direct one Continuation of the water chambers of the blow lance. The attachment of the lance head to the blowing lance (6) must be done by a process that guarantees absolute tightness, usually the lance head welded on.

O300U / Q722

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The known lance head is thus a welded or cast unit which inseparably connects the actual closure of the blower lance, i.e. the water chambers (4) and (5), with the blower nozzles (3). ι

This construction therefore requires constant and complete cooling.

Usually the complete lance head, but at least the outer base and the nozzles, are made of copper, that is to say a metal with high thermal conductivity but low mechanical strength and a relatively low melting point.

If the lance head is welded to the blowing lance , it is only possible to change the blowing characteristics by cutting off the entire lance head and welding on another lance head with changed nozzle cross-sections or nozzle angles. This changeover requires intervention in the cooling circuit.

It is therefore impossible to change the blowing characteristics as quickly as possible with the known lance head design.

It is obvious that a lance head can only be used as long as its water chambers do not show any noticeable leakage. In the event of a leak, the lance must be taken out of service immediately, which disrupts the metal processing cycle.

It has been shown that the well-known lance head construction has disadvantages that have a very negative effect on the service life:

- In a lance head with several nozzles, it is very difficult to guide the coolant in such a way that the entire surface exposed to heat is cooled evenly and sufficiently. Often there is a risk of local overheating which causes burnouts.

- The air nozzles connect the outer parts and the inner parts which are very different from heat loads and thus Are subject to thermal expansion. The tensions that arise

fatigue the material and create cracks. 03001 h / 0722

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- The gas, which usually emerges from the nozzles at supersonic speed, creates a negative pressure in front of the nozzles which causes the "suction" of thrown particles. These particles grind the cooled one Soil between the nozzles and cause breakthroughs.

The invention is based on the one hand to limit the risk of breakthroughs to a minimum, on the other hand, to enable an immediate change in the blowing characteristics.

The unit with blow nozzles, i.e. lance head, according to the The invention is characterized in that the part carrying the nozzle (s), hereinafter referred to as the nozzle base, is independent of the actual end of the lance, which alone forms a water chamber.

FIG. 2 shows an example of a possible embodiment of the lance head according to the invention.

The nozzle base (1) with the nozzles (3) can only be fixed with mechanical means, e.g. screws or wedges actual lance end (2) connected. It can be detached from it at any time without any intervention in the water chambers. The lance end (2) is the extension of the blowing lance (5) and is connected to it in such a way that absolute Tightness is achieved. The end of the lance (2) is preferably welded on.

The invention has the following advantages:

- The nozzle base can be changed quickly and easily, even directly before the blower lance is put into operation, without interfering with the water chambers. It is thus possible to change the blowing characteristics immediately Insertion of a nozzle base with modified nozzle cross-sections or nozzle angles.

- The water chamber at the end of the lance has a very simple shape, which ensures even cooling at every point is achieved without dead corners.

03001 U / 0122

ORIGINAL INSPECTED

- Fatigue of the material of the cooled lance end due to differential thermal expansion can practically no longer occur.

This significantly reduces the risk of breakthroughs in the water chamber and the service life of the lance head increased accordingly.

- The independence of the nozzle base from the actual one
The end of the lance allows it to be moved back into the interior of the lance; Measure (X). This offset allows the nozzle bottom against particles thrown up, in particular
to protect "sucked in" particles.

- In addition to the suction of external gases, with
To reduce the particles contained therein against the nozzle base, one or more openings can be provided in addition to the normal blower nozzles, from which gas exits, preferably with reduced kinetic energy. This gas is first "sucked in" and forms an insulating layer in front of the bottom of the lance.

A single annular opening (4) is preferably provided on the outer edge of the nozzle base.

- The nozzle base is made of all refractory metallic or ceramic materials or one
Combination of these materials.

The material is not selected from the point of view of good heat transfer, but exclusively from the point of view of mechanical strength
and the temperature resistance. This taking into account the fact that the nozzle base is cooled by the escaping gas.

A partial or complete destruction of the nozzle bottom only changes the blowing characteristics, can
however, never cause a leakage incident.

5 pages description

1 page of claims

2 drawings

0 3 00U / 0722

GOPY

Blank page

COPY

Claims (6)

Claims 1) Unit with one or more blowing nozzles, for blowing gases, especially oxygen, with or without Solids content, on or in a bath of molten metal, and characterized in that the nozzle bottom is separate and independent of the end of the lance. 2) Unit according to claim 1, characterized in that the nozzle base is installed with a recess opposite the end of the lance. 3) Unit according to claim 1 or 2, characterized by the presence, in addition to the normal blower nozzles, from one or more openings from which gas can flow out at a normally lower speed like from the blow nozzles. 4) Unit according to claim 1 or 2 or 3, characterized in that the nozzle bottom made of heat-resistant metallic materials is made. 5) Unit according to claim 1 or 2 or 3, characterized in that the nozzle bottom made of heat-resistant ceramic materials is made. 6) Unit according to claim 1 or 2 or 3, characterized in that the nozzle base is made of heat-resistant metallic and ceramic materials is made. 030014/0722 ORIGINAL INSPECTED