LU83248A1 - SLINGER DRUM FOR METALLURGICAL SLAG - Google Patents

Description

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The invention relates to a centrifugal drum for metallurgical slag, in particular for liquid blast furnace slag for producing slag sand or pumice.

A known possibility of processing the liquid slag consists in mechanical blow and spin treatment. A system of this type is described in more detail in Belgian Patent No. 847,483. In this . The patent proposes a method and a production plant for foamed slag, in which a mechanical treatment of a metallurgical slag stream is carried out with the aid of a rotating drum, the liquid slag being first subjected to swelling by the supply of water. The slag that then falls down onto the drum is torn apart by transverse bars attached to the drum and flung away in an arc.

It was found some time ago that the plant proposed in this Belgian patent no. 847,483 can be used not only for the production of swollen slag, the so-called metallurgical pumice, but also for the production of slag sand, as is produced in conventional granulating plants. This process is proposed in Luxembourg Patent No. 77,160 dated April 19, 1977. The production of slag sand carried out in this way is made possible by acting on various working parameters, such as the speed of rotation of the drum and the amount of water added. The proportion of slag sand increases at the expense of pumice if the speed of the drum and the speed in the swelling phase

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These systems with a rotating drum have the great advantage of up to 90% water savings compared to those with granulation pits. As a result, the plants for the separation of water and slag sand or pumice and also the drying plants can be kept less complex and costly.

A major problem in systems with centrifugal drums, however, are the downtimes, particularly in the area of the blow bars with which the drum casing is provided. Although the drum itself is water-cooled from the inside and the strips may also be provided with cavities for water circulation, this cooling has so far not been able to be carried out specifically and intensely enough to prevent destruction, in particular of the blow molding weld seams, within the shortest possible time. For example, the lifespan of the well-known processing drums of only approx. 10,000 tons of slag.

In order to avoid air pockets and circulation congestion in the cooling channels, the drum jacket also had to be provided with openings through which the cooling water can escape in order to be thrown away * with the slag. The disadvantage here, however, is that this addition of water, which is indispensable for cooling, also enters the slag treatment process and, as already noted above, is not - because of its influence on the quality of the product obtained - absolutely desirable, at least not in such quantities as it is I are necessary for cooling the drum.

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To avoid these disadvantages in the current state of the art, it is the object of the invention to propose a centrifugal drum for metallurgical slag, in which the drum casing and the blow bars are cooled in the most intensive manner from the inside and without water escaping from the drum casing, and their service life is accordingly extended.

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This object is achieved by a centrifugal • drum of the type mentioned at the outset, characterized in that the outer jacket consists of cooling tubes running close together in the axial direction, which on one side through a distribution chamber with a cooling water inlet and on the opposite side via a Connect the collector chamber to a water outlet.

Distributed over the drum circumference, a number of blow bars can furthermore advantageously be provided, which are arranged between the pipes and welded to these and an inner drum jacket, and which are also provided with axial cooling channels for intensive water circulation.

v An embodiment of the invention is in the

Drawings in which the same parts are provided with the same reference numbers are shown and will be described in more detail below. Show it:

Figure 1, a longitudinal section through a centrifugal drum of the proposed type;

Figure 2 shows a cross section through the drum of Figure 1; / V ^ Figure 3, a side view in the direction X a

Water supply flange on the drum according to FIG. 1.

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The drum, generally designated 4, is carried by two lateral outer flanges 14, 16, which are firmly connected to two hubs 6, 8. These two hubs are provided with * internal, preferably axial bores 10, 12 for the supply or removal of cooling water.

The outer flanges 14, 16 are welded to an inner flange 15 and 19 via a cylindrical intermediate piece 13 and 17, respectively, and form with them a distributor chamber 28 and a collector chamber 30 for the cooling water.

The drum shell consists of a number of cooling tubes 20, 22 welded to one another in the longitudinal direction, which connect the distributor chamber 28 to the collector chamber. To reinforce the drum, the drum jacket is preferably carried by an inner, fixed jacket 18 which is welded to the inner flanges 15, 19 on both sides.

A number of radial blow bars 26 are attached to the drum jacket 24 to intensify the impact and centrifugal effect. These blow bars 26 are also cooled and, as shown in FIG. 2, can consist of approximately rectangular bars with cooling channels 32.

But you can also as a further development of the invention from individual, e.g. there are three cooling tubes lying one above the other in the radial direction and welded to one another. The cooling channels 32 or the welded-together cooling tubes of the blow bars 26 are also connected to the two chambers 28 and 30.

The bores 120, 122 (see FIG. 3) for receiving the cooling tubes 20, 22 in the flanges 15, 19 are // preferably radially offset. This prevents

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- 6 - the bores 120, 122 form an annular interruption in the flanges. The associated cooling tubes 22 are bent radially on both sides accordingly (see FIG. 1).

The flanges 15, 19 also have cutouts 34 (see FIG. 3) for receiving the blow bars 26.

FIG. 2 shows how the cooling tubes 20, 22 are welded to one another and to the inner jacket 18, and the strips 26 are welded to this jacket 18 and the cooling tubes 20, 22. It can be seen that the most vulnerable weld seams, that is those between the inner jacket 18 and the strips 26, i.e. the seams 36 are in an intensely cooled area.

In order to prevent that on the inlet side of the cooling water, due to the inertia, a standing or slower rotating "water flange" occurs in the chamber 28, which would hinder the flow into the cooling pipes 20, 22, entraining elements are in the chamber 28 are provided which immediately force the water on entering the chamber 28 through the bore 10 at the same rotational speed as that of the drum '

Way, as indicated by dashed lines in Figure 3, consist of radial blades 40 which are welded to the flanges 14 and 15 on both sides. Similar measures can be taken in the collector chamber.

Instead of draining the water through the hub 8, it is also possible to connect the chamber 30 to the hub 6 via an axial line. The latter would then contain the inflow line and a ^^^ drain line arranged concentrically to it.

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The chambers 28, 30 are provided with ventilation plugs 38, 40, in order to remove air pockets, in particular before the drum is started up for the first time, which could impair the cooling water circulation and possibly serve as emptying plugs.

The proposed centrifugal drum design permits very intensive cooling of the parts at risk, since the entire cooling water throughput takes place specifically at the periphery of the drum. There are no more air pockets in the parts to be cooled and the cooling water is distributed evenly over the drum circumference.

The cooling device according to the invention also has a positive influence on the treatment process itself in the sense that the cooling water is no longer thrown out of the drum shell and thus adversely affects the treatment process of the slag. The slag can, as desired, be cooled by air.

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Claims (9)

1. centrifugal drum for metallurgical slag, in particular liquid blast furnace slag, for the production of slag sand or metallurgical pumice, characterized in that the outer jacket (24) consists of cooling tubes (20, 22) which run in the axial direction and lie close together, which is on one side through a distribution chamber (28) with a cooling water inlet and on the opposite side via a collector chamber (30) with a water outlet in connection. 2. centrifugal drum according to claim 1, characterized in that the outer casing (24) is supported by an inner casing (18). 3. centrifugal drum according to claim 1, characterized in that the cooling tubes (20, 22) are welded to one another and to the inner jacket (18) in the longitudinal direction. 4. centrifugal drum according to one of claims 1 to 2, characterized by a number, distributed over the drum circumference, cooled blow bars (26) which are connected to the chambers (28) (30). 5. centrifugal drum according to claim 1, characterized in that the distribution chamber (28) is equipped with driver elements. 6. centrifugal drum according to claim 1 or 5, characterized in that the collector chamber (30) I is also equipped with driver elements. h »- 9 - 7. centrifugal drum according to claims 1 to 6, characterized by radially offset pipe connections (120, 122) on the chambers (28, 30) for straight cooling tubes (20) and cranked cooling tubes (22). 8. centrifugal drum according to claims 1 to 7, »characterized by recesses (34) on the chambers * (28, 30) for receiving and fastening the blow bars (26) and for hydraulically connecting their cooling lines» with the interior of the chambers (28, 30). 9. centrifugal drum according to claims 1 to 8, characterized by ventilation plugs (38, 40) on the circumference of the chambers (28, 30). y%