EP0662359B1 - Device for sealing without contact a gap on the outlet of a rolling stand - Google Patents

Description

The quality of a strip is in the outlet of rolling mills crucial through dryness and cleanliness of the Belt surface affected. In practice, e.g. Very much at the moment different types of blow-offs, partitions and / or Extractors and their combinations used. However no satisfactory solution has been found so far. This is that in the case of blow-offs just behind the last one Work roll creates an air jam, causing moisture in Form of drops and / or other particles on the tape fall behind and thus reduce the tape quality. To the itself difficulties resulting from this have been overcome already combinations of blows and suction in the Area of a rolling mill outlet used. With that, however other disadvantages connected because z. B. Such combinations due to the large to be promoted with pressure or negative pressure Air masses very complex and expensive and therefore uneconomical are. Designed for large amounts of air, they are also used for other facilities urgently needed space. If to To remedy this difficulty blow off or their Combination with suction further towards the outlet positioned, they lose with increasing distance considerably effective and the moisture stays on the belt be liable.

1. Der gesamte Auslaufbereich des Bandes muß gegenüber Walzöl, das sich hinter dem Walzspalt im Auslauf befindet, oberhalb und unterhalb des Bandes abgeschottet sein;

2. Spalten zwischen rotierenden, feststehenden oder linear bewegten Teilen müssen berührungsfrei mit einem definierten Luftstrom abgedichtet bzw. abgeschottet werden. Es ist eine anerkannte Forderung, daß an den Walzen keine Dichtungen schleifend anliegen dürfen;

3. nasse Flächen, insbesondere in Reversiergerüsten, müssen mit Hilfe einer großen trockenen Luftmenge schnell getrocknet werden;

4. mitgerissene Flüssigkeit seitlich der Bandkanten muß unmittelbar hinter dem Walzspalt abgelenkt werden, weil erfahrungsgemäß Flüssigkeitstropfen (Emulsion/Walzöl) nach Erreichen der Bandgeschwindigkeit nicht mehr mit Luft weggeblasen werden können.

Proceeding from this, the object of the invention is to design a device for the contact-free sealing of a gap in the outlet of a roll stand in such a way that a dry and clean strip is obtained while avoiding the aforementioned difficulties and technical limits, the following conditions being met:

1. The entire outlet area of the strip must be sealed off from the rolling oil located behind the roll gap in the outlet, above and below the strip;

2. Gaps between rotating, stationary or linearly moving parts must be sealed or sealed off without contact with a defined air flow. It is a recognized requirement that seals should not be rubbing against the rollers;

3. Wet surfaces, especially in reversing stands, must be dried quickly using a large amount of dry air;

4. entrained liquid to the side of the strip edges must be deflected immediately behind the roll gap, because experience has shown that liquid drops (emulsion / rolling oil) can no longer be blown away with air after the strip speed has been reached.

The problem is solved with the invention by the im Features specified claim 1, being the first in surprisingly effective and uncomplicated way a long one Gap between partition and work roll with one an energy-intensive flow emerging from a slit nozzle is sealed. The function is based on the effect of "Prandtl-Meyer corner flow". By the invention Formation of the end partition element with its cutting-like tapered end part and its arrangement relative to the work roll is achieved that between this and the roller has an injector-like flow cross section forms. In this arises under the effect of one-sided expanding, high-energy jet a negative pressure. This causes large amounts of air to pass through the gap between Foreclosure element and roller sucked in the direction Flow wet area. As a result, the air congestion becomes significant reduced and a defined flow forms between Foreclosure and rolling stock, in whose area the wet air with Drops and other particles is suctioned off. The on this Way integrated into the foreclosure in a confined space Combination of blow-off and suction provides effective support the fume extraction as well as the belt edge blowing and enables quick drying of the dripping wet surfaces in the Exit of a rolling or reservation rolling mill. The device can be used above and below the belt run. The Arrangement can occur at many points on a rolling mill conveyor belt or rotating rollers are used there, where it is necessary to separate different air spaces.

Further refinements of the invention are in accordance with Features of the subclaims are provided. The invention is in schematic drawings in a preferred embodiment shown, with further advantageous from the drawings Details of the invention can be found.

Fig. 1

in Seitenansicht ein endseitiges Abschottungselement der Vorrichtung mit Ausbildung einer Spaltdüse, teilweise im Schnitt,

Fig. 2

eine vollständige Vorrichtung zum berührungsfreien Abdichten eines Spaltes zwischen Abschottung und Arbeitswalze, in Seitenansicht.

Show it:

Fig. 1

in side view an end-side partition element of the device with the formation of a gap nozzle, partly in section,

Fig. 2

a complete device for contactless sealing of a gap between the partition and work roll, in side view.

Figure 1 shows an end sealing element (2) in Figure 2 completely shown device. The Partitioning element (2) or its end part (3) is under Formation of a contact-free gap approximately tangential to the surface of the work roll (20) and in a relatively small amount Distance to this as well as to the surface (31) of the rolling stock (30) arranged. It has at least one on a compressed air source (10) connected supply duct (11) for compressed air, which in a little in the direction of the roller axis Gap nozzle extending at a distance along the roll surface (12) flows into. This emerges with pressures between 0.5 and 4 bar of compressed air supplied to form a energy-rich and covering the width of the roller (20) Air jet. This forms between the Blow-out direction (y-y) of the gap nozzle (12) and one of the Nozzle mouth (13) to the axis of rotation of the work roll (20) normal (z-z) an angle (alpha), which in Direction of rotation of the roller (20) between 0 and 45 degrees, is preferably 30 degrees. After leaving the nozzle gap (12) the air jet expands. Through the one-sided burst air jet deflected at an angle (alpha) arises in the ever expanding injector-like Flow channel (25) negative pressure, which with the help of its Suction up to 20 times the volume of the jet Air through the gap between the partition element (2) and Sucks roller (20). In this way, the gap between partitioning element (2) and work roll (20) a defined air flow in the direction of the wet area effective seal off without creating an air jam.

A favorable form of flow of the driving jet for training a negative pressure in the flow channel (25) is shown in FIG. 1 achieved in that the gap nozzle between a gradation (14) of the end part (3) and a the width of the nozzle gap (17) determining adjustable guide member (15) is. The gap of the nozzle (12) is between 0.1 mm in widths and 4 mm adjustable, the preferred width is 0.2 mm. This will continue to expand the jet favors that the guide member (15), seen in cross section, starting from the direction of the nozzle gap (17) in a backward curved flow guide surface (16) merges. Thereby there is a bumpless, constant spreading of the Jet jet for a powerful suction.

The gap of the gap nozzle can be located in the area of the roller (20) (12) can be relatively larger, which means larger amounts of air here be sucked off.

Furthermore, the suction is supported by the fact that Partitioning element (2) in the area between its free end and the gap nozzle (12) in the end part (3) arranged suction channels (4), wherein each intake duct (4) obliquely upwards in the acute angle (beta) directed against the roller surface is.

In Fig. 1 it is also shown that the partitioning element (2) at least one at a distance behind the gap nozzle (12) Has water drainage channel (26). This will cause airflow entrained liquid, which is in the form of drops on the Partition element (2) precipitates, derived to the side and thus prevents liquid from running back.

Figure 2 shows the arrangement according to the invention in the installed state inside the bulkhead (1). This arrangement results in a very effective combination of blow-off of the roller (20) and Suction of the surface (31) of the rolling stock (30) comparatively small space. At the bottom of the Bulkhead (1) the partitioning element (2) is arranged, the gap nozzle between this and its end part (3) (12) is formed. The end part (3) is touchless a small gap-like distance approximately tangential the surface of the roller (20). The gap nozzle (12) is with connected to the supply duct (11) for compressed air. Above the Partitioning element (2) is one in the bulkhead (1) Trough (40) arranged with side drain pipes (41). The trough (40) serves to collect Liquid droplets resulting from the wet flow of the Depress flow channel (25 Fig. 1). Furthermore shows Fig. 2 shows the arrangement of blowing nozzles (45) on a nozzle head (44). These have the task of the edges of the rolled strip (30) of entrained liquid such as water and / or rolling oil to blow off. The air space (47) between the rollers (20, 21) and the bulkhead (1) is connected to an extractor fan (48) connected.

The device is straightforward due to the fluidic design very effective and fulfilled in optimally the task at the beginning.

Claims (8)

1. Device for contactless sealing of a gap between a partition (1) and a working roll (20) in the outlet of a roll stand, characterised by the features

   (a) the partition (1) has at the end a partitioning element (2), which is arranged approximately tangentially to the surface of the working roll (20) and at relatively small spacing relative thereto as well as to the surface (31) of the roll stock (30);

   b) the partitioning element (2) has at least one feed channel (11), which is connected to a compressed source (10), for compressed air and which opens into a gap nozzle (12) extending in direction of the roll axis at small spacing along the roll surface;

   c) an angle (alpha), which in rotational direction of the roll (20) amounts to between 0 and 45° and preferably to 30°, results between the blast direction (y - y) of the gap nozzle (12) and a normal (z - z) extending from the nozzle opening (13) to the axis of rotation of the working roll (20);

   d) the partitioning element (2) has at its forward end an end part (3), which is arranged approximately tangentially and at small spacing to the roll surface and tapers in edge-like manner and which is constructed and arranged in such a manner that between this and the roll surface a flow channel (25) is formed in the manner of an injector, which channel constantly enlarges in cross-section and extends axially parallel to the working roll (20) at least in the width of the roll stock (30).
2. Device according to claim 1, characterised thereby that the gap nozzle (12) is formed between a step (14) of the end part (3) of the partitioning element (2) and a guide element (15) adjustably determining the width of the nozzle gap (17).
3. Device according to claim 1 or 2, characterised thereby that the nozzle gap is settable in width between 0.1 millimetres and 4 millimetres and amounts to the preferred width of 0.2 millimetres, wherein the gap is relatively large in the lynette region of the working roll (20).
4. Device according to one of claims 1 to 3, characterised thereby that the guide element (15) as seen in cross-section and going out from the direction of the nozzle gap (17) goes over into a rearwardly curved flow guide surface (16).
5. Device according to one of claims 1 to 4, characterised thereby that the end part (3) in the region between its free end and the gap nozzle (12) has at least one suction channel (4) which penetrates this and which is oriented obliquely upwards at an acute angle (beta) towards the roll surface.
6. Device according to one of claims 1 to 5, characterised thereby that the partitioning element (2) has at least one water outlet groove (26) at a spacing behind the gap nozzle (12).
7. Device according to one of claims 1 to 6, characterised thereby that the partitioning element (2) is arranged to project through a lower passage in a part of the partition wall (1) or of the pivot frame by a slide at a guide and is linearly movable with the aid of a drive device and settable at a defined spacing relative to the roll surface.
8. Device according to one of claims 1 to 7, characterised thereby that the air space (4) is connected to a dust extractor (48) between the rolls (20, 21) and the partition wall (1).

Images