Strip deflector and roll assembly

Abstract

A strip deflector has a base body formed with a tip, a compressed-air chamber, and a nozzle for emitting compressed air. A compressed-air source in flow communication with the compressed-air chamber feeds compressed air to the compressed-air chamber and the nozzle. This nozzle has a first nozzle subpassage in flow communication with the compressed-air chamber and a second nozzle subpassage downstream of the first nozzle subpassage in a flow direction. The first nozzle subpassage is formed by a flank closer to the tip of the base body and an opposite flank remote from the tip of the base body, and, at a transition from the first nozzle subpassage to the second nozzle subpassage, the flank closer to the tip of the base body is bent away toward the tip of the base body so as to form a first separation edge.

Claims

1. A strip deflector for contactless deflection of a rolling medium from the surface of a strip comprising: a base body forming formed with a tip, with at least one compressed-air chamber, and with at least one nozzle for emitting compressed air; and a compressed-air source in flow communication with the compressed-air chamber for feeding compressed air to the compressed-air chamber and the nozzle, wherein the nozzle has a first nozzle subpassage in flow communication with the compressed-air chamber and a second nozzle subpassage downstream of the first nozzle subpassage in a flow direction, the first nozzle subpassage is formed by a flank closer to the tip of the base body and an opposite flank remote from the tip of the base body, at a transition from the first nozzle subpassage to the second nozzle subpassage, the flank closer to the tip of the base body is bent away toward the tip of the base body so as to form a first separation edge, the second nozzle subpassage is bounded by a continuation of the flank remote from the tip of the base body and beyond the first separation edge in the flow direction; and the flank remote from the tip of the base body is bent away from the tip of the strip deflector so as to form a second separation edge at the end of the second nozzle subpassage.

2. The strip deflector according to claim 1, wherein a section that bounds the second nozzle subpassage of the flank remote from the tip of the base body defines a unitary or common plane or is formed to be convexly curved both in the region of the first nozzle subpassage and in the region of the second nozzle subpassage.

3. The strip deflector according to claim 1, wherein a drop-shaped, convexly curved flow guide profile is formed between the offset first separation edge and the tip of the base body.

4. The strip deflector according to claim 3, wherein an angle is between the flow direction in the first nozzle subpassage and a connecting line that is between the tip of the base body and the first separation edge; the smaller the angle, the smaller the curvature of the flow guide profile.

5. The strip deflector according to claim 1, wherein the compressed-air source is a compressor for generating compressed air at 3 bars or a fan for generating compressed air at 1.5 bars, and air flow in the nozzle in both cases attains only a subsonic velocity.

6. The strip deflector according to claim 1, wherein the strip deflector has in a width direction a plurality of pressure chambers that are each connected with the compressed-air source by a respective feed line each in turn individually closable by a respective shut-off valve.

7. The strip deflector according to claim 1, wherein the nozzle is formed as a slot nozzle over an entire width of the strip deflector.

8. The strip deflector according to claim 1, wherein the nozzle is formed over an entire width of the strip deflector from a plurality of individual nozzles.

9. The strip deflector according to claim 1, wherein the tip of the base body of the strip deflector is detachably connected as a separate component with the base body.

10. The strip deflector according to claim 1, wherein the tip is made of metal or plastic.

11. A roll assembly comprising at least one roll and at least one strip deflector according to claim 1, wherein the strip deflector in the region of the tip of the base body is spaced from the roll by a gap with a gap width d of d=1 to 9 mm.

12. The roll assembly according to claim 11, wherein two or more of the strip deflectors are angularly spaced about the roll.

13. The roll assembly according to claim 11, wherein the flank remote from the tip of the base body, of the second nozzle subpassage is convexly curved, the convex curvature for a given placement of the strip deflector against the roll being formed to be merely so small that a tangent to the flank of the second nozzle subpassage at the second separation edge still extends through the roll body or is at least tangential thereto.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The description is accompanied by three figures, in which:

(2) FIG. 1 is a cross-section through a first embodiment of the roll assembly according to the invention with the strip deflector according to the invention;

(3) FIG. 2 shows a second embodiment of the roll assembly according to the invention in accordance; and

(4) FIG. 3 shows a third embodiment of the roll assembly according to the invention in a perspective view.

SPECIFIC DESCRIPTION OF THE INVENTION

(5) The embodiments of the invention are described in detail in the following with reference to FIGS. 1 to 3. The same elements are denoted in all figures by the same reference numerals.

(6) The roll assembly according to the invention can be seen in FIG. 1, according to which a strip deflector 100 according to the invention is juxtaposed with the outer surface of a roll 300. The metal strip 200 to be rolled or being rolled can be seen in the lower region of FIG. 1, extending tangentially with respect to the roll outer surface. The strip deflector 100 is positioned by its base body 110 with a gap between itself and the roll 300. The gap width d is, for example, 1 to 9 mm.

(7) The strip deflector 100 consists substantially of the base body 110 formed with at least one compressed-air chamber 114 and a nozzle 116 communicating with the compressed-air chamber for discharge of compressed air against the outer surface of the roll 300. The compressed air is provided by a compressed-air source 118 (see FIG. 3) communicating with the compressed-air chamber 114. The flow-conducting connection between the compressed-air chamber 114 and the nozzle 116 can be constructed in the form of, for example, a connecting passage 115.

(8) The nozzle 116 consists of a first nozzle subpassage 116-I communicating with the compressed-air chamber 114 and a second nozzle subpassage 116-II downstream of the first nozzle subpassage in a flow direction R of the compressed air. The first nozzle subpassage 116-I can either be formed directly as a continuation of the compressed-air chamber 114 or be connected in terms of flow with the compressed-air chamber 114 by an intermediate passage 119.

(9) In concrete terms the first nozzle subpassage 116-I consists of two flanks 116-I-1 and 116-I-2 preferably extending spacedly parallel to each other, the first flank 116-I-1 being designated as that closer to a tip 112 of the base body 110 and the other, opposite flank 116-I-2 being remote from the tip 112 of the base body.

(10) In the transition from the first nozzle subpassage to the second nozzle subpassage the flank 116-I-1 closer to the tip 112 of the base body 110 is bent away toward the tip 112 of the base body so as to form a first separation edge 117.

(11) A drop-shaped convexly curved flow guide profile 120 is preferably formed between the stepped first separation edge 117 and the tip 112 of the base body 110. The flow guide profile 120 merges, preferably by a concave curvature preferably formed to be curved smoothly, i.e. without formation of kinks, into the tip 112 of the base body 110. The curvature of the flow guide profile 120 can be smaller, proportional to an angle is between the flow direction R in the first nozzle subpassage 116-I and a connecting straight line g between the tip 112 of the base body and the first separation edge 118 (see FIG. 2).

(12) In the case of a suitable construction, as an alternative to the angle , the angle between the direction of the first nozzle subpassage 116-I and the intermediate passage can possibly also serve as a stop point for the height of the curvature of the flow guide profile 120. In the case of the embodiment shown in FIG. 1, a right angle is formed between the first nozzle subpassage 116-I and the intermediate passage 115 [119]. By contrast, in the embodiment shown in FIG. 2 an acute angle is formed between the first nozzle subpassage 116-I and the intermediate passage [115]. Accordingly, the curvature of the flow guide contour 120 can be less pronounced in the case of the embodiment shown in FIG. 2 than in the case of the embodiment shown in FIG. 1.

(13) The second nozzle subpassage 116-II forms the continuation of the first nozzle subpassage and is defined or bounded substantially by the continuation of the side 116-I-2 remote from the tip 112 of the base body, in flow direction R beyond the height of the separation edge 117. The flank 116-I-2 remote from the tip of the base body is bent away from the tip 112 of the strip deflector so as to form a second separation edge 119 at the end of the second nozzle subpassage 116-II.

(14) It is important that not only the first separation edge 117, but also the second separation edge 119 be sharp with a smallest possible radius of curvature so as to ensure that the air flow at the two separation edges does not follow the bent-over profile of the base body in these regions due to Coanda effect, but instead flows in its original flow direction further along on the roll outer surface or at least tangentially to the surface of the roll outer surface.

(15) The flanks remote from the tip 112 of the base body 110 can each be formed as a single common plane in the region of the first nozzle subpassage 116-I and the second nozzle subpassage 116-II. Alternatively, the flanks in both nozzle subpassages or also only in the second nozzle subpassage up to the second separation edge can be formed to be bent slightly convexly away from the tip 112. However, the convex curvature should then at most be so strongly formed, particularly in the region of the second nozzle subpassage 116-II up to the second separation edge 110, that the air flowfor a given placement of the strip deflector 100 against the outer surface of the roll 300still impinges on the surface of the roll 300 or at least flows tangentially along the outer surface thereof when exiting from the nozzle. In other words, the convex curvature in this region should only be so strongly formedfor a given position of the strip deflector relative to the rollthat a tangent to the flank 116-II of the second nozzle subpassage at the second separation edge still hits on the roll outer surface or is at least tangential thereto.

(16) The tip 112 of the strip deflector 100 is preferably constructed to be detachably connectable as a separate component with the base body. This is advantageous, because in practice the tip is subject to a high level of wear. It can be made of metal or plastic.

(17) FIG. 3 shows how the nozzle can be formed to be, for example, slot-shaped. Alternatively, however, it can also be formed with a plurality of individual nozzles or individual bores that communicate with the compressed-air chamber 114.

(18) FIG. 3 also shows how the compressed-air chamber 114 can be constructed in the form of a plurality of N individual compressed-air chambers 114-n, where 1nN and each of the individual compressed-air chambers is provided for supply of a specific section of the nozzle 116 in width direction with compressed air. For this purpose the individual compressed-air chambers 114-n are preferably each connected with the compressed-air source 118 by an individual feed line. Each of the feed lines can be preferably individually blocked by an individual shut-off valve 115-n, where 1nN. The advantage of this embodiment in terms of the compressed air supply of the nozzle 116 being variably adaptable in width direction to the width of the respective strip 200 to be rolled or being rolled was already described above.

(19) In constructional terms the base body 110 of the strip deflector according to the invention can be formed from a lower shaped part 110-1 and an upper shaped part 110-2.