EP3140056B1 - Strip deflector and roll assembly - Google Patents

Description

The present invention relates to a belt deflector. Belt deflectors are shielding devices in rolling stands for rolling typically metal strip. During rolling, the rolls are often loaded with a rolling medium, such as a coolant and / or lubricant; the Bandabweiser then serve in addition to the contactless removal of the coolant or lubricant from the surface of the metal strip. Moreover, the invention relates to a roller assembly having at least one roller and at least one belt deflector according to the invention.

The remainder of the prior art is based on the European patent applications EP 0 765 696 . EP 0 513 632 and EP 1 474 253 and the US writings US 5,490,300 and US 6,260,287 directed.

The belt deflector according to the invention represents a further development of the belt deflector, as described in European Patent EP 0 662 359 is disclosed. The from the European patent EP 0 662 359 B1 Known tape deflector consists essentially of a main body with a tip. In the main body at least one compressed air chamber and a nozzle for the discharge of compressed air from the compressed air chamber is formed. The compressed air chamber is flow-connected to a source of compressed air, which provides compressed air for the compressed air chamber and the nozzle. The nozzle consists of a with the compressed air chamber flow-connected first nozzle channel portion and a second nozzle channel portion, which is connected downstream of the first nozzle channel portion in the flow direction. The first nozzle channel portion consists of two substantially parallel side walls, wherein the one side wall is referred to as the tip of the base body, while the other side wall is referred to as facing away from the top of the base body. In the transition from the first to the second nozzle channel section which faces the tip of the base body Side wall bent to form a first tear-off edge to the top of the body out. The second nozzle channel section is essentially formed by an extension or an extension section of the side wall facing away from the tip of the base body in the flow direction beyond the first tear-off edge.

The from the EP 0 662 359 B1 known belt deflector has a nozzle which is slotted throughout the width of the rolled or rolled strip. By means of the nozzle or the compressed air flow emerging from the nozzle, a gap between the belt deflector and a roller, against which the belt deflector is made, is sealed against existing coolants and / or lubricants using the mode of action of the Prandtl-Meyer corner flow.

In the Prandtl-Meyer corner flow is a phenomenon in the field of gas dynamics, namely the fluid deflection in the supersonic range. This effect of flow diversion and flow broadening results in an effective seal of a gap between the roll barrel of a work roll and a belt deflector attached to the roll barrel. Specifically, the effect effectively prevents the penetration of coolant or lubricant from an area above the belt deflector into an area between the belt deflector and the surface of the rolled or rolled strip. By a high suction in the gap between the roll barrel and the employee Bandabweiser even more ambient air from the area between the belt deflector and the belt surface through the gap between the roller and the belt deflector in the area above the belt deflector dissipated or sucked. This has the advantage that said rolling media can no longer disturbing deposit on the tape. The guidance of the air flow is supported by the so-called Coanda effect, in which the tendency of a jet of fluid becomes apparent, to walk along a convex surface instead of settling or peeling off.

In practice, it has been shown that the structural design of the from EP 0 662 359 known Bandabweisers is not completely satisfactory in terms of various functions. In particular, the fact that the fluid, here compressed air, must be accelerated to supersonic speed in order to achieve the said high suction with the aid of the Prandtl-Meyer corner flow, shows disadvantages. On the one hand is to call the high noise associated with the supersonic speed of compressed air as a disadvantage and on the other is also associated with the extremely high and costly compressed air consumption. A further disadvantage is that due to the strongly rounded exit region of the known nozzle, the exiting air flow is led away in substantial parts from the roll surface due to the Coanda effect, as a result of which the sealing effect becomes only sub-optimal. This sub-optimal sealing effect is essentially due to the fact that vortex form between the deflected air flow and the roll surface, which lead the repellent medium in the immediate vicinity of the roll bale partly in the direction of the belt deflector, instead of conveying it away from him.

The invention has the object of developing a known belt deflector for rejecting rolling medium of metal strip in a rolling mill and a known roller assembly with such a belt deflector to the effect that the sealing effect of the belt deflector against a roll in a rolling mill is improved.

This object is solved by the subject matter of patent claim 1. This is characterized in that the side wall facing away from the tip of the base body is bent away from the tip of the belt deflector to form a second tear-off edge at the end of the second nozzle channel section.

The term "strip" in the sense of the present invention means a metal strip to be rolled or rolled.

The term "tear-off edge" in the sense of the present invention means an edge whose cross-sectional contour - in mathematical ideal theory terms - is continuous but not differentiable. The first and the second tear-off edge, due to their in each case sharp-edged cross-sectional contour, that the air flow in the nozzle after passing the tear-off can not follow the contour of the nozzle, that is not strongly deflected, but in the original direction, as before the first Düsenkanalabschnitt specified, continues to flow.

The term "rolling medium" means cooling medium and / or lubricating medium, which is applied for rolling the strip on the rollers or the belt.

The claimed design of the second tear-off edge offers the advantage that the air flow at the end of the second nozzle channel section actually flows substantially further in its current flow direction towards the roll barrel or at least tangentially along the roll barrel and not - as described in the prior art - due the Coanda effect of the curvature follows at the end of the side wall of the second nozzle channel portion and is directed away from the roll barrel. The air flow realized by the claimed second tear-off edge closely along the roll bale advantageously prevents swirling of the air flow in the vicinity above the strip deflector, whereby the sealing effect of the strip deflector compared to an associated roll is markedly improved, because no rolling medium is more by vortex formation in the direction of the belt deflector or is guided in the direction of the nozzle.

The claimed construction of the second nozzle channel portion with the second tear-off edge is geometrically extremely simple and thus inexpensive to manufacture. There are no elaborate curves and convex surfaces are made. Only the defined second tear-off edge must be precisely defined and formed.

According to a first embodiment, the side wall facing away from the tip of the main body forms a uniform plane both in the region of the first nozzle channel section and in the region of the second nozzle channel section.

If a drop-shaped convex-curved Strömungsleitkontur formed between the stepped first tear-off edge and the top of the body, this has the advantage that the gap between the band deflector in the region between the tip of the body and the nozzle and the opposite roll barrel is clearly defined and otherwise existing free space, which would be present without the claimed Strömungsleitkontur filled out. The filling of the void space prevents the formation of undesirable vortices with undesired retrograde air flow in this area, and thus the suction in the nip between the belt deflector and the roll barrel, whereby rolling medium in the area between the belt deflector and the tape is sucked, improved. The air in the nip is passed without turbulence along the surface of the roll bale.

The curvature of the Strömungsleitkontur can be advantageously formed smaller, the smaller, ie the sharper the angle a between the flow direction R in the first nozzle channel portion and a connecting line between the tip of the body and the first tear-off edge.

As a compressed air source either a compressor for generating compressed air with, for example, <3 bar or a fan for generating compressed air with, for example, <1.5 bar can be used. It is important that the air flow in the nozzle in any case in the present invention may only reach subsonic speed; Thus, the physical action principle of the Prandtl-Meyer effect, which applies only to supersonic flows, no longer applies in the present invention. The use of a fan for compressed air generation has the advantage that the compressed air provided in this way is significantly cheaper than the typically existing factory compressed air. Due to the limitation of the air flow to the subsonic speed range is advantageously achieved that the noise level and the consumption of compressed air per unit time, compared to the use of compressed air in the supersonic speed range, are significantly reduced.

According to a further embodiment, the band deflector in the width direction may comprise a plurality of pressure chambers, which are each connected via a separate supply line to the compressed air source. Preferably, each of the supply lines via a private shut-off valve can be shut off individually. The provision of the plurality of pressure chambers in conjunction with the individual shut-off valves has the advantage that the width of the belt deflector used in practice on the respectively used roll width and the width of the belt is adjustable, in particular the edge regions of the belt deflector by means of the shut-off valves optionally be shut off by a compressed air supply. In this way, advantageously, the operating costs, especially for the expensive compressed air consumption, can be reduced. Furthermore, the described embodiment offers the advantage of an increased variance of the permissible frame geometries: The band thickness spectrum and the roll grinding area can be made variable without impairing the functionality. The nozzle of the scraper according to the invention extends over the entire width the band deflector and may be formed either as a slot or a plurality of individual holes.

The region of the tip of the main body is particularly wear-intensive, since it repeatedly comes in Bandeinfädeln or -ausfädeln and tape tears to high loads in this area. If the tip of the main body of the band deflector is formed as a separate component detachably connected to the main body, this offers the advantage that the tip can be easily replaced as a wearing part. This is typically much cheaper than replacing the entire belt deflector. The tip of the base body may be made of metal or plastic, for example.

The above object is further achieved by a roller assembly having at least one roller and at least one - except for a gap - against the bale of the roller employed Bandabweiser according to one of the preceding claims. In this case, the band deflector is employed at least in the region of the tip of the main body via a gap with a gap width d between 1 to 9 mm, preferably 5 mm, spaced from the roller. At the first Abißkante ends of the short first nozzle channel portion and the air then flows in the downstream second nozzle channel portion beyond the upper second tear edge. Due to the inertia of the flow, the flow strikes from there to the opposite roll barrel and thus seals the gap between the roll barrel and the belt deflector without contact. The mentioned gap width of up to about 9 mm advantageously allows much more media-laden air to be removed from the air region between the strip surface and the strip deflector than was the case with the nozzle of the prior art operated with supersonic compressed air. In the known nozzle, the ratio of supplied compressed air to total discharged air volume was at a factor of 1: 3. With the enlargement of the air gap according to the present invention up to about 9 mm, the ratio is increased to more than 1: 4, z. B. 1: 5 enlarged. Thus, the problem of a whereabouts of Rolling medium particles on the belt significantly reduced, whereby the quality of the belt is significantly improved. Further advantages of the roller arrangement correspond to the advantages mentioned above with reference to the claimed belt deflector. The belt deflector according to the invention does not have to be approached position-controlled; usually a predefined stop is enough. However, this is dependent on the entire geometry, in particular the roll grinding due to roll wear. The belt deflector according to the invention does not necessarily have to be fastened to a movable adjustment device in order to be able to be moved out of the stator window during a roll change. For the wear-intensive environment of a hot rolling mill, a stationary arrangement of the strip deflector according to the invention between the work roll chocks in the respective roll stand is recommended. The belt deflector according to the invention is suitable both for employment on the upper work roll as well as for employment on the lower work roll in a roll stand.

To increase the sealing effect, it may be useful in certain cases, distributed on the circumference of the roller to arrange at least two inventive Bandabweiser (one above the other). The use of several of the invention Bandabweiser is recommended z. B. in the outlet / on the outlet side of a roll stand, if there is an outlet side roll cooling, because then a lot of cooling medium must be removed at the outlet side.

Further advantageous embodiments of the invention are the subject of the dependent claims.

Figur 1

einen Querschnitt durch die erfindungsgemäße Walzanordnung mit dem erfindungsgemäßen Bandabweiser gemäß einem ersten Ausführungsbeispiel;

Figur 2

die erfindungsgemäße Walzanordnung gemäß einem zweiten Ausführungsbeispiel; und

Figur 3

die erfindungsgemäße Walzanordnung in einer perspektivischen Ansicht gemäß einem dritten Ausführungsbeispiel

zeigt.The description is attached to three figures, wherein

FIG. 1

a cross section through the rolling assembly according to the invention with the tape deflector according to the invention according to a first embodiment;

FIG. 2

the rolling arrangement according to the invention according to a second embodiment; and

FIG. 3

the rolling arrangement according to the invention in a perspective view according to a third embodiment

shows.

The invention will be described below with reference to the above FIGS. 1 to 3 described in detail in the form of embodiments. In all figures, the same technical elements are designated by the same reference numerals.

In FIG. 1 the roller arrangement according to the invention can be seen, according to which the belt deflector 100 according to the invention is employed against the bale of a roller 300. At the bottom of the FIG. 1 is tangential to the roll barrel to be rolled or rolled metal strip 200 to recognize. The belt deflector 100 is set at a distance from its main body 110 to the roller 300. The gap width d is, for example, 1 to 9 mm.

The band deflector 100 basically consists of the main body 110, in which at least one compressed air chamber 114 and a nozzle 116, which is connected to the compressed air chamber in a flow-conducting manner, are formed for discharging compressed air against the ball of the roller 300. The compressed air is from a compressed air source 118, see FIG. 3 , which is flow-connected to the compressed-air chamber 114. The flow-conducting connection between the compressed-air chamber 114 and the nozzle 116 may be formed, for example, in the form of an intermediate channel 122.

The nozzle 116 consists of a first nozzle channel section 116-I connected in flow communication with the compressed-air chamber 114 and one, the first

Nozzle channel section in the flow direction R of the compressed air downstream second nozzle channel section 116-II. The first nozzle channel section 116-I can either be formed directly as an extension of the compressed-air chamber 114 or be conductively connected to the compressed-air chamber 114 via an intermediate channel 122.

Specifically, the first nozzle channel portion 116-I consists of two, preferably parallel, side walls 116-I-1; 116-I-2, wherein a first side wall 116-I-1 is referred to as facing a tip 112 of the base body 110, while the other opposing side forest 116-I-2 is referred to as facing away from the tip 112 of the base body.

In the transition from the first to the second nozzle channel section, the side wall 116-I-1 facing the tip 112 of the main body 110 is bent to form the tip 112 of the main body, forming a first tear-off edge 117.

Between the stepped first tear-off edge 117 and the tip 112 of the main body 110, a drop-shaped, convexly curved flow guide contour 120 is preferably formed. The Strömungsleitkontur 120 is preferably with a concave curvature, which is preferably arcuate, smooth, ie without the formation of kinks in the tip 112 of the base body 110 via. The curvature of the Strömungsleitkontur 120 can be made smaller the smaller an angle α between the flow direction R in the first nozzle channel portion 116-I and a connecting line g between the tip 112 of the base body and the first tear-off edge 117; please refer FIG. 2 ,

With a suitable construction, as an alternative to the angle α, the angle between the direction of the first nozzle channel section 116-I and the intermediate channel may also serve as an indication of the height of the curvature of the flow guide contour 120. At the in FIG. 1 shown

Embodiment is formed between the first nozzle channel portion 116-I and the intermediate channel 122 a right angle. In contrast, in the in FIG. 2 shown embodiment, an acute angle formed between the first nozzle channel portion 116-I and the intermediate channel 122. The curvature of the Strömungsleitkontur 120 can therefore at the in FIG. 2 embodiment shown to be less pronounced than in the FIG. 1 shown embodiment.

The second nozzle channel section 116-II forms the extension of the first nozzle channel section and is substantially defined or delimited by the extension of the side 112-I-2 facing away from the tip 112 of the base body in the flow direction R beyond the height of the tear edge 117. The side wall 116-I-2 facing away from the tip of the base body is bent away from the tip 112 of the belt deflector, forming a second tear-off edge 119 at the end of the second nozzle channel section 116-II.

It is important that both the first tear-off edge 117 and the second tear-off edge 119 form a sharp edge with the smallest possible radius of curvature to ensure that the air flow at the two tear-off edges does not follow the bent shape of the base body in these regions due to the Coanda effect Instead, in its original flow direction, it continues to flow on the roll bales or at least tangentially along the surface of the roll bale.

The side walls facing away from the tip 112 of the main body 110 may be uniformly formed in the region of the first nozzle channel section 116-I and the second nozzle channel section 116-II in the form of a single common plane. Alternatively, the said side wall in both nozzle channel sections or else only in the second nozzle channel section may be slightly convex, bent away from the tip 112, as far as the second tear-off edge. However, the convex curvature may then especially in the area of the second nozzle channel portion 116-II up to the second tear-off edge 110 out possibly so strong that the air flow - at a given employment of the belt deflector 100 against the bale of the roller 300 - when exiting the nozzle still impinges on the surface of the roller 300 or at least tangentially flows along the bale. In other words, the convex curvature in this region may only be formed to such an extent-given a position of the belt deflector against the roller-that a tangent to the side wall 116-II of the second nozzle channel section at the second tear-off edge still hits or hits the roll bale at least tangent.

The tip 112 of the band deflector 100 is preferably formed as a separate component detachably connected to the base body. This is advantageous because the tip is subject to heavy wear in practice. It can be made of metal or plastic.

In FIG. 3 It can be seen that the nozzle may be formed, for example, slit-shaped. Alternatively, however, it may also be formed from a multiplicity of individual nozzles or individual bores, which are connected in flow-conducting manner to the compressed-air chamber 114.

In FIG. 3 Furthermore, it can be seen that the compressed air chamber 114 may be formed in the form of a plurality of N individual compressed air chambers 114-n with 1 ≤ n ≤ N, wherein each of the individual compressed air chambers is provided for supplying a certain portion of the nozzle 116 in the width direction with compressed air. For this purpose, the individual compressed air chambers 114-n are preferably each connected via a separate supply line to the compressed air source 118. Each of the supply lines is preferably individually shut off via its own shut-off valve 115-n with 1 ≤ n ≤ N. The advantage of this embodiment is that the compressed air supply to the nozzle 116 is variable in the width direction
has been adapted to the width of each to be rolled or rolled strip 200, has already been described above.

Constructively, the main body 110 of the inventive band deflector can be formed from a lower molded part 110-1 and an upper molded part 110-2.

LIST OF REFERENCE NUMBERS

100

strip deflector

110

body

110-1

lower molding

110-2

upper molding

112

top

114

Compressed air chamber

114-n

Compressed air chamber

115

shut-off valve

116

jet

116-I-1

Side wall

116-I-2

Side wall

116-II

Nozzle channel section

117

first tear-off edge

118

Compressed air source

119

second tear-off edge

120

Strömungsleitkontur

122

intermediate channel

200

tape

300

roller

R

flow direction

α

angle

G

connecting line

N

Total number of compressed air chambers

Claims (13)

1. Strip deflector (100) for contactless deflection of a rolling medium from the surface of a metal strip (200) during rolling of the metal strip, comprising:

   a base body (110), which defines a tip (112), with at least one compressed air chamber (114) and at least one nozzle (116) for issuing compressed air; and

   a compressed air source (118), which is connected in terms of flow with the compressed air chamber (114), for providing compressed air for the compressed air chamber (114) and the nozzle (116),

   wherein the nozzle (116) has a first nozzle channel section (116-1) connected in terms of flow with the compressed air chamber (114) and a second nozzle channel section (116-II) downstream of the first nozzle channel section in flow direction (R),

   wherein the first nozzle channel section (116-I) is formed by a side wall (116-I-1) facing the tip (112) of the base body (110) and an opposite side wall (116-1-2) remote from the tip of the base body,

   wherein at the transition from the first nozzle channel section to the second nozzle channel section the side wall (116-1-1) facing the tip (112) of the base body is bent away towards the tip (112) of the base body (100) so as to form a first separation edge (117), and

   wherein the second nozzle channel section (116-II) is bounded by the continuation of the side wall (116-I-2), which is remote from the tip (112) of the base body, beyond the first separation edge (117) in the flow direction (R);

   characterised in that

   the side wall (116-1-2) 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 channel section (116-II).
2. Strip deflector (100) according to claim 1,
   characterised in that
   the section, which bounds the second nozzle channel section (116-II), of the side wall 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 channel section (116-1) and in the region of the second nozzle channel section (116-II).
3. Strip deflector (100) according to one of the preceding claims,
   characterised in that
   a drop-shaped, convexly curved flow guide profile (120) is formed between the offset first separation edge (117) and the tip (112) of the base body.
4. Strip deflector (100) according to claim 3,
   characterised in that
   the smaller the angle (α) between the flow direction (R) in the first nozzle channel section and a connecting line (g) between the tip (112) of the base body and the first separation edge (117), the smaller the curvature of the flow guide profile is formed to be.
5. Strip deflector (100) according to any one of the preceding claims,
   characterised in that
   the compressed air source (118) is constructed as a compressor for generating compressed air at, for example, 3 bars or as a fan for generating compressed air at, for example, 1.5 bars, wherein the air flow in the nozzle (116) in both cases attains only a subsonic velocity.
6. Strip deflector (100) according to any one of the preceding claims,
   characterised in that
   the strip deflector has in width direction a plurality (N) of pressure chambers (114-n) which are each connected with the compressed air source (118) by way of an individual feed line, wherein each of the feed lines is preferably individually closable by way of a blocking valve (115-n).
7. Strip deflector (100) according to any one of the preceding claims,
   characterised in that
   the nozzle (116) is formed as a slot nozzle over the entire width of the strip deflector (100).
8. Strip deflector (100) according to any one of claims 1 to 6,
   characterised in that
   the nozzle (116) is formed over the entire width of the strip deflector from a plurality of individual nozzles.
9. Strip deflector (100) according to any one of the preceding claims,
   characterised in that
   the tip (112) of the base body (110) of the strip deflector is detachably connected as a separate component with the base body.
10. Strip deflector (100) according to any one of the preceding claims,
    characterised in that
    the tip (112) is made of metal or plastics material.
11. Roll arrangement comprising at least one roll (300) and at least one strip deflector (100) according to any one of the preceding claims,
    characterised in that
    the strip deflector in the region of the tip (112) of the base body (110) is placed at the roll to be spaced by way of a gap with a gap width d of, for example, d = 1 to 9 millimetres.
12. Roll arrangement according to claim 11,
    characterised in that
    two or more strip deflectors (100) are arranged in distribution in circumferential direction of the roll (300).
13. Roll arrangement according to claim 11 or 12,
    characterised in that
    the side wall, which is remote from the tip (112) of the base body (110), of the second nozzle channel section is formed to be convexly curved,
    wherein the convex curvature for a given placement of the strip deflector against the roll is formed to be merely so small that a tangent to the side wall (116-II) of the second nozzle channel section at the second separation edge still contacts the roll body or is at least tangential thereto.

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