NOZZLE DEVICE AND METHOD FOR THE PRODUCTION THEREOF

Description

[0001] The present invention relates to a nozzle device for applying at least one first medium to the surface of a flat body, in particular to the surface of a metal strip. The invention further relates to a method for producing the nozzle device and a use of the nozzle device. Background of the invention:

[0002] When cold rolling metal strip, fluids (emulsions, rolling oils, etc.) are typically used to lubricate the roll gap, which positively influence the rolling process. However, residues of these fluids are undesirable on the surface of the cold-rolled strip as the final product. Strip dryness is a key quality criterion of paramount importance for customers.

[0003] Nozzle devices for blowing off moisture, particularly from metal strips, are generally known on the market. However, these often do not produce satisfactory results. For example, conventional blower beams for drying surfaces are known in the prior art. These blower beams typically consist of a compressed air distribution pipe with compressed air nozzles mounted on it. Such blower beams have the disadvantage that the blower cones of the individual nozzles influence each other in the overlapping area. This can lead to streaks of residual moisture on the surface of the strip in the overlapping area of the blower cones. To reduce this effect, the relevant nozzle manufacturers recommend arranging several blower beams in series, each with different nozzle arrangements.However, this approach does not solve the actual problem, but rather simply reduces the overall effect on the band surface via the blow bars arranged one behind the other.

[0004] In addition to blow bars, so-called "air knives" are also known. These air knives create a continuous compressed air curtain that preferably extends across the entire width of the produced metal strip and beyond. While the negative effects described for classic blow bars due to the interference of the various blow cones do not occur here, the familiar air knives with straight slot nozzles have the disadvantage that they cause the liquids to be blown off to build up in front of the compressed air curtain. If the accumulated liquid pool becomes too large, some of the accumulated liquid may penetrate the compressed air curtain, resulting in a suboptimal drying result on the surface of the metal strip. Since the liquid is not actively directed to the edges of the strip, a straight slot nozzle must also be continuously pressurized with compressed air.In reversing cold rolling mills, however, a large amount of emulsion is present on the strip surface shortly after the reversal of the rolling direction, which must be removed.

[0005] Known V-shaped blow bars, such as those described in Chinese patent applications CN 2010 76872 Y and CN 2012 75559 Y, as well as in Chinese utility model application CN 212419119 U, attempt to compensate for precisely this disadvantage. However, the functional principle of the V-shaped blow bars disclosed therein is based—as with conventional blow bars—on overlapping blow cones that influence each other. This can lead to the aforementioned streaky residual moisture on the surface in the overlapping areas. Furthermore, it has been shown that the theoretical blow cones of the nozzles of the blow bars determined under laboratory conditions do not correspond to those in actual rolling operations. This is due to various boundary conditions in the actual application environment, e.g., fume extraction, high strip speeds, crossflows at the edges of the body, turbulence caused by rotating components, etc.This makes it difficult to achieve optimal alignment of the nozzles with well-coordinated overlaps, and commissioning problems often occur at these points.

[0006] US patent application US 2019 / 0076856 A1 discloses a nozzle device that essentially consists of a compressed air supply channel that divides into two branches at its end. Compressed air nozzles are mounted at the free ends of these branches for discharging compressed air in different directions. This nozzle device is intended for separating a seam severed from a metal strip from a main part of the metal strip.

[0007] British patent GB 1,010,863 discloses a nozzle device with a V-shaped nozzle slot for drying or removing residual moisture from a metal strip using compressed air.

[0008] The Korean publication KR 2010 0059 414 A also discloses a nozzle device for spraying a metal strip with a plurality of spray nozzles, wherein the supply lines branch out to these individual spray nozzles.

[0009] Finally, international patent application WO 03550 A1 discloses a nozzle device according to the preamble of claim 1.

[0010] The invention is based on the object of developing a known nozzle device with an elongated primary nozzle and a use for the nozzle device in such a way that residual moisture present on the surface of a flat body is removed according to its distribution over the width of the body.

[0011] This object is achieved for the nozzle device by the subject matter of patent claim 1.

[0012] The terms "flat body" and "flat product" are used synonymously below.

[0013] The claimed V-shaped design of the primary slot ensures that the liquids to be removed from the surface do not accumulate in front of the compressed air curtain of the slot nozzle, but are actively removed toward the edges of the belt. This achieves optimal drying results because the claimed V-shape effectively prevents excessive accumulation of liquid in front of the compressed air curtain of the elongated slot nozzle and thus a breakthrough of the liquid through the curtain, consisting of at least the first medium. This prevents, in particular, the retention of residual moisture, especially in the form of streaks on the surface.

[0014] In addition, the V-shape of the slot nozzle offers the advantage that it does not need to be pressurized with compressed air continuously, but only for a short time until the liquid pool in front of the curtain has been removed.

[0015] According to a first embodiment, in the nozzle device according to the invention, secondary nozzles with secondary slots are preferably formed adjacent to and parallel to the primary nozzle with the primary slot on both sides for discharging secondary jets of a second medium onto the surface. The secondary jets preferably serve to stabilize the primary jet. The curtain then consists of the first and second medium.

[0016] According to a further embodiment, the first and second media can be the same; for example, both media can be air. However, the first medium can be compressed air, for example, and the second medium can be drawn-in ambient air. Both media are preferably gaseous.

[0017] According to a further embodiment of the invention, at least the primary slot is not interrupted over its entire length, in particular also in the region of the bend or the curvature of its V-shaped configuration, but is formed continuously.

[0018] The elongated primary slot nozzle can be configured over its entire length in the form of a plurality of slot nozzle segments, which are connected to one another at their end faces so that the primary slot is continuous. Further advantageous embodiments of the nozzle device according to the invention are the subject of the dependent claims.

[0019] Finally, the above-mentioned object is achieved by a claimed use for the nozzle device according to the invention according to claim 6. The description is accompanied by three figures, wherein Figure 1 shows the nozzle device according to the invention during the blow-off of moisture from a metal strip in a first operating mode; Figure 2 shows the nozzle device according to the invention during operation of the primary slot in a second operating mode, which does not fall under the wording of the claims; and Figure 3 shows a cross-sectional view of the nozzle device according to the invention.

[0020] The invention is described in detail below with reference to the figures mentioned in the form of exemplary embodiments. In all figures, identical technical elements are designated by identical reference numerals.

[0021] Figure 1shows the nozzle device 100 according to the invention for applying a first medium to the surface of a flat body, here, for example, a metal strip 300. The first medium has the reference numeral 210. The nozzle device 100 consists of an elongated primary nozzle 110 with a primary slot that preferably extends continuously across the entire width B of the primary nozzle 110. The width of the primary nozzle should be selected such that it is wider than the width B of the metal strip 300 to be dried.

[0022] Within the nozzle device 100, behind the primary slot 112, a pressure chamber 114 is formed, which is in fluid communication with the primary slot 112 for dispensing a primary jet 137 of the first medium in the form of a curtain onto the surface of the metal strip 300. The pressure chamber 114 preferably extends over the same length or width as the primary nozzle 112. The pressure chamber typically has a slot-shaped outlet, which also extends over the length of the primary slot and which is either identical to the primary slot 112 or which opens directly into the primary slot to supply the primary slot over its entire length with the first medium.

[0023] According to the invention, the primary slot is V-shaped, similar to a snowplow. The V-shaped configuration offers the advantage that liquid that collects in front of a curtain formed at least by the primary nozzle 112 by the discharge of the first medium is immediately diverted to the edge of the flat body 300, in particular the metal strip. The primary slot 112 is preferably continuous, i.e., uninterrupted, over its entire length and also in the region of its V-shaped configuration, i.e., in the region of its kink or curvature. Accordingly, the curtain generated by it, consisting of the first medium, is also continuous over its entire length.

[0024] To supply the pressure chamber 114 and the primary slot 112 with the first medium, at least one supply line 118 is provided, which, on its way to the pressure chamber 114—distributed across its width—increases into a plurality of supply lines 119. Due to the increasing branching, the compressed air supply is aerodynamically optimized and ensures a constant dynamic pressure in the primary nozzle across the width. This makes a constant compressed air curtain across the width possible. A plurality of blow-off zones are formed across the width of the elongated spray nozzle, with each of the blow-off zones being represented by at least one, but typically by a plurality of branched supply lines 119, which open directly into the pressure chamber. Valves 121 are provided in the branches 119 for individually controlling the inflow of the first medium into the individual blow-off zones. Figure 1It can be seen that in the nozzle device 100, three blow-off zones I, II and III are formed. Figure 1 In the embodiment shown, blow-off zone II is switched off, while blow-off zones I and III are switched on (= first operating mode).

[0025] In the Figure 1 In the example shown, switching off the blow-off zone II can make sense, because, as shown in Figure 1 As can still be seen, the surface of the metal strip is only moist in its edge area, while it is already dry in the middle of the metal strip. The distribution of dryness across the width B of the metal strip is detected by a moisture detector 400, which generates a corresponding measurement signal. The blow-off zones I, II and are then switched on or off according to the moisture distribution across the width B of the metal strip 300 represented by the measurement signal. Figure 1In the embodiment shown, the drying of the surface in the middle of the metal strip 300 can be achieved by a Figure 1 A drying device (not shown), e.g., a dry strip system, may be implemented, which is mounted upstream of the nozzle device 100 and preferably also upstream of the moisture detector 400. In the Figure 1 In the embodiment shown, the nozzle device 100 according to the invention is used primarily for removing residual moisture, in particular residual emulsion, on the upper side at the edge of the metal strip, which has remained there, for example, after a previous rolling pass of the metal strip and optionally also after its first drying by the dry strip system.

[0026] The control of the valves 121 is carried out via a control device 500 in accordance with the measurement signal output by the moisture detection device 400, which represents the distribution of moisture across the width B of the flat body, in particular the metal strip. This means that the greater the amount of (residual) liquid still present on the strip indicated by the measurement signal for a width range, the stronger the blow-off is set for this width range. As shown in Figure 1 As can be seen, the nozzle device 100 according to the invention is positioned during operation with respect to the metal strip 300 to be dried such that its V-shaped configuration is directed against the rolling direction, i.e., against the transport direction of the metal strip. Only then can the desired discharge of the liquid toward the edge of the metal strip be ensured.

[0027] The terms "moisture" and "liquid" are used synonymously in this description.

[0028] In Figure 2 The nozzle device 100 according to the invention is shown again. In contrast to Figure 1 is in the Figure 2 However, it can be seen that all three blow-off zones I, II and III are activated, ie they are supplied with the first medium, for example compressed air, via the supply line 118. This corresponds to a second operating mode, which does not fall under the wording of the claim. For such use, no valves 121 in branched supply lines 119 are required, as in Figure 1 Such valves can be used in the Figure 2 shown embodiment can be saved.

[0029] Figure 3 shows a cross section through the device 100 according to the invention. In Figure 3Firstly, the primary nozzle 110 can be seen with the pressure chamber 114, which opens into the primary slot 112 with its slot-shaped outlet. The primary nozzle generates the primary jet 113. Secondary nozzles 115 are preferably formed adjacent to and parallel to the primary slot 112 of the primary nozzle 110 on both sides, each with a secondary slot 116 that is also V-shaped over its length for emitting secondary jets 117 of a second medium 220 onto the surface of, for example, the metal strip 300. The secondary jets 117 primarily serve to stabilize the primary jet 113. The secondary nozzles 115 can in turn each be fed with the second medium from a plurality of tertiary nozzles 200, wherein the output flows of the tertiary nozzles are collected in the secondary nozzles 115 or bundled to form the secondary jet 117.In addition to the flows from the tertiary nozzles 200, the channels of the secondary nozzles 115, in conjunction with the outer surface of the nozzle device 100, are designed so that larger quantities of air from the surroundings of the nozzle device 100 are drawn into the channels of the secondary nozzles 115, amplifying the secondary jets 117. The intake of ambient air can occur due to the Coanda effect. When the primary nozzle and the secondary nozzles operate in parallel, the resulting curtain consists of both the first and second medium.

[0030] The nozzle device 100 according to the invention, with the formation of the pressure chamber 114, with the supply line 118, with the branched supply lines 119, and preferably also with the valves 121 in the branched supply lines, is preferably manufactured in one piece using additive manufacturing, in particular using a 3D printing process. In this way, the nozzle device 100, with its many cavities, can be manufactured very easily and integrated. It can be made, for example, from metal or plastic. The nozzle device made of plastic is significantly lighter than a comparable nozzle device 3D-printed from metal, which simplifies its assembly and allows the actuators required for its positioning to be designed smaller and thus more cost-effectively. Finally, metal parts tend to form condensation on their surfaces. This effect generally does not occur with plastic parts due to their lower thermal conductivity. List of reference symbols

[0031] 100Nozzle device 110Primary nozzle 112Primary slot 113Primary jet 114Pressure chamber 115Secondary nozzle 116Secondary slot 117Secondary jets 118Inlet line 119Feed line 121Valve 200Tertiary nozzles 210First medium 220Second medium 300Flat product, especially metal strip 400Moisture detection device 500Control device BWidth of the metal strip I, II, III blow-off zones

Claims

1. Nozzle device (100) for application of at least a first medium (210) to the surface of a flat product, particularly the surface of a metal strip (300), comprising: an elongate primary nozzle (110) with a V-shaped primary slot (112), which preferably extends continuously over the entire length of the primary nozzle and which is in fluid-conducting connection with a pressure chamber (114) in the interior of the nozzle device, for delivery onto the surface of a primary jet (113) in the form of a curtain consisting at least of the first medium, wherein at least one feed line (118) for supply of the pressure chamber (114) with the first medium is present, characterised in that the feed line towards the pressure chamber is increasingly branched off into a plurality of feed lines (119) distributed over the width (B) thereof; a plurality of blowing-away zones is formed over the width (B) of the elongate spray nozzle, wherein each of the blowing-away zones is represented by at least one, but typically a plurality, of the branched-off feed lines ('119), which open directly into the pressure chamber (114); a moisture detection device (400) is provided for generating a measurement signal which represents the distribution of the moisture over the width (B) of the flat body, particularly the metal strip; valves (12) are provided in the branched-off feed lines (119); and a control device (500) is provided for individual control of the flow of the first medium into the individual blowing-away zones by controlling the valves (121) as setting elements in accordance with measurement signal delivered by the moisture detection device.

2. Nozzle device (100) according to claim 1, characterised in that a respective secondary nozzle (115) with a secondary slot (116), which is also V-shaped, is formed preferably on either side of and adjacent to and running parallel to the primary slot (112) of the primary nozzle (110) for delivery of secondary jets (117) of a second medium (220) to the surface for stabilisation of the primary jet, wherein the curtain is then formed from the first medium and the second medium.

3. Nozzle device (100) according to one of the preceding claims, characterised in that at least the primary slot (112) of the primary nozzle (110), but preferably also the at least one secondary slot, is or are uninterrupted over the entire length thereof, particularly even in the region of the bend or curve of the V-shaped formation thereof.

4. Nozzle device (100) according to any one of the preceding claims, characterised in that the elongate primary nozzle (110) is constructed over the length thereof in the form of a plurality of primary nozzle segments which are so connected together at their ends that the primary slot is continuous.

5. Nozzle device according to any one of the preceding claims, characterised in that the pressure chamber (114) of the primary nozzle extends at least substantially over the same length as the primary slot; and the pressure chamber has a slot-shaped outlet which preferably extends over the entire length of the primary slot and which is identical with the primary slot or which opens directly into this for supply of the primary slot over its entire length with the first medium.

6. Use of the nozzle device according to any one of the preceding claims for removal of residual moisture, particularly residual emulsion, on the lower side and / or upper side at the edge of a metal strip, for example on the inlet side of a roll stand, which still remains there after a previous rolling pass of the metal strip and after preceding drying thereof by a dry-strip system (DS system).