EP3429771B1 - Device and method for descaling a workpiece - Google Patents

Description

The invention relates to a device for descaling a workpiece according to the preamble of claim 1 and a corresponding method according to the preamble of claim 9.

For descaling workpieces, in particular hot rolled material, it is known in the prior art to spray high-pressure water onto the surfaces of the workpiece. For a complete and therefore complete descaling of the surfaces of the workpiece, the high-pressure water is usually sprayed out of a plurality of nozzles in a scale washer. In this context, a scale washer in a hot rolling mill is an assembly that is used to remove scale, i.e. H. of impurities from iron oxide, is provided from the surface of the hot rolling stock.

In the field of hot rolling production, monitoring or inspection of the surfaces of a hot rolling stock transported in one direction of movement has only taken place at the end of the rolling process. Here, a scale washer, which is arranged upstream of or in relation to the direction of movement upstream of a final scaffold, is usually operated at maximum pressure and volume flow for the high-pressure water. This is done for the purpose of achieving the most descaling possible on the surfaces of the hot rolled material. A disadvantage of such a mode of operation of a scale washer is the great need for energy to produce high-pressure water.

Out JP-10 282029 A a method is known for measuring the thickness of a steel plate and for determining the nature of its surface. An X-ray detector is used here.

Out KR 144 3097 B1 a device for detecting scale on a hot rolled product is known. In this device, a scale detection device is used, which is based on the principle of temperature measurement and for this purpose comprises a pyrometer.

Out DE 198 17 002 A1 A device for descaling semi-finished products is known, which has a nozzle device, by means of which a fluid is applied under high pressure to the surface of the semi-finished product moved relative to the nozzle device. To equalize the descaling impact pressure, means are provided with which the strip profile can be detected directly, the height of the nozzle device being dependent on this.

Out WO 2014/191168 A1 a generic device according to the preamble of claim 1, and a generic method according to the preamble of claim 9 are known.

In the previously known systems and methods for descaling hot rolled material, a surface inspection is only installed at the end of the rolling train. Such a surface inspection is spatially far removed from a scale washer and, in particular in terms of process technology, is not connected to the scale washer. If it should be determined by means of the surface inspection that the hot rolled material has surface defects, several production steps, in particular rolling processes, have already been carried out. The consequence of this is that a clean assignment of possible scale defects to the detected surface defects is not possible or is only possible to a limited extent. In other words, in the systems for descaling hot rolled products known to date, it is at least difficult, if not impossible, to reliably identify surface defects as scale residues. In any case, the previously known approaches to descaling workpieces are subject the disadvantage that a classification into primary and secondary scale errors as well as the distinction between rolled-in residual scale due to a previously inadequate descaling and scale chips falling down in the course of the rolling process cannot be realized.

The object of the invention is to optimize the descaling of workpieces with regard to the surface quality and also to reduce the need for energy and high-pressure liquid to a necessary minimum.

This object is achieved by a device for descaling a workpiece with the features specified in claim 1, and by a method according to claim 9. Advantageous developments of the invention are defined in the dependent claims.

The invention provides a device for descaling a workpiece, preferably a hot rolled product, which is moved relative to the device in one direction of movement. For this purpose, the device comprises at least one first jet nozzle arrangement with a plurality of jet nozzles, from which a liquid, in particular water, can be applied to a surface of the workpiece under high pressure. Furthermore, the device comprises a control device and a surface inspection device connected to the control device by means of signals, which is arranged downstream of the jet nozzle arrangement with respect to the direction of movement of the workpiece and enables the detection of scale on the surface of the workpiece. The surface inspection device is arranged directly adjacent to the jet nozzle arrangement. In terms of programming, the control device is set up in such a way that the specific energy input with which a surface of the workpiece is acted upon by the liquid discharged from the jet nozzles can be regulated by means of the control device as a function of the signals of the surface inspection device, and that a surface quality is based on the signals of the surface inspection device determined for the workpiece and compared with a predetermined target value. Here, the specific energy input regulated in such a way that it is increased if the surface quality of the workpiece falls below the predetermined target value and is decreased if the surface quality of the workpiece exceeds the predetermined target value.

In the same way, the invention provides a method for descaling a workpiece, preferably a hot rolled product, which is moved in one direction of movement relative to a blasting nozzle arrangement with a plurality of blasting nozzles. To descale the workpiece, a liquid, in particular water, is sprayed from the jet nozzles onto a surface of the workpiece under high pressure. To carry out the method, a control device is provided which is connected to the jet nozzle arrangement and to a surface inspection device in terms of signal technology. By means of the surface inspection device, a surface of the workpiece is checked with respect to the direction of movement of the workpiece - downstream of the jet nozzle arrangement and immediately adjacent to the jet nozzle arrangement. The specific energy input with which a surface of the workpiece is acted upon by the liquid discharged from the jet nozzles is regulated by the control device as a function of the signals from the surface inspection device, a surface quality for the workpiece being determined on the basis of the signals from the surface inspection device and with a predetermined target value is compared. Here, the specific energy input is regulated in such a way that it is increased if the surface quality of the workpiece falls below the predetermined target value, and is reduced if the surface quality of the workpiece exceeds the predetermined target value.

The invention is based on the essential finding that a surface inspection device is arranged close to the jet nozzle arrangement. In this regard, the feature "close to location" in the sense of the present invention means that the surface inspection device - in relation to the direction of movement with which the workpiece is moved past the jet nozzle arrangement at a feed rate - is positioned downstream of the jet nozzle arrangement and immediately adjacent thereto . This makes it possible to see the result of the Applying a liquid under high pressure to the surfaces of the workpiece and to monitor and, if necessary, influence the resulting descaling quality, in particular before the workpiece undergoes further production steps such. B. undergoes further rolling operations. On the basis of the signals from the surface inspection device, a reference variable is thus obtained, with which subsequently a customized control of the specific energy input is possible, with which descaling of the workpiece is achieved.

The specific energy input is determined according to the present invention from the impact pressure with which the liquid impinges on a surface of the workpiece, and the specific volume flow per width of the workpiece, i.e. the volume flow of the liquid sprayed onto the workpiece divided by the spray width in relation to the direction of movement of the workpiece. The impact pressure is dependent on the pressure with which the liquid is supplied to the jet nozzles, the volume flow sprayed out, and the distance of the jet nozzles from the surface of the workpiece. Furthermore, the specific energy input depends on the feed rate at which the workpiece is moved in the direction of movement. The specific energy input, depending on the signals of the surface inspection device, can be changed by adapting the parameters mentioned above, namely by means of the control device, as will be explained in detail below.

According to the invention, the control device is set up in terms of program technology in such a way that the specific energy input is regulated on the basis of the signals of the surface inspection device. For this purpose, the control device, namely on the basis of the signals from the surface inspection device, determines a surface quality for the workpiece and then compares it with a predetermined target value. If it is subsequently determined by means of the control device that the surface quality of the workpiece falls below the predetermined target value, the specific energy input is then increased. Conversely, this means that if the surface quality of the workpiece exceeds the predetermined target value, then the specific energy input is reduced accordingly. Such a setting or adaptation of the specific energy input, based on the signals of the surface inspection device, is carried out in a controlled manner according to a preferred embodiment of the invention, ie by providing a corresponding control loop in the control device.

The actuators for controlling and / or regulating the specific energy input are the system pressure of the descaling, the height adjustment of the jet nozzles, i.e. the change in the distance of the jet nozzles to the surface of the workpiece, the connection / disconnection of an additional jet nozzle arrangement, and the feed speed of the workpiece to disposal.

In order to reduce the specific energy input just mentioned, namely in the event that the surface quality of the workpiece ascertained by means of the surface inspection device exceeds a predetermined target value, a smaller amount of high-pressure liquid is advantageously required, and thereby a reduced cooling of the workpiece is also achieved. Such reduced cooling can be used to lower a furnace temperature or to lower the energy requirement for a subsequent rolling process, i. H. downstream of the jet nozzle arrangement. Furthermore, the final temperature of the product is increased by a reduced cooling of the workpiece, as a result of which the product range can be expanded to lower final pressures.

As explained, a possible reduction in the specific energy input or the descaling pressure, at least to a pressure value that is just sufficient to achieve the predetermined target value for the surface quality of the workpiece, leads to the advantage of a lower energy requirement for generating the high pressure Descaling liquid. In the course of this, the wear on system components of the device according to the invention or of the entire descaling system is also advantageously reduced. This applies both to the jet nozzles themselves and to a large extent to the pumps, pipelines and all parts that come into contact with the media. In addition, there is the advantage of extended maintenance intervals and thus of lower maintenance costs, due to a reduced abrasion effect of the high-pressure liquid on all surrounding materials due to the reduced pressure.

By regulating the specific energy input, it is possible to react immediately to detected surface defects of the workpiece, ie to remaining scale on the workpiece, namely by a suitable increase in the specific energy input by the actuators mentioned above. This can effectively avoid that residual scale Further production steps such as, in particular, rolling processes which follow the workpiece downstream of the jet nozzle arrangement are rolled into the surface of the workpiece. In addition to maintaining a desired quality level for the workpiece, this can avoid that parts of the production - if z. B. residual scale would not be recognized or removed - must be scrapped.

In an advantageous development of the invention, the device comprises a high-pressure pump unit which is connected to the control device by means of signals and is in fluid communication with the jet nozzles of the jet nozzle arrangement. This high-pressure pump unit can be controlled, preferably regulated, by means of the control device in order to change the pressure with which the liquid is supplied to the jet nozzles. As a result of this changed pressure for the liquid, the descaling or impact pressure with which the liquid bounces on a surface of the workpiece also changes accordingly in order to descale the workpiece as desired. In view of the dependency explained above, this also changes the specific energy input with which the liquid is applied to the surface of the workpiece.

The high pressure pump unit can have a plurality of individual pumps. When the high-pressure pump unit is activated by means of the control device, it can be provided that a further pump is switched on in the event of a pressure increase, or that one of the pumps used is switched off in the event of a desired pressure reduction.

In an advantageous development of the invention, the high-pressure pump unit can be equipped with at least one frequency regulator, or preferably with a plurality of frequency regulators. A pump or the pumps of the high-pressure pump unit is / are connected to an electrical supply network via this frequency controller, the respective frequency controller being connected to the control device in terms of control technology. Accordingly, it is possible to control or regulate the frequency controller of the high-pressure pump unit by means of the control device such that the pressure with which the liquid is supplied to the jet nozzles of a jet nozzle arrangement is also set or changed to a small extent or with small increments, preferably also continuously can be.

Additionally or alternatively, according to an advantageous development of the invention, it can be provided that a distance which the jet nozzle arrangement has from the surface of the workpiece is controlled, preferably regulated, changed by means of the control device, namely as a function of the signals of the surface inspection device. This can be done in that the jet nozzle arrangement is attached to a height-adjustable holder with an actuator, the actuator being signal-connected to the control device. If the surface quality determined by the control device on the basis of the signals from the surface inspection device falls below a predetermined target value, the distance between the jet nozzle arrangement and the surface of the workpiece can be reduced by suitable control of the actuator by means of the control device, with the result that the impact pressure is thereby reduced the liquid or the descaling pressure increases. In this regard, it goes without saying that such a change in the spacing of the jet nozzle arrangement takes place only to the extent that a desired spray pattern of the jet nozzles remains on the surface of the workpiece.

In an advantageous development of the invention, the feed rate of the workpiece can be adapted to adapt the specific energy application in accordance with the control device, provided that the overall process allows it.

Scale or other particles occasionally block individual jet nozzles. According to the prior art known so far, this can only be done at a much later point in time due to scale errors in the final monitoring are found, combined with the disadvantage that a few tons of hot rolled steel or steel have already been produced with errors. In contrast, such a blockage of a jet nozzle can be recognized directly after the occurrence of this error by a direct monitoring of the descaling result, namely on the basis of the signals of the surface inspection device, which is arranged close to the jet nozzle arrangement, and a corresponding maintenance signal can be output to the control device or a control center become.

Another advantage of the present invention is that, thanks to a reliable signal for the surface quality or surface quality of the workpiece, which is detected immediately downstream of the jet nozzle arrangement, it is possible for the device to use only a single pair of a jet nozzle arrangement, i . H. above and below the workpiece. In other words, a device according to the invention can be limited to such a pair of jet nozzle arrangements, as a result of which considerable investment costs for the likewise reduced high-pressure pump unit and associated connecting pipelines can be saved. This in turn results in a space saving for the high-pressure pump unit, a reduction in the roller table and a relief of the water management, which supplies the high-pressure pump unit with liquid.

Fig. 1

eine prinzipiell vereinfachte Seitenansicht einer erfindungsgemäßen Vorrichtung,

Fig. 2

eine prinzipiell vereinfachte Seitenansicht einer Strahldüsen-Anordnung nach einer weiteren Ausführungsform der Erfindung,

Fig. 3

eine prinzipiell vereinfachte Draufsicht auf eine erfindungsgemäße Vorrichtung nach einer weiteren Ausführungsform,

Fig. 4

eine vereinfachte Seitenansicht eines Rotorkopf-Paars, das Teil einer Vorrichtung von Fig. 3 sein kann, und

Fig. 5

ein Ablaufdiagramm zur Ausführung der vorliegenden Erfindung.

Embodiments of the invention are described in detail below with reference to the schematically simplified drawing. Show it:

Fig. 1

a principally simplified side view of a device according to the invention,

Fig. 2

a basically simplified side view of a jet nozzle arrangement according to a further embodiment of the invention,

Fig. 3

a basically simplified top view of a device according to the invention according to a further embodiment,

Fig. 4

a simplified side view of a pair of rotor heads, part of an apparatus of Fig. 3 can be, and

Fig. 5

a flowchart for carrying out the present invention.

Below, with reference to the Figures 1 to 5 various embodiments of the invention are described in detail. In the figures, the same technical features are denoted by the same reference numerals. Furthermore, it is pointed out that the representations in the drawing are simplified in principle and in particular are shown without a scale. Cartesian coordinate systems are entered in some figures for the purpose of spatial orientation for a device according to the invention in relation to a workpiece to be descaled and moved.

A device 10 according to the invention serves for descaling a workpiece 12 which is moved in a direction of movement X relative to the device 10. The workpiece can be hot rolled material that is moved past the device 10. A feed rate at which the workpiece 12 is moved past the device 10 in the direction of movement X is shown in FIG Fig. 1 and in Fig. 2 each symbolized by the arrow "v".

A device 10 according to the invention has a jet nozzle arrangement with a plurality of jet nozzles, from which a liquid, in particular water, is sprayed onto a surface of a workpiece under high pressure. The jet nozzle arrangement can consist of a rotor head ( Fig. 1 ) or from a spray bar ( Fig. 2 ) be formed, as explained in detail below. In both of these embodiments, jet nozzles 16 are provided, from which a liquid 18 (in Fig. 1 simply symbolized with dashed lines) is sprayed under high pressure onto a surface 20 of the workpiece 12 in order to descaling the workpiece 12 in a suitable manner.

In the embodiment of FIG Fig. 1 a jet nozzle arrangement which, as just explained, is in the form of a rotor head 14 which can be rotated about an axis of rotation R. The rotor head 14 is rotated about its axis of rotation R by motor means (not shown), for example by an electric motor. The jet nozzles 16 are attached to an end face of the rotor head 14 which faces the workpiece 12.

The jet nozzles 16 are in the embodiment of FIG Fig. 1 firmly attached to the rotor head 14. Here, the longitudinal axes L of the jet nozzles 16 are aligned parallel to the axis of rotation R of the rotor head 14.

The jet nozzles 16 are designed to be height-adjustable, for example by attaching them to a height-adjustable holder which is arranged in the Fig. 1 and Fig. 2 simplified symbolized by the double arrow "H". The holder H can have an actuator (not shown in the drawing). A distance A, which an end face of the jet nozzles 16 has to the surface 20 of the workpiece 12, can thus be adjusted, if necessary, by actuating the actuator. In the sense of the present invention, this distance A is to be understood as the spraying distance. If this distance A is reduced, the resulting impact pressure of the liquid 18 on the surface 20 of the workpiece 12 increases.

The device 10, such as for the embodiment of FIG Fig. 1 shown comprises a control device 22 and a high-pressure pump unit 24, which is connected to the control device 22 for signaling purposes. The rotor head 14 is connected to the high-pressure pump unit 24 via a connecting line in such a way that the jet nozzles 16 are in fluid communication with the high-pressure pump unit 24 and are therefore supplied with a liquid under high pressure by the high-pressure pump unit 24. With the liquid 18, which is then sprayed under high pressure from the jet nozzles 16 onto the workpiece 12, it is preferably water, without any restriction being limited to the medium water.

The high-pressure pump unit 24 is equipped with a frequency controller 25. This makes it possible, in particular, to control the high-pressure pump unit 24 in a stepless manner by means of the control device 22 in order to be able to change the pressure at which the liquid 18 is supplied to the jet nozzles 16 even in small steps. Further details for such a control of the high-pressure pump unit 24 are set out in detail below.

The device 10 comprises a surface inspection device 26, which - in relation to the direction of movement X of the workpiece 12 - is arranged downstream of the rotor head 14 and close to it. The surface inspection device 26 can be based on a specialized optical measuring principle in which a 3D measurement is carried out for a surface 20 of the workpiece 12 and a height profile for the surface 20 of the workpiece 12 is derived from this. Alternatively, a spectral analysis is carried out on the surface 20 of the workpiece 12 by means of the surface inspection device 26. The surface inspection device 26 is also connected to the control device 22 in terms of signal technology. Thus, by means of the surface inspection device 26 and a corresponding evaluation in the control device 22, scale or residual scale can be detected on the surface 20 of the workpiece 12. For this purpose, the surface inspection device 26 is designed such that both an upper side and an underside of the workpiece 12 are monitored.

The signaling connection between the control device 22 and the high-pressure pump unit 24 is shown in FIG Fig. 1 designated by reference numeral 23.1. The signal connection between the control device 22 and the surface inspection device 26 is designated by the reference symbol 23.2. The signaling connection between the control device 22 and the height adjustment H is designated by the reference symbol 23.3. The signal connection between the control device 22 and a device (not shown), by means of which the feed speed v of the workpiece 12 can be set or changed, is identified by the reference symbol 23.4. These connections 23.1, 23.2, 23.3 and 23.4 can either be physical lines or a suitable radio link or the like.

With respect to the control device 22, the high-pressure pump unit 24 and the surface inspection device 26 apply to the embodiment of FIG Fig. 2 the same relationships as for the embodiment of Fig. 1 , these technical components for simplification in Fig. 2 are not shown.

Fig. 3 shows a further embodiment of the device 10 according to the invention, namely in a simplified top view. In this embodiment, two jet nozzle arrangements 14.1 and 14.2 are arranged one behind the other with respect to the direction of movement X of the workpiece 12. Each of these jet nozzle arrangements 14.1 and 14.2 is connected to the high pressure pump unit 24, as with reference to FIG Fig. 1 explained. In the embodiment of Fig. 3 the surface inspection device 26 is positioned downstream of the jet nozzle arrangement 14.2. For clarification, it should be pointed out that the representation of Fig. 3 a width of the workpiece 12 extends in the direction y, the axes of rotation R for the rotor heads 14.1 and 14.2 each running perpendicular to the plane of the drawing.

Regarding the embodiment of Fig. 3 may be pointed out separately that the jet nozzle arrangement 14.1 is a pair of rotor heads 28 (cf. Fig. 4 ) can be, wherein the jet nozzle arrangement 14.2 arranged downstream thereof is a spray bar pair 38 (cf. Fig. 2 ) can act. Alternatively, in the embodiment of Fig. 3 the spray bar pair 38 also correspond to the jet nozzle arrangement 14.1, where then the pair of rotor heads 28 is arranged downstream thereof, namely at the location of the jet nozzle arrangement 14.2. Furthermore, it is also possible that the jet nozzle arrangements 14.1 and 14.2 in the embodiment of FIG Fig. 3 both either from a pair of rotor heads 28 ( Fig. 4 ), or each from a spray bar pair 38 ( Fig. 2 ) are formed.

Below are with reference to the Fig. 4 shown and explained a possible arrangement of rotor heads for completion, which in the embodiment of Fig. 3 can be used.

Fig. 4 shows a side view of a pair of rotor heads 28, in which a rotor head 14 is provided above and below the workpiece 12, ie both on its top and on its bottom. It can be seen that the rotor head 14, which is arranged below the workpiece 12, is positioned downstream of the rotor head 14, which is arranged above the workpiece 12, with respect to the direction of movement X of the workpiece 12. This is so that the liquid 18 which is sprayed out of the jet nozzles 16 of the rotor head 14 arranged below the workpiece 12 does not collide with the rotor head 14 arranged above the workpiece 12 if there is no workpiece 12 between these two rotor heads. The in Fig. 4 shown offset between the rotor heads arranged above and below the workpiece 12 does not change the fact that these two rotor heads, in the sense of the present invention, are to be understood as a pair of rotor heads 28. Analog shows Figure 2 the offset of jet nozzles 16 just explained for another jet nozzle arrangement, namely in the form of the spray bar pair 38.

For the representation of Fig. 4 it is additionally pointed out that this can also be a side view of a pair of rotor modules in which a plurality of rotor heads 14 (cf. Fig. 1 ) are combined in the y direction to form a rotor module above and below a workpiece 12.

Regarding the embodiments according to the Fig. 2 and 4th it is pointed out that the individual jet nozzles 16 are connected to a common pressurized water line D, which is connected to the high-pressure pump unit 24. This ensures that the jet nozzles 16 are supplied with high-pressure water.

Fig. 2 shows a simplified side view of a device 10 according to the invention according to a further embodiment. Here, a jet nozzle arrangement of the device 10 is designed in the manner of a so-called spray bar 36, the longitudinal extension of which is transverse (ie in Fig. 2 in the direction of the y-axis) to the direction of movement X of the workpiece 12. The longitudinal extent of a spray bar 36 generally corresponds to a width of the workpiece 12 to be descaled. Along the longitudinal extent of a spray bar 36, a plurality of jet nozzles 16 are arranged, of which only the jet nozzle 16 lying at the front is shown in the illustration in FIG. 7.

In the embodiment of Fig. 2 a spray bar 36 is provided above and below the workpiece 12, which thus form a spray bar pair 38. The jet nozzles 16 of the spray bar pair are arranged on the spray bars 36 at an angle with respect to an orthogonal to the surface 20 of the workpiece 12 such that the liquid 18 which is sprayed out of the jet nozzles 16 has an angle α on the surface 20 of the workpiece 12 strikes.

According to a further embodiment of the invention, a separate surface scanning unit 40 ( Fig. 3 ) may be provided, which is arranged upstream of a jet nozzle arrangement 14 and is connected to the control device 22 in terms of signal technology. Such a surface scanning unit 40 functions electronically and comprises an optical measuring system that can work according to the laser beam principle. If an irregularity should occur on the surface, this is detected by the surface scanning unit 40 and a corresponding one Signal generated, on the basis of which the control device 22 then the actuator of the height-adjustable bracket H (see. Fig. 1 , Fig. 2 ) controls to immediately increase the distance A of the jet nozzle arrangement to the surface of the workpiece 12. This ensures that the jet nozzle arrangement is not damaged if the workpiece 12 should have such an irregularity.

In all of the above-mentioned embodiments, the workpiece 12 is moved past the device 10, namely at a feed rate which is symbolized in the respective figures with "v". By spraying water under high pressure, the surfaces 20 of the workpiece 12 are subjected to a specific energy input E (or "spray energy"), which is determined as follows: $$\mathrm{E}=\mathrm{I.}\cdot \frac{{\dot{V}}_{\mathit{spec}}}{\mathrm{V}}$$

E:

Spezifischer Energieeintrag [kJ/m²]

I:

Aufpralldruck [N/mm²]

V̇_spez:

Spezifischer Volumenstrom pro m Breite des Werkstücks [l/s•m]

v:

Vorschubgeschwindigkeit des Werkstücks [m/s]

Here mean:

E:

Specific energy input [kJ / m ² ]

I:

Impact pressure [N / mm ² ]

V̇ _spec :

Specific volume flow per m width of the workpiece [l / s • m]

v:

Workpiece feed speed [m / s]

Here, the impact pressure with which the liquid 18 impinges on the surface 20 of the workpiece 12 is dependent both on the pressure and the volume with which the liquid is sprayed out of the jet nozzles 16 and on the distance the jet nozzles 16 from the surface 20 of the workpiece.

Without taking the feed rate v into account, there is only a stationary consideration of the impact pressure I, which is insufficient for regulating the descaling result.

Furthermore, determines the volume flow V _spec to: $${\dot{V}}_{\mathit{spec}}=\frac{\dot{V}}{b}$$

V̇_spez:

Spezifischer Volumenstrom pro m Breite des Werkstücks [l/s•m]

V̇:

Volumenstrom der ausgespritzen Flüssigkeit [l/s]

b:

Spritzbreite quer zur Bewegungsrichtung X [m]

Here mean:

V̇ _spec :

Specific volume flow per m width of the workpiece [l / s • m]

V̇:

Volume flow of the ejected liquid [l / s]

b:

Spray width across the direction of movement X [m]

The invention now works as follows:
For a desired descaling of the surfaces 20 of the workpiece 12, it is moved in the direction of movement X relative to the device 10 according to the invention. Here, the liquid 18 is sprayed from the jet nozzles 16 under high pressure onto the surfaces 20 of the workpiece 12, namely both on its upper side and on its lower side.

With reference to the above-mentioned equations and the relationships explained thereon, the specific energy input E can be increased, for example, by increasing the pressure with which the liquid is supplied to the jet nozzles and / or the volume flow V, and / or by increasing the distance A of the jet nozzles to the surface 20 of the workpiece 12 and / or the feed speed v are reduced, and / or by connecting a further jet nozzle arrangement. The opposite applies mutatis mutandis: A reduction in the specific energy input E is achieved by the pressure at which the liquid is supplied to the jet nozzles and / or the volume flow V is reduced, and / or by increasing the distance A of the jet nozzles to the surface 20 of the workpiece and / or the feed speed v, and / or by adding another Jet nozzle arrangement is switched off.

According to the present invention, an increase in the specific energy input E takes place e.g. in the event that it is determined on the basis of the signals from the surface inspection device 26 by means of the control device 22 that the surface quality of the workpiece 12 falls below a predetermined target value. Conversely, this means that the specific energy input E is reduced as long as the surface quality of the workpiece 12 maintains a predetermined target value.

In particular in the case of primary descaling of the workpiece 12, it may be advisable to set the specific energy input E, as explained on the basis of the signals from the surface inspection device 26, preferably solely by changing the feed rate v.

Fig. 5 shows a flowchart to illustrate an operating mode of the device 10 according to the invention or an implementation of a method according to the invention.

While the workpiece 12 moves past the device 10 in the direction of movement X and is descaled in the process, the descaling quality is continuously monitored by means of the surface inspection device 26. This allows local and immediately adjacent to a jet nozzle arrangement, for. B. in the form of a pair of rotor modules or a spray bar 38, it can be determined whether the desired surface quality for the workpiece 12 reaches a predetermined target value. If this is not the case, suitable control of the high-pressure pump unit 24 or of the / the frequency controller / s 25 provided for this purpose, the pressure with which the liquid 18 is supplied to the jet nozzles 16 can be increased by means of the control device 22, with a further pump of the high-pressure pump unit 24 possibly also being switched on.

In addition or as an alternative to the adjustment of the pressure already mentioned, it is also possible to switch on an additional jet nozzle arrangement. In the embodiment according to Fig. 3 this is the jet nozzle arrangement 14.2, for example in the form of a pair of rotor modules or a spray bar pair 38, which is provided downstream of the jet nozzle arrangement 14.1. This means that if the desired surface quality for the workpiece 12 is maintained - according to a normal operation of the present invention - only a single jet nozzle arrangement is used. Only in the event that the surface quality for the workpiece 12 should fall below the predetermined target value, then - in accordance with a special operation of the present invention - a second jet nozzle arrangement (cf. 14.2 in Fig. 3 ), whereby liquid 18 is then also sprayed under high pressure onto the surfaces 20 of the workpiece from the jet nozzles 16 of this second jet nozzle arrangement. The fact that only a single jet nozzle arrangement is used in normal operation of the invention contributes to the saving of energy for the production of high-pressure water.

According to the flowchart of Fig. 5 The operating parameters of the device 10 can also be adapted: by suitably actuating the high-pressure pump unit 24 by means of the control device 22, the pressure at which the liquid 18 is supplied to the jet nozzles 16 can be reduced until a recognizable residual scale falls below a minimal impact displays and then this pressure must be increased slightly again. The pressure for the jet nozzles 16 supplied liquid 18 is set to a sufficiently large value with which the surface quality reaches the predetermined target value.

In addition and / or alternatively, the impact pressure or the descaling pressure can be changed by adjusting the height of a jet nozzle arrangement. This height adjustment is in the Fig. 1 and in the Fig. 2 each symbolized by the arrow "H", and is achieved by the control device 22 suitably actuating the actuator of the height-adjustable holder H to which the jet nozzle arrangement is attached.

In addition and / or alternatively, the feed speed v of the workpiece 12 can be adapted to change the specific energy input E.

Finally, it is pointed out that the flow chart according to Fig. 5 illustrates a control loop in order to determine or set the desired specific energy input E with which the workpiece 12 is descaled. In this case, the abovementioned options are carried out or applied until the surface quality for the workpiece reaches a predetermined target value (in Fig. 5 referred to as the "target result").

Reference list

10th

contraption

12th

workpiece

14

Jet nozzle arrangement

14.1

Jet nozzle arrangement

14.2

Jet nozzle arrangement

16

Jet nozzles

18th

liquid

20

surface

22

Control device

23.1

Signal technology

23.2

Signal technology

23.3

Signal technology

April 23

Signal technology

24th

High pressure pump unit

25th

Frequency controller

26

Surface inspection device

28

Jet nozzle arrangement

36

Jet nozzle arrangement

38

Jet nozzle arrangement

40

Surface scanning unit

A

distance

H

height-adjustable bracket

v

Feed rate

X

Direction of movement

Claims (15)

1. Device (10) for descaling a workpiece (12), preferably hot-rolled material, moved relative to the device (10) in a movement direction, comprising at least one first jet nozzle arrangement (14; 28; 36; 38) with a plurality of jet nozzles (16), from which a liquid (18), particularly water, can be issued under high pressure onto a surface (20) of the workpiece (12),
   a control device (22), and
   a surface inspection device (26), which is in signal connection (23.2) with the control device (22) and which is arranged downstream from the jet nozzle arrangement (14; 28; 36; 38) with respect to the movement direction (X) of the workpiece (12), wherein scale on the surface (20) of the workpiece (12) is detectable by means of the surface inspection device (26) and wherein the surface inspection device is arranged directly adjacent to the jet nozzle arrangement,
   characterised in that
   the control device (22) has such a program configuration that the specific energy intake by which a surface (22) of the workpiece is acted on by the liquid (18) issued from the jet nozzles (16) can be regulated by means of the control device (22) in dependence on the signals of the surface inspection device (26) and
   the control device (22) has such a program configuration that on the basis of the signals of the surface inspection device (26) a surface quality for the workpiece (12) is determined and compared with a predetermined target value,
   wherein regulation of the specific energy intake is carried out in such a way that it is increased if the surface quality of the workpiece falls below the predetermined target value and is decreased if the surface quality of the workpiece exceeds the predetermined target value.
2. Device (10) according to claim 1, characterised in that a high-pressure pump unit (24), which is in signal connection (23.1) with the control device (22) and which is fluid connection with the jet nozzles (16) of the jet nozzle arrangement (14; 28; 36; 38), is provided, wherein the high-pressure pump unit (24) can be regulated by means of the control device (22) so that the pressure at which the liquid (18) is fed to the jet nozzles (16) is variable, preferably that the pressure for the liquid (18) fed to the jet nozzles (16) is correspondingly decreased or increased if the surface quality of the workpiece (12) exceeds or falls below the predetermined target value.
3. Device (10) according to claim 2, characterised in that the high-pressure pump unit (24) is equipped with a frequency regulator (25), wherein the high-pressure pump unit (24) is activated in dependence on the signals of the surface inspection device (26) so as to correspondingly decrease or increase the pressure for the liquid (18) fed to the jet nozzles (16).
4. Device (10) according to any one of the preceding claims, characterised in that a spacing (A) of the jet nozzle arrangement (14; 28; 36; 38) from the surface (20) of the workpiece (12) is variable, wherein this spacing (A) is settable by means of the control device (22) in controlled, preferably regulated, manner.
5. Device (10) according to any one of the preceding claims, characterised in that a rate (v) of advance of the workpiece (12) is settable by means of the control device (22) in regulated manner.
6. Device (10) according to any one of the preceding claims, characterised in that the surface inspection device (26) is so arranged that a three-dimensional measurement of a surface (20) of the workpiece (12) is carried out by that and a height profile of the surface (20) of the workpiece (12) is derived therefrom.
7. Device (10) according to any one of the preceding claims, characterised in that a second jet nozzle arrangement (14.2) with a plurality of jet nozzles (16), which are arranged adjacent to the first jet nozzle arrangement (14.1) and upstream or downstream thereof with respect to a movement direction (X) of the workpiece and which are in signal connection with the control device (22), is provided, wherein if the surface quality of the workpiece (12) falls below the predetermined target value the second jet nozzle arrangement (14.2) can be switched on in addition to the first jet nozzle arrangement (14.1) and then liquid (18) can be issued from the jet nozzles (16) of the switched-on second jet nozzle arrangement (14.2) under high pressure onto a surface (20) of the workpiece (12).
8. Device (10) according to any one of the preceding claims, characterised in that a surface scanning unit (40), which is in signal connection (23.3) with the control device (22) and which is arranged upstream of the jet nozzle arrangement (14; 28; 36; 38) with respect to the movement direction (X) of the workpiece (12), is provided, wherein the control device (22) is in signal connection with a setting drive of a height-adjustable mount (H) of the jet nozzle arrangement (14; 28; 36; 38) in such a way that if an irregularity at a surface (20) of the workpiece (12) is ascertained by means of the surface scanning unit (40) the control device (22) activates the setting drive of the height-adjustable mount (H) so that the spacing (A) of the jet nozzle arrangement (14; 28; 36; 38) with respect to the workpiece (12) can be increased.
9. Method for descaling a workpiece (12), preferably a hot-rolled material, which is moved relative to a first jet nozzle arrangement (14; 28; 36; 38), which comprises a plurality of jet nozzles (16), in a movement direction (X), wherein for descaling the workpiece (12) a liquid (18), particularly water, is sprayed from the jet nozzles (16) at high pressure onto a surface (20) of the workpiece (12), wherein a control device (22) is in respective signal connection (23.1; 23.2; 23.3; 23.4) with the jet nozzle arrangement (14; 28; 36; 38) and with a surface inspection device (26), wherein a surface (20) of the workpiece (12) is checked, by means of the surface inspection device (26), downstream of the jet nozzle arrangement (14; 28; 36; 38) with respect to the movement direction (X) of the workpiece (12), wherein a surface of the workpiece directly adjacent to the jet nozzle arrangement is checked by means of the surface inspection device,
   characterised in that
   the specific energy intake by which a surface (20) of the workpiece is acted on by the liquid (18) issued from the jet nozzles (16) is regulated by means of the control device (22) in dependence on the signals of the surface inspection device (26), and
   on the basis of the signals of the surface inspection device (26) a surface quality for the workpiece (12) is determined and compared with a predetermined target value,
   wherein the specific energy intake is regulated in such a way that it is increased if the surface quality of the workpiece falls below the predetermined target value and that it is decreased if the surface quality of the workpiece exceeds the predetermined target value.
10. Method according to claim 9, characterised in that a high-pressure pump unit (24) is regulated by means of the control device (22) so as to vary the pressure at which the liquid (18) is fed to the jet nozzles (16).
11. Method according to claim 10, characterised in that the pressure for the liquid (18) fed to the jet nozzles (16) is increased if the surface quality of the workpiece (12) falls below the predetermined target value or the pressure for the liquid fed to the jet nozzles (16) is reduced as long as the surface quality of the workpiece (12) adheres to the predetermined target value.
12. Method according to any one of claims 9 to 11, characterised in that a spacing (A) which the jet nozzle arrangement (14; 28; 36; 38) has from a surface (20) of the workpiece (12) is varied by means of the control device (22) in regulated manner, wherein the spacing (A) of the jet nozzle arrangement (14; 28; 36; 38) from the surface of the workpiece (12) is decreased if the surface quality of the workpiece (12) falls below the predetermined target value or wherein the spacing (A) of the jet nozzle arrangement (14; 28; 36; 38) from the surface (20) of the workpiece (12) is increased as long as the surface quality of the workpiece (12) adheres to the predetermined target value.
13. Method according to any one of claims 9 to 12, characterised in that a rate (v) of advance of the workpiece (12) in its movement direction (X) is decreased if the surface quality of the workpiece (12) falls below the predetermined target value or a rate (v) of advance of the workpiece in its movement direction (X) is increased as long as the surface quality of the workpiece (12) adheres to the predetermined target value.
14. Method according to any one of claims 9 to 13, characterised in that the surface inspection device (26) is arranged downstream of the jet nozzle arrangement (14; 28; 36; 38) with respect to the movement direction (X) of the workpiece (12) and directly adjacent to the arrangement.
15. Method according to any one of claims 9 to 14, characterised in that a second jet nozzle arrangement (14.2), which is arranged adjacent to the first jet nozzle arrangement (14.1) and upstream or downstream thereof with respect to a movement direction (X) of the workpiece and which is in signal connection with the control device (22), is provided, wherein if the surface quality of the workpiece (12) falls below the predetermined target value the second jet nozzle arrangement (14.2) is switched on in addition to the first jet nozzle arrangement (14.1) and then liquid (18) is sprayed from the jet nozzles (16) of the switched-on second jet nozzle arrangement (14.2) under high pressure onto a surface (20) of the workpiece (12).

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