EP3429773B1 - Device and method for descaling a moving workpiece - Google Patents

Description

The invention relates to a device and a method for descaling a workpiece that is moved relative to the device in one direction of movement. The workpiece is in particular a hot rolled product.

It is known in the prior art to spray water onto the surfaces of the workpiece at high pressure for descaling workpieces, in particular hot rolled material. To ensure that the surfaces of the workpiece are descaled without gaps, the high-pressure spray water is usually sprayed out of several nozzles of 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 rolling stock.

Out WO 2005/082555 A1 a scale washer is known, with which a rolling stock which is moved relative to the scale washer is descaled by irradiation with high-pressure spray water. This scale washer comprises at least one row of nozzle heads with a plurality of nozzle heads that span the width of the rolling stock, with each nozzle head being driven in rotation by a motor about an axis of rotation perpendicular to the rolling stock surface. Furthermore, at least two nozzles which are arranged eccentrically with respect to the axis of rotation are provided in each nozzle head and are arranged on the circumference of the nozzle head as close as possible in terms of construction. Such a scale washer is subject to the disadvantage that an energy input across the width of the rolling stock can have inhomogeneities, so that permanent temperature streaks can occur. Furthermore, the nozzles on the respective nozzle heads are arranged inclined outwards by an angle of attack. As a result, the direction of spraying of these nozzles is also aligned in the direction of the feed of the rolling stock when the nozzle heads are rotated about their axis of rotation. Such an alignment of the high-pressure spray water discharged from the nozzles is disadvantageous in that the jet of the spray water is ineffective and therefore makes no contribution to descaling the surface of the rolling stock.

Out WO 1997/27955 A1 A method for descaling rolling stock is known, in which a rotor descaling device is provided, by means of which a liquid jet is sprayed onto a surface of the rolling stock to be descaled. To ensure only a slight cooling of the rolling stock and to generate high jet pressures with a low operating fluid pressure, the liquid jet is formed intermittently, that is to say temporarily. Due to the interruption of the liquid jet one or more times, pressure peaks occur, which have the effect of increasing the jet pressure, thereby improving the descaling effect for the rolling stock. However, a control disk provided for this purpose, which is provided in fluid connection with a pressure medium supply line, disadvantageously increases the design effort for this descaling technique. Furthermore, there is a risk in the formation of the pressure peaks that this leads to increased material stress, in particular due to cavitation.

Out DE 10 2014 109 160 A1 a device and a method for descaling a workpiece are known which are moved relative to the device in a direction of movement. For this purpose, several blasting nozzles are provided on a rotating rotor head in the form of a nozzle holder, liquid being sprayed or sprayed under high pressure from the blasting nozzles onto a surface of the rolling stock in such a way that the direction of radiation with which the liquid is sprayed out of the blasting nozzles always runs at an angle to the direction of movement of the rolling stock. This oblique alignment of the direction of radiation ensures that removed scale is transported away from the surface of the rolling stock to the side away from the rolling stock. However, this is accompanied by a disadvantageous heavy contamination of the system or its surrounding area.

Out DE 43 02 331 A1 A generic device for descaling a workpiece according to the preamble of claim 1 and a corresponding method according to the preamble of claim 6 are known.

The invention has for its object to optimize the descaling of a workpiece with simple means.

This object is achieved by a device having the features defined in claims 1 and 3, and by a method having the features defined in claims 6 and 8. Advantageous developments of the invention are defined in the dependent claims.

A device according to the present invention is used for descaling a workpiece, preferably a hot rolling stock, which is moved in a direction of movement relative to the device, and comprises at least one rotor head which can be rotated about an axis of rotation and to which a plurality of jet nozzles are attached, a liquid, in particular water, from the jet nozzles. can be applied to the workpiece at an angle of attack at an angle to the surface of the workpiece. Furthermore, the device comprises a control device, which is connected to drive means of the rotor head in terms of signals and is programmed in such a way that the speed at which the rotor head is rotated about its axis of rotation is adapted to a feed rate at which the workpiece is moved in its direction of movement can be. For this purpose, the control device preferably comprises a control loop in order to implement the aforementioned adaptation of the rotational speed of the rotor head to the feed speed of the workpiece. Mutatis mutandis, the feed speed of the workpiece can also be adapted to the speed of the rotor head.

Additionally and / or alternatively, it is provided for the device that the majority of the jet nozzles are attached to the rotor head at a different radial distance from its axis of rotation, with a larger volume flow of liquid from a jet nozzle which has a greater radial distance from the axis of rotation can be applied than in comparison to a jet nozzle that has a smaller radial distance from the axis of rotation.

In the same way, the invention also provides a method for descaling a workpiece, preferably a hot rolled product. Here, the workpiece is moved relative to a device in one direction of movement, this device having at least one rotor head rotatable about an axis of rotation, to which a plurality of jet nozzles are attached. While the rotor head is rotated about its axis of rotation, a liquid, in particular water, is applied or sprayed from the jet nozzles onto the workpiece at an angle of incidence at an angle to the surface of the workpiece. It is provided for the method that the speed at which the at least one rotor head is rotated about its axis of rotation is adapted by means of a control device to a feed rate at which the workpiece is moved in its direction of movement. This adaptation of the speed of the rotor head to the feed speed of the workpiece is preferably regulated, i.e. by using an appropriate control loop with which the control device is equipped. As already mentioned above for the device, the feed speed of the workpiece can also be adapted mutatis mutandis to the speed of the rotor head.

Additionally or alternatively, it is provided for the method that volume flows of liquid of different sizes are sprayed out of a plurality of jet nozzles, which are each attached to the rotor head at a different radial distance from its axis of rotation, with one jet nozzle having a larger radial one Has a distance from the axis of rotation, a larger volume flow of liquid is injected than in comparison to a jet nozzle, which has a smaller radial distance from the axis of rotation.

The invention is based on the essential finding that an optimization and homogenization of the specific energy input on the surface of the Workpiece, namely through the liquid sprayed thereon under high pressure, along, ie in the direction of movement of the workpiece, by adapting the speed of the rotor head to the feed speed of the workpiece.

A further optimization of the specific energy input is achieved for the liquid sprayed at high pressure onto the surface of the workpiece in that a plurality of jet nozzles are attached to the rotor head at a different radial distance from its axis of rotation, with one jet nozzle having a larger one has a radial distance from the axis of rotation, then a larger volume flow of liquid is applied than in comparison to a jet nozzle, which has a smaller radial distance from the axis of rotation. This can be achieved in a simple manner by selecting a suitable type of nozzle, so that from a jet nozzle which is arranged radially further away from the axis of rotation of the rotor head, a correspondingly larger amount of liquid, i.e. a larger volume flow is sprayed out. Such a configuration of a plurality of jet nozzles on the rotor head accordingly reduces the energy input for the liquid transversely to the direction of movement of the workpiece, ie. H. across its width, optimized.

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, ie 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 depends on the pressure at 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 with which the workpiece is moved in its direction of movement. A change the specific energy input, depending on the signals of the surface inspection device, can be made by adapting the parameters mentioned above, namely by means of the control device, as will be explained in detail below.

In an advantageous development of the method according to the invention, an arrangement of rotor heads and a jet nozzle arrangement can be provided, which are arranged one behind the other and in particular adjacent to one another with respect to the direction of movement of the workpiece. In the case of an arrangement of rotor heads, also referred to here as a rotor head arrangement, the present invention is either a pair of rotor heads in which a rotor head is provided above and below a workpiece, ie on the top and bottom thereof, or a pair of rotor modules in which - above and below the workpiece - a plurality of rotor heads are combined side by side and transverse to the direction of movement of the workpiece. In normal operation it can be provided that liquid is sprayed onto the workpiece only from the jet nozzles of the rotor head arrangement. In a special operation, the jet nozzles of the jet nozzle arrangement can then be switched on, so that liquid is also applied or sprayed onto the workpiece from the jet nozzles of this jet nozzle arrangement. In this case, the blasting nozzles of both the rotor head arrangement and the blasting nozzle arrangement are used for descaling the workpiece. The use of both the rotor head arrangement and the jet nozzle arrangement in special operation is recommended e.g. B. for difficult to descaling steel grades, or for stubborn scale residues, which can arise, for example, from contact surfaces on oven rolls. In such an embodiment, according to which only the jet nozzles of the rotor head arrangement are used in normal operation, the operating consumption can advantageously be minimized.

This applies in the same way to the case where a plurality of rotor heads - as explained - are combined to form a rotor head module. This is because only one pair of rotor modules is in use during normal operation, with a further pair of jet nozzles that move in the direction of movement of the workpiece e.g. is arranged downstream, is switched on if necessary. This applies in the same way in the event that the rotor head arrangement and the jet nozzle arrangement differ structurally, e.g. in that the jet nozzle arrangement is designed as a spray bar.

In an advantageous development of the invention, a surface inspection device connected to the control device for signaling purposes can be provided, which is arranged downstream of the rotor head in relation to the direction of movement of the workpiece and close to it in order to be able to detect any remaining scale on the surface of the workpiece. On the basis of the signals from this surface inspection device, the descaling quality of the workpiece is compared with a predetermined target specification by means of the control device and then, depending on this, a high-pressure pump unit, which is in fluid communication with the jet nozzles of the rotor head, is appropriately controlled or regulated. A high-pressure pump unit, which is in fluid communication with the jet nozzles of the rotor head, can be controlled in such a way that a pressure with which liquid is sprayed out of the jet nozzles onto the surface of the workpiece is set as a function of the signals from the surface inspection device. This means that the pressure for the liquid to be sprayed out is set just high enough to achieve an adequate descaling quality for the workpiece. If - as seen in the direction of movement of the workpiece - at least two jet nozzle arrangements are arranged one behind the other, it can be achieved by said control that a switchable jet nozzle arrangement is switched on appropriately depending on the signals of the surface inspection device, which corresponds to the special operation mentioned according to the invention . In comparison to a conventional two-row arrangement of rotor heads or spray bars, such a single-row arrangement ie a single rotor head or jet nozzle arrangement, which is used in normal operation, achieves a substantial saving in operating media.

By the above adjustment of pressure, i. H. By reducing the pressure, there is also a reduced abrasion effect of the liquid on all surrounding materials or system parts, as a result of which both the maintenance costs decrease and wear on the jet nozzles themselves is reduced.

By installing a surface inspection device and integrating it into a control or regulating device, the amount of water required for a clean descaling of the workpiece can be suitably minimized by varying the pressure and / or the volume flow. This leads to a saving in energy for the provision of high-pressure water, and in the same way to a reduced cooling of the workpiece as a result of a reduced amount of liquid which is sprayed onto the workpiece.

In addition, it should be pointed out that the distance between the rotor head and the surface of the workpiece can be adjusted. This allows adaptation to different batches of workpieces with different heights. In addition, it is also possible to set this distance between the rotor head and the surface of the workpiece as a function of the signals from the surface inspection device. For example, it can be provided in this way that, if the descaling quality is insufficient, the distance between the rotor head and the surface of the workpiece is reduced, so that this results in a greater impact pressure on the surface of the workpiece with respect to the liquid sprayed thereon. This also applies mutatis mutandis the other way round, according to which the distance between the rotor head and the surface of the workpiece can be increased at least slightly if the descaling quality exceeds the predetermined target value.

In an advantageous development of the invention, the pressure at which the liquid is applied to a rotor head arrangement which is arranged below the workpiece can be selected to be greater than that for a rotor head arrangement which is arranged above the workpiece. This makes it possible that even stubborn scale from the underside of the workpiece, e.g. formed as a result of contact with guide rollers, is reliably removed. Correspondingly, scale-free, clean surfaces with comparatively low water consumption are achieved for a workpiece, which saves a considerable amount of energy for generating the high-pressure water.

Due to the reduced specific amount of water used for descaling the workpiece, the heating energy required for an oven and / or for induction heating, or the forming energy required for subsequent rolling of the workpiece can be considerably reduced. Due to the temperature saving, thinner final thicknesses can be generated for a workpiece or a hot rolled product, so that the product mix can be enlarged. In addition, the lifespan of oven rollers increases considerably at a lower oven temperature.

• Fig. 1 eine prinzipiell vereinfachte Seitenansicht einer erfindungsgemäßen Vorrichtung,
• Fig. 2 eine prinzipiell vereinfachte Draufsicht auf eine erfindungsgemäße Vorrichtung nach einer weiteren Ausführungsform,
• Fig. 3a,
• Fig. 3b,
• Fig. 3c jeweils einen prinzipiellen Zusammenhang zwischen einer Spritzrichtung von Strahldüsen einer Vorrichtung von Fig. 1 bzw. Fig. 2, und einer Bewegungsrichtung, in der ein Werkstück an dieser Vorrichtung vorbeibewegt wird,
• Fig. 4 eine vereinfachte Frontalansicht eines Rotormodul-Paars, das Teil einer Vorrichtung gemäß Fig. 2 sein kann,
• Fig. 5 eine mögliche Anordnung von Strahldüsen von einem Rotorkopf, zur Verwendung bei einer Vorrichtung gemäß Fig. 1 oder Fig. 2,
• Fig. 6 ein Ablaufdiagramm zur Ausführung der vorliegenden Erfindung, und
• Fig. 7a,
• Fig. 7b jeweils Spritzbilder, die sich mit einer auf ein Werkstück ausgespritzten Flüssigkeit auf der Oberfläche des Werkstücks ausbilden,

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

• Fig. 1 a principally simplified side view of a device according to the invention,
• Fig. 2 a basically simplified top view of a device according to the invention according to a further embodiment,
• Fig. 3a ,
• Fig. 3b ,
• Fig. 3c each have a basic relationship between a spray direction of jet nozzles of a device from Fig. 1 respectively. Fig. 2 , and one Direction of movement in which a workpiece is moved past this device
• Fig. 4 a simplified frontal view of a pair of rotor modules, the part of a device according to Fig. 2 can be,
• Fig. 5 a possible arrangement of jet nozzles from a rotor head, for use in a device according to Fig. 1 or Fig. 2 ,
• Fig. 6 a flowchart for carrying out the present invention, and
• Fig. 7a ,
• Fig. 7b in each case spray patterns which form on the surface of the workpiece with a liquid sprayed onto a workpiece,

Below, with reference to the Figures 1 to 6 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. In some figures, Cartesian coordinate systems are entered 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 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 is made up of a rotor head 14 ( Fig. 1 ) educated. Rotation of the rotor head 14 about its axis of rotation R is carried out by drive means which in Fig. 1 symbolically by an "M" are designated and can be formed, for example, from an electric motor. Blasting nozzles 16 are attached to an end face of the rotor head 14 which faces the workpiece 12. A liquid 18 (in Fig. 1 simply symbolized with dashed lines) sprayed under high pressure onto a surface 20 of the workpiece 12 in order to descale the workpiece 12 in a suitable manner.

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. Correspondingly, the spray direction S, in which the liquid is sprayed from the jet nozzles 16, also runs parallel to the axis of rotation R of the rotor head. The axis of rotation R is arranged inclined at an angle γ with respect to an orthogonal to the surface 20 of the workpiece. This results in an angle of attack α for the jet nozzles 16, with which the liquid 18 sprayed from the jet nozzles 16 hits the surface 20 of the workpiece 12. Because of the parallelism of the longitudinal axes L to the axis of rotation R, in the example shown the angle of attack a is equal to the angle of inclination γ of the axis of rotation R, the angle of attack a remaining constant during a rotation of the rotor head 14 about its axis of rotation R. This embodiment supports the function of the invention in a particularly advantageous manner, but other designs of rotor head jet nozzle arrangements can also be used.

The rotor head 14 is designed to be height-adjustable, for example by attachment to a height-adjustable holder, which in the Fig. 1 simplified symbolized by the double arrow "H". The holder H can have an actuator (not shown in the drawing). Thus, a distance A, which an intersection of the axis of rotation R has with the end face of the rotor head 14 to the surface 20 of the workpiece 12, can 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.

The device 10 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 such 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. The liquid 18, which is then sprayed under high pressure from the jet nozzles 16 onto the workpiece 12, is preferably water, without any restriction being limited to the medium water.

At least one pump of the high-pressure pump unit 24 is equipped with a frequency controller 25. This makes it possible to control the high-pressure pump unit 24 as continuously as possible by means of the control device 22 in order to be able to change the pressure with 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 explained 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 an 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 connected to the control device 22 in terms of signal technology. Thus, by means of the surface inspection device 26 and a corresponding one Evaluation in the control device 22 scale or residual scale can be detected on the surface 20 of the workpiece 12. Thus, the surface inspection device 26 corresponds to a scale detection device. 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 drive means M of the rotor head 14 are connected to the control device 22 in terms of signals. This makes it possible to set the speed of rotation of the rotor head 14 about its axis of rotation 14. In the same way, means (not shown) with which the feed speed v of the workpiece 12 can be set or changed, and the height-adjustable holder H are each signal-technically connected to the control device 22, as will be explained in detail below.

Fig. 2 shows a further embodiment of the device 10 according to the invention, namely in a simplified plan view. In this embodiment, an arrangement 14.1 of rotor heads and a jet nozzle arrangement 14.2 are arranged one behind the other with respect to the direction of movement X of the workpiece 12. The jet nozzle arrangement 14.2 can be designed in the form of an arrangement of rotor heads, these arrangements 14.1, 14.2 of rotor heads being referred to as “rotor head arrangements” for short. The rotor heads of the two rotor head arrangements 14.1 and 14.2 are each connected to the high-pressure pump unit 24, as with reference to FIG Fig. 1 explained. In the embodiment of Fig. 2 the surface inspection device 26 is positioned downstream of the rotor head arrangement 14.2. For clarification, it should be pointed out that in the presentation of Fig. 2 a width of the workpiece 12 extends in the direction y, the axes of rotation R for the rotor head arrangements 14.1 and 14.2 each running perpendicular to the plane of the drawing. Other embodiments, for example as a spray bar, can also be used for the jet nozzle arrangement 14.2 positioned downstream.

The signaling connections between on the one hand the control device 22 and on the other hand individual components of the device 10 are shown in Fig. 1 and Fig. 2 each symbolically indicated by dotted lines. In detail: The signal connection between the control device 22 and the high-pressure pump unit 24 is designated by the reference symbol 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 signal connection between the control device 22 and drive means M of the rotor head 14 is designated by the reference symbol 23.3. The signal connection between the control device 22 and the height adjustment H is designated by the reference symbol 23.4. 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 designated by the reference symbol 23.5. These connections 23.1-23.5 can either be physical lines or a suitable radio link or the like.

The Fig. 3 illustrates a relationship between the spray direction S, with which the liquid 18 is sprayed out of the jet nozzles 16, and the direction of movement X, with which the workpiece 12 is moved past the device 10 or its rotor head 14. This is clarified in detail Fig. 3 a projection of the spray direction S into a plane parallel to the surface 20 of the workpiece 12. In the example according to 3a, 3b and 3c The spray direction S, with which the liquid 18 is discharged from a nozzle mouth 17 of a jet nozzle 16, is oriented in the opposite direction to the movement direction X, ie at a spray angle β of approximately 170 ° -190 ° to the movement direction X. This leads to the fact that the spray direction S of the liquid 18, when it is permanently sprayed onto the workpiece 12 under high pressure, has no portion or only a slight portion which points in the direction of a lateral edge of the workpiece 12. This mode of operation particularly expediently supports the effect of the invention.

A particularly good effect of the invention results from the fact that the above-described orientation of the spray direction S, as shown in the diagrams 3a, 3b and 3c , remains unchanged or constant during a rotation of the rotor head 14 about its axis of rotation R. The same applies to the angle of attack a.

Below is with reference to the Fig. 4 a possible arrangement of rotor heads 14 shown and explained, which in the embodiment of FIG Fig. 2 can be used.

Fig. 4 shows a frontal view of rotor modules, wherein a rotor module 30.1 is provided above and a rotor module 30.2 below the workpiece 12, thereby forming a pair of rotor modules 32. Specifically, the rotor modules 30.1 and 30.2 each consist of a plurality of rotor heads 14 which are arranged side by side and transversely (ie in the Fig. 4 in the direction of the y-axis) to the direction of movement X of the workpiece. For a uniform specific energy input, the distance between the individual rotors must be determined in such a way that the spray marks of the outer jet nozzles overlap in the spray pattern; however, the jet of two such nozzles does not strike the same point on the workpiece at the same time. Deviating from the representation in the Fig. 4 fewer or more than three rotor heads 14 can also be combined to form a rotor module 30.1, 30.2.

With regard to the embodiment according to Fig. 4 it is pointed out that the individual rotor heads 14 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 attached to the rotor heads 14 are supplied with high-pressure water.

Fig. 5 symbolizes an attachment of several jet nozzles 16 on a lower end face of a rotor head 14. In the example of Fig. 5 three jet nozzles 16.1, 16.2 and 16.3 are provided, each having a different distance s from the axis of rotation R of the rotor head 14. When representing Fig. 5 The axis of rotation R runs perpendicular to the plane of the drawing.

The different distances between the respective jet nozzles 16.1, 16.2 and 16.3 are shown in Fig. 5 each designated S ₁ , S ₂ , and S ₃ , with the proviso: S ₁ > S ₂ > S ₃ . With such an arrangement of jet nozzles, each with a different radial distance from the axis of rotation R, it is provided that a larger volume flow of liquid is sprayed out of a jet nozzle which has a greater radial distance from the axis of rotation R than in comparison to a jet nozzle which has a smaller distance to the axis of rotation. With respect to the three nozzles 16.1, 16.2 and 16.3 according to Fig. 5 the relationship then applies to the volume flow discharged from these nozzles: V̇ ₁ > V̇ ₂ > V̇ ₃ . Here, the volume flow V̇ _{1 is} discharged from the jet nozzle 16.1, the volume flow V̇ ₂ from the jet nozzle 16.2, and the volume flow V̇ ₃ from the jet nozzle 16.3. As a result, a uniform energy input is achieved on the surface 20 of the workpiece 12 transverse to its direction of movement X for the liquid discharged from the jet nozzles 16.1, 16.2 and 16.3.

The just in relation to the representation of Fig. 5 The relationships explained also apply to a number of jet nozzles of greater or less than three, namely in any case for a plurality of jet nozzles, each of which is at a different distance from the axis of rotation R of the rotor head 14. It should also be noted that the example of Fig. 5 also applies to all rotor heads 14 which in the Fig. 1-4 are shown and explained.

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]

V:

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]

V:

Volume flow of the sprayed liquid [l / s]

b:

Spray width transverse to 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. In this case, 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.

Fig. 6 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. As a result, it can be ascertained close to the location and / or immediately adjacent to a jet nozzle arrangement whether the desired surface quality for the workpiece 12 reaches a predetermined desired value. If this is not the case, various actuators are available for adaptation in order to achieve the desired surface quality with the lowest possible specific energy input or, if the quality is achieved, the specific one Reduce energy input successively in order to achieve an acceptable quality at the lowest possible energy input.

Correspondingly, the pressure with which the liquid 18 is supplied to the jet nozzles 16 can be increased by a suitable control of the high-pressure pump unit 24 or of the frequency controller (s) 25 provided for this purpose by means of the control device 22, with a further pump of the high-pressure pump unit possibly also 24 is switched on.

In addition or as an alternative to the adjustment of the pressure already mentioned, it is also possible to switch an additional jet nozzle arrangement on or off. In the embodiment according to Fig. 2 this is the jet nozzle arrangement 14.2, for example in the form of a pair of rotor heads 28 or a pair of rotor modules 32, 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. 2 ), whereby liquid 18 is also sprayed under high pressure onto the surfaces 20 of the workpiece from the jet nozzles 16 of this second jet nozzle arrangement. As soon as it is no longer necessary, the connection of the second jet nozzle arrangement 14.2 is canceled again. The fact that only a single jet nozzle arrangement is used in normal operation of the invention makes a contribution to saving energy and high-pressure water.

According to the flow chart of Fig. 6 The operating parameters of the device 10 can also be adapted: by a suitable one Activation of the high-pressure pump unit 24 by means of the control device 22 can reduce the pressure with which the liquid 18 is supplied to the jet nozzles 16 until recognizable residual scale indicates that a minimum specific energy input has been undershot and then this pressure has to be increased again slightly. Here, the pressure for the liquid 18 supplied to the jet nozzles 16 is set to a sufficiently large value with which the surface quality reaches the predetermined desired value. In other words, the pressure with which the liquid 18 is supplied to the jet nozzles 16 is reduced as long as the surface or descaling quality of the workpiece 12 maintains a predetermined target value.

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

The flow chart according to Fig. 6 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 possibilities are carried out or applied until the surface quality for the workpiece reaches a predetermined target value (in Fig. 6 referred to as the "target result").

Means (not shown) are provided by which the control device 22 receives information regarding the current feed speed v of the workpiece 12 in its direction of movement X. The same applies in the event that the feed rate v has been adjusted or changed, which is then also signaled to the control device 22 by the means mentioned. Based on this, the control device 22 can be used to select a desired one Rotation speed for a rotor head 14 can be set, namely in adaptation to the feed rate of the workpiece 12. Such an adjustment is also possible in ongoing production operation if there are fluctuations in the feed rate v for the workpiece 12 or this feed rate as a necessary actuator for adjusting the Descaling quality is changed. In terms of programming, the control device 22 can be set up in such a way that the speed of rotation of a rotor head 14 is also adjusted in a controlled manner.

By means of the just-mentioned adaptation of the speed of rotation of the rotor head 14 to the feed speed v of the workpiece 12 in its direction of movement X, an optimal energy input is achieved for the liquid 18 sprayed onto the surface 20 of the workpiece 12, namely along the direction of movement X. Such an optimal adaptation of the The speed of rotation of the rotor head 14 at the feed speed v of the workpiece 12 is shown in the spray pattern Fig. 7a shown, which shows a section of a surface 20 of the workpiece 12 in a plan view. In contrast, the representation of Fig. 7b a non-optimal adaptation of the rotational speed of the rotor head 14 to the feed speed v of the workpiece 12. By means of the invention it is possible to produce a spray pattern according to the representation of Fig. 7b to avoid.

As previously related to Fig. 5 is explained by the fact that a larger volume flow V of liquid 18 is sprayed onto the workpiece 12 from the jet nozzles 16, which are at a greater radial distance with respect to the axis of rotation R, an optimization of the energy input transverse to the direction of movement X of the workpiece 12, ie in the y direction. Such a setting of differently large volume flows V for jet nozzles 16, each of which is at a different distance from the axis of rotation R, is ensured in the manufacture of the device 10 according to the invention by a suitable selection of different nozzle types.

In addition and / or alternatively, the feed speed v with which the workpiece is moved in its direction of movement X can also be controlled, preferably adjusted, for example as a function of the determined surface or descaling quality of the workpiece 12 and / or according to the control device 22 .

Reference list

10th

contraption

12th

workpiece

14

Rotor head

14.1

Rotor head arrangement

14.2

Rotor head arrangement

16

Jet nozzles

16.1

Jet nozzles

16.2

Jet nozzles

16.3

Jet nozzles

18th

liquid

20th

surface

22

Control device

24th

High pressure pump unit

26

Surface inspection device

29

Rotor head pair

32

Scale detection device

α

Angle of attack

β

Spray angle

M

Drive means

R

Axis of rotation

S

Spray direction

S ₁

distance

S ₂

distance

S ₃

distance

V ₁

Volume flow

V ₂

Volume flow

V ₃

Volume flow

v

Feed rate

X

Direction of movement

Claims (17)

1. Device (10) for descaling a workpiece (12), preferably hot-rolled material, moved in a movement direction (X) relative to the device (10), comprising
   at least one rotor head (14), which is rotatable about an axis (R) of rotation and on which a plurality of jet nozzles (16; 16.1, 16.2, 16.3) is mounted, wherein a liquid (18), particularly water, can be applied to the workpiece (12) at an angle (a) of incidence inclined with respect to an orthogonal to a surface (20) of the workpiece (12) and a control device (22),
   characterised in that
   the control device (22) is in signal connection with drive means (M) of the rotor head (14) and is so arranged in terms of program that the rotational speed at which the rotor head (14) is rotated about its axis (R) of rotation is adaptable to a rate of advance at which the workpiece (12) is moved in its direction of movement, preferably in that the control device (22) comprises a regulating circuit and thus the adaptation of the rotational speed of the rotor head (14) to the rate of advance of the workpiece (12) is carried out in regulated manner.
2. Device (10) according to claim 1, characterised in that the jet nozzles (16; 16.1, 16.2, 16.3) of the plurality are mounted on the rotor head (14) at different radial spacings (s₁; s₂; s₃) from the axis (R) of rotation thereof, wherein a larger volume flow (V₁; V̇₂; V̇₃) of liquid (18) can be applied from a jet nozzle (16; 16.1, 16.2, 16.3), which has a larger radial spacing from the axis (R) of rotation, than by comparison with a jet nozzle having a smaller radial spacing from the axis (R) of rotation.
3. Device (10) for descaling a workpiece (12), preferably hot-rolled material, moved in a movement direction (X) relative to the device (10), comprising
   at least one rotor head (14), which is rotatable about an axis (R) of rotation and on which a plurality of jet nozzles (16; 16.1, 16.2, 16.3) is mounted, wherein a liquid (18), particularly water, can be applied to the workpiece (12) at an angle (α) of incidence inclined with respect to an orthogonal to a surface (20) of the workpiece (12) and a control device (22),
   characterised in that
   the jet nozzles (16; 16.1, 16.2, 16.3) of the plurality are mounted on the rotor head (14) at different radial spacings (s₁; s₂; s₃) from the axis (R) of rotation thereof, wherein a larger volume flow (V̇₁; V̇₂; V̇₃) of liquid (18) can be applied from a jet nozzle (16; 16.1, 16.2, 16.3), which has a larger radial spacing from the axis (R) of rotation, than by comparison with a jet nozzle having a smaller radial spacing from the axis (R) of rotation.
4. Device (10) according to claim 3, characterised in that the control device (22) is in signal connection with drive means (M) of the rotor head (14) and is so arranged in terms of program that the rotational speed at which the rotor head (14) is rotated about its axis (R) of rotation is adaptable to a rate of advance at which the workpiece (12) is moved in its direction of movement, preferably in that the control device (22) comprises a regulating circuit and thus adaptation of the rotational speed of the rotor head (14) to the rate of advance of the workpiece (12) is carried out in 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 in controlled, preferably regulated, manner by means of the control device (22).
6. Method of descaling a workpiece (12), preferably a hot-rolled material, moved in a movement direction (X) relative to a device (10), with at least one rotor head (14), which is rotatable about an axis (R) of rotation and on which a plurality of jet nozzles (16; 16.1, 16.2, 16.3) is mounted, wherein a liquid (18), particularly water, is applied from the jet nozzles (16; 16.1, 16.2, 16.3) to the workpiece (12) at an angle (α) of incidence inclined relative to the surface (20) of the workpiece (12) while the rotor head (14) is rotated about its axis (R) of rotation,
   characterised in that
   the rotational speed at which the at least one rotor head (14) is rotated about its axis (R) of rotation is adapted by means of a control device (22) to a rate of advance at which the workpiece (12) is moved in its movement direction (X), preferably such that the adaptation of the rotational speed of the rotor head (14) to the rate of advance of the workpiece (12) takes place in regulated manner.
7. Method according to claim 6, characterised in that volume flows (V̇₁; V̇₂; V̇₃) of liquid (18) of different size are sprayed from a plurality of jet nozzles (16; 16.1, 16.2, 16.3) mounted on the rotor head (14) at respectively different radial spacings (s₁; s₂; s₃) from the axis (R) of rotation thereof, wherein a larger volume flow (V̇₁; V̇₂; V̇₃) of liquid (18) is sprayed from a jet nozzle (16; 16.1; 16.2; 16.3), which has a larger radial spacing from the axis (R) of rotation, than by comparison with a jet nozzle having a smaller radial spacing from the axis (R) of rotation.
8. Method of descaling a workpiece (12), preferably a hot-rolled material, moved in a movement direction (X) relative to a device (10), with at least one rotor head (14), which is rotatable about an axis (R) of rotation and on which a plurality of jet nozzles (16) is mounted, wherein a liquid (18), particularly water, is applied from jet nozzles (16) to the workpiece (12) at an angle (a) of incidence inclined relative to the surface (20) of the workpiece (12) while the rotor head (14) is rotated about its axis (R) of rotation, characterised in that
   volume flows (V̇₁; V̇₂; V̇₃) of liquid (18) of different size are sprayed from a plurality of jet nozzles (16; 16.1, 16.2, 16.3) mounted on the rotor head (14) at respectively different radial spacings (s₁; s₂; s₃) from the axis (R) of rotation thereof, wherein a larger volume flow (V̇₁; V̇₂; V̇₃) of liquid (18) is sprayed from a jet nozzle (16; 16.1; 16.2; 16.3), which has a larger radial spacing from the axis (R) of rotation, than by comparison with a jet nozzle having a smaller radial spacing from the axis (R) of rotation.
9. Method according to claim 8, characterised in that the rotational speed at which the at least one rotor head (14) is rotated about its axis (R) of rotation is adapted by means of a control device (22) to a rate of advance at which the workpiece (12) is moved in its movement direction (X), preferably such that the adaptation of the rotational speed of the rotor head (14) to the rate of advance of the workpiece (12) takes place in regulated manner.
10. Method according to any one of claims 6 to 9, characterised in that when the rotor head (14) is rotated about its axis (R) of rotation the spray direction (S) of the liquid (18) issued from the jet nozzles (16; 16.1, 16.2, 16.3) remains in constant opposition referred to a projection in a plane parallel to the surface (20) of the workpiece (12), i.e. remains oriented at a spray angle (β) between 170° and 190°, particularly at a spray angle (β) of exactly 180°, to the direction (X) of movement of the workpiece (12).
11. Method according to any one of claims 6 to 10, characterised in that a rotor head arrangement (14.1) and a jet nozzle arrangement (14.2) are provided which with respect to the direction (X) of movement of the workpiece (12) are arranged one after the other and, in particular, adjacent to one another, wherein in normal operation liquid (18) is applied to the workpiece (12) only from the jet nozzles (16) of the rotor head arrangement (14.1), wherein in a special operation the jet nozzles (16) of the jet nozzle arrangement (14.2) are switched on so that liquid (18) is also applied to the workpiece (12) from the jet nozzles (16) of the jet nozzle arrangement (14.2) and correspondingly for descaling of the workpiece (12) not only the rotor head arrangement (14.1), but also the jet nozzle arrangement (14.2) are then used.
12. Method according to any one of claims 6 to 11, characterised in that a surface inspection device (26) which is arranged downstream of the rotor head (14) with respect to the direction (X) of movement of the workpiece (12) and which is in signal connection with the control device (22) is provided, wherein scale remaining on the surface (20) of the workpiece (12) is detected by the surface inspection device (26) and wherein the control device (22) is so arranged in terms of program that on the basis of the signals of the surface inspection device (26) the quality of descaling of the workpiece (12) is compared with a predetermined target and in dependence thereon a high-pressure pump unit (24) in fluid connection with the jet nozzles (16; 16.1, 16.2, 16.3) of the rotor head (14) is controlled, preferably regulated.
13. Method according to claim 11 or 12, characterised in that the jet nozzles (16) of the jet nozzle arrangement (14.2), which can be switched on, is placed in operation, namely in the special operation, in dependence on the signals of a scale detection device (32).
14. Method according to claim 12 or 13, characterised in that a pressure at which the liquid (18) is sprayed from the jet nozzles (16; 16.1, 16.2, 16.3) is settable or set in dependence on the signals of the surface inspection device (26) by means of activation of the high-pressure pump unit (24).
15. Method according to any one of claims 12 to 14, characterised in that the spacing (A) of the rotor head from the surface (20) of the workpiece (12) is adjusted, namely in dependence on the signals of the surface inspection device (26).
16. Method according to any one of claims 12 to 15, characterised in that a rate (v) of advance of the workpiece (12) in its direction (X) of movement is reduced if the quality of descaling of the workpiece (12) falls below the predetermined target or a rate (v) of advance of the workpiece in its direction (X) of movement is increased as long as the quality of descaling of the workpiece (12) adheres to the predetermined target.
17. Method according to any one of claims 6 to 16, characterised by a rotor head pair (29) or a rotor module pair (31) in which at least one rotor head (14) is arranged respectively above and below the moved workpiece (12), wherein the pressure at which a liquid (18) is applied to the workpiece (12) by the jet nozzles (16; 16.1, 16.2, 16.3) of the rotor head arranged below the workpiece (12) is greater than in the case of the jet nozzles (16; 16.1, 16.2, 16.3) of the rotor head arranged above the workpiece (12).

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