EP2403663B1 - Method and cooling device for cooling the rollers of a roll stand - Google Patents

Description

The invention relates to methods and a cooling device for cooling the rollers, in particular the work rolls of a roll stand, see, for example JP-A 63303609 ,

When rolling metals, the rollers involved in the rolling process, the work rolls, are heated. To protect them from damage and to obtain as long as possible, the rollers are cooled. Cooling systems are nowadays used in most rolling mills, which spray a cooling liquid onto the roll surface with the aid of nozzles (preferably flat-jet nozzles). Such cooling is referred to as spray cooling. Depending on the rolling mill, the selected pressure level is between 6 bar and 12 bar and, in exceptional cases, 20 bar. In addition to the task of cooling the work rolls as intensively as possible in order to limit their thermal stress and geometric expansion, the work roll cooling should keep the roll free of dirt, oxide and scale particles. The cooling effect increases with higher coolant quantity and increasing coolant pressure. Disadvantage of the system is that it requires a large amount of energy and at higher pressure, the maintenance of the pump is more complex.

Another way to cool the work rolls is the low pressure cooling. From the WO 2008/104037 A1 is a cooling device with highly turbulent cooling in the low pressure region is known in which by means of nozzles or bores, which are arranged on a concave shaped cooling beam, a roller is cooled. The arrangement of the cooling bar and with the help of side plates, which are mounted on the front side of the cooling beam, a uniformly formed water cushion is formed with a turbulent and non-directional flow. However, the cooling device works satisfactorily and reproducibly only when the diameter range of the roller resulting from the grinding is matched to the curvature of the cooling device. There 10% of the maximum roller diameter, the number of cooling devices required for different roller diameters, which necessitates a sophisticated roller logistics, is necessary. It is to be noted as a disadvantage that no adjustment of the curvature of the cooling device to the changed roll diameter for each frame and after each work roll change is possible and thus changes the distance of the nozzle or holes to the roll surface and thus the cooling effect during the rolling process from roll change to roll change.

A low pressure cooling in the form of a flow cooling is in the DE 36 16 070 C2 described, wherein in a defined relatively narrow gap between the work roll surface and a cooling shell, the cooling liquid is guided in a directed manner and with external pressure on the roll surface. The pressure level is lower and depends on gap width and flow velocity. Higher cooling effects are achieved here by higher flow velocities. Due to the lower pressure level, the system has no cleaning effect on the roll surface. A disadvantage of this device is that a separate cooling block is necessary for each roller, since this is mounted on the roll chocks. For a conventional hot rolling mill, therefore, a large number of these cooling blocks is required. The adaptation of the gap width to different work roll diameter and the consequences of the cooling block of the respective work roll position has also proved to be disadvantageous or very complicated, since the adjustment of the gap must be done manually and outside of the rolling mill.

Based on the described prior art, it is an object of the invention to provide a method and a cooling device with which or the rolls of a rolling mill are optimally cooled to protect them from thermo-mechanical fatigue and wear, with energy considerations such as minimizing the required coolant flow and the cooling liquid pressure as well as the resulting design and manufacturing costs.

The stated object is achieved procedurally with the features of claim 1 and device with the features of claim 11, characterized in that the rolls are also subjected to high-pressure cooling at the same time as the low-pressure cooling, wherein the rollers sprayed in the high-pressure cooling directly with a high pressure cooling liquid become.

In principle, all rolls of a roll stand can be cooled with the cooling device according to the invention; In particular, however, the invention finds application in the work rolls.

Conveniently, about 20% of the total amount of coolant liquid supplied to the high pressure cooling system and about 80% of the total amount of cooling liquid to the low pressure cooling system generating the main cooling effect. The cooling liquid can be taken from a high tank, for example 7-12 m high, or generated directly by low-pressure pumps. The required pressure range for the cooling liquid of the low pressure roller cooling is dependent on the thermal load of the rollers and is between z. B. 0.5 to less than 5 bar. As a constructive embodiment, a spray cooling, coolant curtain, gap cooling or flow cooling, highly turbulent cooling ( FIG. 2 ) or a combination of the various low-pressure systems.

For high-pressure roll cooling, which at the same time fulfills the task of roller surface cleaning or removal of scale, a single-row or double-row spray bar can be used, as in conventional systems. The small amount of cooling liquid of about 20% of the total amount of cooling liquid is sufficient for this task, wherein a pressure range for the cooling liquid between 5 - 50 bar, preferably 12 bar is required. The used pressure range for the cooling liquid of the high-pressure roll cooling depends on the rolling parameters thickness reduction, specific surface pressure in the roll gap, rolling speed, strip temperatures, roll material and rolled material.

• Energiebedarf der Pumpe (ohne Berücksichtigung des Pumpenwirkungsgrades) am Beispiel für eine 2m-Warmbandstraße mit 5000 m³/h Gesamt-Walzenkühlmittelstrom (Pumpenleistung = Volumenstrom * Druckerhöhung (Hinweis: 36 ist ein Umrechnungsfaktor)

From an environmental point of view, a reduction in the total energy consumed by the pumps while simultaneously fulfilling all system tasks in terms of "green plant technology" is advantageous. Comparing the pumping energy of conventional higher pressure roller cooling with the proposed combined low pressure, high pressure, low pressure cooling system results in the following differences:

• Energy demand of the pump (without consideration of the pump efficiency) using the example of a 2m hot strip mill with 5000 m ³ / h total roller coolant flow (pump capacity = flow rate * pressure increase (Note: 36 is a conversion factor)

• Druckniveau z. B. 12 bar
• Pumpenleistung = 5000 m³/h * 12 bar/36
• Pumpenleistung = 1667 KW

Conventional roll cooling:

• Pressure level z. B. 12 bar
• Pump capacity = 5000 m ³ / h * 12 bar / 36
• Pump power = 1667 KW

• Druckniveau z. B. 12 bar
• Hochdruckkühlmittelmenge 1000 m³/h und
• Druckniveau z. B. 2 bar
• Niederdruckkühlmittelmenge 4000 m³/h
• Pumpenleistung = 1000 m³/h * 12 bar/36 + 4000 m³/h * 2 bar/36
• Pumpenleistung = 333 KW + 222 KW = 555 KW

Combined low pressure high pressure cooling:

• Pressure level z. B. 12 bar
• High pressure coolant quantity 1000 m ³ / h and
• Pressure level z. B. 2 bar
• Low pressure coolant 4000 m ³ / h
• Pump capacity = 1000 m ³ / h * 12 bar / 36 + 4000 m ³ / h * 2 bar / 36
• Pump power = 333 KW + 222 KW = 555 KW

With the combined low pressure high pressure cooling a much smaller amount of energy is needed. For the above example, this results in a reduction of the drive power for the pumps of about 1.1 MW.

With increased dirt or scale particles as well as, for example, rough roll surface or a fire crack pattern, the pressure level can be increased accordingly. Through a camera, the roll surface can be observed to derive therefrom the pressure level change. Furthermore, in order to influence the oxide layer thickness on the roll, the pressure level can be adjusted individually in steps (for example by switching on or off of pumps) or steplessly.

The combined low-pressure high-pressure cooling is provided for example for the front stands of a hot strip mill. In the rear scaffolds, a pure low-pressure cooling can then be used.

The high-pressure chilled beam can act over almost the entire length of the bale or be movable in the width direction and with a local cooling effect. If only a simple low-pressure shell cooling is used in an application, then a combination with the cooling according to the Japanese patent application JP 07290120 conceivable and intended. Here, with the help of an engine, two spray nozzle beam sections are moved axially or in the width direction, and the work roll is locally cooled differently. Instead of an electric or hydraulic motor with threaded rod or two motors for separate adjustment on the left and right side are preferably alternatively a hydraulically movable single or multi-articulated rocker with spray bars mounted thereon or rotatable nozzle units executable to the coolant jets on the desired areas of the work roll (within or next to the belt area) to positively influence the belt profile and flatness.

Analogous to the embodiment with the spraying in the width direction spray bar sections, for example, for a segment of the low-pressure shell cooling short segmental shell parts with a width of, for example 150 mm axially adjustable in the width direction and be executed only locally (eg symmetrically at two points of the work roll) acting.

The low-pressure work roll cooling used in the invention has the task optimally and efficiently to cool, despite the low coolant pressure, the cooling effect (heat transfer from the roller to the coolant) should be high. This causes a lower roll temperature or can be used to reduce the amount of cooling liquid. As efficient low-pressure roll cooling, a flow cooling is preferably used, in which the cooling liquid is conducted past the roll surface in a relatively narrow gap between the work roll and an arc-shaped cooling shell.

According to the invention, the cooling device consists essentially of articulated interconnected movable cooling shell segments. Preferably, three, but usually two cooling shell segments are used. In special cases, however, only one cooling shell segment can be used. The individual cooling-cup segments preferably have joints or joint halves laterally or at their ends. At least one pivot point is present on the middle cooling-plate segment, which receives at least one, preferably two cylinders (hydraulic or pneumatic cylinders). The cylinders have their second breakpoint on the other members of the adjacent cooling shell segments. The cylinders can be arranged in the middle of the cooling beam or at the edges on both sides. Instead of the shell adjustment with cylinders an adjustment with, for example, hydraulic motors or electric motors is conceivable. On the middle cooling shell segment is the console or the cooling beam support with mounting holes. About the cooling beam support, it is possible to move the middle cooling shell segment and thus all components that are connected to this, with a horizontal, vertical and rotating movement is possible. The position adjustment is carried out with a multi-link linkage, which is operated pneumatically, hydraulically or electromechanically. Also is an advantageous employment of the middle Kühlbalkenträgers in the horizontal direction over, for example, a longitudinal or slot guide and pneumatic or hydraulic cylinder possible.

• Kalibrieren der Kühlschalen
  Zum Einstellen der Positionen der Kühlschalensegmente werden die Kühlbalkenträgeranstellung und die Kühlschalensegmente mit den zugeordneten Zylindern und Gelenkgetrieben mit definiertem Druck gegen die Walze angedrückt. In dieser Position werden die Weggeber auf Null gesetzt. Ausgehend hiervon und mit Kenntnis der geometrischen Zusammenhänge kann danach ein definierter Spalt zwischen Kühlschalensegment und Walze eingestellt werden. Der Kalibrierprozess des Kühlsystems kann während der Gerüstkalibrierprozedur durchgeführt werden.
• Berechnen der Positionen
  Da die geometrischen Zusammenhänge (Walzendurchmesser, Walzenpositionen in vertikaler Richtung, Zylinderpositionen, Abstände der Gelenke und Drehpunkte, Position des mehrgliedrigen Gelenkgetriebes etc.) bekannt sind, kann in guter Näherung die Schalenposition bzw. mittlere Spaltbreite errechnet werden. Jede relative Änderung der Walzenposition (bei z. B. Banddickenänderung) während des Walzprozesses ist so umrechenbar.
• Einsatz von Sensoren
  Durch Einsatz von Abstandssensoren kann der Spalt direkt gemessen und die Zylinder und Gelenkgetriebe entsprechend mit einem Regelsystem eingestellt werden.

The cylinders have position measuring systems and pressure transmitters. The position of the cylinders and thus the gap setting or distance determination between cooling shell segment and roller as well as the monitoring of the set positions can be determined and carried out in the following different ways, whereby a combination of the mentioned methods is possible:

• Calibrating the cooling shells
  For adjusting the positions of the cooling shell segments, the cooling beam support position and the cooling shell segments with the associated cylinders and joint drives are pressed against the roll with a defined pressure. In this position, the position encoders are set to zero. Based on this and with knowledge of the geometric relationships, a defined gap between the cooling shell segment and the roll can then be set. The calibration process of the cooling system may be performed during the framework calibration procedure.
• Calculate the positions
  Since the geometric relationships (roll diameter, roll positions in the vertical direction, cylinder positions, distances of the joints and pivot points, position of the multi-joint joint gear, etc.) are known, the shell position or average gap width can be calculated to a good approximation. Any relative change in roll position (eg, tape thickness change) during the rolling process is thus convertible.
• Use of sensors
  By using distance sensors, the gap can be measured directly and the cylinders and linkages adjusted accordingly with a control system.

Compared to a cooling device according to the prior art, the cooling device according to the invention adapts to the respective roll diameter and roll positions due to the existing hinge mechanisms, since the adjustment systems of the cooling beams are connected to the thickness control and follow the vertical movement of the work rolls, for example in the case of a thickness changeover. When driving up the scaffolding (for example, in an emergency on) the cooling shells are automatically pivoted back slightly.

The cooling device forms in a structural embodiment by means of a sealing function a space from which only a small amount of cooling liquid enters the environment. The seal is made by conditioning the shell at the top and bottom of the work roll, which can be pressed with a predetermined pressure and / or by applying a dynamic pressure on the edge of the cooling shells. By this arrangement, it becomes possible to form an almost closed cooling circuit.

At the cooling device, the cooling bars can be fixed with cooling shells and conventional high and / or low pressure spray bars. By positioning the shells just in front of the roller, a gap is formed through which the coolant flows. The gap widths between the cooling shell and the work roll are adjusted in a targeted and reproducible manner during operation, independently of the roll diameter, between 2 and 40 mm, for example to 5 mm. The gap between the work roll and the cooling shell can be approximately equal to -tangential- or the shell is made narrowing toward the outlet.

When using the flow cooling provided according to the invention, two different cooling variants are possible, the partial flow cooling and the continuous flow cooling.

The sectional flow cooling is divided into sections. The cooling liquid flows from an example funnel-shaped rectangular slot in the individual areas of the cooling shell against the roller and is deflected to both sides (up or down) or only primarily to one side, the cooling shell enforces a flow along the roller. By the flow deflection and by flow with higher relative speed along the roller, the cooling liquid absorbs the heat of the roller efficiently. The heated coolant then flows backwards making room for new cold coolant. The chilled beams are designed in such a way that the cooling liquid flowing to the rear (away from the roller) can flow off well, especially on slopes. By means of baffles, the returning coolant on the upper side is additionally directed to the side in order to reduce the pool effect over the wiper. The individual cooling areas are separated from each other by mutual shielding, so that the cooling liquids of the adjacent cooling bars hardly interfere with each other.

In a continuous flow cooling, the cooling liquid is passed over a larger contiguous angular range of the roller. A low adaptable gap width and high flow velocity are required to produce good heat transfer. Slit width and coolant volume must therefore be coordinated. The contiguous flow cooling can be operated in countercurrent or DC principle. Due to the long path between inlet and outlet side, a lateral sealing of the cooling shell is required. As an alternative to the counter or DC principle, an operating mode can also be carried out in which the cooling liquid is supplied to the upper and lower cooling beam pipelines. The process is then targeted to the pages. In this principle, initially the cooling fluid flowing tangentially to the roller absorbs the heat and is then deflected to the side. The warm coolant heats the roller areas next to the belt running area and leads there to the desired positive influence of the thermal crowns. This system is particularly effective when zone cooling is performed, where the areas next to the belt are not directly cooled.

When zone cooling only certain areas are released for the flow in the roll length in Kühlmittelzuführkanal of the cooling beam or narrow cooling shells with differently adjusted gap widths spaced next to each other. Due to the different gap widths result for the narrow cooling shells a corresponding different specific coolant flow and thus each cooling shell a different cooling of the work roll. To separate the different coolant flow rates, depending on the design, a barrier cooling liquid or a gap seal is introduced between the narrow cooling shells.

• Einstellung der Kühlmittelmenge und Druckniveau für den Niederdruckund ggf. für den Hochdruckteil abhängig von Banddickenabnahme, spezifische Flächenpressung im Walzspalt, Walzgeschwindigkeit, Bandtemperaturen, Walzenwerkstoff und gewalztes Material sowie der gemessenen und/oder der berechneten Walzentemperaturen und/oder beobachteten Walzenoberfläche und ebenfalls abhängig von der eingestellten Kühlmittel-Beaufschlagungsbreite,
• Einstellung der Kühlmittelmenge über der Bandbreite durch Verstellung der Austrittsöffnungen des Zuführkanals (parabolisch, Kurve höherer Ordnung oder zonenweise) oder/und Verstellung der Spaltbreite zwischen Kühlschale und Arbeitswalze in Abhängigkeit der Bandbreite und/oder Einstellung der Position der in Breitenrichtung verstellbaren Spritzdüsenbalkenabschnitte und/oder gemessenem Profil- und Planheitszustand über der Bandbreite,
• Austausch von Signalen mit der Dickenregelung (Gerüstanstellung),
• Beschreibung der geometrischen Zusammenhänge der beweglichen Teile der Kühleinrichtung sowie Berücksichtigung der Anstellposition, Passlineposition und Arbeitswalzendurchmesser zwecks optimaler Positionsermittlung bzw. Berechnung der Positionsänderungen,
• Festlegung der Anschwenkposition von Kühlbalkenträger sowie Kühlschalenanstellposition mit Hilfe der Zylinder unter ggf. Verwendung der Druck- und Weggebersignalen,
• Steuerung der Kalibrierprozedur für die Kühlschalenpositionen.

For optimum control of the cooling device, a calculation model (process model or level 1 model) is used which fulfills the following tasks:

• Adjustment of the coolant quantity and pressure level for the low pressure and possibly for the high pressure part depending on strip thickness, specific surface pressure in the nip, rolling speed, strip temperatures, roll material and rolled material and the measured and / or calculated roll temperatures and / or observed roll surface and also dependent on the set coolant Beaufschlagungsbreite,
• Adjustment of the coolant quantity over the belt width by adjusting the outlet openings of the feed channel (parabolic, higher-order or zone-wise) and / or adjusting the gap width between cooling shell and work roll as a function of the belt width and / or adjusting the position of the widthwise adjustable spray jet beam sections and / or measured Profile and flatness condition over the bandwidth,
• Exchange of signals with thickness control (scaffolding),
• Description of the geometric relationships of the moving parts of the cooling device as well as consideration of the setting position, passline position and work roll diameter for the purpose of optimal position determination or calculation of the position changes,
• Determining the pivoting position of cooling beam support and Kühlschalenanstellposition using the cylinder under the use of the pressure and Weggebersignalen, if necessary
• Control of the calibration procedure for the cooling pan positions.

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

Further details of the invention are explained in more detail below with reference to exemplary embodiments illustrated in schematic drawing figures.

Fig. 1

eine Sprühkühlung nach dem Stand der Technik,

Fig. 2

eine hochturbulente Strömungskühlvorrichtung nach dem Stand der Technik,

Fig. 3

eine erfindungsgemäße Kühlvorrichtung mit mehreren Kühlschalensegmenten, die gelenkig miteinander verbunden sind,

Fig. 4

die Kühlvorrichtung der Fig. 3 mit alternativer Kühlflüssigkeitsströmung,

Fig. 5

eine erfindungsgemäße Kühlvorrichtung mit radial geteilter Kühlschale

Fig. 6

die Kühlvorrichtung der Fig. 5 mit austauschbarer Kühlschale bzw. Kühlplatte,

Fig. 7

eine Kühlvorrichtung mit durch Federn angepresste Kühlschalensegmente,

Fig. 8

eine Kühlvorrichtung mit Walzspaltkühlung / Walzspaltschmierung und kombinierter Niederdruck-Hochdruckwalzenkühlung,

Fig. 9

eine Kühlvorrichtung mit in den Kühlschalen eingebrachte Löcher,

Fig. 10a-f

Düsen- und Schalenausbildungen,

Fig. 11a-c

eine Spaltbreitenverstellung,

Fig.12

eine Spaltbreitenverstellung,

Fig. 13

eine Zonenkühlung,

Fig. 14

eine Spaltabdichtung,

Fig. 15a, b

eine örtlich wirkende axial verstellbare Walzenkühlung,

Fig. 16

Biegefedern als gelenkige / elastische Verbindung zwischen benachbarten Kühlschalensegmenten.

Show it:

Fig. 1

a spray cooling according to the prior art,

Fig. 2

a highly turbulent flow cooling device according to the prior art,

Fig. 3

a cooling device according to the invention with a plurality of cooling shell segments, which are hinged together,

Fig. 4

the cooling device of Fig. 3 with alternative coolant flow,

Fig. 5

a cooling device according to the invention with radially divided cooling shell

Fig. 6

the cooling device of Fig. 5 with exchangeable cooling shell or cooling plate,

Fig. 7

a cooling device with cooling shell segments pressed by springs,

Fig. 8

a cooling device with roll gap cooling / roll gap lubrication and combined low pressure high pressure roll cooling,

Fig. 9

a cooling device with holes introduced into the cooling shells,

Fig. 10a-f

Nozzle and bowl designs,

Fig. 11a-c

a gap width adjustment,

Figure 12

a gap width adjustment,

Fig. 13

a zone cooling,

Fig. 14

a gap seal,

Fig. 15a, b

a spatially acting axially adjustable roller cooling,

Fig. 16

Bend springs as articulated / elastic connection between adjacent cooling shell segments.

In the FIG. 1 a spray cooling according to the prior art is shown, in which a cooling liquid 7 is sprayed by means of nozzles 27 on the roll surface of the work rolls 1, 2. Due to the relatively large distance between the nozzle and the roller, a higher coolant pressure range (eg 6 ... 15 bar) is selected. Inlet and outlet side arranged scrapers 17 ensure that as little as possible cooling liquid can come into contact with the rolling stock 4.

The FIG. 2 shows another known way to cool the work rolls 1, 2. This is a highly turbulent cooling in the low pressure range. Water is sprayed onto the roll surface of the work rolls 1, 2 with the aid of inlet-side arranged nozzles 27 and through the outlet side in the concavely curved contiguous cooling shell 11, and a water cushion with a turbulent and non-directional flow is formed in front of the work roll. The replacement of the water is relatively slow in this construction, which negatively affects the cooling efficiency.

A continuous flow cooling according to the invention with a contiguous cooling shell 11 is in the FIG. 3 shown. The cooling device 10 according to the invention consists here essentially of articulated cooling shell segments 13 which enclose the work rolls 1, 2 at a distance, forming a gap 30 in a larger angular range.

Due to the claimed articulated connection between the individual cooling segments of a cooling shell, an optimal adaptation of the cooling shell to the individual diameters of the rolls and thus an energetically more favorable cooling of the rolls is advantageously possible. The hinge axis of the articulated connection is preferably parallel to the longitudinal axis of the roller.

Via a feed tube 25 and the inlet opening 29, the cooling liquid 7 flows in countercurrent to the rolling direction 5 in the gap 30 to then flow through the outlet opening 24 and the discharge pipe 26 again. If the discharge pipe 26 or the outlet opening 24 is closed or not carried out in a special case, it is possible to selectively generate a coolant outlet transverse to the roll. Side seals are then only partially available here. The segment lengths of the cooling-cup segments 13 forming the gap 30 should be approximately the same, so that when the diameter of the work-roll 1 changes, the cooling-cup segments 13 can follow the change in curvature of the roll-jacket surface 6 optimally. The individual cooling-cup segments 13 have at their ends joints or joint halves which, connected to one another, form a corresponding number of pivot pivots 22 and pivot points 21 which are connected to one another by cylinders 20, for example hydraulic or pneumatic cylinders. On the middle cooling shell segment 13 is the cooling beam support 16 with a pivot point 23, by which it is possible, the cooling shell segments 13 and all components that are connected to this, in the illustrated (horizontal, vertical and rotating) adjustment directions 45 of the cooling beam carrier with a To move not shown here multi-link linkage. A stripping device 17 arranged below the cooling shell 11 ensures that as little cooling liquid 7 as possible reaches the rolling stock 4.

Via sensors 37 for distance measurement, pressure gauges 36 in the cylinder connection lines and odometer 39 arranged on or in the cylinders 20, a positioning of the entire cooling shell 11 can be carried out. With temperature sensors 38 (in roll center or across the width) becomes continuous the roll temperature is measured in order to regulate the size of the gap 30 to maintain the desired cooling effect.

The cooling devices described below are structurally constructed in a similar manner, which is why the equivalent details concerning the construction are no longer described, but in some cases only the reference numbers already mentioned above are shown.

An alternative flow guidance of the cooling liquid 7 within the gap 30 formed by the cooling shell segments 13 of the cooling shell 11 and the roll shell surface 6 in relation to that in FIG FIG. 3 described flow is in the cooling device 10 of FIG. 4 shown. The supply pipes 25 for the low pressure ND to be used cooling liquid 7 are arranged here respectively at the upper and lower cooling shell segment 13, so that here the Kühlflüssigkeitsteilmengen in countercurrent and in cocurrent, based on the Walzendrehrichtung 5, are guided through the gap 30. The flow directions are indicated by arrows 43. To seal the gap 30, the upper and lower edges of the cooling shell 11 are formed with a contact surface 46, for example a hard tissue plate, which is sealingly guided against the roll shell surface 6. Thus, since only a lateral flow of the cooling liquid 7 from the gap 30 is possible (discharge pipes are not present), the gap 30 with respect to the gap width of Fig. 3 increased. The adjustment of the individual cooling shells takes place as in FIG. 3 by means of cylinder 20. Instead of Zyünder can be used there also simplified coil springs. In addition to the cooling performed on the outlet side with the cooling shell 11 arranged there, each work roll 1, 2 is also cooled on the inlet side. Since the achievable cooling is not the main focus here ranges for. B. spray cooling with low pressure ND by means of nozzles 27th

A cooling device 10 with a section-wise low-pressure flow cooling shows the FIG. 5 , In contrast to the Figures 3 and 4 in which the cooling shells 11, although composed of cooling shell segments 13, but coherently form a uniform in itself movable cooling shell 11, the cooling shell segments 13 of the now radially divided cooling shell 12 are also spatially separated from each other and form separate Strömungskühlbereiche s1, s2, s3. From low pressure (ND) supply pipes 25, the cooling liquid flows through a funnel-shaped discharge slot 44 in the central region of a cooling shell segment 13 from an outlet opening 24 against the work roll 1, 2 and is deflected upwards and downwards on both sides. In order to limit the transverse (in the width direction) flowing amount of water, mechanical side seals can be arranged. Each cooling shell segment 13 forces a flow according to the arrows 43 along the roll surface 6 and then back to the rear. The cooling-cup segments 13 are designed so that the cooling liquid flowing to the rear (away from the roller) can flow off well with a gradient. By (not shown) baffles, the back flowing coolant on the upper side is additionally directed to the side in order to reduce the pool effect on the scraper 17. The outlet openings 24 of the cooling-cup segments 13 can be provided with an exchangeable mouthpiece (for example a rectangular nozzle) so that, if required, the cross-section and the shape can be adapted to slightly changed conditions. Between the scrapers 17 and the cooling shells 12 high pressure (HD) nozzles are arranged in this embodiment, by means of which the inventively combined low-pressure high-pressure cooling is realized. As shown, the high-pressure spray bar can be arranged separately on the cooling beam carrier 16 or attached to a cooling shell segment, so that it can be adjusted with it.

In the FIG. 6 is indicated that on the cooling beam of the cooling device 10 is a completely replaceable cooling plate 47 is attached. Since here too the mouthpieces of the nozzle openings of the outlet openings 24 can be exchanged, so the possibility of changing the entire cooling shell with mouthpiece or separately is possible. The cooling shells of a flow cooling region may also be divided into two, so that the outlet opening 24 is slightly displaced by relative displacement and subsequent fixing of the two halves is adjustable. Furthermore, slightly different shell thicknesses or gap widths per cooling beam can be set and the amount of coolant flowing upwards and downwards can be influenced.

Instead of the previous embodiments of the FIGS. 3 to 6 Cylinder for employment of the individual shells, is in the cooling device 10 of FIG. 7 an alternative solution is disclosed and illustrated. Here, the cooling beam support 16 is positioned with the middle cooling shell segment 13 in front of the roller. The other two cooling-plate segments 13 are laid against the work rolls 1, 2 with the aid of a straight or curved crossbar 48, which can be rotated in a small defined area, with a corresponding spring contact pressure of the spring 8. Alternatively, also in the area of the cylinders (see Figures 3 - 6 ) Coil springs 8 are mounted with corresponding brackets at the ends. The gap 30 is determined by spacer plates 49 between the cooling shell 13 and the work roll 1, 2. As a material for the spacer plates z. As hard tissue, aluminum, cast iron, even lubricating metals or plastic. The spacer plates 49 are arranged only in the chilled beam edge region so as not to disturb the coolant flow in the middle. Optional spacer plates 49 are also conceivable over the cooling beam length. These can serve as distance adjustment or for influencing the flow direction of the coolant. These spacer plates may also be mounted on the middle cooling cup segment 13 (not shown). By a generated coolant flow to the side of the edge areas of the work roll are heated (in addition to the band) targeted by the heated coolant from the middle.

If the work roll diameter ranges, in which the cooling is operated, small or per scaffold in the same area, so a special case, a rigid cooling system, ie provided with immobile cooling shells (without cylinder between the shells and without springs 8). Also, it is then advantageously possible to use rigid spacer bars instead of movable cylinders 20. The gaps between the roller and the cooling pan then vary slightly, however the system with the partial flow cooling is still effective and the system is easier to manufacture. It must only be positioned depending on the work roll diameter and the work roll position in front of the roller so that the gap optimally, so the outlet openings are arranged relatively close in front of the roller depending on the work roll diameter. The design can be carried out the same for multiple scaffolding and the adaptation to the different framework diameter ranges of a rolling train is carried out only on the length-adjustable rods.

In the cooling device 10 of FIG. 8 In addition to the previously described combined low-pressure high-pressure cooling, there is also arranged a low-pressure flow cooling with integrated roll gap lubrication 19 and roll gap cooling 18 on the inlet side. At the same time, in the Fig. 8 discloses how different high and low pressure systems can be combined. The flow of the cooling liquid 7 can share under a cooling shell or, as shown here for example on the inlet side and outlet side, a larger amount of coolant are preferably directed in one direction. In order to increase the heat transfer, a flow against the direction of rotation is advantageous.

The area in which the nip lubrication 19 is arranged, is largely kept dry by the generated flow direction of the work roll cooling and / or provided with an elastic plastic surface cooling shells 50 or cooling shells 51 with elastic plastic or hard tissue plates, including the cooling beam support mechanism, a slight contact pressure is generated over the plates on the roller. The plates themselves are designed to be continuous across the width and have by their structural design (not shown) an elastic effect. The area of the roll surface (seen in the direction of rotation) prior to the application of the rolling gap lubricant is optionally carried out with a (not shown) compressed air spraying in order to blow the roll surface defined dry.

Instead of the use of, for example, three cooling bars with a rectangular nozzle, it is according to the cooling device 10 of FIG. 9 also possible to carry out the three chilled beam with replaceable cooling shells 47, in which many staggered holes 52 are drilled from which individual coolant jets from a short distance against the rollers 1, 2 inject. Even so, a partial flow cooling can be established. The holes are arranged offset in the width direction so that a uniform cooling effect across the width. The cross-sectional size and distances of the holes 52 can be designed differently over the bale width, so that a coolant crown can also be produced with this system. The holes 52 can be aligned perpendicular to the rollers 1, 2 or allow an oblique injection of the cooling liquid against the rollers 1, 2.

In a special variant, not shown, it is provided to make the cooling shells so that the coolant outlet opening are performed by a rectangular slot 24 and 44 combined with holes 52 in the plate simultaneously to increase turbulence in the flow gap.

Fig. 10a

eine symmetrische Anordnung des unteren Teils des Kühlbalkens 54 auf der Kühlschale 11, 12 mit austauschbarer Düse 27,

Fig. 10b

Kühlflüssigkeitsaustritt aus der Düse 27 mit Winkel α schräg zur Walze,

Fig. 10c

Düse 27 mit alternativer Querschnittsform sowie mögliche Ausführungsformen der Stege bzw. Rillen 9,

Fig. 10d

asymmetrisch zur Düse 27 verkürzte bzw. verlängerte Kühlschale 11, 12.

Further details on the nozzle and bowl design are the FIGS. 10a to 10f can be seen, wherein the arrangement of the nozzle in the middle of the bowl or alternatively in a symmetrical arrangement with one side, for example, above shortened running shell takes place. By changing the angle of attack of the nozzle or different cooling shell thicknesses up / down (not shown), the distribution of the cooling liquid flow up and down can also be influenced. Also, various nozzle shapes (beam focusing or "atomizing") are indicated. The cooling shell may additionally be provided on the side facing the rolls smooth or with grooves or webs 9 in order to positively influence the cooling effect by causing turbulence. In detail are shown:

Fig. 10a

a symmetrical arrangement of the lower part of the cooling bar 54 on the cooling shell 11, 12 with replaceable nozzle 27,

Fig. 10b

Coolant outlet from the nozzle 27 at an angle α oblique to the roller,

Fig. 10c

Nozzle 27 with alternative cross-sectional shape and possible embodiments of the webs or grooves 9,

Fig. 10d

Asymmetrical to the nozzle 27 shortened or extended cooling shell 11, 12th

If necessary, the funnel-shaped outlet opening formed in the flow direction can be designed with baffles in order to direct the coolant inwardly, outwardly or straightforwardly, so that ultimately a closed and uniform coolant-liquid jet emerges over the length of the cooling-bar. A funnel-shaped design of Kühlflüssigkeitszuführkanals to the chilled beam broadsides is possible to reduce the under the shell transverse to the side (beam edges) flowing Kühlflüssigkeitmenge.

Furthermore, it is possible to form the cooling shell in sections over the cooling beam length with a gap width adjustment in Kühlflüssigkeitszuführkanal and thus to influence the coolant distribution and the cooling effect over the roll length. In order to be able to carry out a parabolic change in the gap width of the outlet opening over the width in a simplified manner, according to the example of FIG FIGS. 10e (Side view) and 10f (top view) with an adjusting mechanism (not shown) bendable spring plates 53 disposed within the funnel-shaped feed channel 55. In the normal position here are the spring plates on the side surfaces of the outlet opening. If the middle is turned on one side, the gap is reduced there. The edges are held in a slot guide. When the spring plate is set at the two edges, alternatively the gap width is reduced there.

The embodiment according to FIG. 10e and FIG. 10f represents only the principle dar. There are also other constructions with the same effect possible.

Details for an exemplary embodiment of the gap adjustment in the feed channel 55 are in the FIGS. 11a to 11c in side view and in the FIG. 12 shown in the corresponding plan view. Here, the elongated outlet cross-section 58 of the cooling bar is divided into individual width sections 59. For each width section 59, the flow opening b and thus the volume flow of the cooling liquid can be adjusted individually. The width section 59 can be designed, for example, 50-500 mm wide. Alternatively, a paired, symmetrically arranged to the frame center control of the zone cooling (gap setting) is possible. All the cooling bars of a scaffold can be provided with zone-by-zone control of the cooling cross-sections and the zones can be correspondingly connected, or the individual bars of a scaffold can be controlled separately. As a closing mechanism of the outlet cross-section is for the embodiment in FIG. 11 a system operated with air pressure or fluid pressure. Depending on the pressure level of the system or on the measured volume flow, the flow opening b can be adjusted from open to partially open or closed. Instead of stretchable plastic bottles 60 arranged in sections, it is also possible to use rotary or displaceable flaps or tappets, eccentric adjustments or other mechanical actuators for segment-wise influencing of the cross section of the outlet opening.

In the embodiment of FIGS. 11a to 11c is arranged laterally on the feed channel 55 as a closure member, a pressure chamber 56, the expandable plastic tube 60 forms part of the feed channel 55. In the initial state of FIG. 11a is the air chamber 56 in the unpressurized state, so that, as in the FIG. 12 shown at the width section 59a, the flow opening b is fully open. In the FIG. 11b The pressure chamber 56 was partially filled with compressed air or a liquid via a pressure line 57, whereby the plastic tube 60 was partially pressed into the feed channel 55 and the Flow opening b is now partially closed, as in FIG. 12 at the width section 59b is shown. A completely closed flow opening b shows the FIG. 12 at the width section 59c. Here was accordingly the FIG. 11 c completely filled the pressure chamber 56 and thus shut off the feed channel 55 in this area. By closing the zones, the thermal expansion of the roll and thus the strip profile and the strip flatness can be positively influenced. Closing the cooling zones next to the belt while adjusting (reducing) the water flow rate can advantageously contribute to further energy reduction.

Another operating principle of zone cooling is in FIG. 13 shown. In this case, narrow cooling shells 14 are arranged side by side in roll length, the columns 31, 32, 33 can be adjusted with different gap widths W1, W2, W3. By different gap widths and a different loading of the columns 31, 32, 33 with pressure and volume flow of the cooling liquid so a different specific coolant flow 41 per unit time can be generated over the roller length. To separate the individual zones with different coolant flow 41 per unit of time, a barrier cooling liquid generating a dynamic pressure can be introduced into the gap 34 existing between the cooling shells 14. In a simplified manner, a cooling shell without adjusting device can be designed such that the gap between the cooling shell and the roll is arbitrarily different over the length of the roll.

As material for the cooling shells 13,14 can be used with advantage a material which may rest against the roller without damaging it and is elastic. These may be, for example, a sand-free cast iron, lubricious plastic, self-lubricating metals, aluminum or hard tissue.

In the FIG. 14 is shown a possibility for sealing the gap 30 formed between the work roll 1 and the cooling shell 14 at its edges. Via a pipe 25 and a nozzle 27 is a fluid jet 28, for example Air or coolant, selectively injected into the opening of the gap 30. The fluid jet 28 thus generates a back pressure, which prevents the escape of the cooling liquid 7 from the gap 30.

A locally acting axially adjustable work roll spray cooling, which can be performed as high pressure as well as low pressure cooling, show FIGS. 15a and 15b , This cooling is an additional cooling and can be operated in combination with the low-pressure shell cooling, not shown. The local positioning of the spray nozzles or application of the cooling liquid 7 preferably takes place as a function of the profile and flatness control or regulation. In FIG. 15a For this purpose, the spray nozzle bar sections 40 'are moved on a guide rod 63. The positioning of the two spray nozzle bar sections 40 'takes place symmetrically to the center of the roll with the aid of a hydraulic cylinder 61, linkage rods 62 and nozzle beam carrier 64. Alternatively, two hydraulic cylinders 61 are also conceivable which individually position both sides 65. The feeding of the spray nozzle bar sections 40 'takes place individually on the right and left via the respective feed line 25. A similar arrangement of a spatially acting work roll cooling provides FIG. 15b With a hydraulic cylinder 61, articulated rods and articulated arms 62 with spray nozzle bar sections 40 'mounted thereon are moved via a pivot point 66 on a circular path 64, and the cooling jet 7 is directed to different positions within or next to the band area on the work roll 1. As alternatives not shown for articulated rocker arm, the two spray nozzle bar sections 40 'each with a coupling gear (4-joint arc) are moved when a movement on a circular path 64 should be avoided. The use of electric or hydro-stepping motors at the positions of the pivot points 66 for the direct movement of the nozzle units on the spray nozzle bar sections 40 'via a bar on the circular path 64 are also possible.

The low pressure cooling system is also alone, ie not usable in combination with the high pressure cooling system.

Fig. 16 shows bending springs 8 as an elastic connection between the adjacent cooling shell segments 13.

LIST OF REFERENCE NUMBERS

1, 2

Stripper

3

roll width

4

rolling

5

Rolling direction of rotation

6

Rolling surface

7

coolant

8th

feather

9

Grooves or webs

10

cooler

11

coherent cooling shell

12

radially divided cooling shell

13

Cooling shell segments

14

narrow cooling shells

15

Coupling point of the cooling shell

16

Cool beam support

17

scraper

18

Roll gap cooling

19

Roll gap lubrication

20

cylinder

21

Fulcrum of the cylinders

22

Joint pivot point of the cooling shell segments

23

Connecting point of the cooling beam carrier

24

outlet opening

25

feed

26

discharge pipe

27

jet

28

fluid jet

29

inlet opening

30

Gap between roll shell surface and cooling shell

31

Gap with gap width W1

32

Gap with gap width W2

33

Gap with gap width W3

34

Gap between the narrow cooling shells

36

pressure gauge

37

Sensor for distance measurement

38

temperature sensor

39

odometer

40

Spray nozzle bar for high pressure cooling

40 '

Spray nozzle beam section

41

specific coolant flow per unit time

42

Blocking coolant for separating the cooling-plate strips

43

Flow direction of the coolant

44

funnel-shaped dispensing slot

45

possible adjustment directions of the cooling beam holder

46

contact surface

47

exchangeable cooling plate

48

crossbeam

49

spacer plate

50

Cooling bowl with elastic plastic surface

51

Cooling bowl with elastic plastic plate

52

Cooling bowl with holes

53

spring plate

54

lower part of the cooling beam

55

funnel-shaped feed channel

56

pressure chamber

57

pressure line

58

Outlet cross section

59

Width section of the outlet cross-section

60

elastic plastic hose

61

cylinder

62

toggle links

63

guide rod

64

trajectory

65

movable nozzle beam support

66

pivot point

b

flow opening

ND

Coolant inlet Low pressure cooling

HD

Coolant inlet High pressure cooling

s1-s3

Cooling area of the cooling shell segments

Claims (20)

1. Method of cooling the rolls (1, 2) of a roll stand with low-pressure cooling, in which the rolls are acted on by a cooling liquid standing under low pressure, characterised in that the rolls are also subjected to a high-pressure cooling simultaneously with the low-pressure cooling, wherein the rolls during the high-pressure cooling are directly sprayed with a cooling liquid standing under high pressure.
2. Method according to claim 1, characterised in that approximately 20% of the entire cooling liquid quantity of the high-pressure cooling and approximately 80% of the entire cooling liquid quantity of the low-pressure cooling producing the main cooling effect are supplied.
3. Method according to one of the preceding claims, characterised in that for preference a pressure range for the cooling liquid (7) between 0.5 to < 5 bar for the low-pressure roll cooling and a pressure range for the cooling liquid (7) between 5 - 50 bar, preferably 12 bar, for the high-pressure roll cooling are set with the help of a process model in dependence on the rolling parameters of thickness reduction, specific area pressure in the rolling gap, rolling speed, strip temperature, roll material and rolled material.
4. Method according to any one of the preceding claims, characterised in that the low-pressure cooling is formed as a low-pressure spray cooling, as a low-pressure cooling curtain or as low-pressure flow cooling, as low-pressure cooling of high turbulence or in the form of a combination of the said forms of cooling, wherein in the case of low-pressure flow cooling the cooling liquid flows in a gap (30, 31, 32, 33) between the roll surface and at least one cooling shell segment opposite a partial region of the roll surface.
5. Method according to claim 4, characterised in that adaptation of the position of the cooling shell segment (13) to the respective roll diameter and/or roll positions is undertaken for producing a reproducible cooling effect.
6. Method according to one of the preceding claims 4 and 5, characterised in that way of the cooling shells (13) predominantly a coolant flow (43) tangentially along the roll surface (1, 2) is produced or, with the help of spacer plates or spacer strips (49) sealed in tangential direction, a coolant flow or coolant outflow preferably to the side is optionally performed in order to heat the roll region at the edges by warm cooling liquid (7) apart from the strip region in the middle.
7. Method according to claim 6, characterised in that in the case of a coolant outflow conducted preferably parallel to the roll axis the coolant feed near the strip region is blocked by the features of the zonal cooling, for example the cooling shell spacing from the roll (1, 2) or from the coolant feed channel (55).
8. Method according to any one of the preceding claims, characterised in that the cooling intensity of the low-pressure cooling, particularly in the case of the low-pressure cooling curtain or the flow cooling, is set to be different over the roll length.
9. Method according to any one of the preceding claims, characterised in that the nozzle spray bars, which are optionally movable in width direction, of the high-pressure cooling system are utilised for zonal cooling and are constructed axially with the help of electric or hydraulic motors with threaded rods or by hydraulically moved single-element or multi-element articulated transmissions (62) with a spray nozzle bar section (40') attached thereto or rotatable nozzle units, in order to guide the cooling liquid (7) with a directed jet onto the desired region of the roll (1, 2).
10. Method according to any one of the preceding claims, characterised in that a computer model, for example a process model or Level 1 model, is used, which fulfils the following tasks:

    setting of the coolant quantity and pressure level for the low-pressure and high-pressure part in dependence on strip thickness reduction, specific area pressure in the rolling gap, rolling speed, strip temperatures, roll material and rolled material as well as the measured and/or calculated roll temperatures and/or observed roll surface and equally in dependence on the set width of coolant action,

    setting of the coolant quantity over the strip width by adjustment of the outlet openings of the feed channel (parabolic, other curves or zonally) and/or adjustment of the gap width between cooling shell and roll in dependence on the strip width and/or setting of the position of the spray nozzle bar sections, which are adjustable in width direction, and/or measured profile state and planarity state over the strip width,

    exchange of signals with the thickness regulating means,

    description of the geometric correlationships of the movable parts of the cooling device as well as consideration of the adjustment position, pass-line position and roll diameter for the purpose of optimal positional determination or calculation of the position changes, and

    determination of the pivot position of cooling bar carriers as well as cooling shell adjustment position with the help of the cylinders optionally with use of pressure and travel transmitter signals.
11. Cooling device (10) for cooling the rolls (1, 2) of a roll stand with a low-pressure cooling system, in which the rolls are acted on by a liquid standing under low pressure, characterised in that in addition to the low-pressure cooling system a high-pressure cooling system is also provided, which is equipped with spray pipes and nozzles for direct spraying of the rolls with the cooling liquid, which is disposed under high pressure, simultaneously with the low-pressure cooling by the low-pressure cooling system.
12. Cooling device according to claim 11, characterised in that the low-pressure cooling system is constructed for producing a low-pressure spray cooling, a low-pressure cooling curtain or a low-pressure flow cooling or a low-pressure cooling with high turbulence or a combination of the said types of cooling.
13. Cooling device according to claim 12, characterised in that the low-pressure cooling system for producing the low-pressure flow cooling comprises at least one cooling shell (11) with at least one, preferably curved cooling shell segment (13, 52), which together with the surface of the roll (1, 2) to be cooled forms a gap (20), which is fillable with the flowing cooling liquid (7) and which is preferably settable with respect to its gap width in the form of the spacing between the roll surface the cooling shell.
14. Cooling device according to claim 11 to 13, characterised in that the high-pressure cooling system comprises a single-element or multi-element spray nozzle bars (40, 40') with the nozzles for high-pressure cooling of the rolls.
15. Cooling device according to any one of claims 11 to 14, characterised in that in the case of the combined low-pressure/high-pressure cooling system the spray nozzle bars (40, 40') of the high-pressure cooling system are arranged above and/or below and/or within the low-pressure cooling system to be fixed in location or to be movable in width direction.
16. Cooling device according to any one of claims 11 to 15, characterised in that two or more of the cooling shell segments are movably connected together.
17. Cooling device according to any one of claims 11 to 16, characterised in that the movable connection between the cooling shell segments is executed in the form of a universal joint and/or a spring and/or a resilient connection and/or a multi-element articulated transmission arrangement.
18. Cooling device (10) according to one of more of claims 15 to 17, characterised in that at least one of the cooling shell segments (13, 52), for example the middle one, is positionable by the cooling bar carrier (16) in front of the roll (1, 2) and the other cooling shell segments (13, 52) spaced by spacer plates (49) can be urged by way of springs (8) towards the roll (1, 2).
19. Cooling device (10) according to one or more of claims 11 to 18, characterised in that a space, from which a small amount of cooling liquid (7) passes into the environment, is formed between the cooling shells (11, 12) or the cooling shell segments (13) and the roll surfaces (1, 2) with the help of a sealing function or a sealing means by a predetermined pressure towards the rolls (1, 2).
20. Cooling device (10) according to any one of claims 11 to 19, characterised in that the high-pressure cooling system is arranged on the stand outlet side.

Images