EP2403663A1

EP2403663A1 - Method and cooling device for cooling the rollers of a roll stand

Info

Publication number: EP2403663A1
Application number: EP10706548A
Authority: EP
Inventors: Jürgen Seidel; Matthias Kipping; Rolf Franz
Original assignee: SMS Siemag AG
Current assignee: SMS Group GmbH
Priority date: 2009-03-03
Filing date: 2010-03-02
Publication date: 2012-01-11
Anticipated expiration: 2030-03-02
Also published as: EP2403663B1; CN102421541B; WO2010099924A1; CN102421541A; DE102009053074A1; TW201036722A; US20120031159A1; RU2011139995A; RU2483817C1; WO2010099925A1; DE102009053073A1; EP2403663B2; TW201036721A

Abstract

In order to solve the problem of providing a method and a cooling device (10) by means of which the rollers (1, 2) of a roll stand can be optimally cooled, wherein energy aspects, such as minimizing the required cooling fluid stream and the cooling fluid pressure, as well as construction and manufacturing costs, are to be taken into account, the invention proposes cooling the rollers using a combined low-pressure/high-pressure (ND, HD) cooling device.

Description

Method and cooling device for cooling the rolls of a roll stand

The invention relates to methods and a cooling device for cooling the Wa zen, in particular the work rolls of a rolling mill.

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 letting the work rolls cool intensively in order to limit their thermal stress and geometric expansion, the work roll cooling is intended to 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. WO 2008/104037 A1 discloses a cooling device with highly turbulent cooling in the low-pressure region, in which a roll is cooled by means of nozzles or bores arranged on a concave cooling beam. 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 should 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 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 changed.

A low pressure cooling in the form of a flow cooling is described in DE 36 16 070 C2, 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 the gap width and flow speed. 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.

Starting from 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 against thermo-mechanical fatigue and wear, with energetic Ge visual points such as minimizing the required coolant flow and the cooling liquid pressure as well as the resulting design and manufacturing costs.

The object is procedurally achieved with the features of claim 1 and device according to the features of claim 24 solves that the rolls are also subjected to high pressure cooling at the same time as the low pressure cooling, the rollers in the high pressure cooling directly with a high pressure Be sprayed coolant.

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. 0.5 to less than 5 bar. As a constructive embodiment, a spray cooling, coolant curtain, gap cooling or flow cooling, highly turbulent cooling (Figure 2) or a combination of the various low-pressure systems can be used.

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 jet 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 pressure range used for the cooling fluid of the high-pressure roller mill depends on the rolling parameters thickness reduction, specific surface pressure in the roll nip, rolling speed, strip temperatures, roll material and rolled material.

From an environmental point of view, it is advantageous to reduce the total energy consumed by the pumps while fulfilling all system tasks in terms of "green-plant technology." If one compares the pumping energy of conventional higher-pressure roll cooling with the proposed combined low-pressure and high-pressure Cooling system, the following differences arise:

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

Conventional roll cooling: pressure level z. Eg 12 bar pump capacity = 5000 m ³ / h ^* 12 bar / 36 pump capacity = 1667 KW

Combined low-pressure high-pressure cooling: pressure level z. B. 12 bar high pressure coolant amount 1000 m ³ / h and pressure level z. B. 2 bar Niederdruckkühlmittelmenge 4000 m ³ / h

Pump capacity = 1000 m ³ / h ^* 12 bar / 36 + 4000 m ³ / h ^* 2 bar / 36 pump capacity = 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 operate over almost the entire length of the bale or be movable in the width direction and with a localized 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 is conceivable and provided. 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 moving single or multi-link articulated rocker with spray bars mounted thereon or rotatable nozzle units executable to the coolant jets on the desired areas of Ar - to steer the work roll (inside or next to the belt area) in order to positively influence the belt profile and the 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 Kühlflüssig- keitsdruck the cooling effect (heat transfer from the roller to the cooling liquid) 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 adjusting the shells 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. An advantageous employment of the middle ren cooling beam carrier in the horizontal direction over, for example, a longitudinal or slot guide and pneumatic or hydraulic cylinder possible.

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 To adjust the positions of the cooling shell segments, the

Cooling beam support position and the cooling shell segments pressed with the associated cylinders and joint gears with defined pressure against the roller. In this position, the position encoders are set to zero. On the basis of this and with knowledge of the geometrical 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.

Calculating 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 constructive Ausführuπgsform using 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. This arrangement makes it 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. The gap width and cooling liquid quantity must therefore be coordinated. The contiguous flow cooling can be operated in countercurrent or DC-current 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, first the cooling fluid flowing tangentially to the roller decreases

Heat up and is then redirected 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, a correspondingly different specific coolant flow rate results for the narrow cooling shells and thus different cooling of the work roll per cooling shell. Depending on the design, a barrier cooling liquid or a gap seal is inserted between the narrow cooling shells to separate the different coolant flow rates.

For optimum control of the cooling device, a calculation model (process model or level 1 model) is used that 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 decrease, 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 depending on the set coolant admission width, - adjustment of the coolant quantity over the bandwidth by adjusting the outlet openings of the feed channel (parabolic, higher order or zone by zone) and / or adjustment of the gap width between the cooling pan and work roll as a function of bandwidth and / or setting the The position of the widthwise adjustable spray bar sections and / or measured profile and flatness over the bandwidth,

- exchange of signals with the thickness control (scaffolding),

- description of the geometric relationships of the moving parts of the cooling device and consideration of the setting position, fit position and working roll diameter for the purpose of optimal position determination or calculation of changes in position, - Determination of the swivel position of the chilled beam and the position of the chiller shell with the help of the cylinders, if necessary using the pressure and displacement sensor signals, - Control of the calibration procedure for the chiller shell 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.

Show it:

1 shows a spray cooling according to the prior art,

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

3 shows a cooling device according to the invention with a plurality of cooling shell segments, which are articulated to one another, FIG. 4 shows the cooling device of FIG. 3 with alternative cooling liquid flow, FIG. 5 shows a cooling device according to the invention with radially divided one

Kühlschale Fig. 6, the cooling device of FIG. 5 with exchangeable cooling shell or cooling plate,

7 shows a cooling device with cooling-element segments pressed on by springs,

8 shows a cooling device with roll gap cooling / roll gap lubrication and combined low-pressure high-pressure roll cooling, FIG. 9 shows a cooling device with introduced into the cooling shells

Holes, Fig. 10a-f nozzle and cup designs,

11a-c a gap width adjustment, 12 a gap width adjustment,

13 a zone cooling,

14 a gap seal,

15a, b a spatially acting axially adjustable roller cooling,

Fig. 16 bending springs as articulated / elastic connection between adjacent cooling shell segments.

FIG. 1 shows a prior art spray cooling in which a cooling liquid 7 is sprayed by means of nozzles 27 onto 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.

FIG. 2 shows another known possibility for cooling 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 nozzles 27 arranged on the inlet side and through the holes introduced in the concavely curved contiguous cooling shell 11, and a water cushion with a turbulent and undirected 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 coherent flow cooling according to the invention with a coherent cooling shell 11 is shown in FIG. 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 discharge 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, as the diameter of the work-roll 1 changes, the cooling-cup segments 13 can follow the change in curvature of the roll-coated 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-plate segment 13, the cooling-beam support 16 is provided with an articulation point 23, by means of which it is possible to join the cooling-plate segments 13 and all components connected thereto in the illustrated (horizontal, vertical and rotational) adjustment directions 45 of the cooling beam support to move a multi-link linkage, not shown here. 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 the center of the roll or across the width), continuous The roll temperature is measured in order to regulate the size of the gap 30 in order 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 the flow described in FIG. 3 is shown in the cooling device 10 of FIG. The supply pipes 25 for the low-pressure liquid refrigerant ND to be used 7 are here each at the upper and lower cooling cup segment 13, so that here the Kühlflüssigkeitsteilmengen in countercurrent and cocurrent, with respect to the Waizendrehrichtung 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 is compared to the gap width of Fig. 3 enlarged. The adjustment of the individual cooling shells takes place as in FIG. 3 by means of cylinders 20. Instead of cylinders, coil springs can also be used in a simplified manner. In addition to the cooling carried out 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 is shown in FIG. 5. In contrast to FIGS. 3 and 4, in which the cooling shells 11 are 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 here via 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-plate segment 13 forces a flow according to the arrows 43 drawn along the waist-jacket 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 low-pressure high-pressure cooling combined according to the invention 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 figure 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 can 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 using cylinders for adjusting the individual shells as in the previous exemplary embodiments of FIGS. 3 to 6, an alternative solution is disclosed and illustrated in the cooling device 10 of FIG. 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 placed against the work rolls 1, 2 with the aid of a straight or curved cross-bar 48 which can be rotated in a small defined area with a corresponding spring contact pressure of the spring 8. Alternatively, in the area of the cylinders (see FIGS. 3 to 6), coil springs 8 with corresponding holders can be attached to the ends. The gap 30 is determined by spacer plates 49 between the cooling shell 13 and the work roll 1, 2. The material for the spacer plates is 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, depending on however, the section-wise flow cooling system 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, a low-pressure

Flow cooling with integrated roll gap lubrication 19 and roll gap cooling 18 arranged on the inlet side. At the same time, it is disclosed in FIG. 8 how different high-pressure and low-pressure systems can be combined with one another. 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 chilled beams with a rectangular nozzle, it is also possible, according to the cooling device 10 of FIG. 9, to carry out the three chilled beams with interchangeable cooling shells 47, into which many staggered holes 52 are bored, from which individual coolant jets are blown against them from a short distance 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.

Further details on the nozzle and shell design can be taken from FIGS. 10a to 10f, wherein the arrangement of the nozzle takes place in the center of the bowl or, alternatively, in an asymmetric arrangement with a shell, which is shortened on one side, for example. 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. The cooling shell may additionally be provided on the side facing the rollers smoothly or with grooves or webs 9 in order to positively influence the cooling effect by causing turbulences shown: Fig. 10a shows a symmetrical arrangement of the lower part of the cooling beam 54 on the cooling shell 11, 12 with replaceable nozzle 27, Fig. 10b coolant exit from the nozzle 27 with angle α oblique to the roller, Fig. 10c nozzle 27 with alternative cross-sectional shape and possible embodiments of Webs or grooves 9,

Fig. 10d asymmetrically 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 length of the cooling beam with a gap width adjustment in the cooling liquid supply channel 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, bendable spring plates 53 are arranged inside the funnel-shaped feed channel 55 in accordance with the example of FIGS. 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 only represents the principle. Other constructions with the same effect are also possible.

Details for an exemplary embodiment of the gap adjustment in the feed channel 55 are shown in FIGS. 11a to 11c in a side view and in FIG. 12 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, a system operated with air pressure or liquid pressure is provided for the exemplary embodiment in FIG. 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 rotatable 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 exemplary embodiment of FIGS. 11a to 11c, a pressure chamber 56 is arranged laterally on the feed channel 55 as the closure member, the expandable plastic tube 60 of which forms part of the feed channel 55. In the initial state of FIG. 11a, the air chamber 56 is in the pressureless state, so that, as shown in FIG. 12 at the width section 59a, the flow opening b is fully opened. In 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 shown in Figure 12 at the width section 59b. A completely closed flow opening b is shown in FIG. 12 at the width section 59c. Here, according to FIG. 11 c, the pressure chamber 56 has been completely filled and thus the supply channel 55 is shut off 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 mode of operation of the zone cooling is shown in FIG. 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. Through different gap widths and a different loading of the gaps 31, 32, 33 with pressure and volume flow of the cooling liquid, it is thus possible to produce a different specific cooling liquid flow 41 per unit time over the roll 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.

FIG. 14 illustrates a possibility for sealing the gap 30 formed between the work roll 1 and the cooling shell 14 at its edges. Via a tube 25 and a nozzle 27, a fluid jet 28, for example wise air or coolant, selectively blown 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 spatially acting, axially adjustable work roll spray cooling, which can be designed as high-pressure or low-pressure cooling, is shown in 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. 15 a, the spray nozzle bar sections 40 'are moved on a guide rod 63 for this purpose. The positioning of the two spray nozzle bar sections 40 'takes place here symmetrically to the rollers center with the aid of a hydraulic cylinder 61, link rods 62 and nozzle beam support 64. Alternatively, two hydraulic cylinders 61 are conceivable that position both sides 65 individually. A similar arrangement of a locally acting work roll cooling is shown in FIG. 15b. Here, with a hydraulic cylinder 61, articulated rods and articulated arms 62 with spray jet bar sections 40 'mounted thereon are connected via a pivot point 66 a circular path 64 moves and so the cooling jet 7 directed to different positions within or adjacent to the belt 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 stock

5 roller rotation direction

6 roll shell surface

7 coolant

8 spring

9 grooves or bars

10 cooling device

11 contiguous cooling shell

12 radially divided cooling shell

13 cooling shell segments

14 narrow cooling shells

15 pivot point of the cooling shell

16 cooling beam supports

17 scrapers

18 Roll nip cooling

19 Rolling gap lubrication

20 cylinders

21 Fulcrum of the cylinders

22 Joint pivot point of the cooling shell segments

23 articulation point of the cooling beam carrier

24 outlet opening

25 feed tube

26 discharge pipe

27 nozzle

28 fluid jet

29 entrance 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 gauges

37 Sensor for distance measurement

38 temperature sensor

39 odometer

40 spray nozzle beams for high pressure cooling

40 'spray bar section

41 specific coolant flow per unit time

42 barrier cooling liquid for separating the cooling-plate strips

43 Flow direction of the cooling liquid

44 funnel-shaped dispensing slot

45 possible adjustment directions of the cooling beam support

46 contact surface

47 exchangeable cooling plate

48 crossbeams

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 cylinders

62 linkage rods 63 guide rod

64 trajectory

65 movable nozzle beam support

66 fulcrum b flow opening

ND coolant inlet Low pressure cooling

HD Coolant inlet High-pressure cooling s1-s3 Cooling area of cooling shell segments

Claims

claims

Anspruch [en] A method of cooling the rolls (1, 2) of a rolling stand with a low-pressure cooling, in which the rolls are subjected to a low-pressure cooling liquid; characterized in that the rollers are simultaneously subjected to the low-pressure cooling and high-pressure cooling, wherein the rollers are sprayed in the high-pressure cooling directly with a high pressure cooling liquid.

2. The method according to claim 1, characterized in that the low-pressure coolant and the high-pressure coolant are formed materially similar.

3. The method of claim 1 or 2, characterized in that about 20% of the total amount of cooling liquid of the high pressure cooling and about 80% of the total amount of cooling liquid of the main cooling effect generating low pressure cooling are supplied.

4. The method according to any one of the preceding claims, characterized in that depending on the rolling parameters thickness reduction, specific surface pressure in the nip, rolling speed, strip temperature, rolled material and rolled material for the low pressure roll cooling preferably a pressure range for the cooling liquid (7) between 0.5 to < 5 bar and for the high pressure roller cooling a pressure range for the cooling liquid (7) between 5 - 50 bar, preferably 12 bar, is set by means of a process model.

5. The method according to any one of the preceding claims, characterized in that the low-pressure cooling is formed as low-pressure spray cooling, as low-pressure cooling curtain or low-pressure flow cooling, as highly turbulent low-pressure cooling (corresponding to Figure 2), or in the form of a combination of said types of cooling in which, in the case of the low-pressure flow cooling, the cooling liquid is disposed in a gap (30, 31,

32, 33) flows between the roll surface and at least one cooling shell segment which faces a partial region of the roll surface.

6. The method according to claim 5, characterized in that an adjustment of the position of the cooling shell segment (13) to the respective roll diameter and / or roll positions to produce a reproducible cooling effect.

7. The method according to any one of claims 5 or 6, characterized in that in the low-pressure flow cooling, a continuous flow cooling is used, in which the cooling liquid (7) covered by a plurality of cooling shell segments larger contiguous angular range of the roll surface (6) of the roller ( 1, 2), based on the direction of rotation (5) of the roller (1, 2) is supplied in countercurrent and / or in direct current.

8. The method according to any one of claims 5 or 6, characterized in that in the low-pressure flow cooling, a section-wise flow kung is used, in which the cooling liquid (7) in the cooling of the individual cooling shell segments (13) formed cooling regions (44) guided against the rollers (1, 2) and deflected in each case to both sides or primarily in one direction, preferably directed against the roller rotation direction, wherein the corresponding cooling-cup segment (13) forces a flow along each roller (1, 2).

9. The method according to any one of the preceding claims 5 to 8, characterized in that by the cooling shells (13) primarily a coolant flow (43) tangentially along the roll surface (1, 2) is generated or by means of tangential in the tangential spacing plates or Distance bars (49) optionally a coolant flow or coolant outflow is preferably carried out to the side to heat the roller area at the edges next to the band area in the middle of the warm coolant (7).

10. The method according to claim 9, characterized in that in a preferably parallel to the roll axis outflow of coolant, the coolant supply in addition to the band area by the features of zone cooling, for example, the cooling shell distance to the roller (1, 2) and the Kühlmittelzuführkanal (55), is shut off.

11. The method according to any one of the preceding claims, characterized in that the combined low-pressure high-pressure cooling is used for part of the rolling stands, for example, the front stands of a multi-stand hot strip mill, while in the other stands, a pure low-pressure roll cooling is used.

12. The method according to any one of the preceding claims, characterized in that the cooling intensity of the low-pressure cooling, in particular in the low-pressure cooling curtain or the flow cooling, is set differently over the roll length.

13. The method according to claim 12, characterized in that in the Kühlmittelzuführkanal (55) is provided a zone-wise closing of the outlet opening for the coolant over the cooling beam length.

14. The method according to claim 13, characterized in that the outlet opening of the Kühlmittelzuführkanals (55) over the cooling beam length under- has a wide variety and / or can be adjusted continuously.

15. The method according to any one of the preceding claims, characterized in that the distance between the roller surface (6) and a cooling shell (12, 47) over the width of the cooling shell (12, 47) is formed differently and / or continuously over the width of the cooling shell

(12, 47) can be adjusted.

16. The method according to any one of the preceding claims, characterized in that the optionally movable in the width direction Spritzdüsenbal- ken of the high pressure cooling system are used for zone cooling and axially by means of electric or hydraulic motors with threaded rods or by hydraulically moving single or multi-link linkage (62). with spray nozzle bar portion (40 ') or rotatable nozzle units mounted thereon for directing the cooling liquid (7) with directed jet onto the desired area of the roll (1, 2).

17. The method according to any one of the preceding claims, characterized in that the low-pressure flow cooling is performed with the axially in the width direction preferably symmetrical adjustable cooling shell segments to produce a zone cooling effect.

18. The method according to any one of the preceding claims, characterized in that a plurality of cooling shell segments (14) in a narrow embodiment with optionally differently set gap distance (31, 32, 33) to the roll surface and with optionally different specific

Coolant flow (41) are arranged side by side over the roller length to perform a zone cooling over the roller length per unit time.

19. The method according to claim 18, characterized in that for the separation of the different cooling liquid flows (41) of the columns (31, 32, 33) from each other between the cooling shells (14) a barrier cooling liquid (42) is introduced.

20. The method according to any one of the preceding claims, characterized in that a calculation model (process model, level 1 model) is used, which fulfills the following tasks:

Adjustment of the coolant quantity and pressure level for the low-pressure and high-pressure parts depending on strip thickness decrease, 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 application width,

Adjusting the coolant quantity over the belt width by adjusting the outlet openings of the feed channel (parabolic, other curve or zone-wise) or / and adjusting the gap width between the cooling shell and

Roller as a function of the bandwidth and / or adjustment of the position of the widthwise adjustable spray bar sections and / or measured profile and flatness state over the bandwidth, exchange of signals with the thickness control (scaffolding), description of the geometric relationships of the moving parts of the cooling device as well as consideration of Adjustment position, passline position and roll diameter for optimum position determination or calculation of the position changes, and determination of the pivoting position of cooling beam support and Kühlschalenanstellposition using the cylinder, if necessary, using the pressure and displacement sensor signals.

I. method according to claim 20, characterized in that for adjusting the exact position of the cooling beam support (16) and the Kühlschalenseg- elements (13) in front of the roll surface (6) performed a calibration process becomes.

22. The method according to any one of the preceding claims, characterized in that the temperature of the roller, in particular the roller surface, and / or the temperature of the coolant is controlled in the context of a temperature control, wherein one or more actual or measured values of one or a plurality of temperature sensors (38) on the roller and / or of temperature measurements of the coolant in the coolant supply and / or the coolant discharge with predetermined temperature setpoints are compared and to compensate for any detected deviation between the set and actual temperatures see a setting of the distance

Cooling shells or the cooling shell segments (13) from the roll surface (6) and / or the opening width of the outlet opening (24, b) takes place in accordance with the size of the control deviation.

23. The method according to any one of the preceding claims, characterized in that it is the cooling liquid of the high pressure cooling system and the low pressure cooling system, for example, an emulsion, a Disperson, kerosene or water, is.

24. A 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 upon by a low-pressure cooling liquid; characterized in that in addition to the low-pressure cooling system and a high-pressure cooling system is provided which is equipped with spray pipes and nozzles for direct spraying of the rollers with the high pressure coolant at the same time to the low pressure cooling by the low pressure cooling system.

25. Cooling device according to claim 24, characterized in that the low-pressure cooling system is designed to produce a low pressure Spray cooling, a low pressure cooling curtain or a low pressure

Stream cooling, or a highly turbulent low pressure cooling, or a combination of the aforementioned types of cooling.

26. Cooling device according to claim 25, characterized in that the low-pressure cooling system for generating the low-pressure flow cooling has at least one cooling shell (11) with at least one preferably arcuate cooling shell segment (13, 52), which is connected to the surface of the roll to be cooled (1 , 2) forms a gap (20) which can be filled with the flowing cooling liquid (7), which gap is preferably adjustable with regard to its gap width in the form of the distance between the roll surface and the cooling shell.

27. Cooling device according to claim 24 to 26, characterized in that the high pressure cooling system has a single or multi-row spray nozzle bar (40, 40 ') with the nozzles for high pressure cooling of the rolls.

28. Cooling device (10) according to claim 27, characterized in that a cooling beam support (16), which is fastened to one, preferably the middle of the cooling shell segments, and all components which are connected to the cooling beam carrier, for example via adjusting elements, in particular adjacent cooling shell segments or the spray nozzle beam, in the direction of arrow (45) horizontally, vertically and rotationally movable.

29. Cooling device according to one of claims 24 to 28, characterized in that in the combined low-pressure high-pressure cooling system, the spray nozzle bars (40, 40 ') of the high pressure cooling system above and / or below and / or within the low pressure cooling system fixed or in the width direction are movably arranged.

30. A cooling device according to any one of claims 24 to 29, characterized in that two or more of the cooling-cup segments are movably associated with each other. connected to other.

31. Cooling device according to one of claims 24 to 30, characterized in that the movable connection between the cooling-shell segments in the form of a rotary joint and / or a spring and / or an elastic connection and / or a multi-link Gelenkgetriebean- order executed.

32. Cooling device (10) according to claim 30 or 31, characterized in that the arcuate individual cooling-cup segments (13) preferably have laterally or at their ends joints or joint halves which, connected to one another, have a corresponding number of pivot pivots or articulation points (22, 15) form; and that the individual cooling-plate segments (11, 52) each have an articulation point in the form of a pivot point (21), wherein the pivot points of the individual cooling-shell segments are interconnected by at least one adjustment element (20) which is variable in its length.

33. Cooling device (10) according to claim 32, characterized in that the adjusting element is provided with a displacement measuring system and / or pressure transducers.

34. Cooling device (10) according to any one of claims 32 or 33, characterized in that the cooling shell segments (13) can be tilted individually to each other by the adjusting element (20), so that an adaptation to the respective roll diameter is possible.

35. Cooling device (10) according to one of claims 32 to 34, characterized in that the adjusting element (20) in the form of a cylinder, for example a hydraulic or pneumatic cylinder, or in the form of a rod is formed whose length, taking into account the roll diameter range of manually or for example by means of a hydraulic system. Raulik- or electric motor is suitably adjustable.

36. Cooling device (10) according to one or more of claims 28 to 35, characterized in that at least one of the cooling shell segments (13, 52), e.g. the middle, by the cooling beam support (16) in front of the roller (1, 2) is positionable and the other cooling shell segments (13, 52) spaced by spacer plates (49) via springs (8) against the roller (1, 2) can be pressed.

37. Cooling device (10) according to one or more of claims 24 to 36, characterized in that the cooling shell or the cooling-plate segment (13) has a quasi-rectangular nozzle or outlet opening (24) and / or holes or bores (52). in the cooling shell, from which the cooling liquid (7) flows against the roll (1, 2).

38. Cooling device (10) according to claim 37, characterized in that

Mouthpieces of the nozzle or outlet openings (24) and / or cooling shell plates (47) are made exchangeable.

39. Cooling device (10) according to one or more of claims 24 to 38, characterized in that the cooling-plate segments (47) of a flow-cooling region are divided into two, so that by relative displacement and subsequent fixing of the two halves the nozzle or outlet opening (24). and thus the amount of coolant is easily adjustable.

40. Cooling device (10) according to one or more of claims 24 to 39, characterized in that by means of a sealing function or a sealing means by a predetermined pressure against the rollers (1, 2) a space between the cooling shells (11, 12) or the cooling-plate segments (13) and the roll surfaces (1, 2) is formed from the little coolant (7) passes into the environment.

41. Cooling device (10) according to one or more of claims 24 to 40, characterized in that the cooling shells (11, 12) of a plurality, in the roll longitudinal direction juxtaposed spaced narrow cooling shells (14) or cooling shell segments (13) are formed, the with different columns (31, 32, 33) and as a result of different specific coolant flow (41) can be acted upon per unit time.

42. Cooling device (10) according to one of claims 24 to 41, characterized in that the nozzles of the high-pressure cooling system are designed as flat jet nozzles.

43. Cooling device (10) according to one of claims 24 to 42, characterized in that the high-pressure cooling system is arranged on the scaffold outlet side.

44. Cooling device (10) according to any one of claims 24 to 43, characterized in that it is in the rolls of the rolling mill to the work rolls.