DEVICE AND METHOD FOR COOLING A ROLL

Abstract

The invention relates to a device and a method for cooling a roll. The roll concerned can be a roller in a roll stand or a measuring roll. The device comprises a cooling shell having a cross section in the shape of a section of a circular arc, for covering a surface region of the roll (200), wherein, in the region of an edge of the cooling shell, a bearing is formed with a pivot joint (120) with an axis of rotation running perpendicular to the circular arc-shaped cross-section, for pivoting the cooling shell about the axis of rotation. According to the invention, in order to ensure that the size of the cooling gap during the rolling operation or during the operation of a measuring roll is always autonomously optimally set, the bearing has a degree of freedom in radial direction r with respect to the circular arc-shaped cross-section of the cooling shell, such that the cooling shell is mounted in the bearing in such a way as to be freely movable in the radial direction.

Claims

1. Device (100) for cooling a roll (200), comprising: a cooling shell (110) with a cross section in form of a section of a circular arc for covering a surface region of the roll (200), wherein in a region of an edge of the cooling shell a bearing is formed with a pivot joint (120) with an axis of rotation (122) running perpendicular to the circular arc-shaped cross section for pivoting the cooling shell (110) about the axis of rotation; characterized in that the bearing (120) has a degree of freedom in a radial direction (r) with respect to the circular arc-shaped cross section of the cooling shell (110), so that the cooling shell is mounted in the bearing (120) in such a way as to be freely movable in the radial direction (r).

2. Device (100) according to claim 1, characterized in that the cooling shell (110) is hung freely swinging from the pivot joint of the bearing (120).

3. Device (100) according to claim 1, characterized in that a ballast weight (112) is mounted on a convex curved outside of the cooling shell (110)—also at a spacing from the outside of the cooling shell by means of a lever aim (114).

4. Device according to claim 3, characterized in that the lever arm (114) and the ballast weight (112) are designed and arranged so that a desired torque about the axis of rotation (122) of the pivot joint is adjusted in concert with weight distribution of the cooling shell (110) for a predetermined deflection of a combination of cooling shells and ballast weight from a pendulum position of rest.

5. Device (100) according to claim 1, characterized by a nozzle mechanism (130) for spraying a cooling medium (400) with a predetermined pressure or volume flow substantially tangentially to a concave curved inside of the cooling shell (110).

6. Device (100) according to claim 1, characterized by a positioning mechanism (140), which engages with the bearing (120) for positioning of the bearing with the radially movable cooling shell (110) mounted thereon in a predetermined position (α).

7. Device (100) according to claim 1, characterized in that the bearing (120) is designed as a spherical bearing.

8. Rolling stand comprising: at least one roll (200) for rolling of a rolled product (300); and a device (100) for cooling the at least one roll and having a cooling shell (110) with a cross section in form of a section of a circular arc for covering a surface region of the roll (200), wherein in a region of an edge of the cooling shell, a bearing is formed with a pivot joint (120) with an axis of rotation (122) running perpendicular to the circular arc-shaped cross section for pivoting the cooling shell (110) about the axis of rotation, and characterized in that the bearing (120) has a degree of freedom in a radial direction (r) with respect to the circular arc-shaped cross section of the cooling shell (110), so that the cooling shell is mounted in the bearing (120) in such a way as to be freely movable in the radial direction (r), wherein the cooling shell (110) is positioned on a circumference of the roll (200) and mounted in the bearing (120) free to move in the radial direction (r).

9. Rolling stand according to claim 8, characterized in that the device (100) is mounted free swinging on the circumference of the roll (200) in the pivot joint of the single bearing (120).

10. Rolling stand according to claim 8, characterized in that the device (100) is mounted with the of a positioning mechanism (140) at an angle position α of the axis of rotation (122) of the pivot joint (120) in a circumferential direction (U).

11. Rolling stand according to claim 8, characterized in that the bearing (120) on which the cooling device is hung free swinging is mounted on the rolling stand.

12. Rolling stand according to claim 8, characterized in that the bearing (120) on which the device (100) is hung free swinging, is designed in form of two halves which are mounted on chocks of the roll.

13. Measurement device with: a roll in the form of a measuring roller, on whose surface are arranged sensors for detecting of a pressure or planarity distribution in width direction of a rolled product which is partly wrapped around the measuring roller; and a device (100) for cooling a roll (200), and having a cooling shell (110) with a cross section in form of a section of a circular arc for covering a surface region of the roll (200), wherein in a region of an edge of the cooling shell a bearing is formed with a pivot joint (120) with an axis of rotation (122) running perpendicular to the circular arc-shaped cross section for pivoting the cooling shell (110) about the axis of rotation and characterized in that the bearing (120) has a degree of freedom in a radial direction (r) with respect to the circular arc-shaped cross section of the cooling shell (110), so that the cooling shell is mounted in the bearing (120) in such a way as to be freely movable in the radial direction (r), and wherein the cooling shell (110) is positioned on a circumference of the roll (200) and mounted in the bearing (120) free to move in the radial direction (r).

14. Measurement device according to claim 13, characterized in that the device (100) is mounted free swinging on the circumference of the measuring roller (200) in the pivot joint of the single bearing (120).

15. Measurement device according to claim 13, characterized in that the device (100) is mounted with the help of the positioning mechanism (140) at an angle position α of the axis of rotation (122) of the pivot joint (120) in the circumferential direction (U).

16. Measurement device according to claim 13, characterized in that the bearing (120) on which the device (100) is hung free swinging is designed in form of two halves which are mounted on chocks of the roll.

17. Method of operating, in a rolling operation, a rolling stand having at least one roll (200) for rolling of a rolled product (300); and a device (100) for cooling the at least one roll and having a cooling shell (110) with a cross section in the form of a section of a circular arc for covering a surface region of the roll (200), wherein in a region of an edge of the cooling shell, a bearing is formed with a pivot joint (120) with an axis of rotation (122) running perpendicular to the circular arc-shaped cross section for pivoting the cooling shell (110) about the axis of rotation, and characterized in that the bearing (120) has a degree of freedom in a radial direction (r) with respect to the circular arc-shaped cross section of the cooling shell (110), so that the cooling shell is mounted in the bearing (120) in such a way as to be freely movable in the radial direction (r), wherein the cooling shell (110) is positioned on the a circumference of the roll (200) and mounted in the bearing (120) free to move in the radial direction (r), or for operating a measurement device having a roll in the form of a measuring roller, on whose surface are arranged sensors, for example pressure sensors, for the detecting of a pressure or planarity distribution in the breadth direction of a rolled produce which is partly wrapped around the measuring roller; and a device (100) for cooling a roll (200), and having a cooling shell (110) with a cross section in form of a section of a circular arc for covering a surface region of the roll (200), wherein in a region of an edge of the cooling shell a bearing is formed with a pivot joint (120) with an axis of rotation (122) running perpendicular to the circular arc-shaped cross section for pivoting the cooling shell (110) about the axis of rotation; and characterized in that the bearing (120) has a degree of freedom in a radial direction (r) with respect to the circular arc-shaped cross section of the cooling shell (110), so that the cooling shell is mounted in the bearing (120) in such a way as to be freely movable in the radial direction (r), and wherein the cooling shell (110) is positioned on a circumference of the roll (200) and mounted in the bearing (120) free to move in the radial direction (r), the method comprising the following steps: pre-positioning of the device in an angle position α on a circumference of the roll and at a predetermined radial spacing from the roll; spraying of a cooling medium with a predetermined pressure or volume flow into a cooling gap between outside of the roll and a concave curved inside of the cooling shell; and turning of the roll for the rolling of a rolled product during the rolling operation or for transporting of the rolled product during the operation of the measuring roller; and during spraying of a cooling medium, releasing of the device in the radial direction (r), so that a size (h) of a cooling gap suitably adjusts itself in the region of the pivot joint (120) on account of the free mobility of the cooling shell (110) there in the radial direction in dependence on the magnitude of the pressure or the volume flow of the cooling medium sprayed into the cooling gap.

18. Method according to claim 17, characterized in that the size (h) of the cooling gap is suitably adjusted over the entire cooling shell in the sense of an equilibrium of forces between a radially inwardly acting distribution of pendulum force of the cooling shell, a likewise radially inwardly acting distribution of a suction force of the flow of cooling agent in the cooling gap, and a distribution of a force of reaction of the cooling medium.

Description

[0021] There are 5 Figures enclosed with the specification, where

[0022] FIG. 1 is a cross section through the device according to the invention and the rolling stand according to the invention;

[0023] FIG. 2 is a supplement to FIG. 1;

[0024] FIG. 3 is another sample embodiment for the placement of the cooling shell according to the invention on the circumference of a roll;

[0025] FIG. 4 is a first embodiment of the single bearing for the cooling shell; and

[0026] FIG. 5 is a second embodiment of the single bearing for the cooling shell.

[0027] The invention shall now be described in detail in the form of sample embodiments, making reference to the mentioned figures. In all figures, identical technical elements are designated with the same reference numbers.

[0028] FIG. 1 shows a cross section through the rolling stand according to the invention. Of the rolling stand only one roll is seen in the form of a rolling roll 200 for the rolling of rolled product 300. The roll turns in the direction of rotation D. The roll is matched up on its right side with a device 100 according to the invention. Specifically, the device 100 comprises a cooling shell with a cross section in the shape of a circular arc section for the covering of a surface region of the roll 200. In the region of the upper edge of the cooling shell 110 there is arranged a bearing 120 with a pivot joint. The bearing is designed so that its axis of rotation 122 runs perpendicular to the circular cross section of the cooling shell 110 and parallel to the axis of rotation A of the roll 200. At this single pivot joint 120, the cooling shell 110 is hung free swinging. The single bearing with the pivot joint in which the cooling shell is rotationally mounted has a degree of freedom in the radial direction r with respect to the circular cross section of the cooling shell or with respect to the axis of rotation A of the roll 200, so that the cooling shell is mounted in the bearing 120 free to move in the radial direction r. Accordingly, the bearing is designed not only as a pivot joint, but also as a sliding bearing.

[0029] FIG. 4 shows a first embodiment for the single bearing 120 of the cooling shell, wherein it consists of two half bearings 120-1, 120-2, each of them secured to one of the chocks, i.e., one of the bearing housings 210-1, 210-2 of the roll 200. While this has the drawback that the weight distribution over the center axis A of the complete roll 200 is not in equilibrium, nevertheless the roll according to the invention does not become stripped, since the half bearings need not transmit any bending moment, but only be able to adjust themselves freely.

[0030] FIG. 5 shows a second embodiment for the single bearing 120, where the bearing is arranged centrally on the cooling shell 110. The bearing is mounted or hung with the aid of a positioning mechanism 140, such as one in the form of an articulated arm or pivot arm 141, for example on a cross member of the rolling stand, centrally to the roll 200.

[0031] When the bearing 120 or the half bearings have a spherical design, the axis of rotation of the bearing or the cooling shell 110 in both embodiments can follow a skewing of the roll, so that in this case as well the axis of rotation of the cooling shell remains parallel with the axis of rotation of the roll. The swivel motion or deflection of the bearing required for this is indicated by an arc-shaped double arrow in FIGS. 4 and 5.

[0032] The bearing or the pivot joint in both embodiments can be positioned at any given angle position α on the circumference U of the roll.

[0033] Either on the upper edge of the cooling shell, as shown in FIG. 1, or on the lower edge of the cooling shell 110 there is provided a nozzle mechanism for the spraying of a cooling medium 400 into a cooling gap between the inside of the cooling shell 110 and the lateral surface of the roll 200. The side or edge of the cooling shell 110 at which the nozzle mechanism 130 supplies the cooling medium 400 to the cooling gap depends on the direction of rotation D of the roll and whether a counterflow cooling or a concurrent flow cooling is desired; in the latter case, the cooling medium 400 flows in the circumferential direction and direction of rotation D of the roll 200.

[0034] At the edge of the cooling shell opposite the supply of cooling medium, the shell preferably has no boundary of any kind, especially no collecting tank for the cooling medium, so that an unhindered force-free drainage of the cooling medium is assured there. This is advantageous for the free play of forces mentioned in the next paragraph.

[0035] The cooling medium 400 is forced by the nozzle mechanism 130 either with a given volume flow V.sub.strom or a given pressure P into the cooling gap. Thanks to the pivot joint 120 which is mounted freely movable in the radial direction, under a free play of forces the height h of the cooling gap 160 optimally adjusts itself automatically or spontaneously. Thanks to the free swinging suspension of the cooling shell in the pivot joint 120, the height h of the cooling gap automatically or spontaneously adjusts itself correctly not only at the height of the pivot joint, but also everywhere in the angle range β of the cooling shell. This makes unnecessary a manual or automatic setting of a fixed height h.

[0036] The adjusted height h of the cooling gap, as noted, is dependent on the free play of forces. Specifically, the gap height is influenced by the following physical quantities: the volume flow or the pressure of the cooling medium 400 in the cooling gap and the torque or the resulting area loading, which the cooling shell, optionally with ballast weights secured to it, exerts on the cooling medium during rolling operation when deflected about the axis of rotation 122 of the pivot joint 120. In mathematical terms, the following relation holds:

h=f[[1/(m*g);]/C;{dot over (V)}.sub.Strom;P]  (1)

[0037] where we have: [0038] h: gap height [0039] f: functional relationship [0040] m: overall weight of the cooling shell with ballast weights or corresponding weight distribution [0041] g: gravitational constant [0042] C: lever arm of the cooling shell when deflected from the pendulum position of rest [0043] V.sub.strom volume flow of the cooling medium [0044] P: pressure of the cooling medium

[0045] The torque of the cooling shell 110 with the ballast weights 112 depends on the distribution of the ballast weights 112 on the convex outer circumference of the cooling shell 110 and their spacing from the convex outside of the cooling shell 110. The greater the ballast weights and the further away from the outside of the cooling shell 110 they are, the greater is the torque and thus also the force or the area load with which the cooling shell presses on the roll or the cooling medium 400 in the cooling gap; this relationship is shown graphically in FIG. 2. The broken lines symbolize the greater force or torque action with the loading weights 112 placed further on the outside as compared to ballast weights lying further on the inside (nonbroken lines).

[0046] Ideally the bearing 120 is designed as a sliding bearing with a pivot joint able to move freely therein in the radial direction for the free swinging suspension of the cooling shell. In this ideal type of bearing system, the positioning of the bearing in a definite angle position α on the periphery of the roll would be fixed.

[0047] In practice, it is generally sufficient for the positioning of the roll in the circumferential direction U to be only approximately constant; that is, slight fluctuations in the angle position are generally tolerable. Under this precondition, the bearing 120 can be realized such that the pivot joint is secured to the positioning mechanism 140, which can swivel in a plane transverse to the axis of rotation of the roll 200. Of the positioning mechanism, only a lever 141 is shown in FIG. 1, at the end of which the pivot joint 120 is arranged, and whose other end is mounted, e.g., at a fixed pivot point. The positioning mechanism 140 so designed then constrains the pivot joint 120 in an orbit with at least one component in the radial direction of the roll 200. In this radial direction, the pivot joint must be freely movable at least during the rolling operation, if necessary also tolerating slight fluctuations in the angle position α. Accordingly, the swiveling positioning mechanism 140 in the described embodiment ensures the degree of freedom of the bearing 120 in the radial direction. The positioning mechanism 140 can have a drive unit, not shown in FIG. 1, for the positioning of the pivot joint in a starting position before and at the end of the cooling operation. This drive unit may be mechanical, electromechanical, pneumatic or hydraulic. The drive unit may be arranged either inside or outside the rolling stand. In the starting position, however—not later than the start of the rolling and cooling operation—the free radial mobility must be assured or allowed.

[0048] The curvature of the cooling shell 110 preferably corresponds to the curvature of the roll 200, so that the center axis of the curved cooling shell 110 preferably coincides with the axis of rotation of the roll 200, as shown in FIG. 1 by the broken lines and the angle β.

[0049] Furthermore, a stripper 150 is arranged in FIG. 1 between the lower end of the cooling shell 110 and the rolling product 300. This stripper 150 protects the structural parts above it, i.e., in particular the cooling device 100 according to the invention, against influences from the rolled product 300. Furthermore, the stripper ensures that the rolled product 300 is diverted from the roll 200 and moved further in the rolling direction WR.

[0050] Alternatively to the design of the roll as a roller in a rolling stand, the roll can also be designed as a measuring roller, on whose surface surfaces are then arranged, typically pressure sensors. Such a measuring roller can be mounted for example in a roller conveyor behind a rolling train. During the operation, the measuring roller may be partly wrapped around with hot rolled product, so that the sensors might be heated too intensely. The device according to the invention can then be positioned on the circumference of the measuring roller for a cooling of the sensors. In this way, a temperature range can be established on the sensors which does not harm the sensors.

[0051] The cooling device according to the invention for the cooling of a roll in a rolling stand or for the cooling of a measuring roller works as follows:

[0052] During the rolling operation or the operation of the measuring roller, the cooling medium 400 is supplied by means of the nozzle mechanism 130 with a predetermined pressure P or a predetermined volume flow V.sub.strom, as shown in FIG. 1, to the cooling gap 160. Thanks to the mounting of the cooling shell 110 on the pivot joint 120 with free mobility in the radial direction r, the height h of the cooling gap is then optimally established not only in the region of the pivot joint 120, but also over the entire angle range 13 of the cooling shell 110. Optimal means according to the free play of forces and torques. Particularly involved in this free play of forces is the force distribution in the angle range R, acting from the cooling shell 110 on the cooling medium in the cooling gap, as shown in FIG. 2. The magnitude of this force distribution, as noted, is dependent on the weight distribution of the cooling shell itself and—if present—the size of the ballast weights 112, their distribution at the outer circumference of the cooling shell 110 and their distance from the outside of the cooling shell. The magnitude of the resulting torque also depends on the angle position α of the axis of rotation of the pivot joint 120 at the circumference of the roll, since this determines the size of the lever arm C, which [missing verb: determines?] the distance between the centroid line of the cooling shell 110, which this is hung free swinging from the pivot joint 120 (left dash-and-dot line in FIGS. 1 and 2) and under deflection of the loaded cooling shell due to the roll 200 and the cooling medium 400 in the cooling gap; see right dash-and-dot line in FIGS. 1 and 2. The size of the lever arm C is substantially influenced by the position of the pivot joint 120 on the circumference of the roll 200.

[0053] The mentioned radial forces on account of the torque of the cooling shell 110 act at the center point or at the axis of rotation of the roller or roll 200. Likewise, the cooling shell 110 is also pulled by the cooling medium 400 flowing in the cooling gap 160 toward the axis of rotation of the roller or roll, because a partial vacuum prevails in the cooling gap on account of the flowing medium 400. The two mentioned force distributions pointing toward the axis of rotation of the roller or roll are compensated entirely by a reaction force distribution, which is produced by the cooling medium in the cooling gap, because the cooling medium in the cooling gap essentially cannot be compressed and this must be taken into account by the volume flow or pressure of the cooling medium dictated by the nozzle mechanism 130. Accordingly, the radial reaction force distribution prevents the height of the cooling gap from becoming zero.

[0054] The cooling shell 110 because of the optionally and variably positionable ballast weights possesses an adjustable characteristic in regard to its weight distribution and thus the torque exerted by it. Specifically, the ballast weights 112 are variable in their size and can be positioned freely in their distribution at the convex outside of the cooling shell. The arc dimension 11 can also be chosen suitably. The interplay of the cooling shell's weight distribution characteristic and the volume flow or pressure of the cooling medium 400 dictated by the nozzle device 130 automatically yield a particular size h of the cooling gap 160. The interplay of the described parameters means that the cooling shell 110 thanks to the resulting pressure relations in the cooling gap 160 with its flow of cooling medium brings about a clinging of the cooling shell to the cooling medium 400 or to the roll 200. It becomes clear from equation 1 that the height h of the cooling gap can be influenced by variation of the weight distribution of the ballast weights 112 and the angle position α. Specifically, larger ballast weights and larger torques bring about a higher area load, which must ultimately be borne by the flow of the cooling medium 400 in the cooling gap 160. The volume flow V.sub.strom, or the pressure P of the cooling medium 400 of the nozzle mechanism 130 in process variables should provide to the cooling process predetermined limits of a higher-level control system of the rolling process.

[0055] Specifically, the desired thermal power, represented by the so-called heat transfer coefficient a, is dependent on the height h of the cooling gap 160 and the volume flow of the cooling medium 400 in the cooling gap 160.

[0056] For a given desired cooling power or given heat transfer coefficient a and for pressure or volume flow of the cooling medium furthermore dictated by the nozzle mechanism 130, the required torque of the cooling shell 110 about the axis of rotation 122 can be calculated. Specifically, one then gets the necessary torque as an integral of the pressure distribution of the cooling medium 400 in the cooling gap 160 multiplied by the area of the cooling shell 110 and integrated over the distance to the point of suspension, i.e., to the axis of rotation 122 of the bearing 120.

[0057] The cooling device proposed by the invention offers the advantage that the height h of the cooling gap 160 in the radial direction is optimally established spontaneously and the cooling shell floats on the roller or roll or clings to the roll by virtue of the flow and pressure relations of the cooling medium 400 in the cooling gap. The cooling device operated in this way produces a uniform cooling in the circumferential direction and over the breadth of the roll.

[0058] FIG. 3 shows another sample embodiment for the positioning of the cooling device 100 according to the invention on the circumference of the roll 200.

[0059] Specifically, FIG. 3 shows a sample embodiment of the device 100 according to the invention in which the cooling shell is arranged on the underside of the roll 200 for the cooling of the roll in the region of the quadrants III and IV. Here as well, the pivot bearing 120 is secured to a positioning mechanism 140, which comprises substantially a lever arm 141, which is mounted to swivel about a pivot point 143. The positioning mechanism 140 is designed such that a swiveling of the pivot arm 114 is permitted at least in an angle range γ, making possible a free mobility of the pivot joint 120 in the radial direction r.

[0060] In this sample embodiment as well, the cooling shell 110 is hung free swinging from the pivot bearing 120; however, the ballast weight 112 in the present case is arranged via the lever arm 114 in relation to the axis of rotation 122 of the pivot joint 120 such that the cooling shell 110 on the whole presses with an area load F or a torque M against the underside of the roll 200 and does not fall for example in a centroid line in the direction of the force of gravity, i.e., the pendulum position of rest.

LIST OF REFERENCE NUMBERS

[0061] 100 Device

[0062] 110 Cooling shell

[0063] 112 Ballast weight

[0064] 114 Lever arm

[0065] 120 Bearing, especially pivot joint

[0066] 120-1 Half bearing

[0067] 120-2 Half bearing

[0068] 122 Axis of rotation

[0069] 130 Nozzle mechanism

[0070] 140 Positioning mechanism

[0071] 141 Pivot arm

[0072] 143 Pivot point

[0073] 150 Stripper

[0074] 160 Cooling gap

[0075] 200 Roll, especially a roller

[0076] 210-1 Chock

[0077] 210-2 Chock

[0078] 300 Rolled product, metal strip

[0079] 400 Cooling medium

[0080] h Size/height of the cooling gap

[0081] r Radial direction

[0082] D Direction of rotation

[0083] F Area load

[0084] M Torque

[0085] U Circumferential direction

[0086] A Axis of rotation of the roll

[0087] C Lever arm

[0088] V.sub.strom Volume flow of the cooling medium

[0089] P Pressure of the cooling medium

[0090] a Heat transfer coefficient

[0091] α Angle position

[0092] β Angle range of the cooling shell

[0093] WR Rolling direction

[0094] I, II, III, IV Quadrants of the roll cross section