Device and method for cooling rolled stock

Abstract

A device for cooling rolled stock, preferably for cooling during cold rolling, including a nozzle for applying a cooling medium to the rolled stock, wherein a cooling chamber that is in fluid communication with the nozzle and extends substantially parallel to the strip running plane is provided for applying the cooling medium to the rolled stock.

Claims

1. A device for cooling flat rolled stock, comprising: an outer shroud arranged at only one surface of the flat rolled stock; a nozzle for applying a coolant to the rolled stock; a cooling chamber in fluid communication with the nozzle and extending essentially parallel to a strip passline for applying the coolant to only the one surface of the rolled stock; and an adjusting device for moving the outer shroud substantially parallel to the strip passline and the one surface to reverse a flow direction of the coolant in the cooling chamber, wherein the outer shroud is shiftable from a first position to a second position so that, depending on the position of the outer shroud, two feed lines and two drains are respectively connectable to each other so that the flow direction of the coolant is changed.

2. The device according to claim 1, wherein the cooling chamber is positioned between the rolled stock and a chamber roof.

3. The device according to claim 1, wherein the nozzle is configured so that the coolant is conducted as an essentially uniform flow into the cooling chamber.

4. The device according to claim 1, wherein the cooling chamber is configured so that the coolant flows through the cooling chamber as an essentially uniform flow.

5. The device according to claim 1, wherein the cooling chamber has a cross section that is essentially constant in a strip travel direction.

6. The device according to claim 1, wherein the cooling chamber extends in a direction opposite to a strip travel direction so that the coolant is guided in the direction opposite to the strip travel direction.

7. The device according to claim 6, wherein the nozzle is situated downstream, with respect to the strip travel direction, from the cooling chamber.

8. The device according to claim 1, wherein the nozzle is a slit nozzle.

9. The device according to claim 1, wherein the cooling chamber comprises at least one cooling chamber roof extending parallel to the rolled stock and at least one side wall perpendicular to the rolled stock and extending in the strip travel direction to form a lateral boundary of the cooling chamber.

10. The device according to claim 1, wherein a transition from the nozzle to the cooling chamber comprises a separation edge for the flow of the coolant into the cooling chamber.

11. The device according to claim 1, wherein the cooling chamber has side walls at a distance to the strip width between 2 mm and 100 mm, but never more than 10% relative to the strip width.

12. The device according to claim 11, wherein the distance is between 10 mm and 50 mm.

13. The device according to claim 1, wherein an outlet side of the flow from the cooling chamber comprises a flow brake.

14. The device according to claim 1, further comprising a drainage chamber following the cooling chamber for removing the coolant from the rolled stock.

15. The device according to claim 14, wherein the drainage chamber is larger than the cooling chamber to reduce flow velocity of the coolant in the drainage chamber in comparison to flow velocity in the cooling chamber.

16. The device according to claim 1, wherein a feed of coolant to the nozzle is automatically controllable by a controllable pump unit, and the feed of the coolant is determined as a function of various parameters of the rolled stock.

17. The device according to claim 16, wherein the parameters of the rolled stock include at least one of the group consisting of: temperature of the rolled stock, material of the rolled stock, and residual fluid on the rolled stock after rolled stock passed through the device.

18. The device according to claim 1, wherein at least the cooling chamber is movable away from a plane of the rolled stock to facilitate threading-in of the rolled stock.

19. The device according to claim 1, further comprising at least one device provided outside the cooling chamber for removing excess coolant from the rolled stock.

20. The device according to claim 19, wherein the at least one device for removing excess coolant is an air-blast device, a spray device, a suction device, a transverse air-blast device, or a blower.

21. The device according to claim 1, further comprising at least one device provided outside the cooling chamber for removing excess coolant from the rolled stock, the at least one device includes a deflector plate that collects the coolant removed by air-blasting or spraying and carries the coolant away from a surface of the strip.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 shows a schematic diagram of a rolling train with rolling stands and devices for cooling;

(2) FIG. 2 shows a schematic diagram of a reversing stand with a device for cooling;

(3) FIG. 3 shows a device for cooling rolled stock with a cooling chamber;

(4) FIG. 4 shows the device for cooling according to FIG. 3 with a detailed illustration of the flow relationships;

(5) FIG. 5 shows a comparison between the heat transfer in a device for cooling rolled stock as proposed above and that of a conventional spray cooling system;

(6) FIG. 6 shows a schematic diagram of an especially advantageous embodiment of the transition between nozzle and cooling chamber;

(7) FIG. 7 shows a schematic diagram of a preferred embodiment of the strip cooling system with adjustable side walls for adapting the chamber to the width of the strip;

(8) FIG. 8 shows a schematic diagram of a preferred embodiment of the strip cooling system with a flow brake at the outlet where the flow leaves the cooling chamber;

(9) FIG. 9 shows a schematic diagram of another exemplary embodiment of a device for cooling rolled stock;

(10) FIG. 10 shows a device for cooling rolled stock together with a drainage chamber;

(11) FIG. 11 shows a device for cooling rolled stock with a drainage chamber on both sides of the strip;

(12) FIGS. 12a and 12b show diagrams of a device for cooling a strip with a drainage chamber, which can be adjusted as a function of the strip travel direction;

(13) FIG. 13 shows a schematic diagram of how the cooling device can be opened so that the strip can be threaded in;

(14) FIG. 14 shows another device for cooling rolled stock with removal devices on both sides serving a barrier function and with a deflector plate; and

(15) FIG. 15 shows a schematic diagram of a control unit together with the device for cooling rolled stock.

DETAILED DESCRIPTION OF THE INVENTION

(16) In the following, preferred exemplary embodiments are described on the basis of the figures. Elements which are the same or similar or which function in the same or a similar way are designated by the same reference numbers, and in some cases the description of these elements is not repeated to avoid redundancies in the description.

(17) FIG. 1 shows a schematic diagram of a rolling train with several rolling stands 1, by means of which the rolled stock 2 is rolled thinner. Schematically illustrated cooling devices 3 for cooling the rolled stock 2 are located in front of the first stand, behind the last stand, and between the stands.

(18) FIG. 2 shows another rolling train, in this case with a reversing stand 1, also shown schematically, in front of and behind which are cooling devices 3 for cooling the rolled stock 2.

(19) It is immediately clear from FIGS. 1 and 2 that the cooling device 3 can be arranged at any desired point, i.e., in front of the rolling stand 1 in question, between rolling stands, or behind the rolling stand in question. There is therefore a corresponding freedom with respect to the arrangement of the cooling devices 3, which can be placed wherever they best serve the purpose of the specific rolling process in question.

(20) FIG. 3 shows a schematic diagram of a cooling device 3, which is supplied with coolant through a feed line 30. The feed line 30 is provided with a diffusor, so that the coolant 34 can be introduced uniformly into a nozzle 32, which surrounds the diffusor.

(21) In the case of the schematically illustrated nozzle 32, because of the geometry of the nozzle 32, in particular because of an appropriate constriction, the coolant 34 is formed into a uniform, accelerated flow, in which form it then leaves the nozzle 32.

(22) Following the nozzle 32 is a cooling chamber 4, which extends essentially parallel to the plane 10 defined by the rolled stock 2, also called the strip passline, the chamber being configured to apply the coolant 34 to the rolled stock 2. After the rolled stock 2 has been threaded into it, the cooling chamber 4 thus extends also essentially parallel to the rolled stock 2. In the cooling chamber 4, the coolant 34 flows out of the nozzle 32 and comes in contact with the rolled stock 2. Thus there is a transfer of heat from the rolled stock 2 to the coolant 34, at least in the area of the cooling chamber 4. As will be described further below on the basis of FIG. 5, the rolled stock 2 is cooled very effectively as a result of the long and defined contact time of the coolant 34 with the rolled stock 2especially as compared to the effectiveness of simply spraying the rolled stock 2.

(23) The cooling chamber 4 consists essentially of a chamber roof 40, which preferably follows immediately after the nozzle 32. The chamber roof 40 is arranged opposite the top surface 20 of the rolled stock 2, so that the coolant 34 flowing through the nozzle 32 is conducted from the nozzle 32 into the cooling chamber 4, in which the coolant 34 then flows along the rolled stock 2 in a manner essentially free of vortices.

(24) The thick arrow indicates the strip travel direction W of the rolled stock 2. It can be seen immediately that the cooling chamber 4, starting from the nozzle 32, is oriented in the direction opposite to the strip travel direction. In other words, the nozzle 32 is arranged downstream, with respect to the strip travel direction W, from the cooling chamber 4.

(25) The cross section of the cooling chamber 4 is essentially constant in the strip travel direction, so that the flow velocity of the coolant 34 in the cooling chamber 4 is essentially constant, and simultaneously an essentially vortex-free flow can also be formed. As a result, the coolant 34 comes in contact with the rolled stock 2 in the area of the cooling chamber 4 in such a way that an efficient and uniform flow without vortices is present here.

(26) At the end of the cooling chamber 4, the coolant 34 emerges as a diffuse flow and can be collected in the usual way.

(27) FIG. 4 shows the structure of the cooling device 3 schematically illustrated in FIG. 3 once again in detail, especially with respect to the flow relationships. The strip travel direction W of the rolled stock 2 is again indicated by the thick arrow.

(28) The velocity distribution of the flow within the cooling chamber 4 is shown schematically. The diagram at the bottom left shows the largely symmetric velocity profile of the flow without a moving strip, i.e., at zero strip velocity. With a moving strip or a non-zero strip velocity, an asymmetric velocity profile is obtained, as shown in the diagram at the bottom right. As a result of the movement of the strip, the relative velocity between the flow and the surface of the strip is increased, which amplifies the cooling effect, that is, the transfer of heat from the surface of the strip to the coolant.

(29) The nozzle 32 is configured in such a way that a uniform flow velocity across the entire cooling chamber 4 is obtained.

(30) FIG. 5 shows a comparison between the cooling device 3 as shown in FIGS. 2 and 3 and a conventional spray device 3. In the cooling device 3 according to FIGS. 2 and 3, an essentially uniform flow is formed, which is conducted through the cooling chamber 4. It is thus possible to achieve the heat transfer shown schematically under this device in the area of the cooling chamber 4. Thus a constant heat transfer is obtained on the surface 20 of the rolled stock 2, as can be seen from the schematic diagram underneath.

(31) In contrast, the spray device 3, as indicated by the arrows, results in a large amount of swirling and a considerable amount of coolant backspray. The resulting cooling action is thus evident only at individual points, as can be seen from the schematic diagram.

(32) FIG. 6 shows a schematic diagram of a preferred form of the cooling device 3, in which, at the transition from the nozzle 32 to the cooling chamber 4, a separation edge can be seen. This has the job of preventing the fluid flow from adhering to the roof of the cooling chamber and thus of conducting the flow to the surface of the strip and filling the cooling chamber more effectively. The separation edge in this example has been realized by an offset between the height of the nozzle gap and the roof of the chamber, so that the distance between the chamber roof and the strip surface is greater than the height H of the nozzle gap above the strip surface.

(33) FIG. 7 shows another preferred embodiment of the cooing device, in which the width of the cooling chamber 4 is adapted to the width of the strip material currently being processed. In the example shown, this is accomplished by shifting the two side walls of the cooling chamber 4, which are essentially parallel to the strip width. The side walls in FIG. 7 are shown in dash-dot line; they can be shifted in the direction of the double arrows. Adjusting the width of the channel ensures optimal guidance of the flow along the rolled stock and suppresses the formation of vortices. The distance between the edge of the strip and the side wall of the cooling chamber is in the range of 2-100 mm, and preferably in the range of 10-50 mm, wherein the channel width may be less than 10% greater than the strip width of the rolled stock.

(34) FIG. 8 shows another preferred embodiment of the cooling device, in which a flow brake in the form of, for example, a sealing strip a certain distance away from the strip surface or in the form of a similar cooling chamber constriction prevents the free outflow of the coolant from the cooling chamber.

(35) FIG. 9 shows another embodiment of a cooling device 3, wherein a cooling device 3 of the type already shown by way of example in FIGS. 2 and 3 is now arranged on both sides of the rolled stock 2. Thus the top surface and also the bottom surface of the rolled stock 2 can now be cooled.

(36) FIG. 10 shows another embodiment of a cooling device 3, wherein again the arrangement of nozzle 32 and cooling chamber 4 already familiar from the preceding exemplary embodiments is provided. Following the cooling chamber in the flow direction is now a drainage chamber 5, which is configured to collect the coolant 34 flowing through the cooling chamber 4 and to carry it away.

(37) The drainage chamber 5 is configured so that it is connected to the chamber roof 40 of the cooling chamber 4 and provides a collecting volume 50, in the side of which a drain opening 52, shown schematically, is arranged. The coolant 34 flows into the drain opening 52 and cannot contaminate the surroundings or the rolled stock 2. It is also easy in this way to recirculate the coolant 34, because, after it has been sent through the feed line 30 and the nozzle 32 and brought into contact with the rolled stock 2, it can then be removed from the rolled stock 2 via the drainage chamber 5.

(38) FIG. 11 shows a corresponding configuration, in which again a corresponding device with drainage device is shown on both the top and the bottom sides of the rolled stock 2.

(39) In FIG. 12, another device for cooling rolled stock 2 is provided, wherein again the device for cooling is provided with the nozzle 32, the cooling chamber 4, and the drainage chamber 5. By means of adjusting cylinders 6, the outer shroud 7 of the device can be manipulated in such a way that the flow direction of the coolant 34 can be changed. This is important when the direction in which the strip is traveling is reversed, as in the case of a reversing stand, for example.

(40) For this purpose, the outer shroud 7 is pushed from the first position, shown at the top at 12a, into a second position, shown at the bottom at 12b. Thus two feed lines 30 and two drains 52 are provided, which are connected to each other as necessary, depending on the position of the outer shroud 7, to achieve the desired flow of the coolant 34.

(41) FIG. 13 shows in general how the entire device can be swung away from the top and from the bottom of the rolled stock 2, i.e., from the passline 100, so that the stock can be threaded in more easily or so that maintenance work can be carried out more conveniently.

(42) FIG. 14 corresponds in principle to the exemplary embodiment shown in FIGS. 7 and 8. Upstream and downstream, in the strip travel direction W, from the cooling chamber, there is in each case an air-blast device, also called a removal device, as indicated schematically in the form of the blast nozzles 75. Upstream and downstream, in the strip travel direction W, from the cooling chamber 4 with nozzle 32 and drain chamber 5, there is in each case a removal device with barrier function and deflector plate 73, also shown schematically. The removal device protects adjacent systems from contamination. The blasts or backsprays discharged by the removal device, furthermore, can also provide a barrier function, and the off-flow of the escaping fluid can be optimized by the deflector plates. The blasts or backsprays keep the coolant 34 in the cooling chamber 4 or drive escaping coolant 34 back into the cooling chamber 4. The deflector plate collects escaping coolant and conducts it effectively away.

(43) In this way, other areas of the plant can be protected from contamination with coolant 34.

(44) FIG. 15 shows a schematic diagram of the automatic control mechanism for the present device for cooling rolled stock. In particular, the rolled stock 2 is guided through a rolling stand 1 and then treated with coolant 34 in a cooling device 3. The device for cooling the rolled stock 2 is supplied with the coolant by a pump circuit 8. The pump circuit 8 comprises a suction line 80, an automatically controlled pump 82, a coolant drain line 84, and a collecting tank/reservoir 86.

(45) The coolant is thus pumped from the collecting tank/reservoir 86 through the suction line 80 by means of the automatically controlled pump 82 into the device 3 for cooling rolled stock 2. There the coolant 34 is brought into contact with the rolled stock 2. Then the coolant is collected again by way of the drainage chamber 5 shown in the preceding figures and sent back to the reservoir/collecting tank 86 via the drain line 84.

(46) The automatically controlled pump 82 is actuated by an automatic control unit 100. The control unit 100 comprises a controller 110, which takes over the actual job of automatically adjusting the controllable pump 82 by adjusting its output, for example. The controller 110 is supplied with parameters 120, which comprise, for example, a characteristic curve of the controllable pump 82 or other parameters relating to the geometric configuration of the cooling chamber 4, to the different materials of the rolled stock 2, to different pass sequences, to different velocities of the rolled stock 2, etc.

(47) The various parameters of the rolling process measured by sensors are evaluated by an evaluation unit 130, on the basis of which the controller 110 is actuated.

(48) In the evaluation unit 130, sensors 140, 150, for example, which are configured as residual fluid or temperature sensors, participate in the evaluation of the actual state of the rolled stock 2. In addition, residual fluid sensors 140 can be used to monitor the correct functioning of the device for cooling rolled stock, so that residual fluid is not transported onward on the rolled stock 2 or is transported onward only within narrowly set limits. The temperature sensors can be used to adjust the cooling power of the device for cooling in such a way that the desired microstructure is obtained.

(49) A speed sensor 160 is also provided, which determines the speed at which the rolled stock 2 is coiled.

(50) The various parameters are evaluated in the evaluation unit 130 to obtain a uniform control command, which is then transmitted to the controller 110.

(51) Insofar as applicable, all of the individual features presented in the individual exemplary embodiments can be combined with each other and/or exchanged for each other without leaving the scope of the invention.

LIST OF REFERENCE SYMBOLS

(52) 1 rolled stock 10 strip passline 100 control unit 110 controller 120 parameter 130 evaluation unit 140 temperature sensor 150 residual fluid sensor 160 speed sensor 2 rolled stock 20 surface of the rolled stock 3 cooling device 3 nozzle 30 feed line (with diffusor) 32 nozzle 34 coolant 4 cooling chamber 40 cooling chamber roof 45 flow brake 5 drainage chamber 50 volume of the drainage chamber 52 drain opening 6 adjusting cylinder 7 outer shroud 73 deflector plate 75 blast nozzles 8 fluid circuit 80 suction line 82 automatically controlled pump 84 coolant drain line 86 reservoir W strip travel direction