Cooling device and method for operating same

Abstract

A cooling device for cooling a metallic item and a method for operating the cooling device. Such cooling devices having a plurality of cooling bars arranged in parallel in groups for applying a coolant to the metallic item are known in the prior art. In order to be able to set a desired distribution function of the coolant over the width of the metallic item as precisely as possible, the cooling device provides that similar application regions in at least two cooling bars within a group are each formed differently with respect to their contour and/or with respect to their surface area.

Claims

1. A cooling device for cooling a metallic item, comprising: at least one group of cooling bars having at least one first and one second cooling bar arranged in parallel for applying a coolant to the metallic item, wherein each cooling bar has at least one first and one second application region having application tubes or nozzles, which are arranged in succession along a longitudinal direction of the cooling bar; and a control unit having valves for individually adjusting a pressure and/or a volume flow of the coolant in each of the application regions; wherein the first application region of the first cooling bar comprises a contour and/or an area different from a contour and/or an area on the first application region of the second cooling bar adjacent to the first cooling bar in each group.

2. The cooling device as claimed in claim 1, wherein a boundary line between the first and second application regions of the first cooling bar and a boundary line between the first and second application regions of the second cooling bar are inclined at different angles α in relation to a longitudinal axis of the respective cooling bar; and/or wherein the boundary line between the first and second application region of the first cooling bar and the boundary line between the first and second application region of the second cooling bar are positioned differently along the longitudinal axis of the cooling bars.

3. The cooling device as claimed in claim 2, wherein the following applies to the angle α: 30≤α≤+30°.

4. The cooling device as claimed in claim 1, wherein each cooling bar also has, in addition to the first application region and the second application region, a third, right, application region, wherein the first application region is on a left side of the bar, and the second application region is between the first application region and third, right, application region; and wherein the first application region of the first cooling bar is designed differently in its contour and/or area than the first application region of the second cooling bar in the at least one group, and/or wherein the second application region of the first cooling bar is formed differently in its contour and/or area than the second application region of the second cooling bar in the at least one group, and/or wherein the third application region of the first cooling bar is formed differently in its contour and/or area than the right application region of the second cooling bar in the at least one group.

5. The cooling device as claimed in claim 4, wherein the first and third application regions are each triangular and the second application region is trapezoidal.

6. The cooling device as claimed in claim 4, wherein the first, second, and third application regions are each trapezoidal.

7. The cooling device as claimed in claim 4, wherein at least one of the cooling bars of each group has at least two parallel rows of application tubes or nozzles, wherein the boundary line extends between the application tubes or nozzles.

8. The cooling device as claimed claim 4, wherein the cooling bars of each group are each arranged immediately adjacent at least one other cooling bar and transversely to a transport direction of the cooling metal.

9. The cooling device as claimed in claim 8, wherein at least two cooling bars of each group have the same or a different number of application regions.

10. The cooling device as claimed in claim 9, wherein the same application regions in the first and the parallel second cooling bars of each group are connected to one and the same valve.

11. The cooling device of claim 1, wherein the first and second application regions in the first and the parallel second cooling bars of each group are connected to one and the same valve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Five figures are appended to the description, wherein

(2) FIG. 1 shows a cooling device according to the invention having a group of five cooling bars by way of example, wherein the application regions of the cooling bars are designed in the form of a first pattern or a first exemplary embodiment,

(3) FIG. 2 shows a second pattern or exemplary embodiment of the arrangement of the application regions within the group;

(4) FIG. 3 shows a third pattern or exemplary embodiment of the arrangement of the application regions within the group;

(5) FIG. 4 shows an example of the distribution of the volume flow of the coolant over the width of the metallic item according to the present invention; and

(6) FIG. 5 shows variants of the distribution according to FIG. 4 by variation of the volume flow of the coolant in the peripheral regions of the metallic item.

DETAILED DESCRIPTION

(7) The invention is described in detail hereinafter with reference to the mentioned figures in the form of exemplary embodiments. In all exemplary embodiments, the same technical elements are designated by the same reference numerals.

(8) FIG. 1 shows a cooling device 100 for cooling a metallic item 200, in particular a metal strip. The cooling device consists of a plurality of cooling bars 110-n arranged in parallel with n=1 . . . N, here N=5 by way of example, for applying a coolant 300 to the metallic item 200. The coolant is pumped from a tank into the cooling bars 110 with the aid of pumps 160 and valves 130. Each cooling bar 110-n is divided in its longitudinal direction into at least one left, one middle, and one right application region I, II, III having respective application tubes or nozzles 150. In this case, each two application regions are adjacent, which is why the description also refers to adjacent in pairs. Each application region I, II, III of a cooling bar is assigned a separate valve 130, so that a pressure or volume flow of the coolant can be applied individually to the individual regions. In FIG. 1, all left application regions I are connected, for example, to the same valve 130-I and are thus connected in parallel. Likewise, all middle application regions II of the cooling bars 110-n with N=1-5 are connected to the same valve 130-II and are thus also connected in parallel. Similarly, all right application areas III are connected to a third valve 130-III.

(9) In a more detailed variant, the respective similar application regions I, II, III are not each connected in parallel with respect to the coolant supply, but rather alternatively a separate valve can also be assigned to each application region of each cooling bar. In the exemplary embodiment shown in FIG. 1, where the group G has five cooling bars 110-1 . . . -5 having three application regions each, then, for example, 3*5=15 control valves would be provided for this group. In principle, all subsets are also conceivable, wherein then the individual similar application regions are each only partially connected in parallel.

(10) In this way, in particular, the pressures or the volume flows of the coolant in the individual application regions I, II, III can be set individually at least in groups, here for the one group G shown.

(11) All valves 130 and all pumps 160 are connected to a control unit 120 and are activated individually by this control unit.

(12) In the first exemplary embodiment shown in FIG. 1, the application regions I, II, III of the cooling bars 110-1 . . . -5 each differ in the size of their area, i.e., with respect to their surface area. Specifically, it can be seen that the border lines 140-n with n=1 . . . −5 are each positioned differently in the individual cooling bars in the longitudinal direction of the cooling bars. The slopes of all border lines 140 are all equal in the exemplary embodiment shown in FIG. 1, therefore the angles α1 and α2 are also equal everywhere, however, the starting points xn, xn′ with x=1 . . . 5, are each different, here as an example in all cooling bars 110-1 . . . -5 of the group G. Specifically, the area of the trapezoidal middle application region II thus becomes larger and larger from the cooling bar 110-1 to the cooling bar 110-5, while at the same time the areas of the left and right application regions I, III successively become smaller and smaller. This is because the total spray area of each individual cooling bar always remains equal even upon a displacement of the boundary lines 140.

(13) It can furthermore be seen that in the cooling bars 110-1 . . . -4, all application regions are always trapezoidal, while in the fifth cooling bar 110-5, the two outer application regions I and III are each triangular and only the middle cooling region II is trapezoidal.

(14) Each of the cooling bars has at least one, but typically a plurality of application tubes or nozzles 150 in each application region, wherein these application tubes or nozzles can also solely be formed in the form of simple openings in the cooling bar.

(15) The cooling bars 110-n extend with their longitudinal axis transversely to the transport direction T of the rolled item 200.

(16) In contrast to what is shown in FIG. 1, the individual cooling bars 110 of a group G can in principle also at least partially have a different number of application regions.

(17) A group G of cooling bars 110-n is defined via a desired distribution of the coolant 300 over the width of the metallic item 200. The desired distribution function results from superimposing the individual distribution functions of the individual cooling bars within the group G. The more cooling bars having differently formed application regions I, II, III are combined in a group, the more precisely a desired overall distribution function for the coolant can be implemented. In particular, a technically preferred fine parabolic application of coolant 300 to the metallic item 200 may then be implemented.

(18) FIG. 2 shows a second exemplary embodiment of the design of the application regions, which each differ in their surface area and in their contour from cooling bar to cooling bar. In the second exemplary embodiment, the two outer, i.e., the left and the right application region I, III are each triangular and the middle region is trapezoidal. The different design in area and contour is implemented in the second exemplary embodiment in that the boundary lines 140 are each inclined differently in relation to the longitudinal direction of the cooling bars from cooling bar to cooling bar The angles of inclination α1 . . . −α5 become larger and larger from the first cooling bar 110-1 to the last cooling bar 110-5 of the group G. The trapezoidal middle application regions are thus always enlarged, while the respective outer application regions I and III are proportionally reduced in size. In the second exemplary embodiment shown in FIG. 2, the boundary lines 140 each begin in the lower left corner and in the lower right corner. This means that the different application regions in the second exemplary embodiment are only due to a change of the angle α of the boundary lines in relation to the longitudinal axis of the cooling bars, but without the boundary lines 140 being positioned differently along the x-axis.

(19) FIG. 3 shows a third exemplary embodiment of the configuration of the application regions I, II, and III in a group G of five cooling bars. In the third example, the difference of the individual application regions from cooling bar to cooling bar is implemented in that both the angles of inclination α1 . . . −α5 in relation to the longitudinal axis of the cooling bars and also the positions x1 . . . −x5 of the boundary lines along the x-axis or the longitudinal axis of the cooling bars can be varied from cooling bar 110-1 to cooling bar 110-5.

(20) FIG. 4 shows by way of example a distribution function of the average volume flow of the coolant 300 over the width of the metallic item 200. The distribution function shown is an example of how, using the combination of a plurality of cooling bars 110-1 . . . -5 each having different application regions I, II, III within a group G, as shown in FIGS. 1 to 3, in particular a steady parabolic distribution can be implemented over the width of the metallic item. The emphasis here is on the word “steady”. This means that the transitions between individual linear sections of the distribution function do not have jumps, but instead run relatively smoothly. The transitions can be made smoother the more cooling bars are in the group and the more the application regions within a group overlap. Notwithstanding the symmetrical distribution shown in FIG. 4, an asymmetrical setting of the left and right sides is also possible.

(21) FIG. 5 initially shows the same distribution function as in FIG. 4, see the middle function in FIG. 5. Furthermore, FIG. 5 shows a function that is more strongly or weakly curved in the peripheral regions than the middle function; this is implemented by a reduction of the quantities of water in the peripheral zones. Finally, a differently modified distribution function can be seen above the function from FIG. 4; this is implemented by a corresponding increase of the quantities of water in the peripheral zones. It is particularly advantageous if not all similar peripheral zones within a group are connected in parallel with respect to the coolant application here, i.e., the same volume flow or the same pressure for the coolant is applied to them, but rather if these adjustment parameters are adjustable by control valves provided individually for the individual application regions per cooling bar.

(22) Overall, FIG. 5 shows the possibilities when using different application regions in the cooling bars of a group with simultaneous variation of the quantities of coolant or the pressure of the coolant in the individual application regions of a group.

(23) The cooling device 100 according to the invention is typically connected downstream of the last rolling stand of a rolling mill. At least one first group G of cooling bars 110 is arranged in the cooling device to apply the coolant to the upper side of the metallic item and/or at least one second group is arranged to apply the coolant to the lower side of the metallic item.

(24) The pressure or the volume flow of the coolant 300 in the individual applications I, II, and III of at least one cooling bar 110 within the group G can be adjusted in each case as a function of at least one of the following parameters: The width of the metallic item, the temperature distribution of the metallic item to be cooled over its width, or as a function of the chemical composition of the material or the material properties of the metallic item.

(25) These mentioned parameters can be measured and/or calculated either at the input and/or at the output of the cooling device. If they are detected at the input of the cooling device, this is thus referred to as a public control; if the parameters are detected at the output of the cooling device, it can thus be a regulation.

(26) While the design of the individual application regions I, II, and III shown by way of example in FIGS. 1 to 3 is permanently predetermined in each case in each cooling device according to the invention, the distribution of the pressure or the volume flow of the coolant 300 over the length of the cooling bar 100 or in the individual application regions I, II, and III can be changed as a function of the above-mentioned parameters during the passage of the metallic item 200 through the cooling device 100.

LIST OF REFERENCE SIGNS

(27) 100 cooling device 110-n cooling bars 110-1 first cooling bar 110-2 second cooling bar 120 control unit 130 valves 140 boundary line between two adjacent cooling bars of a cooling bar 150 application tubes or nozzles 200 metallic item, in particular rolled item 300 coolant G group T transport direction of the rolled item X longitudinal direction I left application region II middle application region III right application region α angle