Cooling section comprising power cooling and laminar cooling

Abstract

A cooling section for flat rolling stock (1) has a working region (2), through which the flat rolling stock (1) is guided. The working region (2) can be supplied with a liquid coolant (4) by means of a number of spray beams (3i). The liquid coolant (4) is fed from a reservoir (7) for the liquid coolant (4) to the spray beams (3i) by means of a pump (5) and a supply system (6). Valves (9i) are arranged upstream of the spray beams (3i) in the supply system (6). Opening positions (si) of the valves (9i) are set by a control unit (10) of the cooling section according to a respective sub-flow (fi) that is to be applied to the flat rolling stock (1) by means of each spray beam (3i). Also, the delivery rate (M) of the pump (5) and/or a line pressure (p) generated by the pump (5) in the supply system (6) are set by the control unit (10) according to the total flow (F) that is to be applied to the flat rolling stock (1) by means of all the spray beams (3i).

Claims

1. A cooling section for a rolling stock, comprising: the cooling section having a working region through which flat rolling stock is guided, a plurality of spray beams in the working region configured for supplying the working region with a liquid coolant by means of the plurality of the spray beams wherein the liquid coolant is fed to the spray beams (3i) from a reservoir for the liquid coolant; a supply line system from the reservoir to the beams, including a pump positioned downstream of the reservoir for pumping coolant from the reservoir to the spray beams via valves leading to the spray beams; the valves are arranged downstream of the pump and upstream of the spray beams (3i) within the supply line system, the valves are settable to selected valve opening positions, a control device configured for setting each of the valves according to a respective partial flow (fi) to be applied to the rolling stock (1) by the respective spray beams supplied with the coolant through the valves; and also wherein a delivery power (M) of the pump and/or a line pressure (p) generated in the supply line system by the pump is settable by the control device according to a total flow (F), which includes all of the respective partial flow (fi) set for each of the valves, to be applied to the rolling stock by all of the spray beams together.

2. The cooling section as claimed in claim 1, wherein the line pressure (p) in the supply line is settable between a minimum value (pmin) and a maximum value (pmax), wherein the opening settings (si) of the valves are settable in step-free fashion or in various steps between a respective fully closed setting (si0) and a respective fully open setting (si 1), and if the line pressure (p) is at the maximum value (pmax), at least one respective opening setting (si) of the valves, at which the liquid coolant flowing through the respective valve cavitates.

3. The cooling section as claimed in claim 2, further comprising the valves being configured such that if the line pressure (p) is at the maximum value (pmax), the valves have a respective fully open setting at which there is a respective maximum flow (fi1) therethrough and, at the open setting (si) of each valve at which the liquid coolant flowing through the respective valve cavitates, there is a respective cavitation flow (fiK).

4. The cooling section as claimed in claim 1, wherein the valves (9i) are comprised of butterfly valves.

5. The cooling section of claim 3, wherein a ratio of the respective maximum flow (fi1) to the respective cavitation flow (fiK) is at most 5:1.

6. The cooling section as claimed in claim 1, wherein the rolling stock is a flat rolling stock having flat surfaces on which the spray beams spray coolant.

7. The cooling section as claimed in claim 2, wherein the rolling stock is a flat rolling stock having flat surfaces on which the spray beams spray coolant.

8. The cooling section as claimed in claim 3, wherein the rolling stock is a flat rolling stock having flat surfaces on which the spray beams spray coolant.

9. The cooling section as claimed in claim 5, wherein the rolling stock is a flat rolling stock having flat surfaces on which the spray beams spray coolant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a side view of a cooling section,

(2) FIG. 2 shows characteristic curves and

(3) FIG. 3 shows a valve in section.

DESCRIPTION OF AN EMBODIMENT

(4) As shown in FIG. 1, a cooling section for a flat rolling stock 1 has a working region 2 through which the flat rolling stock 1 is guided. A number of spray beams 3i (i=1, 2, 3, . . . ) are arranged in the working region 2. The working region 2 can be supplied, by means of the spray beams 3i, with a liquid coolant 4. The liquid coolant 4 is fed to the spray beams 3i from a reservoir 7 for the liquid coolant 4 via a pump 5 and a supply line system 6. The spray beams 3i are generally, as shown in the representation of FIG. 1, arranged both above and below a pass line 8, such that the spray beams 3i can apply the liquid coolant 4 to the flat rolling stock 1 both from above and from below the opposite surfaces of the flat stock. In some cases, however, it can be sufficient for the spray beams 3i to be arranged only above the pass line 8.

(5) Within the supply line system 6, valves 9i are arranged upstream of the spray beams 3i. The valves 9i or, more specifically, their opening settings si, can be set by a control device 10. The valves 9i are controlled by the control device 10 such that the opening settings si of the valves 9i are set in accordance with a respective partial flow fi, which is to be applied to the flat rolling stock 1 by means of the respective spray beam 3i. Furthermore, the control device sets a delivery power M of the pump 5 in accordance with a total flow F which is to be applied to the flat rolling stock 1 by means of all of the spray beams 3i together. As an alternative to the delivery power M, the pump 5 can be controlled in a manner corresponding to the total flow F so as to set a line pressure p which is generated in the supply line system 6 by means of the pump 5. The total flow F can be determined by the control device 10, automatically and directly by summing the partial flows fi.

(6) The control device 10 generally takes the form of a software-programmable control device. This is indicated in FIG. 1 by the fact that the abbreviation pP, for microprocessor, is shown in the control device 10. In this case, the control device 10 is programmed with a computer program 11. The computer program 11 comprises machine code 12 which can be directly executed by the control device 10. In this case, the execution of the machine code 12 by the control device 10 effects the corresponding formation and mode of operation of the control device 10.

(7) The control device 10 accordingly controls the pump 5 such that the line pressure p in the supply line system 6 can be set between a minimum value pmin and a maximum value pmax.

(8) Furthermore, the control device 10 accordingly controls the valves 9i such that their opening settings si can be set between a respective fully closed position si0 and a respective fully open position si1. It is possible, as shown in FIG. 2, for the opening positions si to be set in a step-free manner.

(9) Alternatively, setting could be effected in multiple steps. A respective partial flow fi corresponds to every opening position si of the valves 9i. In addition, the partial flow fi is also, as shown in FIG. 2, dependent on the line pressure p.

(10) In the event that the line pressure p is at the maximum value pmax, there exists, as shown in FIG. 2, at least one respective opening position si of the valves 9i at which the liquid coolant 4 flowing through the respective valve 9i cavitates, i.e. bubbles form in the liquid coolant 4 flowing through the respective valve 9i, downstream of the respective valve 9i as seen in the direction of flow.

(11) This effect, which is per se disadvantageous and undesired, can be readily accepted within the context of the present invention because, within the context of the present invention, in order to obtain a certain partial flow fi, it is possible to vary not only the opening position si of the corresponding valve 9i, but also the delivery quantity M of the pump 5 and/or the line pressure which the pump 5 generates in the supply line system 6.

(12) The following statements relate to the case in which the line pressure p is at the maximum pressure pmax. As shown in FIG. 2, the liquid coolant 4 flowing through the respective valve 9i has, at the respective fully open position si1, a respective maximum flow fi1. At that respective opening position si at which the liquid coolant 4 flowing through the respective valve 9i cavitates, the liquid coolant has a lower partial flow fiK, hereinafter termed cavitation flow fiK. The ratio of the respective maximum flow fi1 to the respective cavitation flow fiK is generally at most 5:1. It can also be lower, for example 3:1 or 2:1.

(13) By virtue of the fact that it is possible to avoid cavitation by accordingly reducing the delivery power M and/or accordingly reducing the line pressure p, it is clearly possible for the valves 9i to be formed as butterfly valves, as shown in FIG. 3.

(14) The present invention has many advantages. In particular, cavitation can easily be avoided during operation as laminar cooling. Furthermore, it is clearly possible to retro-fit existing power cooling installations. All that is necessary is for the control device 10 to be exchanged or reprogrammed and for the pump 5 to be appropriately capable.

(15) Although the invention was described and illustrated in more detail using the preferred exemplary embodiment, the invention is not restricted by the disclosed examples and other variations can be derived herefrom by a person skilled in the art without departing from the scope of protection of the invention.

LIST OF REFERENCE SIGNS

(16) 1 Flat rolling stock 2 Working region 3i Spray beam 4 Coolant 5 Pump 6 Supply line system 7 Reservoir 8 Pass line 9i Valves 10 Control device 11 Computer program 12 Machine code F Total flow fi Partial flows fiK Cavitation flow fi1 Maximum flow M Delivery power p Line pressure pmin Minimum value pmax Maximum value si Opening positions si0 Fully closed positions si1 Fully open positions