EP3723919A1

EP3723919A1 - Improved control of the water economy of a cooling path

Info

Publication number: EP3723919A1
Application number: EP18800210.9A
Authority: EP
Inventors: Klaus Weinzierl; Manfred Eder; Jurij Razinkov; Christian Schlapak
Original assignee: Primetals Technologies Austria GmbH; Primetals Technologies Germany GmbH
Current assignee: Primetals Technologies Austria GmbH; Primetals Technologies Germany GmbH
Priority date: 2017-12-11
Filing date: 2018-11-16
Publication date: 2020-10-21
Also published as: US20200376527A1; WO2019115145A1; CN111432950A; CN111432950B; EP3495056B1; EP3495056A1; US11135631B2

Abstract

In a cooling path, hot rolled material (3) composed of metal is cooled. The cooling path has a pump (7) which extracts coolant (2) from a coolant reservoir (8) and feeds said coolant via a line system (9) to a number of coolant outlets (4, 6) which are controlled by means of valves (10) positioned upstream of the coolant outlets (4, 6). A control device (11) of the cooling path determines activation states (Ci) for the valves (10) for a respective point in time taking into consideration coolant flows (Wi) which are intended to be discharged via the coolant outlets (4, 6) at the respective point in time, in conjunction with a working pressure (pA) of the coolant (2) prevailing at the inlet side of the valve (10). By adding the coolant flows (Wi), said control device determines a total coolant flow (WG). Taking into consideration the total coolant flow (WG), the working pressure (pA) of the coolant (2) and additionally a change (5WG) of the total coolant flow (WG), said control device determines a pump pressure (pP) that is intended to prevail at the outlet side of the pump (7) such that the working pressure (pA) is attained at the inlet side of the valves (10). Taking into consideration the total coolant flow (WG), the pump pressure (pP) and a suction pressure (pS) prevailing at the inlet side of the pump (7), said control device determines an activation state (CP) for the pump (7). Said control device activates the valves (10) and the pump (7) in accordance with the determined activation states (Ci, CP). The control device (11) performs said steps cyclically.

Description

description

Name of the invention

Improved control of the water management of a cooling line

Field of engineering

The present invention relates to a Betriebsverfah reindeer for a cooling section for cooling of hot metal stock, wherein the cooling section comprises a pump which removes coolant from a coolant reservoir and feeds a line system to a number of coolant outlets gesteu the upstream of the Kühlmittelauslässen valves be

- Wherein a control device of the cooling section cyclically for a respective time

- Taking into account coolant flows, which are to be abgege ben at the respective time via the coolant outlets, determined in conjunction with a eingangssei term of the valves pending working pressure of the coolant control states for the valves,

- determined by summing the coolant flows a total cooling medium flow,

- Taking into account the total coolant flow and the working pressure of the coolant, a pump pressure he mediates, the output side of the pump should prevail, so that the input side of the valves of the working pressure he will reach,

- Taking into account the total coolant flow, the pump pressure and an inlet side of the pump herrenden suction pressure determines a drive state for the pump and

- controls the valves and the pump according to the determined control states.

The present invention is further based on a computer program comprising machine code which is controlled by a control unit. Device for a cooling line can be processed, wherein the processing of the machine code by the control device causes the control device operates the cooling section according to egg nem such operating method.

The present invention is further based on a control device for a cooling section, wherein the control device is programmed with such a computer program, so that the control device operates the cooling section according to such an operating method.

The present invention is further based on a cooling line for cooling hot metal stock,

- wherein the cooling section comprises a pump which removes coolant from a coolant reservoir and supplies via a Lei management system to a number of coolant outlets, which are controlled via the Kühlmittelauslässen upstream valves ge,

- Wherein the cooling section has such a control device, which drives the cooling section according to such Betriebsver.

State of the art

The abovementioned objects are known, for example, from WO 2013/143 925 A1. WO 2014/124 867 A1 discloses a similar disclosure content.

In cooling sections, rolled metal, in particular steel, is cooled after rolling. Examples of such cooling sections are the downstream of a hot strip mill cooling section with or without intensive cooling and the so-called Quette a plate mill. In particular, in a downstream of the rolling mill cooling section is an exact temperature control üb Lich. But even in the case of an arrangement within or in front of a rolling train - for example, between a roughing mill and a finishing train - is the defined and exact on bringing a desired amount of coolant of great importance. tion. Particularly in the case of cooling between a roughing train and a finishing train, particularly high demands are placed on the dynamics of the management of the coolant owing to the high quantity requirement for coolant.

The coolant is usually water or at least substantially consists of water.

The amounts of water to be applied are considerable. In some cases, up to 20,000 m ³ / h must be applied to the hot rolling stock over a distance of only a few meters (for example 10 m to 20 m). For precise control of the cooling, it is not only necessary to timely and correctly control the valves of the cooling section. It is also necessary to provide the appropriate amounts of water on the input side of the valves available and also to take back. The required control times are often in the range close to 1 second, in some cases even less than 1 second.

In some cases, it is possible to ensure the required dynamics of the water balance due to a corresponding mechanical design of the cooling section. For example, in the immediate vicinity of the coolant outlets as a coolant reservoir set up a water tank and supply the coolant outlets directly or booster pumps with water from the water tank. In this case, the line system between the coolant reservoir and the cooling medium outlets can be made sufficiently short. As a result, the required acceleration of the amount of water is possible without the accuracy of the cooling suffers to any significant extent.

In other cases, however, it is not possible to place a water tank in sufficient proximity to the coolant outlets. Sometimes, there is only space outside the production hall for installing such a water tank. The pipe system for supplying the coolant outlets has in this case a considerably greater length, for example, about 100 m. It is even possible that no water tank can be installed at all. In this case, the line system, which promotes the coolant to the Kühlmittelaus let, have a length of several 100 m. If it is not possible to place a water tank in sufficient proximity to the coolant outlets, larger quantities of water - often several 100 t - must first be accelerated if the requested coolant quantity is changed. In the prior art, this acceleration leads to a delay in providing the required quantities of coolant.

To solve this problem ver different solutions are known in the prior art.

Thus, for example, from WO 2014/032 838 Al known, in addition to Nutz-Kühlmittelauslässen, via which the cooling medium is applied to the hot rolling stock, to provide bypass cooling medium outlets. In this case, the coolant can be removed via the bypass coolant outlets without applying it to the hot rolling stock. When the hot rolling stock enters a cooling zone in which the coolant is to be applied to the hot rolling stock, the bypass coolant outlets upstream valves are closed or closed, while the Nutz-Kühlmittelausläs sen upstream valves are opened. In this way, the coolant which is moved through the conduit system, only to a lesser extent or even accelerated nigt. A disadvantage of this approach, however, is that even then large amounts of coolant to be pumped through the line system, if no hot rolling is to be cooled. Accordingly high are the energy consumption for the pump and the consumption of coolant.

Another known solution is to provide a riser with an overflow in the vicinity of the cooling area. A riser requires less space than a water tank. But it can save only a small amount of coolant. In this case, therefore, the maximum amount of coolant he is waiting for continuously promoted to the cooling area. Already this is a disadvantage, since always the maximum amount of coolant required must be provided, while in a solution with a water tank only the average amount of water required should be provided. The height of the riser creates a nearly constant backpressure that is independent of the actual need for coolant. Again, the consumption of coolant and energy is correspondingly high, as always an unnecessarily large amount of coolant is provided. Furthermore, the pressure can not be adjusted. It always corresponds to the pressure resulting from the height of the column of coolant in the riser to the overflow.

The procedures known from WO 2013/143 925 A1 already represent a considerable advance over these solutions. However, these solutions are also still able to be improved.

Summary of the invention

The object of the present invention is to provide possi possibilities, by means of which even without greater or lesser storage capacity for coolant between the Pum PE and the Kühlmittelauslässen in an efficient manner at any time with high accuracy, the required amount of coolant can be made available.

The object is achieved by an operating method with the Merkma len of claim 1. Advantageous embodiments are the subject of the dependent claims 2 to 12.

According to the invention, an operating method of the type mentioned at the outset is configured in such a way that the control device of the cooling section not only takes into account the total coolant flow and the working pressure of the coolant cyclically for the respective point in determining the pump pressure, which should prevail on the pump side, but additionally a change in the total coolant flow was also taken into account. As a result, be taken into account as a result for the pump pressure to what extent the befind Liche amount of coolant in the line system must be accelerated or delayed. As a result, the respectively desired total coolant flow is achieved in a considerably more dynamic manner than in the prior art.

In a preferred embodiment, the control device takes into account, when determining the pump pressure, a line resistance of the line system to be overcome by the total coolant flow. This results in an even higher accuracy in the determination of the pump pressure and thus the determination of the drive state of the pump.

In a particularly preferred embodiment of the present invention, the control means are in addition to the cooling medium flows to be dispensed at the respective time via the cooling medium outlets for a Prognosis rizont predicted coolant flows known that delivered for a number of future times on the Kühlmittelausläs se should be. In this case, it is possible that the control device takes into account the predicted coolant flows at least one of the future points in time when determining the drive state of the pump.

In particular, it is possible for the control device to determine the associated total coolant flow for at least one future time and to take it into account when determining the change in the total coolant flow. In a simplest case, for example, the deviation from the total coolant flow for the respective time can be determined.

For even better results, the control device continues to determine the change in the total coolant flow in addition to the predicted coolant flows of the at least one future point in time also takes into account the total coolant flow of at least one past time. In this case, the respective time is preferably in the middle between the at least one future time and the at least one past time.

In a particularly preferred embodiment, the coolant outlets comprise useful coolant outlets and bypass coolant outlets. In this case, the hot rolling stock is finally cooled by means of the useful coolant outlets from given coolant flows. The bypass Kühlmittelaus outlets serve as a way to influence the total flow of coolant without changing the applied to the hot rolling stock coolant flows. In the case of this embodiment, the control means is based on the coolant streams to be delivered for the respective time and / or the future times via the useful coolant outlets, the cooling medium flows to be delivered via the bypass coolant outlets for the respective time and / or the future time in that any total flow of refrigerant taken into account at a prior time prior to the time in determining the change in the total flow of refrigerant valid for the earlier time is maintained.

It can thereby be achieved that the time course of the drive state of the pump has a relatively low dynamics. Thus, a sufficiently "smooth" control of the pump can be achieved.This increases the service life of the pump and simplifies its activation.Of course, a configuration without bypass coolant outlets can be realized, in which therefore only Nutz-Kühlmittelaus outlets are available. In this case, on the one hand, however, the pump must be controlled with a relatively high degree of dynamics, and in addition, in cases in which a change can not be effected sufficiently quickly even when the pump is controlled with a high degree of dynamics, a temporary deviation from the actual value must occur pumped by the pump. total coolant flow of a desired total coolant flow can be accepted.

Alternatively or in addition to the consideration of prognos ticated coolant flows of the at least one future time in determining the change in the total cooling medium flow, it is possible that the control device on the hand of the forecast - if necessary - makes a forward de adjustment of the drive state of the pump. In particular special it is possible that the control device in the determination of the drive state of the pump - ie the determination of the drive state, with which the pump is to be activated at the respective time,

- For the future time points on the basis of the respective prog nostizierten coolant flows determined a respective prognosti ed total coolant flow,

- For the future time changes of the determined total coolant flows determined and

- For the respective time and / or future time points within the forecast horizon, the respective total cooling medium flows depending on maintaining or exceeding a predetermined maximum change retains or ve outlook adapts, so that, if possible, both the change of the total coolant flow for the respective time and the changes the calculated total coolant flows comply with the maximum change for the future times.

This procedure corresponds to the usual procedure in the context of a model predictive control.

If a knowledge or forecast of future total cooling medium flows is not possible, it is still possible to equalize the control of the pump. In this case to summarize the coolant outlets - as before - Nutz coolant outlets and bypass coolant outlets. The functionality of the corresponding coolant outlets is also as before. In this case, the controller determines the over the coolant flows to be delivered by the bypass coolant outlets such that coolant flows to be delivered via the bypass coolant outlets are as close as possible to a bypass desired coolant flow and a change in the total coolant flow to be delivered via the useful coolant outlets and the bypass coolant outlets is minimized ,

The valves may be in individual cases switching valves that can only assume two switching states, namely fully ge opens and fully closed. Preferably, however, the valves are infinitely or at least in several stages controllable. Thus, there is preferably at least one intermediate position of the respective valve between "fully open" and "completely closed".

The control device preferably determines the working pressure in such a way that the activation states of the valves keep minimum distances to a minimum activation and a maximum activation and the activation state of the pump is kept constant as far as possible. As a result, the pump must be controlled with less dynamics.

In the context of determining the pump pressure, the control device preferably also takes into account a height difference to be overcome. The height difference represents a con stant offset for the pump pressure.

Preferably, the control device additionally determines a control signal for a pump connected in parallel short-circuit valve and controls the short-circuit valve according to the determined control signal. As a result, operating conditions of the pump can be achieved which would be impossible or inadmissible without a short-circuit valve. The rückge over the short-circuit valve led coolant flow can be supplied as needed the Kühlmittelreser voir or a connecting line between the Kühlmittelre reservoir and the pump. The object is further achieved by a computer program having the features of claim 13. According to the invention causes the execution of the computer program by the Steuerein direction that the control device operates the cooling section according to an operating method according to the invention.

The object is further achieved by a control device for a cooling section with the features of claim 14. According to the invention, the control device is programmed with a computer program according to the invention, so that the control device operates the cooling section according to an operating method according to the invention.

The object is further achieved by a cooling section for cooling of hot metal rolling with the features of claim 15. According to the invention, the cooling section has a control device according to the invention which operates the cooling section according to an operating method according to the invention. A cooling region of the cooling section, within which the coolant is applied to the hot rolling stock, can be arranged in particular within a rolling train and / or upstream of a rolling train and / or downstream of the rolling train. The term "and / or" is to be understood in the sense that the cooling area can be arranged completely within the rolling train, completely downstream of the rolling train or partially disposed within the rolling train and partially downstream of the rolling mill for an arrangement in front of the rolling train.

Brief description of the drawings

The above-described characteristics, features and advantages of this invention and the manner in which they are achieved will become clearer and more clearly understood in connection with the following description of the Ausführungsbei games, which are explained in more detail in conjunction with the drawings. Here are shown in a schematic representation: 1 shows a cooling section,

2 shows a flow chart,

3 shows a valve characteristic,

4 shows a pump curve,

5 shows a time diagram,

6 shows a flow chart,

7 shows a time diagram,

8 shows a flow chart,

9 a pump diagram,

10 shows a pump with a parallel short

closing valve and

11 shows a cooling section.

Description of the embodiments

According to FIG. 1, a cooling section has a cooling region 1. Within the cooling region 1, a liquid coolant 2 - usually water - are applied to a hot rolling stock 3 and thereby the hot rolling 3 are cooled. The hot rolling stock 3 is made of metal, for example steel. For applying the liquid coolant 2 to the hot rolling stock 3, a number of useful coolant outlets 4 are arranged in the cooling area 1. The cooling area 1 is accordingly arranged as shown in FIG 1 partially within a rolling train. This is indicated in FIG 1, characterized in that one of the Nutz-Kühlmittelauslässe 4 a last rolling stand 5 of the rolling train (for example, a finishing train) is arranged upstream. However, the cooling area 1 could also be arranged fully constantly within the rolling train. The Kühlbe rich 1 is still partially downstream of the rolling mill. This is indicated in FIG 1, characterized in that the other useful coolant outlets 4 are arranged downstream of the last roll stand 5 of the rolling mill. However, the cooling area 1 could just as easily be arranged downstream of the rolling train. In the case of partial or complete Nachordnung the Kühlbe can range 1, for example, between the last rolling stand 5 and a reel 5 'be arranged. Furthermore, it is also possible, please include, that the cooling area 1 completely or partially the Walzstraße is arranged upstream. This is not shown in FIG 1 and the other figures.

In addition to the Nutz-Kühlmittelauslässen 4 vorzugswei se continue bypass coolant outlets 6 are available. In Figure 1, only a single such bypass coolant outlet 6 is shown. As a rule, only a single bypass coolant outlet 6 is present. In principle, however, a plurality of bypass coolant outlets 6 may also be present. Independently of the number of bypass coolant outlets 6, however, the cooling of the hot rolling stock 3 takes place exclusively via the useful coolant outlets 4. Coolant 2, which is discharged via one of the bypass coolant outlets 6, does not serve to cool the hot rolling stock 3. For example, this part of the coolant 2 can be collected and returned via a collecting container 6 '. The return of the Kühlmit means 2 from the collecting container 6 'is not provided in FIG 1 with dar.

The cooling section has a pump 7. The pump 7 can remove coolant 2 from a coolant reservoir 8, for example a water tank, and supply the coolant outlets 4, 6 via a line system 9. In the context of the present invention, the term "pump" is used in a generic sense, meaning that the pump 7 can be a single pump or a plurality of pumps arranged one behind the other and / or in parallel.

Between the pump 7 and the coolant outlets 4, 6 are

Valves 10 are arranged. By means of the valves 10 can Kühlmit telströme Wi, which are discharged through the coolant outlets 4, 6, are controlled. The index i stands, if it has the value 0, for the bypass coolant outlet 6, the associated coolant flow WO thus for the coolant flow discharged via the bypass coolant outlet 6. In an analogous manner, the index i, if it has the value 1, 2,... N, for each one of the Nutz coolant outlets 4, the associated coolant flow Wi thus for the over the respective Nutz- Coolant outlet 4 discharged coolant flow. The Kühlmit telströme Wi have the unit m ³ / s.

The cooling section has a control device 11, which operates the cooling section according to an operating method which will be explained in more detail below.

The control device 11 is usually designed as software programmable control device. This is indicated in FIG 1 by the fact that the microprocessor character "mR" is drawn into the control device 11. The control device 11 is programmed with a computer program 12. The computer program 12 comprises machine code 13 which can be processed by the control device 11 The programming of the control device 11 with the computer program 12 (or, equivalently, the processing of the machine code 13 by the control device 11) causes the control device 11 to operate the cooling path according to the operation procedure described below.

Due to the programming with the computer program 12, the control device 11 carries out the operating method explained below in conjunction with FIG. 2:

In a step S1, the controller 11 for a respective time for the Nutz coolant outlets 4, the respective coolant flow Wi known. The respective Kühlmit telstrom Wi is that coolant flow to be delivered to the time jewei time on the respective Nutz-Kühlmittelauslass 4.

In a step S2, the control device 11 determines the coolant flow W0. The coolant flow WO is that coolant flow which is to be discharged at the respective time via the bypass coolant outlet 6. In general, the determination of the coolant flow WO as a function of speed depends on the sum of the useful coolant outlets 4. to be admitted coolant flows Wi. This will become apparent from later executions.

In a step S3, the control device 11 forms by summing the coolant flows Wi a valid for the respective time total coolant flow WG.

In individual cases, there may be occurrences that in addition to the Nutz coolant outlets 4 and the bypass coolant outlet 6 even more consumers are ruled out to the line system 9. In this case, the amount of coolant required by the other consumers must also be taken into account when determining the total coolant flow WG. Often the other consumer is controlled by the control device 11, so that this is readily possible. Age natively, it is possible, for example, an actual size erfas sen, on the basis of which the current consumption of further consumer Ver can be determined. If no further information is available, the amount of coolant required by the other consumers can also be estimated.

In a step S4, the control device 11 determines a change 5WG of the total coolant flow WG. The change 5W of the total refrigerant flow WG indicates the extent to which the total refrigerant flow WG changes at that time. It is therefore the derivation of the total coolant flow WG over time. The control device 11 can use to determine the change 5W of the total coolant flow WG in particular a total coolant flow WG ', which is known to her from a previous cycle.

In a step S5, the controller 11 updates the total refrigerant flow WG 'for the previous cycle. For example, it assumes the value for the total coolant flow WG, which it has determined in step S3.

In a step S6, the controller 11 sets an operating pressure pA (unit: N / m ² ). The working pressure pA is the pressure that the coolant 3 on the input side of the valves Ven 10 should have. It is possible that the working pressure pA of the control device 11 is predetermined. Alternatively, it is possible that the control device 11 independently determines the working pressure pA.

In a step S7, the control device 11 determines control states Ci (with i = 0, 1,... N) for the valves 10.

The drive states Ci can be in particular Öffnungsstellun conditions of the valves 10.

The valves 10 are preferably steplessly stepless or at least in several stages. The flowing over the respective valve 10 coolant flow Wi can therefore according to the relationship be determined. In Equation 1, gi is a characteristic valid for the respective valve 10. The characteristic gi is a radio tion of the respective drive state Ci. It indicates for a nominal pressure pAO, how big at a certain Ansteuerzu Ci the current flowing over the respective valve 10 Kühlmit telstrom Wi each. This is shown purely by way of example in FIG. 3 for a single valve 10. The characteristic curves gi of the valves 10 can either be taken from data sheets of the manufacturer of the valves 10 or experimentally determined. In order to determine the respectively required control state Ci, the control device can, for example, solve equation (1) for Ci.

In a step S8, the controller 11 determines a pump pressure pP. The pump pressure pP is the pressure that should prevail on the output side of the pump 7, so that the input side of the valves 10, the working pressure pA is reached. When determining the pump pressure pP, the control device 11 takes into account at least the total coolant flow WG, the working pressure pA and the change 5W in the total coolant flow. telstroms WG. For example, the controller 11 may determine the pump pressure pP according to the relationship pP = pA + pH + pliVG) + p2 (βWG) (2). In Equation 2, pH is a (usually constant) pressure, which is caused by a height difference H. The height difference H is measured between the output side of the pump 7 and the outlets of the valves 10. The pressure pl describes a pressure drop that occurs due to the GE promoted total coolant flow WG on the way from the pump 7 to the valves 10. The pressure pl thus describes the line resistance of the line system 9. The pressure pl is a - usually non-linear - function of the total coolant flow WG. If necessary, additional resistances of the line system 9, such as, for example, filter resistances and the like, also enter the pressure pl.

The pressure p2 is a function of the change 5WG of the total coolant flow WG. It is calculated as follows:

For the acceleration of the coolant 3 in the line system 9, it is assumed below that the line system 9 has a cross section A uniform over its entire length L. If this is not the case, the following consideration must be made for the individual sections of the line system 9, each having a uniform cross section.

The amount of coolant 3 present in the line system 9 thus results in AL, the mass m of the coolant 3 to pAL, where p is the density of the coolant 3 (in the usual unit kg / m ³ ). The required acceleration a is 5WG / A. This results in the required force F to ma, ie the product of mass m and acceleration a supply. Thus, the required pressure p2 is F / A. Inserted into one another:

For this purpose, a numerical example: It is assumed that the line system 9 has a length L of 100 m and a cross-section A of 1 m ² . The coolant 3 is water. Within 1 second, the total coolant flow WG from 2 m ³ / s to 2.5 m ³ / s increases who the. Then a pressure p2 of 50 kPa is required for the required acceleration of the amount of water in the line 9.

After the determination of the required pump pressure pP, the control device 11 determines in a step S9 a supplied control state CP for the pump 7, so that the desired pump pressure pP is reached on the output side of the pump 7. The controller 11 takes into account the pump pressure pP, the total coolant flow WG and egg NEN suction pressure pS, the input side of the pump 7 prevails in the determination.

The suction pressure pS can be predetermined for the control device 11 or can be detected metrologically. It can, depending on the situation of the individual case, have a negative or a positive value or also the value 0. The controller 11 ver used to determine the drive state CP for the pump 7 preferably a pump curve. The pump characteristic sets the total coolant flow WG, the suction pressure pS on the input side of the pump 7 and the pump pressure pP on the output side of the pump 7 in relation to each other. The pump characteristic example, as shown in FIG 4 as Eingangsspara meter the total coolant flow WG and the difference between the pump pressure pP and suction pressure pS have and as Ausgangspa parameters provide the associated control state CP. At the control state CP can be in particular the speed of the pump 7. Such characteristics are well known to those skilled in the art.

After the determination of all activation states Ci, CP, the control device controls the valves 10 and the pump 7 in accordance with the ascertained activation states Ci, CP in a step S10. From step S10, the controller 11 returns to step S1. The controller 11 thus executes the steps S1 to S10 cyclically, the respective embodiment being valid for a particular time. Preferably ei ne strictly cyclical execution, ie there is a fixed stroke T, within which the steps S1 to S10 are processed once each Weil once. The power stroke T may be in example 0.1 seconds to 1.0 seconds, preferably between 0.2 seconds and 0.5 seconds, in particular re about 0.3 seconds.

In the simplest case, the controller 11 only the Nutz coolant flows Wi (i = 1, 2, ... n) for the respective

Timing and for temporally before the respective date lie ing dates known. Even in this case, the control device 11 can use the coolant flow W0 given from the bypass refrigerant outlet 6 to equalize the driving state CP of the pump 7. For this purpose, the control device 11, for example, a function F of the form begin. WG 'is the total coolant flow of the previous time. WO * is a predetermined coolant flow predetermined for the bypass coolant outlet 6. It is preferably about 30% to about 70% of the maximum coolant flow for the bypass coolant outlet 6, in particular about 50% of this value, a and ß are weighting factors. They are not negative. Furthermore, without limiting the generality, it can be demanded that the two weighting factors a, β add up to 1. The double strokes stand for a standard. The standard may in particular be the usual square standard. The coolant flows Wi for the Nutz coolant outlets 4 for the respective time are the controller 11 fixed. The function F thus has as the only freely selectable parameters parameter via the bypass coolant outlet 6 surrendering coolant flow WO. It is therefore possible to determine the minimum value of the function F and to use as the coolant flow W0 for the bypass coolant outlet 6 the value at which this minimum results. As a result, it is achieved that the coolant flow W0 to be discharged via the bypass coolant outlet 6 is as close as possible to the bypass desired coolant flow W0 * and the change in the total coolant flow WG is as low as possible.

If no coolant outlet 6 is present, the determination according to equation 4 does not make sense. In this case, the total coolant flow WG to be delivered results directly from the sum of the useful coolant flows Wi. If the dynamics of the pump Pum 7 is sufficient, a corresponding control of the pump 7 is readily possible, so that the total Ge to be conveyed coolant flow WG can be adjusted. However, if, despite a control of the pump 7 with a high dynamics, a change actually required can not be effected with sufficient speed, a temporary deviation of the actual total coolant flow conveyed by the pump 7 from a desired total coolant flow WG must be accepted.

Preferably, however, the control device 11 is not only the coolant flows for the respective time and - Bezo conditions at the respective time - for the past be known, but also for a forecast horizon PH projected Nutz coolant flows, ie those cooling medium flows, for a number be delivered from future times via the Nutz coolant outlets 4. This is shown in FIG. 5 for the respective resulting total coolant flows WG and a prognosis horizon PH of (purely by way of example) four working cycles T. The term "prognosis horizon" is furthermore not meant in the sense that far the controller 11 is actually a forecast be known. It depends only on how far the Steuereinrich device 11, the forecast in the context of determining the Ansteuerzu stands Ci, CP for the valves 10 and the pump 7 utilized. The forecast horizon PH may, for example, be in the range of 2 to 10 seconds. In general, he should correspond with a severely cyclical execution of the procedure of FIG 2 with several Ren working cycles T.

In the event that the control device 11, the prognos ticated useful coolant flows are known, the STEU ereinrichtung 11, the predicted useful coolant flows at least one of the future times in the determination of the drive state CO for the bypass coolant outlet 6 controlling valve 10 and / or the drive state CP of the pump 7 take into account. Here are various possibilities for consideration. Several of the possibilities are explained below.

In order to explain the procedure, the coolant flows are subsequently provided with two indices. The first index (i) is - as before - for the respective coolant outlet 4,

6. The second index (j) stands for the time, where a value j = 0 stands for the respective time, a value j = 1 for the subsequent time, etc. In an analogous manner, the total refrigerant flows with the second index (j ) Provided. For example, for the time indicated by the second index j = 2 Wi2 are the respective Kühlmit telströme for the individual coolant outlets 4, 6, while WG2 denotes the associated total coolant flow.

For example, it is possible for the control device 11 to determine the associated total coolant flow WGj (with j> 0) for at least one future time and to take into account this total coolant flow WGj when determining the change in the total coolant flow 5WG. In the corre sponding total coolant flow WGj may be in particular to act on the total coolant flow WG1 for the next time.

For example, the controller 11 for the respective time (j = 0) and the next time (j = 1) depending Weil as explained above, the function F optimie ren and thereby for the two mentioned times each associated overall coolant flow WG0, Determine WG1 and then on the basis of the relationship

WGl - WG0

SWG (5)

T determine the change in the total coolant flow 5WG. Preferably, however, the controller 11 further takes into account the total refrigerant flow WG 'of at least one past time in addition to the predicted useful refrigerant flows Wij of the at least one future time when determining the change 5WG of the total refrigerant flow. The respective time should lie in the middle between the at least one future time and the at least one past time. In particular, the control device 11 can determine the change 5WG of the total coolant flow WG on the basis of the relationship

WGl - WG '

SWG (6)

Determine 2T. The total coolant flow WG 'for the past time may alternatively be a desired value or an actual value. This is in contrast to the other variable variables used in the present case, which are always setpoints.

The procedure just explained will be explained in detail in connection Ver with FIG 6 again in detail. FIG. 6 includes, inter alia, analogously to FIG. 2, the steps S6 to S10. These steps will therefore not be explained again below. However, the steps S1 to S5 are replaced by steps Sil to S15.

In step Sil, the control device 11 - analogous to step S1 - for a respective time for the Nutz- coolant outlets 4 of the respective coolant flow WiO be known. In that regard, reference is made to the above statements to FIG 2. In addition, however, the control device 11 for later times, ie for times that are after the respective time, for the Nutz coolant outlets 4, the respective coolant flows Wij (with j = 1, 2, ... m) be known.

In step S12, the controller 11 determines the coolant flow W00. In particular, the coolant flow W00 results from the relationship

It is thereby achieved that with respect to the change 5WG of the total coolant flow WGO the prognosis of the previous cycle is maintained. It is thus achieved that the total cooling medium flow WGO of the current cycle coincides with the total coolant flow WG1 of the previous cycle. The total coolant flow predicted in the previous cycle is retained as is. This approach is in the context of FIG 6, in which to determine the change 5WG of the total cooling medium flow WGO only the total coolant flow WG1 of the next th cycle and the total coolant flow WG 'of the previous cycle are taken into account, sufficient. If required, analogous procedures can also be used for further total coolant flows WGj (with j> 1). In particular, the procedure can be used for each total coolant flow WGj taken in a previous cycle as part of determining the change valid for the respective cycle 5WG of the total coolant flow WGO was considered. Thus, the coolant flows WOj for the bypass Kühlmit telauslass 6 are adjusted in order to keep the total coolant flow WGj, which was utilized in the previous cycle, constant. Without Bypass Coolant Outlet 6, changes that occur in the short term may not be considered.

Furthermore, the control device 11 determines in step S12 for at least one power stroke T, for which the Steuereinrich device 11, the predicted Nutz coolant flows Wij be known, the associated bypass coolant flow WOj. As part of the concrete procedure of FIG. 6, the control device 11 can determine, for example, the bypass coolant flow W01 by minimizing the following equation 8:

The procedure is the same as that already explained above in connection with equation 4.

In a step S13, the controller 11 forms by summing the corresponding coolant streams Wij the ent speaking total coolant flows WGj.

In step S14, the controller 11 determines the change 5WG of the total refrigerant flow WG. The difference from step S4 of FIG. 2 is that the control device 11 uses the relationship indicated above in Equation 6 in step S14.

In step S15, the controller 11 updates the total refrigerant flow WG 'for the previous cycle. The difference to step S5 of FIG. 2 is that the control device 11 does not use the total coolant flow WGO of the current cycle in step S15, but rather the total coolant flow WG1, which it used to determine the change in 5WG of the total coolant flow WGO.

Another way to consider the prognostic ed Nutz coolant flows is explained below in connection with FIG.

As already explained above, determines the Steuerein device 11 - see in FIG 6, the step S13 - for each jewei time and after this time lying future time points each associated with the total coolant flow WGj. FIG. 7 shows this for a forecast horizon PH of four work cycles T. However, this forecast horizon PH is of course only an example. The forecast horizon PH could also be larger or smaller. The determined total coolant flows WGj are indicated in FIG. 7 by small crosses.

FIG 7 also shows the respective sum of the Nutz-Kühlmit telströme Wij. This determination is readily possible within the framework of the prognosis range PH, since the control device 11 knows the useful coolant flows Wij. The associated sums of the useful coolant flows Wij are indicated in FIG. 7 by small circles.

The control device 11 now further determines the associated changes in the total coolant flows WGj by forming the difference of directly consecutive total coolant flows WGj - for example, the total coolant flows WG1 and WG2. Then checks the controller 11 within the forecast horizon PH, whether the determined changes ments of the total coolant flows WGj each meet a vorbe agreed maximum change 5max or not. When the total refrigerant flows WGj maintain the maximum change 5max, the controller 11 maintains the detected total refrigerant flows WGj. On the other hand, if the total coolant flows WGj do not comply with the maximum change 5max, the control device 11 adapts the determined total coolant flows WGj in a forward-looking manner. The associated modified total Coolant streams WGj are shown in FIG 7 by small rectangles.

The adaptation is carried out as far as possible in such a way that both the change 5WG of the total coolant flow WGO for the respective time and the changes of the determined total coolant flows WGj for the future times comply with the maximum change 5max. This situation is shown in FIG.

If possible, the control device 11 keeps in the context of the adjustment for the various times given NEN Nutz coolant flows Wij and adjusts only the bypass coolant flows WOj. If it is not possible to achieve compliance with the maximum change 5max with an adaptation of only the bypass cooling medium flows WOj, however, an adaptation of the useful coolant flows Wij must also be undertaken. Without bypass coolant outlet 6 required adjustments must be made entirely by adjusting the Nutz-Kühlmit telströme Wij.

Thus, based on the prognosis, predictive planning can be anticipated. This can not only, as shown in FIG 7, be required for an increase in the requested total coolant flows WGj, but also at a reduction of the requested Gesamtmittels Kühlmittelströ me WGj.

As part of the procedure of FIG 2 - the same applies to the procedure of FIG 6 - the working pressure pA is set once in step S6 and is then no longer changed. However, it is possible to modify the procedure of FIG. 2 as explained below in connection with FIG. 8. An analogous modification is possible for the procedure of FIG.

According to FIG. 8, a step S21 is present between the steps S9 and S10. In step S21, the controller 11 checks whether the activation states Ci of the valves 10 comply with minimum distances to a minimum activation of the respective valve 10 and a maximum activation of the respective valve 10. Wei terhin checks the controller 11 in step S21, in wel chem extent the drive state CP of the pump 7 is changed wor the. For example, in the context of step S21, the control device 11 can set an optimization problem with boundary conditions to be observed. Such optimization problems are well known to those skilled in the art.

When the controller 11 determines in step S21 that the drive states Ci of the valves 10 keep the minimum distances and the drive state CP of the pump 7 is kept constant as much as possible, the controller 11 proceeds to step S10. Otherwise, the controller 11 proceeds to a step S22. In step S22, the control device 11 varies the scheduled Ar beitsdruck pA in terms of said optimization.

The pump 7 has an allowable operating range. In particular, the operation of the pump 7 according to the Dar position in FIG 9 only between a minimum speed nmin and a maximum speed nmax is permissible. Furthermore, the required amount of coolant - ie the respective total coolant flow WG - must be between a minimum allowable coolant flow WGmin and a maximum allowable coolant flow WGmax. The minimum allowable coolant flow WGmin and the maximum allowable coolant flow WGmax are hereby dependent on the representation in FIG. 9 of the difference between the pump pressure pP and the suction pressure pS. Without further measures, the pump 7 can therefore only be operated within half of the unhatched area in FIG.

However, it is possible to switch the pump 7 according to the presen- tation in FIG 10, a short-circuit valve 14 in parallel. Depending on the activation of the short-circuit valve 14, this makes it possible to dispense between 0% and 100% of the coolant flow conveyed by the pump 7 via the short-circuit valve 14. zuzweigen and return to the input side of the pump 7 or the Kühlmit telreservoir 8. As a result, only the remaining, non-recirculated portion remains as the total coolant flow WG. Thus, not only is it possible to operate the entirety of pump 7 and short-circuit valve 14 not only within the area unshaded in FIG. This would also be possible without the short-circuit valve 14. Rather, it is also possible because of the short-circuit valve 14, the totality of the pump 7 and short-circuit valve 14 to operate within the cross-hatched in FIG 9 area. The determination of a control signal CK for the short-circuit valve 14 can, for example, in the context of step S9 (see FIG 2 and FIG 6) take place. Of course, in this case a corresponding activation of the short-circuit valve 14 by the control device 11 takes place in step S10.

Preferably, in the case of the embodiment according to FIG. 10, a check is first made as to whether the pump 7 can be operated in a range that is permissible for itself. If this is the case, the short-circuit valve 14 remains (fully) closed. If this is not the case, the short-circuit valve 14 is opened as far as necessary to operate the pump 7 in a permissible range in itself.

The present invention has been explained above for a simple embodiment of the conduit system 9, as shown in FIG 1 for a single direct connection from the pump 7 to the valves 10, wherein the lengths of a individual stubs between a node 15 at which the Branch lines to the individual valves 10 depart, and the coolant outlets 4, 6 can be neglected.

However, the present invention is also applicable when the piping system 9 is made more complex. In this case, it merely has to be taken into account that, for each node point at which a branching occurs, the sum of the coolant flows flowing into the respective node point and flowing out from the respective node point totals 0. ben and that must be given at the respective node for each closed section of the line system 9, the same pressure. The procedure is analogous to the Kirchhoff rules of electrical engineering. Although the procedure becomes more computationally complicated, the systematics remains unchanged.

The system remains unchanged even if in individual NEN of the sections of the pipe system 9 own pumps are arranged. This will be explained in more detail below in conjunction with FIG 11 using an example.

According to FIG 11, the line system 9 three sections 16a, 16b, 16c. The section 16a extends from a Pum PE 7a to a node 15. It has the length La and the cross section Aa. From the node 15, the two other portions 16b, 16c extend to respective Nutz-Kühlmittelauslässen 4b, 4c and respective bypass Kühlmittelauslässen 6b, 6c. In the section 16b is located just behind the node 15, a further pump 7b. The section 16b has a length Lb and a cross section Ab. There is no pump in section 16c. The section 16c has a length Lc and a cross section Ac. The coolant outlets 4b, 4c and 6b, 6c are each preceded by valves 10b, 10c. The configuration shown in FIG 11 may, for example, occur at a cooling line, the egg nerseits intensive cooling (coolant outlets 4b) and additionally to a Laminarkühlung (coolant outlets 4c) and for each of the two coolings each bypass Bühlmittelaus let 6b, 6c. The hot rolling stock 3 and the arrangement of the Nutz-coolant outlets 4b, 4c in the cooling area 1 are not shown in FIG 11, th to 11 not überfrach.

The driving states Cic of the valves 10c in the section 16c are given in accordance with

As = gic (Cic) · -j pAc l pAO (9) How are the respective coolant flows, gic is the jewei time valve characteristic, pAc the input side of the valves 10c prevailing working pressure. pAO is, as already explained in connection with equation 1, a nominal pressure pAO. This results in the total coolant flow Wc for the section 16c

Wc = Wic (10) From this follows, neglecting to be overcome height differences for the pressure pl5 at the node 15: p \ 5 = pAc + plc {Wc) + p2c (öWc) (11) plc and p2c are analogous to the functions pl and p2 defi ned, but referred to the section 16c. 5Wc is the change of the total coolant flow Wc.

In an analogous manner, the drive states Cib of the valves 10b in the section 16b result

Wib = gib (db) · JpAb / pAO (12)

Wib are the respective coolant flows, gib is the respective valve characteristic, pAb is the working pressure prevailing on the input side of the valves 10b. As before, pAO is a nominal pressure pAO. This results in the total coolant flow Wb for the section 16b to Wb = _Wib (13)

From this follows - again neglecting to be overcome height differences - for the pump pressure pPb output side of the pump 7b: pPb = pAb + plb (Wb) + p2b {SWb) (14) p1b and p2b are defined analogously to the functions p1 and p2, but with reference to the section 16b. 5Wb is the change of the total coolant flow Wb. This also allows accordingly

CPb = CPb (Wb, pPb-p \ 5) (15) the required drive state CPb of the pump 7b can be determined.

The total coolant flow Wa flowing in section 16a is the sum of the total coolant flows Wb, Wc flowing in sections 16b and 16c: Wa = Wb + Wc (16)

As a result, the required pump pressure pPa on the output side of the pump 7a can now be determined on the basis of the relationship pPa = pl6 + pla (Wa) + p2a (SWa) (17), pla and p2a are defined analogously to the functions pl and p2, but to the section 16a based. Based on the pump pressure pPa can now by means of the relationship

CPa = CPa (Wa, pPa- pS) (18) the drive state CPa of the pump 7a are determined. Now, the working pressures pAb and pAc are target variables of the system, which can be predetermined or under certain circumstances also determined by the control device 11. The total cooling medium flows Wb, Wc are known. For the determination of the changes 5Wb, 5Wc (and consequently also the change 5Wa), reference may be made to the above statements in conjunction with FIGS. 2 and 6. The equation system is thus clearly solvable. Again, however, a realization without bypass coolant outlets 6b, 6c is possible again.

The present invention has many advantages. In particular, the required coolant flows Wi, WG are provided with high accuracy without requiring a water tank or other compensatory measures. The working pressure pA can be selected as needed and even adjusted during operation of the cooling section. The operating range of the cooling section will be expanded. In particular, after loading, both the suction pressure pS and the pump pressure pP may be biased. This applies both to pure laminar cooling and to pure intensive cooling as well as to a cooling section which comprises both laminar cooling and intensive cooling. Due to the adaptation of the working pressure pA and the pump pressure pP considerable energy can be saved. In a hot strip mill, the average energy consumption required to pump the coolant 2 can thereby be reduced by at least 30% over the prior art solutions, in some cases even by up to 50%. The associated cost savings can range well beyond € 100,000 a year. Furthermore, the process is extremely flexible. Within a few seconds, the total coolant flow WG can be increased from a minimum value to a maximum value or, conversely, reduced from the maximum value to the minimum value without the accuracy of the cooling suffers.

Although the invention has been illustrated and described in detail by the preferred Ausfüh approximately example, the invention is not limited by the disclosed examples, and other variants can be derived from the expert from this, without leaving the scope of the invention to ver. LIST OF REFERENCE NUMBERS

1 cooling area

2 coolants

3 rolling stock

4, 4b, 4c Nutz coolant outlets

5 rolling stand

5 'reel

6, 6b, 6c bypass coolant outlet

6 'collecting container

7, 7a, 7b pumps

8 coolant reservoir

9 pipe system

10, 10b, 10c valves

11 control device

12 computer program

13 machine code

14 short-circuit valve

15 node

16a, 16b, 16c sections of the conduit system

A, Aa, Ab, Ac Cross section of the line system Ci, Cib, Cic Control states of the valves CP, CPa, CPb Control states of pumps F Function

gi, gic, gic valve characteristics

H height difference

i r j indices

L, La, Lb, Lc length of the duct system nmin, nmax speeds

pl, pla to plc functions

p2, p2a to p2c

pl5 pressure

pA, pAb, pAc working pressures

pAO nominal pressure

PH forecast horizon

pP, pPa, pPb Pump pressures

pS suction pressure S1 to S22 steps

T work cycle

WG, WG ', WGj total cooling medium flows

Wgmin, Wgmax refrigerant flows

Wi, wo, Wij

WO * So11-Kühlmitteiström a, ß weighting factors

5WG, 5Wa, 5Wb, change of total coolant flow

5wc

5max maximum change

P Density of the coolant

Claims

claims

1. Operating method for a cooling section for cooling of hei ßem rolling stock (3) made of metal, wherein the cooling section comprises a pump (7) from a coolant reservoir (8) Kühlmit tel (2) extracts and a line system (9) a number from Kühlmittelauslässen (4, 6) which controls via the Kühlmit telauslässen (4, 6) upstream valves (10) who controlled,

- Wherein a control device (11) of the cooling section cyclically for a respective time

- Taking into account coolant flows (Wi), which are to be delivered at the respective time via the coolant outlets (4, 6), in connection with an input side of the valves (10) pending working pressure

(pA) of the coolant (2) determines activation states (Ci) for the valves (10),

- determined by summing the coolant flows (Wi) a total coolant flow (WG),

- Taking into account the total coolant flow (WG), the working pressure (pA) of the coolant (2) and additional Lich a change (5WG) of the total coolant flow (WG) determines a pump pressure (pP), the output side of the pump (7) prevail such that on the input side of the valves (10) the working pressure (pA) is reached,

- Taking into account the total coolant flow (WG), the pump pressure (pP) and an inlet side of the pump (7) prevailing suction pressure (pS) determines a drive state (CP) for the pump (7) and

- The valves (10) and the pump (7) according to the he averaged drive states (Ci, CP) controls.

2. Operating method according to claim 1,

characterized ,

in that the control device (11) takes into account, in the determination of the pump pressure (pP), a line resistance (p2) of the line system (9) to be overcome by the total coolant flow (WG).

3. Operating method according to claim 1 or 2,

characterized ,

that the control device (11) in addition to the coolant flow (Wij), which at the respective time via the cooling medium outlets (4, 6) to be delivered, for a

Forecast horizon (PH) are predicted coolant flows (Wij) to be delivered for a number of future times via the coolant outlets (4, 6), and that the controller (11) the predicted coolant flows (Wij) at least one of the future time points taken into account in determining the activation state (CP) of the pump (7).

4. Operating method according to claim 3,

characterized ,

the control device (11) determines the associated total coolant flow (WGj) for at least one future point in time and takes it into account when determining the change (5WG) of the total coolant flow (WGO).

5. Operating method according to claim 4,

characterized ,

that the control device (11) in the determination of the change (5WG) of the total coolant flow (WGO) in addition to the predicted coolant flows (Wij) of the at least one future time also continues to take into account the total coolant flow (WG ') of at least one past time point and that the respective time lies in the middle between the at least one future time and the at least one past time.

6. Operating method according to claim 4 or 5,

characterized ,

the coolant outlets (4, 6) comprise useful coolant outlets (4) and by-pass coolant outlets (6), - That the hot rolling stock (3) exclusively by means of the Nutz coolant outlets (4) emitted Kühlmittelströ me (Wij) is cooled,

- That the control device (11) based on the to be delivered for the respective time and / or the future times on the Nutz coolant outlets (4) Kühlmit telströmen (Wij) for the respective time and / or the future times on the bypass Kühlmittelaus Coolant streams (WiO) to be delivered (6) are such that each total flow of coolant (WGj) at an earlier point in time prior to the respective point in time is determined as part of the determination of the change (5WG) of the total flow of coolant ( WG) is maintained.

7. Operating method according to one of claims 3 to 6, d a d e c o v e n c e n e c e,

in that the control device (11) determines the state of control (CP) of the pump (7).

- For the future time points on the basis of the respective prog nostizierten coolant flows (Wij) a respective prog nostizierten total coolant flow (WGj) determined,

- For the future time changes of the determined total coolant flows (WGj) determined and

- For the respective time and / or future time points within the forecast horizon (PH), the respective total coolant flows (WGj) as a function of adhering to or exceeding a predetermined maximum change (5max) maintains or anticipated adapts, so that, if possible, both the change of the total coolant flow (WGO) for the respective time as well as the changes of the determined total coolant flows (WGj) for the future times the maximum change (5max).

8. Operating method according to claim 1 or 2,

characterized ,

the coolant outlets (4, 6) comprise useful coolant outlets (4) and by-pass coolant outlets (6), - That the hot rolling stock (3) exclusively by means of the Nutz coolant outlets (4) emitted Kühlmittelströ me (Wi) is cooled and

in that the control device (11) determines the coolant flows (WO) to be delivered via the bypass coolant outlets (6) such that the coolant flows (WO) to be delivered via the bypass coolant outlets (6) are as close as possible to a bypass target Coolant flow (WO *) are and a change (5WG) of about the Nutz coolant outlets (4) and the bypass coolant outlets (6) to be delivered total total coolant flow (WG) is minimized.

9. Operating method according to one of the preceding claims, d a d e r c h e c e n e c e n e,

the valves (10) can be controlled steplessly or at least in several stages.

10. Operating method according to one of the above claims, d a a c e c o v e c e s e c e n e,

the control device (11) determines the working pressure (pA) in such a way that the control states (Ci) of the valves (10) maintain minimum distances to a minimum control and a maximum control and the control state (CP) of the pump (7) as far as possible is kept constant.

11. Operating method according to one of the above claims, d a d u c h e c e n e c e n e,

in that the control device (11) additionally takes into account a height difference (H) to be overcome during the determination of the pump pressure (pP).

12. Operating method according to one of the above claims, d a d u c h e c e n e c e n e,

in that the control device (11) additionally determines a control signal (CK) for a short-circuit valve (14) connected in parallel with the pump (7) and actuates the short-circuit valve (14) accordingly to the determined control signal (CK).

13. Computer program, the machine code (13), which is executable by a control device (11) for a cooling line, the processing of the machine code (13) by the control device (11) causes the control device (11) the cooling section according to a Operating method according to one of the above claims operates.

14. Control device for a cooling section, wherein the control device is programmed with a computer program (12) according to claim 13, so that the control device operates the Kühlstre bridge according to an operating method according to one of claims 1 to 12.

15. Cooling section for cooling hot rolling stock (3) made of metal,

- wherein the cooling section comprises a pump (7) which takes from egg nem coolant reservoir (8) coolant (2) and via a line system (9) a number of Kühlmittelaus outlets (4, 6), which via the Kühlmittelauslässen (4,

6) upstream valves (10) are controlled,

- Wherein the cooling section has a control device (11) which operates the cooling section according to an operating method according to one of claims 1 to 12.

16. Cooling section according to claim 15,

characterized ,

a cooling region (1) of the cooling section, within which the coolant (2) is applied to the hot rolling stock (3), is arranged within a rolling train and / or arranged upstream of a rolling train and / or downstream of the rolling train.