Cooling device and cooling method

The present invention relates to a cooling device and a cooling method capable of controlling, by section, the flow of coolant supplied in a widthwise direction, the cooling device comprising: a base frame connected to an external cooling fluid supply line, and disposed to be able to spray coolant onto a material that passes through a rolling mill after having been heated in a heating furnace; and a nozzle assembly disposed on the base frame, and spraying a cooling fluid in an arbitrary pattern onto a plurality of sections divided along the widthwise direction of the material to minimize a deviation in temperature in the widthwise direction of the material. Through this configuration, the flow of coolant supplied in the widthwise direction of a material can be controlled to be varied, thereby being capable of minimizing a deviation in temperature in the widthwise direction of a high temperature material.

CROSS REFERENCE

This patent application is the U.S. National Phase under 35 U.S.C. § 371 of International Application No. PCT/KR2016/008206, filed on Jul. 27, 2016, which claims the benefit of Korean Patent Application No. 10-2015-0184745, filed on Dec. 23, 2015, the entire contents of each are hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a cooling device and a cooling method, and more particularly, to a cooling device and a cooling method in which a flow rate of coolant supplied in a width direction may be controlled in respective zones.

BACKGROUND ART

FIG. 1is a view schematically illustrating a general thick plate process line. Referring toFIG. 1, a material is led out from a heating furnace10in a high temperature state, passes through a widthwise rolling mill20and a lengthwise rolling mill30, and is preliminarily leveled in a preliminary leveler40, and is then accelerated and cooled in a cooling device50. In addition, the accelerated and cooled material passes through a hot leveler60and is shape-leveled, and is then cooled in a cooling bed70.

Here, the conventional cooling device50is configured to spray a predetermined amount of coolant in a width direction of the material, as illustrated inFIG. 2. However, when the predetermined amount of coolant is sprayed in the width direction of the material, since a central portion of the material has a smaller area in contact with the coolant than a volume thereof, a cooling effect in the central portion of the material is lowered, and since edge portions of the material have a wide area which is in contact with the coolant, the cooling effect at the edge portion of the material is increased. As a result, there is a problem in that a temperature deviation may occur throughout the material.

Further, to reduce temperature deviations in a length direction of the material, a technology has been performed for controlling a flow rate of coolant supplied to a head end portion (a), a central portion (b), and a tail end portion (c) of the material according to an indicated flow rate profile for a time illustrated inFIG. 3when the material is cooled. The above-mentioned technology tracks a position of the moving material and adjusts a flow rate of the corresponding position with a valve.

However, since the flow rate of coolant supplied to cool the material corresponds to several tons, there may be a problem in that it takes about 3 seconds to adjust the flow rate with the valve and it takes about 10 seconds or more to stabilize the supplied flow rate. Accordingly, since the flow rate of coolant sprayed to the material does not have time to accurately follow the set indicated flow rate profile, a large deviation in the flow rate of coolant which is actually supplied to the head end portion (a) and the tail end portion (c) may occur, resulting in a temperature deviation in the material.

DISCLOSURE

Technical Problem

An aspect of the present disclosure is to provide a cooling device and a cooling method, in which a flow rate of a coolant supplied in a width direction may vary to significantly reduce a temperature deviation with respect to a width direction of a high temperature material and to supply the coolant corresponding to a width of the material.

An aspect of the present disclosure is to provide a cooling device and a cooling method capable of significantly reducing the time required for operations of supplying and shutting off a flow rate to follow an indicated flow rate profile, to significantly reduce a temperature deviation occurring in a length direction of a high temperature material.

Technical Solution

According to an aspect of the present disclosure, a cooling device includes a base frame connected to an external cooling fluid supplying line and disposed to spray a coolant to a material which is heated in a heating furnace and then passes through a rolling mill; and a nozzle assembly disposed on the base frame and spraying a cooling fluid to a plurality of zones, divided in a width direction of the material, in any pattern to significantly reduce a temperature deviation in the width direction of the material.

The nozzle assembly may be disposed on the base frame to be supplied with the cooling fluid, nozzles may be formed in a plurality of rows and columns, a predetermined number of nozzles may form a group to be divided into a plurality of group nozzles, and the group nozzles may be opened and closed to spray the cooling fluid to predetermined zones.

The base frame may be disposed above a moving material, and the plurality of group nozzles of the nozzle assembly may be disposed in line to be parallel to the width direction of the material.

The nozzle assembly may selectively spray the cooling fluid to a specific zone in the width direction of the material by separately opening and closing the plurality of group nozzles.

The nozzle assembly may be provided to spray a flow rate of the cooling fluid sprayed in the width direction of the material to be different for each of the group nozzles by controlling the plurality of group nozzles to be separately opened and closed.

The nozzle assembly may be provided to discharge a predetermined amount of cooling fluid through group nozzles positioned at both ends among the plurality of group nozzles to prevent an occurrence of water hammering in zones in which the cooling fluid is stored and supplied.

The cooling device may further include a high-temperature material temperature sensor disposed upstream of the nozzle assembly and measuring a temperature in the width direction of the material which enters the nozzle assembly; and a controlling unit controlling the nozzle assembly to adjust a flow rate of the cooling fluid sprayed in the width direction of the material in response to temperature data in the width direction of the material received from the high-temperature material temperature sensor.

The cooling device may further include a cooled material temperature sensor disposed downstream of the nozzle assembly and measuring a temperature in the width direction of the material passing through the nozzle assembly, wherein the controlling unit controls the nozzle assembly by resetting the flow rate of the cooling fluid to be sprayed to the respective divided zones of the material in consideration of a temperature deviation when the temperature deviation in the width direction of the material received from the cooled material temperature sensor is higher than a predetermined temperature.

The base frame may include a support frame provided with the nozzle assembly; a storage pipe disposed on the support frame and connected to the cooling fluid supplying line to store the cooling fluid; and a supply pipe connecting between the nozzle assembly and the storage pipe to supply the cooling fluid to the nozzle assembly.

The nozzle assembly may include a housing in which the cooling fluid is stored; the plurality of nozzles provided to protrude to the inside of the housing and having through holes formed in a length direction to spray the cooling fluid to the outside; a plurality of masks disposed on the plurality of group nozzles to open and close each of the group nozzles; and a plurality of actuators disposed on the housing and separately moving the plurality of masks in a vertical direction.

The nozzle assembly may control a flow rate of the cooling fluid sprayed to the outside by adjusting an interval between the masks and the nozzles.

The mask may include a base plate in which a plurality of flow holes through which the cooling fluid flows are formed and having one side surface fastened to the actuator; and an elastic member disposed on the other side surface of the base plate, having holes formed in positions corresponding to the flow holes of the base plate, and sealing the through holes of the nozzles when the nozzles are closed.

The base plate of the mask may include a fastening part protruding from the center of one side surface thereof and fastened to the actuator; and a reinforcing rib extending from the fastening part to a circumference of the base plate to prevent a deformation of the base plate.

The reinforcing rib may include a plurality of first ribs extending from the fastening part to the respective corners of the base plate; and second ribs disposed on the plurality of first ribs and connecting between the plurality of first ribs.

The elastic member may further include a protrusion protruding from a portion which is closely in contact with the nozzle and pressurizing and sealing the nozzle.

The mask may be provided to be detached from the actuator.

The housing may include a penetrating part provided to be in communication with the outside and formed to have a size appropriate for the mask to be pulled out or inserted; and a door part opening and closing the penetrating part of the housing.

According to another aspect of the present disclosure, a cooling method includes a high-temperature material temperature measuring step of measuring a temperature in a width direction of a material which passes through a rolling mill and then enters a nozzle assembly; a spray flow rate setting step of dividing the material into predetermined zones in the width direction and setting a flow rate of a cooling fluid to be sprayed to the respective divided zones according to the temperature in the width direction of the material; and a coolant spraying step of separately spraying the cooling fluid to the respective divided zones of the material by controlling the nozzle assembly in which a plurality of group nozzles are formed in line in the width direction of the material.

In the spray flow rate setting step, to prevent an occurrence of water hammering in zones in which the cooling fluid is stored and supplied, a predetermined amount of cooling fluid may be set to be discharged through group nozzles positioned at both ends among the plurality of group nozzles.

The nozzle assembly may selectively spray the cooling fluid to a specific zone in the width direction of the material by separately opening and closing the plurality of group nozzles.

The nozzle assembly may be provided to control the plurality of group nozzles to be separately opened and closed, and spray the flow rate of the cooling fluid sprayed in the width direction of the material to be different for each of the group nozzles.

The cooling method may further include a cooled material temperature measuring step of measuring a temperature in the width direction of the material which passes through the nozzle assembly and is cooled, wherein when a temperature deviation in the width direction of the material measured in the cooled material temperature measuring step is higher than a predetermined temperature, a flow rate of the cooling fluid to be sprayed to the respective divided zones of the material is again set in the spray flow rate setting step in consideration of the temperature deviation.

Advantageous Effects

As set forth above, in a cooling device and a cooling method according to an exemplary embodiment in the present disclosure, since the flow rate of the coolant supplied in the width direction of the material maybe controlled to be varied, the temperature deviation in the width direction of the high temperature material may be significantly reduced.

In addition, according to an exemplary embodiment, a nozzle opening and closing means may be provided to improve an opening and closing response speed of the nozzle, and the coolant may be simultaneously sprayed through a plurality of nozzles to quickly stabilize the sprayed flow rate of the coolant, thereby stably following the indicated flow rate profile.

BEST MODE FOR INVENTION

To facilitate understanding of the features of the present disclosure, hereinafter, a cooling device and a cooling method according to exemplary embodiments in the present disclosure will be described in more detail.

It is to be noted that in giving reference numerals to components of each of the accompanying drawings to facilitate understanding of exemplary embodiments to be described below, the same components will be denoted by the same reference numerals even though they are shown in different drawings. Further, in describing exemplary embodiments in the present disclosure, well-known configurations or functions will not be described in detail since they may obscure the subject matter of the present disclosure.

Hereinafter, exemplary embodiments in the present disclosure will be described with reference to the accompanying drawings.

FIG. 4is a perspective view schematically illustrating a cooling device according to an exemplary embodiment in the present disclosure andFIG. 5is a perspective view schematically illustrating a plurality of group nozzles in the cooling device.FIG. 6is a front view schematically illustrating an operating state of the cooling device andFIG. 7is a block diagram schematically illustrating the cooling device.FIG. 8is an enlarged perspective view schematically illustrating one portion of the cooling device andFIG. 9is a perspective view schematically illustrating a mask extracted from the cooling device.FIGS. 10 and 11are cross-sectional views schematically illustrating states in which a nozzle is closed and opened in the cooling device andFIGS. 12 and 13are views schematically illustrating state in which a cooling fluid moves through a flow hole of a mask when the nozzle is opened and closed in the cooling device.

Referring toFIGS. 2 through 13, a cooling device100according to an exemplary embodiment in the present disclosure may include a base frame200connected to an external cooling fluid supplying line10and disposed to spray a coolant to a material M which is heated in a heating furnace and then passes through a rolling mill, and a nozzle assembly300disposed on the base frame200and spraying the cooling fluid to a plurality of zones Z, divided in a width direction of the material, in any pattern to significantly reduce a temperature deviation in the width direction of the material M.

The nozzle assembly300may be disposed on the base frame200to be supplied with the cooling fluid, nozzles320may be formed in a plurality of rows and columns, a predetermined number of nozzles320may form a group to be divided into a plurality of group nozzles G, and the group nozzles G may be opened and closed to spray the cooling fluid to predetermined zones.

That is, a plurality of nozzles320may be provided and a predetermined number of nozzles320may be grouped into the group nozzle G. Since the cooling fluid may be simultaneously sprayed to predetermined zones Z by simultaneously opening the predetermined number of nozzles320, a supplied flow rate may be stabilized within a relatively fast time, thereby stably following an indicated flow rate profile. Here, the cooling fluid may be provided as a coolant, and may be provided to cool a high-temperature material by free-falling onto the high-temperature material due to self weight when the nozzles320are opened.

In addition, the nozzle assembly300may be provided to selectively spray the cooling fluid to a specific zone Z by opening at least one group nozzle G of the plurality of group nozzles G.

More specifically, in a case in which the nozzle assembly300is disposed in a width direction of the high-temperature material M and the group nozzles G of the nozzle assembly300are disposed in line in the width direction of the high-temperature material M, the nozzle assembly300may be provided to cool only a specific zone Z of the high-temperature material M by selectively opening a specific group nozzle of the plurality of group nozzles G.

For example, as illustrated inFIG. 6, in a case in which ten group nozzles are disposed, the nozzle assembly300may be operated to spray the cooling fluid by closing second, fourth, seventh, and ninth group nozzles and opening first, third, fifth, sixth, eighth, and tenth group nozzles from the left in the drawing.

According to the above-mentioned configuration, since the cooling fluid may be selectively sprayed to the specific zone in the width direction of the high-temperature material M, a temperature deviation in the width direction may be significantly reduced. That is, the nozzle assembly300is operated so that a large amount of cooling fluid may be sprayed to high-temperature zones in the high-temperature material M in which the large amount of cooling fluid needs to be sprayed by opening two or three group nozzles of positions corresponding to the high-temperature zones, and is operated so that a relatively small amount of cooling fluid is sprayed to a relatively low-temperature zone by opening one group nozzle or the cooling fluid is not sprayed to the relatively low-temperature zone by closing the group nozzles, thereby significantly reducing the temperature deviation in the width direction.

Further, the first and tenth group nozzles positioned at both ends among the plurality of group nozzles may be always opened while the cooling device is operated so that a predetermined amount of cooling fluid is discharged to prevent an occurrence of water hammering in zones in which the cooling fluid is stored and supplied.

In addition, the cooling device100according to an exemplary embodiment in the present disclosure may include a high-temperature material temperature sensor420disposed upstream of the nozzle assembly300and measuring a temperature in the width direction of the material which is heated in the heating furnace, passes through the rolling mill (R), and then enters the nozzle assembly300, and a controlling unit410controlling the nozzle assembly300to adjust a flow rate of the cooling fluid sprayed in the width direction of the material in response to temperature data in the width direction of the material M received from the high-temperature material temperature sensor420.

That is, the temperature in the width direction of the material M may be measured by the high-temperature material temperature sensor420before the material M enters the nozzle assembly300, and the controlling unit410may control the nozzle assembly300so that a large flow rate of cooling fluid is sprayed to a zone having a relatively high temperature and a small flow rate of cooling fluid is sprayed to a zone having a relatively low temperature, based on the temperature data in the width direction of the material M.

Further, the cooling device100may further include a cooled material temperature sensor430disposed downstream of the nozzle assembly300and measuring a temperature in the width direction of the material M passing through the nozzle assembly300.

In this case, if the temperature deviation in the width direction of the material M received from the cooled material temperature sensor430is higher than a predetermined temperature, that is, a temperature deviation range that the material has to satisfy, the controlling unit410may control the nozzle assembly300by resetting a flow rate of the cooling fluid to be sprayed to the respective divided zones of the material M in consideration of the temperature deviation.

According to the above-mentioned configuration, the flow rate of the cooling fluid sprayed to the respective zones may be primarily set through the data measured from the high-temperature material temperature sensor420online, and in a case in which the data measured from the cooled material temperature sensor430is received, if the temperature deviation in the width direction of the material is a predetermined temperature or more, the flow rate of the cooling fluid sprayed to the respective zones may be secondarily adjusted. Thereby, an optimal spray flow rate of the cooling fluid capable of significantly reducing the temperature deviation of the material M may be set.

The base frame200may include a support frame210provided with the nozzle assembly300, a storage pipe220disposed on the support frame210and connected to the cooling fluid supplying line10to store the cooling fluid, and a supply pipe230connecting between the nozzle assembly300and the storage pipe220to supply the cooling fluid to the nozzle assembly300.

That is, the storage pipe220may be connected to the cooling fluid supplying line10to be supplied with the cooling fluid, and may be formed to store a larger amount of cooling fluid than an amount of cooling fluid stored in the nozzle assembly300in advance to smoothly supply the cooling fluid to the nozzle assembly300. In addition, the supply pipe230may include a valve (not shown) to supply the cooling fluid when the cooling fluid stored in the nozzle assembly300becomes a predetermined amount or less.

The nozzle assembly300may include a housing310in which the cooling fluid is stored, a plurality of nozzles320provided to protrude to the inside of the housing310and having through holes formed in a length direction to spray the cooling fluid to the outside, a plurality of masks330disposed on the plurality of group nozzles to open and close each of the group nozzles, and a plurality of actuators340disposed on the housing310and separately moving the plurality of masks330in a vertical direction.

The housing310may have a hollow portion to store a predetermined amount of cooling fluid or more therein, and may have a horizontal lower side surface on which the plurality of nozzles320are formed.

In addition, the housing310may be elongated so that the group nozzles are disposed in line. In this case, the housing310may be disposed in the width direction of the high-temperature material to selectively open the plurality of group nozzles, thereby supplying the cooling fluid to a specific zone in the width direction.

The nozzles320may be provided in a plurality of rows and columns in the housing310to spray the cooling fluid to a predetermined zone. In addition, the nozzles320may protrude to the inside of the housing310from the lower side surface of the housing310, and have the through holes formed in the length direction to spray the cooling fluid to the outside. That is, in a case in which the masks330close the nozzles320, the masks may close the nozzles by pressurizing end portions of the protruding nozzles320. Thereby, water leak of the cooling fluid may be more effectively prevented. A shape of the nozzles320is not limited thereto, and the nozzles320may also be provided in any form in which the cooling fluid may be simultaneously sprayed to the predetermined zone.

In addition, the plurality of nozzles320may be divided into a plurality of group nozzles by forming a predetermined number of nozzles as a group. For example, in a case in which the nozzles320is formed in eight rows and eighty columns in the housing310, if eight nozzles320in a vertical direction and eight nozzles320in a horizontal direction are formed as one group nozzle, the nozzles320may be divided into a total of ten group nozzles. In this case, the masks330may be provided to simultaneously open and close one group nozzle, that is, the eight nozzles320in the vertical direction and the eight nozzles320in the horizontal direction.

The masks330may be disposed inside the housing310to be moved vertically, and operate to simultaneously open and close the plurality of nozzles320protruding to the inside of the housing310, that is, one group nozzle to simultaneously spray or block the cooling fluid through the plurality of nozzles320. In this case, the masks330maybe moved vertically by the driving of the actuators340disposed on the housing310. In a case in which the nozzles320are opened by moving the masks330in a state in which the nozzles320are closed, the flow rate of the sprayed cooling fluid may also be controlled by adjusting an interval between the masks330and the nozzles320.

More specifically, the mask330may include a base plate331in which a plurality of flow holes h through which the cooling fluid may flow is formed and having one side surface fastened to the actuator340, and an elastic member332disposed on the other side surface of the base plate331, having holes formed in positions corresponding to the flow holes h of the base plate331, and sealing the through holes of the nozzles320when the nozzles320are closed.

The base plate331may be formed to have an area capable of covering the entire of the plurality of nozzles320disposed on the housing310. To significantly reduce resistance due to the cooling fluid when base plate331is moved vertically, the flow holes h may be formed in regions of the base plate331other than regions for closing the nozzles320. That is, when the base plate331having a predetermined area is moved in a vertical direction in the housing310, large resistance due to the cooling fluid occurs by a wide surface area of the base plate331. As a result, a respond for a control signal is delayed and it is difficult to follow the indicated flow rate profile. Therefore, to secure a rapid response speed, the flow resistance caused when the base plate331is moved vertically may be significantly reduced by forming the plurality of flow holes h.

In a case in which the nozzles320are opened by moving the base plate331upwardly in a state in which the nozzles320are closed, as illustrated inFIG. 12, since a large amount of cooling fluid may flow through the plurality of flow holes h formed in the base plate331, the resistance applied to the base plate331may be reduced, thereby significantly reducing deformation of the base plate331. In addition, even in a case in which the base plate331is moved to close the nozzles320after a predetermined time, as illustrated inFIG. 11, since a large amount of cooling fluid may flow through the plurality of flow holes h, the resistance applied to the base plate331may be reduced.

In addition, the base plate331of the mask330may include a fastening part333protruding from the center of one side surface thereof and fastened to the actuator340, and a reinforcing rib334extending from the fastening part333to a circumference of the base plate331to prevent the deformation of the base plate331.

That is, in the base plate331having the wide surface area, since bending deformation occurs at four ends of the front and back, right and left around the fastening part333when being moved vertically, there is a possibility that a fatigue load is accumulated on the base plate331and the base plate is broken when the base plate331is used for a long time. Therefore, the base plate may be reinforced with respect to a bending load by forming the reinforcing rib334to extend from the fastening part333formed at the center of the base plate331to the circumference of the base plate331. In this case, the reinforcing rib334may be welded and fastened to the fastening part333and one side surface of the base plate331.

Further, in a case in which the masks330are disposed in line in the housing310to open and close the nozzles320, the reinforcing rib334maybe formed on the base plate331in the same direction as the direction in which the masks330are disposed. That is, when the masks330are moved vertically, the cooling fluid in the housing310is pushed to both sides by the movement of the masks330, and the pushed cooling fluid is applied to an adjacent mask330as a large load to thereby cause breakage of the adjacent mask330. Therefore, a region of the base plate331on which the load is concentrated may be reinforced by forming the reinforcing rib334in the same direction as the direction in which the masks330are disposed.

FIGS. 14 and 15are cross-sectional views schematically illustrating state in which the nozzle is closed and opened using a mask according to another exemplary embodiment in the cooling device.

Referring toFIGS. 14 and 15, the elastic member332of the mask330may further include a protrusion332aprotruding on a portion which is closely in contact with the nozzle320and pressurizing and sealing the nozzle320. That is, the elastic member332may include the protrusion332aprotruding to the nozzle320from a region which is closely in contact with the nozzle320, and may seal the nozzle320so that the cooling fluid is not leaked when the nozzle320is closed. In this case, the protrusion332amay have a diameter at least larger than the diameter of the nozzle320.

FIG. 16is a perspective view schematically illustrating a mask according to another exemplary embodiment extracted from the cooling device.

Referring toFIG. 16, the reinforcing rib334provided on the base plate331may also include a plurality of first ribs334aextending from the fastening part to the respective corners of the base plate331, and second ribs334bdisposed on the plurality of first ribs334aand connecting between the plurality of first ribs334a,to support the deformation of the base plate331with higher rigidity. Of course, the shape and structure of the reinforcing rib334are limited thereto, and the reinforcing rib334may also be provided in any form in which a phenomenon in which the base plate331is bent may be prevented.

FIG. 17is a state view schematically illustrating a state in which the mask is replaced in the cooling device andFIG. 18is a view schematically illustrating a state in which the mask is detached from the cooling device.

Referring toFIGS. 17 and 18, the mask330may be provided to be detached from the actuator340. That is, the fastening part333formed on the base plate331and an action rod of the actuator340may be provided to be detached from each other. This is to easily replace only the mask330when the mask330may not accurately open and close the nozzle320due to the deformation of the base plate331or corrosion of the elastic member332according to a use for long period of time. In this case, the actuator340and the fastening part333are fastened to each other by a pin360as illustrated inFIG. 17, such that the actuator340and the fastening part333may be more simply fastened to and separated from each other. Of course, the configuration for detaching the actuator340and the base plate331from each other is not limited thereto, and various mechanical methods may be used.

To this end, the housing310may further include a penetrating part311provided to be in communication with the outside and formed to have a size in which the mask330may be pulled out or inserted, and a door part350opening and closing the penetrating part311of the housing310. That is, the door part350may close the penetrating part311of the housing310, and may open the inside of the housing310by opening the door part350when it is necessary to check an inside state of the housing310or replace the mask330. In this case, the door part350may be provided to open and close the penetrating part311by being rotatably fastened to the housing310, or to open and close the penetrating part311by being provided to be detached from the penetrating part311.

FIG. 19is a flowchart schematically illustrating a cooling method according to an exemplary embodiment in the present disclosure.

Referring toFIG. 19, a cooling method may include a high-temperature material temperature measuring step (S110) of measuring a temperature in a width direction of a material which passes through a rolling mill and then enters a nozzle assembly, a spray flow rate setting step (S120) of dividing the material into predetermined zones in the width direction and setting flow rate of a cooling fluid to be sprayed to the respective divided zones according to the temperature in the width direction of the material, and a coolant spraying step (S130) of separately spraying the cooling fluid to the respective divided zones of the material by controlling the nozzle assembly in which a plurality of group nozzles are formed in line in the width direction of the material.

In addition, the cooling method may further include a cooled material temperature measuring step (S140) of measuring a temperature in the width direction of the material which passes through the nozzle assembly and is cooled, wherein when a temperature deviation in the width direction of the material measured in the cooled material temperature measuring step (S140) is higher than a predetermined temperature, that is, a temperature deviation range that the material has to satisfy (Yes in S150), a flow rate of the cooling fluid to be sprayed to the respective divided zones of the material may be again adjusted by returning to the spray flow rate setting step (S120) in consideration of the temperature deviation.

According to the above-mentioned method, the flow rate of the cooling fluid sprayed to the respective zones may be primarily set through data measured from the high-temperature material temperature step (S110) online, and if the temperature deviation in the width direction of the material is more than the predetermined temperature through the data measured from the cooled material temperature measuring step (S140), the flow rate of the cooling fluid sprayed to the respective zones may be secondarily adjusted. Thereby, an optimal spray flow rate of the cooling fluid capable of significantly reducing the temperature deviation of the material may be set.

Here, in the spray flow rate setting step (S120), to prevent an occurrence of water hammering in zones in which the cooling fluid is stored and supplied, a predetermined amount of cooling fluid may be set to be discharged through group nozzles positioned at both ends among the plurality of group nozzles.

In addition, the nozzle assembly may be configured to selectively spray the cooling fluid to a specific zone in the width direction of the material by separately opening and closing the plurality of group nozzles.

In addition, the nozzle assembly may be provided to control the plurality of group nozzles to be separately opened and closed, and may spray the flow rate of the cooling fluid sprayed in the width direction of the material to be different for each of the group nozzles.

As described above, although the present disclosure has been described with reference to exemplary embodiments and the accompanying drawings, it would be appreciated by those skilled in the art that the present disclosure is not limited thereto, but various modifications and alterations might be made without departing from the scope defined in the following claims.