JP2019014918A - Cooling device of metallic strip - Google Patents

Abstract

To provide a cooling device for a metallic strip where, while making cooling equipment compact in such a manner that the length in the jetting direction of a refrigerant obtained by summing up a header pipe through which the refrigerant flows and a nozzle jetting the refrigerant is made short, the highness of the jet speed of the refrigerant from the nozzle till it strikes against a metallic strip is maintained as possible, and the cooling speed of the metallic strip is improved to perform uniform cooling.SOLUTION: Provided is a cooling device 1 for a metallic strip comprising: a header pipe 10 through which a refrigerant flows; and a nozzle 11 provided at the header pipe 10 and jetting the refrigerant from the header pipe 10, and cools a running metallic strip S with the refrigerant jetted from the nozzle 11. The nozzle 11 comprises: a refrigerant run-up section formation part 11a fitted to an opening 10a formed at the header pipe 10 so as to be built in the header pipe 10 and running up the refrigerant from the inside of the header pipe 10; and an opening part 1b formed at the outlet of the refrigerant run-up section formation part 11a and jetting the refrigerant run up at the inside of the refrigerant run-up section formation part 11a to the outside of the header pipe 10.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a cooling device for a metal strip, and more particularly to a device for cooling a continuously running steel strip in a continuous annealing facility, a continuous hot-dip galvanizing facility, a resin coating facility, or the like of a steel strip.

  As is well known, continuous annealing equipment includes a step of continuously heating, soaking and cooling a steel strip, which is a kind of metal strip, and if necessary, an overaging treatment. By the way, in order to obtain the desired properties of the steel strip, it is important to uniformly cool the steel strip in addition to the heating temperature and the soaking temperature. Various types of refrigerants are currently used as a method for cooling the steel strip, and the cooling rate of the steel strip varies depending on the selection of this refrigerant.

  Here, a cooling method using gas (gas) as a refrigerant has been put into practical use, and many achievements have been given. This method enables relatively uniform cooling in the width direction of the steel strip. A general problem of this gas cooling is that the cooling rate is slow compared with a cooling method using water as a refrigerant. If the cooling rate is slow, the properties of the steel strip will not be as desired. In order to increase the cooling rate, conventionally, for example, there has been proposed a method in which the tip of a nozzle for injecting gas is brought as close as possible to a steel strip to increase the heat transfer rate and increase the cooling rate (see Patent Document 1).

In the strip cooling device in the continuous annealing path shown in Patent Document 1, the distance Z between the strip and the nozzle tip is set to 70 mm or less, and the protruding length of the nozzle from the front surface of the cooling gas chamber is set to (100−Z) mm or more. The distance between the tip and the strip is reduced to enable efficient cooling.
Also, in order to obtain a high cooling rate, the gas ejection speed from the nozzle is increased, the resistance coefficient of the nozzle is reduced, the gas circulation facility is made compact, and the heat transfer coefficient by the refrigerant ejected from the nozzle is increased to achieve uniform cooling. As a steel strip cooling device that can be used, for example, the one shown in Patent Document 2 has been proposed.

  In the steel strip cooling device shown in Patent Document 2, a projecting nozzle is arranged on the surface of a cooling box, and a steel strip cooling device that cools a traveling steel strip by ejecting refrigerant from the projecting nozzle. A plurality of protruding nozzles that maintain a distance to the belt surface of 30 to 100 mm are protruded from the surface of the cooling box, and A / a of the protruding nozzles is 2 ≦ A / a ≦ 9 (A: opening cross-sectional area of nozzle base, a : The opening sectional area of the nozzle tip), the distance from the surface of the cooling box to the nozzle tip of the protruding nozzle is 150 to 200 mm, and the flatness a1 / a2 of the opening section of the nozzle tip is 1 <a1 / a2 < 9 (a1: long side of the opening cross section of the nozzle tip, a2: short side of the opening cross section of the nozzle tip).

  According to the steel strip cooling device shown in Patent Document 2, it is possible to increase the heat transfer coefficient in cooling and cool the steel strip uniformly. Even if the gas ejection speed from the nozzle is increased in order to obtain a high cooling rate, the resistance coefficient of the nozzle can be reduced, and the gas circulation facility can be made compact.

Japanese Patent Publication No. 2-16375 JP 2006-274379 A

However, the conventional strip cooling device shown in Patent Document 1 and the steel strip cooling device shown in Patent Document 2 have the following problems.
That is, in the case of the strip cooling apparatus shown in Patent Document 1, since the nozzle protrudes from the front surface of the cooling gas chamber through which the refrigerant flows through a protrusion length (100-Z) mm or more, the refrigerant is jetted out of the cooling gas chamber and the nozzle. The length of the direction is long and the equipment cannot be made compact.

Similarly, in the case of the steel strip cooling device shown in Patent Document 2, the protruding nozzle protrudes from the surface of the cooling box through which the refrigerant flows, and the length of the cooling direction of the refrigerant combined with the cooling box and the protruding nozzle is long. Long and the equipment cannot be made compact.
Therefore, the present invention has been made to solve this conventional problem, and its purpose is to shorten the length of the refrigerant in the jetting direction by combining the header pipe through which the refrigerant flows and the nozzle from which the refrigerant is jetted. A cooling device for a metal strip capable of performing uniform cooling by improving the cooling speed of the metal strip while maintaining the high speed as much as possible until the coolant jet speed from the nozzle hits the metal strip while making the cooling equipment compact. There is.

  In order to achieve the above object, a metal band cooling device according to an aspect of the present invention includes a header pipe through which a refrigerant flows, and a nozzle that is provided in the header pipe and ejects the refrigerant from the header pipe. A metal band cooling device that cools a traveling metal band by a refrigerant jetted from the nozzle, wherein the nozzle is attached to an opening formed in the header pipe so as to be incorporated in the header pipe. The refrigerant run-up section forming portion for running the refrigerant from the inside of the header pipe, and the refrigerant that has run through the inside of the refrigerant run-up section forming section to the outside of the header pipe The gist of the invention is that it includes an opening to be ejected.

  According to the metal belt cooling device of the present invention, the refrigerant from the nozzle is reduced while shortening the length of the refrigerant jetting direction by combining the header pipe through which the refrigerant flows and the nozzle for jetting the refrigerant, thereby reducing the cooling equipment. It is possible to provide a metal strip cooling device capable of performing uniform cooling by maintaining a high speed as much as possible until the ejection speed hits the metal strip and improving the cooling rate of the metal strip.

It is a schematic block diagram of the cooling device of the metal strip which concerns on one Embodiment of this invention. FIG. 2 is a cross-sectional view schematically showing a header pipe and a nozzle portion together with a steel strip S in the cooling device shown in FIG. 1. FIG. 2 is a cross-sectional bird's-eye view schematically showing a header pipe and a nozzle portion in the cooling device shown in FIG. 1. It is the expanded view which looked at the header pipe | tube and nozzle part shown in FIG.2 and FIG.3 from the inside of the header pipe | tube. It is a figure for demonstrating the cross section and line 5-5 in FIG. 4, and the discharge flow velocity distribution of a refrigerant | coolant. It is the expanded view which looked at the header pipe | tube and nozzle part of the cooling device which concerns on a 1st reference example from the inside of a header pipe | tube. It is a figure for demonstrating the cross section in alignment with line 7-7 in FIG. 6, and the discharge flow velocity distribution of a refrigerant | coolant. It is the expanded view which looked at the header pipe | tube and nozzle part of the cooling device which concerns on a 2nd reference example from the inside of the header pipe | tube. It is a figure for demonstrating the cross section and line 9-9 in FIG. 8, and the discharge flow velocity distribution of a refrigerant | coolant. It is sectional drawing of the header pipe | tube and nozzle of the cooling device which concerns on a 1st modification. It is a cross-sectional bird's-eye view of the header pipe | tube and nozzle of the cooling device which concerns on a 2nd modification.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A metal strip cooling device 1 shown in FIG. 1 is a steel strip that runs continuously in a continuous annealing facility for a steel strip S as a metal strip (in FIG. 1, steel that runs continuously from top to bottom). A plurality of pairs each provided with a plurality of nozzles 11 so as to eject air as a refrigerant from the front surface side (left side in FIG. 1) and the back surface side of the traveling steel strip S. The header pipe 10 is provided on the front side and the back side of the steel strip S. The header pipes 10 on the front side and the back side of the steel strip S are arranged at a predetermined pitch in the vertical direction.

Here, the air as the refrigerant cools the front and back surfaces of the steel strip S that flows through the header pipes 10 and is jetted from the nozzles 11 and travels, and is reused through the circulation system.
In other words, the air that has cooled the front and back surfaces of the steel strip S is introduced into the refrigerant passage 20a of the heat exchanger 20 and is cooled by the factory water flowing through the water passage 20b, and is passed through the refrigerant first introduction pipe 21. The refrigerant is sucked by the blower 22 and reaches the refrigerant branch pipe 24 via the refrigerant second introduction pipe 23 connected to the blower 22. The air reaching the refrigerant branch pipe 24 is bifurcated by the refrigerant branch pipe 24 in the direction in which the header pipe 10 extends. The bifurcated air reaches the vertical pipes 26 through the pipes 25, flows from the vertical pipes 26 through the front side introduction pipes 27 from both ends of the header pipe 10 on the surface side, and flows into the header pipes 10 respectively. The vertical pipe 26 flows through the header pipe 10 from both ends of the header pipe 10 on the back side through the pipe 28 and the back side introduction pipe 29. And the air which flows through the header pipe | tube 10 of the surface side and the back surface side is ejected toward the surface and back surface of the steel strip S from each nozzle 11 provided in each header pipe | tube 10. FIG.

  Here, as shown in FIGS. 2 and 3, each header pipe 10 is a cylindrical tubular member having a double circular cross section, and as shown in FIG. 1, is elongated in the same direction as the width direction of the traveling steel strip S. It extends. As shown in FIGS. 2 to 5, a plurality of openings 10 a are formed at a predetermined pitch on the side surface of each header pipe 10 facing the steel strip S along the direction in which each header pipe 10 extends. Yes. Each opening 10 a is formed by a round hole penetrating the header tube 10.

  Further, as shown in FIGS. 2 to 5, each nozzle 11 is attached so as to be incorporated in the header pipe 10 in a round hole constituting each opening 10 a formed in each header pipe 10. Each nozzle 11 is a cylindrical tubular member, and is formed at a refrigerant run-up section forming portion 11a for running the refrigerant from the inside of the header pipe 10 and an outlet of the refrigerant run-up section forming portion 11a. And an opening 11b that ejects air as refrigerant that has run through the header pipe 10 to the outside.

Thus, since each nozzle 11 is provided with the refrigerant run-up section forming portion 11a, the turbulent flow in the nozzle 11 is developed, the straightness of the jet ejected from the nozzle 11 is increased, and the potential core (the center of the jet) The sustained distance of the high-speed flow area of the part becomes longer. FIG. 5 shows the discharge flow velocity distribution of air (refrigerant), and the flow velocity of the air discharged from the nozzle 11 becomes slower from the nozzle 11 toward the steel strip S as the distance from the nozzle 11 increases. The flow rate of the part gradually decreases from V ₁ to V ₂ , V ₃ , V ₄ . However, by the nozzle 11 is provided with a refrigerant inlet zone forming portion 11a, since the straightness of the jet ejected from the nozzle 11 is increased, it is different from the flow velocity V ₁ and V ₄ of the center of the jet The amount of deceleration of the flow rate is small. Thereby, the heat transfer coefficient of the front and back of the steel strip S to cool increases. That is, the cooling speed of the steel strip S is improved by maintaining the high speed as much as possible until the coolant ejection speed from each nozzle 11 hits the steel strip S. Thereby, uniform cooling of the steel strip S can be performed.

On the other hand, since each nozzle 11 is built in the header pipe 10, the length of the air ejection direction combining the header pipe 10 through which air as a refrigerant flows and the nozzle 11 that ejects air is shortened to provide cooling equipment. Can be made compact.
Therefore, according to the cooling device 1 according to the present embodiment, while the length of the air jet direction in which the header pipe 10 through which the air flows and the nozzle 11 that jets the air is combined is shortened to make the cooling facility compact, The cooling speed of the steel strip S can be kept as high as possible until the refrigerant ejection speed from the steel 11 hits the steel strip S, and the cooling speed of the steel strip S can be improved to perform uniform cooling.

Note that the size of the diameter D (see FIG. 5) of the opening 11b of the nozzle 11 is not particularly specified, and the length L of the nozzle 11 from the inner surface of the header tube 10 to the inside is longer than zero. That's fine.
Next, the air discharge flow rate distribution by the cooling device according to the first reference example will be described with reference to FIGS.

  As shown in FIGS. 6 and 7, the header pipe 100 of the cooling device according to the first reference example is a cylindrical tubular member having a double-circular cross section, and is elongated in the same direction as the width direction of the traveling steel strip S. Yes. 6 and 7, a plurality of nozzles (openings) 101 are formed at a predetermined pitch along the direction in which the header pipe 100 extends on the side surface of the header pipe 100 facing the steel strip S. ing. Each nozzle 101 is formed by a round hole that penetrates the header tube 100. The diameter of each nozzle 101 is the same as the diameter D of the opening 11b of the nozzle 11 shown in FIGS. Also, the outer diameter and inner diameter of the header pipe 100 are the same as the outer diameter and inner diameter of the header pipe 10 shown in FIGS. The diameter of each nozzle 101 is the same as the diameter D of the opening 11b of the nozzle 11 shown in FIGS. Also, the outer diameter and inner diameter of the header pipe 100 are the same as the outer diameter and inner diameter of the header pipe 10 shown in FIGS.

According to the cooling device according to the first reference example, as shown in FIG. 7, the flow velocity of the air discharged from the nozzle 101 becomes slower from the nozzle 101 toward the steel strip S as the distance from the nozzle 101 increases. flow rate of the central portion is delayed slightly with _{V 6, V 7, V 8} from _{V 5.} From this flow velocity _{V 5} of the reduction to _{V 6, V 7, V 8} way is greater than the manner of deceleration from velocity _{V 1} of the case of the present embodiment to _{V 2, V 3, V 4} , the deceleration of flow velocity The amount is great. For this reason, the sustained distance of the potential core is short, the heat transfer coefficient of the front and back surfaces of the steel strip S to be cooled is low, and the cooling rate of the steel strip S is slow. For this reason, it is difficult to uniformly cool the steel strip S.

  On the other hand, according to the cooling device 1 according to the present embodiment, as described above, the turbulent flow in the nozzle 11 develops because each nozzle 11 includes the refrigerant run-up section forming portion 11a, and the nozzle 11 The straightness of the jet flow ejected from the nozzle 11 is increased, the sustaining distance of the potential core is increased, the heat transfer coefficient of the front and back surfaces of the steel strip S to be cooled is increased, and the refrigerant ejection speed from each nozzle 11 is changed to the steel strip S. The cooling speed of the steel strip S is improved while maintaining the high speed as much as possible until it hits. Thereby, uniform cooling of the steel strip S can be performed.

Next, a cooling device according to a second reference example will be described with reference to FIGS.
As shown in FIGS. 8 and 9, the header pipe 200 of the cooling device according to the second reference example is a cylindrical tubular member having a double-circular cross section, and is elongated in the same direction as the width direction of the traveling steel strip S. Yes. As shown in FIGS. 8 and 9, a plurality of openings 200 a are formed at a predetermined pitch on the side surface of the header pipe 200 facing the steel strip S along the direction in which the header pipe 200 extends. Each opening 202 a is formed by a round hole that penetrates the header tube 200.

  Further, as shown in FIGS. 8 and 9, each nozzle 201 is attached so as to protrude from the header pipe 200 to the round hole constituting each opening 200 a formed in the header pipe 200. Each nozzle 201 is a cylindrical tubular member, and is formed at a refrigerant run-up section forming portion for running the refrigerant from the inside of the header pipe 200 and an outlet of the refrigerant run-up section forming portion, and has run through the inside of the refrigerant run-up section forming portion. And an opening for ejecting air as a refrigerant. The diameter of the opening of the nozzle 201 is the same as the diameter D of the opening 11b of the nozzle 11 shown in FIGS. Further, the protruding length of the nozzle 201 outward from the outer surface of the header pipe 200 is the same as the length L of the nozzle 11 shown in FIGS. Also, the outer diameter and inner diameter of the header pipe 200 are the same as the outer diameter and inner diameter of the header pipe 10 shown in FIGS.

According to the cooling device according to the second reference example, each nozzle 201 is provided with the refrigerant run-up section forming portion, so that the turbulent flow in the nozzle 201 develops and the straightness of the jet ejected from the nozzle 201 increases. In addition, the potential core lasts longer. FIG. 9 shows the discharge flow rate distribution of air (refrigerant), and the flow rate of air discharged from the nozzle 201 becomes slower from the nozzle 201 toward the steel strip S as the distance from the nozzle 201 increases. flow rate of parts are slowed slightly with _{V 10, V 11, V 12} from _{V 9.} However, since each nozzle 201 is provided with the refrigerant run-up section forming portion, the straightness of the jet flow ejected from the nozzle 201 is increased, so that the flow velocity V ₉ and V _{12 at} the central portion of the jet flow are different, The amount of deceleration of the flow velocity is small. Thereby, the heat transfer coefficient of the front and back of the steel strip S to cool increases.

On the other hand, since each nozzle 201 protrudes to the outside from the header pipe 200, the length of the air ejection direction combining the header pipe 200 through which air as a refrigerant flows and the nozzle 201 that ejects air may be shortened. Inability to do so increases the size of the cooling equipment.
On the other hand, according to the cooling device 1 according to the present embodiment, as described above, since each nozzle 11 is built in the header pipe 10, the header pipe 10 through which air as a refrigerant flows and the air is ejected. The cooling equipment can be made compact by shortening the length of the air ejection direction in combination with the nozzle 11 to be performed.

As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change and improvement can be performed.
For example, the nozzle 11 is attached to the opening 10a formed in the header pipe 10 so as to be incorporated in the header pipe 10, and the refrigerant running section forming portion 11a for running the refrigerant from the inside of the header pipe 10; The nozzle 11 has only to be provided with an opening 11b that is formed at the outlet of the refrigerant auxiliary section forming portion 11a and jets out the refrigerant that has run through the refrigerant auxiliary section forming portion 11a to the outside of the header pipe 10. It is not always necessary to be a cylindrical tubular member attached to the round hole forming the.

For example, when the opening 10a is formed with a round hole, the inner diameter of the nozzle 11 gradually increases from the opening 11b toward the inlet of the refrigerant running section forming portion 11a as in the first modification shown in FIG. It may be formed in a tapered cylindrical tube.
Moreover, like the 2nd modification shown in FIG. 11, the opening 10a may be formed by the slit elongated in the direction where the header pipe | tube 10 is extended, In this case, the nozzle 11 is attached to a slit, the header pipe | tube 10 attached to the slit. It may be configured by a pair of flat plates 11c and 11d extending from the upper and lower edges of the slit.

In the embodiment of the present invention, air is used as the refrigerant, but the refrigerant may be H ₂ gas or a mixed gas of H ₂ gas and N ₂ gas or other inert gas. . Even if the refrigerant is H ₂ gas or a mixed gas of H ₂ gas and N ₂ gas or other inert gas, an effect equivalent to that of air can be obtained.
Further, the refrigerant may be water. Even if the refrigerant is water, an effect similar to that of air can be obtained.

DESCRIPTION OF SYMBOLS 1 Cooling device of steel strip (metal strip) 10 Header pipe 10a Opening 11 Nozzle 11a Refrigerant run-up section forming part 11b Opening part 20 Heat exchanger 20a Refrigerant passage 20b Water passage 21 Refrigerant first introduction pipe 22 Blower 23 Refrigerant second Introduction pipe 24 Refrigerant branch pipe 25 Piping 26 Vertical pipe 27 Front side introduction pipe 28 Piping 29 Back side introduction pipe 100 Header pipe 101 Nozzle 200 Header pipe 200a Opening 201 Nozzle S Steel band (metal band)

Claims (7)

A cooling device for a metal strip that includes a header pipe through which a refrigerant flows and a nozzle that is provided in the header pipe and ejects the refrigerant from the header pipe, and that cools the traveling metal strip by the refrigerant jetted from the nozzle. And
The nozzle is attached to an opening formed in the header pipe so as to be built in the header pipe, and forms a refrigerant run-up section forming section for running the refrigerant from the header pipe and the refrigerant run-up section. A metal strip cooling device comprising: an opening that is formed at an outlet of the portion and that jets out the coolant that has run through the inside of the coolant running section forming portion to the outside of the header pipe.   2. The metal band cooling device according to claim 1, wherein the opening is formed of a round hole, and the nozzle is formed of a cylindrical tubular member attached to the round hole.   The opening is formed as a round hole, and the nozzle is formed in a tapered cylindrical tube whose inner diameter gradually increases from the opening toward the inlet of the coolant run-up section forming portion. Item 4. The metal band cooling device according to Item 1.   The opening is formed by a slit extending in a direction in which the header pipe extends, and the nozzle is configured by a pair of flat plates extending from the upper edge and the lower edge of the slit of the header pipe, which are attached to the slit. The metal strip cooling device according to claim 1, wherein the metal strip cooling device is provided.   The metal strip cooling device according to any one of claims 1 to 4, wherein the refrigerant is air. 5. The metal strip according to claim 1, wherein the refrigerant is H ₂ gas or a mixed gas of H ₂ gas and N ₂ gas or other inert gas. 6. Cooling system.   The metal strip cooling device according to any one of claims 1 to 4, wherein the refrigerant is water.

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