JPS6261092B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling/heating device for cooling or heating a strip.

When continuously annealing a metal strip, a cooling method is used in which the strip is wound around a cooled roll and heat is removed from the strip at the contact area between the strip and the roll.

Conventionally, an apparatus having the following structure has been used to carry out a method of cooling a strip by winding the strip around a roll.

As shown in FIG.
is cooled by roll 2. On the other hand, on the opposite side of the roll 2 to the strip 1, a chamber 4 is provided for storing cooling gas sent from a blower 5.
On the surface facing the roll 2, a plurality of rows of nozzles 3a for ejecting cooling gas are provided at equal intervals in the axial direction of the roll 2. In this way, heat is removed from one side of the strip 1 by solid contact heat transfer by the roll 2,
Heat is removed from the other side by convection and radiant heat transfer by the cooling gas.

However, since the roll is cooled by contacting the strip in this way, there may be cases where the roll does not come into contact with the strip partially, and this may cause the temperature distribution in the width direction of the strip to become non-uniform. There is a problem in that when the thermal stress due to the non-uniform temperature distribution exceeds a certain value, the strip deforms.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to alleviate such drawbacks and to provide a device for cooling and heating a strip, which cools or heats the strip without deforming the strip. The structure of the present invention that achieves this object includes a cooling or heating roll around which the strip is wound, a plurality of rows in the axial direction of the roll, and a surface of the strip that is in contact with the roll. A strip cooling/heating device consisting of a nozzle that spouts cooling or heating gas toward the opposite surface, the space formed between the side walls of the pair of nozzles is reduced, and the strip The present invention is characterized in that one or more nozzle combinations are provided in which the pair of nozzles are set at an angle such that the gas reflected by the gas is directed toward the space.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

In the above-mentioned device, the cooling gas ejected from the nozzle is provided to remove heat from the strip, but as a result of an experiment, it was found that the cooling gas can be used to press the strip against the cooling roll using the pressure of the cooling gas. It has been found that this has the function of increasing the adhesion between the two and increasing the cooling effect of the cooling roll. The experimental results are shown in FIGS. 2 and 3. In FIG. 2, the horizontal axis shows the strip temperature drop T due to the cooling device, and the vertical axis shows the temperature difference ΔT in the strip width direction. As T increases, ΔT also increases, and compared to the case of "no gas used", the value of ΔT becomes smaller by a when "normal temperature gas is used (there is no cooling effect with gas)", and when "cooling gas is used" ΔT is further reduced by b. In other words, ΔT when "cooling gas is used" compared to "no gas used"
becomes smaller by c. This means that about 1/3 of the decrease in ΔT due to the use of cooling gas is due to the pressure caused by the gas injection, that is, the gas pressure brings the strip into close contact with the cooling roll, and the gap between the strip and the cooling roll in the width direction of the strip. This is thought to be due to the uniformity of the amount of heat transfer. In FIG. 3, the horizontal axis shows the pressure of the cooling gas, and the vertical axis shows the strip displacement caused by the pressure exerted on the strip by the cooling gas jet. As shown in the figure, the strip displacement increases in proportion to the cooling gas pressure,
Even if it is assumed that the strip and the cooling roll are in uneven contact with a gap of about 0.1mm, if the cooling gas pressure is 500mmH ₂ O, the strip can be pressed against the cooling roll up to a thickness of 1.6mm to maintain uniform contact. I know that I can do it.

From the above, if cooling gas is injected onto the strip at high pressure, the temperature difference in the width direction of the strip can be reduced and deformation of the strip can be prevented.

Now, if we look at the nozzle part of the conventional strip cooling device (see Fig. 4), there are multiple rows of nozzles 3a arranged at approximately equal intervals in the upper part of the chamber 4, and side walls 3a' of adjacent nozzles 3a. Since the space formed between the strip 1 and the nozzle 3a is large and the nozzle 3a is approximately perpendicular to the tangent line drawn to the outer peripheral surface of the cooling roll 2 at the position where the cooling gas hits the roll 2, a large static pressure is created between the strip 1 and the nozzle 3a. could not be formed, and the force of pressing the strip 1 against the cooling roll 2 by the pressure of the cooling gas was not sufficient.

In order to increase this static pressure, the following improvements have been made in the present invention. That is, as shown in FIG. 5, a partition plate 7 is installed between the side walls 3' of a pair of adjacent nozzles 3, located in the upper center of the chamber 4. The partition plate 7 is connected to the cooling roll 2 similarly to the nozzle 3.
Since the space 6 formed between the side walls 3' is considerably smaller than that without the partition plate 7, a large static pressure is generated in the space 6. In addition, since the cooling gas jet ports 3'' are linearly provided in the axial direction of the cooling roll 2, the gas is reflected by the strip 1 in order to form a gas curtain on both sides of the space 6 and further increase the static pressure. The pair of nozzles 3 are set at an angle such that the cooling gas directed toward the space 6. In order to direct the cooling gas reflected from the strip 1 toward the space 6, the value of θ in the figure must be less than 90°. However, since the strip 1 runs, it is better to avoid the angle near 90 degrees and keep it within the range of θ = 45 degrees to 60 degrees. In this example, the angle of θ = 60 degrees The nozzles 3 are each tilted toward the space 6 side.

The operation of such a cooling device will be explained. In this device, the effect of cooling the strip 1 by the cooling gas is the same as in the conventional device, but the force with which the strip 1 is pressed against the cooling roll 2 is increased. In other words, even if the pressure of the cooling gas ejected from the nozzle 3 is the same as before, the space 6 is small and the gas curtain caused by the cooling gas ejected from the nozzle 3 traps the cooling gas in the space 6, increasing the static pressure. . Therefore, the force that presses the strip 1 against the cooling roll 2 is increased, and the contact between the strip 1 and the cooling roll 2 becomes uniform, and the temperature distribution in the width direction of the strip 1 is also uniform, which greatly reduces thermal deformation of the strip 1. be able to.

Although this embodiment shows a case in which the space is made smaller by temporarily installing a partition plate, the present invention is not limited to this, and the space may be made smaller from the beginning. In this embodiment, the nozzles are combined in only one pair of adjacent nozzles, but they do not have to be adjacent to each other, and a pair of nozzles may be used. Further, the number is not limited to one set, and two or three or more sets may be used.

Furthermore, this device can be used not only for cooling the strip, but also as a heating device in which a heating medium is passed through the roll and hot gas is ejected from the nozzle.

As described above with reference to the embodiments and drawings, according to the present invention, the space formed between the side walls of a pair of nozzles is reduced, and the nozzle is moved toward the space side so that the cooling or heating gas is trapped in the space. Since the strip is tilted, the static pressure in the space increases, which causes the strip to come into close contact with the cooling or heating roll, thereby making the temperature distribution uniform in the width direction of the strip, thereby preventing thermal deformation of the strip.

[Brief explanation of the drawing]

Figure 1 is a structural diagram of a conventional strip cooling device, Figures 2 and 3 are graphs showing that the pressure of gas injection has the function of making the temperature uniform in the width direction of the strip, and Figure 4 is FIG. 5 is an enlarged view of a nozzle portion of a conventional strip cooling device, and FIG. 5 is an enlarged view of a nozzle portion of a strip cooling device according to the present invention. In the drawing 1 is the strip, 2 is the cooling roll, 3
is the nozzle, 3′ is the side wall, 3″ is the spout, 6 is the space,
7 is a partition plate.

Claims (1)

[Claims] 1. A cooling or heating roll around which the strip is wound, and a plurality of rows provided in the axial direction of the roll, and a cooling or heating roll directed toward the surface of the strip opposite to the surface that is in contact with the roll. In a device for cooling and heating a strip, the space formed between the side walls of a pair of nozzles is made small, and the gas reflected by the strip is directed toward the space. 1. A device for cooling and heating a strip, comprising one or more nozzle combinations in which the pair of nozzles are set at a certain angle.