JPH0565545A - Device for stabilizing operation of strip cooler - Google Patents

Abstract

PURPOSE:To allow a strip to pass through a strip cooler in a flat condition by eliminating C-shaped warpage in the strip advancing into the strip cooler after passing through a hearth roll. CONSTITUTION:A C-shaped warpage straightening roll 1 is provided between the hearth roll 3a and the strip cooler 4a, and to the strip X advancing into the strip cooler 4a after passing through the hearth roll 3a, by pushing the C-shaped warpage straightening roll 1, the strip X is made to a flat condition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a device for stabilizing the operation of a strip cooler for cooling continuously running strips.

[0002]

2. Description of the Related Art Recently, a strip cooler using a duct that resonates at a low frequency has been developed. FIG. 2 is a cross-sectional view showing an example of such a strip cooler 4, in which 6 is a duct, and 7a and 7b are attached to both ends of the duct 6 to generate a pressure vibration inside the duct 6. A generator, 8 is a water-cooled cooling box attached to the upper and lower surfaces of the central portion of the duct 6 to remove heat from the gas inside the duct 6, and the duct 6 side has a cooling wall 8a.
X is the strip to be cooled, 9 is the strip X
Is an opening provided on the side surface of the central part of the duct 6 for introducing and discharging the inside of the duct 6. The symbols (a) and (c) respectively indicate the end of the duct 6, and the symbol (b) indicates the central portion of the duct 6.

The above strip cooler is designed as follows.

First, a gas such as air is supplied to the pressure generators 7a and 7b, but the flow rate and pressure thereof differ depending on operating conditions and equipment capacity. When the gas (air) is supplied, the pressure generators 7a and 7b generate pressure oscillations of substantially the same sine curve at the same frequency (F) in the range of 16 to 60 Hz. At this time,
The amplitude of pressure oscillation is 20-40 kPa. The pressure vibrations generated by the pressure generators 7a and 7b are 180 ° out of phase with each other, and when the pressure value generated by the pressure generator 7a on the (a) side is the maximum, The pressure value generated by the generator 7b is minimized. Further, the length of the duct 6, that is, the distance (L) between (A) to (B) to (C) is L = V / (2 · F).
However, V is determined so as to satisfy the relation of the speed of sound transmitted through the gas in the duct 1.

During operation of the strip cooler designed as described above, a standing wave of 1/2 wavelength is formed inside the duct 6 and becomes a resonance state. The pressure distribution inside the duct 6 at that time is shown in FIG. 3 (a). Moreover, the flow velocity distribution of the gas is shown in FIG. In these figures, the solid line is the end of the duct (a).
It shows the distribution when the value of pressure is maximum. The broken line shows the distribution when the pressure value at the end (b) of the duct is minimum. As shown in (a) and (b) of the figure, pressure antinodes are present at both ends of the duct 6, and the amplitude of pressure oscillation is the largest, but the gas flow velocity is almost zero. On the other hand, in the central portion of the duct 6, there is a pressure node, and the amplitude of pressure oscillation is the smallest, but the gas flow velocity is the highest. When the amplitude of the pressure vibration generated by the pressure generators 7a and 7b is 30 kPa, theoretically, the maximum value (Vmax) of the gas flow velocity in the central portion of the duct 6 is as high as 70 m / s. Moreover, the gas flow velocity changes in the range of + Vmax to -Vmax at the same frequency as the pressure fluctuation. Therefore, if the strip X is placed in the central portion (b) of the duct 6 where such a standing wave is formed, the strip X will be placed in the pulsating air flow,
Heat transfer coefficient between strip X and gas in duct 6 (h)
Will grow. Similarly, the cooling wall 8a surface of the duct 6 and the duct 6
The heat transfer coefficient (h) with the internal gas also increases. Therefore, the amount of heat removed from the strip X can be increased.

In addition to the above, 1/4 of the pressure vibration is provided in the duct.
Wavelength, 3/4 wavelength, etc., n / 4 wavelength (where n is a positive integer)
The same effect can be obtained when the standing wave is formed and resonated.

[0007]

When the strip X is applied with a hearth roll (not shown) immediately before the strip cooler 4 and is inverted, the strip X bent by the hearth roll is always C-warped. Since (plastic deformation) occurs, if the strip X is introduced into the strip cooler 4 as it is, the strip X may come into contact with the wall surface. Even if the inlet side of the strip cooler 4 is used to temporarily correct the shape of the strip X together with the seal on the inlet side by using a seal roll or the like (the plate is bent back to be flat within the elastic range), it is separated from the seal roll. The original C-warp appears again in the part where it was opened, and the fundamental solution to the above problem has not been reached.

In order to avoid such contact, the duct 6
There is no choice but to increase the size of the opening 9 for guiding the strip X into the inside, so that the gas in the duct 6 easily leaks to the outside through the opening 9 and the pressure generating devices 7a, 7a.
The pressure wave energy given in b leaks to the outside and the internal pressure amplitude cannot be increased, so that the vibration of the gas in the duct 6 is weakened. Further, if such a leak occurs, the direction of vibration of the gas is not perpendicular to the strip X (becomes oblique), so that a stable resonance state cannot be maintained. As a result, even if the same power is applied to the pressure generators 7a and 7b, the generated pressure amplitude value is small, the vibration amplitude of the gas is also small, and the cooling effect is also reduced.

Further, when the strip X and the cooling wall 8a are widely separated from each other for the purpose of avoiding contact with each other, the duct cross-sectional area becomes large and the gas velocity at the time of gas vibration for the same pressure amplitude becomes small. The heat transfer effect does not improve so much.

The present invention was devised in view of the above problems, and suppresses the occurrence of C warpage of a strip reversed by a hearth roll, and when the strip enters the strip cooler, it comes into contact with the wall surface thereof. Is something that does not happen.

[0011]

Therefore, the present invention relates to the construction of an apparatus for stabilizing the operation of a strip cooler, in which a C-curve straightening roll is provided between the hearth roll and the strip cooler, and the strip cooler passes through the hearth roll. The basic feature is that the C-curvature straightening roll is pressed against the strip that enters the inside to correct the C-warp straightening of the strip.

In the second aspect of the invention, in addition to the above C warp straightening roll, a pair of seal rolls are provided on the inlet and outlet sides of the strip cooler to suppress gas leakage on the inlet and outlet sides and to position the strip pass line. I try to prevent the vibration.

[0013]

When the strip is subjected to plastic deformation opposite to that of the C-warp by the above C-warp straightening roll and the strip is flattened and then introduced into the strip cooler, contact between the wall surface and the strip occurs in the cooler. Will be deterred.

[0014]

EXAMPLES Specific examples of the apparatus of the present invention will be described below.

FIG. 1 shows an apparatus configuration according to an embodiment of a strip cooler operation stabilizing apparatus of the present invention, where X in the figure.
Is a strip, 3a and 3b are hearth rolls, 4a to 4c and 4d
4f are strip coolers.

In the present embodiment, a C-warp straightening roll 1 is provided between the hearth roll 3a on the entrance side and the strip cooler 5a. By pressing the C-warp straightening roll 1 against the strip X, A plastic deformation opposite to the C-warp deformation generated in the strip X bent by the hearth roll 3a is applied to the strip X. By giving such plastic deformation, the strip X is flattened and introduced into the strip coolers 4a to 4f.

Further, in this embodiment, since the pass line changes even if only one C warp straightening roll 1 is provided, the positioning roll 2 is installed together and the pass line is made constant by the combination thereof. I try to keep it.

Further, the strip coolers 4a to 4c and
Since the lengths of the strips 4d to 4f in the longitudinal direction of the strip are each about 2 m, a plurality of strips 4d to 4f are generally used by connecting them as shown in the drawings. At this time, seal rolls 5a and 5b and 5c and 5d are provided at the entrances and exits of the strip coolers 4a to 4c and 4d to 4f connected to each other.
Suppressing gas leakage from 4a to 4c and 4d to 4f, positioning the strip pass line, and strip X
Will prevent the vibration.

As a result of the apparatus configuration as described above, the C-warp does not occur in the strip X passing through the hearth roll 3a, and the strip X passes through the strip coolers 4a to 4f in a flat state. Therefore, the strip cooler 4a
It is not necessary to widen the openings of 4 to 4f, and it is not necessary to separate the cooling walls from the strip X significantly, so that the cooling effect can be further enhanced.

[0020]

According to the strip cooler operation stabilizing apparatus of the present invention described in detail above, the strip is reversed by the hearth roll and enters the strip cooler by pressing the C warping straightening roll against the strip. The occurrence of C warpage is suppressed and contact between the strip and the strip cooler wall surface is prevented. Therefore, the operation of the strip cooler can be performed stably, and since the contact does not occur, it is not necessary to separate the strip cooler wall surface from the strip greatly, and it is possible to enhance the cooling effect of the strip cooler. Becomes Further, by providing seal rolls on the inlet and outlet sides of the strip cooler, it is possible to suppress gas leakage on the inlet and outlet sides, position the strip pass line, and prevent vibration thereof.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a sectional view showing an example of the configuration of a strip cooler.

FIG. 3 is a graph showing distribution of pressure and flow velocity in a duct of the strip cooler.

[Explanation of symbols]

 1 C Warp straightening roll 2 Positioning roll 3a, 3b Hearth roll 4, 4a-4f Strip cooler 5a-5d Seal roll 6 Duct 7a, 7b Pressure generator 8 Cooling box 8a Cooling wall 9 Opening

Front Page Continuation (72) Inventor Shuichi Sugiyama 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (2)

[Claims] 1. A C between the hearth roll and the strip cooler.
A warp straightening roll is provided, and this C is applied to the strip that enters the strip cooler through the hearth roll.
A strip cooler operation stabilizing device for pressing a warp straightening roll to straighten the C warp of the strip. 2. C between the hearth roll and the strip cooler
A warp straightening roll is provided, and this C is applied to the strip that enters the strip cooler through the hearth roll.
The warp straightening roll is pressed to straighten the C warp of the strip, and a pair of seal rolls are provided on the inlet and outlet sides of the strip cooler to suppress gas leakage on the inlet and outlet sides and to position the strip pass line. A strip cooler operation stabilization device characterized by anti-vibration.