JPH04354859A - Cooling roll - Google Patents

Abstract

PURPOSE:To control the cooling function of a roll used in the condition of high temp. so as to be match with the condition. CONSTITUTION:In a cooling roll, a hollow inner cylinder 2 is coaxingly fixed by providing the prescribed gas 12 in the inside part of a hollow outer cylinder 1 and spiral passages 21 to mutually reverse direction directed to both end parts 122 in an axial direction from center part 121 to the axial direction in the gap are formed and double passage tubes 3 having two passages 31, 32 which are mutually independent are fixed on the axial center of both end part of the inner and outer cylinders, respectively, and the one side passage 31 of each double passage tubes is communicated with the center part 121 of spiral passage. Further, the other passage 32 of each double passage tube is communicated with each end part 122 of the spiral passage to form two systems of circulating passages 4, 5 are switching valve groups 6 are provided on this two system circulating passages, and the switching to supplying/discharging flow direction of an coolant is selectively controlled.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guide roll, such as a steel strip, having a cooling function and used under high temperature conditions.

0002

BACKGROUND OF THE INVENTION In continuous hot-dip metal plating equipment for zinc, aluminum, etc., continuous heat treatment such as the Sendzimir method is performed. Thereafter, the steel strip is immersed in a plating bath, pulled up directly above using a sink roll, and the amount of adhesion is controlled by injecting gas or the like from a nozzle. Finally, the conveyance direction is changed using a deflector roll to move it within the facility.

[0003] The steel strip in contact with this deflector roll is
The temperature is about 50 to 400°C. For this reason, there are problems with the occurrence of scratches due to adhesion of plated metal to the roll surface, and
There are problems such as poor flatness caused by a temperature difference between the roll surface and the steel strip when the inside of the roll is water-cooled, and unevenness in the roll surface temperature distribution.

[0004] The former problem can be solved, for example, by
As disclosed in Japanese Patent No. 1863, techniques such as arranging ceramics, carbon, asbestos, etc. to which plated metal does not easily adhere on the roll surface, and cooling the roll surface from within have been used. The latter problem can be solved, for example, by
As disclosed in Publication No. 1-295358, cooling using hot water reduces the temperature difference between the water supply side and the drainage side,
As disclosed in Japanese Utility Model Application Publication No. 55-176358, this problem is solved by making the cooling water path a symmetrical circulation system.

[0005] However, whether cooling water or hot water is used, non-uniformity in roll surface temperature is unavoidable. For example, in the cooling roll 7a shown in FIG. 7A, fluid entering from the supply side 71 passes between the outer cylinder 72 and the inner cylinder 73 and exits to the discharge side 74. The temperature of the roll surface at this time has a temperature gradient from room temperature to about 80° C. from the supply side to the discharge side, as shown in FIG. 7(B).

On the other hand, the cooling roll 8a shown in FIG.
Here, the central part of the inner cylinder 83 and the outer cylinder 82 is defined as the feeding side 81,
Both ends thereof serve as discharge sides 84. The temperature of the roll surface at this time is as shown in FIG.
There is a temperature gradient from room temperature to about 40° C. from the center of the roll to the discharge side 84 (end of the roll). That is, in the roll of FIG. 7, ear waves occur on the discharge side, and in the roll of FIG. 8, ear waves occur at both ends.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to control the cooling function of rolls used under high temperature conditions.

[0008]

[Means for Solving the Problems] The cooling roll of the present invention includes:
The hollow inner cylinder is coaxially fixed with a predetermined gap provided inside the hollow outer cylinder, and spiral passages oriented in opposite directions are formed in the gap from the axial center toward both axial ends, so that the hollow inner cylinder is fixed coaxially with the hollow outer cylinder. Double passage pipes each having two independent passages are fixed on the axis of both ends of the inner and outer cylinders, one passage of each double passage pipe is communicated with the central part of the spiral passage, and each of the two The other passage of the heavy passage pipe is communicated with each end of the spiral passage to form two circulation passages, and a switching valve group is provided in the two circulation passages to select the supply and discharge direction of the cooling medium. The above-mentioned problem is solved by a means characterized by controlling the switching in a specific manner.

[0009]

[Operation] In the conventional cooling roll, the path through which the cooling fluid passes is fixed, and although it is possible to reduce the temperature gradient on the surface of the roll, it is impossible to modify it.

In the cooling roll of the present invention, two systems of cooling medium circulation passages are provided, and the direction of flow of the medium in the two systems is appropriately switched based on the temperature gradient on the roll surface. The temperature gradient obtained by the two systems is an upwardly convex mountain-shaped gradient and a downwardly convex valley-shaped gradient.

[0011]

[Embodiment] An embodiment of the cooling roll of the present invention will be described with reference to FIGS. 1 to 6.

As shown in FIG. 1, the cooling roll of the present invention includes a hollow outer cylinder 1, a hollow inner cylinder 2, a pair of double passage pipes 3,
It consists of two circulation passages 4, 5 and a group of switching valves 6.

[0013] In this cooling roll, a predetermined gap 12 is provided inside a hollow outer cylinder 1, and a hollow inner cylinder 2 is fixed coaxially therewith. As shown in FIG.
Spiral passages 21 are formed in opposite directions toward both ends 122 in the axial direction. two mutually independent passages 31;
A double passage pipe 3 having a diameter of 32 is connected to the inner and outer cylinders 2 and 1, respectively.
Fix both ends on the axis.

One passage 31 of each double passage pipe 3 is connected to the conduit 3
11 and communicates with the center part 121 of the spiral passage 21,
Further, the other passage 32 of each double passage pipe 3 is communicated with each end 122 of the spiral passage 21 through a conduit 321 to form two circulation passages 4 and 5. A switching valve group 6 is provided in the two-system circulation passages 4 and 5 to selectively switch and control the direction of supply and discharge of the cooling medium.

In the present invention, water, oil, air, etc. are used as the cooling medium. The case where water is used will be explained below.

One of the two systems and circulation passages 4 and 5 (4) is made up of switching valves 61 and 62, conduits 42 and 41, passage 32, conduit 321, end portion 122, and spiral passage 21. The other circulation passage 5 is made up of switching valves 63 , 64 , conduit 52 , conduit 51 , passage 31 , conduit 311 , central section 121 and spiral passage 21 .

Next, the temperature distribution on the roll surface when the dual circulation passages 4 and 5 are used will be explained with reference to FIGS. 3 and 4.

Table 1 shows the opening and closing states of the switching valve group 6.

[0019]

Thermometers (not shown) are provided in the conduits 41 and 52 to measure the temperature of each cooling water on the supply and drainage sides, and the opening and closing of the switching valves 61 to 64 are controlled based on Table 1. A timer may be used to control the opening and closing of the switching valve. For example, when the temperature gradient on the roll surface is 70°C, the timer setting time can be set to 10 minutes to reduce the temperature gradient to 20 to 35°C.

Next, the results of applying the cooling roll of the present invention to an actual steel strip plating line will be explained together with a comparative example of a conventional cooling roll.

[0022] The conditions for implementation are as follows.

Steel strip dimensions: thickness 0.8 mm x width 1219 mm Threading speed:
96m/min Plating bath temperature: 459℃ Cooling roll dimensions: Diameter 1500mm x body length 1500mm
Steel strip temperature: Measured using a radiation thermometer (Em=0.53). The results obtained using a conventional cooling roll as a comparative example are shown in FIG.

The temperature gradient between the cooling water supply side and the drainage side is about 70°C, and the temperature gradient of the steel strip is about 40°C.

On the other hand, the results obtained using the cooling roll of the present invention are shown in FIG. Even though the temperature gradient of the cooling water was about 45 to 50°C, the temperature gradient of the steel strip was about 10°C three minutes after switching the cooling water.

By controlling the temperature gradient according to the present invention, it is also possible to control the flatness of the steel strip's medium elongation, ear waves, etc.

[0027]

Effects of the Invention According to the present invention, for example, not only can the shape of the plated steel strip be maintained well, but also scratches that occur on the conveyor rolls and post-processing equipment after the deflator roll directly above the plating bath can be prevented. etc. can be prevented, and quality and yield can be improved.

The present invention is not limited to continuous hot-dip plating equipment, but can also be applied to cooling rolls for other high-temperature steel strips, such as continuous annealing equipment for non-coated steel sheets.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a cooling roll of the present invention.

FIG. 2 is a perspective view of the inner cylinder of FIG. 1;

FIG. 3 is an operation explanatory diagram showing one cooling pattern of the cooling roll.

FIG. 4 is an operation explanatory diagram showing another cooling pattern of the cooling roll.

FIG. 5 is a graph showing the cooling function of a conventional cooling roll as a comparative example.

FIG. 6 is a graph showing an example of the cooling function of the cooling roll of the present invention.

FIG. 7 shows a longitudinal section (A) of an example of a conventional cooling roll and its cooling function (B).

FIG. 8 shows a longitudinal section (A) of another example of a conventional cooling roll and its cooling function (B).

[Explanation of symbols]

1: Hollow outer cylinder 2: Hollow inner cylinder 3: Double passage pipe 4, 5: 2-system circulation passage 6: Switching valve group

Claims (1)

[Claims] 1. A hollow inner cylinder is fixed coaxially with a predetermined gap provided inside a hollow outer cylinder, and spiral passages are provided in the gap in opposite directions from an axial center portion toward both axial ends. A double passage pipe having two mutually independent passages is fixed on the axis of both ends of the inner and outer cylinders, respectively.
One passage of the double passage pipe is communicated with the central part of the spiral passage, and the other passage of each double passage pipe is communicated with each end of the spiral passage to form two circulation passages. A cooling roll characterized in that a switching valve group is provided in the two-system circulation passage to selectively switch and control the direction of supply and discharge of the cooling medium.