JPS6124328Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a cooling device for hot-rolled steel sheets, and more specifically, a number of cooling injection nozzles arranged at predetermined intervals are installed at a predetermined height above the steel sheet and extend in the sheet width direction. This invention relates to a cooling device equipped with a header and injecting water into a running steel plate.

Cooling system for hot-rolled steel sheets consisting of a cooling water header having one leg connected to the top of the header, the other leg hanging down adjacent to the side of the header, and an inverted U-shaped nozzle with a nozzle opening at the bottom end. teeth,
There are problems with responsiveness to cooling water control, such as poor water draining when water injection is stopped and it takes 5-15 seconds for water to drain from all nozzles. In order to improve the response of an inverted U-shaped nozzle, measures such as connecting an air pipe to the curved part of the inverted U-shaped tube or providing an opening in this part are taken, but this does not make the laminar flow inside the nozzle unstable. The current situation is that other problems occur, such as when using the method, and good results cannot be obtained. The present invention aims to solve this type of problem occurring in cooling water injection devices with inverted U-shaped nozzles.

An object of the present invention is to improve the responsiveness of a cooling water injection device having an inverted U-shaped nozzle when injection is stopped.

According to the present invention, a header is installed in the sheet width direction at a predetermined height above a hot rolled steel sheet, one leg is connected to the top of the header, and the other leg is positioned adjacent to the side surface of the header. In a hot-rolled steel sheet cooling device consisting of a number of inverted U-shaped nozzles with nozzles hanging down from the bottom and opening nozzles at the lower ends, at least one nozzle located outside the steel sheet beyond the side edge of the widest steel sheet to be cooled. There is obtained a cooling device for a hot-rolled steel sheet, characterized in that each nozzle has a nozzle hole located below the nozzle holes of other nozzles.

Now, an embodiment of the apparatus of the present invention will be described below with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, there is shown a conventional cooling system 20 comprising a cooling water header 1 having two rows of inverted U-shaped nozzles 2 arranged at a predetermined distance d in its upper part. As shown in FIG. 2, the nozzle 2A on the right side has one leg connected to the opening 3A of the header 1, hangs down adjacent to the right side surface of the other header 1, and has a nozzle hole 6A at its lower end. The left nozzle 2B is attached to the header 1 symmetrically to the nozzle 2A with respect to a vertical center plane YY passing through the center of the header 1. Due to manufacturing errors in each nozzle and other reasons, all nozzles do not stop jetting cooling water at the same time when water injection is stopped, resulting in some nozzles stopping jetting early and other nozzles continuing jetting. In FIG. 2, when the nozzle 2A stops ejecting early and the water level inside the nozzle 2A reaches the curved part 2U of the inverted U-shaped tube, another nozzle 2B
If the cooling water continues to be spouted, the water head h is added to the nozzle hole 6B of the nozzle 2B, so it is thought that the jetting of cooling water from the nozzle 2B will continue for quite a long time. This poor drainage of the cooling device 20 as a whole indicates poor responsiveness to the control operation of stopping cooling, making it difficult to accurately control the cooling rate of the hot rolled steel sheet.

FIG. 3 shows previous measures taken to solve the problem of poor drainage occurring in the cooling device 0 of FIG. 1. In case of a, inverted U-shaped nozzle 2
An air injection pipe 4 is connected to the upper curved portion of A and 2B, and in the case of b, an opening 5 is provided in the curved portion. In either case, some effect is recognized in terms of improving water drainage, but there is a drawback that a steady flow cannot be obtained in the nozzle when cooling water is jetted, making the operation unstable.

4 and 5 show the cooling device 10 of the present invention, in which the header 1 is placed under the maximum width S of the steel plate, the conventional inverted U-shaped nozzles 2A, 2
B is attached, but an irregularly shaped nozzle 7 is provided at a position beyond the maximum width S of the steel plate and outside the steel plate. The irregularly shaped nozzle 7 has one leg 9A constituting a U-shape connected to the header 1, and the other leg 9B extending beyond the side of the header 1 and hanging below the bottom of the header 1. The nozzle 2 is opened downward by a height H from the nozzle hole 6. Because the irregularly shaped nozzle 7 is attached to the header 1, the pressure at the opening 3A of the header 1 communicating with the leg 9A of the irregularly shaped nozzle 7 is smaller than the pressure at the opening 3B communicating with the normal nozzle 2 by an amount corresponding to the water column H.
The cooling water inside is sucked into the irregularly shaped nozzle 7. In other words, the irregularly shaped nozzle 7 acts as a siphon for the entire header 1 including all the regular nozzles 2, and actively discharges the cooling water in the header 1 outside the area of the steel plate at the same time as the cooling device 10 stops jetting out the cooling water. Prevents cooling water from spewing out from normal nozzles.

As shown above, according to the present invention, the response to the control of the cooling system is significantly improved by simply increasing the length of the leg with the injection hole of the nozzle located outside the steel plate, which is an extremely simple and inexpensive procedure. can do.

[Brief description of the drawings]

FIG. 1 is a front view showing a conventional cooling device, FIG. 2 is an end view of the device in FIG. 1, FIG. 3 is an end view showing a modification of the device in FIG. 5 is an end view of the apparatus of FIG. 4; FIG. 1... Header, 2A, 2B... Inverted U-shaped nozzle, 3A, 3B... Opening, 4... Air injection pipe, 5
...Air supply hole, 6A, 6B... Nozzle hole, 7... Irregular nozzle, 8... Nozzle hole, 9A, 9B... Legs of oddly shaped nozzle.

Claims (1)

[Scope of utility model registration request] A header installed at the top of a hot-rolled steel plate, and a number of inverted U's with one leg connected to the top of the header, the other leg hanging down adjacent to the side of the header, and a nozzle hole opened at the bottom end. In a hot-rolled steel sheet cooling device consisting of a shape nozzle, at least one nozzle located outside the steel sheet beyond the side edge of the widest steel sheet to be cooled is located below the nozzle holes of the other nozzles. A cooling device for hot-rolled steel sheets, characterized by being equipped with injection holes.