JPH0515365Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a cooling device for hot-rolled steel sheets, and particularly to a cooling device disposed above the hot-rolled steel sheets.

(Prior Art) The coiling temperature of a hot-rolled steel sheet has a very large effect on the mechanical properties of the material, so it must be controlled with high precision.

For this reason, the cooling system (hottranspray) is controlled by a computer, but the cooling system does not actually operate until the computer issues a command.
There is a delay time (response time) between turning ON and OFF, and how to shorten this response time greatly affects control accuracy.

By the way, as shown in FIG. 4, the cooling device that has been commonly used in the past is attached so that one end is connected to the top of the header 1 and the other end is suspended from a position adjacent to the side surface of the header 1. It has a structure in which a large number of inverted U-shaped nozzles 2 are arranged in parallel in the axial direction of the header 1, that is, in the width direction of the hot-rolled steel plate, and the height H and droop of the rising portion 3 of these many inverted U-shaped nozzles 2 are The lengths of the shaped portions 4 were all designed to be the same.

(Problem to be solved by the invention) In the conventional cooling device having the above structure, the nozzle 2
Even though the heights H of the rising portions 3 of the nozzles 2 are all designed to be the same, it is unavoidable that the heights H of the nozzles 2 are slightly different during the installation work of the nozzles 2 to the header 1. .

However, if this height H is different, when the fluid valve installed in the middle of the cooling water pipe to the header 1 receives an ON-OFF switching command from the computer, the water flow from the nozzle 2 with a large height H Even if the water flow stops immediately after the command, a situation occurs in which the water flow from the small nozzle 2 of height H does not stop immediately after the command, and it takes a considerably long response time until the water flow from all nozzles 2 stops completely. The disadvantage was that it required

Additionally, if the water in the header 1 runs out when the computer turns it off, the next time it turns on, water will not be ejected from the nozzle 2 until the header 1 has been filled with cooling water, resulting in a longer response time. It was hot.

Note that Japanese Utility Model Publication No. 1983-24328 is disclosed as a method for improving the responsiveness when the former is turned off, but in order to solve the latter responsiveness when turned on, this cooling device always uses water inside the header. However, it has the following disadvantages: That is, the amount of water required to constantly fill the header with water must be the same as the amount of water coming out of all the nozzles, which is a waste of energy and resources. For the above purpose, cooling water always flows out from all nozzles, so it is not possible to change the state from ON to OFF. Therefore,
In order to turn it off, it is necessary to make sure that water does not fill up inside the header, and the
Responsiveness when turned on deteriorates.

The present invention aims to provide a cooling device that can solve both such problems during ON and OFF.

(Means for Solving the Problems) In order to achieve the above object, the present invention has one end connected to the top of the header disposed above the hot rolled steel plate, and the other end connected to the side of the header. In a cooling device configured to have a large number of inverted U-shaped nozzles installed so as to hang down, arranged side by side in the width direction of the hot rolled steel plate, and turned on and off by a switching valve interposed in the middle of the piping, Among the inverted U-shaped nozzles, at least one of the nozzles located outside the hot-rolled steel sheet beyond the side edge of the hot-rolled steel sheet with the maximum width to be cooled is made lower than the rising height of the other nozzles, and other than the lowered nozzle. A nozzle in which the length of the end drooping part is longer than the length of the drooping part of other nozzles, and the rising height of the switching valve is lowered even when switching to the drain port side, and the length of the drooping part is longer. The structure is such that less cooling water than the maximum jetting amount flows to the header side.

(Function) The hot-rolled steel plate cooling device according to the present invention is installed such that one end is connected to the upper part of the header arranged above the hot-rolled steel plate, and the other end is suspended from a position adjacent to the side surface of the header. In the cooling device, a large number of inverted U-shaped nozzles are arranged in parallel in the width direction of the hot rolled steel sheet, and the inverted U-shaped nozzles are turned on and off by a switching valve interposed in the middle of the piping. Among the nozzles, at least one of the nozzles located outside the hot-rolled steel plate beyond the side edge of the hot-rolled steel plate with the largest width to be cooled is made lower than the rising height of the other nozzles, and the other end of the lowered nozzle has a drooping portion. The maximum ejection amount of a nozzle that has a length longer than the length of the drooping part of other nozzles, and the rising height of the switching valve is lowered even when switching to the drain port side, and the length of the drooping part is longer. It is configured so that less cooling water flows to the header side, and when the nozzle is OFF, the nozzle with a long hanging part acts as a siphon for other nozzles and blows water from other nozzles.
The jetting of water from the other nozzles immediately stops, and the jetting of water from this long hanging nozzle does not hit the hot-rolled steel plate, improving the responsiveness of the entire cooling device. Also, when ON,
When OFF, a smaller amount of water is constantly flowing than the maximum amount of water from the nozzles with low rising heights, so when OFF, water flows only from the nozzles with low rising heights, and water does not flow from other nozzles. Water does not eject and the header is always filled with water, so when you turn it on, water instantly ejects from each nozzle, improving responsiveness when you turn it on.

(Example) The present invention will be described below based on an example shown in FIGS. 1 and 2. In addition, in Figures 1 and 2,
The same numbers and symbols as in FIG. 4 indicate the same or corresponding parts, and detailed explanations will be omitted.

As shown in FIG. 1, the cooling device according to the present invention includes inverted U-shaped nozzles located at both ends of a header 1 located outside the hot-rolled steel sheet beyond the side edge of the widest hot-rolled steel sheet to be cooled, for example. The height H' of the rising part 3 of the nozzle 2' is made lower than the height H of the rising part 3 of the nozzle 2' located in the middle, and the length of the hanging part 4 of the nozzle 2' located at both ends is It is made longer by h than the length of the hanging portion 4 of the nozzle 2 located in the middle.

A spray system diagram of a cooling device equipped with a header having such a configuration is shown in FIG.

In the spray system shown in Fig. 2, the cooling water passes through the ON-OFF valve 5 and the fluid valve 6 to the header 1.
flows until The fluid valve 6 switches the cooling water to the header 1 side or the drain port side.

When cooling the hot-rolled steel sheet, the fluid valve 6 is switched to the header 1 side to allow cooling water to flow into the header 1. However, even if the fluid valve 6 is switched, the piping from the fluid valve 6 to the header 1 ( (including the header) is not filled with water, the header 1 will not be filled until the amount of water corresponding to this piping volume flows through the fluid valve.
Water is not jetted out onto the hot rolled steel sheet, slowing down the actual response time.

However, in the case of the cooling device of the present invention, even when the cooling device is OFF, that is, even when water is flowing from the fluid valve 6 to the drain port side, the amount of jetting from the nozzles 2' located at both ends is always lower than the maximum amount. Since the fluid valve 6 is configured so that a small amount of water also flows to the header 1, the water flowing to the header 1 is not spouted from the nozzle 2 located in the middle, and is Water flows only from the nozzles 2' located at both ends, so that the header 1 is always filled with water.

Therefore, when the cooling system is turned on, that is, when the fluid valve 6 is switched so that water flows into the header 1, water is instantly jetted out from each nozzle 2, 2' of the header 1, and when the cooling system is turned on, improves responsiveness.

On the other hand, the fluid valve 6 is switched from the state in which water is being spouted from each nozzle 2, 2' of the header 1 to the hot-rolled steel sheet to stop the jetting of water to the hot-rolled steel sheet, so that the water flows to the drain port side. In the case of A siphon phenomenon occurs in which the pressure at the opening leading to the nozzle 2' becomes smaller by an amount equivalent to the water column h than the pressure at the opening leading to the nozzle 2 located in the middle, and cooling water is sucked into the nozzle 2' located at both ends. Therefore, due to this siphon phenomenon, water flows out only from the nozzles 2' at both ends, and by preventing the water flowing out from the nozzles 2' at both ends from hitting the hot rolled steel plate, the cooling device Improves responsiveness when turned off.

Although this embodiment uses the fluid valve 6, a mechanical switching valve may be used as long as it allows a small amount of water to flow to the header side when turned off.

Figure 3 shows the case where the cooling device of the present invention is used.
This figure shows a comparison of responsiveness when using a conventional device.

In the conventional device, the time from when the fluid valve 6 is switched until the water actually turns on and off from the header 1 is
It can be seen that the response time, which used to be 4 seconds when ON and 5 seconds when OFF, has been significantly improved with this device to 1 second when ON and 2 seconds when OFF.
The conditions for this experiment are that the difference ΔH between the heights H and H' of the rising parts 3 of both nozzles 2 and 2' is 50 mm, and the hanging part 4 is 50 mm.
The difference in length h is 150 mm, the diameter of nozzles 2 and 2' is φ22 mm, the total number of nozzles 2 and 2' is 48 (32) per header (32 in the case of a narrow header), The diameter was 168 mm, the cooling flow rate was 1300/min per header, and the flow rate when OFF was 10/min per header.

(Effect of the invention) As explained above, in the hot-rolled steel sheet cooling device according to the invention, one end is connected to the top of the header disposed above the hot-rolled steel sheet, and the other end is connected to the side surface of the header. A large number of inverted U-shaped nozzles are installed in parallel in the width direction of the hot-rolled steel plate, and are turned on and off by a switching valve interposed in the middle of the piping.
In a cooling device configured to turn off, at least one of the inverted U-shaped nozzles located outside the hot-rolled steel plate beyond the side edge of the hot-rolled steel plate with the maximum width to be cooled is set at a height higher than that of the other nozzles. In addition, the length of the hanging portion of the other end of the lowered nozzle is made longer than the hanging portion of the other nozzles, and the rising height is maintained even when the switching valve is switched to the drain port side. It is designed so that less cooling water flows to the header side than the maximum jetting amount of the nozzle, which has a lower nozzle and a longer hanging part.
When OFF, the nozzle with a long hanging part acts as a siphon for other nozzles and blows water from other nozzles, and when ON,
When OFF, the amount of water that is smaller than the maximum flow rate from the nozzle with a low rising part height is always flowing, so when OFF, water flows only from the nozzle with a low rising part height, and water is spouted from other nozzles. Since the header is always filled with water, the responsiveness of the cooling system both when turned on and off is improved, and all the drawbacks of conventional cooling systems can be solved.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the present invention, A is a front view, B is a side view, Fig. 2 is a spray system diagram, Fig. 3 is a response time comparison diagram, and Fig. 4 A and B are the conventional case. 1st
This is the same drawing as Figures A and B. 1 is a header, 2 and 2' are nozzles, 3 is a rising part, and 4 is a hanging part.

Claims (1)

[Scope of utility model registration request] An inverted U-shaped nozzle, one end of which is connected to the top of a header disposed above the hot-rolled steel plate, and the other end of which is attached so as to hang down adjacent to the side surface of the header, is connected to the width of the hot-rolled steel plate. In a cooling device configured to be arranged in parallel in a number of directions and turned on and off by a switching valve inserted in the middle of the piping, the side edge of the hot rolled steel plate with the largest width to be cooled among the inverted U-shaped nozzles is At least one of the nozzles located outside the hot-rolled steel plate is made lower than the rising height of the other nozzles, and the length of the other end of the lowered nozzle is made longer than the length of the other nozzles, and , the switching valve is configured such that even when switching to the drain port side, the rising height is lowered and less cooling water than the maximum jetting amount of the nozzle with a longer hanging portion flows to the header side. A cooling device for hot-rolled steel sheets featuring: