JPS5930415A - Removing method of cooling water - Google Patents

Abstract

PURPOSE:To control highly accurately the cooling of a material to be cooled, and to obtain surely a high quality product, by discharging a cooling water staying on the upper surface of the material to the outside after sucking it at the inlet and outlet side ends of a water cooling device by negative pressure. CONSTITUTION:A heated material 1 to be cooled is moved in the direction of an arrow mark A by transfer rolls 2 to cool its upper and lower surfaces by a cooling water 50 jetted from jetting nozzles 3, 4 of a water cooling device 10. The cooling water 50 of the upper surface forms a staying cooling water 51 having the depth (h) on the upper surface of the material 1, and a part of it flows in the forward arrow B direction and the backward arrow C direction of the device 10. A sucking device 20 having water storage chambers 24 thereon which are respectively connected to blowers 21 through pipes 22, is provided to suck up the water 51 from respective sucking ports 23, thereby discharging forcibly the water 51 to the outside of a line by pumps 25 through check valves 27 and drain pipes 26 having small openings 28, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing cooling water that remains on the upper surface of a material to be cooled in a water cooling device for hot steel plates or the like in a rolling line or a heat treatment line.

Generally, when a hot steel plate is water-cooled in a rolling line or a heat treatment line, cooling is performed by spraying pressurized water onto the upper and lower surfaces of the material to be cooled from a spray nozzle, laminar flow nozzle, jet nozzle, or the like.

After colliding with the steel plate, the cooling water injected onto the two sides of the steel plate flows over the surface of the steel plate in the width direction or direction of movement of the steel plate, and falls downward from the end face of the steel plate.

This causes the following problems.

(1) On the inlet side of the cooling system, the cooling water that remains or flows on the top surface of the steel plate flows out to the upstream side of the cooling start position, and the steel plate temperature at the cooling start position decreases, making the steel plate temperature uneven before a predetermined position. Cooling (2) Similarly, on the outlet side of the cooling device, the cooling water that remains on the top surface of the steel plate flows downstream from the cooling end position, so the steel plate is cooled more than necessary, and the desired material quality may not be obtained or cooling may be uneven. This causes problems such as deformation of the pot plate after water cooling. When a hot steel plate is rapidly cooled to a temperature close to occlusion, such as during quenching, even if cooling water remains on the top surface of the steel plate after passing through the cooling device, there is little possibility of deformation or material defects. This is a problem.

Conventionally, to solve the problem (1) above, K
, a slit nozzle was used. Figure 1 shows a partial longitudinal section of the cooling device, where 1 is the material to be cooled (steel plate), 2 is the table roll, 3,4H Suff'V-nozzle, 50 is the spray, 51 is the retained cooling water, 30 is the slit. The nozzle 31 is a water film. The slit nozzle 30 forms a continuous water film 31 perpendicular to the steel plate advancing direction at the inlet end of the cooling device, and the water film dams up the cooling water flowing on the two sides of the steel plate.

The water film 31 ejected from the slit nozzle 30 has a high degree of water convergence and is a high-speed water stream, so it has a high cooling capacity, and is suitable as a part of a cooling device when performing strong cooling such as in a quenching device. This is inconvenient when cooling is performed slowly without requiring rapid cooling, or when the temperature of the steel sheet after cooling is higher than room temperature. That is, there is a problem in that the water film 31 causes supercooling, making it impossible to obtain a desired temperature and making it impossible to obtain a desired material quality.

In order to solve the above-mentioned conventional problems, the present invention provides a method for simply and effectively removing cooling water accumulated on the upper surface of a material to be cooled at the exit side end of a water cooling device, thereby reducing uneven cooling. The aim is to produce high quality products without deformation.

In order to prevent the cooling water stagnant on the upper surface of the hot steel plate water cooling device from flowing out from the water cooling start position to the upstream side in the steel plate traveling direction and/or from the water cooling end position to the steel plate traveling direction downstream side, The system is characterized in that the accumulated water on the upper surface of the steel plate is sucked in by negative pressure at one or both positions on the exit side of the water cooling system, and the sucked cooling water is forcibly discharged by a pump.

FIG. 2 is a longitudinal cross-sectional view of a steel sheet water cooling device illustrating means for embodying the method of removing cooling water accumulated on the upper surface of a steel sheet according to the present invention.

The heated material 1 to be cooled is moved by the transfer roller 2 in the direction of arrow A in the figure, and passes through the water cooling device 10 . The steel plate 1 passing through the water cooling device 10 is cooled on its upper and lower surfaces by cooling water 50 jetted from a fountain nozzle 3.4 provided in the water cooling device 10.

A water film 51 that stays on the upper surface of the steel plate 1 after the collision with the steel plate 1 in which 5 o of cooling water is sprayed from the nozzle 3 on the upper surface of the steel plate and has a depth h that depends on the amount of cooling water sprayed from the nozzle 3 and the shape of the steel plate 1. , and a part of it is located in front of the water cooling device 10 (arrow B in the figure, upstream side in the direction of steel sheet movement) and in the rear of the water cooling device 10 (
It flows on the upper surface of the steel plate 1 toward the arrow C1 (downstream side in the steel plate traveling direction) in the figure. In order to prevent this flow, a suction device 20 for removing the cooling water 51 flowing in the longitudinal direction of the steel plate 1 on the upper surface of the steel plate 1 is disposed at the input/output n end of the water cooling device 10, as shown in the figure.

The suction device 20 includes a blower 21 that generates negative pressure, and a water storage chamber 24 that is connected to the suction port of the blower through piping 22 and has an opening 23 that sucks up the accumulated water 51 on the upper surface of the steel plate 1 to be cooled.
Further, inside the water storage chamber 24, there is a drainage pump 25 for forcibly discharging the cooling water drawn from the suction port 23 to the outside of the line by the negative pressure generated by the blower 21. is built-in.

The negative pressure generated by the blower 21 is set to a value that draws water to a depth h or more of the cooling water 51 that remains on the upper surface of the steel plate 1. Normally -1001uIAq ~ -1000
By selecting an appropriate value between ffAq, the accumulated water can be sucked in just the right amount. The distance from the lowest end of the suction port 23 to the surface of the steel plate 1 is preferably 5118 or more, taking into account contact with the steel plate 1 and the like. This distance can also be increased or decreased depending on the suction power of the blower.

Since the suction device 20 suctions the accumulated water on the upper surface of the steel plate 1 by using negative pressure, the suction and water draining are reliably completed without contacting the steel plate 1. Furthermore, unlike slit nozzles, supercooling does not occur.

A drainage pump 25 is provided inside the water storage chamber 24, and a drain pump 25 is provided inside the water storage chamber 24.
The water sucked in by step 1 is forcibly drained out of the line.

When draining water by gravity, there is a risk that the reliability of suction may be lost due to the presence of a seal, and it is difficult to ensure sufficient drainage capacity, but in the present invention, there is no such fear because the water is forced to drain. Furthermore, by forced drainage, both the negative pressure generation capacity of the suction blower and the amount of suction can be extremely reduced.

As the drainage pump 25, simple equipment such as a submersible pump can be used. In addition, a check valve 27 is provided in the middle of the drain pipe 26 of the pump, and a small opening 28 communicating with the atmosphere in the water storage chamber 24 is provided in the middle of the water distribution pipe 26 inside the water storage chamber 24 so that the water level in the water storage chamber 24 is higher than the water level in the water storage chamber 24. By providing the pump 25 at a suitable position, consideration has been given to ensuring smooth drainage of water when the pump 25 is activated.

The present invention can be easily and economically implemented using the simple device, an example of which has been explained above, and a drive source for small ruts.

By the method of the present invention, the cooling water on the top surface of the liquid cooling material can be reliably sucked and removed, making it possible to control the cooling of the material to be cooled with high precision. It has become easier to produce.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of a water cooling device showing a conventional water cooling device for preventing outflow of water accumulated on the upper surface of a steel plate, and FIG. 2 is a sectional view of the water cooling device showing means for implementing the method of the present invention. 1... material to be cooled (steel plate), 2... dimple roll,
3.4...Spray nozzle, 10...Water cooling device, 2
゜... Suction device, 21... Prower 122... Piping, 23... Suction port, 24... Water storage chamber, 25...
Pump, 26... Drain piping, 27... Check valve, 28
... Opening, 3° ... Slit nozzle, 31 ... Water film, 50 ... Spray, 51 ... Remaining cooling water

Claims (1)

[Claims] l To remove the cooling water that remains on the top surface of the hot steel plate,
The upper surface of the material to be cooled, characterized in that the cooling water is sucked by negative and positive at the inlet end and/or the outlet end of the water cooling device, and the sucked cooling water is forcibly discharged to the outside of the line by a pump. cooling water removal method.