JP2808499B2 - Steel plate water cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel plate immersion type water cooling apparatus disposed at an outlet of a hot rolling mill, a continuous annealing furnace or the like.

[0002]

2. Description of the Related Art Conventionally, for example, in a hot rolling facility, as shown in FIG. 3, a hot steel sheet 015 rolled to a required thickness by a finishing mill 010 is cooled to a predetermined temperature by a cooling device 020. Then, it is wound around a hot rolled coil by a winder 030.

[0003] As shown in FIG. 4, the cooling device 020 is provided with a nozzle 01 having a slit-like slit 02 along the longitudinal direction of the water injection header 04, and the plate-like laminar flowing water 05 ejected from the slit 02 is provided. A slit laminar cooling type in which water is injected into a traveling steel plate 015 is usually employed.

[0004]

According to the above-mentioned conventional cooling method, sufficiently high heat transfer can be achieved at the jet impingement portion, but at other portions, the cooling water and the object to be cooled are provided. And a so-called film boiling state in which a thin vapor film is formed, and the amount of heat transferred is small and cooling is insufficient.

It is conceivable to increase the number of jet nozzles in order to enhance the cooling effect. However, increasing the number of jet nozzles requires an enormous amount of cooling water more than the current level, and is not economically feasible. .

[0006] Further, the current water use efficiency is as small as about 10% even considering only the use of sensible heat.

Therefore, there is a problem that the cooling effect must be enhanced while increasing the utilization efficiency of the cooling water.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a water cooling apparatus for a steel sheet according to the present invention cools a steel sheet by running it in cooling water in a pool in order to cool the lower surface of the steel sheet with an intermittent water flow. In the water cooling device for a steel plate, an upper end is connected to the lower surface of the pool and opened to face the lower surface of the steel plate below the bottom plate of the pool, and an upper curved portion and a lower curved portion are provided below the pool. A nozzle tube and a pulsation source provided at the other end of the nozzle tube via an air chamber are provided.

In order to prevent the cooling water from flowing back into the air chamber,
The water cooling device includes a common gas supply source and a branch pipe that communicates with both the pool bottom and the air chamber to supply gas, and a portion between the branch of the branch pipe and the pool bottom is the nozzle. A U-shaped tube is formed in the same horizontal direction as the tube, and the U-shaped tube has an opening that communicates with the outside air at a position substantially at the same level as the upper curved portion and the lower curved portion of the nozzle tube. Is preferred.

[0010]

In the above-described water cooling apparatus for steel sheets of the present invention,
An appropriate constant flow rate of gas is supplied from a gas supply to the pressure regulating tube. This gas presses against the water surface in the pressure control pipe against the head pressure of the pool, and is released to the outside air from the opening of the U-shaped pipe.

At this time, the air pressure in the pressure control pipe is higher than the outside air pressure by the head difference between the water level in the pressure control pipe pressed down to the position of the discharge opening to the outside air and the pool water level.

As a result, the pressure of the air chamber communicating with the pressure regulating pipe is also pre-pressed by the same amount, and a free surface is formed at an appropriate position in the pulsating cooling nozzle.

Next, the cooling water column in the nozzle pipe is pulsated by periodically pressurizing and depressurizing it by a pulsation source, and the pulsation causes the jet of cooling water jetting from the opening of the nozzle pipe to travel. Intermittent collision with the lower surface of the steel plate.

The jet penetrates the vapor film generated on the lower surface of the steel plate and directly contacts the lower surface of the steel plate to promote cooling of the steel plate.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cutaway side view of a steel sheet water cooling device of the present invention, and FIG. 2 is an enlarged cross-sectional view taken along the line II-II of FIG.

In FIG. 1, a pool 9 formed by a bottom plate 7 and a side wall 8 has a roller 9 rotatably mounted therein and is filled with cooling water 11.

Reference numeral 15 denotes a steel plate to be cooled, which travels in the pool 10 and is cooled by cooling water 11 in the pool 10.

An upper curved portion 1a and a lower curved portion 1b are formed below the bottom plate 7 of the pool 10 so that the upper end thereof penetrates the bottom plate 7 of the pool 10 and faces the lower surface of the steel plate 15 and is located below the pool. At the same time, a nozzle tube 1 whose lower end is attached to the air chamber 4 is provided.

A pulsation source 6 is connected to the air chamber 4 and a plurality of nozzle tubes 1 and the air chamber 4 are arranged in the width direction of the steel plate 15.

The lower surface of the steel plate 15 is cooled by an intermittent water flow by a water pool 10, a nozzle 1, an air chamber (resonance tube) 4 and a pulsation source 6.

The nozzle 1 is bent to form a U-shaped portion,
A free surface of water is formed in the nozzle 1. 13
Indicates a water column in the nozzle 1.

Reference numeral 2 denotes a pressure control pipe, which connects the lower part of the pool 10 and the gas supply source 5 outside the pool 10, and has a branch pipe connected to the air chamber 4. Reference numeral 25 denotes a branch portion of the branch pipe.

The pressure adjusting pipe 2 between the branch portion 25 and the lower part of the pool 10 forms a U-shaped pipe near the same level as the upper curved portion 1a and the lower curved portion 1b of the nozzle tube 1. As shown in FIG. 2, a gas discharge hole 3 communicating with the outside air is provided near the center.

The gas supply source 5 makes the air chamber pressure higher than the outside air by the head difference between the free surface and the free surface in the water pool in order to form a free surface of water in the U-shaped tube portion of the nozzle 1. It serves as a pressurizing device.

In order to automatically control the pressure of the gas supply source 5, which is a pressurizing device, one end of the pressure control tube 2 is connected to the gas supply source 5, the other end is branched, and one end is connected to the air chamber. 4
And the other is connected to the bottom of the water pool 10.

An air chamber 4 is supplied by a gas supply source 5 which is a pressure source.
Then, the inside of the nozzle pipe 1 is pressurized with a pressure corresponding to the head pressure of the cooling water 11, and the cooling water 11 descending from the pool 10 is cooled between the upper curved part 1 a and the lower curved part 1 b of the nozzle pipe 1.
By stopping at an upright portion suitable for the pulsation 1, the cooling water is prevented from entering the air chamber 4, the gas supply source 5, and the pulsation source 6.

At the same time, the pressure regulating pipe 2 is also pressurized by the gas supply source 5 at the same pressure as described above, and the cooling water 11 descending from the pool 10 and passing through the lower curved portion 2b of the pressure regulating pipe 2
The height of the water column 13 in the nozzle tube 1 is set by adjusting the pressure so that the water surface stops at the position of the gas discharge hole 3 and the cooling water flows out.

Next, the hot steel sheet 15 hot-rolled by, for example, a finishing mill (not shown) is run on the rollers 9 in the pool 10. The water column 13 is pulsated by periodically increasing and decreasing pressure by the pulsation source 6, and the pulsation causes the jet 1, which is ejected from the opening of the nozzle tube 1.
2 intermittently collide with the lower surface of the running steel plate 15.

The jet 12 penetrates the vapor film 14 generated on the lower surface of the steel plate 15 and directly contacts the lower surface of the steel plate 15 to promote cooling of the steel plate 15.

The upper surface of the steel plate 15 is also pulsated in the upper nozzle 21 by a pulsation source and an air chamber (not shown) to cause the jet 22 to collide with the steel plate 15 and penetrate the vapor film 24 generated on the upper surface of the steel plate. It comes into direct contact with the upper surface of the steel plate to promote its cooling.

[0031]

As described above, according to the water cooling apparatus for a steel sheet of the present invention, the air chamber is pressurized in accordance with the head pressure of the cooling water from the pool, whereby the pressure of the cooling water below the steel sheet is reduced. The cooling water column can be pulsated in the nozzle tube by preventing intrusion into the source and the pulsation source.

Further, the position of the cooling water column in the nozzle pipe can be easily set by the automatic pressure adjusting action by the gas outflow from the gas discharge hole of the pressure adjusting pipe.

As a result, the cooling water jet from the nozzle pipe opening due to the pulsation of the cooling water column can collide with the lower surface of the steel plate and penetrate the vapor film to make direct contact,
High heat transfer can be obtained without increasing the supply of cooling water,
The cooling rate of the steel sheet can be increased.

[Brief description of the drawings]

FIG. 1 is a cutaway side view of a water cooling device for a steel sheet as one embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view taken along line II-II of FIG.

FIG. 3 is a schematic configuration diagram of a conventional hot rolling facility.

FIG. 4 is an enlarged perspective view of the cooling device in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle pipe 2 Pressure control pipe 3 Gas discharge hole 4 Air chamber 5 Gas supply source 6 Pulsation source 7 Bottom plate 9 Roll 10 Pool 11 Cooling water 12 Jet 13 Water column 14, 24 Steam film 15 Steel plate 21 Upper nozzle

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Jun Sakamoto 4-22, Kannonshinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Works, Mitsubishi Heavy Industries, Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) B21B 45/02 C21D 9/573

Claims (2)

(57) [Claims] 1. A water cooling apparatus for a steel sheet, which cools a steel sheet by running the steel sheet in cooling water in a pool, wherein an opening is formed below a bottom plate of the pool, an upper end thereof is connected to a lower surface of the pool and faces the lower surface of the steel plate. And a nozzle pipe provided with an upper curved portion and a lower curved portion below the pool, and a pulsation source provided through the air chamber at the other end of the nozzle pipe. Cooling system. 2. Communicating with both the pool bottom and the air chamber,
A common gas supply source and a branch pipe for supplying gas,
The portion of the branch tube between the branch and the bottom of the pool forms a U-tube at the same horizontal level as the nozzle tube;
2. The water cooling apparatus for a steel sheet according to claim 1, wherein the U-shaped pipe has an opening communicating with the outside air at a position substantially at the same level as a substantially central portion of an upper curved portion and a lower curved portion of the nozzle tube.