JPH0242380Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a slide and
Regarding the gas reservoir structure of gate valves.

Prior Art In continuous casting of molten steel, the flow of molten steel from the tundish to the mold is controlled by a nozzle stopper or a slide gate valve.

However, especially when casting aluminum-killed steel, alumina generated in molten steel adheres to the wall of injection holes such as immersion nozzles, causing a so-called nozzle blockage phenomenon, which reduces work efficiency and hinders productivity. There's a problem.

As a countermeasure against this problem, a method is mainly used to suppress the adhesion of alumina by blowing an inert gas such as argon gas into the nozzle hole of the upper nozzle, plate brick, or immersion nozzle.

On the other hand, it is well known that a method has been developed in which the slide gate valve is closed when replacing the immersion nozzle or when starting casting, and at the same time argon gas is blown into the injection hole of the fixed plate to prevent the solidification of molten steel. .

The present applicant has previously disclosed the following device as an improved version of these mechanisms. In other words, the "slide" described in Japanese Utility Model Application Publication No. 148462/1987 is a method in which a laminated refractory ring with circumferential and longitudinal gas introduction grooves is fitted into the molten steel flow hole of the slide valve plate.・Valve/plate gas blowing structure"
Alternatively, a gas-impermeable insert nozzle (ring), which has a ring-shaped gas reservoir and centripetal ventilation holes, is fitted to the outer periphery of a fixed plate brick, as described in Japanese Utility Model Application Publication No. 60-11158. This includes a ``sliding nozzle device.''

Problems that the invention aims to solve However, because gas is normally introduced from one place due to the structure and cost of the slide gate valve, pressure loss occurs between the gas inlet side and the opposite side. Argon gas cannot be uniformly discharged all around the nozzle hole. In particular, it is preferable for gas blowing during casting to be at a low flow rate from the viewpoint of steel quality; in this case, problems arise such as insufficient supply of argon gas on the opposite side of the gas inlet.

Means for Solving the Problems In order to solve these drawbacks, the inventors of the present invention conducted various studies on the shape of the gas reservoir, and found that it is difficult to inject argon gas, etc. into the injection hole evenly. The present invention was completed by focusing on the point that the vertical cross-sectional area should be gradually increased as the width of the reservoir goes to the opposite side of the gas introduction pipe.The technical structure of the present invention is as follows. This is as specified in the scope of claims for utility model registration above.

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings showing an example suitable for a fixed plate gas blowing structure.

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, in which 1 constitutes a slide gate valve;
For example, with a high alumina plate, 1a
is an upper fixed plate, 1b is a sliding plate, and 1c is a lower fixed plate. 2 is an injection hole with a diameter of about 35 to 60 mm that is slightly offset to one side of the plate 1. When the holes are aligned as shown in Figure 2, the maximum amount of molten steel flows out, and the hydraulic cylinder ( (not shown) to control the flow rate by moving the sliding plate 1b in the direction of the arrow.

3 is an annular gas reservoir provided at the back of the injection hole 2 of the upper fixing plate 1a by a conventional method. Generally, after forming and firing the upper fixing plate 1a with a thickness of 30 to 35 mm, a diamond core is used to form the upper fixing plate 1a. After drilling a hole into which the ring 5 described later is fitted, a U-shaped groove with a height (in the thickness direction of the plate) of 5 mm and a depth (width) of about 3 to 4.5 mm is cut. It is established by common law.

Note that the annular gas reservoir 3 can also be provided to a predetermined size during molding of the upper fixed plate 1a.

In the conventional example, as shown in FIGS. 6 and 7, the width of the gas reservoir 3 was uniform everywhere in the circumferential direction.
As shown in the figure, the width gradually increases from the gas introduction pipe 4 side to the opposite side.
The maximum width is 1.3 to 1.5 times the width (minimum width) of the gas introduction pipe 4 side.

This is because, when tested using an underwater model device (not shown), if the ratio is less than 1.3, the amount of argon gas (not shown) flowing into the injection hole 2 is larger on the gas introduction pipe 4 side, making it uneven. This is because if it is 1.5 times or more, there will be more parts on the opposite side of the gas introduction pipe 4, and the sides will become uneven.

In this embodiment, the vertical cross-sectional shape of the gas reservoir 3 is a vertically long rectangle, but other shapes such as a circle, a semicircle, an ellipse, a triangle, and a trapezoid can also be used.

Alternatively, the ring 5 described later may be similarly cut.

5 is a gas-impermeable ring made of, for example, Al ₂ O ₃ -C, which is fitted into the hole of the upper fixing plate 1a made by the diamond core in a stacked manner in two stages, upper and lower, and is fixed on the top with mortar. By being fixed to the plate 1a, the annular gas reservoir 3 described above is formed.

Reference numeral 6 denotes a joint (slit) between two layers of the rings 5, and the joints 6 are spaced apart from each other by 0.1 to 0.5 mm, and argon gas is blown into the injection hole 3 in a planar manner.

In addition to the above, the ring 5 may be a gas-impermeable ring with 10 to 20 small holes of 0.2 to 1 mm centripetally formed in the upper and lower parts in the circumferential direction, or a porous ring, etc. as required. It can be any other commonly used item.

Further, regarding the relationship between the gas introduction pipe 4 and the wide portion 7 of the gas reservoir 3, as shown in FIG. 2, they are disposed on opposite sides of each other with the injection hole 2 at the center. Therefore, as shown in FIG. 3, in the case where the gas introduction pipe 4 is installed at an oblique position away from the center line of the upper fixed plate 1a, the width can be smoothly extended toward the opposite side of the injection hole 2. It must be wide.

An example of application of the gas reservoir structure to the upper nozzle will be described with reference to FIG. 4. In the porous nozzle shown in FIG. 4, the outer peripheral surface of a porous brick 5 is surrounded by an iron plate case 8, and a circulating gas reservoir 3 is formed between the outer peripheral surface of the porous brick 5 and the iron plate case 8. From the gas reservoir (2 mm) 3 on the gas introduction pipe 4 side, it becomes a smooth wide part (3 mm) 7 as it goes to the opposite side.

An example of application of the gas reservoir structure to a submerged nozzle will be described with reference to FIG. The immersion nozzle forms a circulating gas reservoir 3 between the porous brick 5 and the immersion nozzle body 9. It becomes a smooth wide part 7 as it goes from the gas reservoir 3 on the gas introduction pipe 4 side to the opposite side.

Example: In a certain company's continuous casting tundish, the outer peripheral corners of the mutual (upper and lower) contact surfaces were made in advance so that one side was 2.
3 mm (corresponding side of the gas introduction pipe) to the opposite side, and the outer periphery of these parts is shrunk-fitted and surrounded by a ring-shaped steel plate, and two layers are laminated to form a dense aluminum plate with 0.2 mm spacing between the joints (slits). _{2O3 -} C
A gas reservoir with an isosceles triangular vertical cross section with a width of approximately 1.4 mm on the gas introduction pipe side and a width of approximately 2.1 mm on the opposite side of the gas introduction pipe was created by fitting a quality ring (inner diameter approximately 60 mm). A three-layer slide gate valve consisting of a high-alumina upper fixed plate was used, and aluminum-killed steel was cast.

Argon gas was blown in at a pressure of 0.8 Kg/cm ² and at a flow rate of 10 Nl/min. In gas blowing using the conventional method, the flow rate of molten steel decreased from the 3 and a half times when four continuous castings were planned, and it became necessary to perform so-called flushing, an operation in which a large amount of gas was blown instantaneously.
In the casting according to the present invention, the flow rate of molten steel was stable and four consecutive castings could be completed.

When the used plates and nozzles were collected and examined, there was almost no alumina adhering to the inside of the injection hole, confirming the effectiveness of the present invention.

The above structure of the present invention is a three-layer slide gate.
Although an example in which the present invention is applied to a valve has been described, the same operation and effect can be achieved when applied to a two-layer slide gate valve.

Effects of the invention The structure of the invention is an improvement on the conventional annular gas reservoir, and simply increases the width of the gas reservoir as it goes to the opposite side of the gas introduction pipe. Although it is only a simple method, it has great advantages, such as preventing nozzle clogging in continuous casting or general ingot making, stabilizing operations, and improving productivity.

[Brief explanation of the drawing]

1 to 5 are schematic diagrams showing an embodiment of the present invention, and FIGS. 6 and 7 are schematic diagrams showing a conventional example, in which FIG. 1 is a longitudinal cross-sectional view, and FIG. 2 is a schematic diagram showing a conventional example. Horizontal sectional views, FIGS. 3 and 5 show other embodiments, and in the figures, 1... plate, 3... gas reservoir, 5...
...Ring, 7...Wide part, 8...Iron plate case, 9
...This is the immersion nozzle body.

Claims (1)

[Scope of utility model registration request] In a slide gate valve equipped with a gas blowing mechanism in the injection hole, a horizontal section of a gas reservoir 3 provided around the back of the gas injection refractory installed in the injection hole 2 of at least one type of plate group or nozzle group. The shape is wider toward the opposite side of the gas introduction pipe 4 attachment part, the horizontal cross-sectional maximum width of the gas reservoir 3 is 1.3 to 1.5 times the minimum width, and the vertical cross-sectional shape of the gas reservoir 3 is polygonal. , a gas reservoir structure of a slide gate valve, characterized in that it is circular, oval, semicircular, semi-elliptical, triangular or trapezoidal.