JP2022072221A - Plug for bottom blowing tuyere and hardware for plug - Google Patents

Abstract

To improve metal capillary density per horizontal cross-sectional area in a multi-hole plug as compared with conventional technologies.SOLUTION: A bottom blowing tuyere plug includes a plurality of capillaries 21, a gas pool in fluid communication with the plurality of capillaries 21, and an introduction pipe capable of supplying gas to the gas pool. A size S of a fillet 21a formed at a junction between the capillary 21 and the gas pool is 5.0 mm or less.SELECTED DRAWING: Figure 4

Description

The present invention relates to a bottom blown tuyere plug and a plug hardware that can be used for the bottom blown tuyere plug.

As a plug for blowing an inert gas into the bottom of a smelting furnace or the like, a multi-hole plug having a structure in which a large number of metal thin tubes are embedded in a refractory is widely used. For example, International Publication No. 2017/060937 (Patent Document 1) discloses a bottom-blown plug characterized in the ratio of the area of the opening group to the area of the upper surface of the plug, the density of the openings, and the like. Further, in Japanese Patent No. 6640461 (Patent Document 2), the reciprocal of the number density of gas blowing pipes in the gas blowing pipe existing region, the gas blowing pipe located on the outer periphery of the gas blowing pipe existing region, and the outer edge of the plug body are described. A multi-hole plug characterized by the average value of the shortest distance of the gas is disclosed.

International Publication No. 2017/060937 Japanese Patent No. 6640461

For multi-hole plugs, the aim is to improve the density of metal capillaries per horizontal cross section. This is because if the density of the metal capillary in the multi-hole plug can be improved, the flow rate of the inert gas blown into the smelting furnace through the multi-hole plug can be increased, which is expected to improve the smelting efficiency. For example, Patent Document 2 discloses a multi-hole plug in which the reciprocal S (mm ² / piece) of the number density is 100 or less. However, if an attempt is made to increase the density of the metal tubes, the welding work between the metal capillaries and the gas pool becomes difficult, and gas leaks may occur due to poor welding. Therefore, the improvement of the metal capillaries density is limited in the conventional multi-hole plug. ..

Therefore, in the multi-hole plug, it is required to realize a technique capable of improving the metal capillary density per horizontal cross section as compared with the conventional technique.

The bottom blown tuyere plug according to the present invention includes a plurality of thin tubes, a gas pool in which the plurality of thin tubes communicate with each other, and an introduction tube capable of supplying gas to the gas pool. The fillet formed at the joint portion between the thin tube and the gas pool is characterized in that the size of the fillet is 5.0 mm or less.

Further, the metal fitting for a plug according to the present invention includes a plurality of thin tubes, a gas pool in which the plurality of thin tubes communicate with each other in fluid, and an introduction tube capable of supplying gas to the gas pool. The size of the fillet formed at the joint portion between the gas pool and the gas pool is 5.0 mm or less.

According to these configurations, in the multi-hole plug, the distance between the thin tubes can be narrowed as compared with the prior art. This makes it possible to increase the density of metal tubes per horizontal cross section of the multi-hole plug.

Hereinafter, preferred embodiments of the present invention will be described. However, the scope of the present invention is not limited by the preferred embodiments described below.

In one aspect of the bottom blown tuyere plug according to the present invention, in the joint portion, the plurality of thin tubes independently communicate with the gas pool, and the two adjacent plugs in the joint portion are described. The shortest distance between the surfaces of the thin tubes is preferably 8.0 mm or less.

According to this configuration, the metal capillary density per horizontal cross section of the multi-hole plug can be further increased.

The bottom blown tuyere plug according to the present invention has, as one aspect, the maximum value Ls (mm) of the separation distance between the centers of the thin tubes, the number N (lines) of the thin tubes, and the inner diameter Lp (mm) of the introduction tube. ) Is preferably selected so that the parameter Q represented by the equation (1) is 100 or more and 3000 or less.

According to this configuration, the tubule density can be particularly increased to the extent that the pressure loss in the tubules is unlikely to increase.

As one aspect of the bottom blowing tuyere plug according to the present invention, the outer diameter of the thin tube is preferably 6.0 mm or less.

According to this configuration, the metal capillary density per horizontal cross section of the multi-hole plug can be further increased.

Further features and advantages of the invention will be further clarified by the following illustration of exemplary and non-limiting embodiments described with reference to the drawings.

It is a vertical sectional view of the plug for the bottom blowing tuyere which concerns on embodiment. It is a top view of the plug for the bottom blowing tuyere which concerns on embodiment. It is a vertical sectional view of the metal fitting for a plug which concerns on embodiment. It is a vertical sectional view (enlarged view of the part indicated by reference numeral IV in FIG. 3) which shows the joint part of the thin tube and the gas pool in the plug metal fitting which concerns on embodiment.

An embodiment of a bottom blowing tuyere plug and a plug metal fitting according to the present invention will be described with reference to the drawings. Hereinafter, an example in which the bottom-blown tuyere plug according to the present invention is applied to the bottom-blown tuyere plug 1 for blowing gas into a smelting furnace will be described. The plug hardware 2 included in the bottom blown tuyere plug 1 is an example of the plug hardware according to the present invention.

[Structure of plug for bottom blowing tuyere]
The bottom blown tuyere plug 1 according to the present embodiment has a structure in which the plug hardware 2 is embedded in the refractory material 3 (FIG. 1). A plurality of thin tubes 21 are opened on the upper surface 11 of the bottom blowing tuyere plug 1 (FIG. 2). The gas introduced from the introduction pipe 23 is distributed to the plurality of thin tubes 21 via the gas pool 22, and is eventually discharged from the openings of the plurality of thin tubes 21 provided on the upper surface 11 of the bottom blowing tuyere plug 1. As described above, the bottom blowing tuyere plug 1 is a plug capable of supplying gas to the upper surface 11 side via a plurality of thin tubes 21. In the following description, when the vertical direction is referred to, it means the vertical direction defined according to the postures shown in FIGS. 1 and 2. That is, the side of the bottom blowing tuyere plug 1 (plug hardware 2) where the thin tube 21 is provided is referred to as the upper side, and the side where the introduction tube 23 is provided is referred to as the lower side.

The bottom blowing tuyere plug 1 generally has the shape of a quadrangular frustum. That is, the horizontal cross section of the bottom blown tuyere plug 1 (direction orthogonal to the magazine surface in FIG. 1) is a quadrangle, and the cross-sectional area thereof gradually decreases from the lower side to the upper side of the bottom blown tuyere plug 1. .. FIG. 2 shows an example in which the upper surface 11 of the bottom blowing tuyere plug 1 has a rectangular shape. However, when the bottom blowing tuyere plug 1 is formed in a substantially pyramidal trapezoidal shape, the shape of the cross section in the horizontal direction may be a quadrangle, and may be a trapezoid, for example, in addition to the rectangle illustrated in FIG. .. Further, it may be a pyramid other than the quadrangular frustum, or it may be a truncated cone. Further, the central portion having the thin tube and the peripheral refractory may be integrally molded, or the central portion having the thin tube may be inserted and removed.

[Structure of hardware for plug]
The plug hardware 2 has a thin tube 21, a gas pool 22, and an introduction tube 23 (FIGS. 1 to 3). Each part of the plug metal fitting 2 is made of metal, and the connection between the thin tube 21 and the gas pool 22 and the connection between the gas pool 22 and the introduction tube 23 are both made by welding. The metal constituting each part of the metal fitting 2 for the plug may be, for example, a stainless steel pipe for piping specified in JIS G3459. Specifically, stainless steel (SUS304, SUS316, SUS316L, SUS310S, etc.) can be preferably used, but the present invention is not limited thereto. The thin tube 21, the gas pool 22, and the introduction tube 23 may all be formed of the same metal material, or may be formed of different metal materials for each member. For example, the introduction pipe 23 may be a carbon steel pipe for pressure piping such as STPG specified in JIS G3454, or may be SS400 or the like.

The gas pool 22 is a hollow member having a disk-shaped shape. The gas pool 22 is defined by an upper plate 22a to which a plurality of thin tubes 21 are welded, a lower plate 22b to which the introduction pipe 23 is welded, and a side plate 22c. The side plate 22c extends from the lower plate 22b to the upper plate 22a, and extends further upward beyond the upper plate 22a.

In the present embodiment, each thin tube 21 is a straight tube having an outer diameter of 2.0 mm and an inner diameter of 1.0 mm. The plurality of thin tubes 21 are welded to the gas pool 22 (upper plate 22a) so as to extend in parallel with each other. Therefore, the arrangement of the thin tubes 21 on the upper plate 22a is the same as the arrangement of the thin tubes 21 on the upper surface 11 of the bottom blowing tuyere plug 1. In this embodiment, as shown in FIG. 2, a plurality of thin tubes 21 are arranged in a regular hexagonal arrangement. The number of thin tubes 21 per side is 10, and the number of thin tubes 21 is 271. The size of the thin tube 21, the shape in which the thin tube 21 is arranged, and the number of the thin tubes 21 are not particularly limited, and are appropriately selected according to the design concept of the bottom blowing tuyere plug 1. However, when the outer diameter of the thin tube 21 is 6.0 mm or less, it is easy to increase the thin tube density.

Here, the structure and dimensions of the joint portion between the thin tube 21 and the upper plate 22a will be described in more detail with reference to FIG. The thin tube 21 is inserted into a through hole 22d provided in the upper plate 22a and then welded to the upper plate 22a on the lower side (inside of the gas pool 22) of the upper plate 22a. A fillet 21a formed at the time of welding exists at the lower end of the thin tube 21, and the fillet size S is 5.0 mm or less. Since it is necessary to provide the fillet 21a when each thin tube 21 is welded to the upper plate 22a, the separation distance D between the surfaces of the adjacent thin tubes 21 is twice or more the size S of the fillet. Therefore, in the present embodiment, the separation distance D can be set to 10 mm or less. As described above, in the present embodiment, by setting the fillet size S to a relatively small value (5.0 mm or less), the thin tubes are made of thin tubes as compared with the hardware used for the conventional bottom blown tuyere plug. We have succeeded in reducing the separation distance, which makes it possible to increase the density of the capillaries compared to the conventional bottom-blown tuyere plug.

The pitch P, which is the separation distance between the centers of the adjacent thin tubes 21, is obtained as a value obtained by adding the outer diameter of the thin tubes 21 to the separation distance D. In the present embodiment, the outer diameter of the thin tube 21 is 2.0 mm, and the separation distance D can be 10 mm or less, so that the pitch P can be 12 mm or less.

Referring to FIG. 2 again, in the regular hexagonal thin tube arrangement of the thin tubes 21 according to the present embodiment, when the distance between the centers of the two arbitrarily selected thin tubes 21 is the maximum, the regular hexagons face each other. This is the case when two thin tubes 21 located at the two vertices are selected, and the distance thereof coincides with the length of the diagonal line E of the regular hexagon. Since 19 thin tubes 21 are arranged at equal intervals on the diagonal line E, the length of the diagonal line E is 18 times the pitch P of the thin tubes 21.

In the present embodiment, one introduction pipe 23 is provided, and the introduction pipe 23 is a straight pipe having a nominal diameter of 32A and a nominal thickness of Sch / 40 specified in JIS G3454.

According to the study by the present inventors, the formula (1) is used between the maximum value Ls (mm) of the separation distance between the thin tubes 21, the number N (lines) of the thin tubes 21, and the inner diameter Lp (mm) of the introduction tube 23. It has been found that the gas flow rate can be particularly increased when the relationship in which the represented parameter Q is 100 or more and 3000 or less is established.

In the present embodiment, the number N (tubes) of the thin tubes 21 is 271, and the inner diameter Lp (mm) of the introduction tube 23 is 35.5 mm. Further, the maximum value Ls (mm) of the separation distance between the thin tubes 21 is 18 times the pitch P of the thin tubes 21 as described above. And the pitch P can be 12 mm or less. Based on the above numerical conditions, the maximum value of the parameter Q is 4800 (when the pitch P: 12 mm and the fillet size S: 5.0 mm). Here, if the pitch P and the fillet size S are reduced, the value of the parameter Q decreases. When the parameter Q is 3000, the pitch P is 9.5 mm and the fillet size S is 3.7 mm. When the parameter Q is 100, the pitch P is 3.0 mm and the fillet size S is 0.50 mm.

As described above with an example, the parameter Q and the pitch P have a relationship in which the value of the parameter Q decreases when the pitch P is reduced. When the parameter Q exceeds 3000, it means that the pitch P is in the large category within the range satisfying the fillet size specification (5 mm or less) in the present invention, so that the parameter Q is compared with the case of 3000 or less. , The effect of increasing the capillary density is limited. On the other hand, when the parameter Q is less than 100, the inner diameter of the introduction tube 23 becomes too small with respect to the thin tube density, and the pressure loss in the thin tube 21 may increase.

[Manufacturing method of hardware for plugs]
The plug hardware 2 having the structure as described above can be manufactured by, for example, the following method. In forming the joint portion between the thin tube 21 and the upper plate 22a, first, an upper plate 22a provided with a plurality of through holes 22d and a thin tube 21 having a required number (271 in this embodiment) or more are prepared. do. At this time, the upper plate 22a is provided with a plurality of through holes 22d in the same number (271 in the present embodiment) and arrangement (regular hexagonal shape in the present embodiment) as the thin tubes 21 to be provided. Next, the thin tube 21 is inserted into each of the plurality of through holes 22d, and the lower surface of the upper plate 22a and the end of the thin tube 21 are aligned so as to be substantially flush with each other. After that, the lower surface of the upper plate 22a and the end of the thin tube 21 are welded by fiber laser welding. Finally, the welding finishing work (deburring, etc.) that is usually performed is performed to complete the joining between the thin tube 21 and the upper plate 22a.

As described above, by adopting fiber laser welding, the size of the fillet formed at the time of welding can be reduced as compared with the case where the conventional welding method is adopted. In the present embodiment, the size S of the fillet 21a can be reduced to 5.0 mm or less by performing welding of the thin tube 21 and the gas pool 22 by fiber laser welding. Examples of the welding method that can be used in this embodiment include, in addition to fiber laser welding, tungsten inert gas arc welding (TIG welding) and yttrium aluminum garnet laser welding (YAG welding).

Subsequently, the joint portion between the lower plate 22b and the introduction pipe 23 is formed by welding. Further, the upper plate 22a, the lower plate 22b, and the side plate 22c are welded and joined to complete the plug hardware 2. In welding the lower plate 22b and the introduction pipe 23, welding the upper plate 22a and the side plate 22c, and welding the lower plate 22b and the side plate 22c, it is less necessary to reduce the fillet size (fillet size). May exceed 5 mm), so a welding method such as TIG welding may be used in addition to the fiber laser welding exemplified above.

[Composition of refractory]
The refractory material 3 is mainly composed of a refractory raw material containing an oxide as a main component. Here, the main component means a substance contained in the fireproof raw material in the largest mass ratio. Further, the refractory material 3 may contain a carbon raw material, a non-oxide additive and the like in addition to the refractory raw material. The combination and content ratio of the raw materials constituting the refractory material 3 are not particularly limited, and are appropriately selected according to the design concept of the bottom blown tuyere plug 1.

As the oxide contained in the refractory raw material in the refractory material 3, for example, alumina, silica, spinel, magnesia, zirconia, zircon, calcium zirconate and the like can be used. The oxide may be one kind of substance or a mixture of two or more kinds of substances. The refractory raw material in the refractory 3 preferably contains at least one of magnesia and spinel as an oxide, and more preferably contains magnesia. The substance used as the oxide contained in the refractory raw material in the refractory material 3 is appropriately selected according to the use of the bottom blown tuyere plug 1.

When the refractory material 3 contains a carbon raw material, examples of the carbon raw material include graphite, carbon black, pitch, and carbon fiber. The carbon raw material may be one kind of substance or a mixture of two or more kinds of substances. The carbon raw material in the refractory 3 preferably contains at least one of graphite and carbon fibers, and more preferably contains graphite. The substance used as the carbon raw material in the refractory material 3 is appropriately selected according to the use of the bottom blown tuyere plug 1. For example, when the bottom blown tuyere plug 1 is used for an application exposed to a particularly large thermal change, it is preferable to include an expanded graphite pulverized product crushed after an expansion treatment as a carbon raw material in the refractory material 3.

When the refractory material 3 contains a carbon raw material, the content of the carbon raw material is preferably 10 to 50% of the refractory raw material. Here, the "outer hook" refers to the mass ratio of the additive (here, the carbon raw material) when the mass of the base material (here, the fire-resistant raw material) is 100%. In the following, "outer hanging" shall represent the outer hanging mass ratio based on the fireproof raw material unless otherwise specified. The content of the carbon raw material is more preferably 15% or more on the outside. Further, the content of the carbon raw material is preferably 35% or less for the outer cover, and more preferably 25% or less for the outer cover.

When the refractory 3 contains a non-oxide additive, examples of the non-oxide additive include silicon carbide, boron carbide, zirconium borate, aluminum, and silicon nitride. The non-oxide additive may be one kind of substance or a mixture of two or more kinds of substances. The non-oxide additive in the refractory 3 preferably contains at least one selected from aluminum, silicon carbide, and boron carbide, and more preferably contains at least one of aluminum and silicon carbide. The substance used as the non-oxide additive in the refractory material 3 is appropriately selected according to the use of the bottom blown tuyere plug 1. For example, when the bottom blown tuyere plug 1 is used for applications exposed to particularly severe oxidizing conditions, it is preferable to include aluminum as a non-oxide additive in the refractory material 3.

When the refractory material 3 contains a non-oxide additive, the content of the non-oxide additive is preferably 0.01% or more in the outer cover, and more preferably 0.1% or more in the outer cover. preferable. The content of the non-oxide additive is preferably 5% or less for the outer coating, and more preferably 2% or less for the outer coating.

[Other embodiments]
Finally, other embodiments of the bottom blown tuyere plug and the plug hardware according to the present invention will be described. The configurations disclosed in each of the following embodiments can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction.

In the above embodiment, a configuration in which the thin tubes 21 are arranged in a regular hexagonal array with 10 tubes per side has been described as an example. However, in the bottom blown tuyere plug and the plug metal fitting according to the present invention, the arrangement of the thin tubes is not particularly limited.

In the above embodiment, a configuration in which each of the thin tubes 21 is independently welded to the gas pool 22 (upper plate 22a) has been described as an example. However, in the bottom blown tuyere plug and the plug metal fitting according to the present invention, one pipe joined to the gas pool may be provided in a manner of branching into a plurality of thin pipes.

In the above embodiment, the configuration in which the separation distance D between the surfaces of the adjacent thin tubes 21 is 10 mm or less has been described as an example. In the bottom blown tuyere plug and the plug metal fitting according to the present invention, the shortest separation distance between the surfaces of adjacent thin tubes is preferably 8.0 mm or less.

本発明に係る底吹き羽口用プラグおよびプラグ用金物において、パラメータＱは、１５０以上であることがより好ましく、１８０以上であることがさらに好ましい。また、パラメータＱは、２５００以下であることがより好ましく、１５００以下であることがさらに好ましい。 Regarding the above embodiment, it has been explained that the gas flow rate can be particularly increased when the relationship in which the parameter Q represented by the equation (1) is 100 or more and 3000 or less is established.

In the bottom blown tuyere plug and the plug metal fitting according to the present invention, the parameter Q is more preferably 150 or more, further preferably 180 or more. Further, the parameter Q is more preferably 2500 or less, and further preferably 1500 or less.

In the above embodiment, the configuration in which the thin tube 21 is a straight tube having an outer diameter of 2.0 mm and an inner diameter of 1.0 mm will be described as an example, and it will be described that the outer diameter of the thin tube 21 is preferably 6.0 mm or less. bottom. In the bottom blown tuyere plug and the plug metal fitting according to the present invention, the outer diameter of the thin tube is more preferably 4.0 mm or less, further preferably 2.0 mm or less.

It should be understood that with respect to other configurations, the embodiments disclosed herein are exemplary in all respects and the scope of the invention is not limited thereto. Those skilled in the art will be able to easily understand that modifications can be made as appropriate without departing from the spirit of the present invention. Therefore, another embodiment modified without departing from the spirit of the present invention is naturally included in the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be used, for example, as a bottom-blowing tuyere plug for blowing gas into a smelting furnace.

1: Bottom blown tuyere plug 11: Top surface 2: Plug hardware 21: Thin tube 21a: Fillet 22: Gas pool 22a: Upper plate 22b: Lower plate 22c: Side plate 22d: Through hole 23: Introductory pipe 3: Refractory S: Fillet size D: Separation distance P: Pitch Lp: Introductory pipe 23 inner diameter Ls: Maximum separation distance of thin tube 21

Claims (5)

A plurality of thin tubes, a gas pool in which the plurality of thin tubes are in fluid communication with each other, and an introduction tube capable of supplying gas to the gas pool are provided.
A bottom blowing tuyere plug having a fillet size of 5.0 mm or less formed at the joint portion between the thin tube and the gas pool. At the joint portion, the plurality of thin tubes are independently fluidly communicated with the gas pool.
The bottom blowing tuyere plug according to claim 1, wherein the shortest distance between the surfaces of the two adjacent thin tubes at the joint portion is 8.0 mm or less. The maximum value Ls (mm) of the separation distance between the centers of the thin tubes, the number N (lines) of the thin tubes, and the inner diameter Lp (mm) of the introduction tube have a parameter Q represented by the equation (1) of 100 or more. The bottom blown tuyere plug according to claim 1 or 2, which is selected so as to be 3000 or less.

The plug for a bottom blowing tuyere according to any one of claims 1 to 3, wherein the outer diameter of the thin tube is 6.0 mm or less. A plurality of thin tubes, a gas pool in which the plurality of thin tubes are in fluid communication with each other, and an introduction tube capable of supplying gas to the gas pool are provided.
A metal fitting for a plug having a fillet size of 5.0 mm or less formed at a joint portion between the thin tube and the gas pool.

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