JP3510038B2 - Tubular lance tuyere for steel making - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lance tuyere used for blowing a converter, and more particularly to a distribution of cooling water passages capable of eliminating stagnation of the flow of cooling water between an outer pipe and a middle pipe of a porous lance. Regarding

[0002]

2. Description of the Related Art A lance tuyere for converter blowing is used at a distance of 1.5 to 4.0 meters from the molten steel surface, and high pressure oxygen is ejected from the tuyere toward the molten steel. It receives radiant heat from the molten steel and adheres to the metal, causing a significant heat load. Therefore, the lance tuyere generally has a triple tube structure of an outer tube, a middle tube, and an inner tube. High-pressure oxygen flows through the inner tube, and cooling water flows between the inner tube and the middle tube. Flow toward the inner pipe of the lance, the flow moves between the middle pipe and the outer pipe at the tip of the lance, and cools the inside of the curved surface forming the heat-receiving surface facing the molten steel at the tip of the lance. The cooling water is supposed to come back. Here, when the oxygen holes are porous, there is an oxygen hole between the middle tube and the outer tube in cooling the heat receiving surface,
Due to the stagnation of the flow, it was not possible to cool it sufficiently and many improvement measures have been taken. For example:

(1) A method of narrowing the gap between the inner surface of the tip and the middle tube so that the linear velocity of the cooling water on the heat receiving surface is 18 m / sec or more (Japanese Patent Laid-Open No. 3-229814) (2) Without stagnation Method of forming flow in one direction
(JP-A-8-103405) (3) A method in which cooling water blowout holes are separately provided asymmetrically to generate a swirl at the center of the tuyere (Japanese Patent Laid-Open No. 1-312023).
(4) Method of installing a plurality of cooling water inlets along the tip of the oxygen hole (Japanese Patent Laid-Open No. 61-15911) (5) Cooling water is swirled in opposite directions to prevent flow of water. There is a method of preventing interference (Japanese Patent Laid-Open No. 53-90109).

[0004]

However, JP-A-3-229814 and JP-A-48-10340.
In the invention of Japanese Patent No. 5 does not eliminate the stagnation region on the back surface of the oxygen hole, and in the invention of Japanese Patent Laid-Open No. 61-15911, the stagnation region does not only move to another region, so that sufficient cooling cannot be performed. There is a problem. Japanese Patent Laid-Open No. 1-312
In the inventions of 023 and JP-A-53-90109, there is a problem that the structure is complicated and the manufacturing cost becomes high. Therefore, when the oxygen holes are porous, cooling of the heat-receiving surface can eliminate the stagnation of the flow due to the presence of the oxygen holes between the middle pipe and the outer pipe, and it is not possible to inexpensively realize a cooling water channel for sufficient cooling. It was difficult.

Therefore, according to the present invention, when the oxygen holes are porous,
An object of the present invention is to provide a structure capable of eliminating a stagnation of a flow due to the existence of oxygen holes between a middle pipe and an outer pipe in cooling a heat receiving surface and realizing a cooling water channel for sufficient cooling at a low cost.

[0006]

The gist of the present invention for achieving the above object is as follows. (1) A concentric circle that passes through the center of each oxygen hole with a constant wall thickness of the outer tube and a bulge on the middle tube side in the curved water channel that forms the heat receiving surface where the oxygen hole at the tip of the tuyere opens A radial direction distribution of the distance between the outer tube and the middle tube in the lance vertical direction on the outer side is a distribution that decreases monotonically outward in the radial direction of the concentric circle, and the circumferential distribution of the distance is
A porous lance tuyere for steel making, which has a distribution that monotonically decreases from a cross section connecting an oxygen hole central axis and a lance tuyere central axis to a cross section that divides an angle formed between two adjacent cross sections into two equal parts.

(2) In the curved water channel forming the heat receiving surface where the oxygen holes at the tip of the tuyere open, the outer tube has a constant wall thickness and the middle tube side is provided with a bulge to form the center of each oxygen hole. The radial distribution of the interval between the outer tube and the middle tube in the vertical direction of the lance inside the concentric circle passing through is a distribution that monotonically decreases outward in the radial direction of the concentric circle, and the circumferential distribution of the interval is defined by oxygen holes. A porous lance tuyere for steel making, which has a distribution that monotonically increases from a cross section connecting the central axis and the central axis of the lance tuyere to a cross section that divides an angle formed by two adjacent cross sections into two equal parts.

(3) In the curved surface portion forming the heat receiving surface where the oxygen holes at the tip of the tuyere open, the outer tube has a constant wall thickness,
A distribution in which a bulge is provided on the side of the middle pipe, and the radial distribution of the distance between the outer pipe and the middle pipe in the vertical direction of the lance outside the concentric circle passing through the center of each oxygen hole is monotonically decreased outward in the radial direction of the concentric circle. And, the circumferential distribution of the intervals, from the cross section connecting the oxygen hole central axis and the lance tuyere central axis,
The distribution is such that the angle between two adjacent cross sections is monotonically reduced to a cross section that divides the angle into two equal parts, and the radial distribution of the distance between the outer pipe and the middle pipe in the lance vertical direction inside the concentric circle is defined as The distribution is monotonically decreasing outward in the radial direction, and the circumferential distribution of the intervals is divided into two equal parts from the cross section connecting the oxygen hole central axis and the lance tuyere central axis. Porous lance tuyere for steelmaking, characterized by a distribution that monotonically increases up to the cross section.

(4) Regarding the distance between the outer pipe and the middle pipe in the vertical direction of the lance, which has a distribution in the radial direction and the circumferential direction, the minimum value thereof is 0.01 to 0.
5. The porous lance tuyere for steel making according to any one of (1) to (3), which is No. 5. (5) In the curved water passage that forms the heat receiving surface where the oxygen holes at the tip of the tuyere open, the outer tube and the middle tube have a constant wall thickness, and the outer tube is inside the concentric circle that passes through the center of each oxygen hole. In the cooling water flow path between the middle tubes, one or more protrusions are arranged on the two outer tangent lines of the oxygen hole passing through the central axis of the lance and on the surface of the outer tube partitioned by the oxygen hole on the cooling water side. Porous lance tuyere for steel making characterized by being installed.

(6) The height of the protrusion is 0.01 as a ratio to the maximum value of the distance between the outer tube and the middle tube in the vertical direction of the lance.
It is-0.99, The porous lance tuyere for steelmaking as described in (5). (7) In the curved water channel forming the heat receiving surface where the oxygen holes at the tip of the tuyere open, outside the concentric circle that passes through the center of each oxygen hole, the wall thickness of the outer tube is constant and it rises to the middle tube side. The radial distribution of the distance between the outer tube and the middle tube in the vertical direction of the lance is a distribution that monotonically decreases outward in the radial direction of the concentric circle, and the circumferential distribution of the distance is defined as the oxygen hole central axis. And a lance tuyere center axis from a cross section connecting the two adjacent cross sections to a cross section that divides the angle formed by two adjacent sections into two equal parts, and inside the concentric circles,
In the cooling water flow path between the outer pipe and the middle pipe, the outer pipe and the middle pipe have the same wall thickness, and the two outer tangent lines of the oxygen hole passing through the central axis of the lance and the outer pipe partitioned by the oxygen hole On the surface of the cooling water,
A porous lance tuyere for steel making, characterized in that one or a plurality of protrusions are provided.

(8) A cooling guide for guiding cooling water to the outside of the lance tuyere and the inside of the lance tuyere of the middle pipe around the oxygen hole along the outer peripheral surface of the oxygen hole to enhance the cooling of the outer peripheral surface of the oxygen hole. The cooling water conduit has an oxygen hole circumferential direction range within the range of 30 ° to 120 ° with the extension line connecting the oxygen hole center and the lance tuyere center being the axis of symmetry on the outside of the lance tuyere. The inside of the lance tuyere is characterized in that it is in the range of 5 ° to 30 ° with the line connecting the center of the oxygen hole and the center of the lance tuyere as the axis of symmetry (1) to (7). Porous lance tuyere for steelmaking.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION
A description will be given with reference to the drawings by taking a porous lance tuyere for steelmaking as an example. FIG. 5 is a vertical sectional view of a steel-made porous lance tuyere having five oxygen holes. FIG. 2 is a curved cross-sectional view of the flow path of the cooling water 9 between the middle pipe 4 and the outer pipe 6 along the heat-receiving surface 8 (oxygen hole opening surface) of the steel-made porous lance tuyere having five oxygen holes. is there. The lance tuyere has a triple tube structure of an outer tube 6, a middle tube 4 and an inner tube 2, and the inside of the inner tube 2 is an oxygen passage 1 through which high-pressure oxygen flows. The supply cooling water 3 flows between the inner pipe 2 and the middle pipe 4 toward the heat receiving surface 8 at the tip of the tuyere, passes through the water receiving port 17 for cooling the heat receiving surface at the tip of the tuyere, and the middle pipe 4 and the outer pipe 6 During this period, the cooling water flow direction 9 moves, the inside of the heat receiving surface 8 facing the molten steel at the tip of the lance is cooled, and the cooling water returns between the middle pipe 4 and the outer pipe 6. Here, in the conventional lance tuyere, when the oxygen holes 7 are porous, the heat receiving surface 8
In the cooling, the oxygen stagnation 7 occurs between the middle pipe 4 and the outer pipe 6, so that the stagnation 10 of the flow is generated outside the oxygen hole 7, and the stagnation 18 of the flow is generated inside the oxygen hole 7 (see FIG. 9) also occurred, and it was not possible to sufficiently cool.

First, the inventions of claims 1, 3, and 4 of the present application for the stagnation 10 of the flow will be described. 3 and 4
FIG. 3 is a view of a part ABCD of FIG. 2 cut out and viewed from above and from the side. In order to eliminate the stagnation 10 of the flow, which is a problem, at the curved surface portion where the oxygen hole 7 at the tip of the tuyere opens, the wall thickness of the outer tube is made constant, and a bulge is provided on the side of the middle tube to form each oxygen hole. The radial distribution of the distance h between the outer pipe 6 and the middle pipe 4 in the vertical direction of the lance outside the concentric circle 14 passing through the center of the lance 7 is set to a distribution that reduces outward in the radial direction of the concentric circle 14, and The distribution in the circumferential direction is reduced from a cross section ox connecting the central axis of the oxygen hole 7 and the lance tuyere central axis o to a cross section oy that bisects the angle formed by two adjacent cross sections ox and ox '. How to decrease the interval h is adjusted by performing linearly as shown in FIG. 3 or curvedly as shown in FIG. The interval is adjusted by keeping the thickness of the outer tube constant and providing a bulge on the middle tube side so as not to adversely affect the heat removal from the heat receiving surface.

The effect of the lance tuyere of the present invention on the stagnation 10 of the flow will be described with reference to FIGS. FIG. 1 is a diagram in which the flow velocity distributions of the conventional tuyere 11 and the tuyere 12 of the present invention are compared and shown together. Cross section D between oxygen holes 7
Since the cross-sectional area of G is small, the flow velocity is large and there is no problem.
On the other hand, the cross-sectional area of the downstream section EF rapidly increases, so that not only the flow velocity of the conventional tuyere sharply decreases,
On the F side, the flow velocity is greatly reduced. On the other hand, in the present invention, since the secondary flow 13 shown in FIG. 6 is generated, there is no unevenness in the flow velocity distribution like the EF of the tuyere 12 of the present invention in FIG. Figure 7
Shows various values of the minimum interval Hmin in FIG.
3 is a comparison of the flow velocity distributions on the EF cross section of FIG. According to this, by satisfying the following formula (1), it is possible to secure a flow velocity of 5 meters per second or more, which is a flow velocity necessary for sufficient cooling. Hmin / Hmax is 0.
If it is less than 01, thermal deformation causes the bulges provided on the outer tube and the middle tube to come into contact with each other, and uniform heat removal cannot be performed.
n / Hmax needs to be 0.01 or more.

0.01 ≦ Hmin / Hmax ≦ 0.5 (1) Next, in the curved surface portion where the oxygen holes at the tip of the tuyere open,
The present invention inside a concentric circle passing through the center of each oxygen hole will be described with reference to the drawings. FIG. 10 shows claims 2 to 4 of the present application with respect to the flow stagnation 18 of FIG.
FIG. FIG. 11 is an explanatory view of another invention (claims 5 and 6) for the stagnation 18 of the flow of FIG.

In order to eliminate the stagnation 18 of the flow, which is a problem, in the inventions of claims 2 to 4, the tuyere tip portion of the tuyere tip is the same as the description of the invention for the stagnation 10 outside the lance hole 7. In the curved surface portion forming the heat receiving surface where the oxygen holes are opened, the outer tube has a constant wall thickness, a bulge is provided on the middle tube side, and the outer tube in the vertical direction of the lance inside the concentric circle passing through the center of each oxygen hole 7. The radial distribution of the distance between the inner tube and the middle tube is a distribution that decreases monotonically outward in the radial direction of the concentric circle, and the circumferential distribution of the distance is determined from the cross section connecting the oxygen hole central axis and the lance tuyere central axis. The distribution is such that the angle formed by two adjacent cross sections is monotonically increased to a cross section that divides the angle into two equal parts. The interval is adjusted by providing a tapered or curved ridge on the middle tube.

The effect of the lance tuyere of the present invention in which the middle pipe is provided with a tapered or curved bulge with respect to the flow stagnation 18 will be described with reference to FIGS. 10 and 14. The tapered ridge 15 is for smoothing the streamline around the oxygen hole 7 and eliminating the stagnation 18 of the flow.
FIG. 14 shows the results of an examination of the specific effect of the relationship between the taper height ratio and the flow stagnation area ratio. That is,
FIG. 14 shows a result of investigating the stagnation area S of the flow with respect to the stagnation area So of the flow in the case where the tapered ridge 15 is not provided by changing the taper height ht in FIG. 10 variously. According to this, the maximum distance H between the outer tube and the middle tube
Formula (2) showing the appropriate range of the maximum value htmax of the taper height ht with respect to max or the maximum distance Hm between the outer pipe and the middle pipe
Indicates an appropriate range of the minimum interval Hmin with respect to ax (3)
By satisfying the formula, the stagnation area S of the flow can be suppressed to 0.2 or less by the value of the ratio to the stagnation area So of the flow when the tapered swell 15 of the present invention is not provided. It becomes possible to cool sufficiently. In addition, htm
ax / Hmax exceeds 0.99 or Hmin / Hmax
If less than 0.01, thermal deformation causes the bulges provided in the outer tube and the middle tube to come into contact with each other, and uniform heat removal cannot be performed, so
htmax / Hmax ≦ 0.99 or Hmin / Hm
It is necessary to set ax ≧ 0.01.

[0018]           0.5 ≦ htmax / Hmax ≦ 0.99 (2)           0.01 ≦ Hmin / Hmax ≦ 0.5 (3)           Hmin / Hmax = 1-htmax / Hmax (4)

Further, in order to eliminate the stagnation 18 of the flow, which is a problem, in the invention of claim 5 or 6, the outer surface is formed in the curved surface portion forming the heat receiving surface where the oxygen holes at the tip of the tuyere open. Two outer tangent lines of the oxygen hole that pass through the central axis of the lance inside the cooling water flow path between the outer tube and the inner tube inside the concentric circle that passes through the center of each oxygen hole One or a plurality of protrusions are provided on the surface of the outer pipe, which is partitioned by the oxygen holes, on the cooling water side.

According to the invention of claim 5 or 6,
This will be described with reference to FIGS. 11 and 15. In this lance tuyere, the projection 16 disturbs the stagnation 18 of the flow, thereby promoting cooling of the heat receiving surface. FIG. 15 is a diagram showing the relationship between the fin height ratio and the cooling effect ratio. As shown in FIG. 15, by using the ratio hf / Hmax, which is the ratio of the fin height hf of the protrusion 16 and the maximum interval Hmax, the formula (3) is satisfied so that the flow cooling capacity K and the present invention can be satisfied. When the projection 16 is not provided, the value of the ratio of the flow to the cooling capacity Ko can be increased to 1 or more, and sufficient cooling can be achieved.

[0021]           0.01 ≦ hfmax / Hmax ≦ 0.99 (5)

Next, the present invention according to claim 8 will be described with reference to the drawings. FIG. 12 is a diagram showing an example of a cooling water channel in which the present inventions of claim 3 and claim 8 are combined. FIG.
FIG. 9 is a diagram showing an example of a cooling water channel in which the present invention of claims 7 and 8 is combined. The present invention relates to the middle pipe 4 around the oxygen hole 7.
Lance Tuyere Outside (19) and Lance Tuyere Inside (20)
In addition, cooling water is introduced along the outer peripheral surface of the oxygen hole 7 (9) to enhance cooling of the outer peripheral surface of the oxygen hole 7.
0 is provided, and the oxygen hole circumferential range of the cooling water inlets 19 and 20 is set so that, on the outside of the lance tuyere (19), an extension line connecting the oxygen hole center and the lance tuyere center is set as a symmetry axis. ° ~ 1
Within the range of 20 °, inside the lance tuyere (20), 5 ° with the line connecting the oxygen hole center and the lance tuyere center as the axis of symmetry
By setting it in the range of up to 30 °, the cooling around the oxygen holes where the stagnation of the flow is likely to occur is strengthened to achieve uniform cooling of the entire heat-receiving surface. Here, the water inlet 19 for cooling the outside of the oxygen hole
If the range of 30 ° to 120 ° with the extension line connecting the center of the oxygen hole and the center of the lance tuyere as the axis of symmetry is within the range of 30 ° to 120 °, the effect of cooling is recognized. On the other hand, if it exceeds 120 °, interference with the cooling water from the heat receiving surface cooling water inlet 17 becomes large and uniform cooling cannot be performed. Further, the range of the oxygen hole circumferential direction of the oxygen hole inside cooling water inlet 20 is set to 5 ° within the range of 5 ° to 30 ° with the line connecting the center of the oxygen hole and the center of the lance tuyere as the axis of symmetry. If it is less than 30 ° C., the cooling effect is not recognized, and if it exceeds 30 °, interference with the cooling water from the heat receiving surface cooling water inlet 17 becomes large and uniform cooling cannot be performed.

The effect of the lance tuyere of claim 8 is that, on the outside of the concentric circle passing through the center of each oxygen hole, the stagnation 10 of the flow is eliminated by the tapered bulge 15 and the concentric circle passing through the center of each oxygen hole is formed. On the inner side, the taper-shaped bulge 15 smoothes the streamlines around the oxygen holes 7 to eliminate the stagnation 18 of the flow, or the projection 16
As a result, the stagnation 18 of the flow is disturbed and cooling of the heat receiving surface is promoted. Furthermore, inside and outside of the concentric circle passing through the center of each oxygen hole, the water flow from the oxygen hole cooling water inlets 19 (outside), 20 (inside) Due to the collision, the periphery of the oxygen hole 7 is strongly cooled. Since the effects of these parts are combined, the cooling of the heat receiving surface of the tuyere is strengthened as a whole.

As described above, when the lance tuyere oxygen holes are porous, cooling of the heat receiving surface eliminates the stagnation of the flow due to the existence of oxygen holes between the middle tube and the outer tube, and provides a cooling water channel for sufficient cooling. It can be provided at low cost.

[0025]

Embodiments of the present invention will be specifically described below with reference to the drawings. Example 1 This example will be described with reference to FIGS. The lance tuyere used had a diameter of 0.6 meters and 5 oxygen holes. The diameter of each oxygen hole is 0.2 meters and the diameter of the concentric circles 14 is 0.3 meters. The cooling water is flowing at a speed of 20 meters per second in the center of FIG. In this case, in the conventional tuyere, a portion where the flow velocity is 5 meters or less per second occurs outside the oxygen hole 7 as shown by the flow stagnation 10 in FIG. Here, when a part of the area ABCD of FIG. 2 is taken out, it becomes as shown in FIG. In order to eliminate the stagnation 10 of the flow generated at the maximum distance Hmax = 4 cm between the middle tube 4 and the outer tube 6, the center of each oxygen hole 7 is set at the curved surface portion where the oxygen hole 7 at the tip of the lance is opened. The outer tube 6 and the middle tube 4 in the vertical direction of the lance outside the concentric circle 14 passing through
The radial distribution of the distance h is set to a distribution that decreases outward in the radial direction, and the circumferential distribution of the distance h is set to the oxygen holes 7
2 adjacent to each other from the cross section ox connecting the central axis of
The angle formed by the two cross sections ox and ox ′ is reduced to a cross section oy that bisects the minimum interval Hmin of 2 cm.

When this lance tuyere is used, in cooling the heat receiving surface, there is no stagnation of the flow due to the existence of oxygen holes between the middle tube and the outer tube and the flow velocity is 5 meters or less per second, and sufficient cooling can be achieved. It was Further, since it can be sufficiently cooled, damage caused by radiant heat from molten steel and significant heat load due to metal adhesion is reduced, and the tuyere replacement cycle is reduced from 100 times to 250 times as in the conventional case as shown in FIG. It is growing.

Example 2 Next, in the curved surface portion where the oxygen holes at the tip of the tuyere open,
The present invention inside the concentric circle passing through the center of each oxygen hole will be described with reference to FIGS. The diameter of tuyere used, the number of holes, the diameter of oxygen holes, the diameter of concentric circles, the flow velocity of cooling water at the center, and the distance between the middle pipe 4 and the outer pipe 6 are the same as those in the first embodiment. At this time, a stagnation 18 of a flow having a flow velocity of 5 m / sec or less is generated in an area So inside the concentric circle passing through the center of each oxygen hole and having an area So of 10 square centimeters.

Therefore, as shown in FIG. 10, a tapered bulge 15 is added to the middle pipe, and the ratio of the taper height ht to the maximum interval Hmax, ht / Hmax, is set to 0.5. Then, the streamline around the oxygen hole 7 becomes smooth,
The stagnation 18 of the flow was eliminated, the stagnation area S of the flow was reduced to 2 square centimeters, and it became possible to sufficiently cool.

Further, instead of adding the above-mentioned tapered bulge 15 to the middle pipe, as shown in FIG. 11, protrusions 16 are added to the inside of the outer pipe one by one at the stagnation part of the flow, and the protrusion height is increased. hf / Hma, which is the ratio of hf and maximum interval Hmax
x was set to 0.1. Then, the stagnation 18 of the flow is disturbed, and the ratio of the cooling ability K of the flow to the cooling ability Ko of the flow when the projection 16 is not attached becomes 2, and it becomes possible to perform sufficient cooling.

Embodiment 3 Next, an embodiment of the present invention according to claim 8 will be described with reference to FIGS. 12 and 13. Tuyere diameter used, number of holes, oxygen hole diameter, concentric diameter, cooling water flow velocity at the center,
The distance between the middle pipe 4 and the outer pipe 6 is set equal to the value in the first embodiment. At this time, the flow stagnation 1 where the flow velocity is 5 m / sec or less inside the concentric circle passing through the center of each oxygen hole
8 is an area So and 10 square centimeters are generated.
A stagnation 10 of the flow also occurs outside the oxygen holes 7.

Therefore, first, in FIGS. 12 and 13, outside the concentric circle passing through the center of each oxygen hole, the tapered bulge PQR, that is, the line segment PR is aligned with the outer surface of the middle tube of the conventional tuyere. , The RQ and PQ directions were bulged on the outside of the middle pipe, the minimum distance Hmin was set to 2 cm, and the PQR was made to be a triangle so as to satisfy the requirements of the present invention. Further, cooling water guide ports 19 and 20 for enhancing cooling of the outer peripheral surface of the oxygen hole, and the second embodiment.
The tapered protrusion 15 or the protrusion 16 that eliminates the stagnation 18 of the flow is combined inside the concentric circle passing through the center of each oxygen hole described in the above.

With this lance tuyere, in the lance tuyere of FIG. 12, inside the concentric circle passing through the center of each oxygen hole, the tapered ridge 15 makes the streamline around the oxygen hole 7 smooth, The stagnation 18 of the flow is eliminated, or, in the lance tuyere of FIG. 13, the projection 16 disturbs the stagnation 18 of the flow to promote cooling of the heat receiving surface. Further, the stagnation 1 of the flow is caused by the tapered ridge 15 outside the concentric circle passing through the center of each oxygen hole.
0 is canceled. Further, inside and outside of the concentric circle passing through the center of each oxygen hole, the periphery of the oxygen hole 7 is strongly cooled by the collision of the water flow from the cooling water inlets 19 and 20 of the oxygen hole. Since the effects of these parts are combined, cooling is strengthened on the heat receiving surface of the tuyere, and the average temperature is from 200 ℃ to 1 ℃.
It dropped to 90 ° C.

[0033]

When the porous lance tuyere for steelmaking of the present invention is used, when the oxygen holes are porous, the flow stagnation caused by the existence of the oxygen holes between the middle tube and the outer tube in cooling the heat receiving surface is prevented. It is possible to provide a cooling water channel which is eliminated and is sufficiently cooled at low cost.

[Brief description of drawings]

FIG. 1 is an explanatory view of a difference in flow velocity distribution between a conventional tuyere and an inventive tuyere in FIG.

FIG. 2 is a curved cross-sectional view of a cooling water passage along an oxygen hole opening surface of a steel-made porous lance tuyere having five oxygen holes.

FIG. 3 is a partial area ABCD of FIG. 2 in the tuyere of the present invention.
It is the figure which cut out and was seen from the top and the side.

FIG. 4 is a partial area ABCD of FIG. 2 in the tuyere of the present invention.
It is the figure which cut out and was seen from the top and the side.

FIG. 5 is a vertical sectional view of a steel-made porous lance tuyere having five oxygen holes.

FIG. 6 is an area AB which is a part of FIG. 2 in the tuyere of the present invention.
It is a figure of the secondary flow in CD.

FIG. 7 is a relationship diagram between a clearance and a flow velocity distribution.

FIG. 8 is a comparison diagram of the effects of the conventional tuyere and the present invention.

FIG. 9 is an explanatory diagram showing the stagnation of the flow in the curved surface cross section of the cooling water passage along the oxygen hole opening surface of the conventional porous lance tuyere for steel making having five oxygen holes.

FIG. 10 is an explanatory view of the tuyere of the present invention with respect to the stagnation of the flow of FIG. 9;

FIG. 11 is an explanatory view of another tuyere of the present invention with respect to the stagnation of the flow of FIG. 9;

FIG. 12 is a diagram showing an example of a cooling water channel in which the present invention is combined.

FIG. 13 is a diagram showing another example of a cooling water channel in which the present invention is combined.

FIG. 14 is a diagram showing a relationship between a taper height ratio and a flow stagnation area ratio.

FIG. 15 is a diagram showing a relationship between a fin height ratio and a cooling effect ratio.

[Explanation of symbols]

1 ... Oxygen passage 2 ... Inner tube 3 ... Supply cooling water 4 ... Middle tube 5 ... Return cooling water 6 ... Outer tube 7 ... Oxygen hole 8 ... Heat receiving surface 9 ... Cooling water flow direction 10… Flow stagnation (outside) 11 ... Conventional tuyere (part) 12-invention tuyere (part) 13 ... Secondary flow 14 ... Concentric circle passing through the center of each oxygen hole 7 15 ... exciting 16 ... Protrusion 17 ... Water inlet for cooling the heat receiving surface (center hole) 18… Flow stagnation (inside) 19 ... Oxygen hole Outside water inlet for cooling (back hole) 20 ... Oxygen hole inside water conduit for cooling (auxiliary hole)

Claims (8)

(57) [Claims] 1. In a curved surface cooling water channel forming a heat receiving surface where an oxygen hole at the tip of a tuyere opens, the outer tube has a constant wall thickness, and a bulge is provided on the middle tube side so that the center of each oxygen hole is The radial distribution of the distance between the outer tube and the middle tube in the lance vertical direction outside the passing concentric circle is a distribution that monotonically decreases outward in the radial direction of the concentric circle, and the circumferential distribution of the distance is the oxygen hole center. A porous lance tuyere for steel making, which has a distribution that monotonically decreases from a cross section that connects the shaft and the central axis of the lance tuyere to a cross section that divides the angle between two adjacent cross sections into two equal parts. 2. In the curved cooling water channel forming the heat receiving surface where the oxygen hole at the tip of the tuyere opens, the wall thickness of the outer tube is made constant, and a bulge is provided on the middle tube side so that the center of each oxygen hole is The radial distribution of the distance between the outer tube and the middle tube in the vertical direction of the lance inside the passing concentric circle is a distribution that monotonically decreases outward in the radial direction of the concentric circle, and the circumferential distribution of the distance is the oxygen hole center. A porous lance tuyere for steel making, which has a distribution that monotonically increases from a cross section connecting the shaft and the central axis of the lance tuyere to a cross section that divides an angle formed by two adjacent cross sections into two equal parts. 3. In the curved water passage forming the heat receiving surface where the oxygen holes at the tip of the tuyere open, the outer pipe has a constant wall thickness, and a bulge is provided on the middle pipe side so that the center of each oxygen hole is The radial distribution of the distance between the outer tube and the middle tube in the lance vertical direction outside the passing concentric circle is a distribution that monotonically decreases outward in the radial direction of the concentric circle, and the circumferential distribution of the distance is the oxygen hole center. The distribution is such that the cross section that connects the shaft and the central axis of the lance tuyere monotonically decreases from the cross section that divides the angle formed by two adjacent cross sections into two equal parts, and the outer tube and the middle tube in the lance vertical direction inside the concentric circles. And the radial distribution of the distance between the concentric circles is monotonically reduced outward, and the circumferential distribution of the distance is adjacent from the cross section connecting the oxygen hole central axis and the lance tuyere central axis. Two
A porous lance tuyere for steel making, characterized in that the distribution is such that the angle formed by the two above-mentioned cross sections is monotonically increased to a cross section that divides the angle into two equal parts. 4. The minimum value of the distance between the outer tube and the middle tube in the vertical direction of the lance, which has a distribution in the radial direction and the circumferential direction, is 0.01 to 0.5 as a ratio to the maximum value. The porous lance tuyere for steel making according to any one of claims 1 to 3, wherein 5. In a curved water passage forming a heat receiving surface where an oxygen hole at the tip of a tuyere opens, the outer tube and the middle tube have a constant wall thickness, and an outer portion inside a concentric circle passing through the center of each oxygen hole. One or a plurality of protrusions is provided in the cooling water flow path between the pipe and the middle pipe, and two outer tangent lines of the oxygen hole passing through the central axis of the lance and the surface of the outer pipe partitioned by the oxygen hole on the cooling water side. A perforated lance tuyere for steel making, characterized in that 6. The ratio of the height of the protrusion to the maximum value of the distance between the outer pipe and the middle pipe in the vertical direction of the lance is 0.01 to.
It is 0.99, The porous lance tuyere for steel making of Claim 5 characterized by the above-mentioned. 7. In a curved water channel forming a heat receiving surface where an oxygen hole at the tip of a tuyere opens, outside the concentric circle passing through the center of each oxygen hole, the outer tube has a constant wall thickness, and the middle tube side Is provided on the lance so that the radial distribution of the interval between the outer tube and the middle tube in the vertical direction of the lance is monotonically decreased outward in the radial direction of the concentric circle, and the circumferential distribution of the interval is defined as an oxygen hole. The distribution is such that the cross section that connects the central axis and the central axis of the lance tuyere monotonically decreases from the cross section that divides the angle formed by two adjacent cross sections into two equal parts, and inside the concentric circles, the meat of the outer tube and the middle tube With a constant thickness, in the cooling water flow path between the outer pipe and the middle pipe, the two outer tangent lines of the oxygen hole passing through the lance central axis and the surface on the cooling water side of the outer pipe partitioned by the oxygen hole, Porous lathe for steel making characterized by disposing one or a plurality of protrusions The tuyere. 8. A cooling water inlet for guiding cooling water along the outer peripheral surface of the oxygen hole to the outside of the lance tuyere and the inside of the lance tuyere of the middle pipe around the oxygen hole to enhance the cooling of the outer peripheral surface of the oxygen hole. And the oxygen hole circumferential direction range of the cooling water guide port is within the range of 30 ° to 120 ° with the extension line connecting the oxygen hole center and the lance tuyere center being the axis of symmetry on the outside of the lance tuyere. The inside of the lance tuyere is in the range of 5 ° to 30 ° about the line connecting the center of the oxygen hole and the center of the lance tuyere as the axis of symmetry. Porous lance tuyere for steelmaking.