JP4301674B2 - Hot air outlet pipe for blast furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an outlet pipe of a hot stove provided with a heat-resistant, pressure-resistant, and retractable telescopic pipe in a system for conveying hot air discharged from a blast furnace hot stove.
[0002]
[Prior art]
For example, as shown in FIG. 1, the hot air shutoff valve 5 of the hot blast furnace for the blast furnace is installed in the middle of the hot air outlet pipe 3, and exhibits a shutoff function when the air blowing of the hot air furnace 1 is switched. As shown in FIGS. 5 and 6, the hot air main pipe 4 and the hot air outlet pipe 3 are configured with an outer skin 6 as shown in FIGS. 5 and 6 so that hot air around 1200 degrees Celsius can be conveyed at a high pressure of about 0.4 MPa. Is a multi-layered structure constructed of a heat-insulating castable layer 7, a heat-insulating brick layer 8, and a fire-resistant brick layer 9.
The hot air outlet pipe 3 is a pipe that connects each hot air furnace 1 and the hot air main pipe 4, and is a complex vertical displacement due to the influence of the thermal expansion in the axial direction of the hot air main pipe 4 and the thermal expansion in the height direction of the hot air furnace 1. Receive. Further, when exchanging the hot air shut-off valve 5, it is necessary to widen the space by about 20 mm to ensure a gap, and a structure capable of absorbing axial displacement is also required. For this reason, the structure has a structure in which an expansion / contraction bellows 10 is provided in the iron skin 6 and a contraction allowance is provided in the brick layer with a contractible material 11 interposed therebetween.
[0003]
Japanese Utility Model Laid-Open No. 58-155598 discloses a joint structure of a hot air pipe connecting portion in which several kinds of brick layers are sequentially laminated on the inner side of an iron skin that covers a sprayable castable layer. This consists of a clay brick refractory brick placed in the center of the joint, and the first brick layer assembled on both sides with different thicknesses on the left and right sides, and alumina fireproof bricks in the center of the joint. The second brick layer in which the insulating bricks with equal thickness on both sides are assembled and aligned with the bricks in the staggered position, the third brick layer formed by masonry with clayey refractory bricks, and the joint at the center of the joint A ceramic fiber bulk having a fourth brick layer made of alumina-based refractory bricks having a step in the surface and a gap corresponding to the step and larger than each brick layer, and an intermediate layer formed between the castable and the first brick layer. Layer and ceramic fiber bulk pieces interposed in gaps formed between each brick layer due to staggered stacking or thickness difference, and joining by staggering the main parts The causes are formed in a zigzag, the variation in the radial direction due to thermal expansion is configured to absorb by utilizing a gap formed in each brick layers.
[0004]
[Problems to be solved by the invention]
However, in the structure as described above, the contraction allowance 11 in the brick layer is occupied by the thermal expansion of the brick itself, and the absorption allowance is insufficient for the axial perpendicular displacement. Even if the angular displacement is not achieved, it is not possible to synchronize with this, and as a result, the brick layer is broken, and the expansion / contraction bellows portion 10 is heated red. In particular, since the heat insulating brick 8 has a low compressive strength and tends to be pulverized, there is a problem that it is easily lost due to a gas flow, and a void is easily formed, and red heat of the iron skin 6 and the stretchable bellows portion 10 is easily generated.
[0005]
The portion of the shrinkage allowance 11 in the brick layer needs to have a certain brick length in order to ensure the stability of the brick structure before and after that, and as a result, it is far from the hot air shutoff valve and is hot repaired. It was also a difficult position.
[0006]
Further, in the structure in which the joints of the brick layer are arranged in a staggered manner as in Japanese Utility Model Publication No. 58-155598, and the hot air pipe is prevented from red heat due to cracks from the joints, the joints are arranged in a staggered manner. It arrange | positions so that the joint part in each brick layer may not become straight arrangement | positioning by changing the thickness of a layer. Thus, if it is going to prevent red hot of a hot-air pipe | tube by a joint in each brick layer, arrangement | positioning of a joint will become complicated, and also the brick thickness of each brick layer will be disperse | distributed to each layer, and brick stacking will become very complicated arrangement | positioning.
[0007]
In view of the above, the present invention provides a hot blast furnace for a blast furnace that is provided with an expansion / contraction structure in the vicinity of a hot air shut-off valve of a hot air outlet pipe to stably follow a complex perpendicular transformation due to thermal expansion and can secure a stable displacement absorption margin. An outlet pipe is to be provided.
[0008]
[Means for Solving the Problems]
That is, the gist of the present invention is as follows.
(1) A hot air outlet pipe for conveying hot air discharged from the hot air furnace is connected to the hot air main pipe via a hot air shut-off valve, and the hot air is sent from the hot air main pipe to the blast furnace main body inside the iron shell. A metal annular body having an undulation formed in an axial direction so as to be opposed to each other so that the concavo-convex portions are combined, and the combination portion of the metal annular body is filled with a compressible material, A hot air outlet pipe for a blast furnace, characterized in that a stretchable structure in which a refractory brick is lined on the inside and a stretchable bellows is provided on the outside of the iron shell across the combination portion is connected to the hot air shutoff valve.
(2) The hot air outlet pipe for a blast furnace as described in (1) above, wherein refractory brick is cast inside the metal annular body.
(3) The hot air outlet pipe for a blast furnace according to (1) or (2), wherein a water-cooled pipe for cooling the metallic annular body is embedded in the metallic annular body.
[0009]
In the hot air tube structure according to the present invention, a pair of metal annular bodies that hold the refractory on the inner surface is combined with irregularities, a contractible material is packed between the metal annular bodies, and an expandable bellows is provided on the outer surface side. It is a part of the hot air tube.
The metal base material is generally cast iron or cast steel, and the brick can be firmly held by casting the outer peripheral end of the refractory brick during casting.
[0010]
【Example】
In the following, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 shows a layout in which hot air generated in each hot stove is blown to a blast furnace through a hot air outlet pipe and a hot air main pipe. FIG. 2 is a cross-sectional view showing details of a hot air outlet pipe for blowing hot air generated in a hot stove. FIG. 3 shows the details of part A of FIG. 4 is a cross-sectional view taken along line BB in FIG.
[0011]
In FIG. 1, hot air generated in the hot air furnace 1 is blown to the blast furnace 2 through a hot air main pipe 4 by a hot air outlet pipe 3 connected to the hot air furnace 1. A hot air shutoff valve 5 is disposed between the hot air outlet pipe 3 and the hot air main pipe 4.
[0012]
FIG. 2 is an embodiment of the present invention and shows the internal structure of the hot air outlet pipe 3 connected to the hot air furnace 1, and the hot air furnace 1 and the hot air shutoff valve 5 are adjacent to the hot air shutoff valve 5. The telescopic tube of the present invention is arranged.
[0013]
FIG. 3 is a detail of a portion A in FIG. 2 and shows details of the telescopic tube portion of the present invention.
In FIG. 3, the iron skin 6 is divided into two parts in the circumferential direction, and the divided parts are covered and sealed with the stretchable bellows 10. A heat insulating castable 7 is stretched on the inner surface of the iron skin 6. Metal annular bodies A and B are stretched inside the heat insulating castable 7. In this example, cast iron was used as the metal annular body 12. This metal annular body 12 is divided into two parts (12, 12 ') according to the iron skin 6, and the divided surface is formed in an uneven shape, and the uneven part is fitted through the contractible material 11. Match. Refractory bricks 9 are stretched on the inner surfaces of the metal annular bodies 12 and 12 '.
[0014]
FIG. 4 is a cross-sectional view taken along the line BB of FIG. 3, in which refractory bricks 9 are cast and arranged on the metal annular bodies 12 and 12 ′. Further, a water-cooled tube 13 is embedded in the metal annular bodies 12 and 12 ′ to protect the metal annular bodies 12 and 12 ′ by water cooling.
[0015]
【The invention's effect】
As described above, in the present invention, the refractory is held on the inner surface, the metal annular body that is combined with the unevenness, and the metal annular body is packed with a shrinkable material, and the iron skin on the outer surface side is packed. The following excellent effects can be obtained by adopting a structure in which an expansion / contraction bellows is provided and the structure is a part of the hot-air tube.
(1) It is possible to stably follow a complicated displacement perpendicular to the axis due to thermal expansion of the hot air main pipe and the hot air furnace, which is received by the hot air outlet pipe.
(2) When exchanging the hot air shut-off valve, ensure a certain contractible allowance, avoiding excessive pressure on the nearby bricks and destroying them, or adversely affecting the brick structure of the hot air furnace or hot air main.
(3) Since the outer edge of the refractory brick is cast into a metal annular body and firmly held, a stable refractory layer can be formed, and the rear metal annular body is directly exposed to hot air. In addition, the hot air temperature can be prevented from decreasing.
(4) The metal annular body can be cooled with water to prevent a decrease in strength due to overheating and an increase in the temperature of the iron skin. Since the cooling water for bypassing the hot air valve can be bypassed, it is not necessary to add a pump or a heat exchanger for this purpose.
(5) When the metal annular body is combined with irregularities, it is not limited to the cylindrical shape as shown in FIG.
(6) Since no heat-insulating brick is used, no void is formed on the back of the refractory brick layer, and the red heat of the iron skin and the elastic bellows is not easily generated.
(7) The expansion and contraction bellows can be installed close to the hot air shutoff valve, and maintenance and inspection are easy when the hot air shutoff air valve is removed.
[Brief description of the drawings]
FIG. 1 shows a layout of a hot air tube in an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing details of a hot air outlet pipe for blowing hot air generated in a hot stove.
FIG. 3 is a diagram showing the details of part A in FIG. 2;
4 is a cross-sectional view taken along the line BB in FIG.
FIG. 5 is a partially enlarged longitudinal sectional view showing a conventional structure example.
6 is a cross-sectional view taken along the line AA in FIG.
[Explanation of symbols]
1: Hot-blast furnace 2: Blast furnace 3: Hot-air outlet pipe 4: Hot-air main pipe 5: Hot-air shut-off valve 6: Iron skin 7: Thermal insulation castable 8: Thermal insulation brick 9: Fire brick 10: Expandable bellows 11: Retractable material 12: Metal Annular body A
12 ': Metal annular body B
13: Water-cooled tube

Claims (3)

A hot air outlet pipe that conveys the hot air discharged from the hot air furnace is connected to the hot air main pipe via the hot air shut-off valve, and the hot air is sent from the hot air main pipe to the blast furnace main body, and is lined inside the iron skin. A metal annular body with irregularities formed in the axial direction is placed facing each other so that the concave and convex parts are combined, and a shrinkable material is packed in the combination part of the metal annular bodies, and the inside of the metal annular body is refractory. A hot air outlet pipe for a blast furnace, characterized in that a stretchable structure in which a brick is lined and a stretchable bellows is provided on the outside of the iron shell across the combination portion is connected to the hot air shutoff valve. The blast furnace hot air outlet pipe according to claim 1, wherein a refractory brick is cast inside the metal annular body. The blast furnace hot air outlet pipe according to claim 1 or 2, wherein a water-cooled pipe for cooling the metallic annular body is embedded in the metallic annular body.

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