JP2023146372A - Expansion joint - Google Patents

Abstract

To provide an expansion joint capable of avoiding piping system obstruction or clogging of a tuyere of a blast furnace, which are caused by foreign matter such as a fallen brick.SOLUTION: An expansion joint, which is provided in piping for circulating high-temperature gas, absorbs displacement, which is associated with expansion and contraction caused by the thermal effect of the piping, by its own expansion and contraction. The expansion joint comprises a joint body which has an internal path connected to a channel of the piping and which can be connected between mutual end surfaces of the piping. A porous body, in which a plurality of openings enabling the passage of the high-temperature gas circulated through the channel of the piping is formed, is provided in the internal path of the joint body.SELECTED DRAWING: Figure 1

Description

The present invention relates to an expansion joint installed in a part of a piping system through which high-temperature gas flows.

The overall configuration of a typical blast furnace is schematically shown in FIG. 8, and the main parts of FIG. 8 are shown in enlarged form in FIG.

As shown in FIGS. 8 and 9, a plurality of tuyeres 9 are installed in the lower part of the blast furnace body along the rim of the blast furnace. The hot air passes through the flow paths of the upper hot air main pipe 11, the mixed cooling pipe 12, the lower hot air main pipe 13, and the annular pipe 14 in which refractories are arranged, and further passes through the upper bend 15, the telescopic pipe 16, and the spherical short pipe. 17, it is blown into the blast furnace from each tuyere 9 through the lower bend 18.

On the other hand, iron ore, coke, and auxiliary materials are charged from the top of the blast furnace, and are exposed to hot air (high-temperature reducing gas) blown from the tuyere 9 to promote reduction of the iron ore, etc. inside the blast furnace. , which is melted to produce pig iron.

Stable operation is one of the most important issues in blast furnace operation. If the blast furnace is unable to operate stably, a temporary shutdown may be carried out to temporarily stop blowing hot air. One of the causes of the temporary wind outage is that the tuyeres are clogged with bricks, etc.

This is because the bricks lined inside the piping for insulation purposes fall off in the hot air flow path (hot blast furnace - mixing chamber - annular pipe - tuyere), and these fallen bricks or their fragments are used to blow hot air into the hot air. This is caused by the water flowing downstream along with the water, and becoming blocked at the tip of the tuyere, which is the narrowest point in the channel.

In order to prevent such troubles, it is important to prevent bricks from falling off, and although sufficient measures have been taken to prevent bricks from falling off during the design and construction stages of blast furnaces and their ancillary equipment, In reality, it was not possible to completely prevent bricks from falling off.

Conventionally, as a method for preventing clogging of tuyere etc. caused by fallen or flying bricks, etc., as shown in FIG. It is known that a weir 19 is provided and the weir 19 prevents fallen brick pieces 20 from entering.

By the way, in the conventional method described above, the probability of the fallen bricks entering can be reduced to some extent, but when brick pieces 20 accumulate in front of the weir 19, the brick pieces 20 are climbed over the accumulated brick pieces 20 and another brick is placed. Since there is a concern that the pieces may enter the tuyere 9, it is necessary to check the accumulation of brick pieces 20 at the branch part of the annular pipe 14 and remove them. It is essential to remove other equipment such as the telescopic pipe 16 and the spherical short pipe 17 connected to the upper bend 15, which requires a large workload and is also dangerous as there is a risk that the weir 19 may fall during the removal work. It involved a lot of work.

In addition, as a prior art related to expansion joints, for example, the one disclosed in Patent Document 1 is referred to, but there is no mention of preventing clogging of tuyeres or clogging of piping systems due to fallen bricks. do not have.

Japanese Patent Application Publication No. 4-228509

An object of the present invention is to propose an expansion joint that can avoid clogging of piping systems and clogging of blast furnace tuyeres due to foreign objects such as fallen bricks.

As a result of various studies in order to prevent blockage of piping systems and clogging of blast furnace tuyeres due to foreign objects such as fallen bricks, the inventors solved the problem by focusing on expandable pipes installed in piping. This is what led to the solution. The expansion pipe is also called an expansion joint, and as exemplified in Patent Document 1, it is installed in a part of the piping system upstream of the tuyere of a blast furnace, and is used to control thermal expansion and contraction of the piping. It has the function of absorbing displacement caused by

That is, the present invention is an expansion joint that is installed in a pipe through which high-temperature gas flows, and absorbs displacement due to expansion and contraction of the pipe due to the influence of heat by its own expansion and contraction,
A joint body having an internal path connected to the flow path of the piping and connectable between the end faces of the piping, and allowing high-temperature gas flowing through the flow path of the piping to pass through the internal path of the joint body. This is an expansion joint characterized by providing a porous body in which a plurality of openings are formed.

In the expansion joint having the above configuration, the porous bodies have a shape convex toward the downstream side of the flow path, and the porous bodies are arranged at intervals along the axis of the joint body. Among the porous bodies in the multi-stage arrangement, the porous body located on the most upstream side of the internal path has the largest opening of the porous body located on any downstream side of the internal path. The joint body has an opening larger in size than the joint body, the joint body has a support portion on its inner wall surface that supports the porous body in at least two places, and the porous body can pass through the support portion. The support portion has a notch having a tapered tip in at least one of a shape in a plan view and a shape in a side view, and the joint body has a cover on a peripheral wall of the joint body. The joint body has a through opening that can be opened and closed through the porous body and allows the collected material collected by the porous body to be taken out to the outside, and the joint body is arranged to intersect with the axis of the joint body. an inner tube that is divided into at least two parts in a direction that intersects with the axis of the joint body and that are interconnected through a bellows; an outer tube surrounding the inner tube with a gap therebetween, the inner tube having an internal path through which the high-temperature gas passes, and the gap forming a flow path for the cooling water; In order to solve the problem, the inner pipe has a refractory on its inner wall surface, and further, the piping through which the high-temperature gas flows is an upper bend and a lower bend that connect the tuyere of the blast furnace and the annular pipe. This is preferable as a specific means.

According to the present invention, the bricks flying inside the pipe can be collected by the porous body installed inside the contraction joint, so that no blockage of the pipe system or clogging of the tuyere of the blast furnace occurs.

In particular, the expansion joint of the present invention is disposed between an upstream pipe connected to an annular pipe of a blast furnace and a downstream pipe connected to a blow pipe of a tuyere of a blast furnace, and the expansion joint of the present invention is arranged between the upstream pipe, the expansion joint, and the By blowing high-temperature gas supplied via the downstream piping into the blast furnace through the tuyere, it is possible to avoid temporary shutdown of the blast furnace due to clogging of the tuyere with brick pieces. Furthermore, since the tuyeres are often replaced in blast furnaces, brick pieces collected at the expansion joints can be easily recovered at that time.

1 is a diagram schematically showing an embodiment of an expansion joint according to the present invention, in which (a) is a plan view thereof, and (b) is a sectional view taken along line AA in (a). FIG. 3 is a diagram schematically showing another embodiment of an expansion joint according to the present invention. FIG. 7 is a diagram schematically showing still another embodiment of an expansion joint according to the present invention. FIG. 3 is a diagram schematically showing another embodiment of an expansion joint according to the present invention. FIG. 3 is a diagram schematically showing still another embodiment of an expansion joint according to the present invention, in which (a) is a plan view thereof, and (b) is a sectional view taken along line BB in (a). 6 is an explanatory diagram of how to attach a porous body in the expansion joint shown in FIG. 5. FIG. FIG. 3 is a diagram schematically showing another embodiment of an expansion joint according to the present invention, in which (a) is a plan view and (b) is a cross-sectional view taken along line CC in (a). FIG. 1 is a diagram schematically showing the overall configuration of a blast furnace. 9 is an enlarged view (partially shown in cross section) of the main part of FIG. 8. FIG.

Hereinafter, the present invention will be explained more specifically using the drawings.
1(a) and (b) are diagrams schematically showing an embodiment of an expansion joint according to the present invention, in which (a) is a plan view thereof, and (b) is an A of (a). -A sectional view.

Reference numeral 1 in FIGS. 1A and 1B represents a joint body that can be connected to the end faces of the upstream piping U1 and the downstream piping U2, respectively. In addition, in FIGS. 1(a) and (b), the high-temperature gas flows from the upstream pipe U1 to the downstream pipe U2 according to the arrow in FIG. 1(b), that is, from the top to the bottom of the page. It shall be distributed to

The joint body 1 is divided into two parts in a direction perpendicular to the axis L of the joint body 1, and includes inner pipes 1a and 1b that are interconnected via an airtight bellows B1, and an axis L of the joint body 1. It is divided into two parts in a direction perpendicular to L and is connected to each other via an airtight bellows B2, and is composed of outer pipes 1c and 1d surrounding the inner pipes 1a and 1b with a gap M in between, By appropriately expanding and contracting the bellows B1 and B2, displacements caused by expansion and contraction of the pipes U1 and U2 due to thermal effects are absorbed.

The inner tube 1a and the outer tube 1c, and the inner tube 1b and the outer tube 1d are integrally connected by flanges F1 and F2 provided at their ends (upper end, lower end), and the piping located on the upstream side The connection between U1 and the downstream piping U2 is performed via flanges F1 and F2 using fastening means such as bolts and nuts. In the illustrated example, the inner tubes 1a, 1b and the outer tubes 1c, 1d are each divided into two parts, but they may also be divided into three or more parts. , is not limited to two parts. The expansion joint according to the present invention has been shown as an example of a double pipe structure consisting of inner pipes 1a, 1b and outer pipes 1c, 1d, but it can also be applied to an expansion joint with a single pipe structure. can do.

Moreover, the symbols 2a and 2b in FIGS. 1A and 1B are cylindrical refractories provided on the inner wall surfaces of the inner tubes 1a and 1b. The inner space of the refractories 2a and 2b serves as an internal path N through which high-temperature gas (hot air, etc.) passes. A gap E is provided between the end surface 2a1 of the refractory 2a of the inner tube 1a and the end surface 2b1 of the refractory 2b of the inner tube 1b, and the expansion joint can expand and contract within the range of this gap E. become.

Further, reference numeral 3 in FIGS. 1(a) and 1(b) is arranged in the internal path N, and a plurality of openings are formed through which the high-temperature gas (hot air) flowing through the flow paths of the pipes U1 and U2 can pass through. It is a plate-shaped porous body. As the porous body 3, a metal plate or mesh, such as punched metal, wire mesh, expanded metal, etc., can be used.

Further, reference numeral 4 in FIGS. 1(a) and 1(b) is a support portion integrally provided on the inner wall surface of the inner tube 1a. The upper surface of the support part 4 is a support surface 4a, and the front side of the edge 3a of the porous body 3, in the illustrated example, the lower surface side of the edge 3a of the porous body 3 is brought into contact with the support surface 4a. Preferably, the porous body 3 is supported by being placed while being hooked onto the anchoring portion 4b. The support portion 4 and the edge portion 3a of the porous body 3 are embedded in the refractory 2a, and the support portion 4 is located at two opposing positions on the inner wall surface of the inner tube 1a, or at equal intervals around the inner wall surface. It can be provided in three or more locations.

In the expansion joint according to the present invention, since the porous body 3 is arranged in the internal path N of the joint body 1, it is possible to collect brick pieces flying inside the pipes U1 and U2 with the porous body 3. , it is possible to avoid clogging in the piping system and at the tuyeres.

As the porous body 3, it is preferable to use a heat-resistant metal, and the type and structure of the metal ( Determine the size of the openings, the spacing between the openings, and if wire mesh is used, the size of the openings and wire diameter, etc.

Note that, since the size of the opening of the porous body 3 also affects the ventilation resistance, the structure of the porous body 3 is selected in consideration of the ventilation resistance. Examples of specific porous bodies 3 that can be used under normal blast furnace operating conditions include wires made of heat-resistant stainless steel (SUS310S), SUH steel, and heat-resistant alloys with a wire diameter of about 3 to 20 mm and an opening of 5 mm. It is preferable to use a wire mesh with a thickness of about 50 mm. The opening of the wire mesh is preferably large enough to prevent foreign objects such as fallen bricks from passing through the wire mesh and clogging the inside of the pipe from the expansion joint to the tip of the tuyere. Further, in order to ensure the strength of the porous body 3, it is also possible to form a double structure by overlapping nets.

FIG. 2 is a diagram schematically showing another embodiment of the expansion joint according to the present invention. In this example, the porous body 3 has a concave shape toward the flow direction of the high-temperature gas, that is, a shape that is convex toward the downstream side of the flow path through which the high-temperature gas flows.

The shape of the porous body 3 is such that the center portion of the porous body 3 protrudes further toward the downstream side of the flow path through which high-temperature gas flows than the edge 3a of the porous body 3 supported by the support portion 4. It is preferable that As a result, the total area of the part through which high-temperature gas flows can be increased, and even if a large number of brick pieces, etc. fly in and are collected by the porous body 3, the flow path area of high-temperature gas decreases and the necessary flow rate is ensured. This has the advantage that the period until the flow rate of high-temperature gas decreases can be extended.

FIG. 3 is a diagram schematically showing still another embodiment according to the present invention. This example is based on a multi-stage arrangement in which two porous bodies 3, 3' each having a shape convex toward the downstream side of a flow path through which high-temperature gas flows are arranged at intervals along the axis L of the joint body 1. It is what it is. By arranging a plurality of porous bodies 3 at intervals, even if flying brick pieces pass through the porous body 3 located on the upstream side, the brick pieces can be removed by the porous body 3' located on the downstream side. can be collected.

When the porous bodies 3 and 3' are arranged in multiple stages, the supporting positions of the porous bodies 3 and 3' may be the same as shown in the figure, but the distance h between the parts located in the internal path N is The spacing may be such that the brick pieces can be held by the porous body 3' located on the downstream side.

When arranging the porous bodies 3 and 3' in multiple stages, the maximum passage size (maximum diameter of the opening) of the upstream porous body 3 is made larger than the maximum passage size of the downstream porous body 3'. Large-sized brick pieces can be collected by the upstream porous body 3, with a size between the maximum passage size of the upstream porous body 3 and the maximum passage size of the downstream porous body 3'. Bricks can be collected in the porous body 3' on the downstream side.

It is also possible to install three or more porous bodies 3, 3', and in this case, the maximum diameter of the opening of the most upstream porous body 3 is the maximum diameter of any of the downstream porous bodies 3'. If it is larger than the diameter, the above-mentioned function is exhibited, thereby suppressing the decrease in the flow path area in each porous body 3, 3' and further extending the period until the flow rate of high-temperature gas decreases. can.

4, 5(a) and 5(b) are diagrams schematically showing another embodiment of the expansion joint according to the present invention. In such an expansion joint, the tip portions 4c of the supporting portions 4 disposed opposite each other extend beyond the refractory 2a to the internal path N, and the edge portion 3a of the porous body 3 is connected to the support portion 4 of the support portion 4. It has a structure in which it is supported on a surface 4a via a mooring portion 4b.

In such a structure, for example, as shown in FIG. 5(a), two notches 3b are provided in the edge 3a of the porous body 3, the size of which is slightly larger than the width of the tip portion 4c of the support portion 4. As shown in FIG. 4c from the lower surface side to the upper surface side, and then, once the porous body 3 has passed through the tip portion 4c of the support part 4, the porous body 3 is rotated in the circumferential direction as shown by the arrow in FIG. 5(a). What is necessary is to shift the position of the notch portion 3b from the tip portion 4c of the support portion 4 and support the porous body 3 on the support surface 4a of the support portion 4. To remove the porous body 3 supported by the support part 4, rotate the porous body 3 in the opposite direction from when it was attached, and align the notch part 3b of the opposing body 3 with the tip part 4c of the support part 4. Thereafter, the porous body 3 is moved from the upper surface side of the support part 4 to the lower surface side.

Normally, in a blast furnace piping system, a lower bend 18 and a short spherical pipe 17, which are relatively easy to remove, are located downstream of the expansion joint, that is, on the tuyere side, as shown in FIG. When replacing the opening 9, the lower bend 18 and the spherical short pipe 17 must be removed. However, if the expansion joint according to the present invention is used, when the lower bend 18 and the spherical short pipe 17 are removed, the porous body 3 can be expanded and contracted. Since the joint can be easily removed from the downstream side, brick pieces collected by the porous body 3 can be removed, and the porous body 3 can also be replaced with a new porous body 3.

The support part 4 has a flat shape in a side view (cross-sectional shape) in which the thickness is the same from the proximal end connected to the inner tube 1a to the distal end portion 4c, as shown in FIG. In addition, as shown in FIGS. 5(a) and 5(b), the shape in plan view (indicated by virtual lines) and the shape in side view (cross-sectional shape) are tapered at the tip, i.e. It is preferable to use a material whose thickness gradually or stepwise becomes thinner from the proximal end connected to the inner tube 1a to the distal end portion 4c.By adopting such a shape, the support portion 4 can be attached to the inner tube 1a. It becomes easier to cool from the outside, and the heat resistance of the support part 4 improves.

FIG. 7 is a diagram schematically showing another embodiment of an expansion joint according to the present invention. Reference numeral 5 in FIG. 7 is a through hole provided in the inner pipe 1a constituting the peripheral wall of the joint body 1, 6 is a through hole provided in the refractory 2a and connected to the through hole 5, and 7 is a through hole provided in the joint body 1. A cylindrical body 8, which is connected to the circumferential wall of the inner tube 1a through the outer tube 1c and has a passage connected to the through holes 5 and 6, is a lid detachably provided at the end of the cylindrical body 7. be.

The through holes 5 and 6 and the passage of the cylindrical body 7 constitute a through opening through which brick pieces as a collection material collected by the porous body 3 are taken out to the outside, and when the blast furnace ventilation is stopped, etc. When the supply of hot air is stopped, the lid 8 is removed, the through opening is opened, and the brick pieces collected by the porous body 3 can be scraped out. In addition, in FIG. 7, in order to facilitate scraping out of the brick pieces collected by the porous body 3, a case where a plate-shaped porous body 3 is used is shown as an example. If scraping is possible, a porous body 3 as shown in FIG. 2 above may be used.

Cooling water can also be allowed to flow through the gap M formed between the inner tubes 1a, 1b and the outer tubes 1c, 1d. By circulating cooling water, it is possible to protect the expansion joint from the heat of the high-temperature gas flowing through the internal path N, and it is also possible to effectively cool the support section 4 that supports the porous body 3. .

By operating the blast furnace by providing an expansion joint according to the present invention between the upper vent and the lower vent connecting the annular pipe and the tuyere in the piping system for blowing hot air to the blast furnace, the blast furnace tuyere Although the expansion joint according to the present invention can be prevented from being clogged with brick pieces and enable stable blast furnace operation, the expansion joint according to the present invention can also be used in piping systems of equipment other than blast furnaces.

According to the present invention, it is possible to provide an expansion joint that can avoid clogging of piping systems or clogging of blast furnace tuyeres due to foreign objects such as fallen bricks.

1 Joint bodies 1a, 1b Inner tubes 1c, 1d Outer tubes 2a, 2b Refractories 3, 3' Porous body 3a Edge 3b Notch portion 4 Support portion 4a Support surface 4b Mooring portion 4c Tip portion 5 Through hole 6 Through hole 7 Cylindrical body 8 Cover body 9 Tuyere 10 Hot air stove 11 Upper hot air main pipe 12 Mixed cooling pipe 13 Lower hot air main pipe 14 Annular pipe 15 Upper bend 16 Telescopic pipe 17 Spherical short pipe 18 Lower bend 19 Weir 20 Brick piece U1 Upstream side Piping U2 Downstream piping B1, B2 Bellows M Gap F1, F2 Flange N Internal route E Gap h Spacing

Claims (11)

An expansion joint that is installed in a pipe that circulates high-temperature gas and absorbs displacement due to expansion and contraction of the pipe due to thermal effects by its own expansion and contraction,
A joint body having an internal path connected to the flow path of the piping and connectable between the end faces of the piping, and allowing high-temperature gas flowing through the flow path of the piping to pass through the internal path of the joint body. 1. An expansion joint comprising a porous body in which a plurality of openings are formed. The expansion joint according to claim 1, wherein the porous body has a shape that is convex toward the downstream side of the flow path. 3. The expansion joint according to claim 1, wherein the porous bodies are arranged in multiple stages arranged at intervals along the axis of the joint body. Among the porous bodies arranged in multiple stages, the porous body located on the most upstream side of the internal path has an opening larger than the maximum size of the opening of the porous body located on any downstream side of the internal path. 4. The expansion joint according to claim 3, wherein the expansion joint has a section. The expansion joint according to any one of claims 1 to 4, wherein the joint main body has support portions on its inner wall surface that support the porous body at at least two locations. 6. The expansion joint according to claim 5, wherein the porous body has a notch portion that allows the support portion to pass through. The expansion joint according to claim 5 or 6, wherein at least one of the shape in plan view and the shape in side view of the support portion has a tapered tip. The joint body is provided on the peripheral wall of the joint body so as to be openable and closable via a lid, and has a through opening that allows the collected material collected in the porous body to be taken out to the outside. The expansion joint according to any one of claims 1 to 7. The joint body is divided into at least two parts in a direction intersecting the axis of the joint body, and an inner pipe interconnected via a bellows, and at least two parts in a direction intersecting the axis of the joint body. , an outer tube that is interconnected via a bellows and surrounds the inner tube with a gap,
According to any one of claims 1 to 8, the inner tube has an internal path through which the high-temperature gas passes, and the gap forms a flow path for cooling water. expansion joint. The expansion joint according to claim 9, wherein the inner tube has a refractory material on its inner wall surface. The expansion joint according to any one of claims 1 to 10, wherein the piping through which the high-temperature gas flows is an upper bend and a lower bend that connect a tuyere of a blast furnace and an annular pipe.

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