JP2022015632A - Hot blast tube and hot blast stove - Google Patents

Abstract

To provide a hot blast tube and a hot blast stove capable of preventing a failure in an expansion tube due to hot blast.SOLUTION: Hot blast tubes 21, 22, 23 for supplying hot blast from hot blast stoves 11, 12, 13 to a blast furnace 1 have hot blast tube bodies 210, 220, 230, hot blast valves 213, 223, 233 installed in the middle of the hot blast tube bodies 210, 220, 230, expansion tubes 212, 222, 232 installed on the upstream side of the hot blast valves 213, 223, 233 of the hot blast tube bodies 210, 220, 230, and pressure lines 51, 52, 53 for supplying pressurized air higher in pressure than the hot blast passed through the hot blast tube bodies 210, 220, 230 to the expansion tubes 212, 222, 232.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hot air tube and a hot air furnace.

A hot air furnace is connected to the blast furnace via a hot air pipe. A hot air valve and a telescopic pipe are installed in the middle of the hot air pipe (see Patent Document 1). In such a hot air pipe, the expansion pipe can absorb the thermal expansion when the operation of the hot air furnace is switched, and a work gap at the time of replacing the hot air valve can be secured.
The inside of the hot air pipe becomes high pressure due to the hot air during the blower operation, and becomes low pressure because the hot air does not pass during the heat storage operation. In the hot air tube of Patent Document 1, a pressure equalizing type having a pressure equalizing chamber is used as the expansion / contraction tube, and the force in the expansion / contraction direction due to the pressure in the hot air tube is canceled by the pressure of the pressure equalizing chamber.

Japanese Unexamined Patent Publication No. 62-267405

In the hot air pipe described above, heat-resistant bricks are stretched inside the hot air pipe including the expansion pipe. However, high-temperature and high-pressure hot air in the hot air pipe may reach the hot air pipe body through the gaps between the heat-resistant bricks.
A bellows-shaped expansion / contraction member such as a bellows is used for the expansion / contraction tube, and a flexible ceramic wool or the like is used as the fireproof member inside the expansion / contraction tube. The ceramic wool is filled in the voids of the elastic member at the time of installation, but deteriorates and falls off due to changes over time, leaving the voids. In such a gap, there is a problem that hot air flows in due to pressure fluctuations between the blowing operation and the heat storage operation of the hot air furnace, and the surface of the expansion / contraction member becomes reddish due to the high heat of the inflowing hot air.

An object of the present invention is to provide a hot air tube and a hot air furnace capable of preventing a malfunction of the expansion tube due to hot air.

The hot air pipe of the present invention is a hot air pipe that supplies hot air from a hot air furnace to a blast furnace, and has a hot air pipe main body and a hot air pipe main body.
A hot air valve installed in the middle of the hot air pipe body, an expansion tube installed upstream of the hot air valve of the hot air tube body, and pressurized air having a higher pressure than the hot air passed through the hot air tube body. It is characterized by having a pressurizing line for supplying the telescopic tube.
In the present invention as described above, the pressurized air supplied from the pressurizing line keeps the inside of the telescopic pipe at a high pressure, and can prevent or suppress the hot air passing through the hot air pipe from reaching the telescopic pipe through the brick gap. As a result, it is possible to prevent the influence of hot air from the expansion tube.

In the hot air tube of the present invention, it is preferable that the pressurizing line has a check valve in the middle.
In the present invention as described above, even if there is an unintended pressure drop of the pressurized air, it is possible to prevent the intrusion of the hot air from the hot air pipe or the backflow to the pressurized air source.

In the hot air pipe of the present invention, the pressurized air is preferably air for blowing air supplied to the hot air furnace during the blowing operation of the hot air furnace.
In the present invention as described above, a dedicated pressurized air supply device is not required, and the device configuration can be simplified. Further, by using the same air for blowing air, it is possible to automatically supply pressurized air having a higher pressure than the hot air passed through the hot air pipe main body. That is, the portion of the air for blowing that is introduced into the hot air furnace becomes low pressure by the pressure loss of the hot air furnace when it reaches the expansion pipe. On the other hand, the pressure of the original air for blowing is maintained for the amount used as the pressurized air, so that the pressure is automatically higher than that of the hot air passing through the hot air pipe main body.

In the hot air pipe of the present invention, a blower pipe for supplying the air for blowing to the hot air furnace is connected to the hot air furnace, a blower valve is installed in the middle of the blower pipe, and the pressurized air is the said. It is preferable that the air is taken out from the portion of the air pipe from the air valve to the hot air furnace.
In the present invention as described above, pressurized air is automatically supplied from the blower pipe to the expansion / contraction pipe via the pressurizing line during the blowing operation for blowing hot air from the hot air furnace. On the other hand, when the blowing for the blowing operation is stopped, the pressurized air to the pressurizing line is automatically stopped. Therefore, it is possible to automate the intermittent switching operation of the pressurized air.

In the hot air pipe of the present invention, it is preferable that the pressurized air is constantly flowed during combustion and blowing of the hot air furnace.
In the present invention as described above, since the pressurized air is constantly flowing through the telescopic pipe, even if hot air suddenly invades from the brick gap, it can be reliably prevented from reaching the telescopic pipe. As the pressurized air, the air for blowing air taken out from the upstream side of the blowing valve of the blowing pipe that supplies the air for blowing to the hot air furnace can be used. It can be the air for ventilation taken out from the pipe. When taking out pressurized air from the upstream side of the blower valve of the blower pipe, it is preferable to provide a flow rate control valve or a pressure control valve to adjust the flow rate or pressure.

In the hot air tube of the present invention, it is preferable that the pressurized air has a lower temperature than the hot air passed through the hot air tube main body.
In such an invention, the pressurized air is cooled when it is supplied to the telescopic pipe, and the iron skin of the telescopic pipe and the hot air pipe can be prevented from being oxidized by a high temperature to reduce the strength, and the deterioration of the pipe and the like can be prevented. It can be avoided. The temperature lower than that of the hot air passed through the hot air tube body is, for example, 350 degrees Celsius or less.

In the hot air tube of the present invention, the pressurized air is preferably 120 degrees Celsius or higher.
In such an invention, it is possible to prevent dew condensation of acid in particular with respect to dew condensation of the supplied pressurized air, and it is possible to avoid corrosion of pipes and the like.

The hot air furnace of the present invention is a hot air furnace that supplies hot air to the blast furnace through a hot air pipe, and the hot air pipe includes a hot air pipe main body, a hot air valve installed in the middle of the hot air pipe main body, and the hot air pipe main body. It is characterized by having a telescopic pipe installed on the upstream side of the hot air valve and a pressurizing line for supplying pressurized air having a higher pressure than the inside of the telescopic pipe to the telescopic pipe.
In the present invention as described above, the effects as described in the hot air tube of the present invention described above can be obtained.

According to the present invention, it is possible to provide a hot air tube and a hot air furnace that can prevent a malfunction of the expansion tube due to hot air.

The plan view which shows one Embodiment of the hot air tube and the hot air furnace of this invention. An enlarged sectional view showing a telescopic tube in the embodiment. The graph which shows the pressure of each part in the said embodiment. The plan view which shows the hot air tube and the hot air furnace of another embodiment of this invention. The plan view which shows the hot air tube and the hot air furnace of another embodiment of this invention.

1 to 3 show an embodiment of a hot air pipe and a hot air furnace of the present invention.
In FIG. 1, the blast furnace 1 has an annular pipe 3 around the furnace body 2, and the annular pipe 3 and the furnace body 2 are connected by a plurality of tuyere. The hot air main pipe 4 is connected to the annular pipe 3, and the hot air supplied from the hot air main pipe 4 is blown into the furnace body 2 from the annular pipe 3 through the tuyere.

A plurality of hot air furnaces 11, 12, and 13 are installed along the hot air main pipe 4.
In each of the hot air furnaces 11, 12, and 13, a heat storage operation is performed in which fuel gas is burned in the furnace to store heat in the heat storage brick in the furnace, and the outside air introduced in the furnace is heated by the heat storage brick to heat the hot air main 4 The operation of blowing hot air to the fire and the operation of blowing hot air are performed alternately.

Hot air pipes 21, 22, and 23 are connected to the hot air furnaces 11, 12, and 13 in order to send hot air to the hot air main pipe 4.
The hot air pipes 21, 22 and 23 are formed of hot air pipe main bodies 210, 220 and 230 using steel pipes, and in the middle of the hot air pipe main bodies 210, 220 and 230, mixing chambers 211, 22, 231 and expansion tube 212, respectively. , 222,232, and hot air valves 213,223,233 are installed.

The mixing chambers 211, 211, 231 mix the outside air with the hot air from the hot air furnaces 11, 12, and 13, and send out the hot air adjusted to a predetermined temperature.
The expansion tubes 212, 222, 232 absorb the displacements in the axial and perpendicular directions due to the thermal expansion of the hot air tube main body 210, 220, 230 and the mixing chambers 211, 221, 231 and the hot air valves 213, 223, 233. It is used to secure a work gap during replacement.
The hot air valves 213, 223, and 233 conduct the hot air pipe bodies 210, 220, 230 when the hot air furnaces 11, 12, and 13 are blown, and close the hot air pipe bodies 210, 220, 230 when the heat storage operation is performed. It is possible to do.

The hot air furnaces 11, 12, and 13 are connected to flue pipes 31, 32, 33 that perform combustion exhaust during heat storage operation and blower pipes 41, 42, 43 that supply pressurized air during blower operation, respectively. Has been done.
The flue pipes 31, 32, and 33 are connected to the flue main 38, respectively, and the combustion exhaust from the hot air furnaces 11, 12, and 13 can be discharged from the chimney 39.
Flue valves 311, 321, 331 are installed in the middle of the flue pipes 31, 32, 33, respectively, and communication and closure from the hot air furnaces 11, 12, and 13 to the flue main 38 can be switched.

The blower pipes 41, 42, 43 are connected in the middle of the flue pipes 31, 32, 33, respectively, and are connected to the hot air furnaces 11, 12, 13 via the flue pipes 31, 32, 33, respectively.
The blower pipes 41, 42, and 43 are connected to the blower main pipe 48, respectively, and pressurized air from the blower 49 can be supplied to the hot air furnaces 11, 12, and 13.
Blower valves 411, 421, 431 are installed in the middle of the blower pipes 41, 42, 43, respectively, and communication and closure of the hot air furnaces 11, 12, 13 and the blower main pipe 48 can be switched.

Pressurization lines 51, 52, 53 from the downstream side of the blower valves 41, 42, 43 of the blower pipes 41, 42, 43, that is, the flue pipes 31, 32, 33 side to the expansion pipes 212, 222, 232 branch. Has been done.
The pressurizing lines 51, 52, 53 supply the pressurized air for blowing through the blower pipes 41, 42, 43, that is, the pressurized air having a higher pressure than the hot air passed through the hot air pipe main bodies 210, 220, 230. , Can be supplied to the telescopic tubes 212, 222, 232.
Check valves 511, 521, 531 are installed in the pressurizing lines 51, 52, 53 in the middle to prevent distribution from the expansion pipes 212, 222, 232 to the blow pipes 41, 42, 43.

FIG. 2 shows the telescopic tubes 212, 222, 232 of the present embodiment.
The expansion tubes 212, 222, 232 are each formed of the same expansion tube 60, and the hot air tube main body 61 (upstream hot air tube main bodies 210, 220, 230 connected to the hot air furnaces 11, 12, and 13) and the hot air tube. It is connected to the main body 62 (the hot air pipe main bodies 210, 220, 230 on the downstream side connected to the hot air main pipe 4).

The hot air pipe main body 61 and 62 and the telescopic pipe 60 are each formed of a steel pipe 63 having a circular cross section, and a refractory material 64 is stretched inside the steel pipe 63. Flange 65s are formed at the ends of the hot air tube main bodies 61 and 62 and the expansion tube 60, and the flanges 65 are connected to each other by bolting them together.
In addition to fastening the flange 65 with bolts, the hot air pipe bodies 61 and 62 and the expansion pipe 60 may be directly welded. The method of fastening the flange 65 has good workability, and the welding method has good performance of preventing hot air leakage.
Refractory bricks 66 (which may be heat insulating bricks) are laminated along the inner surface of each refractory material 64 inside the hot air tube main bodies 61 and 62 and the expansion tube 60 connected in series. Hot air from the hot air furnaces 11, 12, and 13 is passed through the passage 67 formed inside the refractory bricks 66.

In the expansion pipe 60, the steel pipe 63 and the refractory material 64 are divided into three in the axial direction (flow direction Df in FIG. 2). Two gaps 60D and 60D are formed between the three cylinders 60A, 60B and 60C, and the cylinders 60A, 60B and 60C can be displaced from each other in the axial direction and the axis perpendicular method.
The outer periphery of the cylinders 60A, 60B, 60C is covered with bellows 68. The bellows 68 is formed of a bellows-shaped cylinder, and while allowing displacement in the axial direction and the axis perpendicular method of each cylinder 60A, 60B, 60C, it blocks the flow of the inner and outer surfaces of the expansion tube 60 through the gaps 60D and 60D. It is possible.
The middle portion of the bellows 68 is fixed to the middle cylinder 60B by the fixing tool 681.

A pressure line 70 (pressurization lines 51, 52, 53 in FIG. 1) is connected to the bellows 68.
As described above, the pressurized line 70 (pressurized lines 51, 52, 53) is supplied with pressurized air having a higher pressure than the hot air (hot air passing through the passage 67) passed through the hot air tube main bodies 210, 220, 230. Therefore, the pressure in the internal space 682 of the bellows 68 can be made higher than that of the hot air passing through the passage 67.

Further, the pressurized air passed through the pressurizing line 70 (pressurizing lines 51, 52, 53) is lower in degrees Celsius than the hot air passing through the hot air tube main bodies 210, 220, 230 (hot air passing through the passage 67). It is adjusted to 350 degrees or less and 120 degrees Celsius or more.
At this time, as the pressurized air at 350 degrees Celsius or less and 120 degrees Celsius or more, for example, the pressurized air from the blower 49 supplied to the blower main 48 can be used. This pressurized air is heated by adiabatic compression in the blower 49, and heating by a special heater or cooling by a radiator can be omitted in order to make the pressurized air at 350 degrees Celsius or less and 120 degrees Celsius or more. ..

As shown in the lower part of FIG. 3, in the hot air furnaces S1, S2, S3 of the present embodiment (hot air furnaces 11, 12, 13 in FIG. 1), the blower operation H11, H12, H13 is sequentially alternated by any one of them. At the same time, the heat storage operations C11, C12, and C13 are performed elsewhere.

For example, in the hot air furnace S1 (hot air furnace 11 in FIG. 1), the heat storage operation C11 raises the temperature inside the furnace to a sufficiently high temperature, and then the air blowing operation H11 is started.
When starting the blower operation H11, the flue pipe 31 of FIG. 1 is closed and the blower pipe 41 and the hot air pipe 21 are opened. As a result, the pressurized air supplied to the blower main 48 is sent to the hot air furnace 11, and the hot air heated through the hot air furnaces S1, S2, and S3 is sent out to the hot air pipe 21 and into the blast furnace 1. It is blown. At the same time, a part of the pressurized air passing through the blower pipe 41 is supplied to the telescopic pipe 212 through the pressure line 51.

After the predetermined time has elapsed, the blowing operation H11 by the hot air furnace S1 is terminated, and the heat storage operation for two periods is started in the hot air furnace S1.
When starting the heat storage operation C11, the flue pipe 31 of FIG. 1 is opened, the blow pipe 41 and the hot air pipe 21 are closed, the fuel is burned in the furnace to store heat, and the exhaust is discharged from the flue pipe 31. Discharge.
During the heat storage operation C11 by the hot air furnace S1, the air blowing operation H12 by the hot air furnace S2 that has already stored heat in the heat storage operation C12 and the air blowing operation H13 by the hot air furnace S3 that has already stored heat in the heat storage operation C13 are similarly performed.

For example, during the blowing operation H11 by the hot air furnace S1, the hot air is passed through the hot air pipe 21, and the pressurized air from the pressure line 51 is supplied to the expansion / contraction pipe 212.
In the upper part of FIG. 3, in the blower main 48, the pressure P48 of the pressurized air is maintained substantially constant. On the other hand, the pressure P21 of the hot air passing through the hot air pipe 21 and the pressure P212 of the pressurized air passing through the pressurizing line 51 increase with the start of the blowing operation, and are maintained constant during the blowing operation, and then blown. The pressure returns to 0 at the end of the operation.

Here, the pressure P21 of the hot air passing through the hot air pipe 21 becomes a value smaller than the pressure P48 of the blower main pipe 48 due to the pressure loss when passing through the hot air furnace 11. On the other hand, the pressure P212 of the pressurized air sent by the pressurizing line 51 is maintained to a degree slightly smaller than the pressure P48 of the blower main 48, and is sufficiently higher than the pressure P21 of the hot air passing through the hot air pipe 21.
As a result, in the telescopic tube 212, it is possible to prevent the high temperature and high pressure hot air passing through the hot air tube 21 from reaching near the surface.

In FIG. 2, the hot air passing through the passage 67 of the telescopic tube 60 has a pressure P21, whereas the pressurized air supplied from the pressurizing line 70 to the internal space 682 of the bellows 68 has a pressure P212, and therefore the telescopic tube 60. Even if the hot air passing through the passage 67 tries to enter the internal space 682 through the gap of the fireproof brick 66, it is blocked by the high pressure air supplied to the internal space 682 and prevented from entering the internal space 682. ..

According to such an embodiment, the following effects can be obtained.
In the present embodiment, the pressure in the internal space 682 of the bellows 68 is passed through the passage 67 by the pressurized air supplied from the pressurizing line 70 (51, 52, 53) to the expansion pipe 60 (212, 222, 232). It is possible to prevent or suppress the hot air passing through the hot air pipes 21, 22, 23 (passage 67) from reaching the steel pipe 63 and the bellows 68 of the expansion pipe 60 through the gaps of the refractory bricks 66 by keeping the pressure higher than that of the hot air. As a result, the influence of hot air on the expansion tubes 212, 222, 232 can be prevented.

In this embodiment, check valves 511, 521, 531 are provided in the middle of the pressurizing lines 51, 52, 53. Therefore, even if there is an unintended pressure drop of the pressurized air supplied to the pressurized lines 51, 52, 53, the hot air from the hot air pipes 21, 22, 23 invades or the blower pipe which is the pressurized air source. Backflow to 41, 42, 43 can be prevented.

In the present embodiment, as the pressurized air supplied to the pressurizing lines 51, 52, 53, the blower pipes 41, 42, which are supplied to the hot air furnaces 11, 12, 13 during the blower operation of the hot air furnaces 11, 12, 13. The air for blowing air passed through 43 was used. Therefore, a dedicated pressurized air supply device is not required, and the device configuration can be simplified.
Further, by using the same air as the air for blowing air supplied to the hot air furnaces 11, 12, 13, the pressure is higher than that of the hot air passed from the hot air furnaces 11, 12, 13 to the hot air pipe main bodies 210, 220, 230. Pressurized air can be supplied automatically.
That is, of the air for blowing air passed through the blowing pipes 41, 42, 43, the portion introduced into the hot air furnaces 11, 12, 13 passes through the hot air pipe main bodies 210, 220, 230 and the expansion pipes 212, 222. , 232, the pressure is reduced by the pressure loss of the hot air furnaces 11, 12, and 13. On the other hand, the amount used as pressurized air through the pressurized lines 51, 52, 53 maintains the original pressure of the air for blowing in the blowing pipes 41, 42, 43, whereby the hot air pipe main body 210 , 220, 230 automatically becomes higher pressure than hot air passing through.

In the present embodiment, the hot air furnaces 11, 12, and 13 are connected to the blower pipes 41, 42, 43 that supply the air for blowing to the hot air furnaces 11, 12, and 13, and are connected in the middle of the blower pipes 41, 42, 43. The blower valves 411,421,431 are installed, and the pressurized air sent to the pressurizing lines 51, 52, 53 is sent from the blower valves 411, 421, 431 of the blower pipes 41, 42, 43 to the hot air furnaces 11,12, It was made to be taken out from the part up to 13. Therefore, during the blowing operation for sending hot air from the hot air furnaces 11, 12, and 13, the pressurized air is automatically sent from the blower pipes 41, 42, 43 to the expansion pipes 212, 222, 232 via the pressure lines 51, 52, 53. Is supplied to. On the other hand, when the blowing for the blowing operation is stopped, the pressurized air to the pressurizing lines 51, 52, 53 is automatically stopped. Therefore, it is possible to automate the intermittent switching operation of the pressurized air.

In the present embodiment, the pressurized air supplied from the pressurizing lines 51, 52, 53 to the expansion pipes 212, 222, 232 is lower than the hot air passed through the hot air pipe main body 210, 220, 230, that is, the expansion pipe. Since the temperature of 212, 222, 232 and the steel pipe 63 is low at 350 degrees Celsius or less, which does not cause high temperature oxidation or decrease in strength, the expansion tube 212, which is supplied with pressurized air when supplied to the expansion tube 212, 222, 232, It is possible to prevent the temperature of 222,232 and the steel pipe 63 from becoming high, and it is possible to avoid deterioration of the telescopic pipe 212, 222,232 and the steel pipe 63.
Furthermore, since the pressurized air from the pressurized lines 51, 52, 53 is said to be 120 degrees Celsius or higher, the dew condensation of the pressurized air supplied to the expansion pipes 212, 222, 232 is particularly prevented from dew condensation of acid. This can be achieved, and corrosion of the steel pipe 63 can be avoided.

In the above-described embodiment of FIGS. 1 to 3, the pressurized air sent to the pressurizing lines 51, 52, 53 is sent from the blow valve 411, 421, 431 of the blower pipes 41, 42, 43 to the hot air furnace 11, 12, It was taken out from the parts up to 13 so that the operation of switching the intermittent switching of the pressurized air could be automated.
On the other hand, in another embodiment of the present invention shown in FIG. 4, the structure in which the pressurized air is taken out is different.

In FIG. 4, the basic configuration of the present embodiment is the same as that of the above-described embodiment of FIG. 1, and duplicate explanations of common parts will be omitted, and different parts will be described.
In the present embodiment, the hot air furnaces 11A, 12A, 13A have hot air pipes 21A, 22A, 23A, and the hot air pipes 21A, 22A, 23A have pressure lines 51A, 52A, 53A.
The pressurizing lines 51A, 52A, and 53A are connected to the blower main pipe 48, respectively, and the pressurized air taken out from the blower main pipe 48 can be supplied to the expansion pipes 212, 222, 232, respectively.

In the embodiment of FIG. 1 described above, the pressurized air in the pressurizing lines 51, 52, and 53 was automatically interrupted as the blower valves 411, 421, and 431 were interrupted.
On the other hand, in the present embodiment, the blower main pipe 48 from which the pressurizing lines 51A, 52A, and 53A take out the pressurized air always has a substantially constant pressure (pressure P48 in FIG. 3), so that during the blower operation and heat storage. By providing a flow control valve or a pressure control valve (not shown) in the expansion and contraction tubes 212, 222, 232 and controlling them regardless of the time of operation, substantially constant pressurized air is always supplied.

In such an embodiment, since substantially constant pressurized air is constantly supplied from the pressurizing lines 51A, 52A, 53A to the expansion pipes 212, 222, 232, through the gaps in the refractory bricks 66 (see FIG. 2). Even if hot air passing through the passage 67 suddenly enters, it can be surely prevented from reaching the steel pipe 63 and the bellows 68 of the telescopic pipe 60.

The present invention is not limited to the above-described embodiment, and modifications to the extent that the object of the present invention can be achieved are included in the present invention.
In the above embodiment, the check valves 511, 521, 531 are installed on the pressurizing lines 51, 52, 53, 51A, 52A, 53A, but the valve structure and the installation position may be appropriately selected. Further, it is not essential to provide the check valves 511, 521, 531 and may be omitted as appropriate.

In the above embodiment, as the pressurized air sent by the pressurized lines 51, 52, 53, 51A, 52A, 53A, the blown air supplied to each of the hot air furnaces 11, 12, 13, 11A, 12A, 13A during the blowing operation. Air was taken out from the blower pipes 41, 42, 43 or the blower main pipe 48 and used. On the other hand, a pressurized air supply device may be separately installed to supply pressurized air having a required temperature, pressure and air volume to the pressurized lines 51, 52, 53, 51A, 52A and 53A.

In the above embodiment, the pressurized air supplied from the pressurizing lines 51, 52, 53, 51A, 52A, 53A to the expansion and contraction tubes 212, 222, 232 is blown from the hot air passed through the hot air tube main body 210, 220, 230. Although it is said that the temperature is low and the temperature is 120 degrees Celsius or higher, for example, these temperature conditions may be relaxed as long as the dew condensation component in the pressurized air can be removed in advance.

In the above embodiment, three hot air furnaces 11, 12, 13, 11A, 12A, and 13A are installed per blast furnace, respectively, but the number may be two or four or more. The type of the hot air furnace 11, 12, 13, 11A, 12A, 13A is arbitrary, and an external combustion type or an internal combustion type can be appropriately used.
In the above embodiment, the hot air tubes 21,22,23,21A, 22A, 23A are placed in the middle of the hot air tube main bodies 210, 220, 230, respectively, with the mixing chamber 211,221,231, the expansion tube 212,222,232, and the hot air. The valves were arranged in the order of 213, 223, 233. In such a configuration, since the expansion and contraction pipes 212, 222, 232 are located on the upstream side of the hot air valve 213,223,233, the expansion and contraction without being exposed to hot air when the hot air valve 213,223,233 is closed. Internal work of pipes 212, 222, 232 is possible.

In the embodiment of FIG. 1 or FIG. 4 described above, the expansion pipes 212, 222, 232 were installed only between the mixing chambers 211,221,231 and the hot air valves 213,223,233.
On the other hand, in another embodiment of the present invention shown in FIG. 5, another expansion tube 212B, 222B, 232B is installed between the mixing chamber 211,221,231 and the hot air furnace 11, 12, 13. There is. Pressurized lines 51B, 52B, 53B branched from the pressurizing lines 51, 52, 53 (see FIG. 1) are connected to these telescopic tubes 212B, 222B, 232B, and pressurized air is supplied from each. There is.
Check valves (similar to the check valves 511, 521, 531 in FIG. 1) are installed in the pressure lines 51B, 52B, and 53B, respectively. The pressurizing lines 51B, 52B, 53B may be branched from the pressurizing lines 51A, 52A, 53A (see FIG. 4).
In such another expansion tube 212B, 222B, 232B, since there is no hot air valve 213,223,233 in the section, it is not necessary to consider the shrinkage allowance for valve replacement, and the number of breakage troubles is the hot air valve. Although it is less than the telescopic pipes 212, 222, 232 adjacent to 213, 223, and 233, the displacement tolerance performance of the hot air pipe main body 210, 220, 230 can be improved.

In each of the above-described embodiments, the hot air furnaces 11, 12, 13, 11A, 12A, and 13A are internal combustion type hot air furnaces in which the combustion chamber and the heat storage chamber are in the same container, but the combustion chamber and the heat storage chamber are independent. It may be an external combustion type hot air furnace which is a container. At this time, a telescopic pipe may be provided in the pipe connecting the combustion chamber and the heat storage chamber, and the hot air pipe of the present invention may be applied to this telescopic pipe.

The present invention can be used for hot air pipes and hot air furnaces.

1 ... blast furnace, 2 ... furnace body, 3 ... annular pipe, 4 ... hot air main pipe, 11, 11A, 12, 12A, 13, 13A ... hot air furnace, 21,21A, 22, 22A, 23, 23A ... hot air pipe, 210, 220, 230 ... Hot air tube body, 211,221,231 ... Mixing chamber, 212,212B, 222,222B, 232,232B ... Telescopic tube, 213,223,233 ... Hot air valve, 31,32,33 ... Smoke Pipe, 311, 321,331 ... Smoke valve, 38 ... Smoke main, 39 ... Chimney, 41, 42, 43 ... Blower, 411, 421, 431 ... Blower valve, 48 ... Blower main, 49 ... Blower, 51, 51A, 51B, 52, 52A, 52B, 53, 53A, 53B ... Pressurizing line, 511, 521, 531 ... Check valve, 60 ... Telescopic tube, 60A, 60B, 60C ... Cylinder, 60D, 60E ... Gap, 61, 62 ... Hot air pipe body, 63 ... Steel pipe, 64 ... Fireproof material, 65 ... Flange, 66 ... Fireproof brick, 67 ... Passage, 68 ... Bellows, 681 ... Fixture, 682 ... Internal space, 70 ... Pressurizing line, C11, C12, C13 ... Heat storage operation, Df ... Flow direction, H11, H12, H13 ... Blower operation,
P21 ... Hot air pipe pressure, P212 ... Pressurized line pressure, P48 ... Blower main pipe pressure, S1, S2, S3 ... Hot air furnace.

Claims (8)

A hot air pipe that supplies hot air from a hot air furnace to a blast furnace.
Hot air tube body and
With the hot air valve installed in the middle of the hot air pipe body,
A telescopic pipe installed on the upstream side of the hot air valve of the hot air pipe body, and
A hot air tube comprising a pressurizing line for supplying pressurized air having a pressure higher than that of hot air passed through the hot air tube main body to the telescopic tube. In the hot air tube according to claim 1,
The pressurizing line is a hot air pipe characterized by having a check valve in the middle. In the hot air tube according to claim 1 or 2.
The hot air pipe is characterized in that the pressurized air is air for blowing air supplied to the hot air furnace during the blowing operation of the hot air furnace. In the hot air tube according to claim 3,
A blower pipe for supplying the air for blowing to the hot air furnace is connected to the hot air furnace.
A blow valve is installed in the middle of the blower pipe.
The hot air pipe is characterized in that the pressurized air is taken out from a portion of the blower pipe from the blower valve to the hot air furnace. In the hot air tube according to any one of claims 1 to 3.
The hot air tube is characterized in that the pressurized air is constantly flowed during combustion and blowing of the hot air furnace. In the hot air tube according to any one of claims 1 to 5.
The hot air tube is characterized in that the pressurized air has a lower temperature than the hot air passed through the hot air tube main body. In the hot air tube according to claim 6,
The pressurized air is a hot air tube having a temperature of 120 degrees Celsius or higher. A hot air furnace that supplies hot air to the blast furnace through a hot air pipe.
The hot air tube is
Hot air tube body and
With the hot air valve installed in the middle of the hot air pipe body,
A telescopic pipe installed on the upstream side of the hot air valve of the hot air pipe body, and
A hot air furnace characterized by having a pressurizing line for supplying pressurized air having a higher pressure than the inside of the telescopic tube to the telescopic tube.

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