KR20220007016A - Hot-blast pipe and hot-blast stove - Google Patents

Abstract

The present invention relates to hot air pipes (21, 22, 23) for supplying hot air from hot air stoves (11, 12, 13) to a blast furnace (1), which comprise: hot air pipe main bodies (210, 220, 230); hot air valves (213, 223, 233) installed in the middle of the hot air pipe main bodies (210, 220, 230); flexible pipes (212, 222, 232) installed upstream compared to the hot air valves (213, 223, 233) of the hot air pipe main bodies (210, 220, 230); and pressure lines (51, 52, 53) for supplying high-pressure air which has higher pressure than the hot air passing through the hot air pipe main bodies (210, 220, 230) to the flexible pipes (212, 222, 232). The present invention provides the hot air pipe and the hot air stove, in which a problem of the flexible pipe due to hot air is prevented.

Description

HOT-BLAST PIPE AND HOT-BLAST STOVE

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

A hot stove is connected to the blast furnace through a hot air tube. A hot air valve and an expansion and contraction tube are provided in the middle of the hot air tube (see Document 1: Japanese Patent Laid-Open No. 62-267405). In such a hot air tube, the expansion and contraction tube can absorb thermal expansion at the time of operation switching of a hot air furnace, and can ensure the working clearance at the time of replacement|exchange of a hot air valve.

The inside of the hot air tube becomes high pressure due to the hot air during the blowing operation, and becomes low pressure because the hot air does not pass during the thermal storage operation. In the hot air tube of Document 1, a pressure equalization type having a pressure equalization chamber is used as the expansion tube, and the force in the expansion and contraction direction due to the pressure in the hot air tube is offset by the pressure of the pressure equalization chamber.

In the hot-air tube mentioned above, a heat-resistant brick is pasted inside the hot-air tube containing an expansion-contraction tube. However, the high-temperature, high-pressure hot air in the hot air tube may reach the hot air tube body through the gap between the heat-resistant bricks.

In order to enable expansion-contraction, a bellows-type elastic member is used for an expansion-contraction tube, and ceramic wool etc. which have flexibility are used as a fireproof member inside the bellows. Although ceramic wool is filled in the voids of the elastic member at the time of installation, it deteriorates and falls off with time, leaving voids. In such a space|gap part, there existed a problem that hot air flows in by the pressure fluctuation|variation between the blowing operation of a hot stove and a heat storage operation, and the surface of the elastic member becomes red by the high heat of the injected hot air.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hot air tube and a hot stove capable of preventing the problem of expansion and contraction tubes caused by hot air.

The hot air tube of the present invention is a hot air tube for supplying hot air from a hot stove to a blast furnace, comprising: a hot air tube body;

A hot air valve provided in the middle of the hot air tube body, an expansion tube provided on an upstream side of the hot air valve of the hot air tube body, and a pressurization line for supplying pressurized air higher than the hot air passing through the hot air tube body to the expansion tube It is characterized in that it has

In the present invention, the pressurized air supplied from the pressurization line maintains the inside of the expansion tube at a high pressure, and the hot air passing through the hot air tube can be prevented or suppressed from reaching the expansion tube through the brick gap. As a result, the influence by the hot air of an expansion-contraction tube can be prevented.

In the hot air tube of the present invention, it is preferable that the pressurization line has a check valve in the middle.

In this invention, even when there is an unintentional pressure drop of the pressurized air, it is possible to prevent the intrusion of the hot air from the hot air tube or the reverse flow to the supply source of the pressurized air.

In the hot air tube of the present invention, the pressurized air is preferably air for blowing which is supplied to the hot stove during the blowing operation of the hot stove.

In this invention, a dedicated pressurized air supply apparatus is unnecessary, and the simplification of apparatus structure can be aimed at. In addition, by using the same air for blowing, pressurized air higher in pressure than the hot air passing through the hot air tube body can be automatically supplied. That is, when the portion of the air for blowing air introduced into the hot stove reaches the expansion tube, only the pressure loss of the hot stove becomes low pressure. On the other hand, in the part used as pressurized air, the original pressure of the air for ventilation is maintained, and by this, it becomes high pressure automatically rather than the hot air passing through a hot-air tube main body.

In the hot air pipe of the present invention, a blow pipe for supplying the blowing air to the hot air pipe is connected to the hot air path, and a blow valve is installed in the middle of the blow pipe, and the pressurized air is supplied from the blow valve of the blow pipe. It is preferable to take out from the part up to the said hot stove.

In the present invention, pressurized air is automatically supplied from the blower pipe to the expansion pipe via the pressure line during the blowing operation in which the hot air is blown out from the hot stove. On the other hand, when the blowing for the blowing operation is stopped, the pressurized air to the pressurization line is automatically stopped. Therefore, the intermittent switching operation of the pressurized air can be automated.

In the hot air tube of the present invention, it is preferable that the pressurized air always flows during combustion and blowing of the hot air furnace.

In this invention, since pressurized air always flows in an expansion-contraction tube, even when the penetration of hot air from a brick gap arises suddenly, it can prevent reaching into an expansion-contraction tube reliably. In addition, for the pressurized air, the blowing air blown out from the upstream side rather than the blow valve of the blower pipe which supplies the blowing air to a hot stove can be used, For example, the blow blown out from the ventilation main pipe to which the blower pipe of each hot stove is connected. You can do it with air. When blowing out pressurized air from the upstream side of the blow valve of a blower pipe, it is preferable to provide a flow control valve or a pressure control valve to adjust a flow volume or pressure.

In the hot air tube of the present invention, the pressurized air is preferably at a lower temperature than the hot air passing through the hot air tube body.

In the present invention, when the pressurized air is supplied to the expansion tube, it is possible to prevent a decrease in strength due to the cooling of the pressurized air and the oxidization of the shells of the expansion tube and the hot air tube by high temperature, and it is possible to avoid deterioration of the piping and the like. The lower temperature than the hot air passing through the hot air tube main 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 more.

In this invention, with respect to the condensation of the supplied pressurized air, in particular, condensation of an acid can be aimed at, and corrosion of piping etc. can be avoided.

The hot stove of the present invention is a hot stove for supplying hot air to a blast furnace through a hot air tube, wherein the hot air tube includes a hot air tube body, a hot air valve installed in the middle of the hot air tube body, and the hot air valve of the hot air tube body It is characterized by having an expansion-contraction tube provided on the more upstream side, and a pressurization line which supplies pressurized air higher pressure than the inside of the said expansion-contraction tube to the said expansion-contraction tube.

In this invention, the effect as described in the hot air tube of this invention mentioned above can be acquired.

Advantageous Effects of Invention According to the present invention, it is possible to provide a hot air tube and a hot stove capable of preventing the problem of the expansion and contraction tube caused by hot air.

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows one Embodiment of the hot air tube and a hot stove of this invention.
Fig. 2 is an enlarged cross-sectional view showing the expansion and contraction tube in the embodiment.
3 : is a graph which shows each negative pressure in the said embodiment.
Fig. 4 is a plan view showing a hot air tube and a hot air stove according to another embodiment of the present invention.
Fig. 5 is a plan view showing a hot air tube and a hot air stove according to another embodiment of the present invention.

1 to 3, an embodiment of a hot air tube and a hot stove according to the present invention is shown.

In Fig. 1, the blast furnace 1 has an annular tube 3 around the furnace body 2, and the annular tube 3 and the furnace body 2 are connected by a plurality of twines. A hot air main tube 4 is connected to the annular tube 3 , and the hot air supplied from the hot air main tube 4 is blown into the furnace body 2 through a twist from the annular tube 3 .

A plurality of hot air passages 11 , 12 , 13 are provided along the hot air main building 4 .

In each of the hot stoves 11 , 12 , and 13 , a heat storage operation in which fuel gas is burned in the furnace to store heat in the heat storage bricks in the furnace, and the outdoor air introduced into the furnace is heated with the heat storage bricks to send hot air to the hot air main tube 4 . A blow operation that sends out is performed as a replacement.

Hot air tubes 21 , 22 , 23 are connected to the hot air passages 11 , 12 , and 13 in order to send out hot air to the hot air main tube 4 .

The hot air tubes 21 , 22 , and 23 are formed of hot air tube bodies 210 , 220 , 230 using steel pipes, and in the middle of the hot air tube main bodies 210 , 220 , 230 , mixing chambers 211 , 221 , 231 , respectively. ), expansion and contraction pipes 212 , 222 , 232 , and hot air valves 213 , 223 , 233 are provided.

The mixing chambers 211 , 221 , and 231 mix external air with the hot air from the hot stoves 11 , 12 , 13 and send out the hot air adjusted to a predetermined temperature.

Expansion tubes 212, 222, 232 absorb displacement in the axial direction and at right angles to the axis due to thermal expansion of the hot air tube body 210, 220, 230 and the mixing chamber 211, 221, 231, It is used to secure a working gap when replacing the hot air valves 213 , 223 and 233 .

The hot air valves 213 , 223 , and 233 conduct the hot air tube body 210 , 220 , 230 when the hot air path 11 , 12 , 13 blows, and during the heat storage operation, the hot air tube body 210 , 220 , 230 . ) can be abolished.

The hot air passages 11, 12, and 13 each include fire passage pipes 31, 32, 33 for exhausting combustion during thermal storage operation, and blower tubes 41, 42 and 43 for supplying pressurized air during ventilation operation, respectively. connected.

The fire passage pipes 31 , 32 , 33 are respectively connected to the fire passage main tube 38 , and the combustion exhaust from the hot stoves 11 , 12 , 13 can be discharged from the chimney 39 .

In the middle of the fire passage pipes 31, 32, 33, respectively, fire passage valves 311, 321, 331 are provided, and communication and closing from the hot stove 11, 12, 13 to the fire passage main pipe 38 are closed. switchable

The blast pipes 41 , 42 , 43 are respectively connected in the middle of the fire passage tubes 31 , 32 and 33 , and are connected to the hot air passages 11 , 12 , 13 via the fire passage tubes 31 , 32 and 33 , respectively. do.

The blower pipes 41 , 42 , 43 are respectively connected to the blower main pipe 48 , and can supply pressurized air from the blower 49 to the hot stoves 11 , 12 , 13 .

Blow valves 411 , 421 , 431 are respectively provided in the middle of the blower pipes 41 , 42 , and 43 , and communication and closing of the hot air passages 11 , 12 , 13 and the blower main pipe 48 can be switched.

A pressurization line ( 51, 52, 53) are divergent.

The pressurization lines 51 , 52 , 53 expand and contract pressurized air for blowing through the air pipes 41 , 42 , 43 , that is, pressurized air at a higher pressure than the hot air passing through the hot air tube body 210 , 220 , 230 , It is possible to supply the tube (212, 222, 232).

The pressure lines 51, 52, 53 are provided with check valves 511, 521, 531 on the way, and flow from the expansion and contraction pipes 212, 222, 232 to the blowing pipes 41, 42, 43 is prevented. .

2, the expansion and contraction tubes 212, 222, 232 of this embodiment are shown.

The expansion pipes 212, 222, and 232 are each formed of the same expansion pipe 60, and the hot air pipe body 210 on the upstream side connected to the hot air pipe body 61 (the hot stove 11, 12, 13). 220, 230) and the hot air tube main body 62 (the downstream hot air tube main body 210, 220, 230 connected to the hot air main tube 4) are connected.

The hot air tube main bodies 61 and 62 and the expansion and contraction tube 60 are each formed of a steel tube 63 having a circular cross section, and a fireproof material 64 is attached to the inside of the steel tube 63 . Flanges 65 are formed at the ends of the hot air tube main bodies 61 and 62 and the expansion and contraction tube 60, and are connected to each other by fastening the respective flanges 65 with bolts.

In addition to fastening the flange 65 with bolts, the hot air tube bodies 61 and 62 and the expansion tube 60 may be directly welded. The method of fastening the flange 65 has good workability, and the welding method has good preventing performance of hot air leakage.

On the inner side of the hot air tube main bodies 61 and 62 and the expansion and contraction tube 60 connected in series, along the inner surface of each fireproof material 64, fire bricks 66 (insulation bricks may be sufficient) are laminated|stacked. The hot air from the hot stoves 11, 12, 13 passes through the passage 67 formed inside these fire bricks 66. As shown in FIG.

In the expansion-contraction 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 60E are formed between the three cylinders 60A, 60B, and 60C, and the respective cylinders 60A, 60B, and 60C can be displaced in the axial direction and at right angles to each other in an axial direction.

The outer periphery of the cylinders 60A, 60B, and 60C is covered with a bellows 68 . The bellows 68 is formed as a corrugated tubular body, and while allowing displacement in the axial direction and at right angles to the axis of each tubular body 60A, 60B, 60C, the expansion pipe 60 through the gaps 60D and 60E. It is possible to block the distribution of the inside and outside.

The intermediate part of the bellows 68 is being fixed to the intermediate cylinder 60B by the fastener 681.

To the bellows 68, a pressurizing line 70 (pressurizing lines 51, 52, 53 in Fig. 1) is connected.

As described above, in the pressurization line 70 (pressurization lines 51, 52, 53), the hot air passing through the hot air tube body 210, 220, 230 (hot air passing through the passage 67) is pressurized at a higher pressure than that of the hot air. When air is supplied, the pressure of the internal space 682 of the bellows 68 can be made higher than the hot air passing through the passage 67 .

In addition, the pressurized air passing through the pressurization line 70 (pressurization lines 51, 52, 53) is lower temperature than the hot air passing through the hot air tube body 210, 220, 230 (hot air passing through the passage 67). of 350 degrees Celsius or less, and is also adjusted to 120 degrees Celsius or more.

At this time, the pressurized air from the blower 49 supplied to the blower main pipe 48 can be used as the pressurized air of 120 degrees Celsius or more at 350 degrees Celsius or less. This pressurized air is heated by adiabatic compression in the blower 49, and heating by a special heater or cooling by a radiator, etc. can be omitted in order to make the pressurized air from 350 degrees Celsius or less to 120 degrees Celsius or more.

3, in the hot stove S1, S2, and S3 (the hot stove 11, 12, 13 in FIG. 1) of this embodiment, as shown in the lower stage of FIG. Simultaneously, thermal storage operations C11, C12, and C13 are performed with the guitar.

For example, in hot stove S1 (hot stove 11 in FIG. 1), after making the inside of a furnace high enough by the heat storage operation C11, the ventilation operation H11 is started.

When starting the ventilation operation H11, the ventilation tube 41 and the hot air tube 21 are opened while closing the fire passage tube 31 of FIG. 1 . Thereby, the pressurized air supplied to the blower main pipe 48 is sent to the hot stove 11, and the hot air heated through the inside of the hot stove S1, S2, S3 is sent to the hot air pipe 21, and the blast furnace 1 ) is blown out. At the same time, a part of the pressurized air passing through the blower pipe 41 is supplied to the expansion pipe 212 through the pressurization line 51 .

When the predetermined time elapses, the blowing operation H11 by the hot stove S1 is finished, and the heat storage operation for two periods is started in the hot stove S1.

When the heat storage operation C11 is started, the fire passage pipe 31 of Fig. 1 is opened, the blower pipe 41 and the hot air pipe 21 are closed, the fuel is burned in the furnace to store heat, and exhaust gas is exhausted. is discharged from the fire passage pipe (31).

In the period of the heat storage operation C11 by the hot stove S1, the ventilation operation H12 by the hot stove S2 with heat storage completed in the heat storage operation C12 and the ventilation operation H13 by the hot stove S3 with the heat storage completed in the heat storage operation C13 are similarly performed.

For example, at the time of the blowing operation H11 by the hot stove S1, while hot air passes through the hot air tube 21, pressurized air from the pressurization line 51 is supplied to the expansion and contraction tube 212.

In the upper stage of FIG. 3, in the ventilation main pipe 48, it is hold|maintained substantially constant at the pressure P48 of pressurized air. In contrast, the pressure P21 of the hot air passing through the hot air tube 21 and the pressure P212 of the pressurized air passing through the pressurization line 51 rise with the start of the blowing operation, respectively, and are maintained constant during the blowing operation, and then blow the air. At the end of operation, the pressure returns to zero.

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 air blowing main pipe 48 due to a pressure loss when passing through the hot air path 11 . On the other hand, the pressure P212 of the pressurized air sent to the pressurization line 51 is maintained at a level slightly smaller than the pressure P48 of the blow main pipe 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 expansion and contraction 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 expansion tube 60 is pressure P21, whereas the pressurized air supplied from the pressure line 70 to the inner space 682 of the bellows 68 is pressure P212, Therefore, even if the hot air passing through the passage 67 of the expansion tube 60 tries to penetrate the internal space 682 through the gap between the fire bricks 66, it is blocked by the high-pressure air supplied to the internal space 682, Intrusion into space 682 is prevented.

According to this embodiment, the following effects can be obtained.

In the present embodiment, the pressure of the internal space 682 of the bellows 68 by the pressurized air supplied from the pressurization line 70 (51, 52, 53) to the expansion and contraction tube 60 (212, 222, 232). is maintained at a higher pressure than the hot air passing through the passage 67, and the hot air passing through the hot air tubes 21, 22, 23 (passage 67) passes through the gap between the fire bricks 66 and the expansion tube 60. It is possible to prevent or suppress reaching up to the steel pipe 63 or the bellows 68 . As a result, the influence of the hot air of the expansion and contraction tubes 212 , 222 , 232 can be prevented.

In the present embodiment, check valves 511 , 521 , 531 are provided in the middle of the pressurization lines 51 , 52 , 53 . For this reason, even when there is an unintentional pressure drop of the pressurized air supplied to the pressurization lines 51, 52, 53, the intrusion of hot air from the hot air tubes 21, 22, 23 or the blower tube ( 41, 42, 43) can be prevented.

In the present embodiment, as pressurized air supplied to the pressurization lines 51 , 52 , 53 , the blower pipe 41 supplied to the hot stove 11 , 12 , 13 during the blowing operation of the hot stove 11 , 12 , 13 . , 42, 43) was used for blowing air. For this reason, a dedicated pressurized air supply apparatus is unnecessary, and the simplification of apparatus structure can be aimed at.

In addition, by using the same air as the air for blowing supplied to the hot stove 11, 12, 13, higher pressure than the hot air passing from the hot stove 11, 12, 13 to the hot air tube body 210, 220, 230 Pressurized air can be supplied automatically.

That is, the portion of the air for blowing that passes through the blower tubes 41, 42, and 43, introduced into the hot air path 11, 12, 13, passes through the hot air tube body 210, 220, 230 and the expansion tube 212, When reaching 222, 232, the pressure becomes low by the pressure loss of the hot stove 11, 12, 13. On the other hand, in the portion used as pressurized air passing through the pressurization lines 51, 52, 53, the original pressure of the air for blowing in the blower pipes 41, 42, 43 is maintained, thereby maintaining the hot air pipe body 210 , 220, 230) automatically becomes higher pressure than the hot air through.

In the present embodiment, blow pipes 41 , 42 , 43 for supplying air for blowing to the hot stove 11 , 12 , 13 are connected to the hot stoves 11 , 12 , and 13 , and the blow pipes 41 , 42 , 43 are connected. ), blow valves 411, 421, 431 are provided in the middle, and the pressurized air sent to the pressure lines 51, 52, 53 is blown valves 411, 421, 431 of the blow pipes 41, 42, 43. to the hot stove (11, 12, 13) was taken out from the portion. For this reason, at the time of the blowing operation which sends out hot air from the hot air path 11, 12, 13, the expansion and contraction pipe|tube 212, 222, 232 from the blowing pipe 41, 42, 43 via the pressurization line 51, 52, 53. ) is automatically supplied with pressurized air. On the other hand, when the blowing for the blowing operation is stopped, the pressurized air to the pressurization lines 51, 52, 53 is automatically stopped. Therefore, the intermittent switching operation of the pressurized air can be automated.

In the present embodiment, the pressurized air supplied from the pressurizing lines 51 , 52 , 53 to the expansion and contraction tubes 212 , 222 , 232 is lower than the hot air passing through the hot air tube body 210 , 220 , 230 , that is, expansion and contraction. Since the pipes (212, 222, 232) and the steel pipe (63) are made at a low temperature of 350 degrees Celsius or less, which does not cause high temperature oxidation or strength reduction, expansion and contraction in pressurized air when supplied to the expansion pipes (212, 222, 232) High temperature of the pipes 212 , 222 , 232 and the steel pipe 63 can be prevented, and deterioration of the expansion and contraction pipes 212 , 222 , 232 and the steel pipe 63 can be avoided.

In addition, since the pressurized air from the pressurized lines 51, 52, and 53 is set to 120 degrees Celsius or more, it is important to prevent condensation of the pressurized air supplied to the expansion and contraction pipes 212, 222, and 232, in particular, to prevent acid condensation. This can be achieved, and corrosion of the steel pipe 63 can be avoided.

1 to 3, the pressurized air sent to the pressurization lines 51, 52, 53 is supplied from the blow valves 411, 421, 431 of the blow pipes 41, 42, 43 to the hot stove ( 11, 12, 13) were taken out, and it was made possible to automate the intermittent switching operation of pressurized air by this.

On the other hand, in the other embodiment of this invention shown in FIG. 4, the blowing of pressurized air has a different structure.

In FIG. 4, this embodiment is the same as that of embodiment of FIG. 1 mentioned above in a basic structure, The overlapping description about a common part is abbreviate|omitted, and a different part is demonstrated.

In the present embodiment, the hot air passages 11A, 12A, and 13A have hot air tubes 21A, 22A, and 23A, and the hot air tubes 21A, 22A, and 23A have pressurizing lines 51A, 52A, and 53A.

The pressurization lines 51A, 52A, 53A are respectively connected to the ventilation main pipe 48 , and can supply pressurized air blown out from the ventilation main pipe 48 to the expansion and contraction pipes 212 , 222 , 232 .

In the embodiment of Fig. 1 described above, the pressurized air in the pressurization lines 51, 52, 53 was also automatically interrupted in accordance with the interruption of the blow valves 411, 421, 431.

On the other hand, in this embodiment, since the blow main pipe 48 from which the pressurization lines 51A, 52A, 53A blows out the pressurized air is always considered to be a substantially constant pressure (pressure P48 in FIG. 3), at the time of a ventilation operation and heat storage By providing and controlling a flow rate control valve or a pressure control valve (not shown) to the expansion and contraction pipes 212 , 222 , and 232 without distinction during operation, substantially constant pressurized air is always supplied.

In this embodiment, since substantially constant pressurized air is always supplied from the pressurization lines 51A, 52A, 53A to the expansion and contraction pipes 212, 222, 232, it is a passage from the gap between the fire bricks 66 (refer to Fig. 2). Even when the hot air passing through (67) suddenly invades, it can be reliably prevented from reaching the steel pipe (63) or the bellows (68) of the expansion-contraction pipe (60).

In addition, this invention is not limited to the above-mentioned embodiment, The deformation|transformation etc. within the range which can achieve the objective of this invention are included in this invention.

Although the check valves 511, 521, 531 are provided in the pressurization lines 51, 52, 53, 51A, 52A, 53A in the said embodiment, you may select the valve structure and installation position suitably. In addition, providing the check valves 511, 521, 531 is not essential, and you may abbreviate|omit suitably.

In the above embodiment, the pressurized air sent to the pressurization lines 51, 52, 53, 51A, 52A, and 53A is supplied to each during the blowing operation of the hot stoves 11, 12, 13, 11A, 12A, and 13A. The ventilation air used was taken out from the ventilation pipes 41 , 42 , 43 or the ventilation main pipe 48 , and was used. On the other hand, a pressurized air supply device may be separately provided, and pressurized air of a required temperature, pressure, and air volume may be supplied to the pressurization lines 51, 52, 53, 51A, 52A, 53A.

In the above embodiment, the pressurized air supplied from the pressurization lines 51, 52, 53, 51A, 52A, 53A to the expansion and contraction tubes 212, 222, 232 is passed through the hot air tube body 210, 220, 230. Although it is lower temperature than hot air and it was set as 120 degreeC or more, for example, these temperature conditions may be relaxed as long as the dew condensation component in pressurized air can be removed in advance.

In the above embodiment, three hot stoves 11, 12, 13, 11A, 12A, and 13A are provided per one blast furnace, respectively, but the number may be two or four or more. The form of the hot stove 11, 12, 13, 11A, 12A, 13A is arbitrary, and an external combustion type or an internal combustion type can be used suitably.

In the above embodiment, the hot air tubes 21, 22, 23, 21A, 22A, and 23A are installed in the middle of the hot air tube body 210, 220, 230, respectively, in the mixing chambers 211, 221, 231, the expansion tube 212, 222, 232) and the hot air valves 213, 223, and 233 were arranged in this order. In such a configuration, the expansion and contraction tubes 212 , 222 , 232 are located on the upstream side of the hot air valves 213 , 223 and 233 , and in the state in which the hot air valves 213 , 223 , 233 are closed, they are not exposed to hot air and expand and contract. It is possible to work inside the tubes (212, 222, 232).

In the embodiment of FIG. 1 or the embodiment of FIG. 4 described above, the expansion and contraction tubes 212 , 222 , 232 are provided 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 , other expansion and contraction pipes 212B, 222B, 232B are provided between the mixing chambers 211 , 221 , 231 and the hot stove 11 , 12 , 13 . has been Pressurizing lines 51B, 52B, 53B branched from the pressurizing lines 51, 52, 53 (refer to Fig. 1) are connected to these expansion and contraction tubes 212B, 222B, and 232B, and pressurized air is supplied from each. .

A check valve (similar to the check valves 511, 521, 531 of FIG. 1) is provided in the pressurization lines 51B, 52B, and 53B, respectively. The pressure lines 51B, 52B, and 53B may branch from the pressure lines 51A, 52A, 53A (see FIG. 4 ).

In these other expansion and contraction pipes 212B, 222B, 232B, since there are no hot air valves 213, 223, 233 in the section, there is no need to consider the shrinkage value for valve replacement, and the number of breakage troubles is determined by the hot air valve 213, Although it is smaller than that of the expansion and contraction tubes 212 , 222 , 232 adjacent to 223 and 233 , it is possible to improve the displacement permissible performance of the hot air tube body 210 , 220 , 230 .

In each of the above-described embodiments, the hot stoves 11, 12, 13, 11A, 12A, and 13A are internal combustion hot air stoves in which the combustion chamber and the heat storage chamber are in the same container, but the external combustion hot air furnace is a container in which the combustion chamber and the heat storage chamber are independent. You can do it with Ro. At this time, although an expansion and contraction tube is provided in the piping connecting the combustion chamber and the heat storage chamber, you may apply the hot air tube of this invention to this expansion and contraction tube.

Claims (8)

It is a hot air tube that supplies hot air from the hot stove to the blast furnace,
The hot air tube body,
a hot air valve installed in the middle of the hot air tube body;
an expansion tube provided on an upstream side of the hot air valve of the hot air tube body;
and a pressurization line for supplying pressurized air higher in pressure than the hot air passing through the hot air tube body to the expansion and contraction tube. The hot air tube according to claim 1, wherein the pressurization line has a check valve in the middle. The hot air tube according to claim 1, wherein the pressurized air is air for blowing supplied to the hot stove during a blowing operation of the hot stove. According to claim 3, wherein the hot stove is connected to a blower pipe for supplying the air for blowing to the hot stove,
A blow valve is installed in the middle of the blower pipe,
The hot air tube is characterized in that the pressurized air is blown out from a portion of the air blower tube from the blow valve to the hot air passage. The hot air tube according to any one of claims 1 to 3, wherein the pressurized air always flows during combustion and blowing of the hot air stove. The hot air tube according to any one of claims 1 to 3, wherein the pressurized air is lower in temperature than the hot air passed through the hot air tube body. The hot air tube according to claim 6, wherein the pressurized air is 120 degrees Celsius or more. It is a hot air furnace that supplies hot air to the blast furnace through a hot air pipe.
The hot air tube is
The hot air tube body,
a hot air valve installed in the middle of the hot air tube body;
an expansion tube provided on an upstream side of the hot air valve of the hot air tube body;
A hot stove, characterized in that it has a pressurization line for supplying pressurized air at a higher pressure than the inside of the expansion tube to the expansion tube.

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