JP2020084274A - Work environment temperature lowering method at the time of large-bell repair - Google Patents

Abstract

To lower the temperature in a region surrounded with a large-bell and a small-bell of a blast furnace early at the time of repair of the large-bell.SOLUTION: In the method for lowering work environment temperature during repair of a large-bell of a furnace-top charging apparatus of a bell-type blast furnace, the furnace-top charging apparatus includes a storage hopper for temporarily storing raw materials, a small-bell disposed below the storage hopper, and a large-bell disposed below the small bell. When the large-bell is repaired, the distance from the large-bell to a surface of charged raw materials in the furnace is set to 5 m or more and a portion of a bell hopper body in a second region between the large-bell and the small-bell, which is a work environment, is opened, and a first region between the small-bell and the storage hopper and the second region are allowed to communicate with each other.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a method for reducing the working environment temperature at the time of repairing a large bell, which reduces the atmospheric temperature of the working environment on the large bell at the time of repairing the large bell in a bell blast furnace.

In a blast furnace, raw materials such as iron ore and coke are charged from the upper part of the furnace, and high-temperature air and a reducing agent such as pulverized coal are blown from the tuyere at the lower part of the furnace to raise and reduce the temperature of the iron ore. Is a reaction vessel for producing. The bell-top blast furnace charging device is mainly a 2-bell 1-valve seal type consisting of two bells, a large bell and a small bell, and a seal valve. The large bell is usually made of low-alloy cast iron, and hardfacing or a liner material is attached to the portion where the falling raw material collides, as a measure against wear. However, even if such a countermeasure is taken, it is not possible to completely prevent the wear of the large bell, and the progress of wear deteriorates the distribution of the contents inside the furnace, which causes deterioration of the furnace condition. Therefore, when the large bell is worn, it is necessary to perform repair such as hardfacing welding or replacement of the liner material.

Regarding the repair of the large bell, for example, Patent Document 1 discloses a method for determining the repair time of the blast furnace large bell. Patent Document 2 discloses a liner used for repairing a large bell.

JP-A-6-287612 Japanese Utility Model Publication No. 7-2458

The repair of the large bell is performed by workers entering the area surrounded by the large bell and the small bell and working on the large bell when the blast furnace is off. When the blast furnace is operating, the ambient temperature on the large bell is 100°C or higher. The area surrounded by the large bell and the small bell has a narrow opening, and the atmosphere inside is likely to stay, so that the high temperature state is likely to continue. For this reason, the temperature in the area surrounded by the large bell and the small bell does not immediately drop even if the wind blows. When working in a high ambient temperature where the temperature does not drop sufficiently, the risk of heat stroke for workers increases, and it is difficult to continue for a long time and work is done while taking a break, so the repair time is long. become.

On the other hand, if the temperature in the area surrounded by the large bell and the small bell is lowered until the temperature environment is such that the load on the operator is low, and repairs are started, it will take time until the temperature drops and the blast furnace The rest time is long. If the blast furnace has a long blast time, there will be a large production loss, an increase in the amount of the reducing material for heat compensation during blast, and a concern that the operation will become unstable during startup. .. Therefore, there is a need for a technique for early reducing the temperature of the area surrounded by the large bell and the small bell.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to reduce the temperature of the area surrounded by the large bell and the small bell at an early stage during the repair of the large bell of the blast furnace. (EN) Provided is a new and improved method for reducing the working environment temperature when repairing a large bell.

In order to solve the above problems, according to an aspect of the present invention, there is provided a method for reducing a working environment temperature at the time of repairing a large bell in a furnace-top charging apparatus of a bell-type blast furnace, wherein the furnace-top charging apparatus is a raw material. A storage hopper for temporarily storing the storage bell, a small bell provided below the storage hopper, and a large bell provided below the small bell. A distance from the surface of the charging raw material in the furnace is set to 5 m or more, a part of the bell hopper body in the second region between the large bell and the small bell, which is the working environment, is opened, and the small bell is Provided is a method for reducing the working environment temperature at the time of repairing a large bell, which communicates the first region with the storage hopper with the second region.

A part of the bell hopper body in the first region may be opened to connect a suction device, the suction device may be operated, and forced exhaust may be performed from the second region communicating with the first region.

Further, a cold air supply device may be connected to a part of the bell hopper main body which is opened in the second region, and the cold air supply device may be operated to send the cool air to the second region.

As described above, according to the present invention, the temperature of the region surrounded by the large bell and the small bell can be reduced at an early stage when the large bell of the blast furnace is repaired.

It is a sectional view showing a schematic structure of a furnace top charging device of a bell type blast furnace concerning one embodiment of the present invention. It is explanatory drawing explaining the conventional large bell repair work. It is a flow chart which shows a work process of a work environment temperature reduction method at the time of repairing a large bell concerning this embodiment. It is explanatory drawing which shows the flow of the air of a blast furnace at the time of repairing the large bell which concerns on this embodiment. It is a graph which shows the relationship between the elapsed time after a breeze and the atmospheric temperature of a 2nd area|region when changing the distance H between a large bell and the charging raw material surface. It is explanatory drawing which shows the example which opened a part of 1st area|region enclosed by the small bell and the seal valve in the state of the furnace top charging device shown in FIG. 4, and installed the suction device. It is explanatory drawing which shows the example which installed the cold air supply apparatus in the opening part of the 2nd area|region in the state of the furnace top charging apparatus shown in FIG. It is explanatory drawing which shows the example which installed the suction apparatus and the cold air supply apparatus in the state of the furnace top charging apparatus shown in FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, constituent elements having substantially the same functional configuration are designated by the same reference numerals, and a duplicate description will be omitted.

<1. Configuration of Bell Top Blast Furnace Charging Equipment>
First, a schematic configuration of a bell-top charging device for a bell-type blast furnace according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view showing a schematic configuration of a bell-top charging device for a bell-type blast furnace according to this embodiment.

In a bell-type blast furnace, a furnace top charging device 1 for charging raw materials such as iron ore and coke from the furnace top is installed above a furnace body 9, and as shown in FIG. 1, a storage hopper 10 and a seal. It has a valve 20, a small bell cup 31, a large bell cup 33, a small bell 40, and a large bell 50.

The storage hopper 10 is provided at the top of the furnace and temporarily stores the raw material conveyed by a conveyor (not shown). The furnace top charging device 1 shown in FIG. 1 includes four storage hoppers 10. Two storage hoppers 10 are shown in FIG. The seal valve 20 is provided below the storage hopper 10 and partitions the storage hopper 10 and the small bell 40. By opening and closing the seal valve 20, the supply of the raw material stored in the storage hopper 10 onto the small bell 40 is controlled.

The small bell 40 and the large bell 50 are members that are provided in the bell hopper main body 3 of the blast furnace and are for charging the raw materials charged from the storage hopper 10 toward the furnace inner region in stages. The small bell 40 has a convex shape on the furnace top side, such as a substantially hemispherical shape or a conical shape shown in FIG. On the upper part of the small bell 40, a small bell rod 43 extends in the furnace height direction toward the furnace top. The small bell rod 43 is a hollow member. The small bell 40 is moved up and down in the furnace height direction by moving the small bell rod 43 up and down. The large bell 50 is provided below the small bell 40 and, like the small bell 40, has a shape that is convex toward the furnace top side, such as a substantially hemispherical shape or a conical shape shown in FIG. On the upper part of the large bell 50, a large bell rod 53 extends in the furnace height direction toward the furnace top. The large bell rod 53 is inserted into the small bell rod 43. The large bell 50 is moved up and down in the furnace height direction by moving the large bell rod 53 up and down.

Further, inside the bell hopper body 3, a small bell cup 31 is provided corresponding to the height position of the small bell 40 in the furnace height direction, and the small bell cup 31 is provided corresponding to the height position of the large bell 50. A cup 33 is provided. The area formed by the small bell 40, the small bell cup 31, the bell hopper body 3, and the seal valve 20 is referred to as a “first area A1”, and the large bell 50, the large bell cup 33, the bell hopper body 3, the small bell 40, A region formed by the small bell cup 31 is referred to as a “second region A2”.

The outer surface of the small bell 40 abuts the small bell cup 31 when rising, and separates the first area A1 and the second area A2. This state is also called a closed state. On the other hand, when the small bell 40 descends and the contact between the outer surface and the small bell cup 31 disappears, the first area A1 and the second area A2 are in communication with each other. Such a state is also referred to as an open state. Similarly, when the large bell 50 rises, the outer surface of the large bell 50 contacts the large bell cup 33 to separate the second area A2 from the furnace interior space A3. This state is also called a closed state. On the other hand, when the large bell 50 descends and contact between the outer surface and the large bell cup 33 disappears, the second region A2 and the furnace internal space A3 are in communication with each other. Such a state is also referred to as an open state.

In the first region A1, in the closed state, the internal pressure is increased to the internal pressure of the blast furnace. The raw material whose pressure has been increased to the pressure in the furnace of the blast furnace is charged into the second area A2 by lowering the small bell 40. The second region A2 is a region for storing the raw material whose pressure has been increased to the blast furnace pressure, and the large bell 50 is lowered to feed the raw material from the second region A2 to the in-furnace space A3.

Further, a manhole 3a is provided on a part of the side wall of the bell hopper body 3 in the second area A2 so as to be openable and closable with respect to the bell hopper body 3. When the manhole 3a is closed, the second area A2 is cut off from the outside, and when the manhole 3a is opened, the second area A2 is connected to the outside.

<2. Work environment temperature reduction when repairing large bell>
[2-1. Overview]
The repair of the large bell 50 is performed by the worker entering the second area A2, which is a working environment surrounded by the large bell 50 and the small bell 40, and working on the large bell 50 when the blast furnace is in a blast. As described above, the temperature of the second region A2 does not easily decrease, and it takes time for the worker to reach a temperature at which the worker can work for a long time.

In the conventional repair work of the large bell 50, for example, as shown in FIG. 2, after the blast furnace is blown off, the large bell 50 is first fixed in a closed state. Next, after the scaffolding material 7 is loaded from the storage hopper 10 into the small bell 40 in the closed state, the small bell 40 is opened and loaded into the large bell 50. The scaffolding material 7 loaded into the large bell 50 is spread on a portion other than the repaired portion on the large bell 50. Then, the repair work of the large bell 50 is performed in a state where the charging material surface 5a of the charging material 5 in the furnace is ignited (furnace top ignition). In addition, the furnace top fire is to detoxify the blast furnace gas (CO gas) remaining in the furnace (CO→CO ₂ ) when the blast furnace is blown off, so that the uppermost portion of the charging raw material 5 (that is, the surface of the charging raw material). 5a) ignites and burns blast furnace gas by inserting an ignition burner or by inserting a mallet or the like.

In order to lower the ambient temperature of the second area A2 surrounded by the large bell 50 and the small bell 40, it is first necessary to discharge the hot air from the area. Therefore, for example, the manhole 3a provided on the side wall of the bell hopper body 3 in the second area A2 is opened to take in the outside air into the second area A2, and the small bell 40 is opened so that the high temperature air in the second area A2 It is conceivable that the atmospheric temperature of the second region A2 is lowered by forming the discharge port. However, as a result of verification by the inventor of the present application, it was not possible to sufficiently lower the ambient temperature of the second region A2 only by such measures.

Therefore, as a result of investigating the cause that the atmospheric temperature of the second area A2 does not decrease, it was found that the large bell 50 is heated by the radiant heat due to the furnace top fire and the atmospheric temperature of the second area A2 is hard to decrease. The inventor of the present application has found from such knowledge that in order to lower the atmospheric temperature of the second region A2, it is necessary to secure the distance between the large bell 50 and the furnace top fire position at a predetermined distance or more. Hereinafter, the method for reducing the working environment temperature at the time of repairing the large bell according to the present embodiment will be described in detail.

[2-2. Working process]
A work environment temperature reduction method at the time of repairing a large bell according to the present embodiment will be described based on FIGS. 3 to 5. FIG. 3 is a flowchart showing the work steps of the work environment temperature reduction method at the time of repairing a large bell according to the present embodiment. FIG. 4 is an explanatory diagram showing the flow of air in the blast furnace at the time of repairing the large bell according to the present embodiment. FIG. 5 is a graph showing the relationship between the elapsed time after a breeze and the ambient temperature of the second region A2 when the distance H between the large bell 50 and the charging material surface 5a is changed. Note that FIG. 5 shows the relationship when the manhole 3a is open and the small bell 40 is in the open state.

First, as shown in FIG. 3, after a distance H between the large bell 50 and the charging material surface 5a of 5 m or more is secured, the air is blown off (S10). The distance H between the large bell 50 and the charging material surface 5a is the distance from the lower end of the large bell 50 to the charging material surface 5a, as shown in FIG. The height position of the charging raw material surface 5a may be the height position at the center of the blast furnace, or may be the average height position of the charging raw material surface 5a.

In the present embodiment, the target is to set the atmospheric temperature of the second region A2 to 40° C. or lower 12 hours after the blast furnace breeze. FIG. 5 shows the result of examination of the distance H required to achieve such a target. In FIG. 5, in each case where the distance H between the large bell 50 and the charging raw material surface 5a is set to 3 m, 4 m, 5 m, and 6 m, the manhole 3a provided on the side wall of the second area A2 is opened after a rest of air. And, the small bell 40 was opened, and the ambient temperature in the second region was measured. As a result, it is necessary to secure a distance H of 5 m or more between the large bell 50 and the surface 5a of the charging raw material in order to reduce the atmospheric temperature of the second region A2 to 40° C. or lower 12 hours after the blast furnace blast. all right.

Based on this result, in step S10, after the large bell 50 is closed and charging of the raw material to the bell hopper main body 3 is stopped, until the distance H between the large bell 50 and the charging raw material surface 5a becomes 5 m or more. stand by. Then, when the distance H between the large bell 50 and the charging material surface 5a becomes 5 m or more, the air blows off. Thereby, the radiant heat from the furnace top fire to the large bell 50 is suppressed, and the atmosphere temperature of the second region A2 can be suppressed from being kept high.

Next, the scaffolding material 7 is installed on the large bell 50 fixed in the closed state (S20). The scaffolding material 7 is loaded from the storage hopper 10 into the small bell 40 in the closed state, and then the small bell 40 is opened and loaded into the large bell 50. The scaffolding material 7 loaded into the large bell 50 is laid on a portion other than the repaired portion on the large bell 50. As the scaffolding material 7, for example, a raw material 5 for charging a blast furnace such as coke or the like is used.

Further, the small bell 40 is fixed in the open state, and the second area A2 and the first area A1 are communicated with each other (S30). At this time, the seal valve 20 is also opened. As a result, the air in the first area A1 moves to the second area A2 through the gap 37 between the small bell 40 and the small bell cup 31, and further moves to the outside from the storage hopper 10 through the seal valve 20. A flow path for is formed. Therefore, the outside air that has flowed into the second area A2 from the opening 35 of the manhole 3a is discharged from the second area A2 along the flow path.

Then, the furnace is ignited (S40), and the process waits until the atmospheric temperature of the second region A2 becomes equal to or lower than a predetermined temperature (S50). The predetermined temperature is a temperature at which the load on the worker P is small, and may be 40° C., for example. When it is determined in step S50 that the ambient temperature of the second area A2 is equal to or lower than the predetermined temperature, the worker P starts the repair work for the large bell 50 in the second area A2 (S60). The furnace top fire may be performed before S30.

The method for reducing the working environment temperature at the time of repairing the large bell according to the present embodiment has been described above. According to the present embodiment, when repairing the large bell 50, the manhole 3a is opened and the small bell 40 is opened with the distance H between the large bell 50 and the charging material surface 5a being 5 m or more. And Thereby, the influence of the radiant heat to the large bell 50 due to the furnace top fire is reduced, the ambient temperature of the second region A2 is easily lowered, and the second region A2, the first region A1, and the seal valve are opened from the opening 35. By forming a flow of air that passes through 20 toward the storage hopper 10, the high temperature air in the second region A2 is easily discharged. As a result, the temperature of the second region A2 surrounded by the large bell 50 and the small bell 40 can be reduced at an early stage.

[2-3. Modification]
As shown in FIG. 4, the manhole 3a is opened and the small bell 40 is opened in a state in which the distance H between the large bell 50 and the charging raw material surface 5a is 5 m or more. It is possible to effectively reduce the ambient temperature of the second area A2 when the bell is repaired. Further, in order to enhance the reduction effect, it is conceivable to form a stronger air flow or supply cold air. The details will be described below.

(1) Utilization of Suction Device FIG. 6 shows a state in which the furnace top charging device 1 shown in FIG. The example which installed the apparatus 60 is shown. The suction device 60 is, for example, a dust collector or the like, and is connected by a pipe 65 at the opening 39 of the first area A1. The suction device 60 may be installed and operated, for example, after the furnace top fire in step S40 shown in FIG. At this time, the seal valve 20 is closed. The distance H between the large bell 50 and the surface 5a of the charging raw material is also 5 m or more.

In this way, by operating the suction device 60 and sucking the air in the first region A1, the air flowing from the opening 35 into the second region A2 and the first region A1 flows toward the suction device 60. It can be formed stronger. Therefore, the hot air in the second area A2 is more easily discharged from the area.

(2) Use of Cold Air Supply Device FIG. 7 shows an example in which the cold air supply device 70 is installed in the opening 35 of the second area A2 in the state of the furnace top charging device 1 shown in FIG. The cold air supply device 70 is connected by a pipe 75 at the opening 35 of the second area A2. The installation and operation of the cold air supply device 70 may be performed, for example, after the furnace top fire in step S40 shown in FIG. The distance H between the large bell 50 and the surface 5a of the charging raw material is also 5 m or more.

In this way, by operating the cold air supply device 70 and supplying cold air to the second area A2, the storage hopper passes from the opening 35 through the second area A2, the first area A1, and the seal valve 20. The air flow toward 10 can be formed more strongly, and the hot air can be cooled more effectively. Therefore, the hot air in the second area A2 is more easily discharged from the area.

Further, the suction device 60 shown in FIG. 6 and the cold air supply device 70 shown in FIG. 7 may be used together. FIG. 8 shows an example in which the suction device 60 and the cold air supply device 70 are installed in the state of the furnace top charging device 1 shown in FIG. The suction device 60 and the cold air supply device 70 may be installed and operated, for example, after the furnace top fire in step S40 shown in FIG. At this time, the seal valve 20 is closed. The distance H between the large bell 50 and the surface 5a of the charging raw material is also 5 m or more.

In this case, by operating the cold air supply device 70 and supplying cold air to the second area A2, the high temperature air can be cooled more effectively. Further, by operating the suction device 60 and the cold air supply device 70, the flow of the air flowing into the second region A2 and the first region A1 from the opening portion 35 toward the suction device 60 can be further strengthened. it can. Therefore, the hot air in the second area A2 is more easily discharged from the area.

In order to verify the effect of the present invention, various settings are changed when the temperature in the second area surrounded by the large bell and the small bell, which is the work environment at the time of repairing the large bell, is changed to change the second area. The change in ambient temperature was investigated. In this verification, the distance H between the large bell and the surface of the charging raw material, the presence or absence of the opening of the second region (that is, the open/closed state of the manhole 3a in FIG. 1), the open/closed state of the small bell, the installation of the suction device and the cold air supply device. The presence/absence setting was changed. The atmospheric temperature was 25°C.

In Example 1, as shown in FIG. 4, the distance H between the large bell and the surface of the charging raw material was secured to be 5 m, and the atmosphere temperature in the second region was lowered in the state where the second region and the small bell were opened. Let At this time, the seal valve was opened.

In Example 2, as shown in FIG. 6, a distance H between the large bell and the surface of the charging raw material was secured to be 5 m, the second area and the small bell were opened, and a suction device was installed to make the second area. The ambient temperature of. At this time, the seal valve was closed.

In Example 3, as shown in FIG. 8, a distance H between the large bell and the surface of the charging raw material was 5 m, the second region and the small bell were opened, and a suction device and a cold air supply device were installed. , The ambient temperature of the second region was lowered. At this time, the seal valve was closed.

On the other hand, in Comparative Example 1, the distance H between the large bell and the surface of the charging raw material was secured to be 5 m, the small bell was opened to communicate the second region with the first region, and the suction device was installed in the first region. The ambient temperature in the two regions was lowered. In Comparative Example 1, the second region was not opened and the manhole 3a in FIG. 1 was in the closed state. Further, in Comparative Example 1, the cold air supply device was not installed.

In Comparative Example 2, the distance H between the large bell and the surface of the charging raw material was secured at 5 m, and the atmosphere temperature in the second region was lowered in a state where the second region was opened and the cold air supply device was installed. In Comparative Example 2, the small bell was not opened.

In Comparative Example 3, the distance H between the large bell and the surface of the charging raw material was set to 4.1 m and less than 5 m, and as shown in FIG. 8, the second region and the small bell were opened, and the suction device and the cold air supply device were used. Was installed to lower the ambient temperature of the second region. At this time, the seal valve was closed.

Regarding these Examples 1 to 3 and Comparative Examples 1 to 3, the atmospheric temperature of the second region was measured 12 hours after the breeze. The results are shown in Table 1. In this verification, the goal was to set the ambient temperature in the second region to 40° C. or lower 12 hours after the blast furnace was blown off.

As shown in Table 1, in each of Examples 1 to 3, the ambient temperature in the second region was 40° C. or lower 12 hours after the blast furnace was blown off. By providing the suction device as in the second embodiment, it is possible to further lower the ambient temperature in the second region, and by providing the cold air supply device in addition to the suction device as in the third embodiment, it is more effective. Therefore, the ambient temperature of the second region could be lowered.

On the other hand, in Comparative Example 1, the distance H between the large bell and the surface of the charging raw material was 5 m, and the small bell was in the open state, but the second region was not open. For this reason, the high temperature air in the second region was not effectively discharged, and the atmospheric temperature in the second region 12 hours after the blast furnace was blown off remained higher than 40°C.

Similarly in Comparative Example 2, the distance H between the large bell and the surface of the charging raw material was 5 m, and the second region was in the open state, but the small bell was not opened. For this reason, the high temperature air in the second region was not effectively discharged, and the atmospheric temperature in the second region 12 hours after the blast furnace was blown off remained higher than 40°C.

In Comparative Example 3, the second region and the small bell were in an open state, but the distance H between the large bell and the surface of the charging raw material was less than 5 m, so that due to the influence of the radiant heat to the large bell 50 due to the furnace top fire. The situation was such that the ambient temperature in the second region did not easily decrease. Therefore, the atmospheric temperature of the second region 12 hours after the blast furnace breeze remained higher than 40°C.

From the above, by keeping the distance H between the large bell and the surface of the charging material to be 5 m or more and opening the second area and the small bell, the temperature of the area surrounded by the large bell and the small bell can be promptly increased. It was shown to reduce.

Although the preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various alterations or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

1 Furnace Top Charging Device 3 Bell Hopper Main Body 3a Manhole 5 Charging Raw Material 5a Charging Raw Material Surface 7 Scaffolding Material 9 Furnace Body 10 Storage Hopper 20 Seal Valve 31 Small Bell Cup 33 Large Bell Cup 35, 39 Opening 37 37 Gap 40 Small Bell 43 Small bell rod 50 Large bell 53 Large bell rod 60 Suction device 65, 75 Piping 70 Cold air supply device

Claims (3)

A method for reducing the working environment temperature at the time of repairing a large bell in the furnace top charging device of a bell type blast furnace,
The furnace top charging device,
A storage hopper for temporarily storing raw materials,
A small bell provided below the storage hopper,
A large bell provided below the small bell,
Is equipped with
When repairing the large bell,
The distance between the large bell and the surface of the charging raw material in the furnace is 5 m or more,
A part of the bell hopper body in the second area between the large bell and the small bell, which is the working environment, is opened, and the first area and the second area between the small bell and the storage hopper are opened. A method for reducing the working environment temperature when repairing a large bell that connects the and. A part of the bell hopper body in the first region is opened to connect a suction device,
The method for reducing the working environment temperature at the time of repairing a large bell according to claim 1, wherein the suction device is operated to forcibly exhaust air from the second region communicating with the first region. A cold air supply device is connected to a part of the bell hopper body which is opened in the second region,
The work environment temperature reduction method at the time of repairing a large bell according to claim 1 or 2, wherein the cold air supply device is operated to send the cool air to the second region.

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