JP7445540B2 - Device to prevent spark scattering during gas cutting and method for dismantling towers and tanks - Google Patents

Description

The present invention relates to a spark scattering prevention device and a method for dismantling towers and tanks, which are used when performing gas cutting (gas cutting) of steel shells from the inside of towers and tanks installed in steel plants, chemical plants, etc., for example.

When dismantling hot blast furnaces (towers and tanks), which is a type of blast furnace equipment, when dismantling the steel shell that makes up the hot blast furnace, the steel shell is cut into rings using gas cutting and then lowered one by one using a crane. In this case, workers set up scaffolding (external scaffolding) outside the hot-air stove, which is approximately several tens of meters high, and cut the steel shell from outside the hot-air stove.
However, the above construction method has the following problems, for example.
- Construction time and costs will be incurred for assembling and dismantling the scaffolding.
・Ensuring safety is an issue because the work is done at height.
・Measures must be taken to prevent sparks from scattering.

By the way, when removing the bricks inside, there is a method for dismantling a hot air stove, such as suspending special equipment such as heavy machinery and a work deck from above, and removing the bricks one by one from the top (for example, , see Patent Document 1).

Japanese Patent Application Publication No. 8-260011

When using the above disassembly method to perform gas cutting to slice the steel shell from inside the hot blast stove, for example, the top surface of the bricks being removed can be used as a workshop, so it is necessary to erect scaffolding outside the hot blast stove. disappears. Therefore, it has the advantage of being surrounded by an iron shell, ensuring safety.
On the other hand, a large amount of sparks generated during gas cutting will be scattered outside the hot stove, so strict curing of sparks is required, for example, in steel plants where flammable materials are present.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a device for preventing spark scattering during gas cutting and a method for dismantling towers and tanks, which can minimize the installation of external scaffolding and improve workability and safety. With the goal.

The spark scattering prevention device during gas cutting according to the present invention, which achieves the above object, is a spark scattering prevention device used when performing gas cutting of the steel shell from the inside of a cylindrical tower tank equipped with the steel shell. hand,
The tower is attached to a plurality of through holes formed in the steel shell at intervals in the circumferential direction below the position of the steel shell where the gas cutting is performed, and is installed from inside the tower tank. a plurality of brackets that are arranged to protrude horizontally to the outside of the tanks and rotatably support rotating rollers;
A plurality of spark receiving means are sent out along the outer surface of the iron skin by the rotating roller, connectable to each other in the feeding direction, and receive sparks generated when the gas cutting of the iron skin is performed.

In the device for preventing sparks scattering during gas cutting according to the present invention, the rotating roller is movable in the axial direction of the bracket, and a locking portion is provided at the tip of the bracket, and the rotating roller is attached to the through hole. It is preferable that the spark receiving means on the rotating roller be drawn to the outer surface of the steel shell at the locking portion by pulling the base side of the bracket into the tower tank.

In the device for preventing sparks from scattering during gas cutting according to the present invention, the spark receiving means is provided with a spark receiving gutter serving as a bottom portion and a tip side of the spark receiving gutter, and is arranged to be inclined toward the outer surface of the iron skin. It is preferable to have a spark scattering prevention plate part.
Here, it is preferable that a scattering prevention auxiliary plate part made of an elastic body extends above the spark scattering prevention plate part.

In the spark scattering prevention device during gas cutting according to the present invention, it is preferable that a sealing member is provided on a surface of the spark receiving means that faces the outer surface of the iron skin.

In the apparatus for preventing spark scattering during gas cutting according to the present invention, it is preferable that the bracket is attachable to and detachable from the through hole.

A method for dismantling towers and tanks according to the present invention in accordance with the above object is a method for dismantling towers and tanks, which performs gas cutting of the steel shell from the inside of the cylindrical tower and tank, the method comprising:
a preparatory step of forming a plurality of through holes in the steel shell from inside the tower tank, below the position of the steel shell where the gas cutting is performed, and having intervals in the circumferential direction;
a roller bracket installation step of attaching a bracket that rotatably supports a rotary roller to each of the through holes from inside the towers and tanks so as to protrude horizontally to the outside of the towers and tanks;
A plurality of spark receiving means are sequentially placed from outside the towers and tanks on the rotating roller that protrudes outward from the towers and tanks, and adjacent spark receiving means are connected to each other, and the rotating roller a step of installing a spark receiving means to send out and arrange it along the outer surface of the iron skin;
The gas cutting step includes performing the gas cutting on the steel shell from inside the tower and tank, and receiving the generated sparks with the spark receiving means.

In the method for dismantling towers and tanks according to the present invention, in the spark receiving means installation step, the base side of the bracket attached to the through hole is pulled into the inside of the towers and tanks, and the spark receiving means installed at the tip of the bracket is pulled. It is preferable that the spark receiving means on the rotary roller be drawn to the outer surface of the iron shell by a locking portion such that a gap between the outer surface of the iron skin and the spark receiving means is eliminated.

In the method for dismantling towers and tanks according to the present invention, the spark receiving means is provided at the bottom of the spark receiving gutter and at the tip of the spark receiving gutter, and is inclined toward the outer surface of the iron shell. It is preferable to have a spark scattering prevention plate part.
Here, it is preferable that a scattering prevention auxiliary plate part made of an elastic body extends above the spark scattering prevention plate part.

In the method for dismantling towers and tanks according to the present invention, it is preferable that a sealing member is provided on a surface of the spark receiving means that faces the outer surface of the iron skin.

In the method for dismantling towers and tanks according to the present invention, it is preferable that the bracket is attachable to and detachable from the through hole.

A device for preventing spark scattering during gas cutting and a method for dismantling towers and tanks according to the present invention is such that a plurality of brackets rotatably supporting rotating rollers are connected to a plurality of through holes formed in a steel shell from inside the towers and tanks. At the same time, each spark receiving means is attached from the inside of the tower and tank, and the plurality of spark receiving means are sequentially placed on a rotating roller protruding outward from the tower and tank. Since the sending out is arranged along the surface, for example, only the scaffolding (new or existing scaffolding) for carrying out the work of placing, connecting, and sending out multiple spark receiving means is placed outside the towers and tanks. Since it is only necessary, the installation of external scaffolding can be minimized.
Furthermore, since gas cutting of steel shells can be carried out from inside the towers and tanks, it is less affected by typhoons, strong winds, gusts, etc., and the work efficiency is improved compared to when cutting from the outside of the towers and tanks. and safety can be improved.

(A) to (C) are explanatory diagrams of a method for dismantling towers and tanks according to an embodiment of the present invention. (A) is an explanatory diagram of a roller bracket of a device for preventing sparks scattering during gas cutting applied to a method for dismantling towers and tanks, and (B) is a cross-sectional view taken along the line a-a in (A). (A) is a plan view of the spark receiving means of the spark scattering prevention device during gas cutting, (B) is a sectional view taken along the line bb of (A), and (C) is a side view. FIG. 2 is an explanatory diagram of a method for dismantling towers and tanks according to an embodiment of the present invention. FIG. 5 is a plan view of FIG. 4; 6 is a partially enlarged view of FIG. 5. FIG. FIG. 3 is an explanatory diagram after the step of installing a spark receiving means in the method for dismantling towers and tanks according to an embodiment of the present invention.

Next, embodiments embodying the present invention will be described with reference to the attached drawings to provide an understanding of the present invention.
As shown in FIGS. 1 to 7, a spark scattering prevention device (hereinafter also simply referred to as a spark scattering prevention device) 10 during gas cutting according to an embodiment of the present invention is a tower tank equipped with an iron shell 11. (etc.) This is a device used when performing gas cutting (gas cutting) of the steel skin 11 from the inside of the steel shell 12, and can minimize the need for external scaffolding, improving work efficiency and safety.
This will be explained in detail below.

As shown in FIGS. 4 and 5, the towers and tanks 12 are, for example, cylindrical with a height of several meters to several tens of meters, and the outside is made of an iron shell 11 (for example, made of steel plate and has a thickness of 10 to 30 mm), and the inside of this steel shell 11 is hollow (hollow structure, that is, the steel shell is also cylindrical), but depending on the type of tower or tank, there may be a structure inside the steel shell. (e.g., inner tube, deck, ladder, etc.) may also be present.
Such towers and tanks include, for example, heating furnaces and hot blast furnaces installed in steel plants, reaction towers and chimneys installed in chemical plants, but the exterior is made of iron shell. If so, it is not particularly limited.

As shown in FIGS. 1 to 7, the spark scattering prevention device 10 is supported by a plurality of roller brackets 16 installed radially outward of the iron shell 11, and is supported by the roller brackets 16. It has a plurality of spark receiving means 17 that are sent out and arranged along the outer surface of the skin 11 (here, one spark receiving means is provided by two (or a plurality of three or more) roller brackets 16). 17 is supported).
As shown in FIGS. 1(A) to 1(C), the plurality of roller brackets 16 are located below the position L where gas cutting of the steel shell 11 is performed (for example, at a position approximately 50 mm to 200 mm below the position L, here). The rollers are installed from inside the towers and tanks 12 into a plurality of through holes 18 with circular cross sections formed in the steel shell 11 at intervals of 110 mm in the circumferential direction. The bracket 16 has a bracket 19 and a rotating roller 20.

The bracket 19 is a steel bar with a circular cross section, as shown in FIGS. 1(A) to (C), and FIGS. 2(A) and (B). A locking portion 21 is provided at the tip of the locking portion 21 to project upward, and has a hook shape (horizontal L-shape) when viewed from the side.
A fixing boss 22 with a circular cross section is provided at an intermediate position in the axial direction of the bracket 19, and the fixing boss 22 has a circular cross section and is inserted into the bracket 19 so as to be able to move forward and backward in the horizontal direction. 23 are provided. The fixing boss 22 has an outer diameter that allows it to be inserted into the through hole 18 formed in the iron shell 11 with a small gap (for example, about 1 mm), and the cotter 24 that is driven into the upper part of the fixing boss 22 has a small gap (for example, about 1 mm). As a result, the fixing boss 22 can be attached and fixed to the through hole 18. Furthermore, the stopper portion 23 can prevent the fixing boss 22 from falling to the outside of the towers and tanks 12 and position the fixing boss 22 with respect to the through hole 18 .

A nut member 25 is screwed into the bracket 19 on the base side of the fixing boss 22, and a ring-shaped wire (relatively soft iron wire) 26 is attached to the base of the bracket 19. Since the wire 26 is attached to the bracket 19 in a vertical plane, for example, by attaching a mark to the top of the wire 26, the locking portion 21 can be removed from the inside of the towers and tanks 12. Even if it cannot be confirmed, the orientation of the locking portion 21 (that is, upward) can be determined. Note that a mark may be attached to the base side of the bracket 19 so that the orientation of the locking portion 21 can be recognized.
In use, the bracket 19 can be pulled into the towers and tanks 12 by pulling the wire 26, and the bracket 19 can be further pulled in by turning the nut member 25.

A rotating roller 20 is attached to the bracket 19 on the side beyond the fixing boss 22 (between the fixing boss 22 and the locking part 21).
The rotating roller 20 is made of SGP piping (carbon steel pipe for piping), and ball bearings 27 are attached to the inside of both ends in the axial direction. As a result, the rotating roller 20 is supported by the bracket 19 and can rotate around the bracket 19, and can also move forward and backward in the axial direction of the bracket 19.
Note that since the outer diameter of the rotating roller 20 is smaller than the inner diameter of the through hole 18 formed in the steel shell 11, the rotating roller 20 can be moved from the inside of the towers and tanks 12 to the outside through the through hole 18, or , can be inserted from the outside to the inside.

As shown in FIGS. 3A to 3C, the spark receiving means 17 includes a spark receiving gutter 28 serving as a bottom portion and a spark scattering prevention plate portion 29 provided on the tip side of the spark receiving gutter 28. ing.
The spark receiving trough 28 is made of steel to catch the falling sparks generated during gas cutting of the steel skin 11, and includes a bottom plate portion 30 which is approximately rectangular in plan view, and a base side (iron side) of the bottom plate portion 30. The base plate part 31 is erected (the part located on the skin 11 side), and the base plate part 31 is installed upright on both sides of the bottom plate part 30 (both sides in the circumferential direction of the iron skin 11), and is V-shaped when viewed from the side. side plate portions 32 and 33.
Since this spark receiving trough 28 is arranged along the outer surface of the iron shell 11, as shown in FIG. The shape of the iron shell 11 in plan view is also an arcuate shape corresponding to the outer surface of the iron skin 11.

Note that, as shown in FIGS. 1(B) and 1(C), a sealing member (gap filling member) 34 is provided on the outer surface of the base plate portion 31, which is the surface facing the outer surface of the iron skin 11. There is. This sealing member 34 is made of, for example, a flexible material (for example, about 5 mm to 20 mm thick) made of non-combustible (fire-resistant) ceramic fibers intertwined in a complicated manner and formed into a blanket shape. Can be used.
As a result, even if a gap or the like occurs between the outer surface of the iron shell 11 and the spark receiving means 17 due to the surface condition of the iron shell 11 or the shape of the base plate portion 31, the sealing member 34 can close the gap. It can be eliminated. Therefore, generated sparks can be prevented from falling downward from between the outer surface of the iron skin 11 and the spark receiving means 17.

A spark scattering prevention plate portion 29 is provided at a position facing the base plate portion 31 of the spark receiving trough 28 .
The spark scattering prevention plate part 29 is made of steel to suppress and further prevent the scattering of sparks generated during gas cutting of the steel shell 11, and its lower end is connected to the front end of the bottom plate part 30. It is attached and fixed, and its both end portions are attached and fixed to the other sides of both side plate portions 32 and 33 that constitute the spark receiving trough 28.
Therefore, the spark scattering prevention plate portion 29 is inclined toward the outer surface of the iron skin 11 with its lower end portion as a base point.

Furthermore, an auxiliary scattering prevention plate section 35 is extended above the spark scattering prevention plate section 29 .
The scattering prevention auxiliary plate part 35 is made of wire mesh with a fine mesh (for example, 80 mesh or more (opening 0.2 mm or less), here 100 mesh (opening 0.154 mm)). Note that when installing the spark receiving means 17 (during gas cutting), as shown in FIG. , for example, about 50 mm to 150 mm.
In this way, the reason why the scattering prevention auxiliary plate part 35 is made of a wire mesh, which is an elastic body, is to prevent the cylindrical steel shell part from lifting upward when the steel shell part is separated into cylindrical pieces by gas cutting. This is to allow the scattering prevention auxiliary plate part 35 to return to its original shape without being damaged even if it comes into contact with the scattering prevention auxiliary plate part 35 in the lateral direction and is deformed.

The size of the spark receiving means 17 described above is not particularly limited as long as it can prevent the generated sparks from scattering, but can be set within the following range, for example.
The radial width W of the spark receiving gutter 28 (bottom plate portion 30) is, for example, about 200 mm to 400 mm (here, about 300 mm), and the height from the bottom plate portion 30 to the upper end of the scattering prevention auxiliary plate portion 35 is: For example, it is about 300 mm to 500 mm (here, about 400 mm).
Further, the inclination angle θ1 of the spark scattering prevention plate portion 29 with respect to the bottom plate portion 30 (horizontal surface) of the spark receiving trough 28 is preferably set to, for example, about 45 to 80 degrees (here, 60 degrees). The scattering prevention auxiliary plate part 35 is inclined further toward the outer surface of the steel shell 11 than the spark scattering prevention plate part 29 (the inclination angle θ2 of the scattering prevention auxiliary plate part 35 with respect to the horizontal plane is equal to the inclination angle θ1 Although it is smaller, about 35 to 55 degrees (here, 45 degrees), it may be arranged on the same plane as the spark scattering prevention plate part 29 (ie, θ1=θ2).

A plurality of connecting through holes 36 are formed in the side plate portions 32 and 33 of the spark receiving gutter 28, as shown in FIGS. 1(B), 3(C), and 3(C). As a result, the spark receiving troughs 28 adjacent to each other in the feeding direction along the outer surface of the steel shell 11 by the rotating roller 20 of the roller bracket 16 are connected to each other by, for example, a connecting means (not shown) consisting of bolts and nuts. Can be connected.
Therefore, since the adjacent spark receiving means 17 (spark receiving gutter 28, powder scattering prevention plate part 29, and scattering prevention auxiliary plate part 35) can be connected to each other without any gaps, between the adjacent spark receiving means 17 This prevents sparks from falling from the ground.
Here, the bottom plate part 30, the base plate part 31, and the side plate parts 32, 33 that constitute the spark catch gutter 28 and the spark scattering prevention plate part 29 are each formed separately and integrated by welding or the like. However, they can also be formed by punching out a steel plate in the unfolded state and bending it.

Next, a method for dismantling towers and tanks according to an embodiment of the present invention will be described.
4 and 5, the method for dismantling towers and tanks 12 that performs gas cutting of the steel shell 11 from the inside of the towers and tanks 12 equipped with the steel shell 11 includes a preparation process, a roller bracket installation process, and a spark catching means installation process. This method includes a gas cutting process, a gas cutting process, and a post-process, and the installation of external scaffolding can be minimized, improving workability and safety.

(preparation process)
First, a worker (not shown) sets up a scaffold 40 inside the towers and tanks 12. This scaffold 40 is provided, for example, by stacking upper and lower scaffold sets 43, each of which is a set of an upper scaffold 41 and a lower scaffold 42, which are frame scaffolds, in multiple stages. Note that if there are structures (inner cylinder, deck, ladder, etc.) inside the towers and tanks 12, the scaffolding 40 is installed after these are removed first.
Each of the upper and lower scaffold sets 43 is configured, for example, by placing a work floor 45 on a scaffold framework 44, and an elevating staircase 46 is provided in the center of the scaffold framework 44 when viewed from above. Further, the scaffolding framework 44 can be fixed in contact with the inner circumferential surface of the towers and tanks 12. Note that the scaffold is not limited to the above-mentioned framework scaffold, but a so-called single-tube scaffold can also be used.

After the above-mentioned scaffold 40 is installed inside the towers and tanks 12 up to the vicinity of its top, a worker moves the steel shell 11 from inside the towers and tanks 12 to the steel shell 11, as shown in FIG. 1(A). A plurality of through holes 18 are formed around the towers and tanks 12 below the position L where gas cutting of the skin 11 is performed (the horizontal cutting line that cuts the steel skin 11 into rounds) and at intervals in the circumferential direction. Form across directions.

This through hole 18 can be formed using a cutting tool (eg, a drill or a drill).
As for the formation position of the above-described through hole 18, below the position L is, for example, a position within the range of 50 mm to 200 mm downward from the position L, preferably a lower limit of 80 mm and an upper limit of 130 mm. Further, the interval in the circumferential direction of the through holes 18 (of the iron shell 11) to be formed is not particularly limited as long as the spacing is such that the spark receiving means 17 does not fall. It is preferable that the pitch be the same throughout, but the pitch may be partially different.

(Roller bracket installation process)
The roller brackets 16 are horizontally projected from the inside of the towers and tanks 12 to the outside of the towers and tanks 12 through the respective through holes 18, and are attached to the respective through holes 18 so as to be radial with respect to the steel shell 11. .
Specifically, as shown in FIG. 1A, first, the base side of the bracket 19 that rotatably supports the rotary roller 20 is lifted diagonally above the through hole 18, and the tip of the locking part 21 of the bracket 19 is lifted. The side is inserted into the through hole 18, and while the bracket 19 is gradually leveled, the locking part 21 is projected to the outside of the tower and tank 12 through the through hole 18, and the bracket 19 is brought into a horizontal state. At this time, by shifting the rotating roller 20 toward the base side of the bracket 19 (to the front side as seen from the operator), the rotating roller 20 becomes an obstacle, and the tip side of the bracket 19 does not enter the through hole 18 with a small diameter. The situation can be avoided.

Next, as shown in FIG. 1(B), the bracket 19 is pushed out of the towers and tanks 12, and the rotating roller 20 is caused to project outside of the towers and tanks 12 through the through holes 18. At this time, the fixing boss 22 is inserted into the through hole 18 until the stopper part 23 provided on the fixing boss 22 comes into contact with the inner surface of the iron skin 11, and the space between the fixing boss 22 and the through hole 18 ( A cotter 24 is driven into the gap), and the fixing boss 22 is attached and fixed to the through hole 18.
Thereby, the roller bracket 16 can be attached to and detached from each through hole 18, so that it can be easily used repeatedly. Note that the orientation of the locking portion 21 of the bracket 19 can be determined by the marks attached to the number lines 26 and the like, as described above.

(Spark catcher installation process)
A plurality of spark receiving means 17 are sequentially placed from the outside of the towers and tanks 12 on the rotating rollers 20 that protrude outward from the towers and tanks 12, and adjacent spark receiving means 17 are connected to each other. It is fed out and arranged along the outer surface of the iron shell 11.
Specifically, external scaffolds 47 are installed in advance at different positions on the outer periphery of the towers and tanks 12 (here, two locations on both sides (180 degrees) in the diametrical direction of the towers and tanks 12) (Fig. 5 reference). This external scaffolding 47 is not installed over the entire outer periphery of the towers and tanks 12 as in the past, but, for example, depending on the scale (diameter, etc.) of the towers and tanks 12 and the area where gas cutting is to be performed. They may be installed at one location or at three or more locations. In addition, when installing external scaffolds at multiple locations, it is preferable to install them at equal intervals (equal angles) in the circumferential direction of the towers and tanks, but they may be at different intervals. Although new external scaffolding can be installed, existing external scaffolding can also be used.

For example, a worker (not shown) on the external scaffold 47 places the two spark receiving means 17 on the rotating roller 20 and attaches them to the side plate portion 32 of one spark receiving gutter 28 and the other spark receiving gutter 28. The side plate portion 33 is connected to the side plate portion 33 by a connecting means. Note that the two spark receiving means 17 may be placed on the rotating roller 20 in a connected state in advance.
Next, after sending out the two connected spark receiving means 17 along the outer surface of the iron skin 11, the spark receiving means 17 located on the upstream side and the spark receiving means newly placed on the rotating roller 20 are removed. 17 are connected by the method described above and sent out along the outer surface of the iron shell 11. Subsequently, the spark receiving means 17 is placed, connected, and sent out in sequence.
As shown in FIGS. 6 and 7, the downstream corner of the spark receiving gutter 28 of the spark receiving means 17 that is sent out first has a notched shape. During feeding, it is possible to prevent the spark receiving trough 28 from getting caught in the locking portion 21 of the bracket 19.

By performing the above-described method on each external scaffold 47, a plurality of spark receiving means 17 can be arranged circumferentially around the iron shell 11, as shown in FIG.
In addition, when sending out the spark receiving means 17, the protruding length of the bracket 19 is made longer than the maximum width of the bottom plate portion 30 of the spark receiving gutter 28 so that the conveyance thereof can be carried out smoothly. Therefore, as shown in FIGS. 1(B) and 6, a gap is generated between the outer surface of the iron skin 11 and the spark receiving means 17. In this manner, when the gas cutting process described below is performed with a gap generated, the generated sparks fall downward through the gap.

Therefore, as shown in FIGS. 1(C) and 7, the spark receiving means 17 is brought into close contact with the outer surface of the iron skin 11.
Specifically, the worker first pulls the wire 26 and draws the base side of the bracket 19 into the tower and tank 12 . As a result, the spark receiving means 17 on the rotating roller 20 is drawn toward the outer surface of the towers and tanks 12 by the locking portion 21 provided on the bracket 19.
Next, by turning the nut member 25 screwed onto the bracket 19 in the tightening direction, the spark receiving means 17 is further drawn toward the outer surface of the towers and tanks 12 by the locking portion 21, and the spark receiving means 17 is disposed on the spark receiving means 17. The sealed member 34 becomes compressed. Thereby, a gap between the outer surface of the iron shell 11 and the spark receiving means 17 can be eliminated.

(Gas cutting process)
Gas cutting is performed from the inside of the towers and tanks 12 to the position L of the steel shell 11, and the generated sparks are received by the spark receiving means 17.
Thereby, sparks generated during gas cutting can be prevented from falling (scattering) downward outside the towers and tanks 12.
Note that the gas cutting is not performed continuously over the entire circumferential direction of the iron skin 11 (not completely cut and separated), but is performed intermittently. For example, it is preferable not to perform gas cutting only on the portion where the external scaffolding 47 is installed.

(Post-process)
After the above-described gas cutting process is completed, the spark scattering prevention device 10 is removed from the iron skin 11.
This is because the operations performed in the roller bracket installation process and the spark receiving means installation process described above are performed in reverse order, so a brief explanation will be given below.
First, an operator inside the towers and tanks 12 turns the nut member 25 screwed onto the bracket 19 in a loosening direction, and pushes the base side of the bracket 19 out of the towers and tanks 12. Thereby, a gap can be formed between the outer surface of the iron skin 11 and the spark receiving means 17, as shown in FIGS. 1(B) and 6.

Subsequently, the worker on each external scaffold 47 sequentially pulls each spark receiving means 17 toward the external scaffold 47 while uncoupling the connecting means provided on the adjacent spark receiving means 17. 17 is lowered from the rotating roller 20. Thereby, the spark receiving means 17 disposed around the circumferential direction of the iron shell 11 can be recovered onto each external scaffold 47, respectively.
After the collection of the spark receiving means 17 is completed, the worker pulls out the cotter 24 from between the fixing boss 22 and the through hole 18, and then pulls the base side of the bracket 19 into the tower tank 12, and as shown in FIG. 1. Remove the roller bracket 16 from the through hole 18 by operating the bracket 19 in the opposite direction to the direction of the arrow in (A).

Then, the uppermost upper and lower scaffold set 43 is lifted up via wires or the like by a heavy machine (not shown) such as a crane and lowered to the ground. Note that the upper and lower scaffolding assembly 43 may be disassembled on the spot in advance and then lowered to the ground using heavy machinery, but by disassembling it after being lowered to the ground, the upper part of the towers and tanks 12 can be disassembled in parallel with this disassembly. The following cutting operations can be performed.
Subsequently, while the cylindrical steel shell part to be separated is suspended by heavy machinery, the part where gas cutting has not been performed is cut off from the outside of the towers and tanks 12 and removed from the other parts. In addition, since the part where gas cutting is not performed is a part where the external scaffolding 47 is installed, gas cutting can be performed from the outside of the towers and tanks 12.

The above-mentioned steps are also carried out sequentially for the second column from the top of the towers and tanks 12 shown in FIG. Removed sequentially from
Note that the separation of the cylindrical steel skin part (cutting off gas from the outside) may be performed before lowering the upper and lower scaffolding assembly 43 to the ground (after separating the cylindrical steel skin part, the upper and lower scaffolding assembly 43 may be separated). 43 may be lowered to the ground).
In addition, the gas cutting of the cylindrical steel skin part is performed continuously (sliced into rings) along the entire circumferential direction of the steel skin 11 while the cylindrical skin part to be cut and removed is suspended by heavy machinery. You can also do it.
In this case, once the gas cutting is complete, the cut steel skin is lowered using heavy machinery and removed. Thereafter, by loosening the nut member 25 screwed onto the bracket 19 and loosening the bolts and nuts connecting the adjacent spark receiving means 17, the spark receiving means 17 and the roller bracket 16 can be easily attached to the scaffold (work floor). 45).

Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the configuration described in the embodiments described above, and the matters described in the claims are as follows. It also includes other embodiments and modifications that may be considered within the scope. For example, it is also within the scope of the present invention to configure a device for preventing spark scattering during gas cutting and a method for dismantling towers and tanks according to the present invention by combining some or all of the embodiments and modifications described above. It will be done.
For example, when dismantling towers and tanks, in the case of tower-like structures such as hot blast furnaces, which are a type of blast furnace equipment, where firebricks are packed inside or pasted on the inside of the walls, the interior After removing the bricks, you may install scaffolding to carry out the work, but when removing the bricks from above, scaffolding may be installed on top of the bricks that are being removed. The top surface of the brick itself can also be used as a scaffold.

In the embodiment described above, when the towers and tanks are dismantled, a case has been described in which a plurality of spark receiving means are continuously installed over substantially the entire outer circumference of the towers and tanks. The area is not particularly limited as long as it is an area where gas cutting is performed; for example, multiple (two or more) spark receiving means may be installed partially (intermittently) only in the area where gas cutting is performed. .
Since the towers and tanks are cylindrical, the steel shell that makes up the outer surface of the towers and tanks is also cylindrical (circular in cross section); The shape is not particularly limited, and may have an elliptical cross-sectional shape, for example, depending on the type of tower or tank.

In the embodiment described above, a case is described in which the roller bracket is attached to a through hole formed in the iron shell using an attachment means having a fixing boss, a stopper part, a cotter, and a nut member. However, the configuration of the attachment means is not particularly limited as long as it can be attached to and detached from the through hole of the roller bracket. Note that the roller bracket can also be attached and fixed to the through hole using, for example, welding, if necessary.
Furthermore, in the embodiment described above, the case where the scattering prevention auxiliary plate section is extended above the spark scattering prevention plate section has been described, but for example, after removing the spark scattering prevention device from the iron shell, If the skin part is removed (if damage to the spark scatter prevention plate can be prevented), it is also possible to construct the spark scatter prevention plate only, including the installation area of the scatter prevention auxiliary plate.

10: Spark scatter prevention device during gas cutting, 11: Steel shell, 12: Towers and tanks, 16: Roller bracket, 17: Spark receiving means, 18: Through hole, 19: Bracket, 20: Rotating roller, 21: Connection stop part, 22: fixing boss, 23: stopper part, 24: cotter, 25: nut member, 26: wire, 27: ball bearing, 28: spark catch gutter, 29: spark scattering prevention plate part, 30: bottom plate part , 31: Base plate part, 32, 33: Side plate part, 34: Seal member, 35: Scattering prevention auxiliary plate part, 36: Connection hole, 40: Scaffold, 41: Upper scaffold, 42: Lower scaffold, 43: Upper and lower Scaffolding group, 44: Scaffolding framework, 45: Working floor, 46: Lifting stairs, 47: External scaffolding

Claims (12)

A spark scattering prevention device used when performing gas cutting of the steel shell from the inside of a cylindrical tower tank equipped with the steel shell, comprising:
The tower is attached to a plurality of through holes formed in the steel shell at intervals in the circumferential direction below the position of the steel shell where the gas cutting is performed, and is installed from inside the tower tank. a plurality of brackets that are arranged to protrude horizontally to the outside of the tanks and rotatably support rotating rollers;
A plurality of spark receiving means are sent out along the outer surface of the iron skin by the rotating roller and are connectable to each other in the feeding direction to receive sparks generated when the gas cutting of the iron skin is performed. Features a spark scatter prevention device during gas cutting. 2. The device for preventing sparks from scattering during gas cutting according to claim 1, wherein the rotary roller is movable in the axial direction of the bracket, and a locking portion is provided at a tip of the bracket, and a locking portion is provided at a tip of the bracket, and a locking portion is provided at a tip of the bracket. By pulling the attached base side of the bracket into the inside of the tower tank, the spark receiving means on the rotating roller is drawn to the outer surface of the steel shell at the locking portion. Device to prevent sparks from scattering when cutting. 3. The spark scattering prevention device during gas cutting according to claim 2, wherein the spark receiving means includes a spark receiving gutter serving as a bottom portion, and is provided on the tip side of the spark receiving gutter and is inclined toward the outer surface of the iron skin. What is claimed is: 1. A device for preventing sparks scattering during gas cutting, comprising a sparks scattering prevention plate portion arranged therein. 4. The spark scattering prevention device during gas cutting according to claim 3, wherein an auxiliary scattering prevention plate section made of an elastic body extends above the spark scattering prevention plate section. Time spark scatter prevention device. In the device for preventing scattering of sparks during gas cutting according to any one of claims 2 to 4, it is preferable that a sealing member is provided on a surface of the spark receiving means facing the outer surface of the iron shell. Features a spark scatter prevention device during gas cutting. 6. The apparatus for preventing scattering of sparks during gas cutting according to any one of claims 1 to 5, wherein the bracket is attachable to and detachable from the through hole. . A method for dismantling cylindrical towers and tanks including gas cutting of the steel skin from the inside of the tower and tanks, the method comprising:
a preparatory step of forming a plurality of through holes in the steel shell from inside the tower tank, below the position of the steel shell where the gas cutting is performed, and having intervals in the circumferential direction;
a roller bracket installation step of attaching a bracket that rotatably supports a rotary roller to each of the through holes from inside the towers and tanks so as to protrude horizontally to the outside of the towers and tanks;
A plurality of spark receiving means are sequentially placed from outside the towers and tanks on the rotating roller that protrudes outward from the towers and tanks, and adjacent spark receiving means are connected to each other, and the rotating roller a step of installing a spark receiving means to send out and arrange it along the outer surface of the iron skin;
A method for dismantling towers and tanks, comprising the step of performing the gas cutting on the steel shell from inside the tower and tanks, and receiving sparks generated by the spark receiving means. 8. The method for dismantling towers and tanks according to claim 7, in the step of installing the spark receiving means, the base side of the bracket attached to the through hole is pulled into the inside of the towers and tanks, and the spark receiving means is installed at the tip of the bracket. A tower tank characterized in that the spark receiving means on the rotary roller is drawn to the outer surface of the steel shell by the locking portion, and a gap between the outer surface of the steel shell and the spark receiving means is eliminated. How to disassemble. 9. The method for dismantling towers and tanks according to claim 8, wherein the spark receiving means is provided at a spark receiving gutter serving as a bottom portion and at a tip side of the spark receiving gutter, and is inclined toward an outer surface of the iron shell. A method for dismantling towers and tanks, characterized by having a spark scattering prevention plate part. 10. The method for dismantling towers and tanks according to claim 9, wherein an auxiliary scattering prevention plate made of an elastic body is extended above the spark scattering prevention plate. Disassembly method. The method for dismantling towers and tanks according to any one of claims 8 to 10, characterized in that a sealing member is provided on a surface of the spark receiving means facing the outer surface of the iron shell. How to dismantle towers and tanks. 12. The method for dismantling towers and tanks according to any one of claims 7 to 11, characterized in that the bracket can be attached to and removed from the through hole.

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