WO2019022312A1

WO2019022312A1 - Device for processing object to be processed and method for repairing same

Info

Publication number: WO2019022312A1
Application number: PCT/KR2017/014400
Authority: WO
Inventors: 박상현; 김정일; 이형정; 남용호; 최태화
Original assignee: 주식회사 포스코
Priority date: 2017-07-24
Filing date: 2017-12-08
Publication date: 2019-01-31
Also published as: KR20190011036A

Abstract

The present invention relates to a device for processing an object to be processed. The device processes the object to be processed at a temperature higher than that of the outside. The device comprises: an outer shell that forms an inner space in which the object to be processed can be processed; and an inner shell installed inside the outer shell. At least parts of the outer shell and the inner shell have a plurality of blocks connected to each other in a separable manner. Accordingly, a damaged part can be easily replaced or repaired.

Description

Apparatus for treating object to be treated and method for repairing the same

The present invention relates to an object to be treated and a method for repairing the object, and more particularly, to an object to be treated and a method for repairing the object, which can easily replace or repair a damaged part.

Generally, blast furnace operation is a process of charging iron ore and coke to the upper part of a blast furnace, a process of burning coke by blowing hot wind with a tug formed in the blast furnace, a process of removing impurities and oxygen of iron ores by the heat and gas generated by burning coke, . &Lt; / RTI > The molten iron in the liquid state is stored in the lower part of the blast furnace, and is discharged through the outlet after a lapse of a predetermined time.

A stave is installed on the inner side of the iron pipe forming the outer shape of the blast furnace. The stave is formed with a path through which the cooling water moves within the stator in order to protect the scraps from the heat generated in the blast furnace. Therefore, it is possible to prevent the cooling water, which moves inside the stave, from cooling the wick to be thermally deformed.

As the use time of the blast furnace increases, the stab may wear due to the thermal load or the friction due to the falling of the charge in the blast furnace. Conventionally, when the stave is damaged, the stitch is cut from the outside to replace the stave inside the stitch.

However, in order to replace damaged stoves, it is necessary to cut the inner insulation and refractory as well as the iron. In addition, in order to secure a replacement work space, it is necessary to cut the scrim in the area corresponding to the damaged stave to the scrim of the surrounding area. Therefore, there is a problem that a lot of time is required to replace the stave.

[Prior Art Literature]

(Patent Document 1) Korean Patent Laid-Open Publication No. 2014-0011143

The present invention provides an object to be treated and a method of repairing the object, which can easily replace or repair a damaged part.

The present invention provides an object-to-be-treated apparatus and a method of repairing the object, which are easy to maintain.

The present invention relates to an apparatus for treating a material to be treated at a temperature higher than the outside, comprising: a casing forming an inner space through which a material to be treated can be processed; And an inner skin disposed inside the outer shell,

And at least a part of the outer skin and the inner skin are detachably connected to each other.

The block comprising: a first plate defining a portion of the shell; And a second plate formed along the shape of the first plate and coupled with the first plate to form a part of the inner plate.

The second plate includes: a heat insulating member connected to the first plate; A cooling member whose one surface is connected to the heat insulating member; And a refractory member connected to the other surface of the cooling member.

A plurality of grooves are formed on the other surface of the cooling member, and the refractory member includes a plurality of fireproof plates, and protrusions connected to the fireproof plate and capable of being fitted and defected in the grooves.

The protrusion and the insertion portion are formed in the block, and the protrusion of another block may be inserted into the insertion portion of one block.

The object to be treated includes iron ore, and the object to be treated includes a blast furnace equipped with an outlet.

And the plurality of blocks are disposed in an area adjacent to the exit port.

The blast furnace includes a shaft portion having a width widened from an upper side to a lower side, a valley portion connected to a lower portion of the shaft portion, a bosh portion connected to a lower portion of the valley portion, And the plurality of blocks are disposed in at least one of the shaft portion, the valley portion, the boshe portion, and the furnace body portion.

The present invention relates to a method for repairing an object to be treated that treats a material to be treated at a higher temperature than the outside, comprising: a plurality of blocks each of which is detachably connected to at least a part of an outer skin and an inner skin, Process; Separating the damaged block from the plurality of blocks; And installing a non-damaged block on the separated portion of the damaged block.

The blocks are formed in different shapes according to their height,

The step of installing the non-damaged block may include: selecting a new block having a shape corresponding to the shape of the damaged block; And inserting a new block selected at a portion where the block is separated in the object to be processed.

The step of installing the non-damaged block may include: repairing the damaged part in the damaged block; And inserting the repaired block into a portion of the object to be processed that is separated from the block.

The process of arranging the plurality of blocks may include disposing a plurality of blocks in an area where damage is more likely to occur than in another area in the object to be processed.

According to the embodiments of the present invention, a damaged portion of the object to be treated can be easily repaired. And a block in which at least a part of the object to be processed is detachably connected. Thus, when a damage occurs to the object to be treated, only the damaged block can be separated from other blocks and replaced with an unimpaired block. Therefore, the damaged part of the object to be treated can be quickly and easily repaired or replaced, and maintenance of the facility can be facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing an object to be processed according to an embodiment of the present invention. Fig.

2 is a view showing an apparatus for treating an object according to another embodiment of the present invention.

3 is a view showing a connection structure of a cooling member and a refractory member according to an embodiment of the present invention.

4 is a diagram illustrating a structure in which blocks according to an embodiment of the present invention are connected.

5 is a flowchart showing a method of repairing an object to be treated according to an embodiment of the present invention.

6 is a diagram illustrating a procedure for replacing a damaged block according to an embodiment of the present invention;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. To illustrate the invention in detail, the drawings may be exaggerated and the same reference numbers refer to the same elements in the figures.

FIG. 1 is a view showing a device for treating a material according to an embodiment of the present invention, FIG. 2 is a view showing a device for treating a material according to another embodiment of the present invention, and FIG. Fig. 7 is a view showing a connection structure of a cooling member and a refractory member according to the present invention;

Referring to FIGS. 1 and 2, an object to be processed 1000 according to an embodiment of the present invention is a device for processing a material to be processed at a higher temperature than the outside, 200). At this time, the object to be treated 1000 may be a blast furnace, and the object to be treated may include iron ores. Accordingly, the object to be treated 1000 may further include a tuyere (not shown), a hot air supply line (not shown), and an outlet 300.

The tuyere may be provided below the object to be treated 1000. A plurality of tuyeres may be disposed along the periphery of the object to be treated 1000. The tuyere can be connected to the hot air supply line. Accordingly, the hot air supplied from the hot air supply line can be supplied into the object to be treated 1000 through the tuyere. Therefore, the iron ore charged into the object to be treated 1000 together with the coke may be dissolved to produce molten iron.

The exit port 300 may be provided at a lower portion of the object to be treated 1000. The exit port 300 may be located below the tuyere. The outlet 300 serves to discharge the charcoal inside the object to be treated 1000. The plurality of outgoing ports 300 may be disposed along the periphery of the object to be treated 1000.

Further, the exit port 300 can be opened and closed. Thus, when the outflow port 300 is closed, the molten iron can be maintained in the inside of the object to be treated 1000, and when the outflow port 300 is opened, .

The object to be treated 1000 may be divided into a furnace body portion and a furnace bottom portion. The furnace body and the furnace bottom can be classified based on the position of the outlet 300. That is, the upper side of the exit port 300 may be a hollow body, and the lower side of the exit port 300 may be a nosepiece. At this time, stresses may be intensively generated in the vicinity of the exit port 300 and the furnace bottom. Accordingly, there arises a problem that the portion of the object to be treated 1000 that is located at the exit port 300 and the furnace portion is easily worn or damaged.

The envelope 100 forms an internal space through which the object to be processed can be processed. The envelope 100 is formed in a container shape, and the upper part is opened to form the outer shape of the object to be processed 1000. Thus, the object to be processed can be charged into the inner space through the open top. Further, the envelope 100 may be an iron plate. However, the shape and material of the envelope 100 are not limited thereto and may vary.

The inner skin (200) is installed inside the outer skin (100). The inner skin 200 protects the outer skin 100 from the heat generated while processing the object.

At this time, at least a part of the outer skin 100 and the inner skin 200 may have a plurality of blocks detachably connected to each other. That is, the entire outer skin 100 and the inner skin 200 may be composed of blocks, and only a part of the outer skin 100 and the inner skin 200 may be blocks.

When the entire outer skin 100 and the inner skin 200 are formed of blocks as shown in FIG. 1, the blocks may be constructed as bricks. That is, the blocks may be arranged along the circumferential shape of the object to be processed 1000 in the width direction to form one layer, and a plurality of layers may be formed in the vertical direction. Thus, the blocks can form both the outer shape of the object to be processed 1000 and the inner space. Therefore, even if any part of the object to be treated 1000 is damaged, only the damaged part can be removed and replaced.

Further, the blocks may be staggered in the vertical direction. Therefore, when any one of the blocks is separated, it is possible to prevent the other blocks from collapsing.

As shown in FIG. 2, when only a part of the outer skin 100 and the inner skin 200 are composed of blocks, the blocks can be arranged in a region where thermal damage is more likely to occur than other regions. That is, the blocks can be disposed in the area adjacent to the exit port 300 where the ablation or scratches easily occur in the object to be treated 1000 or in the exposure area.

For example, one layer on the upper side of the exit port 300 and one layer on the lower side of the exit 300 may be formed as blocks adjacent to the exit 300. Therefore, if any one of the blocks disposed on the upper layer of the exit 300 and the lower layer of the exit 300 is damaged, only the damaged block can be detached and replaced.

Alternatively, if any one of the blocks disposed in the furnace of the object to be treated 1000 is damaged, only the damaged block can be detached and replaced. Therefore, since the area where the damage easily occurs is made of a block, maintenance can be facilitated by replacing only a damaged block. When only a part of the object to be processed 1000 is formed into a block, manufacturing time and cost can be reduced as compared with the case where the whole object is formed into a block.

On the other hand, the body portion of the object to be processed 1000 has a shaft portion having a larger width from the upper side to a lower side, a valley portion connected to the lower portion of the shaft portion, Bosch department. The upper part of the valley part is connected to the lower part having the widest width in the shaft part and the lower part of the valley part is connected to the upper part having the widest width in the bosch part.

At this time, in the shaft portion, the valley portion, and the boss portion, abrasion or damage of the refractory member occurs less than in the furnace portion, but an accident may occur that the cooling fluid line installed on the cooling member easily pops up. Therefore, in order to facilitate the replacement of the cooling member on which the cooling fluid line is installed, a plurality of blocks can be disposed in at least one of the shaft portion, the boss portion, and the valley portion. Therefore, only the block of the damaged portion of the cooling fluid line can be separated and replaced easily.

The block includes a first plate (110), and a second plate (210). At this time, the blocks may be formed to have different shapes depending on the height (or layer) to be disposed. That is, since a part of the object to be processed 1000 is formed to be convex, the blocks may be formed in different shapes according to their positions. However, the present invention is not limited thereto, and the blocks may be formed in the same shape according to the shape of the object to be processed 1000.

The first plate (110) forms a portion of the envelope (100). The first plate 110 may have a rectangular plate shape. The first plate 110 has an area in the longitudinal direction and a width direction, and may have a thickness in the thickness direction. However, the shape of the first plate 110 is not limited to this, and may vary.

The second plate 210 forms a part of the inner skin 200. The second plate 210 may be formed along the area and shape of the first plate. That is, the second plate 210 may have the same area and shape as the first plate 110. Accordingly, the second plate 210 may be formed in a rectangular plate shape. The second plate 210 has an area in the longitudinal direction and a width direction, and may have a thickness in the thickness direction. However, the shape of the second plate 110 is not limited to this and may vary.

Also, the second plate 210 is coupled to the first plate 110 inside the envelope 100. Accordingly, the second plate 210 protects the first plate 110 from heat generated when the object to be processed is processed.

The second plate 210 includes a heat insulating member 212 connected to the first plate 110, a cooling member 213 having one side connected to the heat insulating member 212 and a cooling member 213 connected to the other side of the cooling member 213 And includes a refractory member 211.

The heat insulating member 212 may be formed in a rectangular plate shape along the shape of the first plate 110. Thus, the heat insulating member 212 may form one block together with the cooling member 213, the refractory member 211, and the first plate 110.

Further, the heat insulating member 212 may be made of castable (or atypical refractory). The heat insulating member (212) can be engaged with one surface of the first plate (110). Therefore, the heat insulating member 212 can suppress or prevent the heat generated in the object to be treated 1000 from being transferred to the first plate 110. Therefore, it is possible to prevent the first plate 110 from being deformed by heat. However, the material of the heat insulating member 212 is not limited thereto and may vary.

The cooling member 213 may be formed in a rectangular plate shape along the shape of the first plate 110. The cooling member 213 may be positioned between the heat insulating member 212 and the refractory member 211. Therefore, the cooling member 213 can form one block together with the heat insulating member 212, the refractory member 211, and the first plate 110. At this time, the cooling member 213 may be a stave.

One side of the cooling member 213 is coupled to the heat insulating member 212 and a plurality of grooves 213a may be formed on the other side of the cooling member 213 as shown in FIG. The groove 213a may be formed by being cut from the other surface of the cooling member 213 toward one surface of the cooling member 213. [ However, the shape and structure of the cooling member 213 are not limited to this and may be various.

The refractory member 211 may be formed in a rectangular plate shape along the shape of the first plate 110. Thus, the refractory member 211 may form one block together with the cooling member 213, the heat insulating member 212, and the first plate 110.

The refractory member 211 may be a refractory provided on the other surface of the cooling member 213. Therefore, the refractory member 211 can protect the cooling member 213 from the heat generated in the inside of the object to be treated 1000 and the charge. Therefore, the refractory member 211 can be worn or damaged by heat and charge over time, and at least a part of the cooling member 213 is damaged by the damaged refractory member 211, It may be exposed to the inner space.

3, the refractory member 211 has a plurality of fireproofing plates and a protrusion 211a connected to the fireproof plate and detachably fitted in the groove 213a formed in the cooling member 213 . Thus, if any one of the plurality of fireproof plates coupled to the cooling member 213 is damaged, only the damaged fireproof plate can be separated from the cooling member 213 and replaced. Therefore, only a part of the refractory member 211 is replaced without replacing the entire refractory member 211, so maintenance can be facilitated.

At this time, the cooling member 213 may be connected to the cooling fluid line 215. The cooling fluid line 215 forms a path through which the cooling fluid travels. The cooling fluid line 215 may comprise a moving tube, a feed tube, and a drain tube.

The moving pipe may extend in the vertical direction and may be inserted into the cooling member 213. The supply pipe may be connected to one end of the moving pipe through the other surface of the first plate 110, the heat insulating member 212, and the cooling member 213. The discharge pipe may be connected to the other end of the moving pipe through the other surface of the first plate 110, the heat insulating member 212, and the cooling member 213. Thus, the cooling fluid supplied to the moving pipe through the supply pipe can be discharged to the discharge pipe. Therefore, the cooling member 213 can cool the refractory member 211 and the first plate 110 through the cooling fluid moving inside.

At this time, a valve is provided in the supply pipe to adjust the amount of the cooling fluid supplied to the pipe. The cooling fluid may be cooling water. However, the type of cooling fluid is not limited to this and may vary. Further, the structure and shape of the refractory member 211, the heat insulating member 212, and the cooling member 213 are not limited to these, and may vary.

4 is a diagram illustrating a structure in which blocks according to an embodiment of the present invention are connected. Hereinafter, a structure in which a plurality of blocks according to an embodiment of the present invention are connected to each other will be described.

Referring to FIG. 4 (a), the block may be formed into a hexagonal brick shape. Thus, blocks can be constructed like bricks. Accordingly, the blocks can be formed along the peripheral shape of the object to be treated 1000 to form at least a part of the outer shape and the inner space of the object to be processed 1000. The blocks may be disposed in close contact with each other so as not to generate a gap. Thus, the blocks can seal the internal space of the object to be processed 1000. [

On the other hand, as shown in FIGS. 4B and 4C, the protrusion A and the insertion portion B may be formed in the block. Thus, the protruding portion A of another block can be inserted into the insertion portion B of any one block. The protruding portion A and the inserting portion B may be provided in one block, or a plurality of protruding portions A and B may be provided in the same number.

For example, as shown in FIG. 4 (b), protruding portions A projecting outwardly may be formed on upper or lower portions of both sides of a block body formed in a brick shape. The insertion portion B may be formed on both sides and the upper portion or the upper portion of the block body inwardly (or protruding portion A is protruded). The protruding portion A of another block can be inserted into the one insertion portion B of one block and the protruding portion A of another block can be inserted into the other insertion portion B of any one block.

Alternatively, as shown in FIG. 4C, a protruding portion A protruding outwardly may be formed only on one side of the block body formed in a brick shape. The protruding portion A may be formed at one side lower portion of the block body. And an inserting portion B which is inwardly drawn only on the other side opposite to one side of the block body can be formed. The insertion portion B may be formed on the other side of the block body. Therefore, the protruding portion A of another block can be fitted to the insertion portion B formed in one block.

Alternatively, the protrusion A may be formed at the center of the front surface of the block body, and the insertion portion B may be formed at the center of the rear surface of the block body. Therefore, the protruding portion A of another block is inserted into the insertion portion B formed in one block, so that the blocks can be combined.

At this time, the insertion portion B may be formed along the shape of the protrusion A so that the protrusion A can be inserted into the insertion portion B. For example, the projection A may be formed in a hexahedral shape, and the insertion portion B may be formed in a shape corresponding thereto. Thus, the blocks can be easily fitted to each other and constructed. Therefore, the blocks can be easily positioned in place, and the coupling force between the blocks can be improved. However, the structure, shape, and number of the projections A and B provided in the block are not limited to this, and may vary.

As such, the object to be processed 1000 may include a block to which at least a part of the object to be processed 1000 is detachably connected. Thus, when the object to be treated 1000 is damaged, only the damaged block can be separated from the other blocks and replaced with an uncorrupted block. Therefore, the damaged part of the object to be treated 1000 can be quickly or easily repaired or replaced, and maintenance of the facility can be facilitated.

FIG. 5 is a flowchart showing a method for repairing an object to be treated according to an embodiment of the present invention, and FIG. 6 is a diagram showing a procedure for replacing a damaged block according to an embodiment of the present invention. Hereinafter, a method of repairing an object to be treated according to an embodiment of the present invention will be described.

5, a method for repairing an object to be treated according to an embodiment of the present invention is a method for repairing an object to be treated that treats the object to be treated at a higher temperature than the outside, (S110) of preparing a to-be-processed object including a plurality of blocks detachably connected to each other (S110), separating a damaged block from a plurality of blocks (S120) And installing a non-damaged block (S130). At this time, the object to be treated 1000 may be a blast furnace, and the object to be treated may include iron ores.

Referring to FIGS. 1 to 4, when the entire outer skin 100 and the inner skin 200 are composed of blocks, the object to be processed 1000 can be provided by building blocks like bricks. That is, the blocks may be arranged along the circumferential shape of the object to be processed 1000 in the width direction to form one layer, and a plurality of layers may be formed in the vertical direction. Thus, the blocks can form both the outer shape of the object to be processed 1000 and the inner space.

When only a part of the outer covering 100 and the inner covering 200 are formed of blocks, the blocks can be arranged in a region where heat damage is more likely to occur than other regions. That is, the blocks can be disposed in the area adjacent to the exit port 300 where the ablation or scratches easily occur in the object to be treated 1000 or in the exposure area.

When a damaged portion is found in the object to be treated 1000, it is possible to perform an operation of separating the damaged portion from other blocks of the block. Since the refractory member 211 of the second plate 210 provided in the block is in direct contact with the molten metal, it may be worn by the heat and the charged material as time goes by or may be damaged as shown in FIG. 6 (a). Accordingly, an accident that at least a part of the cooling member 213 provided in the block is exposed to the internal space of the object to be treated 1000 may occur.

When the refractory member 211 is found to have a damaged block, the block in which the damaged portion is found can be extracted and separated from the other blocks. For example, only a block in which a damaged part is found can be pushed out to the outside of the object to be processed 1000 by using a separate apparatus, as shown in FIG. 6 (b).

Then, the undamaged block can be inserted into the separated portion of the damaged block as shown in FIG. 6 (c). For example, you can insert a new block. New blocks can be prepared in advance, and one of the prepared blocks can be selected so that the damaged block can be inserted into the separated part.

At this time, the blocks may be formed to have different shapes depending on the height (or layer) to be disposed. That is, when the object to be processed 1000 is in a blast furnace, the blocks are formed in a convex shape, so that the blocks may be formed in different shapes according to their positions. Therefore, when preparing new blocks in advance, it is possible to prepare blocks of a shape corresponding to (or the same) shape as the shape of a block that fits at each height. It is possible to perform a repair work by selecting a block that corresponds to a portion where the damaged block is separated from the prepared blocks (or corresponds to a damaged block shape).

On the other hand, the damaged block may be separated from the other blocks, the damaged block may be repaired, and the repaired block may be re-inserted. That is, the damaged block is extracted from other blocks and separated. Damage can be repaired in a separate block.

For example, if any one of the plurality of fireproof plates coupled to the cooling member 213 provided in the block is damaged, only the damaged fireproof plate can be separated from the cooling member 213 and replaced with a new fireproof plate. Therefore, only the damaged part can be replaced and replaced without replacing the entire refractory member 211.

Then, the repaired block can be reinserted to the part where the block is separated in the object to be processed 1000. [ Therefore, the damaged portion of the object to be treated 1000 can be easily repaired as shown in FIG. 6 (d).

Particularly, in the case where the object to be treated 1000 includes the outer skin 100 and the inner skin 200, when the inner skin 200 is damaged, only the corresponding block can be separated and repaired. Therefore, in order to secure the replacement work space for the inner skin 200, it is not necessary to cut the outer skin 100 of the area corresponding to the damaged inner skin 200 and the peripheral area thereof, so that the maintenance work can be facilitated.

Although the present invention has been described in detail with reference to the specific embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be defined by the appended claims, as well as the appended claims.

Claims

1. An object to be treated which processes a material to be treated at a higher temperature than the outside,

A shell forming an inner space through which the material to be treated can be processed; And

And an inner skin disposed inside the outer shell,

And at least a part of the outer skin and the inner skin are detachably connected to each other.
The method according to claim 1,

The block includes:

A first plate forming a portion of the shell; And

And a second plate formed along the shape of the first plate and coupled with the first plate to form a part of the endothelium.
The method of claim 2,

Wherein the second plate

A heat insulating member connected to the first plate;

A cooling member whose one surface is connected to the heat insulating member; And

And a refractory member connected to the other surface of the cooling member.
The method of claim 3,

A plurality of grooves are formed on the other surface of the cooling member,

Wherein the refractory member includes a plurality of fireproofing plates and protrusions connected to the fireproofing plate and capable of being fitted and defective in the grooves.
The method of claim 3,

A protrusion and an insertion portion are formed in the block,

And a protruding portion of another block can be inserted into an insertion portion of one block.
The method according to any one of claims 1 to 5,

Wherein the object to be treated includes iron ore, and the object to be treated has an exit port.
The method of claim 6,

Wherein the plurality of blocks are disposed in an area adjacent to the exit port.
The method of claim 6,

The blast furnace includes a shaft portion having a width widened from an upper side to a lower side, a valley portion connected to a lower portion of the shaft portion, a bosh portion connected to a lower portion of the valley portion, And the like,

Wherein the plurality of blocks are disposed in at least one of the shaft portion, the valley portion, the boshe portion, and the furnace body portion.
A method for repairing an object to be treated which processes the object to be treated at a higher temperature than the outside,

A process for preparing an object to be processed having a plurality of blocks in which at least a part of an outer skin and an inner skin are detachably connected to each other;

Separating the damaged block from the plurality of blocks; And

And installing a non-damaged block on a portion where the damaged block is separated.
The method of claim 9,

The blocks are formed in different shapes according to their height,

Wherein the step of installing the non-

Selecting a new block having a shape corresponding to the shape of the damaged block; And

And inserting a new block selected at a portion where the block is separated in the object-to-be-processed apparatus.
The method of claim 9,

Wherein the step of installing the non-

Repairing the damaged part in the damaged block; And

And inserting the repaired block into a portion where the block is separated in the object to be processed.
The method according to any one of claims 9 to 11,

Wherein the step of providing the plurality of blocks comprises:

And arranging a plurality of blocks in an area where damage is more likely to occur than in another area in the object to be treated.