JP7202163B2 - Insulation structure for covering water-cooled pipes, division block used therein, and construction method and repair method for the insulation structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cylindrical heat insulating structure covering water cooling pipes used in a heating furnace, a blast furnace, a heat treatment furnace, etc., a split block used therein, and a method for constructing and repairing the heat insulating structure.

In order to prevent the insulating material from coming off or sticking out, the tubular heat insulating material applied to the water cooling pipe of a heating furnace or the like is often supported by a stud welded to the water cooling pipe.

On the other hand, the heat insulating material may be partially worn, and a support structure that allows partial repair is desired. However, if the heat insulating material is supported by studs, the studs must be dismantled when dismantling the worn part, and the studs must be welded to the pipe again when repairing, resulting in poor work efficiency. rice field.

In addition, studs have a large heat loss, and thousands of studs need to be welded in the entire furnace.

As a support structure that does not use studs, for example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-127619), two or more refractory blocks are combined to form a ring, and these are stacked in a cylindrical shape to form a water cooling pipe. In a covering heat insulation structure, the refractory blocks are radially inclined with respect to a plane normal to the stacking direction, and the joint positions of the circumferential dividing surfaces are alternately shifted one step at a time. Disclosed is a heat insulating structure covering a water-cooled pipe characterized by:

Patent Document 2 (Japanese Patent Application Laid-Open No. 2013-112832) discloses a heat insulating structure covering a water-cooled pipe formed into a ring shape by combining three or more divided blocks, and the ring-shaped block portion is arranged in the longitudinal direction of the water-cooled pipe (usually A heat insulating structure is disclosed in which a plurality of blocks are stacked to form a cylindrical block portion while ensuring an expansion allowance in the height direction.

Patent Document 3 (Japanese Patent Application Laid-Open No. 2016-104899) discloses an integrated split block module formed by casting a castable on a metal plate to which ceramic studs are joined in advance, and dividing the module by welding the metal plate to a water cooling pipe. A construction method for joining block modules is disclosed.

JP 2012-127619 A Japanese Patent Application Laid-Open No. 2013-112832 Japanese Patent Application Laid-Open No. 2016-104899

However, with the conventional structures described in Patent Documents 1 to 3, when performing partial repairs, it was not easy to dismantle only the target worn parts or pull out only the worn blocks for repair or replacement.

In Patent Document 1, since the divided blocks are inclined with respect to the radial direction, it is possible to exert a restraining force in the radial direction, but it is difficult to pull out only the worn divided blocks. There is a risk of collapse because there is no means of support.

Even in the structure of Patent Document 2, there is a risk of collapsing because there is no means for longitudinally supporting the worn divided block after it is pulled out. In the second embodiment, a tensioning jig is used, but it is described that fixing by welding or the like is necessary. Due to the need for longitudinal clearance, it is necessary to dismantle even the excess dividing blocks.

Patent Document 3 has support in the radial direction and the longitudinal direction, but it is necessary to weld the metal plate during construction or partial repair, and furthermore, it is necessary to remove the welded metal plate by breaking the block during dismantling. Therefore, there was a problem that it was time-consuming.

In other words, in the cylindrical heat insulating structure that covers the water cooling pipe, it is necessary to support the heat insulating material in the radial direction by means of studs, etc., in order to prevent the heat insulating material from protruding or falling off. Furthermore, in the case of partial repair, if there is support in the radial direction, it is difficult to dismantle the damaged portion. In addition, there is a risk that the structure will collapse when the worn parts are dismantled without longitudinal support means. There has never been a structure that solves these problems at the same time.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a heat insulating structure that facilitates construction and partial repair and prevents insulation materials from coming off or protruding, split blocks used therein, and a method for constructing and repairing the heat insulating structure. That is.

As a result of intensive research in view of the above object, the present inventors have detachably provided fixtures for supporting the heat insulating material (divided blocks and support structure) in the radial direction and supported the divided blocks in the longitudinal direction. By providing a support structure with a monolithic refractory for this purpose, it is possible to prevent the insulation material and divided blocks from falling off or protruding during operation, and during partial repair, by removing the fixtures for the radial direction of the damaged divided blocks. The inventors have found that it is possible to remove the only, and arrived at the present invention.

That is, the heat insulation structure covering the water cooling pipe of the present invention includes a plurality of annular blocks that are connected in the axial direction so as to surround the water cooling pipe,
A heat insulating structure covering a water cooling pipe, comprising a support structure formed by hardening a monolithic refractory filled between the plurality of annular blocks and the water cooling pipe, wherein the annular block is annular Composed of two or more combined divided blocks and a fixture that is detachably attached to the outer peripheral side of the divided blocks and fixes the divided blocks to each other ,
The dividing block has an uneven structure on its inner peripheral surface to be supported by the monolithic refractory, and is separable from the supporting structure .

In the heat insulating structure of the present invention, the split blocks have a structure on the outer peripheral surface for the split blocks to be annularly combined and fixed by the fixture, and the fixture is attached to the structure. is preferred.

In the heat insulating structure of the present invention, the monolithic refractory is preferably monolithic refractory castable or refractory powder.

The construction method of the heat insulating structure covering the water cooling pipe of the present invention includes:
forming an annular block by annularly combining the divided blocks by detachably attaching a fixture to the outer peripheral side of two or more divided blocks;
A step of axially connecting and installing a plurality of the annular blocks so as to surround a water cooling pipe;
filling and hardening a monolithic refractory between the plurality of annular blocks and the water cooling pipe to form a support structure made of the monolithic refractory;
The dividing block has an uneven structure on its inner peripheral surface to be supported by the monolithic refractory, and is separable from the supporting structure .

In the construction method of the present invention, it is preferable that the divided blocks have a structure on the outer peripheral surface for the divided blocks to be annularly combined and fixed by the fixture, and the fixture is attached to the structure. .

In the construction method of the present invention, the monolithic refractory is preferably monolithic refractory castable or refractory powder.

The repair method of the present invention is a method of repairing the heat insulating structure of the present invention or the heat insulating structure constructed by the construction method of the present invention,
a step of removing the fixtures that fix the divided block to be repaired, and pulling out or dismantling the divided block to remove it;
replacing the removed divided block, inserting a new divided block, and combining and fixing them in a ring with a fixture to form an annular block.

The split block of the present invention is a split block used in the heat insulating structure of the present invention, the construction method of the present invention, or the repair method of the present invention,
It is characterized by having a structure for annularly combining and fixing the divided blocks by the fixture, and an uneven structure for being supported by the monolithic refractory on the inner peripheral surface.

The heat insulating structure covering the water cooling pipe of the present invention is constructed by installing the annularly combined divided blocks in a cylindrical shape and then pouring and filling the monolithic refractory, without using studs and welding. Since it is not necessary, construction is simplified and heat loss can be reduced. In addition, when performing partial repair, it is only necessary to replace worn divided blocks, so the repair time can be shortened and the amount of dismantling can be reduced.

It is a schematic diagram which shows an example of the annular block which consists of a division block and a fixture. FIG. 10 is a schematic diagram showing another example of an annular block made up of divided blocks and fixtures; FIG. 10 is a schematic diagram showing still another example of an annular block made up of divided blocks and fixtures; FIG. 10 is a schematic diagram showing still another example of an annular block made up of divided blocks and fixtures; It is a schematic diagram which shows an example of the division block in which the chamfered part was provided in the internal peripheral surface. FIG. 10 is a schematic diagram showing an example of a divided block having protrusions on its inner peripheral surface; FIG. 4 is a schematic diagram showing a plurality of annular blocks that are axially connected and installed so as to surround a water-cooled pipe; FIG. 4 is a schematic diagram showing a state in which a monolithic refractory is filled between a plurality of annular blocks and water cooling pipes; FIG. 3 is a schematic diagram showing an example of a support structure in the longitudinal direction obtained by curing the filled monolithic refractory. FIG. 4 is a schematic diagram showing another example of a support structure in the longitudinal direction obtained by curing the filled monolithic refractory. FIG. 5 is a schematic diagram showing still another example of a support structure for the longitudinal direction obtained by curing the filled monolithic refractory. It is a schematic diagram which shows the heat insulation structure for a test produced in the Example. It is a schematic cross section which shows the electric furnace for a test used for the evaluation test of a heat insulation structure.

[1] Thermal insulation structure for covering a water-cooled pipe The insulation structure for covering a water-cooled pipe according to the present invention comprises a plurality of annular blocks that are connected in the axial direction so as to surround the periphery of the water-cooled pipe;
A heat insulating structure covering a water cooling pipe, comprising a support structure formed by hardening a monolithic refractory filled between the plurality of annular blocks and the water cooling pipe, wherein the annular block is annular Composed of two or more combined divided blocks and a removable fixture for fixing the adjacent divided blocks,
The dividing block is characterized by having an uneven structure on an inner peripheral surface for being supported by the monolithic refractory.

(1) Annular Block An annular block is composed of two or more divided blocks, and is formed by combining the divided blocks into a ring. That is, each divided block has a shape obtained by dividing an annular block into a plurality of pieces in the circumferential direction. A plurality of annular blocks are connected in a cylindrical shape in the axial direction (longitudinal direction of the water-cooled pipe) so as to surround the water-cooled pipe.

(a) Divided Blocks Divided blocks have a structure in which the divided blocks are annularly combined and fixed by a fixture on the outer peripheral surface. For example, FIG. 1 shows an example of an annular block 1 composed of two divided blocks 1a and 1b. The annular block 1 is composed of two divided blocks 1a and 1b, and the adjacent divided blocks are connected by inserting fixing bolts 3a through protrusions 2a and 2b provided on the outer peripheral surfaces of the divided blocks 1a and 1b and fastening nuts 3b. Fix 1a and 1b together. With such a configuration, it is possible to suppress the movement of the divided blocks in the radial direction. Partial disassembly is possible because the support for the can be removed.

The division block has an uneven structure for being supported by the monolithic refractory on its inner peripheral surface. The uneven structure of the inner peripheral surface of the dividing block is not particularly limited as long as it is a structure that can be supported by the hardened monolithic refractory. A structure in which a chamfered portion 6 is provided on the inner peripheral surface side may be mentioned. In this case, when the annular blocks formed by annularly combining the divided blocks are connected, grooves are formed in the inner peripheral surfaces of the joints between the annular blocks, so that the hardened monolithic refractories support the blocks. It becomes possible to As other examples, as shown in Fig. 6, a structure in which convex portions are formed on the inner peripheral surface of the divided block, a structure in which concave portions are formed on the inner peripheral surface of the divided block, and a grooved portion on the inner peripheral surface of the divided block. A structure in which a ridge portion is formed on the inner peripheral surface of a divided block, and the like are exemplified. Two or more of these structures may be used in combination.

The plurality of divided blocks constituting one annular block may have the same shape or different shapes, but from the viewpoint of processing costs and handling, the plurality of divided blocks have the same shape. preferably Although the number of divided blocks constituting one annular block is not particularly specified, it is preferable that the number is 2 to 4 in consideration of processing costs and handleability.

The dividing block is made of a heat-resistant material, and is made of a porous CaO 6Al ₂ O ₃ material. Alternatively, it is preferably made of hollow alumina or the like.

(b) Fixture Fixtures that support the split blocks in the radial direction should desirably be easily removed during dismantling. Although FIG. 1 shows a fixture consisting of a fixing bolt 3a and a nut 3b, it can also be fixed using U-shaped fixtures 4, 4' as shown in FIGS. Fixing by winding the wire 5 around the perimeter of the divided blocks 1a and 1b can be considered. When dismantling, the fixture may be removed by cutting or the like. The form of the fixture is not limited to these examples.

The material of the fixture is preferably a heat-resistant alloy such as ceramic or kanthal when exposed to a high-temperature atmosphere of 1300° C. or higher, such as in a heating furnace. In the case of an atmosphere of less than 600° C. such as in a low-temperature heat treatment furnace, fixtures made of stainless steel or the like may be used. In addition, since it is exposed to scales in a heating furnace, the fixture may be coated with an anti-seizure agent or a coating agent.

(2) Support structure In addition to supporting the divided blocks in the radial direction, it is necessary to support the divided blocks in the longitudinal direction so that the other divided blocks (annular blocks) do not collapse when removing the worn divided blocks. provides support in the longitudinal direction by means of an uneven structure obtained by molding a monolithic refractory filled in the gap between the annular block and the water cooling pipe. That is, in the present invention, the support structure formed by curing the monolithic refractory works as a heat insulating material and also has a function of supporting the divided blocks (annular blocks).

First, as shown in FIG. 5, an annular block is constructed using divided blocks 1a and 1b having chamfered portions 6 on the inner peripheral surface side of the ends in the longitudinal direction. By using the divided blocks having the chamfered portions 6 in this manner, an annular block having the chamfered portions 6 on the inner peripheral surface side of the longitudinal ends is formed. Next, as shown in FIG. 7, a plurality of annular blocks 1, 1', 1'' are connected and installed on the outer periphery of the water cooling pipe 10. As shown in FIG. By connecting a plurality of annular blocks, a concave portion (groove portion) is formed in the inner peripheral surface of the joint portion between the annular blocks, in which the chamfered portions 6 are opposed to each other. As shown in FIG. 8, the monolithic refractory 11 is placed in the gaps provided between the water cooling pipe 10 and the annular blocks 1, 1', 1'' and recesses (grooves) formed in the joints of the adjacent annular blocks. Pour in and fill. By hardening the monolithic refractory 11, a support structure that supports the division blocks in the longitudinal direction is formed. The hardened support structure, as shown in FIG. 9, has a structure in which ridges are formed at positions corresponding to recesses (grooves) formed in the inner peripheral surface of the annular block. Although not shown, the water-cooled pipe 10 is usually covered with a heat insulating material (such as a heat insulating blanket).

For partial repair, the dividing block must be separable from the cured monolithic refractory (support structure). Separable means that only the division block can be removed without almost destroying the monolithic refractory. In order to make it separable, for example, the dividing block and the monolithic refractory have different compositions so that they do not react, the inner peripheral surface of the dividing block is coated with a release agent in advance, and a tape or fiber blanket is applied to the dividing block. A method such as stretching on the inner peripheral surface of the is conceivable.

The monolithic refractory is filled between the annular block (divided block) and the water cooling pipe. may be emphasized. On the other hand, the monolithic refractory may have a composition with high heat insulating properties, and the dividing blocks may have a composition that emphasizes heat spalling resistance and scale resistance. Alternatively, the water cooling pipe may be covered with a heat insulating material such as a fiber blanket having high heat insulating properties, and may have a three-layer structure of the fiber blanket, the monolithic refractory material, and the divided blocks.

The monolithic refractory should have sufficient fluidity to be filled sufficiently and exhibit strength capable of supporting the block after hardening. Also, if the diameter of the support structure made of the monolithic refractory material changes after cooling, it will be troublesome to construct a new block. Accordingly, fillers other than monolithic refractories can be used as long as they satisfy such conditions, but self-hardening monolithic refractory castables or thermosetting refractory powders are preferably used.

The shape of the projections and depressions of the support structure is not limited as long as it is a structure capable of providing the monolithic refractory with support strength that prevents it from collapsing when the worn divided block is pulled out. For example, a support structure in which a protruding portion is formed, such as a knot of bamboo shown in FIG. 9, a columnar support structure having protrusions 11b shown in FIG. 10, and the like can be considered. 6 may be provided on the inner peripheral surface of the divided block, and a columnar support structure having recesses 11c as shown in FIG. 11 may be provided. Note that the shape of the uneven portion of the support structure is not limited to these examples.

[2] Construction Method of Insulation Structure Covering Water-cooled Pipes The method of the present invention for constructing an insulation structure covering water-cooled pipes comprises:
annularly combining two or more segmented blocks with a removable fixture to form an annular block;
A step of stacking and installing a plurality of the annular blocks in the axial direction so as to surround the circumference of the water cooling pipe;
filling and hardening a monolithic refractory between the plurality of annular blocks and the water cooling pipe to form a support structure made of the monolithic refractory;
The dividing block is characterized by having an uneven structure on an inner peripheral surface for being supported by the monolithic refractory.

The present invention exhibits a high effect when the water-cooled pipe is installed in the vertical direction (vertical direction), but the installation direction of the water-cooled pipe is not particularly limited. For example, the present invention can be applied even when the water cooling pipe is installed horizontally with respect to the ground. In this case, it is expected that the annular block will be prevented from falling, the joint opening between the divided blocks will be suppressed, and a worn block can be easily replaced by removing the fixture.

[3] Method for Repairing a Heat Insulation Structure Covering a Water Cooling Pipe In the heat insulation structure covering a water cooling pipe according to the present invention, when replacing and repairing worn split blocks, the fixtures that support the support structure in the radial direction must be removed. It is only necessary to remove the target divided block by pulling it out or dismantling it, replace it with the removed divided block, insert a new divided block, and fix it again with a fixture to form an annular block. There is no need to re-weld studs, etc., and the heat insulating structure inside the split block can be used as it is without dismantling, so it is economically superior.

The present invention will be described in more detail by the following examples, but the invention is not limited to these examples.

Example 1
It consists of a porous and highly heat-insulating CA6 precast block whose main component is CaO 6Al ₂ O ₃ (hereinafter abbreviated as CA6). were prepared, and combined in a ring to prepare a ring block. Kanthal bolts and nuts were used as fixtures (not shown) for fixing the divided blocks 1a and 1b. As shown in FIG. 12(a), three annular blocks are stacked so as to surround the water-cooled pipe 10, and the three annular blocks 1, 1', 1'' and the water-cooled pipe 10 A monolithic refractory 11 having an alumina composition having a low coefficient of thermal expansion and high strength was filled in the space and cured to prepare a heat insulating structure 20 having a heat insulating structure according to the present invention. The water cooling pipe 10 was previously covered with a heat insulating material 12 (heat insulating blanket). The cured monolithic refractory had the shape shown in FIG. These configurations are shown in Table 1.

The upper and lower portions of the water-cooled pipe 10 of the heat insulating structure 20 thus produced are covered, and as shown in FIG. A water injection hose 14a and a water discharge hose 14b for circulation were connected. As shown in FIG. 13, this heat insulating structure 20 was inserted through an opening 22 provided in the ceiling of an electric furnace 21 for testing and installed in a heating chamber 22 inside the electric furnace 21 for testing. The test electric furnace 21 has a substantially cubic heating chamber 22, a heat generating element 24 for heating the inserted heat insulating structure 20 from the side, and the heat insulating structure 20 and the heat generating element 22 as a whole to keep them warm. It consists of a heat insulating material 25a for. After inserting the heat insulating structure 20, the gap of the opening 22 was filled with the heat insulating material 25b and the lid was put on, and the heat insulating structure 20 was subjected to an evaluation test. By using the test electric furnace 21 having such a configuration, it is possible to test the heat insulating structure 20 under temperature distribution conditions close to those of the actual furnace.

Examples 2-4
The insulation structure of the present invention is made in the same manner as in Example 1 except that the materials (materials) and shapes of the dividing blocks and fixtures, and the monolithic refractories are changed as shown in Tables 1-1 and 1-2. A thermal insulation structure was fabricated. Furthermore, in the same manner as in Example 1, these heat insulating structures were installed in the test electric furnace 21, and an evaluation test of the heat insulating structures was performed.

注(1)：曲げ強度及び圧縮強度は800℃焼成後の値

Note (1): Flexural strength and compressive strength are values after firing at 800°C.

注(1)：曲げ強度及び圧縮強度は800℃焼成後の値

Note (1): Flexural strength and compressive strength are values after firing at 800°C.

In the evaluation test of the heat insulating structures of Examples 1 to 4, one cycle was the process of raising the temperature from room temperature (25 ° C.) to 1300 ° C., holding it at 1300 ° C. for 24 hours, and then naturally cooling it to room temperature. After repeating 3 cycles, the appearance of the divided blocks was visually observed to confirm the presence or absence of cracks.

In all of Examples 1 to 4, the split block could be pulled out simply by removing the fixture for the radial direction. The upper block did not fall down when pulled out, and the support in the longitudinal direction was effective. In addition, there were no cracks or the like in the appearance of the divided blocks. However, in Example 4, the SUS310 of the fixture adhered and had to be cut.

Furthermore, the heat insulating structure produced in Example 1 was applied to a heat insulating structure covering water cooling pipes in a walking beam type heating furnace for hot rolling in the steel production process. The atmosphere in the furnace under heating was 1100-1300°C, and the repair was performed cold.

After being used for about 3 months under heating conditions, the divided blocks at a plurality of locations including the lowermost divided block were pulled out, and it was evaluated whether they could be replaced with new divided blocks. As a result, microcracks were found on the surface of the dividing block before replacement, but the dividing block was not significantly damaged. When performing partial repairs, it was possible to easily pull out the desired split block simply by removing the bolts and nuts, and to replace it by inserting a new split block. In addition, since welding is not required, the construction time can be greatly shortened.

1,1',1''・・・Annular block
1a,1b・・・divided block
2a, 2b・・・Protrusions
3a・・・Fixing bolt
4,4'・・・U-shaped fixture
5... wire
6... Chamfer
7・・・Convex part
10・・・Water cooling pipe
11 Monolithic refractories
11a・・・Protrusion
12 Thermal insulation
13 Lid
14a・・・Water injection hose
14b Drainage hose
21・・・Electric Furnace for Test
22 ... opening
23・・・heating chamber
24 Heating element
25a, 25b・・・Insulation material

Claims (11)

a plurality of annular blocks connected in the axial direction so as to surround the water cooling pipe;
A heat insulating structure covering a water cooling pipe, comprising: a support structure formed by hardening a monolithic refractory filled between the plurality of annular blocks and the water cooling pipe; Composed of two or more combined divided blocks and a fixture that is detachably attached to the outer peripheral side of the divided blocks and fixes the divided blocks to each other ,
A heat insulating structure covering a water cooling pipe, wherein the dividing block has an uneven structure on an inner peripheral surface thereof so as to be supported by the monolithic refractory and is separable from the supporting structure. In the heat insulating structure covering the water cooling pipe according to claim 1,
A water cooling pipe , wherein the split blocks have a structure on an outer peripheral surface for the split blocks to be annularly combined and fixed by the fixture, and the fixture is attached to the structure. Insulation structure that covers the In the heat insulating structure covering the water cooling pipe according to claim 1 or 2,
A heat insulating structure covering a water cooling pipe, wherein the monolithic refractory is monolithic refractory castable or refractory powder. A construction method for a heat insulating structure covering a water cooling pipe, comprising:
forming an annular block by annularly combining the divided blocks by detachably attaching a fixture to the outer peripheral side of two or more divided blocks;
A step of axially connecting and installing a plurality of the annular blocks so as to surround a water cooling pipe;
filling and hardening a monolithic refractory between the plurality of annular blocks and the water cooling pipe to form a support structure made of the monolithic refractory;
A construction method for a heat insulating structure covering a water cooling pipe, wherein the dividing block has an uneven structure on an inner peripheral surface for being supported by the monolithic refractory and is separable from the supporting structure. . In the construction method of the heat insulating structure covering the water cooling pipe according to claim 4,
The divided blocks have a structure on the outer peripheral surface for the divided blocks to be annularly combined and fixed by the fixture, and the fixture is mounted on the structure to cover the water cooling pipe. Construction method of thermal insulation structure. In the construction method of the heat insulation structure covering the water cooling pipe according to claim 4 or 5,
A construction method for a heat insulating structure covering a water-cooled pipe, wherein the monolithic refractory is monolithic refractory castable or refractory powder. A method for repairing the insulation structure according to any one of claims 1 to 3,
a step of removing the fixtures that fix the divided block to be repaired, and pulling out or dismantling the divided block to remove it;
replacing the removed divided block, inserting a new divided block, and combining and fixing them annularly with a fixture to form an annular block. Method. A method for repairing an insulating structure constructed by the method according to any one of claims 4 to 6,
a step of removing the fixtures that fix the divided block to be repaired, and pulling out or dismantling the divided block to remove it;
replacing the removed divided block, inserting a new divided block, and combining and fixing them annularly with a fixture to form an annular block. Method. A dividing block used in the heat insulating structure according to any one of claims 1 to 3,
A divided block comprising: a structure for annularly combining and fixing the divided blocks by the fixture; and an uneven structure for being supported by a monolithic refractory on the inner peripheral surface. A dividing block used in a heat insulating structure constructed by the method according to any one of claims 4 to 6,
A divided block comprising: a structure for annularly combining and fixing the divided blocks by the fixture; and an uneven structure for being supported by a monolithic refractory on the inner peripheral surface. A divided block used in the repair method according to claim 7 or 8,
A divided block comprising: a structure for annularly combining and fixing the divided blocks by the fixture; and an uneven structure for being supported by a monolithic refractory on the inner peripheral surface.

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