JP2002061937A - Duct-modifying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce construction expense by executing the modifying construction of expansion joints without using incidental facilities for construction as much as possible. SOLUTION: In the duct-modifying method for modifying the expansion joint 4 to a new expansion joint part 4A with a duct 2 comprising first and second duct parts 2A and 2B being connected so that they communicate each other via the expansion joint part 4 as a target, a carrying-in entrance 6 for carrying in repairing machinery and materials for connecting the inside and outside of a duct space V is provided at one portion of the expansion joint 4, a material 7 for new expansion joints being divided into a plurality of portions in advance is carried into the duct via the carrying-in entrance 6, a tentative fixation member 8 is mounted across the first and second duct parts 2A and 2B for stabilizing the posture of both the duct parts 2A and 2B, then a gap K over the entire periphery in the peripheral direction of the duct is made to the expansion joint part 4 for cutting, and at the same time the material 7 for new expansion joints is assembled to the inside of the expansion joint 4, thus integrating both the ducts 2A and 2B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a duct composed of a first duct portion and a second duct portion which are connected to each other via an expansion joint portion (for example, a large duct such as a boiler stack for power generation). The present invention relates to a duct repair method for repairing the expansion joint part to a new expansion joint part.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 1, in a boiler for power generation, a dust collector 3A, a denitration device 3B, and a desulfurization device ( (Not shown) and the like, and these are connected by a duct 2 to form an exhaust passage. The duct 2 is provided with an expansion joint 4 in order to absorb the effects of thermal expansion and contraction caused by the operation / stop of the boiler main body 1A and to prevent each device from being adversely affected. There are many. The expansion joint part 4 referred to here is, for example, a metal bellows, and as shown in FIG. 7, is made of a thin metal plate formed in a bellows shape over the first duct part 2A and the second duct part 2B. The bellows 5 is attached. However, with the use of the duct, for example, the expansion joint portion tends to be greatly consumed due to the influence of, for example, cracks due to the action of excessive stress or corrosion due to corrosion components in rainwater or exhaust gas. Therefore, it is necessary to repair the expansion joint. Conventionally, as this type of duct repair method, as shown in FIG. 7A, a work scaffold 20 is formed from the ground outside the expansion joint portion to be repaired, and then the first duct portion 2A and the second The duct portion 2B and the duct member 2B are temporarily fixed with the reinforcing steel material 21 to suppress mutual displacement. (If a heat insulating layer is provided on the outer peripheral portion of the duct, the heat insulating layer is removed and a reinforcing steel material is attached.) Then, a ring-shaped (generally, interposed between the duct portions 2A and 2B) (See FIG. 7 (b)), and a new expansion joint 4A is installed on the old expansion joint removal trace, and then the reinforcing steel material 21 is removed and the work scaffold is removed. 2
0 was dismantled and removed (see FIG. 7C).

[0003]

According to the above-mentioned conventional duct repair method, it takes time to set up and remove work scaffolds, and also requires the use of crane or the like for carrying in and out of materials and repairing expansion joints. Lifting equipment needs to be resident,
There was a problem that the cost of the expansion joint repair work was high. Also, if the expansion joint is located at a high place or there are many obstacles near the site, installation and removal of the work scaffolds will be troublesome, and operation will be performed from a distance without the cleanliness approaching the site. If it is necessary, it is necessary to prepare a large-sized clean, and there is a problem that the cost is further increased.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, to carry out a renovation work of an expansion joint without using as much as possible ancillary facilities for construction, and to reduce the cost of the construction work. Is to provide.

[0005]

As shown in FIG. 2, a first duct portion 2A and a second duct portion 2 which are connected to each other via an expansion joint 4 are connected to each other.
B, the expansion joint 4
In the duct repair method for repairing the expansion joint part 4A as a new expansion joint part 4A, a part of the expansion joint part 4 or the expansion joint part 4
A part of the ducts 2A and 2B in the vicinity is provided with a carry-in entrance 6 for refurbishment equipment which can freely communicate inside and outside of the duct space V, and a new expansion joint material 7 previously divided into a plurality of parts is provided. It is carried into the duct through the carry-in port 6 and the expansion joint 4
Inside the first duct portion 2A and the second duct portion 2
After the provisional fixing member 8 is attached to the state extending over B and the posture of the two duct portions 2A and 2B is stabilized, the new expansion joint material 7 is assembled inside the expansion joint portion 4 to form the two duct portions 2A and 2B. The point is to unite each other.

According to the characteristic structure of the first aspect of the present invention, if the repair equipment is carried into the duct from the carry-in entrance, the repair work of the expansion joint can be proceeded inside the duct. It is possible to proceed with the work without providing a large-scale work scaffold and without preparing a large-sized clean, and it is possible to reduce the cost of the expansion joint repair work. In addition, since the work inside the duct is mainly performed, even if a heat insulation layer is formed on the outer periphery of the expansion joint part, it is possible to carry out the expansion joint repair work while leaving the heat insulation layer In addition, the work of removing and installing the heat insulation layer can be omitted and the expansion joint renovation work can be performed efficiently.

As shown in FIG. 3, a characteristic feature of the second aspect of the present invention is that the temporary fixing member 8 is attached to stabilize the posture of the two duct portions 2A and 2B, and then the cut K along the circumferential direction of the duct. In the expansion joint part 4.

According to the characteristic configuration of the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, the old expansion joint can be cut only and does not need to be removed. Therefore, it is possible to reduce the amount of waste material to be treated, and in this regard, it is also possible to reduce the cost of the expansion joint repair work by reducing the waste treatment cost. In addition, the force acting between the first and second ducts is not directly received by the remaining old expansion joint part (or hardly received) because the old expansion joint part is cut. With the new expansion joint, it is possible to demonstrate the elasticity and strength as designed. That is, the design of the expansion joint can be easily performed by simplifying the force transmission path.

As shown in FIG. 3, the material of the new expansion joint material 7 is a thin metal thick new joint body 7A that can expand and contract in the duct flow direction, and the new joint body 7A. And a thick metal flange portion 7B to be attached to both the duct portions 2A and 2B.

In general, when welding a thin metal and a thick metal, extremely high construction management is required, but it is very difficult to obtain good results in ordinary construction management on site. However, the attachment parts of both ducts are, of course, made of thick metal, and a new joint body made of thin pressure metal is welded to the thick metal in order to expect elasticity. Direct mounting is very laborious and tends to degrade quality. According to the characteristic configuration of the third aspect of the present invention, in addition to achieving the effects of the first or second aspect of the invention, the thickness of the new joint body and the thickness of attaching the new joint body to the two duct portions are provided. Since the material for the new expansion joint is constructed by integrating the metal flange part with the meat, on-site welding can be performed on the metal flange part and both duct parts, and good joint quality can be obtained even on-site work. Can be obtained. Furthermore, since the portions to be welded are the two duct portions and the metal flange portion,
Since both have a certain width in the contact surface portion, and the relative position can be changed within the width, the flexibility of the mounting position of the new expansion joint material can be improved. Therefore, even when the remaining old expansion joint part or a part of the duct part is deformed abnormally and the material for the new expansion joint cannot be set at the proper position by a normal method, the two duct parts and the metal Since it is easy to secure a certain width in the contact part with the flange part, it is possible to shift the position appropriately within the width and attach it to the regular position, and to improve the quality and on-site workability Becomes possible.

Note that, as described above, reference numerals have been written for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the accompanying drawings.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, portions denoted by the same reference numerals as those of the conventional example indicate the same or corresponding portions.

FIG. 1 shows a boiler 1 for power generation. The boiler 1 includes a boiler body 1A, a dust collector 3A,
Each device 3 such as a denitration device 3B and a desulfurization device (not shown) is provided, and these are connected by a duct 2 to form an exhaust passage.

The duct 2 absorbs the effects of thermal expansion and contraction caused by the operation and shutdown of the boiler main body 1A, and prevents each device from adversely affecting each other.
An expansion joint 4 is provided. The expansion joint part 4 is constituted by a bellows-like bellows 5 made of a thin metal plate (FIGS. 2 and 3).
), The bellows 5 is welded at both end edges thereof to the first duct portion 2A on one side and the second duct portion 2B on the other side, respectively, and is attached so as to extend over both duct portions 2A and 2B. I have. Therefore, for example, as described above,
When the two ducts 2A and 2B relatively move due to thermal contraction, the movement can be absorbed by the elasto-plastic deformation of the bellows 5. However, the bellows 5 is formed of a thin metal plate, is subject to repeated elasto-plastic deformation forces, and is susceptible to adverse effects from rainwater and corrosive components in exhaust gas passing through the duct 2. For this reason, the wear tends to be particularly severe. Therefore, it is necessary to rehabilitate the duct part to replace the expansion joint part 4 with a new expansion joint part.

The method for repairing the duct in the present embodiment is for repairing the expansion joint 4 shown in FIG. 2 to a new expansion joint 4A shown in FIG. 3, and the procedure will be described below.

[1] At the ceiling of the expansion joint 4, a carry-in entrance 6 for carrying in the refurbishment equipment is provided, which can freely communicate inside and outside the duct space V. Specifically, the ceiling of the expansion joint 4 is cut out from the duct space V to form the carry-in entrance 6 (see FIG. 2A). When a heat insulating layer is formed along the outer peripheral portion of the expansion joint 4, the heat insulating layer is also cut. By the way, since the carry-in entrance 6 is formed in the ceiling of the expansion joint part 4, when carrying the repair equipment into the duct through the carry-in entrance, it can be carried out only by hanging down the load from above the carry-in entrance, For example, it is possible to carry out the refurbishment equipment in a very efficient manner, as compared with methods such as horizontal pulling of a load and lifting of a load. In addition, since the duct ceiling can be used as a working scaffold as it is, there is no need to construct a new scaffold for carrying in the repair equipment, thereby improving work efficiency and reducing costs. Becomes

[2] The new expansion joint material 7 divided in advance into a plurality of pieces is carried into the duct 2 through the carry-in port 6 (see FIG. 2B). For this work,
The new expansion joint material 7 carried into the site is lifted above the carry-in port 6 by means of a crane, and carried in from the carry-in port 6. The new expansion joint material 7 is divided into a plurality in the circumferential direction of the joint (see FIG. 5).

[3] After forming a scaffold or the like in the duct 2 if necessary, the temporary fixing member 8 is placed inside the expansion joint 4 so as to extend over the first duct 2A and the second duct 2B. To stabilize the posture of the two duct portions 2A and 2B (see FIG. 2C). The temporary fixing member 8 includes:
A state in which the ducts 2A and 2B are made of H-section steel that has the strength to restrain them. The height is set so as not to hinder the repair of the new expansion joints. The required number can be attached to the machine by welding. In addition, if the temporary fixing member 8 is cut and removed when the duct repair is completed, the restraint of the two duct portions 2A and 2B can be released.

[4] The cuts K in the circumferential direction of the duct are sequentially cut into the expansion joint portion 4 and cut, and the new expansion joint material 7 is sequentially assembled inside the expansion joint portion 4 over the entire circumference to form both ends. The duct portions 2A and 2B are integrated (see FIGS. 2 (d) and 3). The cutting of the expansion joint 4 ensures that the force acting between the two duct portions 2A and 2B is transmitted only to the new expansion joint material 7 after completion of the duct repair work, so that good elasticity can be secured. It is implemented in order to. As shown in FIG. 3, the new expansion joint material 7 includes a bellows (corresponding to a new joint body) 7A formed in a bellows shape by a thin metal plate that can expand and contract in the duct flow direction, and both side edges of the bellows 7A. And a sub-flange member (corresponding to a flange portion) 7B made of a thick metal, which is welded and integrated in the factory in advance. Then, the two duct portions 2A and 2B to which both sub-flange members 7B are to be attached are set in advance.
The main flange member 10 made of a thick metal is fixed by welding as an attachment auxiliary material. And both ducts 2A and 2
In attaching the new expansion joint material 7 to B, the sub-flange member 7B is fixed to the main flange member 10 by welding. In addition, when the main flange member 10 is attached to both the duct portions 2A and 2B, as shown in FIG. 4, in order to easily perform a welding operation between the sub-flange members 7B adjacent in the joint circumferential direction. The main flange member 10 is removed from the portion corresponding to the connection portion between the sub-flange members 7B so that the sub-flange members 7B can be welded together and the quality inspection after welding can be performed reliably. After that, the main flange member 10
The other main flange member 10a is fitted into the portion from which the main flange member 10a has been removed, and is welded and integrated with the main flange member 10 attached earlier. Incidentally, the main flange member 1
Since the sub-flange member 7B can be attached to the sub-flange member 7B in a slightly displaced direction along the radial direction of the duct, for example, the remaining portions of the duct portions 2A and 2B or the old expansion joint portion 4 are abnormal. Even if it is difficult to install the new bellows 7A at the regular position by the normal method, the sub-flange member 7B can be fixed at the regular position by shifting, and the quality and on-site workability can be improved. improves.

[5] After the installation of the new expansion joint material 7 is completed, if it is necessary to reduce the resistance of the exhaust gas passing through the duct 2, a metal guide plate 9 is attached by welding. However, the guide plate 9 is attached so as not to hinder the expansion and contraction of the bellows 7A.

According to the duct repair method of the embodiment,
Even if the position of the expansion joint is high or there are many nearby obstacles, the work can be efficiently performed without starting up a large-scale work platform from the ground.
Further, since it is not necessary to prepare large-sized clean for a long period of time, the cost of the duct repair work can be reduced. Further, even if a heat insulating layer is formed on the outer peripheral portion of the expansion joint portion, the repair work can be carried out while the heat insulating layer remains, and the duct repair work can be carried out quickly. In addition, the old expansion joint part is only required to make a cut, and it is not necessary to remove it.
In addition, it is possible to further reduce costs by reducing waste disposal costs.

[Another Embodiment] Another embodiment will be described below.

<1> The formation of the new expansion joint 4A is not limited to the method of forming it inside the old expansion joint over the entire periphery of the joint as described in the previous embodiment. As shown in the above, regarding the ceiling part of the joint part,
After removing all of the old expansion joint 4, a new expansion joint 4 </ b> A may be formed on its trace. In this case,
Since the upper surface of the duct 2 can be used as a scaffold, there is no need to assemble the scaffold from the ground as in the above-described embodiment, and advantages in both cost and construction can be expected. Further, according to this embodiment, since the duct space V in the joint portion can be secured more widely, it is possible to reduce the resistance to the exhaust gas moving in the duct. <2> The shape of the duct 2 and the joints 4.4A is
The present invention is not limited to those described in the above embodiment, and can be applied to other widely known duct / joint portions. <3> The duct repair method is not limited to the repair of the duct attached to the power generation boiler described in the above embodiment, and can be applied to other ducts. In short, by adopting a duct (such as one installed at a high place or one with a large channel cross section) that originally requires the work scaffold to be raised from the ground to the construction position,
It can be more effective. These are collectively called ducts. <4> The expansion joint is not limited to the one attached to the first and second ducts of the duct body as described in the previous embodiment. For example, a joint is formed between two adjacent devices. In such a case, it may be configured to be attached to the first duct portion of the device and the second duct portion of the device, and these are generically called expansion joint portions. <5> The carry-in entrance is not limited to the one formed at the ceiling of the expansion joint part 4, but the duct parts 2A and 2A close to the expansion joint.
It may be formed on the ceiling of B. These are collectively called the entrance. <6> The cut K is not limited to the cut K provided along the entire circumference of the expansion joint 4 as described in the previous embodiment, but the cut K along the circumferential direction of the expansion joint 4. May be provided in a discontinuous state, and these are referred to as breaks. In short, both ducts 2A
-What is necessary is just to be able to make the force which acts between 2B difficult to transmit via the old expansion joint part 4.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a duct portion of a boiler.

FIG. 2 is a side view explanatory view showing a duct repair method.

FIG. 3 is a sectional view of a main part showing a new expansion joint.

FIG. 4 is a front view of the duct shaft as viewed in the axial direction, showing an assembled state of a main flange member.

FIG. 5 is a front view of the duct shaft center direction showing a divided assembly state of the sub-flange member and the bellows.

FIG. 6 is a side sectional view showing a new expansion joint part according to another embodiment.

FIG. 7 is an explanatory side view showing a conventional duct repair method.

[Explanation of symbols]

 2 Duct 2A First duct part 2B Second duct part 4 Expansion joint part 4A New expansion joint part 6 Carry-in port 7 New expansion joint material 7A New joint body 7B Flange part 8 Temporary fixing member K Cut V Duct space

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K070 AC01 AC11 3L080 AA09 AB06 AC05 AD04

Claims (3)

[Claims] 1. A duct repair method for repairing a duct composed of a first duct portion and a second duct portion connected to each other through an expansion joint portion to a new expansion joint portion for a duct. A part of the expansion joint part, or a part of the duct part in the vicinity of the expansion joint part, is provided with a refurbishment equipment carrying-in entrance which can freely communicate inside and outside of the duct space, and is divided into a plurality of parts in advance. The new expansion joint material that has been set is carried into the duct through the carry-in port, and a temporary fixing member is attached to the inside of the expansion joint portion so as to extend over the first duct portion and the second duct portion. A duct repair method for assembling the new expansion joint material to the inside of the expansion joint portion and integrating the two duct portions after stabilizing the posture of each other. 2. The duct repair method according to claim 1, wherein a cut along the duct circumferential direction is formed in the expansion joint after the provisional fixing member is attached to stabilize the posture of the two ducts. 3. The new expansion joint material is formed by integrating a thin metal new joint body which can expand and contract in a duct flow direction and a thick metal flange for attaching the new joint body to the two duct portions. The duct repair method according to claim 1, wherein the duct repair method is configured.