JP3781863B2 - Duct reinforcement structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a boiler duct, and more particularly to a joint structure suitable for enhancing the rigidity of a corner joint portion of a flange of an internal heat retaining structure type.
[0002]
[Prior art]
7 to 11 show examples of the conventional structure of the internal heat retaining structure method. FIG. 7 shows the external shape of a boiler duct having a conventional structure, and FIG. 8 is a cross-sectional view perpendicular to the gas flow of the duct. FIG. 9 is a cross-sectional view similar to FIG. 8 and shows a case where the inclination of the duct surface is steep. 10 is a cross-sectional view taken along the line EE of FIG. 8 and shows the structure of the corner joint portion of the flange, and FIG. 11 is a view of FIG. 10 viewed from the CC direction.
[0003]
The duct of the power generation boiler is formed as a passage for guiding the exhaust gas having a temperature of 300 to 600 ° C. and a pressure of 200 to 1500 mmAq to the chimney, and the entire circumference is rectangular with a metal casing 1 of 6 to 9 mm. ing.
[0004]
Stiffeners 4 are provided with a span pitch that can withstand the strength of the casing 1 in the gas flow direction so as to maintain the strength that can withstand the pressure inside the duct (even if the stiffener 4 is continuous along the entire length of the casing 1 surface). In FIG. 8, a discontinuous stiffener is shown.) Further, a flange 2 is provided on the entire circumference of the casing in a direction perpendicular to the gas flow, and the stiffener 4 and the flange 2 serve as the casing 1. It is the structure fixed by welding continuously or intermittently.
[0005]
In this case, since the casing temperature is the same as the gas temperature in the case of the external heat retention type, it is designed so that the internal pressure is balanced by connecting a stay such as a pipe between the flanges. However, in the case of the internal heat insulation structure, the internal stay cannot be installed due to the temperature difference problem, and ultimately the internal pressure is all handled by the external flange 2. It is necessary to make up a member of a considerable size.
[0006]
Here, the joining of the corner members of the flanges 2 is the maximum moment that acts on the flange by adopting a rigid joint (joint structure that can transmit the end moment) to reduce the overall deflection of the flange and the bending moment. Alternatively, deflection can be reduced and a very economical structure can be provided.
[0007]
However, when the duct has a rectangular parallelepiped shape, the connection of the corners of the flange can be easily rigidly connected. However, when each face of the duct is inclined, it acts at right angles to the duct casing surface. In order to effectively arrange the flange to the internal pressure being applied, it is necessary to align the core of the strong axis of the flange at a right angle to the casing surface. However, if the flange 2 is arranged at a right angle on each casing surface, the joint portion of the flange end portion of each corner portion is engaged with a shape shifted by an inclination angle, and the end portion cannot be rigidly joined. become.
[0008]
If the end of the flange corner is to have a rigid joint structure, the cores of the flanges must be aligned. Therefore, the flange mounting angle is inclined by an angle θ with respect to the direction perpendicular to the casing as shown in FIG. Therefore, in the case of a duct having a steep angle (see FIG. 9), the strength of the flange is greatly reduced with respect to the direction in which the pressure acts (the flange core is inclined with respect to the pressure acting direction). And difficult to attach to the casing (complexity of attaching a plurality of flanges with appropriate angles to the casing surface), and welding of flanges with angles to the casing There was a problem such as difficulty.
[0009]
10 and 11, the flange 2 is attached at an angle θ with respect to the direction perpendicular to the casing 1, so that the end portion of the flange at the corner portion has a rigid joint structure. FIG.
[0010]
[Problems to be solved by the invention]
In the prior art structure, when the duct diameter is changed and the inclination of each surface becomes large, the structure of the corner portion can be easily rigidly connected by effectively utilizing the strength of the flange. That was a challenge.
[0011]
The object of the present invention is to eliminate the above-mentioned problem by employing a contact plate structure in the duct corner portion and a reinforcing plate in the vicinity of the corner portion as shown in FIGS.
[0012]
[Means for Solving the Problems]
The problem is that the flange is installed perpendicularly to the duct casing, and a contact plate is installed at the duct corner where the flange cross-section is displaced, so that the load applied to each flange can be passed between each other (rigid connection). To achieve.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The reinforcing structure which is embodiment of this invention is shown in FIGS. Here, FIG. 1 shows the external shape of the boiler duct of the present invention, and FIG. 2 is a cross-sectional view perpendicular to the gas flow of the duct. 3 is a cross-sectional view taken along the line AA of FIG. 2 and shows a structure having a contact plate at a corner joint portion of the flange, and FIG. 4 is a view of FIG. 3 viewed from the flange 2a side. FIG. 5 is a view showing the arrangement relationship between the reinforcing plate provided in the vicinity of the corner joint portion of the flange, the flange, and the casing. FIG. 6 is a diagram showing an arrangement relationship between the contact plate and the flange at the corner joint portion of the flange.
[0014]
Reference numeral 1 denotes a duct casing, 2 a flange, 3 a backing plate, 4 a stiffener, and 5 a reinforcing plate.
[0015]
The structure of the internal heat insulation duct is the same as that of the conventional structure except for the flange, the duct casing 1, the flange (reinforcing material) 2, the contact plate 3 that joins the flanges (reinforcing material) to each other at the end, and the duct casing. It comprises a stiffener 4 that reinforces the flange and a flange reinforcing plate 5 provided in the vicinity of the duct corner.
[0016]
As shown in FIG. 2, the flange (reinforcing material) 2 is installed perpendicular to the duct casing 1, and the deviation of the cross section between the flanges (reinforcing materials) at the corners of the casing surfaces with different inclinations is as follows. A contact plate 3 provided at the corner is installed and connected (see FIGS. 3 and 6). In addition, a reinforcing plate 5 having a flange and a casing as a fixed structure is provided in the vicinity of the corner portion.
[0017]
The stiffener 4 may be continuous along the entire length of the casing 1 surface, or may be discontinuous. FIG. 2 shows a discontinuous stiffener. The stiffener 4 is structured to be welded and fixed continuously or intermittently along the casing 1.
[0018]
Further, a flange 2 is provided on the entire circumference of the casing in a direction perpendicular to the gas flow, and the flange 2 is welded and fixed along the casing 1 continuously or intermittently. In FIG. 2, the flange is illustrated as a T-shaped steel, but the present invention is not limited to this shape.
[0019]
As shown in FIG. 6, the end portion of the corner portion of the flange 2 is fixed by welding or the like with the entire edge abutting against the contact plate 3. Further, as shown in FIG. 5, the reinforcing plate 5 is provided on both sides of the T-shaped steel in the vicinity of the duct corner portion and is appropriately welded and fixed to the casing 1 and the flange 2 to improve the strength of the flange end portion in the corner portion. I am trying.
[0020]
By providing the backing plate and the reinforcing plate having the structure as described above, a load applied to each flange can be transmitted to other members via the backing plate 3 and the reinforcing plate 5, and bending due to a load such as pressure is performed. The moment can be borne at the corner. At this time, the load transmission between the flanges is transmitted by the bending rigidity of the backing plate 3 installed in the corner portion, so that the bending energy is absorbed by the elastic deformation of the backing plate. Compared with the conventional structure, the stress generated around the flange of the part could be reduced by 71% in the model test.
[0021]
Here, the backing plate has a function of joining flange ends that are misaligned with each other and a function of improving the strength of the flange ends, and the reinforcing plate 5 is fixed by welding as shown in FIG. The strength of the flange end is further improved by the structure and arrangement.
[0022]
As described above, according to the present invention, the flanges to be joined to each other are connected through the contact plate, as the flange is installed perpendicularly to the casing surface (acting effectively in the duct internal pressure). At the same time, the strength of the flange end is improved. That is, the flange according to the present invention can sufficiently exhibit the capability even with respect to a load applied perpendicularly to the duct casing, and is easy to mount because it is perpendicular to the casing.
[0023]
In other words, the present invention can perform load transmission between the flanges via the contact plate by integrally welding and fixing the flange plate and the flange provided at the flange connection portion with sufficient rigidity (more than the flange plate thickness). Therefore, it becomes possible to bear the bending moment generated in the flange by the load acting on the duct such as pressure at the corner portion.
[0024]
As a result, the flange can be installed perpendicularly to the duct casing, the original rigidity of the flange can be exhibited, and the flange can be installed easily.
[0025]
【The invention's effect】
According to the present invention, in the structure in which the diameter of the internal heat insulation duct changes, the load transmission between each member of the duct corner portion where the flange cross section of the joint portion is shifted can be easily performed, and the strength is enhanced by the bending rigidity of the backing plate. The
[0026]
Further, by adopting the present invention in the corner portion, the reinforcing material can be installed perpendicularly to the duct casing, and attachment is facilitated.
[Brief description of the drawings]
FIG. 1 is a diagram showing an external shape of a boiler duct according to the present invention.
FIG. 2 is a cross-sectional view perpendicular to the gas flow in the duct.
3 is a cross-sectional view taken along the line AA of FIG. 2 and shows a structure having a contact plate at a corner joint portion of a flange.
4 is a view of FIG. 3 as viewed from the flange 2a side.
FIG. 5 is a diagram showing a positional relationship between a reinforcing plate provided in the vicinity of a corner joint portion of a flange, a flange, and a casing.
FIG. 6 is a diagram showing an arrangement relationship between a contact plate and a flange at a corner joint portion of the flange.
FIG. 7 is a view showing an external shape of a boiler duct having a conventional structure.
FIG. 8 is a cross-sectional view perpendicular to the gas flow in the duct.
FIG. 9 is a cross-sectional view similar to FIG. 8, but showing a case where the inclination of the duct surface is steep.
FIG. 10 is a cross-sectional view taken along the line EE of FIG. 8, showing the structure of the corner joint portion of the flange.
FIG. 11 is a diagram when FIG. 10 is viewed from the CC direction.
[Explanation of symbols]
1 Duct casing 2 Flange 3 Contact plate 4 Stiffener 5 Reinforcement plate

Claims (2)

A reinforcing structure for a duct in which a flange of a steel mold is installed over the outer periphery of a rectangular duct having a different diameter,
Installing the flange of the steel shape in a direction perpendicular to the surface of the casing;
A reinforcing structure for a duct, characterized in that a backing plate is interposed between the flanges to be connected to each other at a corner portion of the duct, and the backing plate and the flange are fixedly joined. The duct reinforcing structure according to claim 1,
A duct reinforcing structure comprising a reinforcing plate fixedly joined to the flange and the casing in the vicinity of the corner portion.

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