JPH05644Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a boiler furnace wall that can prevent cracks from occurring at the lower end of the sub-side wall.

[Prior Art] A conventional boiler and a boiler furnace wall will be explained with reference to FIG. The heating section 2 is suspended from a tower-like steel frame 4 by a hanging rod 5. The furnace 1, the rear heat transfer section 2, and the sub-side wall 3 are constructed by arranging a large number of water pipes in parallel and connecting the water pipes with fins. An outlet header 7 is attached.

The fuel is blown into the lower part of the furnace 1 and combusted, and the combustion gas is sent from the lower part of the furnace 1 to the rear heat transfer section 2,
It is exhausted to the outside through a flue (not shown). still,
A drum or a steam/water separator 8 is attached to the upper part of the furnace 1, and a superheater, reheater, energy saver, etc. (not shown) are attached inside the rear heat transfer section 2 to separate water and steam. It's starting to heat up.

[Problems to be Solved by the Invention] In such a boiler furnace wall, it has been a problem that cracks occur near the lower ends 9, 9' of the side wall of the sub-side wall 3, especially near 9. The discovered cracks are repaired and reinforced as appropriate, but even after the repairs and reinforcement, new cracks are found near the lower ends 9 and 9' of the same sub-side wall 3 every time a periodic inspection is carried out. Even after the crack was discovered and repaired and reinforced, it was not possible to prevent the crack from occurring.

Originally, the lower ends 9, 9' of the sub-side wall 3 have a shape where stress tends to concentrate, and the boiler expands during cold boiling when the operation is stopped and during warm boiling during operation, causing various parts of the boiler to be easily concentrated. The center of gravity of the furnace 1 moves, that is, during warming, the lower part of the furnace 1 supported by the hanging rod 5 is displaced to the left in FIG.
The tensile force that tends to shift to the right in the figure (i.e. splitting phenomenon), and the furnace 1 and the rear heat transfer section 2
It is believed that cracks occur in the lower ends 9, 9' due to a complex relationship between tensile force, shearing force, etc. generated based on the elongation difference due to the temperature difference between the lower end portions 9 and 9'.

If such a crack occurs, there is a risk that combustion gas or steam may leak from the boiler furnace wall or the boiler may be damaged, which is currently a major problem.

In view of the above-mentioned circumstances, it is an object of the present invention to provide a boiler furnace wall in which cracks do not occur at the lower end of the side wall of the sub-side wall.

[Means for Solving the Problems] In the present invention, in a boiler furnace wall formed by connecting a furnace and a rear heat transfer section by a sub-side wall, the last tube constituting the side wall of the furnace has a lower end of a fin constituting the sub-side wall. At a higher position, there is an inverted Y-shaped Y-shaped tube that branches into two in a large arc, and no fins are provided below the Y-shaped tube to separate the side wall and sub-side wall of the furnace. This is something that hangs over the boiler furnace wall.

[Effect] When tensile force etc. acts between the furnace and the sub-side wall, Y
Above the Y-shaped tube, the Y-shaped tube with deformation strength can withstand tensile forces, etc., and below the Y-shaped tube, the side wall and sub-side wall of the furnace are separated, allowing elastic deformation of both to absorb stress. -Relaxes and prevents cracks from occurring at the lower end of the secondary side wall.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of the present invention, and shows the boundary between the lower end 9 of the sub-side wall 3 and the furnace 1, where cracks are particularly likely to occur in a boiler having a configuration similar to the conventional one shown in FIG. There is.

The side wall of the furnace 1 has a large number of evaporation tubes 10 arranged in parallel,
The evaporator tubes 10 are connected by fins 11, and the sub-side wall 3 has a large number of superheater tubes 12 arranged in parallel, and the superheater tubes 12 are connected by fins 13. are doing.

Among the evaporation tubes 10 forming the side wall of the furnace 1, the position above the lower end of the fin 13 forming the sub side wall 3 of the last one evaporation tube 10 located at the boundary with the sub side wall 3 is as follows: Using an inverted Y-shaped Y-shaped pipe 14 whose lower end draws a large arc and splits into two, it branches into two evaporation branch pipes 15 and 16, and one evaporation branch pipe 15 is connected to the fin 11 on the furnace 1 side. and form part of the side wall of the furnace 1, and the other evaporation branch pipe 1
6 to the fin 13 on the side of the sub-side wall 3.
The evaporation branch pipe 16 on the side of the sub-side wall 3 is extended downward to a required length that can be freely deformed, and its lower end merges with the evaporation branch pipe 15 on the furnace 1 side. A space 17 is formed therebetween, separating the side wall of the furnace 1 and the sub-side wall 3.

Further, the evaporator tube 10 and superheater tube 12 adjacent to the evaporator tube 10 provided with the Y-shaped tube 14 are
Bends 18 and 19 are given to the upper portions to join the evaporator tube 10 and the superheater tube 12 located on the side away from the Y-tube 14, respectively.

Note that 20 is an arch-shaped notch formed at the lower end of the fin 13 on the side of the sub-side wall 3.

When a tensile force or the like acts on the boundary between the side wall and the sub-side wall 3 of the furnace 1, the Y-tube 14 has a large arc shape above the installation position and has deformation strength, making it difficult for stress to concentrate. As a result, the space 17 is formed below the installation position of the Y-shaped pipe 14 at the boundary portion, so that the evaporation branch pipe 16 and the like easily undergo elastic deformation to absorb and relieve stress. .

Therefore, both the improvement in the yield strength due to the Y-tube 14 and the elastic deformation of the evaporation branch pipe 16 due to the space 17 are combined, and the occurrence of cracks at the lower end 9 of the side portion of the sub-side wall 3 is prevented.

Moreover, as mentioned above, the side wall and sub-side wall 3 of the furnace 1
When the concentration of stress acting on the boundary between the lower end 9 and the lower end 9 is alleviated, the stress concentration on the boundary between the rear heat transfer section 2 and the lower end 9' of the sub-side wall 3 is also alleviated. It turns out. Furthermore, if necessary, a structure similar to that of the above embodiment may be implemented at the boundary between the rear heat transfer section 2 and the lower end 9' of the sub-side wall 3.

FIG. 2 is an explanatory diagram of another embodiment of the present invention,
In a configuration substantially similar to that in FIG. 1, the evaporation branch pipe 16 on the side of the sub-side wall 3 is extended, and
5, instead of merging into evaporation branch pipe 1
The lower end of the evaporation branch pipe 16' is closed so that the evaporation branch pipe 6' is not extended. (The lower end of the Y-shaped tube 14 on the side of the sub-side wall 3 may be closed instead of providing the evaporation branch pipe 16').

Even if this is done, Y-shaped tube 1 with high deformation strength
4, and a space 17' is formed between the side wall of the furnace 1 and the sub-side wall 3 below the Y-tube 14 to separate them. Cracks on the lower end 9 of the side wall are prevented.

It should be noted that the boiler furnace wall of the present invention is not limited to the above-described embodiments, and it goes without saying that various changes may be made without departing from the gist of the present invention.

[Effects of the invention] As explained above, according to the boiler furnace wall of the present invention, among the tubes forming the side wall of the furnace, the rearmost tube located at the boundary with the sub side wall forms the sub side wall. At a position above the lower end of the fin, an inverted Y-shaped tube that branches into two in a large arc is installed, and the structure is such that the side wall and sub-side wall of the furnace below the Y-shaped tube are separated. When a tensile force, etc. acts between the furnace and the sub-side wall, the Y-shaped tube has deformation strength above the Y-shaped tube, and the Y-shaped tube can withstand the tensile force, etc.
Since the side wall and sub-side wall of the furnace are separated below the tube, elastic deformation occurs easily in both, absorbing and relaxing stress, and as a result, preventing cracks from occurring at the lower end of the sub-side wall. Therefore, an excellent effect can be achieved in that damage to the boiler can be prevented.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of the present invention, FIG. 2 is an explanatory diagram of another embodiment of the present invention, and FIG. 3 is an explanatory diagram of a conventional example. In the figure, 1 is the furnace, 2 is the rear heat transfer section, 3 is the sub-side wall,
9, 9' are lower ends, 10 are evaporation tubes, 11, 13
is the fin, 12 is the superheater tube, 15, 16, 16'
is an evaporation branch pipe, and 17 and 17' are spaces.

Claims (1)

[Scope of utility model registration request] The last tube constituting the side wall of the furnace in the boiler furnace wall formed by connecting the furnace and the rear heat transfer section with a sub-side wall is located above the lower end of the fins constituting the sub-side wall, drawing a large arc 2. A boiler furnace wall having a Y-tube in an inverted Y-shape that branches into two, and having no fins below the Y-tube to separate the side wall and sub-side wall of the furnace.