JPH05645Y2 - - 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 side wall of the sub-side wall.

[Prior art] A conventional boiler and boiler furnace wall are shown in Figures 2 and 3.
To explain with a diagram, a furnace 1 constituting a boiler
and the rear heat transfer part 2 are connected by a sub-side wall 3,
The furnace 1 and the rear heat transfer section 2 are suspended from a tower-shaped steel frame 4 by hanging rods 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 10 in parallel and connecting the water pipes 10 with fins 11. 3
An inlet header 6 and an outlet header 7 for the water pipes 10 constituting the water pipe are attached.

The fuel is blown into the lower part of the furnace 1 and burned, and the fuel 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).

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 water. It is designed to heat steam.

[Problems to be Solved by the Invention] In such a boiler, there has been a problem in that cracks occur near the lower end portions 9, 9' of the side wall of the sub-side wall 3, particularly near 9. The discovered cracks are repaired and reinforced as appropriate, but even after repair 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 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 occurs due to the tendency to shift to the right in the figure (i.e. splitting phenomenon), and the tensile force that occurs based on the elongation difference due to the temperature difference between the furnace 1, the rear heat transfer section 2, and the sub-side wall 3. It is believed that cracks occur at the lower ends 9, 9' due to a complex relationship between shearing forces and the like.

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] The present invention provides a boiler in which a furnace and a rear heat transfer section are connected by a sub side wall, in which a part of a tube constituting the rear wall of the furnace is extended laterally and This boiler furnace wall is characterized in that a boundary between the side wall of the sub-side wall and the furnace is formed by an overhanging tube.

[Function] By forming the boundary between the side wall of the sub-side wall and the furnace using a part of the tube constituting the rear wall of the furnace, the temperature difference between the furnace and the boundary is eliminated, and the temperature difference becomes the cause. This prevents cracks from occurring at the lower end of the boundary portion.

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

FIG. 1 is a partially cut away and omitted three-dimensional view showing one embodiment of the present invention, and parts in the figure with the same reference numerals as in FIGS. 2 and 3 represent the same parts.

The side wall 12 of the furnace 1 has a structure in which a large number of evaporation tubes 13 are arranged in parallel, and the evaporation tubes 13 are connected by fins 14. Similarly, the rear wall 15 of the furnace 1 has a large number of evaporation tubes 16 arranged in a row. The evaporation tubes 16 are connected by fins 17. Further, the upper ends of the evaporation tubes 16 forming the rear wall 15 of the furnace 1 are extended directly upward every few to form riser tubes 18 that penetrate inside the boundary between the furnace 1 and the sub-side wall 3, and A nose pipe 19 extends obliquely upward and constitutes the inner bottom of the sub-side wall 3, and a riser pipe 18
and the remaining evaporation tube 1 that is not used as the nose tube 19
A part of the evaporation pipe 16' is extended laterally, and the boundary between the side wall of the sub-side wall 3 and the furnace 1 is formed by the evaporation pipe 16' and the fins (not shown).

The portion of the side wall of the sub-side wall 3 other than the boundary portion formed by the evaporator tube 16' is comprised of a number of heater tubes 20 rising from the inlet header 6 and fins 21 connecting the heater tubes 20. It consists of

Further, the lower surface of the sub-side wall 3 is formed into an arch shape.

Note that 22 is a side wall of the rear heat transfer section 2, and 23 is a front wall of the rear heat transfer section 2.

In the present invention, since the boundary between the side wall of the sub-side wall 3 and the furnace 1 is formed by the evaporation tube 16' that constitutes the rear wall 15 of the furnace 1, there is no temperature difference between the boundary and the furnace 1, and therefore This prevents the occurrence of cracks in the lower end 9 of the sub-side wall 3 due to the concentration of stress such as tensile force caused by the difference in elongation caused by the temperature difference.

At this time, a temperature difference will occur at the boundary between the evaporator tube 16' and the heater tube 20 near the center of the sub-side wall 3, but since the shape of the boundary is such that stress is difficult to concentrate, Cracks will not occur due to force, etc.

Furthermore, by making the lower surface of the sub-side wall 3 arch-shaped, the lower ends 9, 9' of the sub-side wall 3 have a shape that makes it difficult for stress to concentrate. Even when a force or the like is applied, it is possible to prevent the lower ends 9, 9' of the sub-side wall 3 from cracking.

Furthermore, if necessary, a structure similar to that of the previous 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.

Note that the boiler furnace wall of the present invention is not limited to the above-mentioned embodiment, and the distribution of the upper end portion of the evaporator tube forming the rear wall of the furnace to the riser pipe, nose pipe, sub-side wall, side wall, etc. It goes without saying that this is arbitrary and that various other changes may be made without departing from the gist of the present invention.

[Effect of the invention] As explained above, according to the boiler furnace wall of the invention, a part of the tube forming the rear wall of the furnace is extended laterally, and the boundary between the side wall of the sub-side wall and the furnace is As a result, there is no temperature difference between the boundary part and the furnace, and the generation of tensile force between the furnace and the sub-side wall due to the temperature difference is prevented, thereby preventing the occurrence of cracks 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 a partially broken and omitted three-dimensional view showing an embodiment of the present invention, FIG. 2 is an explanatory view of a conventional example, and FIG. 3 is a partially enlarged view of FIG. 2. In the figure, 1 is the furnace, 2 is the rear heat transfer section, 3 is the sub-side wall, 9, 9' is the lower end, 15 is the rear wall, 16, 1
6' is an evaporation pipe, 17 is a fin, 18 is a riser pipe,
19 is a nose tube, and 20 is a heater tube.

Claims (1)

[Scope of utility model registration request] In a boiler in which a furnace and a rear heat transfer section are connected by a sub-side wall, a part of a tube constituting the rear wall of the furnace is extended and overhangs laterally, and the overhanging tube is used to connect the side wall of the sub-side wall with the furnace. A boiler furnace wall characterized by forming a boundary part.