JPH0585802B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a furnace bottom structure of a boiler having a furnace in which an evaporation tube constituting a furnace wall rises in a spiral manner (hereinafter referred to as a "spiral furnace"). It is related to.

[Conventional technology]

There are two types of conventional spiral furnace bottoms: an inclined bottom, in which the slope α of the peripheral wall and the bottom angle α are the same, as shown in FIGS. 1 and 2, and a flat bottom, as shown in FIGS. 3 to 6.

(Problem to be solved by the invention) Inclined bottom is The height of the furnace becomes higher due to the bottom of the furnace, making it uneconomical.

There are disadvantages such as a large imbalance in tube length in the furnace. On the other hand, flat bottoms do not have these drawbacks, but there is a problem with drainage when washing the inside of the furnace. If we add an inclined bottom shape of 2 to 3 degrees to the current flat bottom to discharge washing water (drainage) from the furnace, there will be parts where canned water in the furnace bottom tube cannot drain out when the boiler is shut down. It's inconvenient. Therefore, we aimed to solve these inconveniences.

[Means to solve the problem]

The present invention was made in consideration of steam, and in a boiler having a spiral furnace, the line where the nozzle header exiting the furnace inlet header and the furnace bottom are in contact is located at a lower position than the line where the furnace bottom and the furnace peripheral wall are in contact. The furnace bottom shape is composed of a plurality of planes, and the evaporation tubes connected by plate-like members forming the furnace bottom plane are bent downward at least at the boundary line between adjacent planes to form a spiral shape. The present invention provides a furnace bottom structure, characterized in that a discharge hole is arranged in a line where the furnace bottom is connected to the nozzle stub that is piped and comes out of the furnace inlet header.

[Effect]

By configuring the furnace bottom as described above, drain water during furnace flushing can collect at the lowest position along the slope of the furnace bottom and be discharged from the discharge hole, and canned water in the pipes that make up the furnace bottom can also be collected at the lowest position along the slope of the furnace bottom. Easily discharged when the boiler is stopped.

〔Example〕

Hereinafter, a first embodiment of the present invention will be described based on FIGS. 7 to 10.

This example shows a gentle V having a drain draft according to the present invention in the case of a furnace having a rectangular cross-sectional shape.
There are basically four planes that form the valley shape of the letter a.
-ed, a-d-c-b, b-c-f and a-
The hearth structure consisting of b-fe is shown. In the figure, the line where the nozzle holder 2 coming out of the furnace inlet header 1 touches the furnace bottom 3 is designated as a-b. Further, the line where the furnace bottom 3 and the furnace peripheral wall 4 are in contact is designated as c-d-e-f. a-b c-d
Place it at a level 200 to 300 mm below -e-f-c,
At the boundary line a-d where plane a-e-d and plane a-d-c-b are adjacent, the furnace bottom tube, which is the evaporation tube, bends downward, toward the lower part a-b. It's stiff. In this embodiment, line a-c is not necessarily a boundary line between two planes, but there is no problem even if the line a-c is bent so that the entire furnace bottom tube is piped in a spiral shape. With such a furnace bottom structure, the tube axis of the furnace bottom tube 5 always slopes downward from the furnace peripheral wall 4 to the nozzle stand 2 in the tube arrangement shown in the figure. For this reason, the drain during furnace flushing passes over the fin 6 and is collected in the line a-b, and by providing a drain discharge hole in this area, it can be easily discharged to the outside of the boiler. Further, when the boiler is stopped, canned water in the furnace bottom tube 5 is also easily discharged to the furnace inlet header 1 for the same reason.

Next, a second embodiment of the present invention will be described based on FIGS. 11 to 14.

This example shows a furnace bottom structure with a drain draft according to the invention for a furnace with a substantially square cross-sectional shape. In the figure, the line where the nozzle stub 8 coming out from the furnace front/rear wall inlet header 7 touches the furnace bottom 9 is designated as gh. The line where the nozzle heads 12 and 13 coming out of the furnace side wall inlet headers 10 and 11 touch the furnace bottom 9 is i-g-j,k.
-hi. Further, the line where the furnace bottom 9 and the furnace peripheral wall 14 are in contact is designated as m-n-o-pm. i-k,j
-i is placed at a level 100 to 150 mm below m-n-o-p-m, and g-h is placed below i-k, ji-i.
Place it at a level 100 to 150 mm below, and at the boundary line between the planes that make up the hearth bottom 9, for example the line i-m section, move the hearth tube from the nm side of the furnace wall to the lower b-h side. Fold.

With such a furnace bottom structure, the tube axis of the furnace bottom tube 15 always slopes downward from the furnace peripheral wall 14 toward the nozzle stands 8, 12, and 13 in the tube arrangement shown in the figure. For this reason, the drain when washing the furnace with water is Fin 1.
6 and is collected in the line gh, and can be easily discharged to the outside of the boiler by installing a drain hole in this area. Also, when the boiler is stopped, the furnace bottom tube 1
For the same reason, the canned water in the furnace 5 can be easily removed from the furnace front and rear wall inlet headers 7 and the furnace side wall inlet headers 10 and 11.
is discharged.

〔Effect of the invention〕

As described above, according to the present invention, it is easy to drain the drain during furnace flushing, and at the same time, it is also easy to discharge the canned water in the furnace bottom tube when the boiler is stopped.

[Brief explanation of the drawing]

Figure 1 is a side view showing the inclined bottom.
Figure 2 is a view taken along arrow A-A in Figure 1, Figure 3 is a side view showing the 8-corner flat bottom, and Figure 4 is the 3rd corner view.
5 is a side view showing a four-corner flat bottom, FIG. 6 is a view taken along C-C in FIG. 5, and FIG. 7 is a view showing the first embodiment of the present invention. Side view, Fig. 8 is a view taken along the D-D arrow in Fig. 7, Fig. 9 is a view taken along the E-E arrow in Fig. 7, and Fig. 10 is a view taken along the F-F arrow in Fig. 8. 11 is a side view showing the second embodiment of the present invention, FIG. 12 is a view taken along the line GG in FIG. 11, FIG. 13 is a view taken along the line H-H in FIG. 12, and FIG.
The figure is a view taken along the line II in FIG. 12. 1... Furnace inlet header, 2, 8, 12, 13...
...Tube stand, 3, 9... Hearth bottom, 4, 14... Furnace peripheral wall, 5, 15... Hearth bottom tube, 6, 16... Fin,
7... Furnace front/rear wall inlet header, 10, 11...
Furnace surrounding wall inlet pipe header.

Claims (1)

[Claims] 1. In a boiler with a spiral furnace, the shape of the furnace bottom is formed on multiple planes so that the line where the nozzle header exiting the furnace inlet header and the furnace bottom are in contact is at a lower position than the line where the furnace bottom and the furnace peripheral wall are in contact. evaporation tubes connected by plate-like members forming the furnace bottom plane at least at the boundary line between adjacent planes are arranged in a spiral shape so as to bend downward, and exit the furnace inlet header. A hearth bottom structure characterized in that a drainage hole is arranged in a line where a nozzle stand and the hearth bottom contact each other.