JPH0788927B2 - Boiler equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace wall structure of a boiler device, and more particularly to a boiler device having a structure suitable for reducing stress at a toe of a furnace wall membrane bar.

<Prior Art and Problems Thereof> In the conventional apparatus, as shown in FIGS. 12 to 17, the relationship of the ceiling wall pipe 13 penetrating the furnace wall pipe is as shown in FIG. 13 and FIG. The distance from the ceiling wall tube 13 to the furnace wall membrane bar toe 10 was short. This is the minimum size that the ceiling wall tube 13 can penetrate, and the range of the membrane wall was expanded as much as possible to prevent the combustion gas of the furnace from flowing out into the penthouse.

However, in recent years, it has been required to provide a Benson boiler capable of variable voltage operation and a supercritical pressure boiler capable of daily start and stop (referred to as DSS). These are because when the boiler is started, a temperature difference occurs between the furnace wall tube 1 and the ceiling wall tube 13 due to the temperature change of the fluid at the time of water filling and load increase, and the expansion difference in the width direction of the boiler furnace accompanying this occurs. As a result, the furnace wall tube 1 and the ceiling wall tube 13 come into contact with each other, and bending stress is generated in the membrane bar toe part 10, which is subjected to repeated forces during the operation cycle at the time of start and stop, resulting in fatigue phenomenon. As shown in the detailed view, no consideration was given to the occurrence of cracks 21 in the wrap-around welded portion of the membrane bar toe portion 10 and to the leakage from the crack of the wall of the furnace wall tube 1.

The above-mentioned prior art does not consider the point that excessive bending stress is generated in the membrane bar toe portion 10 due to the difference in elongation in the furnace width direction, and there is a problem that cracks occur in the membrane bar toe portion 10. The solution was demanded.

<Object of the Invention> An object of the present invention is to propose a structure for reducing bending stress of the membrane bar toe portion 10 and preventing cracks.

<Summary of Means> The purpose is to increase the distance from the ceiling wall tube 13 to the membrane bar toe 10 so that the furnace wall tube 1 has flexibility and the membrane bar toe is welded to form a weld. This is achieved by rounding the metal to give it a smooth shape.

<Example> An example of the present invention will be described with reference to the drawings.

FIG. 4 shows the overall structure of the ceiling wall pipe 13 penetrating the furnace wall pipe 1. Next, in Figures 5 and 6, the furnace wall tube 1 and the ceiling wall tube are shown.
13 shows the arrangement and accessories.

With reference to FIG. 1, which is one example thereof, this figure shows the details of the grooved portion of the membrane bar in FIG. 5, and it is possible for the membrane bar 2 to be automatically welded to the furnace wall tube 1 in advance. A small hole (referred to as a drill hole 4) corresponding to the width of the membrane bar is provided on the lower side as far as possible, and the furnace wall tube 1 is drilled so as not to be damaged. Next, the membrane bar groove 3 is machined between the toe 10 of the initial membrane bar and the drill hole 4. The groove 3 has a cut width of about 3 mm to make the furnace wall tube 1 flexible and at the same time prevent castable from flowing into the furnace. Next, after the membrane bar grooving 3, the membrane bar toe 11 is subjected to build-up welding 5, and the furnace wall tube 1 to be immediately annealed and the weld metal are completely fused and melted. Further, the furnace wall tube 1 and the buildup weld toe portion 6 have a smooth R finish.

<Other Embodiments> Other embodiments of the present invention are shown in FIGS.

Details of grooving of the membrane bar of FIG. 10 are shown in FIGS. 7 to 9.

Referring to FIG. 7, a stop hole 20 is provided as low as possible between the ceiling wall pipe 13 and the steel 8 with the casing of the fitting portion casing, and a groove is cut between the initial membrane bar toe portion 10 and the stop hole 20. To process.

The effect of this embodiment is that the bending stress at the toe of the membrane bar can be reduced by a simple operation.

<Effect> By carrying out the present invention, the membrane bar after cutting the groove of the membrane bar becomes a finned tube, and the castable 17 and the far-influx 18 for preventing outflow into the furnace without extending the fin 16 shown in FIG. It can be used as a material.

Bending stress at the toe of the membrane bar is reduced, and it is possible to prevent cracks due to fatigue phenomena.

By bending the penthouse casing 9 and bringing the casing-attached steel 8 into close contact with the furnace wall tube, the temperature difference from the furnace wall can be reduced, and cracks due to thermal stress can be prevented.

Since the shape after cutting the groove of the membrane bar becomes the shape with fins, it is possible to omit the work step of manually installing a new fin in order to prevent castable and fair inflatables from flowing out into the furnace.

Since the toe of the new membrane bar is finished in a smooth shape with the weld metal, there is no accident phenomenon in which cracks occur due to minute defects due to poor fusion in the past.

By grooving the membrane bar, it is possible to reduce the bending stress applied to the membrane bar toe by increasing the dimension 1 from the point of action (ceiling wall pipe) to the membrane bar toe.

[Brief description of drawings]

FIG. 1 is a front view (detailed view) of a boiler furnace wall device according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a side sectional view of FIG. Fig. 4, Fig. 4 is a perspective view showing the entire structure, Fig. 5 is a detailed view of the ceiling wall pipe and the furnace wall pipe penetrating portion of Fig. 4, Fig. 6 is a side sectional view of Fig. 5, and Fig. 7 is FIG. 8 is a front view showing another embodiment, FIG. 8 is a sectional view taken along line BB, FIG. 9 is a side sectional view of FIG. 7, and FIG. 10 is a detailed view of a ceiling wall pipe and a furnace wall pipe penetrating portion. FIG. 11 is a side sectional view of FIG. 10, FIG. 12 is a perspective view showing the entire structure of a conventional boiler furnace wall device, and FIG. 13 is a detailed view of the ceiling wall pipe and the furnace wall pipe penetrating portion of FIG. 12, 14 is a side sectional view of FIG. 13, FIG. 15 is a detailed view of the membrane bar wall of FIG. 13,
16 is a sectional view taken along the line CC of FIG. 15, and FIG. 17 is a side sectional view of FIG. 1 ... Water pipe wall pipe, 2 ... Membrane bar 3 ... Groove, 4 ... Small hole 5 ... Build-up welding, 6 ... Lower edge of small hole 7 ... Filler plate 10 ... Toe

Claims (1)

[Claims] 1. A penthouse casing at a location where a ceiling pipe extending from a ceiling pipe header located inside a penthouse of a boiler penetrates a membrane panel, to a membrane bar of a water wall pipe located on the left and right of each ceiling pipe. The lower part and the membrane panel are connected via a filler plate, and a small hole having a width of the membrane bar is provided above and in the vicinity of the connection point, and overlay welding is performed on the lower edge of the small hole, A boiler device, characterized in that a groove is formed by a small width grooving process from the upper edge of the small hole to the upper end of the membrane bar.