JPH02203194A - Refractory construction of boiler water tube wall - Google Patents

Abstract

PURPOSE:To prevent the deterioration due to atmospheric gases, obtain a stable refractoriness and provide ease of repairing by putting a gap made of firebrick on the exposed tip of a stud bolt. CONSTITUTION:A panel 4 is attached at a position on a boiler water tube wall where a stud bolt 3 penetrates into a setting hole 6 of the panel 4. When attaching the panel 4, carbon silicate type mortar 7 is filled into clearances between the gas side face of the boiler water tube wall and the back face of the panel, and between adjacent panels. After that, a gasket 8 made of ceramics and a washer 9, for example, are put on the stud bolt 3 whose tip is projected inside a recessed part 5 of the panel 4, and a nut 10 is screwed on to attach the panel 4 firmly. Further, mortar is filled into the recessed part 5, and a cap 11 made of carbon silicate brick is put into the recessed part to protect the tip of the stud bolt 3 and the nut 10, so that a refractory construction is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is utilized in the technical field of boilers, and particularly relates to a fireproof structure of boiler water tube walls.

(Prior art) Conventionally, the fireproof structure of boiler water pipe walls was as shown in No. 6 of the attached drawing.
Figures (A) and (B) have a deep throat.

In the figure, boiler water pipes 51.5 are arranged in parallel rows.
L, ...... is fin 52+5 by welding
2+....... are connected to form the water tube wall. A stud 53 is attached to the wall of the water pipe on the side facing the gas, that is, inside the furnace, and a lining N54 is formed by pouring refractory castable to protect the water pipe.

(Problems to be Solved by the Invention) The fire-resistant structure of the conventional boiler water pipe wall as described above suffers from large temperature fluctuations in the furnace surrounded by the boiler water pipe wall, such as in a garbage incinerator, and various types of corrosion. Under usage conditions where large amounts of corrosive gases and dust are generated, ■ Foreign components such as various corrosive gases and dust may enter the lining layer made of refractory castable, creating a deteriorated layer or causing damage to the composite fibers. Due to thermal stress caused by temperature changes, the lining layer cracks and peels off, exposing the boiler water pipes in a short period of time and failing to function as a protective layer. It often disappears.

This phenomenon is caused by the following properties of refractory castables that are in direct contact with combustion gas. This is due to this. First of all, castable refractories (unfired refractories) have the property of developing strength by being sintered to the inside by heating after construction, that is, by the atmosphere in which they are used, but sintering occurs near the boiler water pipes due to the low temperature. The castable is unable to withstand the internal thermal stress caused by the expansion and contraction that occurs within the castable due to temperature changes within the furnace, and cracks occur. Second, castable refractories are constructed by adding an appropriate amount of water and kneading them, and are dehydrated by natural drying or forced drying after construction, but many pores remain in the refractories after the internal moisture is removed. The ventilation rate increases. Therefore, atmospheric gas enters into the pores and forms a degraded layer, which causes the material to collapse and crack. If dust is present in the above-mentioned atmospheric gas, it will generate reactants and cause similar problems. Thirdly, castables are subject to many conditions during construction, such as the amount of water added, temperature, etc.
Since it is greatly affected by the kneading time, etc., the quality after construction tends to vary.

The present invention solves these problems and provides fire resistance for boiler water pipe walls that is not affected by construction conditions, exhibits extremely stable fire resistance without deterioration due to atmospheric gases, and can be easily repaired. The purpose is to provide structure.

[Means to solve the problem]

According to the present invention, the above object is to connect fins to a boiler water pipe to form a water pipe wall, and to install a panel of refractory bricks between the surface of the panel and the gas-contacting surface of the water pipe wall. This is accomplished by filling mortar between the end faces of adjacent panels, attaching them to the water pipe wall using stud bolts, and capping the exposed tips of the stud bolts with firebrick caps.

[Effect]

In the present invention as described above, direct contact with the combustion gas during use is made by a panel made of bricks having excellent fire resistance. Compared to conventional refractory castables, this panel is stronger (and has a smaller porosity, so the influence of various gases entering is small.Furthermore, it has a high thermal conductivity, so the temperature gradient inside the refractory is reduced. It is smaller and has less thermal distortion.Moreover, since the above-mentioned panel is in close contact with the boiler water pipe wall through mortar, the thermal conductivity to the boiler water pipe is increased.

Further, when repairing, only the panel that needs to be repaired can be removed from the stud bolt after the cap is removed. Therefore, not only is the work easy, but only the necessary parts can be repaired without affecting the surrounding area.

〔Example〕

Hereinafter, the present invention will be described in detail based on FIGS. 1 to 5 of the accompanying drawings.

First, prior to describing each embodiment, the advantages of refractory bricks, such as silicon carbide panels, will be described in comparison with conventional silicon carbide refractory castables.

■ Press molding at the manufacturing stage (approximately 500 to 800 kg/
cm'') is then heated and fired, and its quality is more stable than that of refractory castable that is not pressurized and is sintered during use at the construction site.

■ The above firing temperature is 300 to 500 degrees higher than the working temperature of bricks.
Because it is made at a high temperature of °C, there is no expansion or contraction when reheated at the operating temperature.

■ It has great strength because it is a fired product. For example, 100
The hot bending strength at 0°C is about 80 kg/am for fireproof castable, while the above panel has a hot bending strength of 4.
About 50 kg/cm" can be obtained.

■ Low porosity and high resistance to the penetration of various gases. The porosity of the above panel is about 11%, compared to 20% or more for refractory castable.

■ High thermal conductivity, small temperature gradient inside the refractory, and less thermal strain. The thermal conductivity of the above panel is 14 kcal/mh''C at 1000°C, while that of the refractory castable is 8 kcal/mh''C.

In the first embodiment shown in FIGS. 1 (^) to C), l are rows of boiler water pipes arranged in parallel. These boiler water pipes 1.1 are connected by welded fins 2 to form the boiler water pipe wall. A stud bolt 3 is attached to the fin 2 by welding toward the gas-contacting surface, that is, toward the inside of the furnace.

On the other hand, reference numeral 4 denotes a panel made of silicon carbide brick, which is manufactured by the above-mentioned manufacturing method and has the above-mentioned advantages, and has a substantially square planar shape as shown in the figure. The cross-sectional shape is such that the negative side is substantially flat and the other side forms a semicircular groove substantially corresponding to the shape of the boiler water tube wall. The panel has a recess 5 at the center of the negative side, and a mounting hole 6 formed therein.

The panel 4 is attached to the boiler water tube wall at a position where the stud bolt 3 passes through the attachment hole 6 of the panel 4. During this installation, silicon carbide mortar 7 is filled between the gas contact side surface of the boiler water tube wall and the other surface of the panel and between the end surfaces of adjacent panels as shown. Thereafter, for example, a ceramic packing plate 8 and a washer 9 are sequentially arranged on the head of the stud bolt 3 protruding into the recess 5 of the panel 4, and the panel 4 is firmly attached by tightening with a nut 10. Further, in order to protect the head of the stud bolt 3 and the nut 10, the recess 5 is filled with the mortar and a cap 1 made of silicon carbide brick is filled in the recess 5.
1, the fireproof structure of this example is obtained.

As described above, in this example, the panel made of silicon carbide bricks, which has excellent fire resistance, strength, and thermal conductivity, and has low porosity, forms the entire gas contact surface, so it is resistant to temperature changes. There is little embrittlement due to gas intrusion, and the internal temperature gradient is small, so the influence of internal thermal stress is also small (in addition,
The gaps between adjacent panels are filled with mortar to completely prevent gas from passing through.

Further, when repairing, only the panel that requires repair can be replaced with a new panel by removing the cap 11, nut 10, etc., and then removing that panel.

Therefore, there is no damage to adjacent panels that do not require repair.

Next, in the second embodiment shown in FIG. 2, the panel 4^ is flat on both sides, making it easier to manufacture the panel than in the first embodiment. Then, the space where the surface of the boiler water pipe wall and the surface of the panel do not match is filled with mortar 7A.

In the panel 4B shown in the third embodiment of FIG. 3, the end face of the panel shown in FIG. 1 is provided with a stepped portion in the form of an inro, so that the effect of preventing gas passage is enhanced.

Furthermore, in the fourth embodiment shown in FIG. 4, the panel 4C is fixed by stud bolts 3C at the corners, for example, at the four corners if the plane is rectangular. Therefore, in contrast to the case of the first embodiment shown in FIG. 1, where the tightening force is concentrated in the center, the tightening force can be distributed.

In the fifth embodiment shown in FIG.
protected. Therefore, there is no need to make the camp out of firebrick as in the previous embodiment, and the number of parts is reduced.

Note that in all of the embodiments described above, it is desirable that the panel be formed as thin as possible as long as strength and other requirements are met. Further, in the embodiments, the panels and caps are made of silicon carbide, but they are not limited to this, and other materials may be used as long as the refractory bricks have the same function.

〔Effect of the invention〕.

According to the present invention as described above, the following effects are obtained.

- The fireproof lining is made of silicon carbide and is closely attached to the boiler water pipe, increasing thermal conductivity, reducing thermal distortion and reliably preventing the occurrence of peeling and falling.

■ It is possible to prevent bolt damage by taking protective measures for the panel support.

■ Against bending, twisting, etc. due to thermal deformation of the furnace wall, it is possible to maintain the wall stably by dispersing and absorbing the distortion with small blocks by making it into panels.

■ By bonding the panel bricks with mortar, the panels and boiler water pipes are brought into close contact, smoothing heat transfer and preventing gas passage.Furthermore, the relative thermal expansion of the panels and boiler water pipes due to heating and cooling, It acts as a buffer against shrinkage and prevents panel bricks from cracking.

■ Through the above steps ■ to ■, it is possible to protect boiler water pipes with a longer lifespan than before.

[Brief explanation of the drawing]

Figures 1 (A) to (C) show a first embodiment of the present invention, with Figure 1 (A) being a sectional view taken in a plane perpendicular to the boiler water pipe, and Figure 1 (B) being the side of the boiler room. Plan view from above, Figure 1 (C)
2 is a sectional view taken in a plane parallel to the boiler water pipe, FIG. 2 is a sectional view taken in a plane perpendicular to the boiler water pipe of the second embodiment, and FIG. 4 is a cross-sectional view taken in a plane perpendicular to the boiler water pipe of the fourth embodiment, and FIGS. 5A to 5C are cross-sectional views of the fifth embodiment of the present invention.
Figure (A) is a cross-sectional view perpendicular to the boiler water pipe, Figure 5C
B) is a plan view as seen from the boiler room side, Fig. 5 (C) is a cross-sectional view in a plane parallel to the boiler water tube, Fig. 6 (^) is a plan view of a conventional fireproof structure as seen from outside the boiler room, and Fig. Figure 6 (B)
is a sectional view of the one shown in FIG. 6(^).

Claims (1)

[Claims] A water pipe wall is formed by connecting fins to a boiler water pipe, and a panel made of refractory brick is installed between the surface of the panel and the gas contact side surface of the water pipe wall and the end face of the adjacent panel. A fireproof structure for a boiler water pipe wall, which is attached to the water pipe wall using stud bolts with mortar filled between the holes, and a cap made of firebrick is attached to the exposed tip of the stud bolt.