JPS596193B2 - Lining method by spraying monolithic refractory material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for furnace lining by spraying monolithic refractory material.

There are many examples of furnace lining construction by spraying castable refractory materials, etc., and some industrially implemented methods have been developed, but in the case of special furnaces, there are various special conditions. implementation is restricted.
For example, in the case of lining the lateral inner surface of a furnace such as a tundish, where the depth cannot be adjusted, spraying cannot be performed, and core coating is actually performed by hand. In other words, in the case of spray lining for a tundish, a completely dry method (powder and water are sprayed separately from a nozzle and mixed in front of the wall to form the lining) is possible, but Although this dry method is not limited to the case of tundish, it is generally undesirable in terms of pollution since it generates a large amount of dust.

On the other hand, the wet method (in which water and refractory material are mixed in advance and sprayed through the pipe using a pressure pump) is a method in which the refractory material and water are mixed in advance and sprayed inside the feed pipe or nozzle. Not only does the material harden, making continuous work difficult, but
The capacity of the pressure pump must be increased, and for example, in the case of lining a tundish, several tundishes are often used intermittently, and there are great concerns about hardening and clogging in the mixer and hoses, making it even more difficult to adopt a wet method. Have difficulty. The present invention has been developed as a result of various researches to solve all of these problems and to enable continuous spraying of superior lining for furnaces that require special conditions such as tundishing. This was discovered by making various improvements to the method, position, nozzle shape, etc. That is, the present invention separately feeds a specific amount of water to the powdery refractory material, mixes them in the feed nozzle of the spraying device, and then mixes this mixture at a rate of 30 to 750 (1 ) The gist of this lining method is to spray a monolithic refractory material onto a predetermined wall after the material passes through a nozzle portion having a bending portion that changes the direction within a certain range.

The present invention will be described below with partial reference to the drawings.

The present invention enables mechanical work using a spray gun to line tundishes, whereas conventional lining was done with a trowel. The dry type was chosen because the purpose could not be achieved due to the difficulty of work due to clogging, etc., and the durability of the lining after construction due to restrictions such as the proportion of water in the mixture. On the other hand, in order to eliminate the problem of dust generation due to the dry method, it is necessary that water and refractory material are already mixed when they come out of the spray nozzle. In contrast, the water is fed separately and mixed in the feed nozzle of the spray device. That is, to explain a typical example of the present invention with reference to the drawings, water and refractory material are supplied separately without being mixed in advance, for example, water is supplied from the water supply pipe 1, and refractory material is supplied from the refractory material supply pipe 1. It is fed from the feed nozzle 2 and mixed in the feed nozzle 3 of the spraying device.

The mixture is sprayed onto a predetermined wall surface from the tip of the nozzle through the feeding pipe 4 of the feeding nozzle, but in the present invention, the feeding direction of the mixture is changed midway through. That is, a mixture having a predetermined water content, which will be described later, is then passed through a feed pipe in a feed nozzle provided with a bending portion 5. In the present invention, the direction of the mixture must be within a range where the degree of direction θ with respect to the feeding direction is 30 to 75 degrees. The effect of changing the feeding direction is that the water and mixture can be sufficiently mixed with the simple means of changing the direction and in a short contact range, and that the vertical spraying to the wall surface can be made more effective by reducing rebound loss. The purpose is to make it easier to install, and to facilitate construction in narrow areas.
It is best to set θ to at least 3. Conversely, if the angle is bent beyond 75°, the mixture of water and refractory material will be spewed out from the tip of the spray device intermittently in clumps, resulting in a uniform and uneven distribution. I can't do lining. In addition, the optimal turning angle is 45 to 65
? be. The mixture that has passed through the bending section is discharged from the discharge pipe 6.
In this case, it is preferable to spray perpendicularly to the wall surface in order to improve lining efficiency (less rebound loss, etc.) and form a desirable lining, but the method of the present invention This is easier because the distance between the outlet and the outlet may be narrower. As mentioned above, the method of the present invention is suitable for vertical spraying onto walls (especially side walls) of tundishes with small working spaces. One of these is adjusting to
For this purpose, the amount of moisture must be between 5 and 5 in the content of powdered refractory material.
20% into the feed nozzle of the spraying device.

That is, when spraying is carried out on the lower surface using the method of the present invention, there is not much difference in the difficulty of spraying, the occurrence of sagging, or the spraying loss due to changes in the amount of water, but when spraying on the side wall surface. This is important when spraying, and in this case, specifically, if the amount of water is too small, there will be a lot of spraying loss, and the moisture may be uneven and dust may be generated intermittently.
On the other hand, it has been found that if the amount of water is too large, the discharge becomes intermittent and there is a lot of sloshing, and concavities are likely to occur on the sprayed surface, making it difficult to obtain a desired lining. In the present invention, water may be supplied in a specific part of the feed nozzle so as to be mixed with the refractory material, but it is of course also possible to supply a portion of this water in two or more stages. For example, as shown in FIG. 1, the mixture once mixed in the feed nozzle 3 passes through the feed pipe 4 from a feed pipe 8 provided by extending the feed pipe 1 of a part of the water. It may also be supplied additionally by opening valve r at the position. Even in such a case, it is desirable that additional water be supplied to the refractory material before the mixture reaches the diversion section 5 in the pipe, and the amount of this additional supply should be 30% of the amount of water used. It is best to keep it below. On the other hand, in the present invention, the mixing of water and refractory material is
The purpose can be achieved even if a small portion of water is mixed with the refractory material before each supply, but the proportion is preferably less than 20% of the amount of water used, especially less than 10%. In any case, no such pre-mixing is necessary.

The apparatus for achieving such a method of the present invention includes a water supply pipe 1, a granular refractory material supply pipe 2, and a supply system that connects these and simultaneously supplies water and refractory material in a mixed manner. In the device equipped with an amorphous refractory material spraying device consisting of a nozzle 3 and the water and refractory material pumping devices 9 and 10, the feeding nozzle further has a diameter of 30 to 75 b in the feeding direction.
An elbow-type bending portion 5 is formed to bend the nozzle within a range.

The present invention, even though it is a dry type, generates no dust at all, enables work in narrow spaces, and makes it possible to continuously perform lining with sufficient durability by mechanical means. Its industrial value is enormous.

Aspects according to the invention will be further described below with reference to specific examples.

The basic composition of castable is 70 to 90 parts by weight of refractory aggregate, 5 to 25 parts by weight of alumina cement, and 10% or less of clay added as needed, and the maximum particle size is 1.68W1n12.4? The lining was applied to the wall using the equipment shown under the following operating conditions:

)-11+''yo = 5V Crystal - Chang- ('& Crystal Todoroki Crystal) A general explanation of these results is as follows. (
1) All rebound loss including moisture is about 10%.

(2) Regarding the amount of clay, there is almost no difference in the spraying work situation, but if it becomes 10%, it will not be completely emitted from the tip and a large amount will fall off, so 5% or less is good and around 2% is optimal.

(3) Maximum particle size of aggregate Although it is better to have a finer grain size (1.68wn), there is no problem with 2.4wn.

(4) There is no need to increase the amount of moisture, there is little variation after construction, and it is easy to control the lining to about 10-12%, and dust generation increases when it is less than 5%.

(5) High pressure seems to be good from the quality point of view of the pneumatic lining, but high pressure is not suitable for spraying even if the distance from the discharge end to the wall is less than 10 m, and on the other hand, if it is too low, the discharge will be messy. Approximately 1.8 to 3.5 Ki is good.

(6) Cracks on the lining surface Very little compared to troweled products.

(7) Is the degree of bending of the elbow type joint 90? 304 due to increased sagging and improper lining.
The following conditions are unsuitable: uneven moisture, intermittent dust generation, and uneven lining surfaces.

[Brief explanation of drawings]

The drawing is a schematic diagram showing the configuration of an apparatus for explaining a typical example of the present invention. In the drawing, 1 is a water supply pipe, 2 is a refractory material supply pipe,
3 is a mixture feeding nozzle, 4 is a mixture feeding pipe, 5 is a bent portion, and 6 is a tip pipe portion.

Claims (1)

[Claims] 1. Water is separately fed to the powdery refractory material and mixed in the feed nozzle of a spraying device, so that the amount of water relative to the powdery refractory material is 5% by weight of the total amount. -20% mixture is then passed through the nozzle part equipped with a bending part that changes the direction within a range of 30 to 75 degrees with respect to the feeding direction, and then is sprayed from the nozzle onto a predetermined wall. Lining method by spraying shaped refractory material. 2. The lining method according to claim 1, wherein the deflection angle is in the range of 45 to 65 degrees. 3.Additionally adding a small portion of water to the mixture of water and granular refractory material in the feed nozzle before deflection
Lining method described in section.