JPH0579908B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an insulating furnace wall in which inorganic fibers are formed into blocks and the blocks are used as a heat insulating material for the furnace wall.

[Conventional technology]

Ceramic fiber has been widely used as a heat insulating material for industrial furnaces due to its light weight, high heat resistance, and low thermal conductivity.

There are various products made from ceramic fibers, but sheet-like products such as blankets and felt are mainly used as insulation materials for industrial furnaces.

When blankets or felt are used as furnace wall insulation, they are usually stacked on heat-resistant metal pins pre-attached to the furnace casing and pierced until they reach an appropriate thickness, and then fixed with washers or nuts made of heat-resistant metal. Was. This method is commonly called layer lining.

However, in recent years, stack lining has been increasingly adopted in order to accommodate high-temperature furnaces and shorten construction time. For example, as shown in Figure 1A, this statu-clining refers to
A blanket made of inorganic fibers is cut in advance into strips of appropriate size to make strip-shaped blankets 1, and a large number of strip-shaped blankets 1 are arranged in a stacked state while being compressed, and a heat-resistant metal rod is inserted in the stacking direction. The heat-resistant metal rod 3 is supported by a support fitting 4 which is inserted through the metal rod 3 and fixed to the furnace casing by welding or the like.

On the other hand, this strip-shaped blanket is composed of a large number of single fibers arranged in a direction parallel to the sheet surface. This indicates that the single fibers are aligned in a plane perpendicular to the cut edge of the sheet. Therefore, it can be said that the single fibers are arranged in a plane perpendicular to the furnace casing 1.

Since the single fibers are arranged in a plane perpendicular to the furnace casing 1 in this way, when the strip-shaped blanket is compressed in the stacking direction, it can be easily compressed, and when the compressive force is released, it returns to its original state. It has the resilience to return to its original state. Therefore, when attaching the strip-shaped blankets to the furnace casing while stacking them, they are attached while being strongly compressed in the stacking direction so that the restoring force can be exerted even during hot use.
Therefore, even if the strip-shaped blankets undergo thermal contraction during use, gaps are unlikely to be formed between the joints 5 formed by the strip-shaped blankets due to the restoring force.
As described above, conventional stack lining has the characteristic that the joints 5 are difficult to open due to heat shrinkage. In other words, if the layers are attached while being strongly compressed in the stacking direction, the apparent thermal shrinkage in the stacking direction can be reduced.

However, the strip-shaped blanket has almost no resilience when compressed in a direction perpendicular to the cut. Moreover, the resistance to compression is so great that it is impossible to install while compressing.

For these reasons, restoring force cannot be expected in the direction perpendicular to the stacking direction, so joints 5
will open. In FIG. 1B, joint 5 corresponds to this. Furthermore, since the furnace wall had no restoring force, the dimension D in the thickness direction was greatly reduced due to hot thermal contraction. That is, it was not possible to reduce the apparent thermal shrinkage in the other two directions. As described above, in the conventional method, it was possible to apparently reduce thermal shrinkage in only one of the three-dimensional directions, but it was not possible to reduce it in other directions. As a result, heat enters the inside of the furnace wall through the opened joints 5, reducing the insulation effect, and the heat-resistant metal rod 3 is oxidized and worn out.
Eventually, this would lead to the collapse of the reactor wall.

[Problem that the invention seeks to solve]

The present invention solves the above-mentioned problems of the conventional products, and provides a method for manufacturing an inorganic fibrous block that has restoring force in all directions under hot conditions, and an insulating furnace wall using this inorganic fibrous block. The purpose is to

[Means for solving problems]

To achieve this objective, the present invention takes the following steps.

In the first step, bulk inorganic fibers are placed in a bag made of air-impermeable film.

The inorganic fibers are one or a mixture of two or more selected from ceramic fibers, alumina fibers, mullite fibers, zirconia fibers, and the like. The type may be appropriately selected depending on the required heat resistance. At this time, a binder such as phenol resin, latex, colloidal silica, etc. may be mixed in advance with the bulk inorganic fibers. The binder helps the thread hold its shape in later steps and gives the block strength and stiffness. In the case of organic binders, they burn and burn out during use at high temperatures, while inorganic fibers recover their resilience. When a binder is used in this way, an inorganic fiber block is produced with a hardness depending on the type of binder, but when not used, an inorganic fiber block with the highest flexibility is produced.

Bags made of air-impermeable film can be made of any flexible sheet that does not allow air to pass through, such as vinyl film, polyethylene film, latex film, paper, aluminum foil, etc., and the material is not restricted. Furthermore, when the mouth of this bag is sealed and the inside is evacuated to reduce the pressure, if the reduced pressure can be maintained even if some air enters, it can be used even if it has a small hole. That is, maintenance of reduced pressure is related to pumping speed.

In the second step, a thin tube is inserted into the mouth of a bag made of air-impermeable film, the bag mouth is closed, and air is evacuated through the thin tube to reduce the pressure inside the bag.

When the air inside the bag is evacuated and the pressure is reduced in this way, the bag receives pressure evenly from the atmosphere outside the bag and attempts to reduce its volume. Therefore, the inorganic fibers packed inside receive pressure from the atmosphere via the film. In other words, in the present invention, the film serves as a medium for transmitting pressure to the inorganic fibers. The magnitude of the pressure is perpendicular to the film surface, and the maximum pressure is 1 kilogram per square centimeter. This pressure compresses the inorganic fibers into a smaller shape similar to their initial shape, thereby increasing their density. Therefore, the density can be controlled by the degree of vacuum.

The inorganic fibers inside the compressed bag have elasticity, so if air is introduced into the bag, the bag has the ability to expand and return to its original size. are doing.

In the third step, the evenly compressed inorganic fibers are
Stitch the top of the bag with thread to fix its shape and create a large inorganic fiber block. At this time, it can also be deformed into any shape by sewing. This method can be carried out, for example, using a special sewing machine previously invented by the present inventor (Japanese Patent Application No. 19399/1983).
This sewing machine is capable of fixing the shape by sewing very thickly deposited inorganic fibers with threads such as cotton thread or nylon thread, and can be most preferably used in the present invention. If the sewing direction is only one direction, when the compressive force is released after sewing, there is a tendency for the material to expand slightly in the direction perpendicular to the sewing direction. However, this degree of expansion does not impair the effects of the present invention. The reason for the slight expansion is that the inorganic fibers are long, and because these long inorganic fibers are compressed while intertwined, it is thought that even if the thread is sewn from only one direction, the frictional force between the fibers will prevent expansion. . Sewing in two-dimensional or three-dimensional directions at right angles to each other increases the strength, and also has the advantage that it does not lose its shape even if it is later cut in any direction. If you do not have such a special sewing machine, you can also sew by hand. The large inorganic fibrous blocks thus produced are cut into small inorganic fibrous blocks.
In this case, if the item is sewn only from one direction, care must be taken to cut it in a place where the thread will not be cut, but when producing large blocks, the seams are fixed with adhesive to prevent the sewn thread from coming off. This does not apply if a method is used in combination.

Even if the small inorganic fiber block made by cutting a large inorganic fiber block is sewn in one direction, as long as the sewn thread does not come out, the thread will be sewn in the direction perpendicular to the sewing direction. It rarely expands. The reason is as mentioned above.

The large and small inorganic fiber blocks made in this way are compressed uniformly by the atmosphere, so when the threads are burnt out due to high temperatures during use, the inorganic fibers are removed by the threads. The repulsive force that was restrained by the compression becomes a restoring force and attempts to restore the size to the size before being compressed. Next, a method for attaching the large and small inorganic fiber blocks thus produced to a furnace casing to form an insulating furnace wall will be described.

The following methods are available for attaching these blocks to the furnace casing. The furnace casing here is the outer shell of the furnace, and is also used to support the blocks.
Refers to iron angle structures, H-steel structures, firebrick walls, castable refractories, etc., and is not necessarily limited to structures consisting only of surfaces.

(a) Method of indirectly attaching blocks to the furnace casing First, an inorganic fiber module is made by attaching the block to a substrate, and this inorganic fiber module is directly attached to the furnace casing.

According to this method, an inorganic fibrous module is first made with blocks attached to a substrate, and this inorganic fibrous module is attached directly to the furnace casing. In this method, the substrate serves as a support for the block, and can be an iron plate, punched metal, wire mesh, inorganic fiber board, etc.

There are three ways to support the block on this substrate. The first method is to pierce a block with a heat-resistant metal rod, and then support both ends of the passed-through heat-resistant metal rod on a board placed parallel to the heat-resistant metal rod via other supporting metal fittings.
In this case, the block is supported on the substrate by both a heat-resistant metal rod and a support fitting.

A second method is to make a large number of holes in the substrate (this operation is not necessary if the substrate is made of punched metal or wire mesh) and then bond and fix the substrate and the block with a heat-resistant adhesive. In this case, it is a heat resistant adhesive that supports the block to the substrate. Examples of heat-resistant adhesives include water glass and aluminum phosphate. Furthermore, although not adhesives, alumina cement, plaster, etc. can also be used for this purpose.

The third method is a case where the first method and the second method are used together. That is, this is a method in which a block is supported with an adhesive on a substrate with a large number of holes, and a heat-resistant metal rod and supporting metal fittings are used as in the first method.

(b) Direct attachment method to the furnace casing According to this method, the block is directly attached to the furnace casing without making an inorganic fiber module as explained in (a). There are also three methods for this method. These methods are the methods when the substrate is replaced with the furnace casing in the explanation of the two methods explained in (a).

[Effect]

The bulk inorganic fibers, mixed or unmixed with a binder, are placed in a bag made of flexible, air-impermeable film, and then the inside of the bag is depressurized to equalize the atmospheric pressure on the inorganic fibers inside the bag. The bulk inorganic fibers are compressed into large inorganic fibers that are compressed into a similar shape to the shape before decompression. It becomes a block. This block can be used as is or cut into pieces and attached directly or indirectly to the furnace casing to form an insulated furnace wall.

〔Effect of the invention〕

Since the insulated furnace wall according to the present invention is made by attaching an inorganic fiber block compressed with equal pressure in all directions to the furnace casing, it can be restored in all directions when used in hot conditions. It has a strong force and can be arranged so that the joints in any direction will not open even if heat shrinks. Therefore, there is no heat leakage from the joints, so you can use it with confidence. Furthermore, the dimension of the furnace wall in the thickness direction does not become smaller due to heat shrinkage. Therefore, the heat insulation effect does not deteriorate.

〔Example〕

Embodiments of the present invention will be explained with reference to FIGS.

Figure 2 A, B, and C are perspective views of the method for manufacturing large or small inorganic fiber blocks, and Figure 3 A,
B and C are cross-sectional views showing an insulated furnace wall made by attaching an inorganic fiber block to a furnace casing.

20 kg of ceramic fiber bulk was prepared as bulk inorganic fiber. Separately, a 600 x 600 x 1500 mm bag made of vinyl with a thickness of 0.05 mm was prepared. This bag was 600 x 600 mm with one side open. With the mouth of this bag facing up, the bulk fiber prepared earlier was added little by little and packed evenly so that the height from the bottom was 1000 mm. At this time, the bulk density inside the bag was 55Kg/m ³ . Next, put inside the bag with an inner diameter of 10 mm.
Insert one end of the plastic pipe and close the bag. I used vinyl adhesive to close the bag. Figure 2A shows what was completed in this way. In FIG. 2A, inorganic fibers (ceramic fiber bulk) 7 are evenly packed into a bag 6, and the opening of the bag is closed with a vinyl adhesive 8. One end of the vinyl pipe 9 is inserted into the bag.

Next, connect the vinyl pipe 9 to the vacuum pump,
The air inside the bag was sucked out. As a result, the bag gradually shrunk to two-thirds its original size in length, width, and height. In other words, it became a rectangular parallelepiped with dimensions of 400 x 400 x 630 mm. At this time, the density of the inorganic fiber (ceramic fiber bulk) inside the bag is approximately 200 kg/
It was ^m3 . In this way, the air inside the bag was suctioned and the bag was sewn with nylon thread from above to form a large inorganic fiber block. I used a special sewing machine with a long needle, and the pitch was 20 mm. The sewing direction was from one side of the 400 x 630 mm to the opposite side, and then the sewing direction was perpendicular to the previous sewing direction. At this time, liquid adhesive 10 was applied to the hole (stitch) into which the thread 11 inserted with the needle was introduced, and the binding point of the upper thread and lower thread at that position was fixed.

A large inorganic fibrous block made in this manner is shown in FIG. In step B, the bag 6 is sewn over the bag 6 with a thread 11, and the adhesive 10 is attached to the seam.
After sewing the vinyl pipe 9 with the thread 11, suction was stopped and the pipe was cut. At this time, since the shape of the block was fixed by the thread 11, no deformation occurred.

Figure 2 (c) is a 400 x 400 block obtained by cutting the large inorganic fiber block made in (b) along a plane parallel to the A-B cross section of (b).
It is a small inorganic fiber block of ××300 mm. A band saw was used for cutting.

Next, a heat insulating furnace wall made by attaching the inorganic fiber block thus made to the furnace casing will be explained.

FIG. 3A shows an adiabatic furnace wall in which an inorganic fibrous block 15 is processed into an inorganic fibrous module 13, and this inorganic fibrous module 13 is attached to a furnace casing 2 made of an iron plate. Inorganic fiber module 13 was made by the method described above.
A substrate 12 made of punched metal of 300 x 300 mm is adhered to one side of a small inorganic fiber module of 300 x 300 x 300 mm using heat-resistant adhesive 14, and two heat-resistant metal rods 3 are attached parallel to this substrate 12. It is inserted and both ends are caulked and fixed to the support fitting 4 which has been welded to the substrate 12 in advance. Attachment to the furnace casing 2 was performed by welding. Third
Figure B shows the case where the furnace casing 2 is made of castable refractory material, and is made of inorganic fiber block 15 of 300 x 300 x 50 mm.
This is an insulated furnace wall that is attached to the furnace casing 2 by applying heat-resistant adhesive 14 to the 300 x 300 mm surface of the furnace.

FIG. 3C shows an insulated furnace wall in which an inorganic fiber block 15 is directly attached to a furnace casing 2 made of an iron plate. A support fitting 4 with holes is attached to the furnace casing 2 by welding. Then 300x in place
While pressing an inorganic fiber block 15 of 300 x 300 mm, a heat-resistant metal rod 3 was inserted through a hole in a support fitting 4, and one end of the rod was inserted into a hole in another support fitting.

When the insulated furnace walls constructed in Figure 3 A, B, and C were all used at high temperatures, the joints did not open in any direction, and there was no decrease in the thickness of the furnace wall.

[Brief explanation of the drawing]

Figure 1A is a front view of a conventional adiabatic furnace wall, Figure 1B is a side view of a conventional adiabatic furnace wall, Figures 2A, B, and C are explanatory diagrams showing the method for manufacturing inorganic fiber blocks; Figures 3A, 3B and 3C are sectional views showing an insulated furnace wall in which inorganic fiber blocks are attached to the furnace casing. 2...Furnace casing, 3...Heat-resistant metal rod, 4
...Supporting metal fittings, 12 ... Board, 6 ... Bag, 8 ...
Vinyl adhesive, 13... Inorganic fiber module, 14... Heat resistant adhesive, 15... Inorganic fiber block.

Claims (1)

[Claims] 1. Bulk inorganic fibers are mixed with a binder or not mixed with a binder, and placed in a bag made of an air-impermeable film, and the pressure is reduced, so that the inorganic fibers in the bag are The bag is compressed using air pressure and sewn over the top of the bag to fix its shape to form a large inorganic fiber block, which is then cut and divided into smaller inorganic fiber blocks, or directly or indirectly attached to the furnace casing without being divided. An insulated furnace wall characterized by being attached to. 2. The adiabatic furnace wall according to claim 1, wherein the inorganic fiber is one or a mixture of two or more selected from ceramic fiber, alumina fiber, mullite fiber, and zirconia fiber.