JPH046906Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a breathable heat insulating material used to insulate an exhaust port of a heating furnace.

Conventional technology and its problems Conventionally, a ceramic honeycomb structure formed by connecting a large number of fine hexagonal cylindrical cells in a row at the exhaust port of a heating furnace, or a ceramic honeycomb structure formed by connecting a large number of fine-mesh hexagonal cylindrical cells in a row, or a ceramic honeycomb structure formed by connecting a number of fine hexagonal cylindrical cells in a row in a substantially diagonal figure-8 shape has been used. Ceramic porous bodies with a wall-like structure formed by connecting a large number of cylindrical cells, ceramic roll core structures formed by connecting a large number of pairs of cylindrical cells, ceramic foam, etc. A porous ceramic body with a three-dimensional network structure that allows the fluid to flow while repeatedly colliding with the grid as it passes through the interior is installed as an air permeable heat insulating material, allowing the fluid to flow from the heating furnace. By blocking the radiation cooling of the exhaust gas, and by exchanging heat energy of the exhaust gas as it passes through the breathable insulation material and radiating it to the heating side as radiant heat from the breathable insulation material, the exhaust gas is It has been proposed to directly reuse the thermal energy of
page” etc.).

However, when porous ceramic bodies are used for this type of application, a temperature difference of several hundred degrees Celsius may occur between the upstream and downstream sides of the porous ceramic body through which the fluid passes, and this is due to the large thermal stress. There was a problem that the ceramic porous body was damaged. In this case, especially when the honeycomb structure is used under conditions where a sudden temperature change occurs, cracks occur from the corners and the honeycomb structure is easily damaged.

Means for solving the problem and its effect The present invention was made in view of the above circumstances,
In order to provide a breathable heat insulating material that is easily damaged by thermal stress even when used in applications where large thermal stress is generated, the above-mentioned ceramic porous body having a wall-like structure consisting of a large number of cylindrical cells connected in series is used. A hollow portion is formed in the wall constituting the cylindrical cell, and one axial end thereof is open to the outside, and a non-linear A ceramic porous body with a three-dimensional network structure having a three-dimensional internal communication space, that is, a three-dimensional network-like lattice structure, in which the fluid flows while repeatedly colliding with the lattice as it passes through the interior. It is a layered structure.

That is, in the breathable heat insulating material of the present invention, the ceramic porous body with the above-mentioned wall-like structure is normally used on the high-temperature upstream side, and the network-structured porous ceramic body is used on the low-temperature downstream side. By forming a hollow part that is open at one end (upstream side) in the axial direction in the wall constituting the cylindrical cell of the ceramic porous body having a shaped structure, the ceramic porous body is made more likely to deform due to heat, This reduces the thermal stress generated due to temperature differences within the porous body of the wall-like structure, and furthermore, by adopting the above-mentioned two-layer structure, the thermal stress generated in the ceramic porous body of the wall-like structure on the upstream side is reduced. This prevents thermal stress from being directly transmitted to the ceramic porous body with a network structure on the downstream side, thereby reducing thermal stress and preventing damage.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Embodiment FIG. 1 shows an embodiment of the present invention, in which the breathable heat insulating material 1 is made of a first ceramic porous body having a wall-like structure having a honeycomb structure in which a large number of hexagonal cylindrical cells 2 are arranged in series. A hollow portion 5 is formed in the wall 4 constituting the cylindrical cell 2 of No. 3, and one axial end thereof is open to the outside, and the other axial end surface of the first ceramic porous body 3 (the hollow portion 5 The non-open side surface has a three-dimensional network structure with a non-linear internal communication space, that is, a three-dimensional network lattice structure, and as the fluid passes through the interior, the fluid repeatedly collides with the lattice. This is a stack of plate-shaped second ceramic porous bodies 6 having a fluidized network structure.

FIG. 2 shows another embodiment of the present invention, in which the breathable heat insulating material 1 has a large number of paired circular cylindrical cells 2, 2' arranged in a substantially diagonal figure 8 shape. A hollow portion 5 is provided in the wall 4 constituting the cylindrical cells 2, 2' of the first ceramic porous body 3 having a wall-like structure and having a continuous roll core structure. At the same time, a second ceramic porous body 6 having a network structure similar to that shown in FIG. This is what I did.

In this case, the hollow portion 5 of the first ceramic porous body 3 having the wall-like structure is formed by the wall 4 of each cylindrical cell 2, 2'.
The hollow portions 5 formed within the wall 4 of the cylindrical cells 2, 2' along the circumferential direction of the wall 4 are continuous with each other. Also,
As shown in FIG. 3, the hollow portion 5 is formed in the wall 4 in a continuous state along the axial direction from one end surface of the wall 4 to the vicinity of the other end surface. Therefore, as a result, the wall body 4 of the cylindrical cell 2 has two parts along its thickness direction.
divided into two dividing walls 4 at the other end.
a, 4a are integrally connected, and both dividing walls 4a, 4a are mutually free at one end, so that it is easy to move in the thickness direction on the one end side and easily cause thermal deformation. It is formed.

First ceramic porous body 3 of each embodiment described above
In a ceramic porous body having a honeycomb structure or a roll core structure, a hollow part 5 is formed in the wall body 4 constituting the cylindrical cell 2, and one end in the axial direction thereof is open to the outside.
is formed, and as a result, each cylindrical cell 2 is formed in such a state that its wall body 4 is divided into two parts, as described above, and especially on one end side, these two dividing walls 4a, 4a are mutually separated. Since it is in a free state, easily moves in the thickness direction, and is easily deformed by heat, the first ceramic porous body 3 is subjected to a large temperature difference due to temperature rise and fall, and even if a considerable thermal shock occurs, thermal stress is not caused. very well dispersed and therefore the first ceramic porous body 3
shall not be easily damaged by thermal stress.

Note that the shape of the first porous body with the wall structure according to the ceramic of the present invention and the cylindrical cells constituting it are not limited to the above embodiments, and may have any shape in which a large number of cylindrical cells are arranged in series. Can be adopted. For example, the cylindrical cell can be modified in various ways, such as being formed into a polygonal cylindrical shape such as an octagonal cylindrical shape instead of a hexagonal cylindrical shape, or formed into an elliptical cylindrical shape instead of a cylindrical shape. A ceramic porous body with a honeycomb structure in which a large number of polygonal cylinders are arranged in a row and a ceramic porous body in a roll core structure in which a large number of cylindrical or elliptical cylindrical cells are arranged in a row are suitable, and in particular, the latter roll core structure has no corners, This is effective because stress is difficult to concentrate. Further, the cylindrical cell may be formed in an inclined state if necessary. Here, the first ceramic porous body 3 has a width d (diameter in the case of a cylindrical cell, or a short axis in the case of an elliptical cylindrical cell) of the cylindrical cells 2, 2' of 5 to 30 mm, and a height ( First ceramic porous body 3
thickness) h is 10 to 100 mm, and if the cylindrical cells 2, 2' are formed in an inclined state, the inclination angle θ is 20°.
It is preferable to set the angle to ~70°.This suppresses the increase in pressure loss and combustion inhibition due to clogging caused by the accumulation of dust in the exhaust gas, effectively blocks radiation cooling, and improves thermal shock resistance and strength. A large amount of breathable insulation is obtained. On the other hand, if the width d is smaller than 5 mm, the pressure loss will be high, and the dust in the exhaust gas will accumulate in the passage (cavity 7) and easily cause clogging, so the pressure loss will be relatively short. This is inappropriate because it increases with use over time, and if it exceeds 30 mm, the porosity increases, and the surface area of the ceramic wall that should exchange heat with the exhaust gas becomes relatively small, making it difficult for the exhaust gas to pass into the insulation material. Since heat transfer is reduced and radiation cooling is increased, it is unsuitable for use in the breathable insulation material of the present invention. Furthermore, if the height (h) of the cylindrical cells 2, 2' (thickness of the ceramic porous body 3) is smaller than 10 mm, the surface area of the ceramic wall will become smaller, and heat transfer from the exhaust gas to the heat insulating material will decrease, resulting in poor performance. appropriate and also
If it exceeds 100 mm, it is unsuitable because it increases air resistance and tends to cause dust clogging. The preferred range for the width d is 7 to 18 mm, and the preferred range for the height h is 15 to 30 mm.

In addition, in the present invention, the shape of the hollow portion formed in the wall of the cylindrical cell is not limited to the above embodiment, but as shown in FIG. Moreover, it is preferable to form the wall from one end surface to the vicinity of the other end surface. In this case, the thickness of the hollow part is preferably 1/10 to 1/2 the thickness of the wall, and the depth of the hollow part is preferably 9/10 to 3/10 of the height of the wall. preferable.

Further, as the second ceramic porous body 6 having a network structure used in the breathable heat insulating material of the present invention,
A three-dimensional network skeletal structure with a non-linear internal communication space obtained by sintering a ceramic slurry attached to a soft polyurethane foam without a cell membrane as described in Publication No. 58-32090. Ceramic foam having the same shape as the polyurethane foam can be suitably used. In this case, the bulk specific gravity of the ceramic foam is 0.25~
0.7, and the average diameter of the internal communication space is 0.2~10mm
It is preferable that the porosity is 75 to 95% and the pressure loss of air is 0.1 to 40 mm when passing through a thickness of 1 cm at a wind speed of 1 m/s, but the purpose is to reduce pressure loss. It is particularly preferable to use one in which the average diameter of the internal communication space is 1 to 10 mm.

Furthermore, the second ceramic porous body 6 having a network structure is a ceramic noodle obtained by extruding ceramic slurry into noodle shapes, stacking them so that they have porosity so that light does not pass straight through, and firing them. In the present invention, a second ceramic porous body 6 is disposed in the downstream layer, which has a non-linear internal communication space such as the ceramic foam or ceramic noodle, and through which light does not travel straight. By doing so, it is possible to obtain a breathable heat insulating material having a good radiation cooling blocking effect. It is preferable to use a ceramic noodle having a bulk specific gravity, an average diameter of an internal communication space, a porosity, and an air pressure loss similar to the above-mentioned ceramic foam.

The thickness of the second ceramic porous body 6 having a network structure is preferably 1/3 to 3 times the thickness of the first ceramic porous body 3 having a wall structure.

Furthermore, the heat insulating material of the present invention, which is formed by laminating a second ceramic porous body on a first ceramic porous body, has a pressure loss of 0.05 to 10 mm, particularly 0.1 to 1 mm, in the water column when air passes through a thickness of 1 cm at a wind speed of 1 m per second. It is preferable that

The breathable heat insulating material of the present invention is a honeycomb body formed of paper or plastic film and having the shape shown in FIG. 1A, or a plate on the other axial end surface of a roll core body having the shape shown in FIG. A core material is made by laminating and integrating soft polyurethane foam without a cell membrane formed into a shape, and ceramic is attached to this and dried, or a honeycomb body or a roll core body and a soft polyurethane foam without a cell membrane are each laminated. Ceramic is used as a core material, and after the ceramics are attached to each of these core materials, the ceramics are laminated and integrated when the ceramics are not dried, and after drying, the ceramic slurry attached to one axial end surface of the honeycomb body or roll core body is used as a core material. It can be produced by removing until the material is exposed and then sintering it. In this case, the core material is carbonized and removed, thereby forming a hollow portion.

Additionally, a method of attaching ceramic slurry to the core material, drying and sintering it, carbonizing the core material, and then removing the ceramic from one end surface in the axial direction of the honeycomb body or roll core body until a hollow portion appears is also adopted. However, this method is not recommended because it tends to cause damage to the porous ceramic body.

Here, the first ceramic porous body shown in FIG. 2A is made by bending a long strip of paper or plastic film to form a substantially diagonal 8 character, and the 8 character is continuous. paper or plastic film roll cores formed by bending them so that they are arranged in a large number of strips,
Or, by arranging a plurality of these roll cores in the vertical direction,
It is easily manufactured by attaching ceramic slurry to mutually bonded objects having the shape shown in FIG. 2A, removing the ceramic slurry as described above, and then drying and firing them. can do.

Furthermore, as described above, by constructing the second ceramic porous body with a ceramic foam formed from a soft polyurethane foam without a cell membrane, a cage-shaped ceramic foam consisting only of the edge portion of a regular dodecahedron can be formed. This is because the porosity is large, so the fluid passes through with little pressure loss, and the internal communication space is intricate, so when the fluid to be treated passes through this internal communication space, it makes sure to contact the grid. Make effective use of its effects. An example of this ceramic foam is shown in Fig. 3.
is the skeletal lattice of this ceramic foam, which has a three-dimensional network structure and has the same shape as the flexible polyurethane foam without cell membrane used to manufacture this ceramic foam. Reference numeral 9 denotes a three-dimensional network-like intricate non-linear internal communication space defined by this lattice 8, which constitutes a fluid flow path, and as described above, high-temperature fluid flows through this internal communication space (flow When passing through the grid 8, the high-temperature fluid collides with the grid 8, contacts it, and conducts heat to the grid 8.

There are no particular restrictions on the type of ceramic, but
From the viewpoint of thermal shock resistance, cordierite, mullite, alumina, silicon carbide, etc. are used.

The breathable heat insulating material of the present invention can be used by being attached to the exhaust port, exhaust passage, etc. of a heating furnace that heats by burning fuel such as gas or oil. side), the second porous ceramic body is on the downstream side, and the surface of the first ceramic porous body on the open side of the hollow part is the exhaust gas inlet surface, covering the exhaust port, the exhaust passage, or covering the object to be heated. and place it. Figure 5 shows one mode of use of the breathable heat insulating material of the present invention.
is a cylindrical heating furnace that is closed at one end (lower end) and connected to an exhaust pipe 11 at the other end (upper end), and a material to be heated such as oil flows inside this heating furnace 10. A reboiler tube 12 is provided, and a gas burner 14 is provided on one end wall 13 of the heating furnace 10.
is attached to the other end of the heating furnace 10, and the other opening 15 is closed, and the breathable heat insulating material 1 of the present invention is installed so that the first ceramic porous body 3 is placed on the upstream side (one end side), It is arranged with the second ceramic porous body 6 on the downstream side (the other end side). In this heating furnace 10, a substance to be heated such as oil flows in a reboiler tube 12 from an inlet end 12a to an outlet end 12b, and at this time, it is heated by the combustion heat of gas combusted by a gas burner 14. However, this combustion exhaust gas flows inside the heating furnace 10 toward the other end opening 15. In this case, since the breathable heat insulating material 1 is disposed in the vicinity of the other end opening 15 to close the opening 15, the combustion exhaust gas first passes through the first ceramic porous body 3 of the breathable heat insulating material 1. The exhaust gas flows through the cylindrical cells 2 and 2' constituting the second ceramic porous body 3, and then flows into the non-linear internal communication space 9 of the second ceramic porous body 3.
It passes through the internal communication space 9 while repeatedly coming into contact with and colliding with the grid 8 , and is further discharged through the exhaust pipe 11 through the opening 15 at the other end.

Therefore, the combustion exhaust gas simply flows through the other end opening 1.
Breathable insulation material 1, not those discharged from 5.
After passing through and exchanging heat with this, it is discharged.

Therefore, the object to be heated is heated by the radiant heat from the heating side, and also by the reflected heat of the radiant heat from the heating side by the air-permeable insulation material and the high-temperature exhaust gas passing through the air-permeable insulation material. It is also heated by radiant heat from the breathable insulation material based on the heat exchange that occurs, and therefore waste heat that conventionally was dissipated and was not used to heat the object to be heated can be used to heat the object to be heated. Therefore, the heating efficiency is extremely high. Moreover, as described above, the width and height of the cylindrical cells constituting the first ceramic porous body having a wall-like structure, the bulk specific gravity of the second ceramic porous body having a net-like structure, the average diameter of the internal communication space, When the porosity and air pressure loss are set to a specific range,
It has a high effect of dispersing thermal stress, has good thermal shock resistance, and has little dust accumulation in the exhaust gas and is less likely to become clogged, so it is less likely to inhibit combustion in a heating furnace or the like.

The arrangement of the breathable heat insulating material of the present invention is arbitrary, but as described above, the open side of the hollow part of the first ceramic porous body having a wall-like structure is the upstream side where the fluid flows, that is, the high temperature side. It is preferable to arrange the first porous ceramic body in this manner, and by setting the open side of the hollow part where deformation of the first ceramic porous body is particularly likely to occur due to heat as the high temperature side, the connection between the upstream side and the downstream side in the first porous ceramic body is Thermal stress caused by temperature differences between By disposing the second ceramic porous body having a network structure that prevents radiation cooling, excellent heat insulation properties can be obtained.

Furthermore, the breathable heat insulating material of the present invention can be added with a catalytic action to remove NOx generated in a heavy oil burner heating furnace, if necessary, and other configurations may also be made within the scope of the gist of the present invention. You can make various changes.

Effects of the invention As explained above, the breathable heat insulating material according to the present invention has excellent body heat stress resistance, is difficult to break even when used as a breathable heat insulating material in applications where large thermal stress is generated, and is resistant to heat insulation. It is highly effective.

[Brief explanation of the drawing]

Fig. 1 shows a breathable heat insulating material according to an embodiment of the present invention, A is a perspective view, B is a partially enlarged cross-sectional view, and Fig. 2 shows a breathable heat insulating material according to an embodiment of the present invention. 3 is a sectional view along the line of FIG. 1, FIG. 4 is a partially omitted enlarged perspective view showing an example of ceramic foam, and FIG. FIG. 5 is a schematic cross-sectional view showing one mode of use of the breathable heat insulating material of the present invention. 1... Breathable heat insulating material, 2, 2'... Cylindrical cell,
3...First ceramic porous body, 4...Wall body, 5...
...Hollow part, 6...Second ceramic porous body, 7...
Cavity part, 8... Skeleton lattice, 9... Non-linear internal communication space.

Claims (1)

[Claims for Utility Model Registration] 1. A hollow portion whose one axial end side is open to the outside in a wall constituting the cylindrical cells of a ceramic porous body having a wall-like structure formed by connecting a large number of cylindrical cells. and a ceramic porous body having a three-dimensional network structure having a non-linear internal communication space is laminated on the other axial end face of the ceramic porous body having a wall-like structure with the hollow portion closed. A breathable insulation material featuring: 2. The breathable heat insulating material according to claim 1, wherein the ceramic porous body having a wall-like structure is a honeycomb structure formed by connecting a large number of polygonal cylindrical cells. 3. Utility model registration claim 1, which is a roll core structure in which a porous ceramic body with a wall-like structure is formed by connecting a large number of a pair of cylindrical or elliptical cylindrical cells connected in a substantially diagonal figure 8 shape. Breathable insulation material as described in Section. 4 The width of the cylindrical cells constituting the wall-like porous ceramic body is 5 to 30 mm, and the height is 10 to 100 mm.
The breathable heat insulating material according to claim 2 or 3 of the utility model registration claim, which is mm. 5 Claims for registration of a utility model in which the ceramic porous body with a three-dimensional network structure is a ceramic foam having the same shape as a polyurethane foam obtained by sintering a soft polyurethane foam without a cell membrane and a ceramic slurry attached thereto. The breathable heat insulating material according to any one of items 1 to 4. 6. The breathable heat insulating material according to any one of claims 1 to 4, wherein the ceramic porous body having a three-dimensional network structure is a ceramic noodle formed by overlapping noodle-shaped ceramics. 7. As a ceramic foam or ceramic noodle, the bulk specific gravity is 0.25 to 0.7, the average diameter of the internal communication space is 0.2 to 10 mm, and the porosity is
75 to 95%, and the pressure loss of air is 0.1 to 0.1 in water column when passing through a thickness of 1 cm at a wind speed of 1 m/s.
The breathable heat insulating material according to claim 5 or 6 of the utility model registration claim using a material having a diameter of 40 mm.