VACUUM THERMAL INSULATION SYSTEM LNCLUDLNG INORGANIC MATERIAL THEREIN AND MANUFACTURING METHOD THEREOF
Technical Field
The present invention relates to a vacuum insulation panel (VIP) including inorganic fiber as core material and a stainless steel sheet as an envelope, and more particularly, to a porous vacuum insulation panel including inorganic fiber, which reduces a weight of the core material by perforating the inorganic fiber and is easily manufactured by wrapping the perforated inorganic fiber with inorganic fiber texture, and its manufacturing method.
Background Art
In general, because a vacuum insulation panel (VIP) has a vacuum therein, it is important that core material must have a strength capable of enduring atmospheric pressure to maintain its shape. The core material used for the vacuum insulation panel is made of inorganic materials, such as silica powder, glass fiber, and calcium silicate- based molding material, and organic materials, such as polyurethane and polystyrene foam agent including a fine open cell structure.
A method for forming the core material of the vacuum insulation panel including silica powder, which is inorganic material, and polyurethane foam and polystyrene foam of the open cell structure, which are organic materials, has been well known. For example, the polyurethane foam used in a conventional refrigerator shows thermal conductivity of 0.015 ~ 0.02kcal/mh°C in insulation capability. A vacuum
insulation panel manufactured including silica powder, which has insulation capability better than that of the polyurethane foam, polyurethane foam and polystyrene foam of the open cell structure shows thermal conductivity of 0.004 ~ 0.007kcal/mh° in insulation capability. However, because a vacuum insulation panel including inorganic fiber as core material has thermal conductivity of 0.0020 ~ 0.0029kcal/mh°, it sufficiently satisfies requirements of the insulation panel.
However, the conventional vacuum insulation panel uses the core material, in which inorganic fibers are heated and pressurized to be closely contacted to each other, to endure atmospheric pressure. As the result, the conventional vacuum insulation panel has a disadvantage that the insulation capability is good but the insulation panel is too heavy.
Disclosure of Invention
Accordingly, it is an object of the present invention to provide a porous vacuum insulation panel and its manufacturing method in which light inorganic fiber material having insulation capability of inorganic fiber is used.
It is another object of the present invention to provide a porous vacuum insulation panel including light inorganic fiber and its manufacturing method, which has insulation capability more than 0.0020 ~ 0.0029kcal/mh°C by including inorganic fiber as core material.
To achieve the above objects, the porous vacuum insulation panel including inorganic fiber according to the present invention includes core material of inorganic fiber having a number of holes, and an envelope containing the core material therein
and maintaining a predetermined vacuum condition.
In another aspect of the present invention, the method for manufacturing a porous vacuum insulation panel including inorganic fiber includes the steps of: forming an inorganic fiber mold body by piling up glass fibers and compressing, heating and pressurizing the glass fibers; forming holes of a predetermined diameter in the inorganic fiber mold body; and putting the perforated inorganic fiber mold body in a predetermined space and vacuuming the inside of the space.
Brief Description of the Drawings
Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawing in which:
FIG. 1 is a cross-sectional view of a porous vacuum insulation panel including inorganic fiber according to the present invention;
FIG. 2A is a perspective view of an inorganic fiber mold body according to the present invention;
FIG. 2B is a plan view of the inorganic fiber mold body according to the present invention; FIG. 3 is a cross-sectional view showing a state that the inorganic fiber mold body is wrapped with inorganic fiber texture; and
FIG. 4 is a configuration view for explaining a method of manufacturing the vacuum insulation panel.
Best Mode for Carrying Out the Invention
FIG. 1 is a cross-sectional view of a porous vacuum insulation panel including inorganic fiber according to the present invention. The vacuum insulation panel includes an inorganic fiber mold body 10, which has holes of a predetermined size and serves as core material, inorganic fiber texture 20 wrapping the inorganic fiber mold body, and a stainless steel sheet 30 of a predetermined thickness, which contains the inorganic fiber texture 20 therein, forms a predetermined vacuum and serves as an envelope. FIG. 2A is a perspective view of an inorganic fiber mold body 10 according to the present invention, and FIG. 2B is a plan view of the inorganic fiber mold body 10 according to the present invention.
Here, the holes 11 formed in the inorganic fiber mold body 10 has a diameter within a range of 3 ~ 20mm, preferably, 5mm. Furthermore, the holes are in the form of a circle, but may be in the form of a triangle, a rectangle or a polygon. A thickness of the stainless steel sheet 30 is 0.005 ~ 0.15mm, and a degree of vacuum formed by the stainless steel sheet 30 is 10"6 ~ lO^Torr.
FIG. 3 is a cross-sectional view showing a state that the inorganic fiber mold body is wrapped with inorganic fiber texture, showing the inorganic fiber mold body 10 having the holes 11, and the inorganic fiber texture 20 wrapping the inorganic fiber mold body 10.
A method for manufacturing the porous vacuum insulation panel including inorganic fiber according to the present invention will be described as follows.
First, the inorganic fiber mold body 10 is formed by piling up inorganic fibers and compressing, heating and pressurizing them. The inorganic fiber mold body made
through the above steps has the holes 11 as shown in FIGS. 2 A and 2B.
The inorganic fiber mold body having the holes is wrapped with the inorganic fiber texture 20. The inorganic fiber texture prevents weld defect due to fiber chips when the stainless steel sheet is welded, by removing the fiber chips generated when the inorganic fiber mold body is perforated.
Therefore, as shown in FIG. 1, the inorganic fiber mold body having the holes is sealed in the inside of the stainless steel sheet 30 in a vacuum condition. It will be described in more detail as follows.
FIG. 4 is a configuration view for explaining the method of manufacturing a vacuum insulation panel. The inorganic fiber mold body 10 is sealed with the stainless steel sheet 30, and then, a pipe 40 for discharging air from the sealed space is mounted.
Therefore, when a predetermined degree of vacuum (for example, 10"6 ~ 10" ^orr) is formed after the inside air is discharged through the pipe, the inside of the space formed by the stainless steel sheet 30 maintains the vacuum condition by cutting the pipe.
The vacuum insulation panel according to the present invention can make products of the optimum insulation condition by measuring the insulation capability according to a perforated rate.
For example, referring to a Table 1, there will be explained an embodiment that a change of insulation capability of the inorganic body, which is 400g in weight, 250mm in width, 250mm in length, and 20mm in height, is measured according to the perforated rate.
Table 1. Change of weight and insulation capability according to perforated rate
Embodiment 1
In a first embodiment of the vacuum insulation panel according to the present, o the core material is formed by heating and pressurizing glass fiber at temperature less than 500°C. The core material as the envelope is sealed by the stainless steel sheet, and the inside of the core material maintains 10"5Torr. As shown in the Table 1, the insulation capability of the vacuum insulation panel manufactured as the above has thermal conductivity and weight determined by a Rapid-k value.
Embodiment 2
In a second embodiment of the vacuum insulation panel according to the present, the core material is formed by heating and pressurizing glass fiber at temperature less than 500°C. The core material has about 200 holes of 5mm in diameter. The core material as the envelope is sealed by the stainless steel sheet, and the inside of the core material maintains 10"5 Torr. As shown in the Table 1, the vacuum insulation panel manufactured as the above has weight reduced from 400g to 370g, but has the
same insulation capability as the first embodiment.
Embodiment 3
In a third embodiment of the vacuum insulation panel according to the present, the core material is formed by heating and pressurizing glass fiber at temperature less than 500°C. The core material has about 400 holes of 5mm in diameter. The core material as the envelope is sealed by the stainless steel sheet, and the inside of the core material maintains 10"5 Torr. As shown in the Table 1, the vacuum insulation panel manufactured above has weight reduced from 400g to 350g, but has the same insulation capability as the first and second embodiments.
Embodiment 4
In a fourth embodiment of the vacuum insulation panel according to the present, the core material is formed by heating and pressurizing glass fiber at temperature less than 500°C. The core material has about 600 holes of 5mm in diameter. The core material as the envelope is sealed by the stainless steel sheet, and the inside of the core material maintains 10"5Torr. As shown in the Table 1, the vacuum insulation panel manufactured above has weight reduced from 400g to 320g, but has the insulation capability (0.0021) slightly less than the insulation capability (0.0023) of the first to third embodiments.
In the above embodiments of the vacuum insulation panel according to the present invention, the core material has the perforated rate of 18%, but also a core material having the perforated rate of maximum 25% has the same effect.
Meanwhile, because the weight of the vacuum insulation panel is reduced as the perforated rate is increased, there is little difference in thermal conductivity in spite of the light core material.
Industrial Applicability
As described above, the porous vacuum insulation panel and its manufacturing method can reduce the weight of the insulation panel and increase the insulation effect by forming a number of holes of a predetermined diameter in inorganic fiber used as the core material. As the result, the present invention can reduce a manufacturing cost of products and waste of energy.