JP2000249290A - Vacuum heat insulating body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily deform a vacuum heat insulating body into a form along a volume body to be insulated by providing grooves penetrating the end parts of one face or two faces of a core material, in the vacuum heat insulating body constituted of a core material made of powder material solidified into a flat plate, and an outer covering material made of plastic laminate having aluminum. SOLUTION: In a core material 1, for example, condesed silica powder and calcium silicate powder are mixed together, to form a powder compact compressively molded into a rectangular powder molding body. A plurality of grooves 2 are provided so as to penetrate the end parts of the one face of the core material 1 in parallel. Meanwhile, this vacuum heat insulating body 3 is formed so that the core material 1 is dried in a hot air drying furnace, and after inserting it into an outer covering material 4 made of an aluminum deposited laminate film of which the three sides are heat-fused, remaining one side is heat-fused and simultaneously released in the atmosphere. Stress due to atmospheric compression is concentrated to the grooves 2 of the core material 1, and the vacuum heat insulating body 3 is easily deformed in the direction of burying the spaces formed by the grooves 2. Hereby the cylindrical vacuum heat insulating body 3 can be formed simply and quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum insulator which can be used in a medium temperature range such as an electric water heater.

[0002]

2. Description of the Related Art In recent years, demands for higher performance of heat insulating materials in home electric appliances have been increasing in order to save energy.

[0003] A high-performance rigid urethane foam or a vacuum heat-insulating material using urethane as a core material is used as a heat insulating material for refrigerators and other cooling devices.

[0004] However, it has been difficult to apply heat insulating devices such as electric water heaters to a high operating temperature range.

Glass wool has generally been used as a heat insulating material that can be used in such a medium temperature range. However, in order to further save energy, it is necessary to increase the thickness of a heat insulating layer, and the size of equipment is increased. And other problems.

As one means for solving this problem, there is a vacuum insulator made of inorganic powder. The vacuum insulator disclosed in Japanese Patent Application Laid-Open No. 57-173689 is obtained by filling a film-shaped plastic container with powder having a single particle diameter of 1 μm or less and sealing the inside under reduced pressure. The effect is that since it is a fine powder, excellent heat insulating performance can be obtained at a degree of vacuum of 0.1 to 1 mmHg, which is easily industrialized.

[0007] Furthermore, Japanese Patent Application Laid-Open No. 60-0892 discloses a device for improving the problem of dust scattering and difficulty in handling the powder.
53 are disclosed. The content is a vacuum heat insulator using, as a core, an inorganic powder molded with fibers, an emulsifier, or the like.

[0008]

However, in the conventional configuration, in order to cover the entire circumference of the container to be thermally insulated of the heat insulation device or the electric cooling device, a plurality of vacuum heat insulators using a deformed core material are required. Must be used. Therefore, there is a problem that the molding process is complicated and the number of man-hours is increased, thereby reducing productivity.

[0009]

In order to solve the above-mentioned problems, a vacuum heat insulator according to the present invention comprises a core material made of a powdered material solidified into a flat plate and a jacket material made of a plastic laminate film having aluminum. Since the core material has a groove penetrating one or both ends, the core material can be easily deformed into a shape along the container to be thermally insulated.

In addition, since the thickness after deformation into the shape along the container can be predicted from the depth of the groove, variation in the thickness can be reduced, and there is no need for a press or the like in post-processing. Therefore, variation in the density of the vacuum heat insulator is suppressed, and there is no partial deterioration in heat insulation performance.

Further, since the core material is a rectangular parallelepiped and has at least four chamfers parallel to the direction in which the core material is inserted, when the core material is inserted into the jacket material, the powder at the end portion is Is less likely to collapse, and the degree of vacuum is less likely to deteriorate due to the deterioration of the sealing property.

Further, since the core material is a rectangular parallelepiped and has tapered at least two opposing sides, there is no gap at the seam when mounted on the outer periphery of the cylindrical container, so that the heat insulating performance is not deteriorated.

Further, since the core material has a groove penetrating one or both ends, and the flexible foam is formed on the surface having the groove, the aluminum of the jacket material is formed along the groove in the thickness direction of the core material. And the heat insulation performance is prevented from deteriorating due to heat leak.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention described in claim 1 of the present invention is a vacuum heat insulating material constituted by a core material made of a powder material solidified into a flat plate and a jacket material made of a plastic laminate film having aluminum. In the body, the core has a groove penetrating one or both ends.

The above-described vacuum heat insulator can be easily deformed into a shape along the container to be insulated.

Further, since the thickness after the deformation to the shape conforming to the container can be predicted from the depth of the groove, the variation in the thickness can be reduced, and there is no need for a press or the like in post-processing. Therefore, variation in the density of the vacuum heat insulator is suppressed, and there is no partial deterioration in heat insulation performance.

In the invention according to claim 2 of the present invention, since the core material is a rectangular parallelepiped and has tapered at least two opposing sides, the core material is mounted on the outer periphery of a cylindrical container.
There is no gap at the seam and the heat insulation performance does not deteriorate.

In the invention according to claim 3 of the present invention, the core material is a rectangular parallelepiped, and at least four sides parallel to the direction of insertion into the jacket material are chamfered. When inserted into the material, the powder at the end is less likely to collapse, and the degree of vacuum due to the deterioration of the sealability is less likely to occur.

In the invention according to claim 4 of the present invention, the core material has a groove penetrating one or both ends and has a flexible foam on the surface having the groove. Does not penetrate deeply in the thickness direction of the core material along the groove, and deterioration of heat insulation performance due to heat leak is suppressed.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

(Example 1) FIG. 1 is an external view of a core material according to an embodiment of the present invention. 1 is a core material made of an inorganic powder, and 2 is a groove formed on the surface of the core material.

The core material 1 is a powder compact obtained by mixing an agglomerated silica powder and a calcium silicate powder and compression-molding into a rectangular parallelepiped having a width of 230 mm, a length of 640 mm and a thickness of 7 mm.

A plurality of grooves 2 are provided in parallel so as to penetrate an end of one side of the core material 1. The shape of the groove 2 is a V-shape in which the width decreases as the depth increases. The depth of the groove 2 is 2 mm, and the width on the surface of the core material is 2 mm. Thirteen grooves were formed in parallel with the short direction of the rectangular parallelepiped so as to have a uniform pitch of 48 mm. The groove 2 was cut using a cutting tool.

FIG. 2 is an external view of a vacuum heat insulator according to one embodiment of the present invention, 3 is a vacuum heat insulator, and 4 is a jacket material. The structure of the jacket material 4 is a laminated film composed of a polyethylene terephthalate film (12 μm), an aluminum-deposited ethylene / vinyl alcohol copolymer film (15 μm), and a crystalline polypropylene film (50 μm).

The vacuum heat insulator 3 is formed by drying a molded and grooved flat core material 1 in a hot air drying oven at 120 ° C. for about 1 hour, and then forming an aluminum vapor-deposited laminated film heat-sealed on three sides. It was inserted into the workpiece 4. As it was, it was inserted into a vacuum chamber and maintained at 0.1 torr or less for 2 minutes, and the remaining one side was heat-sealed and simultaneously released to the atmosphere.

In the obtained vacuum heat insulator, stress due to atmospheric compression was concentrated on the groove 2 of the core material 1 and was deformed in a direction to fill the space formed by the groove. As a result, a cylindrical vacuum heat insulator 3 shown in FIG. 2 was obtained.

The thermal conductivity and the internal pressure of the vacuum insulator were measured. Thermal conductivity was measured at an average temperature of 24 at four random locations.
It measured with the thermal conductivity measuring device set to ° C. The internal pressure was determined by reading the point at which swelling started due to the differential pressure in the vacuum chamber. As a comparative example, a core material without a groove was prepared in the same manner, a flat vacuum heat insulator was obtained, and then physical properties in a case of being rolled into a cylindrical shape in a subsequent process were measured. The results are shown in (Table 1).

[0028]

[Table 1]

The thermal conductivities at four points measured at random are:
In the examples of the present invention, the values were almost constant, but in the comparative examples, the values varied in the range of 0.0012 kcal / mh ° C.

This is because, due to the variation in the hardness of the core portion, the collapsed thick portion of the core material caused by the difference between the inner diameter and the outer diameter is partially compressed by the cylindrical roll processing, and the variation in the density occurs. It is because.

Regarding the processing of the groove 2, the same effect was obtained when the fin was previously provided in the compression molding jig of the core material and the groove was provided.

As described above, since the core material has the groove penetrating the end, the shape of the vacuum heat insulator can be deformed into a shape along the container to be insulated only by the stress due to the atmospheric compression.

In addition, since the thickness after the deformation into the shape along the container can be predicted from the depth of the groove, the variation in the thickness can be reduced, and there is no need for a press or the like in post-processing. Therefore, variation in the density of the vacuum heat insulator is suppressed, and there is no partial deterioration in heat insulation performance.

Example 2 FIG. 3 is a sectional view of an embodiment of the present vacuum heat insulator. The core material 1 was tapered at the joint 5 of the cylindrical vacuum heat insulator 3. The taper was applied in parallel with the short end of the core material so that the cross-sectional size of the tapered portion was 230 mm * 16 mm, and a similar taper was provided on the opposite side of the core material.

As described above, when the vacuum heat insulator 3 is formed in a cylindrical shape, a state where the tapered surfaces overlap each other can be produced.

Table 2 shows that the outer shape is 190 mm and the height is 2
9 Hot water of 100 ° C in a 50 mm stainless steel cylindrical container
It is the result of measuring the temperature after 2 hours on the outer peripheral surface of the seam 5 when the cylindrical vacuum heat insulator 3 was wound around the container and fixed until the second minute. For comparison, the temperature on the outer peripheral surface of the joint 5 when no taper was provided was measured. The outside air temperature at the time of measurement was 30 ° C.

[0037]

[Table 2]

As compared with the comparative example, a temperature drop of 6 ° C. was observed in the example. Since the temperature of the hot water was almost the same as 85 ° C. and the surface temperature was different, it can be said that there was a difference in the heat insulation performance at the joint. Further, since the temperature at a location 100 mm away from the seam was 43 ° C., there was almost no decrease in the heat insulation performance of the seam in the example.

(Embodiment 3) The core material is a rectangular parallelepiped,
The four sides shown in the chamfered portion 6 in FIG. 1 are chamfered. The chamfered portion is 1 mm from the end, and when the core material is inserted into the jacket material, the powder at the end hardly collapses,
The deterioration of the degree of vacuum caused by the deterioration of the sealing property did not occur.

[0040]

As described above, the vacuum insulator of the present invention is
In a vacuum heat insulator composed of a core material made of a powder material solidified into a flat plate and a jacket material made of a plastic laminated film containing aluminum, the core material has a groove penetrating one or both ends.

Therefore, it can be easily deformed into a shape along the container to be insulated.

Further, since the thickness after the deformation to the shape conforming to the container can be predicted from the depth of the groove, the variation in the thickness can be reduced, and there is no need for a press or the like in post-processing. Therefore, variation in the density of the vacuum heat insulator is suppressed, and there is no partial deterioration in heat insulation performance.

In the vacuum heat insulator of the present invention, since the core material is a rectangular parallelepiped and has tapered at least two opposing sides, there is no gap at the seam when installed on the outer periphery of the cylindrical container. Does not worsen.

In the vacuum heat insulator of the present invention, the core material is a rectangular parallelepiped, and at least the core material is parallel to the direction of insertion into the jacket material.
Since the sides are chamfered, the powder at the ends is less likely to collapse when the core material is inserted into the outer cover material, and the degree of vacuum due to the deterioration of the sealing property is less likely to occur.

[Brief description of the drawings]

FIG. 1 is an external view of a core material according to an embodiment of the present invention.

FIG. 2 is an external view of a vacuum insulator according to an embodiment of the present invention.

FIG. 3 is a sectional view of a vacuum insulator according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core material 2 Groove 3 Vacuum heat insulator 4 Jacket material 5 Chamfer part 6 Joint

Claims (3)

[Claims] 1. A vacuum heat insulator composed of a core material made of a powdered material solidified into a flat plate and a jacket material made of a plastic laminate film having aluminum, wherein the core material has one or both ends. A vacuum insulator having a penetrating groove. 2. A vacuum heat insulator comprising a core material made of a powdered material solidified into a flat plate and a jacket material made of a plastic laminate film having aluminum, wherein said core material is a rectangular parallelepiped and at least faces each other. The vacuum heat insulator according to claim 1, wherein the vacuum heat insulator has a taper on two sides. 3. A vacuum heat insulator comprising a core material made of a powdered material solidified into a flat plate and a jacket material made of a plastic laminated film having aluminum, wherein said core material is a rectangular parallelepiped, and at least 3. The vacuum heat insulator according to claim 1, wherein chamfering is performed on four sides parallel to a direction of insertion into the material.