JPH05106783A - Filter for vacuum heat insulating wall - Google Patents

Abstract

PURPOSE:To provide a filler for a vacuum heat insulating wall which has excellent pressure resistant strength and by which conditions of fiber contact points exerting influence upon a degree of inside vacuum and heat conductivity can be maintained moderately. CONSTITUTION:A filler for a vacuum heat insulating wall is constituted in such a way that inorganic fibrous parts whose orientation directions are in the thickness (z) direction are arranged partially and uniformly dispersedly in an inorganic fibrous mat shape body 1 molded by orienting fiber in the plane (x, y) directions, and pressure resistant strength is improved by means of the thickness (z) directionally oriented fiber, and an area ratio of these parts is also diminished, so that deterioration of a heat conductivity rate can be restrained to the minimum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filler for a vacuum heat insulating wall, and more particularly, it is used for a vacuum heat insulating wall formed by filling a double wall with a filler made of an inorganic fiber having an excellent heat insulating effect and sealing it in a vacuum. The present invention relates to a filler for a vacuum insulation wall.

[0002]

2. Description of the Related Art Conventionally, as a structure of a heat insulating container that needs to perform high-order heat insulation in a large heat insulating container or the like, the container has a double wall and the inside of the double wall is filled with inorganic particles or fibers excellent in heat insulating effect. It is known that it is vacuum sealed. It is known that this kind of heat insulating wall exerts an extremely excellent heat insulating property by eliminating the effects of gas convection and heat transfer at a certain vacuum level due to the synergistic effect of vacuum pressure level and powder or fiber filling. There is.

The reason for this is that in the correlation between the mean free path of the gas molecules inside determined by the vacuum pressure and the size of the voids such as powder having voids, the average free path of the gas molecules at a certain vacuum pressure is the void. Longer lengths are believed to be the result of limiting the free path of the gas, which affects thermal conductivity. The adiabatic performance at this time is determined by the amount of heat transferred through the inside of the powder or the like and their contact points.
When 0.1 to 1 Torr or less, the thermal conductivity at an average temperature of 20 ° C is 10 ^-2 to 10 ^-3 Wm / K, and in the case of fiber type, the fiber diameter is 1 to 10
The SiO ₂ component rich inorganic fiber is filled with μ and the vacuum degree is set to 0.1.
It is known that the thermal conductivity will be on the order of 10 ^-3 Wm / K when it is set to Torr or less.

[0004]

However, when the inside of the double wall of the heat insulating wall has a high degree of vacuum, they are deformed under the influence of a large atmospheric pressure. In the case of a rectangular heat-insulating container, the membrane that composes the double wall is deformed by the effect of atmospheric pressure, and this deforming pressure also compresses the filler inside, increasing the contact pressure of the powder and fiber inside, and Even if the conditions are improved, there is a problem that the thermal insulation property of the corner is considerably lowered due to the deformation due to the atmospheric pressure which occurs subsequently.

In order to solve such a problem, the applicant of the present application has used a matte made of an inorganic fiber rich in SiO ₂ component, which is excellent in heat insulating property, as a filler for filling the double wall, and the mat has a pressure equal to the atmospheric pressure. It was proposed that the fiber mat should be compressed in advance and filled in the double wall and then the inside should be evacuated so that the fiber mat contributes to heat insulation and at the same time it is used as a pressure resistant member in the double wall. When the mat is pre-compressed, the contact points between the fibers increase considerably, so even if the fibers that make up the mat are arranged in the plane direction, the improvement of the heat insulating effect cannot be expected so much, and the mat is compressed, so it is apparent. There were problems such as an increase in specific gravity and an increase in weight.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a filler for a vacuum heat insulating wall which is capable of maintaining appropriate conditions such as the internal vacuum degree and the contact point of fibers, and is excellent in pressure resistance. It was made for that purpose.

[0007]

That is, the filler of the vacuum heat insulating wall of the present invention has a portion in which the orientation direction of the inorganic fibers is the thickness direction in the inorganic fiber mat-like body formed by orienting the fibers in the plane direction. It is characterized in that it is provided partially and uniformly.

[0008]

In the present invention, a mat formed by orienting SiO ₂ component-rich inorganic fibers in the plane direction is assumed as the heat insulating material filled in the heat insulating wall. When the fibers are arranged in the planar direction, the mat has no fibers extending in the thickness direction, and therefore the heat transfer property in the thickness direction is considerably high in the unpressurized state. However, when the compressive strength in the plane coordinate x, y axis direction and the compressive strength in the z axis direction orthogonal to these in the fiber mat having such an orientation are compared, the mechanical properties of the latter are considerably higher than those of the former. Fall below.

Further, in order to increase the compressive strength of this mat, the orientation of the fibers in the z-axis direction may be enhanced, but naturally, the heat insulating property is remarkably lowered.
Considering the harmony point between the compressive strength against the external pressure applied to the fiber mat and the heat transfer property, even if the mat is molded in the state with the best heat insulation, this will be sacrificed by compression.
Better heat insulation results when the fiber orientation in the z-axis direction is increased and compression strength is added at the cost of less heat insulation.

In this case, as shown in FIG. 1, the fiber mat 1
The area in the xy axis direction (plane direction) of L₁, Z-axis direction (thickness
Area) of the fiber array₂, Thermal conductivity of each
Λ_xy, Λ_ZThe elastic modulus is E_xy, E_ZThen (subscript
xy and z indicate the respective directions) of the entire fiber mat
If the average thermal conductivity is λ and the elastic modulus is E, then λ = (λ_ZL₁+ Λ_xyL₂) / (L₁+ L₂) ... E = (E_ZL₁+ E_xyL₂) / (L₁+ L₂) ... In this case, L₁: L₂= 9: 1, λ_xy= 0.01 W / m
k, λ_Z= 0.004W / mk, E_xy= 200kgf / cm², E_Z= 17kgf
/cm² Substituting into the equation, λ = 0.0046W / mK E = 35.3 kgf / cm²  Becomes

That is, in the mat in which all the fibers are oriented in the xy plane, λ = 0.004 W / mK and E = 17 kgf / cm ² , whereas only the portion corresponding to 10% area is arranged in the thickness direction. The thermal conductivity is 0.0046 W / mK, which is slightly high, but the elastic modulus is 35.3 kgf / cm ^2, which is more than double the compressive strength.

[0012]

Embodiments of the present invention will be described below. 1 is a perspective view of an essential part of an embodiment of the present invention, and FIG. 2 is a perspective view of another embodiment.

[Example 1] SiO ₂ component 35 to 45% by weight, Al ₂ O
₃ components 10-20% by weight, CaO component 30-40% by weight, MgO component
A fiber mat 1 having a thickness of 2 cm and comprising 5 to 10% by weight and a mineral fiber having a fiber diameter of 5 to 8 μm, in which the fibers are oriented in the xy plane direction and the elastic modulus in the same plane direction is 200 kgf / cm ² ,
Same thermal conductivity of 0.01 W / mk, z-axis elastic modulus of 17 kgf / c
Prepare m ^{2 with} the same thermal conductivity of 0.004 W / mk, and make the area ratio 9: 1 on this mat 1 as shown in FIG. 1.
2. Square-shaped through-holes 2 ... 2 having a size of 2 cm are evenly distributed, and then the matte-piercing pieces 3 ... 3 are turned 90 degrees, and the fibers are inserted into the holes again along the z-axis direction. Filler A was used. When the elastic modulus in the thickness direction and the thermal conductivity of the entire mat were measured, the elastic modulus was 35.3 kgf / cm ² , and the thermal conductivity was 0.0046 W / mK.

[Example 2] The mineral fiber mat 1 used in Example 1 was used and bent in a corrugated shape so that the transverse component and the longitudinal component were exactly 9: 1 without providing a hole. Then, a filling material A having an envelope thickness of 4 cm was obtained. When the elastic modulus and the thermal conductivity of the entire mat 1 in the thickness direction were measured, both the elastic modulus and the thermal conductivity were substantially the same as those in Example 1.

[0015]

As described above, the filler A of the vacuum heat insulating wall according to the present invention has a fiber orientation based on the plane direction, but is partially oriented in the thickness direction. The overall elastic modulus in the thickness direction is significantly improved and the compressive strength is excellent. Moreover, since the fiber arrangement in the thickness direction is a very small area compared to the plane arrangement part, the heat insulation due to this is small and practical. It has very few problems and has a very good performance as a filler in a vacuum insulation wall.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a perspective view of another embodiment.

[Explanation of symbols]

A ... Filler, 1 ... Fiber mat, 2 ... Through hole, 3 ...
Mat perforated piece

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[Procedure amendment]

[Submission date] December 18, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

However, when the inside of the double wall of the heat insulating wall has a high degree of vacuum, they are deformed under the influence of a large atmospheric pressure. for insulated container forms a rectangular shape, Ri termination material which binds the double wall is deformed due to the influence of atmospheric pressure, there is a problem that double walls will close, charge
The pressure resistance of the filler is required.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction content]

In order to solve such a problem, the applicant of the present invention is composed of SiO ₂ component rich fiber having excellent heat insulating property.
An inorganic fiber mat in which the fibers are arranged in the plane direction is used as a filling material for the double wall, and this mat is pre-compressed at a pressure equal to the atmospheric pressure. We have proposed that the vacuum can make the fiber mat contribute to heat insulation and at the same time make it a pressure resistant member in the double wall, but even if the fiber mat is pre-compressed , the heat insulation effect of the mat is proposed.
As a result, the effect of improving the pressure resistance cannot be expected so much, and since the mat is compressed, the apparent specific gravity is increased and the weight is increased.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

In the present invention, a mat formed by orienting SiO ₂ component-rich inorganic fibers in the plane direction is assumed as the heat insulating material filled in the heat insulating wall. If an array of fibers in a planar direction, extremely fibers extending in the thickness direction in the mat
Heat transfer in the thickness direction since the small Te is very small,
The heat insulation is quite high. However, when the compressive strength in the plane coordinate x, y axis direction and the compressive strength in the z axis direction orthogonal to these in the fiber mat having such an orientation are compared, the mechanical properties of the latter are considerably higher than those of the former. Fall below.

Claims (1)

[Claims] 1. An inorganic fiber mat-like body formed by orienting fibers in a plane direction, wherein a portion in which the orientation direction of the inorganic fibers is the thickness direction is partially and uniformly dispersed. Vacuum insulation wall filler.