JPH0337503B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a laminated insulation material for cryogenic temperatures, and is particularly suitable for wrapping inside vacuum insulated piping to prevent heat from penetrating into cryogenic parts. This invention relates to laminated insulation materials for extremely low temperatures.

[Background of the invention]

Conventional laminated insulation materials are reflective plastic films made by embossing a plastic film such as polyester with a thickness of about 10 to 30 μm, and depositing a metal such as aluminum on one or both sides of the film for the purpose of lowering the radiation rate. ,thickness
It is made by alternately laminating spacers of about 20 meshes woven from fibers such as polyester with a diameter of about 200 μm. Conventional laminated insulation materials have a decrease in insulation performance and an increase in manufacturing cost regarding insulation performance and cost. First, in terms of heat insulation performance, reflective plastic film is embossed and has an uneven surface. In comparison, the real area per unit projected area increases. Furthermore, since the vapor deposition is performed on a plastic film having an uneven surface, the thickness of the vapor deposited film becomes non-uniform, and the radiation rate becomes higher than that of the bright surface plastic film. On the other hand, when embossing is performed after vapor deposition, the vapor deposited film does not follow the elongation of the plastic film during processing, and the plastic surface of the base where the vapor deposited film breaks is exposed, further increasing the radiation rate. As described above, in conventional laminated heat insulating materials, the effective area of the reflective plastic film increases and the radiation rate is high, so that the heat insulating performance is greatly reduced.

Next, in terms of cost, when depositing metals such as aluminum onto embossed plastic films, it is difficult to uniformly deposit metals on uneven surfaces, so the deposition speed per unit area of the film is slow, and the process of depositing metals such as aluminum onto embossed plastic films is slow. The cost per area increases.

[Purpose of the invention]

An object of the present invention is to provide a laminated heat insulating material for cryogenic temperatures that has excellent heat insulation performance in a vacuum space and can be manufactured at low cost.

[Summary of the invention]

According to the present invention, a laminated heat insulating material is constructed by using uneven plastic films as spacers inserted between reflective plastic films without increasing the substantial area of the projection surface of the reflective plastic films or the radiation rate. In other words, the insulation performance of laminated insulation materials is influenced by radiation heat transfer and conductive heat transfer, but due to the decrease in radiation heat transfer, as a reflective plastic film with a small effective area of the projected surface and small radiation rate, uneven A bright plastic film with aluminum vapor-deposited on one or both sides of the plastic film without protrusions is used, and in order to reduce conductive heat transfer, a spacer with low contact thermal resistance with the bright plastic film is used on one or both sides. A non-deposited plastic film with a plurality of uneven protrusions formed on both sides and open spaces within the protrusions is used, and the two are alternately laminated to form a laminated heat insulating material.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the laminated heat insulating material for cryogenic use according to the present invention. The bright plastic film 1 is made of a flat polyester film with a thickness of 3 to 10 μm, with aluminum coated on one or both sides. It was deposited to a thickness of about 800 Å. Spacer 2 is
A non-evaporated plastic film with a plurality of uneven protrusions formed on one or both sides and an open space within the protrusions, in which case the film has a thickness of 10~
Embossed 30μm non-deposited polyester,
A large number of uneven projections 3 are formed on its surface. FIG. 2 shows a cross section when the bright plastic film 1 shown in FIG. 1 and the spacer 2 are laminated. Both contact at the top and bottom of the protrusion 3. According to this embodiment, since the bright plastic film 1 is flat, the substantial areas of the heat receiving and heat dissipating surfaces are the smallest in radiation heat transfer. Furthermore, in conduction heat transfer within the heat insulating material, the area of contact between the spacer 2 and the bright plastic film 1 is small. Furthermore, since the spacer 2 is not vapor-deposited with a metal such as aluminum, which has a high thermal conductivity, the thermal conductivity of the spacer 2 itself is low, and the thermal conductivity of the spacer 2 itself is low, and the amount of heat flowing between the spacer 2 and the bright plastic film 1 is small. The heat transfer distance is long because the spacer 2 is embossed, and the heat resistance is large. That is, for the above reasons, the cryogenic laminated heat insulating material according to the present invention has a very small amount of radiant heat transfer and a very small amount of conductive heat transfer, and has excellent heat insulating performance.

In addition, in terms of the cost of manufacturing the heat insulating material, the metal vapor deposition operation, which has a high cost ratio, is vapor deposition on a flat plastic film in the case of the present invention, and the high vapor deposition speed clearly results in low cost.

3 to 5 each show other embodiments of the present invention, and the difference between FIG. 3 and FIG. The point is that a large number of protrusions are provided that integrate the shell 5. In this example, when the laminated insulation material is subjected to vacuum baking treatment, the deformation of the projections of the spacer due to the heat is small, and the distance between the two bright plastic films can be kept constant, and the insulation performance is maintained even after baking treatment. This has the effect that it does not decrease. Here, the same effect can be obtained by using plastic fibers, plastic balls, etc. in place of the protrusions of the plastic shell.

4 differs from FIG. 1 in that a plurality of holes 7 are provided in the spacer of the embossed undeposited plastic film 4. In this embodiment, the bending rigidity of the spacer is reduced to make it easier to wrap the heat insulating material around a small diameter pipe or the like. In this embodiment, when a small-diameter pipe or the like is insulated, the winding is uniform. That is, a large surface pressure is not applied to the contact portion between the spacer and the bright plastic film, and the contact thermal resistance can be kept low, so that there is an effect that the heat insulation performance does not deteriorate.

Furthermore, the difference between FIG. 5 and FIG. 1 is that the embossed non-evaporated plastic film 4 and
The point is that the plurality of contact areas A of the bright plastic film 1 are integrated. According to this embodiment, when laminating a plurality of pairs of the non-deposited plastic film 4 and the bright plastic film 1, the bright plastic film 1 bites into the uneven portions of the non-deposited plastic film 4, increasing the area of the contact portion. This has the effect of preventing a decrease in thermal insulation performance due to a decrease in contact thermal resistance.

〔Effect of the invention〕

As described above, the present invention uses a bright plastic film with a flat surface and a non-evaporated plastic film which is formed by forming a plurality of uneven projections on one or both surfaces and opening the spaces within the projections. Since the laminated heat insulating material is constructed by laminating alternately, the radiant heat receiving and heat dissipating area of the bright surface plastic film can be minimized, and the contact area and thermal conductivity of the non-evaporated plastic film can be reduced. Moreover, because the heat transfer distance within the film is long, the insulation performance can be improved by about 50% compared to conventional laminated insulation materials. In addition, in terms of manufacturing costs, since metal can be deposited on a flat plastic film, the deposition process can be completed in a short time, and compared to conventional laminated insulation materials, the metal can be deposited on a flat surface.
Can be reduced by 40%.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the cryogenic laminated insulation material according to the present invention, FIG. 2 is a sectional view of FIG. 1, and FIGS. This is a third example showing another example.
FIG. 4 is a perspective view of the spacer, and FIG. 5 is a perspective view of the laminated heat insulating material. DESCRIPTION OF SYMBOLS 1...Bright surface plastic film, 2...Spacer, 3...Protrusion, 4...Non-deposited plastic film, 5...Plastic shell, 6...Vent hole,
7...hole.

Claims (1)

[Claims] 1. A flat bright plastic film with a metal such as aluminum vapor-deposited on one or both sides;
A laminated heat insulating material for extremely low temperatures, characterized in that non-evaporated plastic films having a plurality of protrusions formed on one or both sides and a non-evaporated plastic film with open spaces in the protrusions are laminated alternately. 2. Claim 1, wherein the protrusion is formed by embossing a non-evaporated plastic film.
Laminated insulation material for cryogenic temperatures as described in . 3. The laminated heat insulating material for cryogenic temperatures according to claim 1, wherein the protrusion is made of a plastic shell and is integrally formed with the non-evaporated plastic film.