MOLDED HEAT INSULATION MEMBER COMPRISING CAPILLARY-ACTIVE ELEMENTS

Abstract

Thermal insulation body comprising a thermally insulating core having holes filled with a capillary-active material, wherein the thermally insulating core is capillary-inactive and the capillary-active material in the holes comprises capillary-active wicks.

Claims

1-14. (canceled)

15. A thermal insulation body, comprising: a thermally insulating core having holes filled with a capillary-active material, wherein the thermally insulating core is capillary-inactive and the capillary-active material in the holes comprises capillary-active wicks.

16. The thermal insulation body according to claim 15, wherein the holes have a diameter of 100 to 6000 μm.

17. The thermal insulation body according to claim 15, wherein the capillary-active wicks have a density per unit area of 10 to 10 000 wicks/m.sup.2.

18. The thermal insulation body according to claim 15, wherein the cross-sectional area of the capillary-active wicks is from 0.001 to 1 mm.sup.2.

19. The thermal insulation body according to claim 15, wherein the capillary-active wicks comprise a material selected from the group consisting of yarns, twines, threads, textured spun threads, filaments and cords.

20. The thermal insulation body according to claim 15, wherein the material of the capillary-active wicks is selected from the group consisting of basalt, silica, E glass, C glass and glass.

21. The thermal insulation body according to claim 15, wherein the capillary-active wicks project out of the thermal insulation body or end flush with the surface of the thermal insulation body.

22. The thermal insulation body according to claim 15, wherein the thermally insulating, capillary-inactive core is a thermal insulation sheet, a thermal insulation mat or a thermal insulation bed.

23. The thermal insulation body according to claim 15, wherein the thickness of the thermally insulating, capillary-inactive core is 3 to 150 mm.

24. The thermal insulation body according to claim 15, wherein the thermally insulating, capillary-inactive core has a thermal conductivity of less than 0.025 W/(mK).

25. The thermal insulation body according to claim 15, wherein the thermally insulating, capillary-inactive core contains hydrophobic fumed silica.

26. The thermal insulation body according to claim 15, which comprises at least one capillary-active outer layer on one or both sides of the thermally insulating, capillary-inactive core, with the capillary-active wicks ending within or protruding from the capillary-active outer layer.

27. The thermal insulation body according to claim 15, wherein the material of the capillary-active outer layer is selected from the group consisting of a capillary-active textile fabric, a capillary-active open-pore foam and/or a capillary-active porous layer.

28. The thermal insulation body according to claim 15, which has a layer that acts as a vapor barrier or vapor retarder between the thermally insulating, capillary-inactive core and the capillary-active outer layer, through which the capillary-active wicks are conducted.

Description

[0034] A further embodiment of the invention has a layer that acts as a vapour barrier or vapour retarder between the thermally insulating, capillary-inactive core and the capillary-active outer layer, through which the capillary-active wicks are conducted. Suitable materials for a vapour barrier or a vapour retarder are, for example, glass, polyethylene or metals such as aluminium.

[0035] FIG. 1 shows the regular penetration of capillary-active wicks into a thermal insulation board laminated all-round with a capillary-active material. The resultant inventive thermal insulation body has elevated tensile strength and low thermal conductivity. A=regular penetration of capillary-active wicks; B=all-round lamination with capillary-active material, for example fabric or combination with mortar.

[0036] FIG. 2 shows a thermal insulation body produced by tufting,

wherein the thermally insulating, capillary-inactive core is a thermal insulation board (1) containing hydrophobized silica and an IR opacifier,
wherein the capillary-active outer layer consists of mineral wool (2) and
wherein the capillary-active wicks comprise glass fibres (3).
The final mechanical strength can be increased by bonding to the wall, in that the lugs are joined flat to one another or are bonded at least locally.

[0037] FIG. 3 shows the effect of the capillary-active wicks. For this purpose, the thermal insulation body is introduced into a water-filled tank. The thermal insulation body floats with a small gap from the edge of the tank in order to minimize free convection/evaporation and to always assure good contact with the water. The arrangement is on a balance. Under defined flow conditions in a fume hood at 22° C., the decrease in mass with time is measured simultaneously. The thermal insulation body is

[0038] a) a hydrophobic board (200×200×35 mm) which is open to diffusion, the main constituent of which is a hydrophobized fumed silica (CALOSTAT®, Evonik Industries). The water vapour has to diffuse through the board before there is free convection above it. In FIG. 3, the values are marked with o.

[0039] b) a CALOSTAT® board with 3 capillary-active wicks and with a capillary-active topsheet (170×200 mm). Each wick consists of about 7000 individual glass fibres having a diameter of about 10 μm. In FIG. 3, the values are marked with x. Here, the water is conveyed into the outer layer through the wicks, where there is evaporation with free or forced convection because of the fume hood. The evaporation rate is about three times higher with wicks than without capillary-active wicks. The 3 capillary-active wicks are already completely sufficient to permanently wet the topsheet. In FIG. 3, the amount of water evaporated in grams is plotted against time in minutes.

[0040] FIG. 4 shows a calculated thermal conductivity and tensile strength of a stepped thermal insulation body comprising a capillary-inactive thermal insulation board open to diffusion, CALOSTAT®, and a capillary-active top layer and capillary-active wicks. For the tensile strength, the assumption is made that all capillary-active wicks hold up to the tear limit and there are no defects, the capillary-active wicks are made from glass fibres (tensile strength 3000 MPa) and the tensile strength of CALOSTAT® is 0 kPa. In addition, the capillary-active outer layers are assumed, in a simplification, to have the thickness d=0. In FIG. 4, the x axis represents the number of threads (diameter of the individual thread=10 μm) per wick, the left-hand y axis represents lambda in W/(mK) (marker in FIG. 4: rhombus), and the right-hand y axis represents the tensile strength in kPa (marker in FIG. 4: square).

[0041] Starting from 20 mW/(mK) for the capillary-inactive, thermally insulating core, the thermal conductivity increases with increasing number of capillary-active wicks. The capillary-active wicks are stepped here in a pattern of 4×5 cm.sup.2. The number of individual threads per wick is varied. Not until 10 000 threads per wick does the thermal conductivity rise by nearly 0.5 mW/(mK). This corresponds to an effective wick cross section of 0.8 mm. The pattern chosen results in 500 wicks per square metre. Thus, while thermal insulation decreases only slightly, tensile strength increases distinctly.

[0042] A real measurement for a stepped thermal insulation body made from a CALOSTAT® board having a thickness of 30 mm, capillary-active wicks as specified in the description for FIG. 3, and with 12 mm of mineral wool, Akustic EP3 ISOVER St. GOBAIN, as outer layer on both sides, gives an effective thermal conductivity of 0.024 W/(mK). The measurement was conducted with a board device at bulk temperature 10° C. with a contact pressure of 2000 Pa. The theoretical value is 0.025 W/(mK). This shows good agreement of theory and practice.