VACUUM INSULATING PANEL

Abstract

The present invention relates to a vacuum insulating panel (VIP). The VIP comprises an insulating core (2) having upper (3) and lower surfaces (4) and at least one substantially planar reinforcing member (5) arranged on the upper (3) or lower surface (4) of the core (2). The reinforcing member (5) is porous and substantially rigid. The VIP further comprises a barrier envelope, optionally in the form of a barrier film (6), arranged to envelop the insulating core (2) and the planar member (5). The present invention also relates to methods of manufacturing a vacuum insulating panel (VIP).

Claims

1-28. (canceled)

29. A vacuum insulating panel comprising: a porous insulating core having an upper surface and a lower surface and sides, the insulating core is constructed from a microporous insulating material formed from a powder material; at least one reinforcing member arranged on the upper or lower surface of the insulating core to reinforce the core, the reinforcing member is formed of a porous material, and is substantially rigid; the at least one reinforcing member and the insulating core form a hybrid core and the at least one reinforcing member does not form a thermal bridge across the insulating core; an envelope, arranged to envelop the hybrid core, the envelope maintains an applied vacuum within the envelope; density of the insulating core within the vacuum insulating panel is from 100 kg/m.sup.3 to 160 kg/m.sup.3; and thermal conductivity of the vacuum insulating panel is in the range of from 3.0 mW/m.Math.K to 4.0 mW/m.Math.K.

30. The vacuum insulating panel according to claim 29, having an upper reinforcing member arranged on the upper surface of the insulating core and a lower reinforcing member arranged on the lower surface of the insulating core.

31. The vacuum insulating panel according to claim 29, wherein the at least one reinforcing member has a compressive strength of between 95 kPa and 150 kPa.

32. The vacuum insulating panel according to claim 29, wherein the hybrid core has a compressive strength of between 95 kPa and 150 kPa.

33. The vacuum insulating panel according to claim 29, wherein the density of the at least one reinforcing member is lower than that of the insulating core.

34. The vacuum insulating panel according to claim 30, wherein the upper reinforcing member and the lower reinforcing member each have a density that is lower than that of the insulating core.

35. The vacuum insulating panel according to claim 29, wherein the at least one reinforcing member is formed of polyurethane.

36. The vacuum insulating panel according to claim 29, wherein the powder material is selected from the group consisting of fumed silica, precipitated silica or perlite, or combinations thereof.

37. The vacuum insulating panel according to claim 29 wherein the insulating core has an average pore size of from 50 nm to 350 nm.

38. The vacuum insulating panel according to claim 29, wherein the insulating core is constructed from a material comprising fumed silica and wherein the density of the said insulating core within the vacuum insulating panel is of from 100 kg/m.sup.3 to 160 kg/m.sup.3 or from 130 kg/m.sup.3 to 160 kg/m.sup.3 or from 100 kg/m.sup.3 to 130 kg/m.sup.3.

39. The vacuum insulating panel according to claim 29, wherein the at least one reinforcing member is formed of a porous material having an average pore size of from 20 micron to 200 micron in diameter.

40. The vacuum insulating panel according to claim 29, wherein the thickness of the reinforcing member and the thickness of the insulating core are in a ratio of, respectively, from 1:5 to 1:20, within the vacuum insulating panel; the at least one reinforcing member comprises polyurethane and the insulating core comprises fumed silica and wherein the density of the said insulating core within the vacuum insulating panel is of from 100 kg/m.sup.3 to 160 kg/m.sup.3 for example from 100 kg/m.sup.3 to 135 kg/m.sup.3 or from 130 kg/m.sup.3 to 160 kg/m.sup.3.

41. The vacuum insulating panel according to claim 29, with a thermal conductivity value of less than 3.5 mW/mK.

42. A method for manufacturing a vacuum insulating panel, comprising: providing a porous insulating core having an upper surface and a lower surface and sides, the insulating core is constructed from a microporous insulating material formed from a powder material; arranging at least one reinforcing member on the upper or lower surface of the insulating core to reinforce the core, the reinforcing member is formed of a porous material, and is substantially rigid; the at least one reinforcing member and the insulating core form a hybrid core and the at least one reinforcing member does not form a thermal bridge across the insulating core; enveloping the hybrid core with a barrier envelope; applying a vacuum to evacuate the barrier envelope, so that the barrier envelope closely engages the insulating core and the at least one reinforcing member of the hybrid core; the density of the insulating core within the vacuum insulating panel is of from 100 kg/m.sup.3 to 160 kg/m.sup.3, and thermal conductivity of the vacuum insulating panel is in the range of from 3.0 mW/m.Math.k to 4.0 mW/m.Math.K.

43. The method according to claim 42, wherein an upper reinforcing member is arranged on the upper surface of the insulating core and a lower reinforcing member is arranged on the lower surface on the insulating core.

44. The method according to claim 42, wherein the at least one reinforcing member is formed of polyurethane.

45. The method according to claim 42, wherein the powder material is selected from the group consisting of fumed silica, precipitated silica or perlite, or combinations thereof.

46. The method accord ing to claim 45, wherein the insulating core is constructed from a material comprising fumed silica and the density of the said insulating core within the vacuum insulating panel is of from 100 kg/m.sup.3 to 160 kg/m.sup.3 for example from 100 kg/m.sup.3 to 135 kg/m.sup.3 or from 130 kg/m.sup.3 to 160 kg/m.sup.3.

47. The method according to claim 42, wherein arranging a lower reinforcing member on the lower surface of the core comprises: arranging the lower reinforcing member in a mold; filling the mold with an insulation material; and pressing the insulation material in the mold to form the insulating core.

48. The method according to claim 42, wherein arranging an upper reinforcing member on the upper surface of the core comprises: filling a mold with an insulation material; arranging the upper reinforcing member on top of the insulation material in the mold; and pressing the insulation material in the mold to form the insulating core.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0167] Embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings in which:

[0168] FIG. 1 is a cross-sectional view of a portion of a VIP according to a first embodiment of the invention.

[0169] FIG. 2 is a cross-sectional view of a portion of a VIP according to a second embodiment of the invention.

[0170] FIG. 3 is a perspective cut-away view of a VIP according to the invention. FIG. 3 clearly shows the hybrid core sandwich formed by the upper reinforcing member the lower reinforcing member and the insulating core therebetween. The cut-away view clearly depicts how the envelope, envelops the hybrid core.

[0171] FIG. 4 is a cross section view of a VIP according to the invention, which also shows the structure of the hybrid core at the sides of the VIP. FIG. 4 clearly shows the sandwich nature of the hybrid core, and in particular shows how the reinforcing layer does not wrap around the insulating core at the sides of the VIP. Accordingly, the reinforcing member does not form a thermal bridge across the insulating core.

[0172] FIG. 5 shows a perspective view of a VIP according to the invention after the application of the vacuum and sealing of the envelope, prior to trimming and folding of the edges to form the finished product. The smooth exterior of the VIP is clearly shown.

[0173] FIG. 6 shows a perspective view of a VIP having a reduced density core, but absent the reinforcing members of the present invention. The surface of the VIP is wrinkled and the edges are collapsing.

[0174] FIG. 7 shows a perspective view of the finished VIP according to the invention.

[0175] FIG. 8 is a photograph of a VIP according to the invention as described in relation to FIG. 5 above. The smooth surface of the VIP is clearly shown.

[0176] FIG. 9 is a photograph of a reduced density core VIP but absent reinforcing members, as described in relation to FIG. 6 above. The wrinkled and collapsing surface of the VIP is clearly shown.

DETAILED DESCRIPTION OF THE DRAWINGS

[0177] The FIG. 1 illustrates a cross section portion of VIP 1 according to a first embodiment of the invention in cross-section. The VIP 1 comprises an insulating core 2 having a density of 140 kg/m.sup.3 having upper 3 and lower 4 surfaces. The VIP also comprises a reinforcing member 5 of rigid polyurethane arranged on the lower surface 4 of the core 2. The reinforcing member 5 is porous and has a substantially smooth outer surface 7. Together the reinforcing member 5 and the insulating core 2 form a hybrid core 8. The reinforcing member 5 is arranges so that no thermal bridge is formed across the insulating core 2 i.e. the reinforcing member does not form a thermal bridge between upper surface 3 of the insulating core and lower surface 4 of the insulating core. The VIP further comprises a barrier envelope, optionally constructed from a barrier film 6, arranged to envelop the insulating core 2 and the reinforcing member 5 of the hybrid core 8.

[0178] The VIP 1 is manufactured by arranging a product, optionally in the form of a sheet, 5 of rigid polyurethane in a mould, filling the mould with a particulate insulation material which in the embodiment is a mixture of powder and fibres and pressing the mixture in the mould to form the insulating core 2 (which is porous and optionally microporous) having a reinforcing member 5 arranged on the lower surface 4 thereof. The insulating core 2 and the reinforcing member 5 together form a hybrid core 8; wherein the reinforcing member is arranged so that no thermal bridge is formed across the insulating core 2 i.e. the reinforcing member does not form a thermal bridge between upper surface 3 of the insulating core and lower surface 4 of the insulating core. The hybrid core 8 is then enveloped with the barrier film 6 and a vacuum is applied so that the barrier film closely engages the insulating core and the polyurethane layer 5 of the hybrid core 8. As shown in FIG. 1, when the vacuum is applied, the upper surface of the VIP is relatively rough, due to the undulating surface of the low density insulating core 2, whereas the lower surface of the VIP is relatively smooth, due to the smooth outer surface of the polyurethane sheet or reinforcing member 5.

[0179] FIG. 2 illustrates a portion of VIP 1 according to a second embodiment of the invention in cross-section. The VIP 1 comprises an insulating core 2 having a density of 130 kg/m.sup.3 having upper 3 and lower 4 surfaces. The VIP also comprises two reinforcing members 5 of rigid polyurethane arranged on the upper 3 and lower 4 surfaces of the core 2. The reinforcing members 5 are arranged so as not to form a thermal bridge across the insulating core 2 i.e. the reinforcing members do not form a thermal bridge between upper surface 3 of the insulating core and lower surface 4 of the insulating core. The layers 5 are porous and each has substantially smooth outer surface 7. The VIP further comprises a barrier film 6, arranged to envelop the insulating core 2 and the reinforcing members 5 of the hybrid core 8.

[0180] The dimensions of the VIP in FIG. 1 are 300 mm×300 mm×30 mm.

[0181] In the exemplified embodiments, the reinforcing member 5 is a sheet of polyurethane foam, having a thickness of 1 to 5 mm, for example the thickness may be 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 5.0 mm. The reinforcing member may have a density of 30-80 kg/m.sup.3, and an open cell content of about 90%. The polyurethane foam reinforcing member has a compressive strength of 95-150 kPa.

[0182] The insulating core is constructed from an insulation material mixture comprising fumed silica (50-90% w/w), opacifier (5-40% w/w), and fibres (0-20% w/w). The density of the insulating core within the VIP of FIG. 1 is 140 kg/m.sup.3, whereas the density of the insulating core within the VIP of FIG. 2 is 130 kg/m.sup.3.

[0183] The initial thermal conductivity of the VIP in FIG. 1 is 3.4 mW/mK, whereas the initial thermal conductivity of the VIP in FIG. 2 is 3.6 mW/mK.

[0184] The thickness of the reinforcing member in the VIP of FIG. 1 is approximately 2 mm and the insulating core in the VIP of FIG. 1 is approximately 2 mm. The thickness of reinforcing member in the VIP of FIG. 2 is approximately 2 mm and the thickness of the insulating core in the VIP of FIG. 2 is approximately 26 mm.

[0185] The vacuum pressure within the VIPs of the invention is between 0.01 kPa (0.1 mBar) and 0.40 kPa (4 mBar).

[0186] The hybrid cores of the VIPs of the present invention may be enveloped with a barrier envelope, optionally in the form of a barrier film, as described in GB2492876 and as shown in FIGS. 4 and 5 therein.

[0187] FIG. 3 is a perspective cut-away view of a VIP 1 according to the invention. The VIP shown in FIG. 3 comprises both an upper reinforcing member 5 and a lower reinforcing member 5 and has the same construction as the VIP shown in FIG. 2. FIG. 3 clearly shows the hybrid core sandwich formed by the upper reinforcing member 5 the lower reinforcing member 5 and the insulating core 2 therebetween. The cut-away view clearly depicts how the barrier film (or envelope) 6, envelops the hybrid core.

[0188] FIG. 4 is a cross section view of a VIP 1 according to the invention, which also shows the structure of the hybrid core at the sides of the VIP. The VIP 1 comprises an insulating core 2 having a density of 130 kg/m.sup.3 having upper 3 and lower 4 surfaces. The VIP also comprises two reinforcing members 5 of rigid polyurethane arranged on the upper 3 and lower 4 surfaces of the core 2. The reinforcing members 5 are arranged so as not to form a thermal bridge across the insulating core 2 i.e. the reinforcing members do not form a thermal bridge between upper surface 3 of the insulating core and lower surface 4 of the insulating core. The layers 5 are porous and each has substantially smooth outer surface 7. The VIP further comprises a barrier film 6, arranged to envelop the insulating core 2 and the reinforcing members 5 of the hybrid core 8. FIG. 4 clearly shows the sandwich nature of the hybrid core, in particular 102 shows how the reinforcing layer does not wrap around the insulating core at the sides of the VIP. Accordingly, the reinforcing member 5 does not form a thermal bridge across the insulating core 2.

[0189] FIG. 5 shows a perspective view of a VIP 201 according to the invention after the application of the vacuum and sealing of the barrier film (or envelope), prior to trimming and folding of the edges to form the finished product. The smooth exterior of the VIP is clearly shown. This smooth surface affords the VIPs of the present invention a better contact surface for adhesion of the VIP to other surfaces in use. The VIP shown in FIG. 5 may have the same construction as the VIP of FIG. 1 or the VIP of FIG. 2.

[0190] FIG. 6 shows a perspective view of a VIP 202 having a reduced density core, but absent the reinforcing members of the present invention. The surface of the VIP is wrinkled and the edges are collapsing. VIP 202 is not commercially acceptable. Because of the collapsing surfaces and edges, the VIP does not pack well.

[0191] FIG. 7 shows a perspective view of the finished VIP according to the invention.

[0192] FIG. 8 is a photograph of a VIP according to the invention as described in relation to FIG. 5 above. The smooth surface of the VIP is clearly shown.

[0193] FIG. 9 is a photograph of a reduced density core VIP but absent reinforcing members, as described in relation to FIG. 6 above. The wrinkled and collapsing surface of the VIP is clearly shown. VIPs having a wrinkled collapsing surface are commercially unacceptable. In addition, as a result of the wrinkling they do not pack well.

[0194] As outlined above, the hybrid core may be encased in a in an air permeable cover prior to encasing the hybrid core in the flexible envelope. For example, the air permeable cover may be selected from a non-woven PET fleece or perforated shrink wrap.

[0195] The words “comprises/comprising” and the words “having/including” when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0196] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.