| 摘要 |
A microporous insulation material is applied to a surface and progressively pressed, in a number of stages, to a smaller, uniform thickness. The continuous sheet (30, figure 1) of compressed micro-porous insulation material is cut (36, figure 1) to a desired size to provide an insulation core (40, figures 1, 5). The insulation core is encased in a flexible envelope (50, figure 5), which is evacuated under vacuum. Preferably the microporous insulation material comprising a mixture of fumed silica, IR opacifier, and fibres is spread 70 across a lower conveyor belt 72 which is trained over rollers 73, 74. The mixture is delivered by the conveyor 72 to a pressing system, preferably comprising an upper conveyor belt 71 which is trained over rollers 75, 76. The upper roller 75 at the inlet end is located to provide a lead-in pressing action. The preferred pressing system includes upper and lower sets of nipping rollers 78, 77, each pair having an adjustable gap. The first rollers 78, 77 at the input end may be set to a gap of 25mm and the others set to gradually reduce the gap to about 20mm between the final rollers 78, 77 at the output end. Preferably an upper 80 and lower 82 fleece liners 80, 82 are led from delivery roller 81, 83 to lay between the conveyor belts 71, 72 and the insulation mixture. The fleece liners 80, 82 encase the core (40, figure 5) prior to the enveloping. |
