| 摘要 |
1354414 Non-woven fabrics; apparatus for making non-woven fabrics UNIVERSAL OIL PRODUCTS CO 12 May 1971 [13 May 1970] 14383/71 Headings D1K D1R D2A and D2B [Also in Division Bl] The fibre density of a woven or non-woven fibrous layer 7" of uniform thickness varies in the longitudinal direction. Preferably the density is constant for any transverse section. The density may vary smoothly and steadily in the longitudinal direction from the high density end to the low density end, an area of high density may be linked to an area of low density by an intermediate area of progressively changing density or the area of high density may comprise the middle of the layer. The layer may be in tubular form. The layer is used to control the flow of fluid. Thus in the inlet section 4" of chamber 1" the pressure exerted by liquid entering from conduit 2 is greatest at side 8 of fibrous layer 7". Hence an appropriate decrease in the density of layer 7" from side 8 to side 9 will produce a uniform flow of fluid through the fibrous layer. If inlet 11 is used the fibre density should be highest in the centre of layer 7". Alternatively layer 7" may have a density variation designed to produce non-uniform flow. The fibres may be impregnated with catalyst or may themselves act as catalyst and/or the layer may serve as a filter or molecular sieve. The fibres may be glass, aluminasilica, wool, cotton or synthetic polymer. In the embodiment of Fig. 2 a filament or yarn 20 is wound on rotating mandrel 28. A non-uniform density of the tubular product is obtained by varying the speed of guide means 20. The fibrous layer may comprise one to four woven layers in which the spacing of the warp (or weft) varies steadily (Fig. 3, not shown). In a further embodiment a loose layer of fibres (67, Figs. 4a, 4b, not shown) having more fibres at one end than the other is pressed to uniform thickness between two plates. A binder may be applied to the layer or the plates, if provided with perforations, may be used to maintain the integrity of the fibrous layer whilst it contacts the fluid flow. In a non-illustrated embodiment the fibrous layer is formed by air laying fibres onto a foraminous support to which a non-uniform pressure drop is applied. In the embodiment of Figure 5 a slurry of fibres is deposited by suction upon foraminous endless belt 99. Either the degree of porosity varies across the width of the belt or the top of the vacumn chamber 96 has perforations (110, Fig. 6, not shown) spaced at a greater distance apart at one end (111) than at the other end (112). The lip 92 of reservoir 91 is arranged so that more slurry is applied to the side of belt 99 to which the greater suction is applied. A mat of uniform thickness and variable density is thus produced. |
