Monofilament Cloth Permeability

In the monofUament area much more success in correlating permeability with cloth structure has followed the suggestions of Pedersen [1969], who adopted orifice-type formulae to correlate pressure-drop-flow information for various weave patt s. 

The discharge coeffident was anticipated to be a function of the Reynolds number within the fabric. 

In order to correlate the 2/1 twill and 5/1 sateen data it is necessary to define a flow ceU , which is repeated in the pattern of the cloth. In the case depicted (2/1 twill) the cell is made up to 6 twill pores and 3 plain pores a wei ting procedures is proposed so that  

S = Sateen T = Twill dj, Calculated pore size from dp = 44/iT ec,pc = end count and pick count respectively. 

The above cloths were supplied by P S Filtration Ltd, Hashngden U.K. 

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In selecting cloths made from synthetic materials, one must account for the fact that staple cloths provide a good retentivity of solid particles due to the short hairs on their surface. However, cake removal is often difficult from these cloths - more than from cloths of polyfilament and, especially, monofilament fibers. The type of fiber weave and pore size determine the degree of retentivity and permeability. The objective of the process, and the properties of particles, suspension and cake should be accounted for. The cloth selected in this maimer should be confirmed or corrected by laboratory tests. Such tests can be performed on a single filter. These tests, however, provide no information on progressive pore plugging and cloth wear. However, they do provide indications of expected filtrate pureness, capacity and final cake wetness. 

In multifilament cloths, fluid flow may occur through < around the permeable yams. The degree of this flow division inter-yam or intra-yam has been drown to erqrlain certain dyeing characteristics of such cloths [McGregor, 1965]. If we define Bo as the permeability of the porous yams, and Bi as the permeability of the cloth if the yam were solid, i.e. monofilament, it may be drown that ... 

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