142 A.S. Grandison and T, J. A. Finnigan could otherwise pass through the membrane itself. On a large scale, therefore, it is only this technique when small amounts of particles are present Cross-flow MF (CMF) is a development which combines the cross-flow technique, as applied to UF and reverse osmosis, with MF CMF can be used to minimise (although it should be emphasised, not completely eradicate) the problems encountered in dead-ene MF, and thus permit the processing of fluids containing quite large amounts of suspended solids on a large scale. The advantages result from the fact that the build-up of filter cake is avoided due to the shearing effect of the feed stream flowing parallel to the membrane (Fig. 5. 1). CMf plants can be operated in the same batch or continuous modes described in Chapter 3 PERMEATE Membrane Feed FIG. 5.1. Principles of (a)'dead-end and (b)cross-tlow'filtration 5.2. 1 Membrane configurations and characteristics The geometric designs of MF membranes are the same as for UF as described in Chapter 3. Hence the module housings and ancillary equipment are also similar. Also the mem brane types are the same as for UF, i.e. cellulose and synthetic polymers(described in Chapter 3)or inorganic. It is notable that the development of inorganic membranes has been towards applications in MF rather than UF and reverse osmosis. In fact some type of inorganic membrane are only available with pore sizes in the MF range Various inorganic materials have been employed for membrane manufacture including glass, metals and compounds of aluminium, zirconium and titanium, and the geometries can vary radically from conventional membrane design The structures and methods of manufacture of inorganic membranes are described in greater detail by Rios et aL. (1989). Inorganic membranes consist of two parts-a macro porous support and the active membrane coated onto the surface. The supporting142 could otherwise pass through the membrane itself. On a large scale, therefore, it is only practicable to use this technique when small amounts of particles are present. Cross-flow MF (CMF) is a development which combines the cross-flow technique, as applied to UF and reverse osmosis, with MF. CMF can be used to minimise (although it should be emphasised, not completely eradicate) the problems encountered in dead-end MF, and thus permit the processing of fluids containing quite large amounts of suspended solids on a large scale. The advantages result from the fact that the build-up of filter cake is avoided due to the shearing effect of the feed stream flowing parallel to the membrane (Fig, 5.1). CMF plants can be operated in the same batch or continuous modes as described in Chapter 3. A, S. Grandison and T. J. A. Finnigan FEED Filter cake 0 OOOc$ O O O AP{ lo+:0 **;," ' ' ' ' L +A Membrane PERMEATE (a) 0 000 0 - 0 O O+ 0 oo -0 Ooo0 0 C+SCC++++ Concentrate 0- Feed 0 00 Ap-- - __---_ - Membrane Permeate (b) FIG. 5. I. Principles of (a) 'dead-end' and (b) 'cross-tlow' filtration. 5.2.1 Membrane configurations and characteristics The geometric designs of MF membranes are the same as for UF as described in Chapter 3. Hence the module housings and ancillary equipment are also similar. Also the mem￾brane types are the same as for UF, i.e. cellulose and synthetic polymers (described in Chapter 3) or inorganic. It is notable that the development of inorganic membranes has been towards applications in MF rather than UF and reverse osmosis. In fact some types of inorganic membrane are only available with pore sizes in the MF range. Various inorganic materials have been employed for membrane manufacture including glass, metals and compounds of aluminium, zirconium and titanium, and the geometries can vary radically from conventional membrane design. The structures and methods of manufacture of inorganic membranes are described in greater detail by Rios et al. (1989). Inorganic membranes consist of two parts-a macro￾porous support and the active membrane coated onto the surface. The supporting