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Fiber-processing filtration

The same basic spinning process is used for the preparation of hollow fiber membranes, which have an outer diameter of 50 to 100 jum. In hollow fiber membranes, the selective layer is on the outside of the fibers, which are installed as a bundle of several thousand fibers in a half loop with the free ends potted with an epoxy resin in a pressure tube as indicated in Figure 1.33 (f). The feed solution is introduced around the outside of the hollow fibers. The filtrate passes through the fiber walls and flows up the bore to the open end of the fibers at the epoxy head. [Pg.53]

TREATABILITY/REMOVABILITY Process, Removable Range (%), Avg. Achievable Cone. (10 fibers/L)) Filtration, 90->99, 470 Sedimentation, 80->99, 3,000 Sedimentation... [Pg.237]

Fiber processing development Unusual plastic fibers such as polyolefin fibers are produced by a spurted or melt-blown spinning technique. A variety of directly formed nonwovens with excellent filtration characteristics is produced. Original development was by... [Pg.89]

Vibratory membrane techniques are characterized by vibrating the membrane at certain frequency and amplitude. The vibration techniques used in the membrane filtration enhancement include the high-frequency circular vibration, for example, vibratory shear-enhanced process (VSFP), and low-frequency vibration for hollow fiber membrane filtration. [Pg.278]

Regulatory FDA 21CFR 169.179, 182.2122(2% max.), GRAS Europe listed UK approved Trade Name Synonyms PMF Fiber 204 t[Pall Process Filtration]... [Pg.180]

Aqueous media, such as emulsion, suspension, and dispersion polymerization, are by far the most widely used in the acryUc fiber industry. Water acts as a convenient heat-transfer and cooling medium and the polymer is easily recovered by filtration or centrifugation. Fiber producers that use aqueous solutions of thiocyanate or zinc chloride as the solvent for the polymer have an additional benefit. In such cases the reaction medium can be converted directiy to dope to save the costs of polymer recovery. Aqueous emulsions are less common. This type of process is used primarily for modacryUc compositions, such as Dynel. Even in such processes the emulsifier is used at very low levels, giving a polymerization medium with characteristics of both a suspension and a tme emulsion. [Pg.279]

The dry-extmsion process consists of four operations dissolution of the polymer in a volatile solvent filtration of the solution to remove insoluble matter extmsion of the solution to form fibers and lubrication, yam formation, and packaging. [Pg.296]

Filtration of viscose is not a straightforward chemical engineering process. The solution of cellulose xanthate contains some easy-to-deal-with undissolved pulp fibers, but also some gel-like material which is retarded rather than removed by the filters. The viscose is unstable and tends to form more gel as it ages. Its flow characteristics make the material close to the walls of any vessel or pipe move more slowly, get older, and gel more than the mainstream viscose. So while filtration can hold back gels arising from incomplete mixing, new gels can form in the pipework after the filters. [Pg.347]

Fibers of different diameters, lengths, shapes, and densities fractionate, or break up, when processed together in airstreams. This fractionation results in the formation of webs with different top and bottom surface characteristics, as well as varying density and porosity gradients. Such stmctures ate well suited for many filtration appHcations. [Pg.151]

Filtration. The filtration process depends on the physical retardation of microorganisms from a fluid by a filter membrane or similarly effective medium. The effectiveness of this process is also influenced by the bioburden (6). HoUow-fiber membranes (qv) are most often employed. The resultant... [Pg.409]


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