Knitted structures

Lucas and Porter (U.S. Patent 3,370,401, 1967) developed a fiber-bed scrubber in which the gas and scrubbing liquid flow vertically upward through a fiber bed (Fig. 17-55). The beds tested were composed of knitted structures made from fibers with diameters ranging From 89 to 406 [Lm. Lucas and Porter reported that the fiber-bed scrubber gave substantially higher efficiencies than did venturi-type scrubbers tested with the same dust at the same gas pressure drop. In similar experiments, Semrau (Semrau and Lunn, op. cit.) also found that a fiber-bed contactor made with random-packed steel-wool fibers gave higher efficiencies than an orifice contactor. However, there... 

In order to define such differences, we must first show how these states differ physically from one another. We will start with gases, then liquids cmd finally solids. As we shall see, the major difference between these states is a matter of energy, the solid having the least energy of all. Gaseous molecules are free to roam, whereas molecules in the liquid state are bound together and molecules in the solid state are bound and ordered into a tight-knit structure. 

Fib er-Bed Scrubbers Fibrous-bed structures are sometimes used as gas-liquid contactors, with cocurrent flow of the gas and liquid streams. In such contactors, both scrubbing (particle deposition on droplets) and filtration (particle deposition on fibers) may take place. If only mists are to be collected, small fibers may be used, but if solid particles are present, the use of fiber beds is limited by the tendency of the beds to plug. For dust-collection service, the fiber bed must be composed of coarse fibers and have a high void fraction, so as to minimize the tendency to plug. The fiber bed may be made from metal or plastic fibers in the form of knitted structures, multiple layers of screens, or random-packed fibers. However, the bed must have sufficient dimensional stability so that it will not be compacted during operation. 

Knitted fabric construction characterization is discussed in ASTM D3887. Characterization of knitted fabrics includes yield (area per weight), width, length, and yam count (number of courses and wales per unit length). The type of knit is also specified, eg, warp knit or weft knit. Yam analysis may be difficult on account of problems in raveling individual yams from the knitted structure, particularly warp knits. 

For the knitted structure, the opposite effect is observed. Because of its elastic structure, the knitted electrode will adapt to the shape of the holders and fittings used in the electrochemical cell. At the surface of the knitted... 

In Sections 24.3 and 24.5 the flammability and fire resistance of individual fiber/fabric type are discussed. However, as also discussed before, the fire resistance of a fabric not only depends upon the nature of components and the FR treatments applied, but also on fabric area density, construction, air permeability, and moisture content. Nonwovens, for example, will have superior properties to woven or knitted structure, even if all other variables are kept the same.93 The air entrapped within the interstices of any fabric structure and between layers of fabrics within a garment assembly provides the real thermal insulation. For effective thermal and fire resistance in a fabric structure, these insulating air domains need to be maintained.22 In general, for protective clothing and fire-block materials, for best performance multilayered fabric structures are employed. The assembly structures can be engineered to maximize their performance. It is beyond the scope of this chapter to go into details of these composite structures hence the reader is referred to the literature on specified applications and products available. 

The traditional machines used for mercerizing woven fabrics are inadequate to treat circular knit fabrics. Owing to knit structure, such fabrics are easily deformed, distorted and extended on stretching during mercerization and washing. These dis-... 

Nielsen and Edrusick [29] evaluated the effect of five kinds of knit structures, all made from 100% polypropylene were evaluated. On subjects exercising for 40 minutes at 5°C followed by 20 minutes at rest, and then repeated. The thickest knit, a fleece, caused the greatest total sweat production, retained the most moisture, and wetted skin the most. They stated that the hydrophobic polypropylene prevented extensive sweat accumulation in the underwear (10 to22%) causing the sweat to accumulate in the outer garments. 

Pavko-Cuden, A., Hladruk, A., Sluga, F., 2013. Loop length of plain single weft knitted structure with elastane. J. Eng. Fibers Fabr. 8 (2), 110-120. 

Figure 5.3 Deformation of the weft-knitted structure in weft (horizontal) and warp (vertical) directions.

Elimination of seams from the shoe upper and ability to seamlessly incorporate various knitted structures into the upper piece offer added flexibility, reduced weight, foot conformity and mapping of the upper part of the foot, according to the required support and flexibility, as well as to the thermo-physiological requirements of the foot such as ventilation, thermal transfer and breathability. It is also possible, similarly to the garment circular machines described above, to vary the stitch length of the knitted... 

The impact of seamless sports apparel manufacturing methods has grown with the development of machinery that allows more flexible and complex knitting structures greater sophistication in use of body zoning the use of more fibre and yam combinations and the in-roads made by this manufacturing method into areas such as footwear and hosiery for sportswear. 

Birrfelder, P., Dorrestijn, M., Roth, C., Rossi, R.M., 2013. Effect of fiber count and knit structure on intra- and inter-yam transport of liquid water. Text. Res. J. 83, 1477-1488. 

Dias, T., DeUaimburewatte, G.B., 2007. The influence of moisture content on the thermal conductivity of a knitted structure. Meas. Sci. Technol. 18, 1304-1314. 

Nielsen, R., Endrusick, T.L., 1990. Thermoregulatory responses to intermittent exercise are influenced by knit structure of underwear. Eur. J. Appl. Physiol. Occup. Physiol. 60, 15-25. 

Three basic types of construction are found in fabric dust collectors woven fabrics, nonwovens, and knitted structures. The first two are produced in flat form and will require (1) slitting to appropriate width, and (2) converting into tubular sleeves, whereas the knitted fabrics may be produced directly in a tubular form. 

Anand SC, Lawton PJ. The development of knitted structures for filtration. J Textile Inst 1991 82(3) 297. 

Anand SC, Lawton PJ, Barlow G, Hardman E. Application of Knitted Structures in Dust Filtration. Manchester Filtration Society Meeting 15 May 1990. 

Vascular grafts are used in surgery to replace damaged thick arteries or veins 6 mm, 8 mm, or 1 cm in diameter. Commercially available vascular grafts are produced from polyester (e.g. Dacron) or PTFE (e.g. Teflon) with either woven or knitted structures... 

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