Dutch weaves

The other type of common weave is called a Dutch weave. Table 1 provides a conversion chart between the two types of weave and micron ratings. Discussions that follow focus on different types of common flexible filter media. 

Dutch Weave Square Weave Micron Rating... 

What is the micron rating of a 50 X 250 Dutch weave filter cloth ... 

PRD Plain Reverse Dutch weave. See weave patterns. 

DUTCH TWILL PLAIN OK SQUARE DUTCH WEAVE... 

Grootenhuis (Proc. Inst. Mech. Eng. [London], A168, 837—846 [1954]) presents data which indicate that for a series of screens, the total pressure drop equals the number of screens times the pressure drop for one screen, and is not affected by the spacing between screens or their orientation with respect to one another, and presents a correlation for frictional losses across plain square-mesh screens and sintered gauzes. Armour and Cannon (AIChE J., 14,415-420 [1968]) give a correlation based on a packed bed model for plain, twill, and dutch weaves. For losses through monofilament fabrics see Pedersen (Filtr. Sep., 11, 586-589 [1975]). For screens Inclined at an angle 0, use the normal velocity component V ... 

Septa may be made of metal, natural, or synthetic yams. Plain, twill, and dutch weaves are available in the metal cloths. In the natural and synthetic fiber cloths, plain, twill, chain, and satin weaves in monofilament, multifilament, and staple yams have been used. 

There are many types of weaving patterns for woven fabrics and the four basic types are plain weave, twill weave, satin weave, and plain reverse Dutch weave (Svarovsky 1990) as shown in Figure 22.66. The filtration performances of the four types of weaves are shown in Table 22.13. 

Note PRD, plain reverse Dutch weave. Source From Purchas (1967). 

Other patented (nonporous) methods to provide support for thin membranes include the cylindrical screens for supporting thin membrane tubes of Bonnet [22], the metal gauze of Juda and Novack [23], the Dutch weave wire netting of Yamauchi, et al. [24], the circular screens of Bonnet [25], the perforated conduits of Eguchi et al. [26], the helical wires of Hollister and Stiles [27], the square perforations of Prolss [28], the corrugated screens of Iniotakis et al. [29], and the var-... 

All interesting variant is where the diameter of the warp yam is different fiom the weft, in the production of Dutch weaves of strong constmction. A Dutch weave produces two openings or pores in the bric, one on the sur ce between parallel yams and a second, triangular pore in the plane of the cloth. These cloths produce excellent performances in the separation of solid, crystalline materials, but are less successfiil in filtering slimy colloids i diidi can lodge in the triangular pores. 

A relatively new type of closed twill weave is available for colloidal separations. Whilst such fabrics have lower clean permeabilrties than plain or Dutch weaves, they are more easily cleaned and withstand heavy use. 

Two basic forms of twilled Dutch weave are produced by combinations of warp and weft wires of different diameters. The use of heavy warp wires (Dutch twill weave) permits production of fine grades of woven wire cloths which have very smooth surfaces on both sides, but these cloths have a relatively high flow resistance. With heavy weft wires (reverse Dutch twill weave) the flow resistance is less but there is a corresponding decrease in micron retention characteristics and both sides of the cloth have rougher surfaces. 

Dutch weave Warp and weft wires of different 6... 

Dutch weave section than diameter of wires laid in the other direction ... 

Twill Dutch weave The finest wires are overlapped 9... 

The liquid is passed under centrifugal force through a filter medium or perforated plate. Filtration occurs as the liquid passes through the interstices of the solid particles that have built up on the medium surface. Depending upon the degree of separation desired, fdter media can be a filter fabric of twilled weave, dutch weave or plain weave in either stainless steel or synthetic fibre. 

Figure 8.1 Different types of weaves, (a) Plain square weave, (b) Plain twilled weave, (c) Plain Dutch weave, (d) Twilled Dutch weave, (e) Reverse Dutch weave, (f) Duplex (twin warp) plain Dutch weave, (g) Betamesh Dutch weave, (h) Basket (braided or multibraid) weave...

With a twilled Dutch weave the mesh count of the warp wires is much lower than that of the shute. The shute wires pass over two and under two wires in both directions. They are pushed together such that one shute wire is on top of the next one, which is directly under the warp wire. This yields... 

The Twilled Square weave is the second most complex style the warp and shute wires are also the same diameter, but each shute wires passes over two warp wires before going under the next two warp wires. The pattern then repeats. The Plain Dutch weave has the same pattern as the Plain Square, but the warp wires are larger in diameter than the shute wires, which creates smaller pore sizes. The Reverse Dutch weave is the inverse of the Plain Dutch the shute wires are larger than the warp wires. Lastly, the most complex screen... 

Table 3.2 lists values for warp and shute wire diameters, along with calculated values for the screen thickness, surface area to volume ratio, eind void fraction, for edl available screens in the literature. Values of d and ds are obtained from the literature (Armour and Cannon, 1968 Paynter, 1970 Heckman, 1971 Burge and Blackmon, 1973b Cady, 1973) or from industry, where available. Tortuosity values are 1.0 for Plain Square and Twilled Square weaves and 1.3 for Reverse Twill, Plain Dutch, and Twilled Dutch weaves. 

Table 3.5 Effective Wicking Diameters for Several Dutch Twill and Plain Dutch Weaves...

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