Reverse plain Dutch weave

For filtration purposes, the most widely used forms of woven wire are the Dutch or hollander weaves, wherein the warp and weft are of different diameter, generally with a corresponding difference in the relative numbers of warp and weft wires. If the warp wires are thicker, the result is the plain Dutch weave the alternative is for the weft wires to be the thicker, giving the reverse plain Dutch weave . 

Reverse plain Dutch weave is similar except that the thicker wire is in the weft (Figure 2.12). Reverse plain Dutch weave is substantially stronger, and is in fact the strongest filter weave in commercial production as a result, coupled with its good flow characteristics and high dirt-holding capacity, it is widely used industrially. 

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...

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... 

PRD Plain Reverse Dutch weave. See weave patterns. 

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). 

There are several available weaves of woven wire. Some of these weaves lead the product to be called woven fabric. The basic types of weaves of wire cloth, which are woven for filtration purposes, are plain, twilled, plain Dutch, twilled Dutch, plain reverse Dutch, duplex (twin warp) plain Dutch, Betamesh and braided (basket of multibraid)—see Figure 8.1. 

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. 

Filter fabrics are mainly woven in four common weaves plain, twill, plain reverse Dutch and satin. The first three are overlaps from wire cloth weaves but may have slightly different characteristics when put into the framework of woven non-metallic cloth. The weaves will not be detailed again here. The fourth weave is the satin weave where the shute (or warp) fibre passes over several warp (or shute) fibres, then under one in an alternating pattern. Figure 8.3 shows an over three-under one pattern for the satin weave (three shaft satin) see also Table 8.2. 

Even though fibres of the above synthetic materials can be woven multifilament or monofilament, there is a trend towards the use of monofilament filter fabrics. This is so mainly because in years past it was very difficult to weave monofilaments in the fine, low-micron retention areas. Today, monofilament filter fabrics can be woven twilled down to 6 pm and plain reverse Dutch down to 14 pm. Further finishing (shrinking and calendering) can bring the particle removal rating down to the 1 pm area. 

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