Filtration abrasion resistance

Outstanding chemical resistance, serving industrial filtration High abrasion resistance for floor covering, upholstery, and hosiery Insensitive to water, giving dimensional stability and fabric dryness in contact with the skin... 

Without losing sight of filtration requirements, the media manufacturer must also take account of the physical forces that will be imposed on the fabric by the equipment itself in particular, the effect that these forces will have on the fabric s resistance to stretch, its resistance to flexing, or its abrasion resistance, the last in this instance is through contact with rough, possibly corroded metal surfaces. In some cases, special reinforcement patches have to be stitched to the cloth during fabrication to avert potential abrasion damage inflicted by the filter. 

Media made from metals have already been mentioned, in Section 2C, in the form of sheets and tubes made from metal fibres and powders, usually sintered together to retain their structure. By far the greatest amount of filter media made from metal, however, is in the form either of woven wire or perforated sheets, which are covered in this part of Section 2, with the conmaon features of high strength, and corrosion and abrasion resistance conveyed by the basic material of construction. The other conunon feature, of great importance to their use for filtration, is that... 

Vacuum filtration has many advantages, not the least being the fact that the feed slurry, often containing abrasive solids in a corrosive liquid, can be delivered by gravity flow or by low pressure pumps which need only to overcome the resistance in the feed pipework. In addition, vacuum filtration equipment does not have to withstand high pressures... 

Costs of adsorption are limited by crushing resistance and abrasive strength of carbons. Losses of carbon may occur either in the filtration or regeneration process. Economical aspects limit losses of regeneration to the range of 2—5%. 

The abrasive forces in this context arise from the shape and the nature of the particles in the slurry. Materials with hard, sharp quartz-like edges may lead to internal abrasion, the breakage of fibres and filaments and ultimately a weak point, and possibly a pinhole in the fabric. Being the point of the lowest resistance to flow, enlargement of such a hole then follows (Fig. 3.15), eventually resulting in excessive solids in the filtrate. The filter fabric should therefore be designed, as far as possible, to withstand the impact of such forces. This may be achieved by appropriate yam and fabric constmc-tion, ideally manufactured from the toughest polymer consistent with the chemical conditions in the application. 

Having determined the preferred type of polymer and identified the various filtration requirements, of equal importance is the need to ensure that the fabric is capable of providing trouble-free performance on the equipment itself. In this respect it should provide (1) resistance to stretch (2) resistance to flex fatigne and (3) resistance to the abrasive forces that may be present on the filter itself. 

The screen-bowl decanter is a basic decanter with an extra cylindrical section attached to the end of the beach. This extra cylindrical section is perforated with a bar screen fitted on the inside wall. The cake is scrolled from the beach and over the screen to undergo further dewatering by filtration. Some rinsing may be added to the screen. The conveyor itself will be extended with a cylindrical section to perform the scrolling over the screen. This decanter can be built in co-current and countercurrent format, but has a narrow range of applications. It has been used in the low-temperature separation of para-xylene, and in coal washeries. On abrasive applications the bar screen must be resistant to erosion. Hard surfaced and carbide variants of bar screen have been used for such applications. 

PU is a versatile class of thermoplastic polymer that possesses a range of excellent properties, such as excellent elastomeric property, resistance to abrasion, and high durability [42-44]. Sambaer et al. [45] proposed a new approach to create a simple 3D nanofiber membrane model based on the real structure features of PU membranes. The slip/transition/free molecular flow regime, particle-flber interactions, air/particle slip, sieve, and homogenous flow fleld have been considered in this full 3D particle filtration model (Fig. 12.5a). They suggested that in the force... 

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