Non-woven filter

An up-date of the status of EB curing of carbon fiber composites was presented by A. Berejka. Developments proven successful for aerospace applications are now being seriously scrutinized for automotive use. The diversity of proven uses of radiation grafting for uses in batteries, porous film and non-woven filters, and release coated films and papers was also presented. Opportunities for use of grafting in biomedical applications, composites technology, and fuel cell membrane development were also discussed. 

Filter elements may be of the 5-micron, woven mesh, micronic, porous metal, or magnetic type. The micronic and 5-micron elements have non-cleanable filter media and are disposed of when they are removed. Porous metal, woven mesh and magnetic filter elements are usually designed to be cleaned and reused. 

Asahi Medical Co. (Japan) developed Sepacell-PL filter as a device for removing white blood cells from whole blood [119, 120], Sepacell-PL is a non-woven fabric (PE or PET), coated with a copolymer of HEMA with die-thylaminoethyl methacrylate (e.g. in 5 mole%). It is noticeable that platelets in the blood can pass through the filter without suffering any damage during the filtration processes, owing to the presence of the amino group. 

Common uses for polyester resins are reinforced plastics automotive parts boat hulls foams encapsulation of electrical equipment protective coatings ducts flues and other structural applications low pressure laminates magnetic tapes piping bottles non-woven disposable filters and low-temperature mortars. 

A process of obtaining a cellulosic wet sheet and a membrane and equipment for their manufacture Development of high performance leukocyte reduction filters based on ultra-fine non-woven fabric Development of a novel adsorbent based on bacterial cellulose for adsorption of rare earth metals Metallization of bacterial cellulose for electrical and electronic device manufacture... 

Latex bonded non-woven polyester Batting Air Filters Carpet underlayment Insulation Textile backing Roof coatings Bedding... 

Non-woven media in the form of felts and compressed cellulose pulps, are used for clarification by depth filtration. Unless carefully prepared, they have the disadvantage of losing fibrous material from the downstream side of the filter. The application of sheet media has been discussed earlier. High wet strength is conferred on paper sheets by resin impregnation. An alternative technique employs asbestos fibers supported in a cellulose framework. 

The main features of purification filters based on ion exdiange fibrous materials are high sorption capacity and purification degree, low aerodynamic resistance, and efficient regeneration. As studies have shown [4 ], at a gas,flow rate of 0.1 m/s in a dense layer of a non-woven material, the length of a working layer is 2 mm which makes it possible to use filtering cloths of 10—20 mm thickness. The area of the filter is 20 m per 1 m of operation volume which corresponds to specific output, 7 10 m /h of purified air. The aerodynamic resistance of filters in this case does not exceed 20 Pa. 

The influence of fibers on the strength, structure, and characteristics of agglomerates was discussed in Section 5.1.2. The binding mechanism interlocking bonds (see Section 5.1.1), the intertwining of fibers and threads, is also used directly to produce agglomerates by producing non-wovens, felts, filters, webs, paper, etc. 

The non-woven mats were able to retain up to 60% of the initial surface potential after several days of annealing at temperatures up to 140 °C. This is higher than in the case of corona-charged compact films. These properties make the materials ideal candidates for electret filter and sensing applications [55]. 

The above section has concentrated on the use of woven filter media in pressure filters. It will be realised that a vast interest lies in the application of non woven, random fibre filter media to gas and liquid filtration systems [Fletcher, 1982], Plate and fl ame... 

A novel water pmification filter has been in development over the past seven years. The first version is a pleated depth filter cartridge that has high particle retention efficiency at moderate to high flowrates, while also having a high particle retention capacity. The filter media is also sold as non-woven media by Ahlstrom imder the tradename Disrupter . Argonide manufactures the filter cartridge from Disraptor media. 

The filter s active component is a nano alumina monohydrate fiber, only 2 nm in diameter and with an external surface area of 500 m /g. It has been identified as crystalline boehmite (AlOOH) using x-ray diffraction. The isoelectric point of raw fibers is approximately 11.1 (7). Particles with an electronegative charge are attracted and retained by the nano alumina. The nano alumina is bonded by a proprietary process to a microglass fiber that serves as a scaffold in a non-woven media. 

Fibrous structural media containing GAC are used extensively as filters. Compared to a granular bed such as GAC, a non-woven fibrous structure minimizes channeling, allows significant filter design variations, and can be manufactured by low cost paper manufacture methods. 

A non-woven electropositive filter media has been shown to be effective in filtering bacteria and vims. It is currently being manufactured and is commercialized in the form of media, as cartridges and as filter discs. 

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