Synthetic fibre felt

The filters used for gas cleaning separate the solid particles by a combination of impingement and filtration the pore sizes in the filter media used are too large simply to filter out the particles. The separating action relies on the precoating of the filter medium by the first particles separated which are separated by impingement on the filter medium fibres. Woven or felted cloths of cotton and various synthetic fibres are commonly used as the filter media. Glass-fibre mats and paper filter elements are also used. 

Cartridge filters are used widely throu out process industries in the clarification of liquids. The media used include yams, papers, felts, binder-fi ee and resin-bonded fibres, synthetic fibres, woven wire, sintered metal powders and fibres, ceramics, etc. The inclusion of membraneous materials. Chapter 10, in cartridge constructions has extended the range of application of these ubiquitous dements so that partides firom approximate 500 pm down to 0.1 pm are separated. 

Another way to protect the iimer, support component of upholstery is the use of barrier materials in the form of non-flammable interlayers placed between a covering fabric and the filling material. Woven and non-woven fabrics as well as felt made from natural fibres (e.g., cotton, flax and hemp) and their blends with flame retarded synthetic fibres, can be used. 

Woollen felt is probably the oldest form of textile, and for many years was the only practical nonwoven fabric, produced by the combined action of moisture and heat on carded wool fibres. The development first of a strong adhesive-bonded felt, and then of the multiplicity of forms of dry-laid synthetic fibres, has transformed the spectrum of nonwoven media, both in format and basic material. 

Modem felts are produced from synthetic fibres or mktures of synthetic and natural fibres, bonded with adhesive or held together mechanically, with close control of manufacture to yield consistent density, pore size and mesh geometry, so that the cut-off performance is reasonably predictable. The structure of felts is considerably more open than papers so that whilst filtering in greater depth, specific resistance is lower and high rates of flow can be achieved with smaller element areas and low pressure drop. 

The pad filter (often called a cassette) is a special case of the range of panel filters, all of which are made in standard sizes, to fit air-conditioning installations. The pad, as its name implies, is a thick flat sheet of fibrous filter medium, made either by wet-laying (as in paper) or by dry-laying (as in a felt). Felt pads are the most common, and they can be either as-laid, which would normally be the case for natural fibres such as cotton or wool, or needle-punched, for synthetic fibres. 

Panel filters can be made from any material that can be pleated, without cracking along the fold cellulose or glass paper, fine wire cloth, woven fabrics, nonwoven fabrics of all kinds (felts, spunbonds, meltblown) and membranes. Charcoal cloth can also be used, provided that it is pleated before charring. Synthetic fibre media are most common, having shown themselves well suited to the ventilation of a wide variety of buildings domestic, commercial, institutional and industrial. 

A fabric made by uniting a mass of staple fibres into a continuous sheet by using the adhesive properties of a bonding agent, usually rubber latex, either natural or synthetic. In textile technology the term is applied to fabrics which are not woven, such as felted fabrics. Non-woven fabrics are now being termed bonded fabrics. 

A series of parallel spines (current collectors) are connected at the upper end to a common connector bar (connector bus) which ends with a plate lug. The spines are positioned in the centre of tubes made of either woven, braided or felt acid-resistant glass wool or synthetic organic fibres. Depending on their shape (cross-sectional geometry), tubes may be cylindrical (round), elliptical (oval) or rectangular (square). Cylindrical tubes with the spines (current... 

Typical materials include woven fibres, metal screens or fabrics, pressed felt or cotton batting, sheets of synthetic polymers, paper, sand, coal, silica porcelain and many more. Filtration equipment is equally diverse for both batch and continuous processing [23]. 

The elements are most commonly in the fonn of a bag, closed at the lower end and sealed to the support plate at the top. A sleeve stracture is also used, sealed to its support cage at both ends. Filter pockets may be used instead of bags, and so are several other element designs particular to certain applications. The filter media can be rigid or flexible, and have employed almost every type of material from which filter media are made woven yams (natural or synthetic), felts and needlefelts, pleated sheet, spunbonded polymers and other forms of meltspnn materials, glass fibre, metallic fibre or wire, sintered powders and ceranucs. 

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