Cabin air filters

Gustavsson, J. Cabin air filters Performances and requirements. SAE Conference, Detroit, Feb-ruary 1996. 

Ji, J.H., Bae, G.N., Kang, S.H., Hwang, J., 2003. Effect of particle loading on the collection performance of an electret cabin air filter for submicron aerosols. Aerosol Science 34, 1493-1504. 

PP filtering materials are used both in dry (for dust control and removal of particles including automative filtration, cabin air filters, vacuum cleaner bags, masks) and wet media (such as filters for paintings, water, chemicals, alcoholic drinks). 

Grafe et al. [62] compared the filtration performances of a composite cellu-lose/nanofiber filter and a standard (wet-laid cellulose) filter and discussed the performance of nanofiber media in a mining vehicle cabin air filter. These two kinds of filters were tested independently on a Caterpillar 992G wheel loader, mounted with two particle sampling devices, one inside the cabin and the other outside. With the standard cellulose filter, the filtration efficiencies of submicron and respirable (>1 p,m) dust were 68 % and 86 %, respectively. However, with the cellulose/nanofiber composite filter, a higher reduction of approximately 92 % has been observed for both the submicron and respirable dusts. Besides, the results showed that submicron salt crystal preferentially collected on nanofibers (compared... 

Cabin air filtration, for cars at least, was introduced with the 1939 Nash, but did not survive the demise of that marque. Not until the mid 1980s did European manufacturers start to fit cabin air filters as standard equipment, soon followed by Ford in the USA and other American manufacturers quickly thereafter. It is almost certainly a case of application following development of suitable media - as synthetic nonwovens became available, so did it become apparent that they could be used for cabin air filtration (refer back to Figure 5.7). 

The third layer in the cabin air filter medium is a coarser material, mainly to provide support to the fine layer. 

Vehicle cabin ventilation filters are designed to supply fresh filtered air into the passenger compartment through the automotive heating and air conditioning, or interior air recirculation systans. These filters can be more than 90% efficient and, where electrically charge fibres made from 100% polypropylene are used as the filter medium, so... 

An important feature of the medium used to provide vehicle cabin air filtration is that it should provide large filtration areas in a relatively small volume. This means that it will almost certainly be pleated. It should also be relatively easily changed (a high proportion of private vehicle filters are never changed, partly because of the owner s ignorance of where the filters are and/or how to change them). 

However, in the 90s, ironically with more evolved technology, ventilation systems in aircraft were built in such a way as to recycle stale air, thus increasing the chances of survival of bacteria and deleterious particles in the aircraft cabin. Even if such a practice were ineluctable, in that recycling is a universal practice which is calculated to conserve fuel, a prudent airline would lake other measures, such as change of air filters through which ventilation is provided. 

Wisthaler et al. (2005) used PTR-MS to examine the products formed when ozone reacted with the materials in a simulated aircraft cabin, including a loaded high-efficiency particulate air (HEPA) filter in the return air system. 

Smaller occupied spaces are also beginning to receive attention. For example, activated carbon filters have been introduced in automobile passenger cabins to remove odorous contaminants from inlet air and increase passenger comfort. These filters are installed only by a few manufacturers at present Mercedes, BMW and Porsche in Germany and in the Mercury Mystique and Ford Contour models in the USA [36]. Particulate filters are normally integrated into automobile climate control systems to remove dust and pollens, and these can now be... 

Chiselling, needling In these processes mainly coarse particles are produced which are difficult to remove through extraction. The work is mainly carried out in cabins for safety reasons. In special cases, e.g. when removing bumt-on sand, the generated dust may be extracted by an extraction arm. The exhaust air is decontaminated in cyclones, wet washing and dry filters... 

Wet scrubbers and fabric filters have been installed and operated successfully for many years. Fettling cabins with high-efficient dust arrestment units can be run stackless, as their output is cleaner than the usual fettling shop air. They also help to improve workplace conditions. 

It is expected that the smaller size of these nanofibres will lead to a higher pressure drop and the interception and inertial impaction efficiencies will increase faster, which can more than compensate for the pressure drop inaease. Nanowebs have been used in many air filtration applications. Airborne contamination in the personnel cabins of mining equipment is of concern to mining workers, and it has been reported that nanofibre filter media can considerably reduce cabin dust concentration as compared to the standard (cellulose) filter media. ... 

Nonwoven filter media also play an important role in today s vehicles. In total, there are more than 50 filters in an average passenger car, contributing to functions ranging from the performance of the engine and oil and fuel consumption through to the quality of the air in the cabin. 

Willey and Waterbury (1989) used a substantially different method to study chemotaxis in the marine cyanobacterium Synechococcus sp. This experiment involved the use of blind-well chemotaxis chambers (Neuroprobe, Inc., Cabin John, MD) that consisted of an upper (800- il) and lower (200- li1) acrylic chamber separated by a polycarbonate filter (3.0 pm). A cell suspension (165 pi) of the cyanobacterium was placed in the lower chamber over which the polycarbonate filter was placed. An air space was left between the cell suspension and the filter to control the starting time of the experiment. The upper chamber was filled with sterile seawater containing the compound to be tested and then inverted, allowing the cell suspension to contact the polycarbonate filter and the seawater/compound solution. The experiments were run for 65 min, after which time the chambers were inverted to stop the experiment. The number of cells crossing the filter into the seawater chamber was determined by direct cell counts using epifluorescence microscopy. The motile strain of Synechococcus sp. tested in this assay elicited positive chemotaxis to compounds such as ammonia, nitrate, urea, glycine, and P-alanine. Control chambers with the same concentration of chemoattractant in both the upper and lower chambers failed to elicit a chemotactic response. While the compounds tested in this study were relatively simple metabolites, one could... 

The need for proper ventilation of vehicle cabins, whether an agricultural tractor, a private car or a passenger airplane, has been recognized only comparatively recently. This means that air intake (or recirculation) filters are not only required, but also must be able to remove airborne dust, pollen and microbes very efficiently. 

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