Loading filters with monodisperse aerosols

Brown, Richard C. D.; Wake, D.

doi:10.1016/s0021-8502(98)00042-1

Cited by 22 publications

(13 citation statements)

References 7 publications

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“…The phenomenon of lter clogging and/or particle dendrite growth has been observed in a number of studies (Brown and Wake 1999;Payatakes and Tien 1976;Kono et al 1998;Sioutas et al 1999;Thomas et al 1999;Walsh and Stenhouse 1997;Barrett and Rousseau 1998;Ferer and Smith 1998;Smith et al 1998). The factors in uencing the speci c dust cake resistance coef cient, K 2 , include the ltration velocity (Cheng and Tsai 1998;Dennis and Dirgo 1981;Dennis and Durham 1979;Spaite and Walsh 1963), the particle shape, and the size distribution of the challenge particles (Cheng and Tsai 1998;Japuntich et al 1994).…”

Section: Introductionmentioning

confidence: 93%

Experimental Study on the Loading Characteristics of Needlefelt Filters with Micrometer-Sized Monodisperse Aerosols

Chen

Huang

et al. 2001

Aerosol Science and Technology

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In this work, three types of needlefelt lters, made of Polyester (PE), Ryton Sulfar (RS), and Polyaramid (PA), were tested to investigate the aerosol loading characteristics of fabric lters when challenged with micrometer-sized monodisperse potassium sodium tartrate (PST) particles. A brous lter with packing density of 9%, thickness of 0.38 mm, and ber diameter of 5.1 µ m was included for comparison. A vibrating ori ce monodisperse aerosol generator was used to produce three different sizes (5, 10, and 20 µ m) of PST particles for aerosol loading experiment. An ultrasonic atomizing nozzle and a TSI constant output nebulizer were used to generate polydisperse PST particles for the aerosol penetration test. The aerosol penetration of submicrometer-sized particles through the lters was measured by using a Scanning Mobility Particle Sizer. An Aerodynamic Particle Sizer was used to measure the penetration fraction of aerosol particles larger than 0.8 µ m. The pressure drop across the lter was monitored by using pressure transducers, which were calibrated against an inclined manometer. Air ows of 5, 10 , 20, and 30 cm/s were used to study the ow dependency. The aerosol penetration results showed that the particles larger than 3 µ m did not penetrate the clean fabric lters tested in the present study. The loading curves (plots of pressure drop against sampling time) displayed three regions: an initial region of fast increase, a transition region, and a nal linear region after the dust formation point. After the formation point of the dust cake, both fabric and brous lters shared the same slope (of the loading curves). The slope of different regions of the loading curves was determined by many factors, such as size of challenge aerosol, face velocity, surface treatment, and the compressibility of the dust cake forming on the lter. The method of nal surface treatment was found to be critical to the performance of the fabric lters. In order to avoid the unnecessary rise in air resistance, the melting clumps formed during nal surface treatment should be as thin and narrow as possible, just enough to support the lter bag cleaning. From the standpoint of lter quality and energy consumption, the low ltration velocity has to be adopted whenever possible, because high ltration velocity not only led to lower lter quality (in particular for submicrometer-sized particles) but also created dust cake of lower porosity, which caused an extra rise in pressure drop across the dust cake.

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Section: Introductionmentioning

confidence: 93%

Experimental Study on the Loading Characteristics of Needlefelt Filters with Micrometer-Sized Monodisperse Aerosols

Chen

Huang

et al. 2001

Aerosol Science and Technology

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“…The power of attraction between an aerosol particle and a fibre depends inter alia on the value of their electric charges. Thus, the neutralization of electric charges, which is often observed for RPE, causes a rapid decrease in filtration efficiency (Brown and Wake, 1999;Brown et al, 1988;Chen et al, 1993;Huang, 2013;Li and Jo, 2010;Yang et al, 2007).…”

Section: Introductionmentioning

confidence: 97%

Influence of Low-Temperature Plasma Treatment on The Liquid Filtration Efficiency of Melt-Blown PP Nonwovens in The Conditions of Simulated Use of Respiratory Protective Equipment

Majchrzycka

Brochocka

Urbaniak–Domagała

2017

Chemical and Process Engineering

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Filtering nonwovens produced with melt-blown technology are one of the most basic materials used in the construction of respiratory protective equipment (RPE) against harmful aerosols, including bio-and nanoaerosols. The improvement of their filtering properties can be achieved by the development of quasi-permanent electric charge on the fibres. Usually corona discharge method is utilized for this purpose. In the presented study, it was assumed that the low-temperature plasma treatment could be applied as an alternative method for the manufacturing of conventional electret nonwovens for the RPE construction.Low temperature plasma treatment of polypropylene nonwovens was carried out with various process gases (argon, nitrogen, oxygen or air) in a wide range of process parameters (gas flow velocity, time of treatment and power supplied to the reactor electrodes). After the modification, nonwovens were evaluated in terms of filtration efficiency of paraffin oil mist. The stability of the modification results was tested after 12 months of storage and after conditioning at elevated temperature and relative humidity conditions. Moreover, scanning electron microscopy and ATR-IR spectroscopy were used to assess changes in surface topography and chemical composition of the fibres. The modification of melt-blown nonwovens with nitrogen, oxygen and air plasma did not result in a satisfactory improvement of the filtration efficiency. In case of argon plasma treatment, up to 82% increase of filtration efficiency of paraffin oil mist was observed in relation to untreated samples. This effect was stable after 12 months of storage in normal conditions and after thermal conditioning in (70 ± 3)°C for 24 h. The use of low-temperature plasma treatment was proven to be a promising improvement direction of filtering properties of nonwovens used for the protection of respiratory tract against harmful aerosols.

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“…Pressure drop evolution of fibrous filter under continuous aerosol loading has been studied by Bergman et al [1], Vendel et al [2], Letourneau et al [3], Novick et al [4] and Thomas et al [5] focusing on HEPA filters. Pressure drop evolution models not specific to HEPA filters have been developed by Brown and Wake [6], Sakano et al [7] and Miguel [8].…”

Section: Introductionmentioning

confidence: 99%

Investigation on pressure drop evolution of fibrous filter operating in aerodynamic slip regime under continuous loading of sub-micron aerosols

Leung

Hung

2008

Separation and Purification Technology

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Loading filters with monodisperse aerosols

Cited by 22 publications

References 7 publications

Experimental Study on the Loading Characteristics of Needlefelt Filters with Micrometer-Sized Monodisperse Aerosols

Experimental Study on the Loading Characteristics of Needlefelt Filters with Micrometer-Sized Monodisperse Aerosols

Influence of Low-Temperature Plasma Treatment on The Liquid Filtration Efficiency of Melt-Blown PP Nonwovens in The Conditions of Simulated Use of Respiratory Protective Equipment

Investigation on pressure drop evolution of fibrous filter operating in aerodynamic slip regime under continuous loading of sub-micron aerosols

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