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The purpose of this study is to compare the dust loading behavior of ten filter media. The filters are used in engine air filtration, self-cleaning industrial air cleaners, building heating ventilation and cooling (HVAC), automotive cabin air filtration, air respirators, and general purpose air cleaning. Several types of filter media are tested. The filters include cellulose, synthetic (felt), glass, dual-layered glass/cellulose, mixed synthetic/glass, gradient packing glass, and electrically charged fibers. The initial pressure drops and fractional collection efficiencies as a function of particle size are reported. The filters were evaluated with two test dusts to investigate the size-dependent dust loading behavior. The two test dusts are SAE fine and submicron alumina powder (median diameter 0.25 μm). The results are analyzed and compared. It was found that the cellulose filters exhibited surface loading behavior and have the fastest growth of pressure drops.

The dust holding capacity of air cleaning filter depends on the size distribution of the particles. Traditional test dusts like Arizona road dust consist of a single mode of coarse particles. The purpose of this study is to evaluate the dust holding capacities of air filters with a bi-modal test dust that simulates the dust in atmospheric environments. The fine mode of the test dust consists of submicron Alumina particles that represent the fine particles in atmosphere. The coarse mode consists of traditional AC fine dust. The fine and coarse dusts are mixed in different mass ratios to simulate different atmospheric conditions. The ratios are 100% fine, 50%/50%, 25%/75%, 10%/90%, and 100% coarse. An engine air filter and a HVAC filter were studied with the bi-modal test dusts. The filter pressure drops were measured as a function of the dust loading. The results show that the flow resistance rises significantly faster as the ratio of fine to coarse fraction increases.