This part of GB/T 28957 specifies particle size distribution and chemical content limits involving four grades of test dust made from Arizona desert sand and two test dusts of BF silica series.
This part is applicable to the determination of the performance of filters for road vehicles. It is also applicable to the determination of the performance of filters for general use internal combustion engines, and to the research on wear and tear of bearings, seals and other components.
2 Terms and Definitions
2.1
loose density
ratio of the mass of dust to its filling volume, including the space between the dusts, in the absence of vibration of the diffused dust
3 Test Dust Description
Test dusts according to this part are manufactured from Arizona desert sand. Arizona desert sand is a naturally occurring contaminant consisting primarily of silicon dioxide with smaller amounts of other compounds. It is collected from a select area of Arizona desert, jet-milled and classified to specific particle size. The two kinds of test dust of BF silica series are manufactured from natural mineral materials, which consisting primarily of silicon dioxide with smaller amounts of other compounds, screened and classified to specific particle size.
Note 1: Arizona desert sand has also been referred to as Arizona road dust, Arizona test dust, Arizona silica, AC fine or coarse test dust, and SAE fine or coarse test dust.
Note 2: the BF silica series test dusts specified in this standard include BF1 silica test dust and BF2 silica test dust, among which BF2 silica test dust is 270 mesh quartz sand with assigned value.
Arizona desert sand has a density of approximately 2 650 kg/m3. Table 1 gives the loose density of test dusts made from Arizona sand varies with particle size.
