An Evaluation of Sharp Cut Cyclones for Sampling Diesel Particulate Matter Aerosol in the Presence of Respirable Dust

Abstract

Two prototype cyclones were the subjects of a comparative research campaign with a diesel particulate matter sampler (DPMS) that consists of a respirable cyclone combined with a downstream impactor. The DPMS is currently used in mining environments to separate dust from the diesel particulate matter and to avoid interferences in the analysis of integrated samples and direct-reading monitoring in occupational environments. The sampling characteristics of all three devices were compared using ammonium fluorescein, diesel, and coal dust aerosols. With solid spherical test aerosols at low particle loadings, the aerodynamic size-selection characteristics of all three devices were found to be similar, with 50% penetration efficiencies (d50) close to the design value of 0.8 µm, as required by the US Mine Safety and Health Administration for monitoring occupational exposure to diesel particulate matter in US mining operations. The prototype cyclones were shown to have ‘sharp cut’ size-selection characteristics that equaled or exceeded the sharpness of the DPMS. The penetration of diesel aerosols was optimal for all three samplers, while the results of the tests with coal dust induced the exclusion of one of the prototypes from subsequent testing. The sampling characteristics of the remaining prototype sharp cut cyclone (SCC) and the DPMS were tested with different loading of coal dust. While the characteristics of the SCC remained constant, the deposited respirable coal dust particles altered the size-selection performance of the currently used sampler. This study demonstrates that the SCC performed better overall than the DPMS.

Testing a revised inlet for the personal dust monitor

“…The penetration efficiencies of the original and revised inlets were evaluated with a commonly used method for characterizing size selectors’ performance. [9–12] An aerosol composed of glass microspheres (Cospheric, Santa Barbara, CA) was injected into a calm air chamber, at a constant rate, using a TSI 3400A fluidized bed dust generator (TSI Inc., Shoreview, MN). The material in the generator was an equal-mass combination of two microsphere products with different distributions: one set of spheres had a median diameter of 3 μ m and 90% of the spheres were smaller than 8 μm; the second set had a median diameter of 10 μm and 90% of the spheres were smaller than 18 μm.…”

Laboratory comparison of new high flow rate respirable size-selective sampler

“…Solid soda-lime glass microspheres (2.5 g/m 3 density, Cospheric, Santa Barbara, CA) were generated in a calm air chamber [17] using a fluidized bed dust generator (Model 3400, TSI Inc.) and a Kr-85 aerosol neutralizer (Model 3054A, TSI Inc.). An APS (Model 3321, TSI Inc.) was used to measure the particle size distribution and its calibration was verified prior to the experiment with polystyrene latex (PSL) spheres (Thermo Fisher Scientific, Pittsburgh, PA).…”

Performance evaluation of a 3D-printed sharp-cut cyclone

“…9 Due to its unique characteristics, the SCC family of cyclones is currently employed in many applications, (e.g., regulatory sampling of particles emitted by diesel engines), as it fullls the requirements of many regulatory authorities. 19 Cyclones are in general inexpensive compared to other components used in aerosol measurements. However, for applications where the cut-off diameter is required to be accurate, their price can become signicant, ranging from hundreds to a couple of thousands USD due to the required manufacturing precision, adding to the overall cost of the measuring system.…”