An Investigation on the Relationship between Dust Emission and Air Flow as Well as Particle Size with a Novel Containment Two-Chamber Setup

Abstract

In the present study with a novel two-chamber setup (TCS) for dustiness investigations, the relationship between pressure differences as well as air velocities and the resulting dust emissions is investigated. The dust emissions of six particle size fractions of acetaminophen at pressure differences between 0 and 12 Pa are examined. The results show that both simulated and measured air velocities increase with increasing pressure difference. Dust emissions decrease significantly with increasing pressure difference and air velocity. Fine particles cause higher dust emissions than coarse particles. A high goodness of fit is obtained with exponential and quadratic functions to describe the relationship between pressure difference and dust emission, indicating that even moderate increases in pressure may lead to a reduction in the emission. Average air velocities within the TCS simulated with Computational Fluid Dynamics are between 0.09 and 0.37 m/s, whereas those measured experimentally are between 0.09 and 0.41 m/s, both ranges corresponding to the recommended values for effective particle separation in containment systems. These results underline the ability of the novel TCS to control pressure and airflow, which is essential for reliable dust emission measurements and thus provide support for further scientific and industrial applications.

Keywords: HPAPI; containment; dust emissions; dustiness; flow barrier; two-chamber setup.

Figure 1

Simplified illustration of the TCS in a closed state (a) and an open state (b). 1: Orifice for pressure compensation of the emission chamber; 2: Orifices for the double-acting ball valves for atomization and oppositely directed convective flow; 3: Orifices for pressure compensation of the detection chamber during the detection phase; 4: Orifice for the IOM sampler; 5: Orifices for the attachment of thermal sensors of the differential pressure gauge; 6: Orifices for the measurement of the differential pressure with the differential pressure gauge; 7: Connection orifice between the emission and the detection chamber.

Figure 2

Illustration of the TCS and the constructive components for fastening the pneumatic components: (a) TCS in closed state; (b) TCS in open state.

Figure 3

Piping and instrumentation diagram of the individual pneumatic components by the PLC of the TCS.

Figure 4

Detailed illustration of the TCS, its aluminum profiles, and pneumatic components: (a) TCS in closed state; (b) TCS in open state.

Figure 5

Simplified diagram of the three measurement phases of the TCS.

Figure 6

Simplified illustration of the thermal anemometer located within the orifice between the emission and detection chambers featuring five different measurement points.

Figure 7

(a) Overview of the three measurement phases (red: atomization phase, blue: transport phase, green: detection phase); (b) pressure differences during the atomization phase; (c) pressure differences of 0–12 Pa during the transport phase; (d) pressure differences during the detection phase (means ± SD, n = 3).

Figure 8

Air velocities at pressure differences of 1–12 Pa between the emission chamber (left) and the detection chambers (right).

Figure 9

Air velocity versus pressure difference (means ± SD, n = 3).

Figure 10

Dust emissions of ACAM 1–ACAM 6 at pressure differences between 0 and 12 Pa (means ± SD, n = 3).