High efficiency axial wet cyclone air sampler

Abstract

Early detection of highly contagious viral diseases is particularly important for controlling and minimizing the spread of these viruses. Moreover, the sampling of airborne viruses is a crucial step towards an effective epidemic diagnosis. However, most air samplers require long sampling times, and real-time virus detection is consequently not possible. Therefore, in this study, an axial-type wet cyclone capable of obtaining highly concentrated samples in an outdoor environment in real time was developed. In the newly designed axial wet cyclone, the airborne particles are firstly collected by centrifugal force in cyclone vanes rotating several times and then captured by inertial force before the air enters the outlet. The collection efficiency at 500 L min–1 was tested with polystyrene latex (PSL), and it was observed that the air sampler efficiency for 1.1 µm and 2 µm PSL was approximately 50% and 90%, respectively. For the large-sized PSL (> 3 µm), the observed collection efficiency was almost 100%. The Stokes number was used to design geometrically similar cyclones with air sampling rates of 100 L min–1 and 300 L min–1. The results of the scaled sampler show a somewhat lower collection efficiency than for the 500 L min–1 device but with lower liquid consumption and a lower pressure drop. For 100 L min–1 and 300 L min–1 samplers, the cutoff point for collection efficiency was approximately 1.5 µm and 3 µm PSL, respectively.