Cyclonic air filtration equipment

The invention relates to an air filtration bank (100) and an air filtration system (50) for removing grit or impurities from an airstream using a plurality of cyclonic air classifiers (10) arranged in 2×2 arrays in each air filtration bank (100). The system (50) comprises a plurality of interconnected, modular air filtration banks (100) arranged side-by-side and a grit collecting chute (5). In order to improve airflow efficiency and particle separation, each cyclonic air classifier (10) includes a vortex-inducing inlet duct (13), an extraction pipe (16) and a conical diffuser (15). The conical diffusers (15) of upper and lower cyclonic air classifiers are of different lengths such that their respective waste outlets are not coplanar which serves to limit waste outlet flow interference and results in less pressure drop across the air filtration bank, which in turn leads to more efficient particle removal.