Optimized pleat geometry at specific pleat height in pleated filters for air purification

The performance of an air purifier is determined by its clean air delivery rate (CADR), expressed as the product of the air flowrate and filter collection efficiency. A high CADR in a commercial air purifier is achieved using a pleated air filter with high filtration performance at a given air flowrate. However, obtaining this high filtration performance depends on the knowledge of the manufacturer, including the optimal pleating design, which remains uncertain to date. In this study, test pleated filters were prepared by folding a flat electrostatically-charged E12 filter medium to obtain different pleating geometries. The proper pleat geometry of the pleated filter, which has a minimum pressure drop at a fixed air flowrate, was dependent on the pleat length (P_L ) and pleating ratio (α = pleat height/pleat width), wherein as the P_L increases, the α range required to achieve a minimum pressure drop similarly increases. Based on the filter quality factor (q_F ), the optimal pleat geometry of a pleated filter was between α values of 6-8, irrespective of the P_L . Although both P_L and α have certain influences on the q_F , α has a greater influence on the pleated filter with no dead zone.