Mechanism of interpleat channel blockage in pleated filters during dust loading

Pleated filters are widely employed in industrial and domestic applications owing to their high dust-holding capacity and compact structure. However, the formation of dust dendrites can lead to blockage of the pleat channels, thereby causing a rapid increase in pressure drop. This study systematically investigates the filtration performance of pleated filters with different pleat ratios and the factors influencing channel blockage through experimental research and theoretical analysis. The results demonstrate that when the dust deposition is substantial, the formation of a large number of dust dendrites can result in interpleat channel blockage and a sudden increase in filter core pressure drop. The critical areal dust loading for channel blockage is identified, and it is revealed that the formation of dust dendrites is influenced by the pleat ratio of the filter, dust particle size, and filtration face velocity. Specifically, higher pleat ratios, smaller dust particle sizes, and filtration face velocities are found to be more conducive to the formation of dust dendrites. Further mechanistic analysis illustrates that dust dendrite formation arises from the dynamic interplay between the combined interparticle forces (van der Waals forces, electrostatic forces, and liquid bridge bonding forces) and the aerodynamic force imposed by the airflow. A strong aerodynamic force causes dendrite fragmentation, while a weak aerodynamic force enables sustained dendrite growth. These results provide valuable technical support for the design and optimization of pleated filter elements in practical engineering.