Effect of induced airflow on the surface static pressure of pleated fabric filter cartridges during pulse jet cleaning

Abstract

Filter cartridges with higher pleat ratios and larger filter surfaces are often cleaned incompletely because of the great variation in the static pressure distribution along the surface of filter cartridges during the pulse jet cleaning process. This study examined the static pressure distribution of filter cartridges and attempted to reduce the incidence of incomplete cleaning, particularly at the top of a filter cartridge, where less static pressure could cause systematic unstable operations. Pressure loss and static pressure behavior were observed across pleated filter cartridges in a dust collector during the pulse jet cleaning process. The instantaneous pressure drops of pleated filters were measured, and filter aging over time was recorded. The pressure drops of pleated filters with induced airflows are less significant than those without induced airflows. The static pressure and the continuous pressure time on the filter cartridges surfaces were obtained using a pressure transducer. The induced airflow was used to alter the static pressure distribution along the filter cartridge surface. The air axial velocity gradually decreased from the supersonic induced nozzle and through the air diffuser. Otherwise, radial velocity increased before encountering the filter cartridge surface, and the dynamic pressure was quickly converted into static pressure at the top of the filter cartridge before being transported to the middle of the filter cartridge and then immediately to the bottom. Sometimes, partial airflow moved into the filter cartridges and rebounded from the bottom of the filter cartridges, thereby forming partial static pressure at the bottom. Thus, the static pressure decreased from the top of the filter cartridge to the bottom. The experimental results show that the static pressure at the top area of the filter cartridges is 23–17kPa and the static pressure at the bottom area of the filter cartridges is 4.7–1.6kPa via the operational time with the 0.6MPa tank pressure in our experiment. The measured results are in good agreement with our photos. This variation resolved the cleaning difficulty at the top of the filter cartridge and maintained the entire systematic sustainable operation.