Jet plus bag filter includes filtration and dust-cleaning process during operation.
New filter-bag erected can be used as sieve that can hinder dust contained in gas during filtration, which particle size is larger than sieve mesh. For dust with particle size (1~10μm) less than sieve mesh, which would adhere on filter cloth due to inertial impaction. Dust build-up is increased with filtration process due to dust lapping on surface of filter cloth and sieve mesh, dust layer with small aperture forms on air-intake surface of filter cloth (primary dust-layer), which can be used as filter medium as well to improve greatly filtration efficiency and trap nearly all dust particle contained in gas. When dust-layer becomes thicker (secondary dust-layer), de-dusting efficiency is higher, but filter resistance is increased as well, and gas flow passes through difficultly. At the same time, porosity of dust-layer is reduced, speed of gas flow passing through micro-pore is increased, which can extrude and blow-out minimal dust particle adhering on micro-pore, and result de-dusting efficiency reduced. Hence filter-bag should be dust-cleaned with pulse.
When dust-cleaned process with pulse is undergoing, compressed air should be used to pulse-inject filter-bag every fixed time with pulse valve as per specified program. When pulse controller starts pulse valve, compressed air in air tank injects into filter-bag from hole of ejection pipe within 0.1～0.2 S. Ejection hole and Venturi are arranged centrally. Since line-type of Venturi generates injection, it can induce air flow nearly 5～7 times of compressed air to enter into filter-bag simultaneously, which results filter-bag impacted, expanded and vibrated abruptly, and together with effort of reversed airflow, dust trapped on surface of filter-bag can be cleaned, then which falls down into dust hopper.