During operation, the pulse bag filter will introduce dust containing gas into the ash hopper through the air inlet duct. Coarse dust particles will directly fall into the bottom of the ash hopper, while fine dust particles will enter the middle and lower boxes with the turning of the airflow. The dust will accumulate on the outer surface of the filter bag, and the filtered gas will enter the upper box and be discharged into the clean gas collection pipe exhaust duct through the exhaust fan to the atmosphere. The dust cleaning process involves first cutting off the clean air outlet duct of the room, so that the bag in the room is in a state of no airflow passing through (stopping the air and cleaning the dust in each room). Then, the pulse valve is opened and compressed air is used for pulse blowing to clean the dust. The cut-off valve is closed for a sufficient time for the dust peeled off from the filter bag to settle in the ash hopper after spraying. The pulse bag filter avoids the phenomenon of dust adhering to the adjacent filter bag surface with the airflow after leaving the filter bag surface, allowing the filter bag to clean the dust. The programmable controller is used to fully control the exhaust valve, pulse valve, and ash discharge valve.
The cleaning cycle of the pulse bag filter should be adjusted according to the actual situation on site. Firstly, the amount of dust accumulated on the bag should be adjusted, and then the wind speed at the outlet of the fan should be measured to see if there is a significant decrease or increase. The design of the pulse bag filter will include parameters for the filtered wind speed.
The cycle of a pulse bag filter is related to factors such as the dust concentration of the gas entering the filter, the filtering wind speed, and the pressure of the gas source used for cleaning. When the concentration is high, the filtering wind speed is high, or the blowing pressure is low, the cycle can be chosen to be shorter. Conversely, the cycle can be appropriately extended. If the blowing cleaning gas source pressure is above 400kpa, the pulse cycle can be selected as 10-30min, and the specific operation can be adjusted according to the reading of the pressure gauge.
Cleaning method of pulse bag filter
1. Backblowing dust cleaning method in separate rooms
The pulse bag dust collector using the split chamber back blowing method adopts a split chamber structure, with valves switching chamber by chamber to form a reverse airflow, forcing the filter bag to shrink or swell for dust cleaning. This dust cleaning method also belongs to the low kinetic energy type of dust cleaning, which uses the working pressure of the pulse bag filter as the cleaning power, and is only equipped with reverse airflow power in situations. The pulse bag dust collector using the split room back blowing dust cleaning method requires the use of a thin filter cloth that is soft in texture, easy to deform, and has stable dimensions. As this pulse bag dust collector has internal and external filters, the selection of filter cloth is slightly different. Generally speaking, circular bags are commonly used for internal filtration, without frames, with a bag diameter of 120-300mm and a bag length to bag diameter ratio of 15-40. Satin (or diagonal) woven filter cloth is preferred, with a thickness of 1.0-1.5mm and a unit area mass of 300-400g/m2; Flat bags, diamond bags, and honeycomb bags are commonly used for external filtration, with supporting frames. Thin needle punched felt filter cloth with good breathability is preferred, with a unit area of 350-400g/m2.
2. Pulse jet cleaning method
The pulse jet dust collector with pulse jet cleaning method is powered by compressed air and uses the pulse jet mechanism to instantly release compressed air flow, inducing several times the secondary air to enter the filter bag at high speed, causing the filter bag to rapidly expand. It relies on impact vibration and reverse air to clean the dust and belongs to the high kinetic energy dust cleaning type. Usually, outer filter bags or flat bags with frames are used. The pulse bag filter requires the use of thick and strong tension resistant filter cloth, with priority given to using synthetic needle punched felt or compressed felt filter cloth, with a unit area mass of 500-650g/m2.
3. Vibration blowback combined with dust cleaning method
The pulse bag dust collector with vibration back blowing and combined cleaning method refers to a pulse bag dust collector that has both vibration and reverse airflow cleaning effects. Its vibration loosens the dust cake and the reverse airflow separates the dust. The two methods work together to improve the dust cleaning effect, especially suitable for filtering fine particulate viscous dust. The selection of filter cloth for pulse bag dust collector is generally the same as that of the dust collector with chamber back blowing method.
