The negative-pressure downward-inlet reverse-blow bag filter, with its unique design, efficiently purifies dust-laden gases. Its operation mainly consists of three closely interlinked stages: filtration of dust-laden gases, monitoring of filter bag resistance, and reverse-blow dust cleaning.
Filtration of Dust-laden Gases
Under a negative-pressure environment, due to the suction force generated by the fan, dust-laden gases are drawn into the dust collector from the dust hood. The gases enter the bag chamber from the lower part of the dust collector. Inside the bag chamber, cylindrical filter bags are suspended. As the dust-laden gases pass through the filter bags, the bags, by virtue of their physical barrier properties, trap the dust on their surfaces. Only the purified gases can pass through the filter bags. These clean gases flow upward through the interior of the filter bags, enter the upper exhaust duct, and are then discharged into the atmosphere through the chimney under the action of the fan. During this process, a dust layer gradually forms on the surface of the filter bags. This dust layer is not only a product of the filtration process but also, to some extent, aids in filtration, enhancing the interception of fine dust.
Monitoring of Filter Bag Resistance
As the filtration process continues, more and more dust accumulates on the surface of the filter bags, and the resistance for gases to pass through the bags gradually increases. In the dust collector system, pressure sensors are installed to continuously monitor the pressure difference across the filter bags, that is, the resistance of the dust collector. When the pressure difference reaches the pre-set upper limit, it indicates that the filtration performance of the filter bags has been severely affected by dust accumulation. If not cleaned in a timely manner, the dust removal efficiency will be significantly reduced, and the energy consumption of the system will increase. At this point, the reverse-blow dust cleaning program is triggered.
Reverse-blow Dust Cleaning
The reverse-blow dust cleaning process is achieved through the orderly opening and closing of three-way reversing valves. When dust cleaning is required, the three-way reversing valves act to change the gas flow direction, allowing some of the purified gases to enter the filter bags in the reverse direction. This reverse-blow gas flow is opposite to the direction of the gas flow during filtration and has two effects. On the one hand, the static pressure of the reverse-blow gas flow deforms the filter bags. The originally cylindrical filter bags are compressed into a star-shaped or one-line cross-section. On the other hand, the high-speed reverse-blow gas flow directly impacts the dust layer on the surface of the filter bags. When the reverse-blowing ends, the filter bags return to the filtration state. The filter bags vibrate due to the drastic change in shape. Under the combined action of bag deformation, gas flow impact, and vibration, the dust layer adhering to the surface of the filter bags falls off, drops into the ash hopper at the lower part of the dust collector, and is then discharged through the ash discharge device. However, because the forces of the reverse-blow gas flow acting on different parts of the filter bags vary, this dust cleaning method sometimes leads to local dust shedding, resulting in patchy peeling.
The above three stages cycle continuously, ensuring the continuous, stable, and efficient operation of the negative-pressure downward-inlet reverse-blow bag filter and enabling the purification of dust-laden gases.
Established in 1992, XieChang has its own factory buildings covering an area of over 50,000 square meters. We independently research and develop and produce bag dust collector accessories such as electromagnetic pulse valves, pulse controllers, filter bags and cages. These products have served over 40,000 customers in industries like metallurgy, petrochemical, cement, electricity, and waste incineration.
