bag filter

bag filter

Bag filter is a dry dust removal device. Suitable for collecting small, dry, and non fiber dust. The filter bag is made of textile filter cloth or non-woven felt. Dust containing gases are filtered through fiber fabrics. When dusty gas enters the bag filter, due to the effect of gravity, larger particles and a larger proportion of dust will settle and fall into the ash hopper. When gas containing fine dust passes through the filter material, the dust will be blocked to purify the gas.

The working principle of bag filter:

The bag filter has a good dust removal effect, and its dust removal mechanism cannot be separated from efficiency. The dusty gas enters the ash hopper through the inlet pipe and guide plate under the dust collector. Due to the collision of the deflector and the decrease in gas velocity, coarse dust particles fall into the ash hopper, while the remaining small dust particles enter the filter bag chamber with the gas. Due to inertia, diffusion, barriers, hooks, static electricity, and dust clogging in the filter bag, the purified gas escapes the bag and is discharged through the exhaust pipe. The accumulated dust on the filter bag is removed by gas backwashing method, and the dust is discharged to the ash hopper and then discharged to the ash conveying device through a double-layer ash discharge valve. The dust on the filter bag can also be removed by spraying a pulse airflow to achieve the purpose of cleaning, and the dust below is discharged by the ash discharge device. Bag filters also rely on filter materials. The performance and service life of bag filters are directly related to the performance and quality of filter materials. Filter material is the main material for manufacturing filter bags, and its performance and quality are the progress of bag filter technology, which affects its application scope and service life.

The filtering and dust removal device includes a bag filter and a granular layer filter. The former usually uses filter bags made of fiber or inorganic fiber fabrics as filter layers, while the latter is mainly composed of particles of different sizes, such as quartz sand, river sand, ceramic particles, and slag. As the powder repeatedly adheres to the outer surface of the filter bag, the powder layer thickens and the resistance value of the bag filter increases; The pulse valve diaphragm sends a command, the pulse valve opens, and the compressed air inside the high-pressure safety airbag opens. Mechanical dust removal work will stop if there is no dust or if it is small.

The gas purification mode of the low-pressure pulse bag filter is external filtration mode. Dust gas enters the filtration chambers of each unit through the guide pipe. Due to the reasonable vertical distance between the bottom of the filter bag and the upper opening of the air inlet, the air distribution in the entire filtration chamber is uniform. After natural settling separation, the particulate dust in the dusty gas directly falls into the ash hopper, while the remaining dust enters the middle box filtration zone with the airflow under the guidance of the diversion system. Adsorbed on the outer surface of the filter bag. The filtered clean gas is discharged through the filter bag, the box, and the exhaust pipe.

The filter bag adopts compressed air blowing for ash removal, and the ash removal mechanism consists of an air bag, a nozzle, an electromagnetic pulse control valve, etc. The top of each row of filter bag outlets in the filtration room is equipped with a blowing pipe, and the bottom is equipped with a blowing port. Each blowing pipe is equipped with a pulse valve, which is connected to a compressed air bag. During ash cleaning, the solenoid valve opens the pulse valve, the compressed air opens the electromagnetic pulse spray through the ash spraying control device (pressure difference or timing, manual control) according to the set procedure, the compressed air enters the filter bag through each pulse valve, forming an air wave, which causes the filter bag to expand sharply from the mouth to the bottom and produce shock vibration, resulting in ash removal effect, shaking off the dust on the filter bag.

bag filter