The Change of Filtration Performance of Bag Filters over Time

Bag filters play a crucial role in industrial dust control. However, as the operating time increases, the filtration performance and strength of the filter media inevitably decline. Usually, after 4 - 6 months of operation, the filtration performance is only one-sixth of that of the new filter cloth, and the strength also drops to 60%.

This performance change is affected by various factors. If the dust particle size is small and the concentration is high, it is easy for the dust to adhere to the surface and pores of the filter media, accelerating the clogging. If the filtration speed is too fast, the filter media has no time to clean the dust, which will also lead to clogging. The temperature, humidity, and corrosiveness of the treated gas cannot be ignored. High temperature can change the material properties of the filter media, high humidity can cause the dust to agglomerate, and corrosive gases can corrode the filter media, all of which will reduce the performance and service life of the filter media.

In this process, the dust-cleaning link is of vital importance. Timely and effective dust cleaning can prevent excessive dust accumulation on the surface of the filter media, maintain the air permeability and filtration performance of the filter media, extend the service life of the filter media, and ensure the continuous and stable operation of the dust collector. As the core component of the dust - cleaning system, the pulse valve is of self - evident importance. The pulse valve quickly opens and closes to inject high - pressure gas into the filter bags. The powerful impact force generated instantaneously can peel off the dust attached to the surface of the filter bags, achieving efficient dust cleaning. If the pulse valve malfunctions, such as being unable to open or close normally, or having insufficient blowing pressure, the dust - cleaning effect will be greatly reduced, which will in turn cause the pores of the filter media to clog rapidly, the pressure drop to rise sharply, and seriously affect the working efficiency of the dust collector.

Understanding the changes in the performance and strength of the filter media is of great significance for formulating maintenance and replacement plans, as well as for equipment operation monitoring and maintenance. The aging of the filter media is more intuitive, such as a change in color and a brittle texture.

In actual operation, fine dust, high concentration, and fast filtration speed are likely to clog the pores of the filter cloth. The degree of clogging is related to the weaving method and surface treatment of the filter cloth. It usually takes about 50 days for the pressure drop after dust cleaning to reach a stable value. If the pressure drop increases sharply, it indicates that the performance of the filter cloth has seriously declined and needs to be replaced or repaired in a timely manner. Otherwise, it will affect the dust - removal effect and the production process.