The Cleaning Process of Bag Filters

During the operation of bag filters, as the filtration process continues, a dust layer gradually forms on the surface of the filter media. The accumulation of dust causes the operating resistance of the bag filter to increase exponentially, which is in line with the relevant theories in fluid mechanics regarding the resistance of porous media and the amount of dust accumulation. At the same time, according to the inverse relationship between flow rate and resistance, the processing air volume continuously decreases.

When the operating resistance reaches the pre-set threshold value, the ash-cleaning process needs to be initiated. Ash-cleaning methods include mechanical vibration ash-cleaning, reverse-blowing ash-cleaning, and pulse-jet ash-cleaning. Among them, pulse-jet ash-cleaning has become the most widely used ash-cleaning method due to its high efficiency and convenience. In the pulse-jet ash-cleaning system, electromagnetic pulse valves and pulse controllers play crucial roles. The pulse controller, as the core control unit of the system, precisely controls the opening and closing times of the electromagnetic pulse valves according to the pre-set program. The electromagnetic pulse valve is the execution component of the ash-cleaning air flow. When the pulse controller sends a signal, the electromagnetic pulse valve opens instantaneously, injecting compressed air into the filter bag at a very high speed, creating a strong reverse air flow inside the filter bag, causing the filter bag to expand and contract rapidly, and thus prompting most of the dust to peel off from the surface of the filter media.

However, even after ash-cleaning, some fine dust still remains inside the fiber layer or adheres firmly to the fiber surface. This part of the remaining dust, together with the fiber layer, forms a stable filtration medium, namely the primary dust layer. The dust that can be effectively peeled off from the surface of the fiber layer during normal ash-cleaning is defined as the secondary dust layer. The stable formation of the primary dust layer usually requires thousands of filtration-ash-cleaning cycles, which may last for several months. During this process, factors such as the particle size distribution of the dust, the material and structure of the filter media, and the ash - cleaning intensity interact with each other.

For bag filters with a compartment-type structure, the ash-cleaning process follows the principle of sequential cleaning of each compartment. This ash-cleaning method can effectively maintain the stability of the filter efficiency, operating resistance, and system air volume of the bag filter, ensuring the efficient and stable operation of the entire dust-removal system.

In the XIECHANG Intelligent Dust-Removal Solution, the XieChang Cloud System, with the help of advanced sensor technology and data analysis algorithms, monitors key parameters such as air tank pressure and flow rate in real-time. Through in-depth analysis of the real-time changes in air tank pressure, it accurately judges whether the bag filter system meets the ash-cleaning conditions and whether the energy consumption meets the design standards. When the air tank pressure exceeds the normal range, it may cause the electromagnetic pulse valve to open with excessive force, not only causing mechanical damage to the valve body and filter bags but also significantly increasing energy consumption. Conversely, if the air tank pressure is too low, the electromagnetic pulse valve may not fully open, resulting in insufficient ash-cleaning air flow intensity and a significant reduction in ash-cleaning efficiency. In addition, by using the Dust - Removal Management Cloud Platform, the working status of the air tank is comprehensively monitored and analyzed, which can timely judge whether the ash-cleaning process of the bag filter meets the process requirements and achieve intelligent management and optimization of the dust- removal system.