The working principle of industrial air filter cartridge is mainly based on the three core links of filtration, cleaning and control, and the following is its detailed description:
1. ** Filtration principle **
- ** Interception action ** : When the gas containing dust particles passes through the air filter cartridge, the filter material in the filter cartridge (such as fibers, porous media, etc.) will intercept the particles in the air stream. Due to its inertial action, the larger particles directly collide with the surface of the filter material and are intercepted. The smaller particles will be driven by the air flow, with the flow of air gradually close to the filter material fiber, due to the hook effect of the fiber and the mutual attraction and condensation between the particles, and finally caught by the filter material, so as to achieve gas-solid separation [^2^].
- ** Screening effect ** : the filter material of the filter cartridge has a certain pore structure, when the gas passes through the filter material, the particles smaller than the pore size of the filter material can pass through the filter material, and the particles larger than the pore size are blocked on the surface of the filter material, which plays the role of screening and further removes the particles in the air [^2^].
- ** Electrostatic adsorption ** : Some of the filter material of the air filter cartridge is specially treated to make it have static electricity. When the gas containing dust passes through the filter cartridge, the dust particles will be attracted by the static electricity of the filter material and be adsorbed on the filter material, thereby improving the filtration efficiency [^2^].
2. ** Cleaning principle **
- ** Pulse jet cleaning ** : This is one of the common cleaning methods. When the dust on the surface of the filter cartridge accumulates to a certain extent, causing the resistance of the filter cartridge to reach the set value, the control system will trigger the pulse valve to open. The compressed air stored in the air bag is released instantaneously and sprayed into the filter barrel through the small hole on the spray pipe to form a high-speed and high-pressure jet stream. This airflow causes the filter cylinder to expand and deform instantaneously, producing vibration and reverse airflow, shaking off the dust attached to the surface of the filter material and falling into the ash hopper to achieve ash cleaning [^2^][^4^].
- ** Mechanical vibration cleaning ** : The filter cartridge is vibrated by an external mechanical device to loosen the dust attached to the surface of the filter cartridge and fall off. This method is relatively simple, but for some dust with large viscosity or small particle size, the cleaning effect may not be as ideal as the pulse spray cleaning [^2^].
- ** Reverse air cleaning ** : Use the reverse air generated by the fan to blow from the inside of the filter cylinder to the outside, so that the dust on the surface of the filter cylinder is blown off. This cleaning method is suitable for the case that the filter cartridge is long or the cleaning requirement is high [^2^].
3. ** Control principle **
- ** Pressure difference control ** : During the working process of the air filter cartridge, the pressure difference inside and outside the filter cartridge is monitored in real time through the pressure sensor installed on the inlet and outlet pipes of the filter cartridge. When the pressure difference reaches the maximum value, it indicates that the dust accumulation on the surface of the filter cartridge is excessive, and the cleaning procedure needs to be started. When the pressure difference drops to a certain value, the cleaning is stopped to ensure that the filter cartridge runs in the best working state [^2^].
- ** Timing control ** : According to the preset time interval, regardless of whether the pressure difference of the filter cartridge reaches the set value, the control system will trigger the cleaning procedure regularly. This method is suitable for situations where the working condition is relatively stable and the dust production is more regular, which can effectively prevent the filter cartridge from clogging due to long-term unclear ash, but may cause certain energy waste [^2^].
- ** Manual control ** : In some special cases, the operator can manually start or stop the cleaning procedure according to the actual production situation and the use of the filter cartridge, in order to better control the work efficiency and service life of the filter cartridge [^2^].
To sum up, industrial air filter cartridges remove particles in the air through efficient filtration principles, use a variety of cleaning methods to keep the filter cartridge clean, and ensure stable and efficient operation of the filter cartridge through precise control principles. Together, these principles constitute the indispensable position of the air filter cartridge in industrial production, providing strong support for environmental protection and the improvement of production efficiency.