Medium-efficiency bag air filter manufacturers

Medium-efficiency filters belong to the F-series of air filters. The F-series medium-efficiency air filters are divided into bag and non-bag types. Bag types include F5, F6, F7, F8, and F9, while non-bag types include FB (panel medium-efficiency filter), FS (partition medium-efficiency filter), and FV (combination medium-efficiency filter).

1. Interception: Airborne dust particles move with the airflow due to inertial motion, random Brownian motion, or the influence of some field force. When particles collide with other objects, the van der Waals forces (forces between molecules and molecular clusters) cause the particles to adhere to the fiber surface. Dust entering the filter media has more opportunities to collide with the media, and upon impact, it becomes trapped. Smaller dust particles collide and agglomerate to form larger particles that settle, resulting in a relatively stable concentration of dust particles in the air. This is why indoor surfaces and walls fade. It is a misconception to view fiber filters as sieves.

2. Inertia and Diffusion: Particulate dust undergoes inertial motion in the airflow. When it encounters randomly arranged fibers, the airflow changes direction, and the particles, due to inertia, deviate from their trajectory and collide with the fibers, becoming adhered. Larger particles are more likely to collide, resulting in better filtration. Small particulate dust undergoes random Brownian motion. The smaller the particle, the more intense the random motion, the more opportunities to collide with obstacles, and the better the filtration effect. Particles smaller than 0.1 micrometers in the air mainly undergo Brownian motion; smaller particles result in better filtration. Particles larger than 0.3 micrometers mainly undergo inertial motion; larger particles have higher efficiency. Particles with little diffusion or inertia are difficult to filter. When measuring the performance of high-efficiency filters, the efficiency value for difficult-to-measure dust particles is often specified.

Medium-efficiency bag air filter manufacturers

3. Electrostatic Effect: Due to various reasons, fibers and particles may become charged, generating an electrostatic effect. Electrostatically charged filter materials can significantly improve filtration performance. Reason: Electrostatics cause dust to change its trajectory and collide with obstacles; electrostatics also make dust adhere more firmly to the medium. Materials that can generate static electricity are also called "electret" materials. When a material is charged with static electricity, its resistance remains unchanged, but the filtration effect is significantly improved. Static electricity does not play a decisive role in the filtration effect; it only plays an auxiliary role.

4. Chemical Filtration Chemical filters primarily selectively adsorb harmful gas molecules. Activated carbon materials contain numerous invisible micropores with a large adsorption area. In a grain of rice-sized activated carbon, the micropore area is several square meters. When free molecules come into contact with activated carbon, they condense into liquid within the micropores and remain there due to capillary action; some even fuse with the material. Adsorption without obvious chemical reaction is called physical adsorption. Some activated carbon undergoes treatment, causing the adsorbed particles to react with the material, generating solid substances or harmless gases; this is called chemical adsorption. The adsorption capacity of activated carbon continuously weakens during use. When it weakens to a certain level, the filter will become unusable. If it is only physical adsorption, heating or steam fumigation can remove harmful gases from the activated carbon, regenerating it.