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Working Principle of Cleanroom H14 HEPA Filter
Working Principle of Cleanroom H14 HEPA Filter1. Asymmetric fiber filter media structureThe core technology of high-efficiency automatic gradient density fiber filter is to use asymmetric fiber bundle material as filter media, with loose fiber bundles at one end and fiber bundles fixed in the solid body of larger specific gravity at the other end. During filtration, the solid nucleus with larger specific gravity plays a role in the compression of fiber bundles, and at the same time, due to the smaller size of the nucleus, it does not have much effect on the uniformity of the distribution of the void rate of the filtered cross-section, which improves the filtering capacity of the filter bed. The filter bed can fiber over. The filter bed has the advantages of high porosity, small specific surface area, high filtration speed, large dirt-holding capacity, and high filtration precision of fiber filtration. When the suspended matter in water flows through the surface of fiber filter media, under the effect of van der Waals gravitational force and electrostatic force, the adhesion force between the suspended solid and the fiber bundles is much larger than that with quartz sand, which is conducive to the improvement of the filtration speed and filtration precision of high-efficiency filters. When backwashing, due to the specific gravity difference between the core and the fiber filaments, the comet tail fiber spreads out and swings with the backwashing water flow, which generates a strong flinging force; the mutual collision between the filter media also intensifies the mechanical force of the fiber in the water, and the irregular shape of the filter media makes the filter media rotate under the action of the backwashing water flow and airflow, which strengthens the mechanical shear force of the filter media during backwashing. The combined effect of the above forces makes the solid particles adhering to the surface of the fiber easy to fall off, thus improving the cleaning degree of the filter media so that the asymmetric fiber filter media has the backwashing function of the granular filter media at the same time. 2. Continuous gradient density filter bed structure with sparse top and dense bottom. Asymmetric fiber bundle filter media composed of the filter bed in the compaction of the water flow, the water flow through the filter layer resistance, from top to bottom, the head loss is gradually reduced, the water flow rate is getting faster and faster, the degree of compaction of the filter media is getting higher and higher, the porosity is getting smaller and smaller, so that along the direction of the water flow, the automatic formation of a continuous gradient density of the filter layer distribution, the formation of an inverted pyramid of the structure. This structure is very conducive to the effective separation of suspended solids in the water, i.e., the particles desorbed from the filter bed are easily captured and retained in the lower narrow-channel filter bed, which realizes the unity of high filtration speed and high-precision filtration, improves the dirt-holding capacity of the filter, and prolongs the filtration cycle. |
