- Pest Control[6]
- Other Home Appliances[2]
- Air Purifier Parts[2]
- UV Lamp[5]
- Ultraviolet Lamps[5]
- Auto Sensors[1]
- Air Filter[3]
- Air Cleaning Equipment Parts[4]
- Chemical Auxiliary Agent[3]
- Water Treatment[1]
- Dust Collector[1]
- Other Industrial Filtration Equipment[2]
- Car Freshener[1]
- Other Home Appliance Parts[1]
- Air Purifiers[6]
- Other Electronic Components[1]
- Dining Chairs[6]
- Contact Person : Ms. Jiang Jessica
- Company Name : Ningbo City Haichuang Electronic Co., Ltd.
- Tel : 00866-574-56667111
- Fax : 0086-574-56679177
- Address : Zhejiang,Ningbo,No.156, Lane298, Wangchun Road,Haishu district,Ningbo China
- Country/Region : China
- Zip : 315016
HEPA filters
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HEPA filters can remove at least 99.97% of particles 0.3 (µm) in diameter. Particles of this size are the most difficult to filter and are thus considered the most penetrating particle size (MPPS). Particles that are larger or smaller are filtered with even higher efficiency.
HEPA filters are composed of a mat of randomly arranged fibres. Key metrics affecting function are fibre density and diameter, and filter thickness. The air space between HEPA filter fibres is much greater than 0.3 μm. The common assumption that a HEPA filter acts like a where particles smaller than the largest opening can pass through is incorrect. Just as for , particles so large that they are as wide as the largest opening or distance between fibres cannot pass in between them at all. But HEPA filters are designed to target much smaller pollutants and particles are mainly trapped (they stick to a fibre) by one of the following three mechanisms:
Interception, where particles following a line of flow in the air stream come within one radius of a fibre and adhere to it. Impaction, where larger particles are unable to avoid fibres by following the curving contours of the air stream and are forced to embed in one of them directly; this effect increases with diminishing fibre separation and higher air flow velocity. Diffusion, an enhancing mechanism is a result of the collision with gas molecules by the smallest particles, especially those below 0.1 µm in diameter, which are thereby impeded and delayed in their path through the filter; this behaviour is similar to and raises the probability that a particle will be stopped by either of the two mechanisms above; it becomes dominant at lower air flow velocities.Diffusion predominates below the 0.1 μm diameter particle size. Impaction and interception predominate above 0.4 μm. In between, near the 0.3 μm MPPS, diffusion and interception predominate.
The initial filter air flow resistance and final filter air flow resistance are typically measured as drop across the filters
HEPA filters