First of all, what is a HEPA filter. English full name is called High - Efficiency Particulate Air, namely the High Efficiency Particulate Air filter, HEPA for short. Accord with standard of HEPA filter USES a wide range, from medical equipment, automotive, aircraft and household applications. Filter criteria set by the U.S. department of energy, the size in 0.3 microns particles, the filtering effect of DOP by more than 99.97%. Usually use efficient filter interception efficiency can reach 99.99%.
HEPA filter with complete classification, retain the coarse filter, medium efficiency filter, and high efficiency filter and highly efficient filter. According to the use scope of different can also be divided into medical and related classification. And on the manufacturing material, HEPA manufacturing also include glass fiber and plastic fiber and other materials.
Through the above brief introduction, I believe everyone can feel the HEPA filter filtration efficiency is very important, if the higher the HEPA efficiency air purifier is better?
In general air purifiers clean air volume (CADR value) of two factors: HEPA filter efficiency, air purifier, air volume. Air purifier air flow with HEPA efficiency is also related, general HEPA efficiency is higher, the resistance is, the greater the purifier of the actual ventilation rate will decrease. Number of air volume decreases, and the purification of the unit time will also drop, CADR value reduced. The machine all the parts of collocation is the most important thing.
The next line lixin again to introduce the HEPA filter to purify the air pollution.
1, the screen effect
When the medium composition (fiber, mesh, corrugated metal, etc.) between the gap size is less than the diameter of particles, the filter designed to capture these particles. This principle is widely used in most of the filter design, all depends on the diameter of the particle size and the distance between medium and medium density.
2, inertial effect
With rapid changes in air direction and the principle of inertia will be a lot of (particles) separated from the air. At a certain speed of the particles tend to keep this rate, and keep the same direction to move on. Process if the particle concentration is high, the general application of this principle. And, in many cases, the pre-filter mode and terminal filter adopts the principle of more efficient.
3, interception effect
In order to achieve the interception, a particle must be from a fiber radius range to enter. Particles so contact with fiber and attached to it. Intercept principle compared with embedded principle, the difference is intercepted small particles, and the inertia can't enough to make particles continue to straight lines. So let air flow until contact with fiber.
4, the diffusion effect
Dust of less than 1 mu m does not vary with air movement, but rather because of air molecules impact "Brownian motion". If the impact on the filter fiber were captured. So, the smaller the particle, Brownian motion, the more intense, the better the filtering effect.
After watching the above introduction, lixin believe that everyone should be on HEPA filter and filter principle of it has probably understanding, now air purifier is generally more than a layer of filter screen, just like we circulate air purifier has five heavy rope lixin filter to purify the air pollution.
