Fresh air system, in addition to fresh air, of course, there must be filtration, simple fresh air will only bring outdoor haze and other pollution into the room, just like the previous ventilator, and filtration to ensure the purity of fresh air into the room, as for how the fresh air system is filtered, this needs to be further examined, after all, the naked eye is not visible, when purified to a certain index can not be felt, then here to talk about the common filtration methods and principles on the market.

At present, there are many brands and models of fresh air systems, and various filtration methods are also emerging, but in essence, they are basically passive filtration! What is active and what is passive? In the air purifier, there are photocatalysts and other substances, which can be actively released into the air to kill and eliminate bacteria, dust, etc. in the air, which is active purification. However, similar purification methods often have their own disadvantages and are not used in fresh air systems.

The passive purification and filtration of the fresh air system means that the purification filter/filter element of the fresh air system is fixed, and the air must pass through this filter/filter element to complete its filtration.

At present, the fresh air system is commonly used in the filter mode, and some models are equipped with electrostatic precipitator or ultraviolet sterilization, but it is still mainly filter-based. When the outdoor air passes through the filter, the PM2.5 contained in the air, bacteria and other pollutants will be absorbed by the filter, and the grade of the filter directly determines the purification efficiency.

In the current fresh air system market, the basic ones are coarse filter, medium efficiency filter, and high efficiency filter.

Among them, the coarse filter is used to isolate more than 5μm of particles, wool and other pollutants, it has a great role, and the price is relatively cheap, so it is almost the standard of all fresh air systems.

Medium-efficiency filter, mainly filtering 1-5μm particles, its function is mainly to relieve the purification pressure of high-efficiency filter and extend the service life of high-efficiency filter.

High-efficiency filter is the focus of purification, the level of high-efficiency filter, directly determines the purification efficiency of the fresh air system, generally like this regular machine, high-efficiency filter uses HEPA filter, the filter itself can achieve PM2.5, 99.97% purification efficiency!

Sub-high-efficiency filter, is some fresh air system steal concept installed filter, the actual role of sub-high-efficiency filter, compared with high-efficiency filter effect is much worse, therefore, when purchasing, must pay attention to the must have a high-efficiency filter. The existence of medium and crude efficiency filters can extend the service life of expensive high-efficiency filters, so it is also necessary. Technologies such as electrostatic precipitation and ultraviolet sterilization can bring purification efficiency to a higher standard!

Of course, the purification efficiency mentioned above is only for the filter, and some fresh air systems, even if equipped with HEPA filters, can not achieve the purification efficiency mentioned above, and the fundamental reason is subject to passive purification methods. The passive purification method of the fresh air system requires that all the air must pass through the filter screen to achieve the filtration effect, if the sealing of the fuselage is not good or the design is defective, even if it is only a little, it will have a great impact on the purification effect!

Therefore, when purchasing a fresh air system, workmanship is also a very important point!