How to use different filters together
A filter at the end of the entire filtering system determines the cleanliness of the entire filtering system. In particular, the high efficiency filter and super high efficiency filter are equipped with medium efficiency filter and primary efficiency filter in front of them, so that their filters at all levels can form a step by step protection function, and each of them can protect their more efficient filters in the downwind direction, playing a role in extending their service life.
According to the requirements of the service environment on the cleanliness of the air supply, a protective filter shall be added in front of the end filter equipment for pre filtration. If the prefilter of this level also needs protection, then add a filter at the windward end for prefiltering protection. If one or more prefilters are installed, the efficiency difference between two adjacent levels of filtering equipment cannot be too large. For example, do not setprimary efficiency air filtersto protect HEPA filters or evenultra HEPA filters. If the difference is too large, the previous stage cannot protect the next stage
How should different adjacent filters be used together? What is the appropriate gap?
When classified according to the European standard “G-F-H-U” efficiency specification, a filter is generally set every 2~4 grades. For example: G4 → F8 → H14. The terminal H14 high efficiency filter determines the cleanliness level of the air supply, F8 protects H14, G4 protects F8, and so on
Of course, the specific situation also depends. It shall also be comprehensively evaluated according to industry, site environment, cost performance and other factors. The HEPA filter at the end of the clean room shall be protected by a filter with an efficiency specification no less than F 8; F9~H11 filter can be selected beforeultra high efficiency (ULPA) filter. The air conditioning system itself shall be protected by a filter with an efficiency specification not lower than F5. In areas without wind sand and low pollution, pre filter may not be set in front of F7 filter; In urban air conditioning systems, the common primary filters are G3-F6.