From the evolution of the international high-efficiency filter testing standards, it can be seen that the testing methods of high-efficiency air filters mainly include mass method, colorimetric method, sodium flame method, oil mist method, and particle counting method.
1. Quality method
The dust feeding amount and the filtering and trapping amount are measured by weighing method, and then the mass efficiency is called, which is suitable for coarse pre-filter.
Use sampling filter paper to sample before and after the filter, measure the transmittance of the filter paper before and after the filter with a photoelectric colorimeter (photoelectric densitometer), convert it into the mass of dust particles, and then calculate the mass efficiency. Suitable for medium efficiency filters, electrostatic filters, etc.
3. Sodium flame method
The earlier method originated from the British industrial test and was implemented in the 1970s and 1990s. The dust source was a monodisperse NaCl salt spray, the main instrument was a photometer, and the NaCl solid dust particle distribution was a polydisperse phase (0.007 ~ 1.7 μm). , its combustion in a hydrogen flame can excite a flame with a wavelength of 5 890 A, and then the concentration of sodium chloride particles is measured by a pyroelectric flame photometer, and then the efficiency is obtained according to the concentration before and after the filter, which is suitable for medium and high-efficiency filters.
4. Particle Counter Counting Method
Use atmospheric dust and artificial dust, artificial dust has a DOP (dioctyl phthalate) particle size distribution of about 0.3μm monodisperse phase (heating); it can also be polydisperse phase (pressurization method), the corresponding dust measurement The method is called DOP method (commonly used high-efficiency filter efficiency detection method). The size of the signal determines the number of dust. The method is widely used in high-efficiency filter leak detection, detection and detection of clean rooms.
▲The HVAC air filter replacement cycle, the primary filter is replaced every six months, so the life of the high-efficiency filter can generally be about 2 years, but in order to protect the use of the latter-level high-level filter and ensure the safe operation of the clean room, under normal circumstances Replace once every 2-3 months.
▲Replace the medium-efficiency and sub-high-efficiency filters every 12 months (or use the high-efficiency filter as the protection filter in the final section of the wind cabinet mentioned above), which can ensure the service life of the high-efficiency filter for more than 3 years, and because of the resistance of the new filter after replacement Small, the air conditioner load is greatly reduced, and the cost of filter replacement is far less than the electricity bill required for the operation of the air conditioner.
Frequent replacement of the pre-filter actually enables the air-conditioning system to operate efficiently under a low resistance load, saving a lot of power consumption and achieving the effect of energy saving and consumption reduction.
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