Detailed explanation of the final resistance of the air filter As the filter accumulates, the resistance increases. When the resistance increases to a certain value, the filter is scrapped and needs to be replaced. The resistance of the new filter is called “initial resistance†and the resistance when the filter is scrapped is called “final resistanceâ€. Several factors that affect the ultimate resistance of the air filter: 1. Filter mechanical strength Larger filters, smaller proportions of frames and fixtures. When the resistance is too large, the filter may be loose or damaged. From this aspect, the final resistance is determined, and its value is generally too large, so it is generally not considered. 2. High efficiency filter replacement cost (price + labor) 3. Filter running resistance energy consumption 4. System air volume allowable range of variation 5. Filter efficiency changes Low-efficiency filters (below G4) often use a coarse fiber filter with a diameter > 20 μm; a fiber gap of about 200-400 μm; and a filtered wind speed of about 0.5-2 m/s. When the resistance is too large, the ash on the filter will be taken away by the airflow. At this time, although the resistance is no longer increased, the filtration efficiency drops sharply. Therefore, for such filters, consider replacing them before their efficiency drops. According to the previous factors, for domestic users: Filter efficiency specification recommended final resistance (Pa) G3 (coarse effect) 100-150 G4 150-200 F5-F6 (medium effect) 150-250 F7-F8 (high school efficiency) 250-400 F9-H11 (sub-efficient) 350-450 High efficiency air filter and ultra efficient 400-600 to sum up: Air filters are often the most important component that causes changes in the airflow in a ventilation system. For air-conditioning designers, the fan and air conditioner should be selected according to the determined filter initial resistance and the allowable air volume range. It also provides the final resistance value when the user changes the filter. For existing ventilation and air conditioning systems, if there is no final resistance value and equipment details provided by the air conditioner supplier, the final resistance should be determined according to the allowable range of the system air volume and other conditions. Sideboard Cabinet,Sideboard Buffet Cabinet,Sideboard Storage Cabinet,Sideboard Display Cabinet DUOBUY TECHNOLOGY SHANDONG CO., LTD. , https://www.doubuytech.com