How to measure the resistance of air filter

When the air filter filters dust, it will cause airflow resistance. According to the current industry usage habits, air filters mainly have two types of resistance: initial resistance and final resistance. The air filter accumulates dust and increases resistance. When the resistance increases to a certain value, the air filter will lose its due function and be scrapped.

The resistance of a new air filter is called“initial resistance”; the resistance value corresponding to the scrapped air filter is called “final resistance”. In design, a representative resistance value is usually needed to calculate the design air volume of the system. This resistance value is called “design resistance”. The usual method is to take the average of the initial resistance and the final resistance.

How to determine the final resistance of Lingjie air filter?

The selection of the final resistance of the air filter is directly related to the service life of the air filter, the range of air volume changes, and the energy consumption of the system. Generally, the selection of the final resistance is a matter for the air conditioning designer. An experienced engineer can change the original designed final resistance according to the site conditions.

Each filter section should be equipped with a resistance monitoring device. The final resistance is determined by the instrument, not just by the operator’s feeling. The cheapest resistance monitoring device is the U-tube differential pressure gauge. Inclined tube pressure gauges and curved tube pressure gauges are more beautiful. The grade and price of differential pressure gauges are relatively high. In addition, there are differential pressure transmitters that convert resistance into electrical signals. In addition to the resistance monitoring device that can be read, an end resistance alarm device should also be added. The trouble-free method is to draw a red bar on the differential pressure gauge; the safe method is to use a differential pressure switch.

Some designers forget to tell the user the final resistance value they selected. Sometimes, users will replace the air filter with another model or another supplier, at which time the field engineer must determine the final resistance value himself. In most cases, the final resistance is 2 to 4 times the initial resistance. The dirtier the air filter, the faster the resistance increases. Excessive final resistance does not mean that the service life of the air filter will be significantly extended, but it will significantly reduce the air volume of the air conditioning system. Therefore, there is no need to set the final resistance value too high.

Low-efficiency air filters often use coarse fiber filter media with a diameter≥10mm. Due to the large gaps between fibers, excessive resistance may blow away the dust accumulated on the air filter. At this time, the resistance no longer increases, but the filtration efficiency drops to zero. Therefore, the final resistance value of air filters below G4 must be strictly limited.

Okay, abouthow to calculate the resistance of the air filter, the author will introduce it to you here. If there are otherhigh-efficiency filters If you have any questions about glue, please contact the author.