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How do I determine the dust holding capacity of an air filter?
How do I determine the dust holding capacity of an air filter?When choosing an air filter, the dust capacity is one of the most important deciding factors. The so-called dust capacity is not the weight of atmospheric dust that the filter can hold at the end of its life, but the weight of test dust that the equipment can hold under specific test conditions. And what do we mean by "specific" here?1. A standard test wind tunnel and associated measurement equipment. 2. Standard "road dust" which is significantly larger than the actual atmospheric dust particles. 3. Test methods and calculations agreed upon between the client and the testers, or as specified in the standard. 4. Termination of the test conditions as determined by the client and the filter manufacturer. Here we will focus on the test termination conditions, for which there are different standards in various places, we will mainly look at the test termination conditions stipulated in the mainstream European and American standards: 1. When the resistance of the equipment reaches twice the initial resistance or higher, the filtration efficiency is less than 85% of the high-efficiency value, and the resistance of most filters is only rising but not falling. The higher the final resistance of the test, the greater the value of the dust capacity obtained, so the conditions for termination of the test should be clearly defined before the test, otherwise, the test data of the dust capacity is not very meaningful. 2. The European Eurovernt 4/9 standard specifies a termination test resistance of 450 Pa, which is much higher than twice the initial resistance. 3. The Chinese standard only stipulates a dust test for coarse filters, the purpose of which is to obtain a weighting efficiency rather than a dust capacity. 4. In European and American standards, the test dust is commonly known as ASHRAE dust, the main component of which is "AC fine dust", which is a specific floating dust (ArizonaRoadDust) in the desert of Arizona, USA. |
