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Effect of wind speed on filter

日期:2020-09-28 16:09
浏览次数:171
摘要:In most cases, the lower the wind speed, the better the filter works. The diffusion effect of dust with small particle size (Brownian motion) is obvious. As the wind speed is low, the airflow will stay in the filtration material for a longer time, and the dust will have more chances to hit obstacles, so the filtration efficiency is high. Experience has shown that for filters, a halving of wind speed reduces the transmittance of dust by nearly an order of magnitude (an increase in the effici
In most cases, the lower the wind speed, the better the filter works.

The diffusion effect of dust with small particle size (Brownian motion) is obvious. As the wind speed is low, the airflow will stay in the filtration material for a longer time, and the dust will have more chances to hit obstacles, so the filtration efficiency is high. Experience has shown that for filters, a halving of wind speed reduces the transmittance of dust by nearly an order of magnitude (an increase in the efficiency value by a 9), and a doubling of wind speed increases the transmittance by an order of magnitude (a decrease in efficiency by a 9).

Similar to the diffusion effect, when the filter material has static electricity (electret material), the longer the dust stays in the filter material, the more likely it will be absorbed by the material. When the wind speed is changed, the filtration efficiency of the material with static electricity will be obviously changed. If you know there is static electricity on the material, you should design your air conditioning system to minimize the amount of air passing through each filter.

According to the traditional theory, if the wind speed decreases, the probability of collision between dust and fiber will be reduced and the filtration efficiency will be reduced. In practice, however, this effect is not obvious because the wind speed is lower, the fiber is less resilient to dust, and dust is more likely to stick.

High wind speed leads to high resistance. If the service life of the filter is based on the end resistance, high wind speed, the service life of the filter is short. It is difficult for the average user to observe the effect of wind speed on filtration efficiency, but it is much easier to observe the effect of wind speed on resistance.

For the filter, the velocity of airflow through the filter material is generally 0.01 ~ 0.04m/s. In this range, the resistance of the filter is positively proportional to the filtration air volume. For example, for a 484×484×220mm filter, the initial resistance is 250Pa at rated air volume 1000m3/h. If the actual air volume in use is 500m3/h, the initial resistance can be reduced to 125Pa.

For the general ventilation air conditioning box filter, air flow in the speed of filtering material within the range of 0.13 ~ 1.0 m/s, resistance and airflow is no longer a linear relationship, but a higher arc, air volume increased by 30%, the resistance could be increased by 50%, if the filter resistance is a very important parameter for you, you have to ask filter supplier for resistance curve.