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Various factors affecting filter efficiency?

Time: 2023-02-14

Various factors affecting filter efficiency: air resistance, wind speed, filter area.

Filtration efficiency is differentiated according to the size of permeable ions and the amount of filtered fine dust. In most cases, the level of filtration efficiency directly depends on the following factors: air resistance, wind speed, filtration area and so on have a great relationship.

First, air resistance

The moving air flow meets the filter material, so that the air flow around, while generating small resistance, countless filter fibers are the whole filter device in a certain wind speed to produce a certain resistance and become the air resistance of the filter device. When the filter device reaches a certain resistance value (final resistance value), it is necessary to replace the filter device, so as to ensure the filtering effect. In most cases, the final resistance value is set at 2 -- 4 times the ancestral value. The dirtier the filter device is, the larger the resistance value is, and the smaller the air volume will be under the corresponding same wind speed.

Do not think that after cleaning, filtration resistance is no longer increased that the filtration device has been restored filtration function, in fact, the filtration efficiency is zero at this time. Therefore, filter equipment is consumable.

Ii. Wind Speed

In most cases, the lower the wind speed, the higher the filtration efficiency. Because at low wind speed, small dust diffusion effect is obvious. The longer the air flow stays in the filter, the more chance the dust will hit the obstacle. A filtration effect is obvious. For the filter material with high efficiency, if the wind speed is reduced by half, the dust passing through the filter material will be reduced and the efficiency will be increased by 9. When the wind speed is doubled, the dust probability of the filter material will be doubled, and the efficiency will be reduced by an order of magnitude (by a 9). When the wind speed is low, the probability of large particles colliding with fibers decreases when they move in inertia. However, this effect is not obvious in practical applications, because the wind speed decreases, the rebound force of fibers on dust also decreases, and dust is easier to adhere, and the filtering effect is significantly improved. Therefore, in practical application, try to set reasonable filtering parameters of low wind speed. It is of great benefit to filtration efficiency and effect.

Three, filtration area

The resistance of filter device increases with the increase of gas flow rate and velocity. The resistance of dust captured or adhered to the air flow increases, so that the air resistance of the air filter device increases. On the other hand, the filter efficiency is slightly improved because the captured dust filter medium adheres to one body and forms a new filter barrier. But the overall filtering effect depends on the size of the filter device area. Therefore, the life of the filter device is related to the filter area.

Four, filter material

The selection and application of filter material is the core technology of bag dust collection equipment, which plays a decisive role in the performance of high efficiency air filter dust collector. Because of the environment of dust collection points, the nature, temperature and technical requirements of dust treatment are different, different filtration materials should be selected according to different conditions, and corresponding technical protection measures should be taken. The requirements for filter materials include the following technical performance: filter bag material is suitable for different temperatures, good stripping, easy cleaning, good air permeability, low resistance, high filtration efficiency, high strength, can withstand high strength cleaning, long service life, suitable price.

Five, air leakage

Air leakage directly affects the dust collection effect and life of the dust collector, and the air leakage rate is required to be less than 3%. Bag dust collector is generally negative pressure operation, such as air leakage is easy to form a small circuit short circuit. Dust collection system processing air volume is not enough, forming positive pressure dust. Air leakage will also reduce the system temperature, easy to produce tide paste bag, increase the dust collection resistance, reduce the filtering effect of high efficiency filter equipment.

Six, filter the wind speed

The air speed filtered by high efficiency filter is a very important parameter to determine the performance of the dust collector, and also an important parameter to measure the advanced nature of the bag dust collector. The filtration wind speed is closely related to the dust concentration, dust particle size, application situation, viscosity, gas temperature, moisture content and cleaning method of dusty gas. When the dust particle size is fine, the temperature and humidity are high, the concentration is large, and the viscosity is large, the filter wind speed should be lower, and the high value can be selected on the contrary. Excessive filtration wind speed will increase the load of filter bag, increase filtration resistance, resulting in short service life and low efficiency of filter bag

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