Basic theories of ash removal-01 Flow resistance characteristics of filter cloth

Basic theories of ash removal-01 Flow resistance characteristics of filter cloth

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Author : filterworkshop.com
Update time : 2020-02-03 14:53:37
Basic theories of ash removal-01
As for the
bag filter, the theories of dust removal is as important as the theories of filtration, because only the two links of filtration and dust removal are carried out continuously and alternately can form a complete dust removal process.
 
1 - Flow resistance characteristics of filter cloth
 
The flow resistance of filter cloth is one of the important indexes to measure the bag body filter. The fluid resistance of the filter cloth not only determines the power consumption of the
dust removal equipment, but also affects the dust removal system and working efficiency of the equipment.
The resistance of the filter cloth in the working state includes two parts, namely, the pressure loss of the filter cloth itself and the pressure loss of the particle layer.
When the gas passes through the filter cloth, half of the layers are laminar. At this time, the filter cloth has resistance to the gas medium.
The resistance of several filter materials is shown in Figure 1.


 At the same flow rate, due to the different weaving structure and resistance coefficient of the filter cloth, the resistance of the needle felt is about 1 / 4 ~ 1 / 2 lower than that of fiberglass cloth and industrial polyester flannelette. In the process of using the filter cloth, there must be a dust layer, resulting in pressure loss, that is, the pressure loss of the particle layer.
The pressure loss of particle layer varies with void fraction. Under the same filtering wind speed, the dust load on the surface of the same filter cloth is different, and its pressure loss is also different (see Figure 2 below):


Under the same filtering wind speed, with the increase of the dust load on the surface of the filter cloth, the fluid resistance of the air flow through the filter cloth also increases, which is closely related to the surface dust load; when the surface dust load is greater than 800g / m2, the fluid resistance of the air flow through the filter cloth increases sharply with the increase of the filtering wind speed, which has a positive significance for determining the anti blowing system of the dust removal equipment.
 
Figure 3 below is the relation curve between dust load and resistance. It shows that under the same dust load, the pressure loss value of different filter materials is also different, because the porosity of the dust layer formed on the filter cloth is affected by the physical properties and load of the dust, the structure of the filter cloth, the filtering speed and other factors.