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What is the permeability of the filter cloth?

July 01,2022

The filter cloth is a filter medium used for solid-liquid separation and gas-solid separation. When it comes to filtration, one of the characteristics of the filter cloth should be considered, that is, permeability. Permeability is an important parameter to characterize the filtration characteristics of the medium. Permeability is a characteristic of biofilm, which refers to the ability of net movement of water caused by concentration difference, such as soil and porous rock, which refers to its ability to allow water to pass through; The permeability and filtration precision of filter cloth are also important indexes to clarify the permeability of filter cloth.


The filter cloth often plays a decisive role in the success or failure of filtration. The air permeability and filtration accuracy of the filter cloth are used as a standard to measure filtration. When selecting the filter cloth, we will give priority to these two factors, especially precision filtration. Because it is necessary to ensure that the filtration is precise enough to filter the filter residue and leave the desired semen.


At present, there are two main ways to express the permeability of filter cloth: the general expression, which is applicable to thin-film media and takes the thickness as a constant; the air flow rate per unit area is used to characterize the permeability of the medium; the other expression is less used. It uses the permeability coefficient to characterize the permeability of the medium, but this expression is more rigorous in theory.


The larger the air permeability of the filter cloth, the larger the aperture, the larger the small particles that can be retained, so the filtering accuracy is poor; On the contrary, the smaller the air permeability and pore diameter, the smaller the small particles that can be retained, the better the filtration accuracy.


  1. Permeability coefficient

The permeability coefficient Kp of the medium is defined by Darcy equation.


  1. Air permeability

Most expressions of permeability neglect the resistance of the medium, so permeability is tested and quantified by flow rate. Scale based on air flow and base.


In addition to the air permeability and filtration accuracy of the filter cloth, it is also necessary to consider the cake removal, wear resistance, anti-stretching, etc. when selecting the filter cloth. If there are working conditions such as high temperature, acid-base, electrolysis, etc., it is also necessary to add some special considerations, such as high temperature resistance, acid-base resistance, anti-conductivity, etc. If you are looking forfilter cloth company, we are your best choice.

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