What are the three stages of filter?
The filtration process can be divided into three stages:
(1) Deep filtration stage: particles mainly enter the filter material and are intercepted and adsorbed by the internal pores and fiber lan. A few particles are intercepted by lan on the inflow surface because the particle size is larger than the surface pores of the filter material. At this stage, the filtration efficiency is mainly affected by the pore size of the filter material itself, and the pressure difference increases slowly.
(2) Filter cake formation stage: with the progress of filtration, the particulate matter in the inflow area of the filter material gradually increases, and gradually forms a layer of filter cake on the inflow surface of the filter material, which reduces the porosity between the surface fibers and accelerates the growth rate of differential pressure.
(3) Filter cake filtration stage: particulate matter continues to accumulate on the inflow surface of the filter material. At this time, the main filtered particulate matter is mainly filtered by the surface filter cake. The pore of the filter cake gradually decreases, and the filter cake structure on the inflow surface of the filter material is more compact due to the increase of the pressure difference, which leads to a sharp rise in the pressure difference.