Principle of action:
A simple filter is formed by separating the container into upper and lower chambers with a filter medium. The suspension is added to the upper chamber, and under the action of pressure, the suspension enters the lower chamber through the filter medium to form the filter liquid. The solid particles are intercepted on the surface of the filter medium to form the filter residue (or filter cake). During the filtration process, the filter residue layer accumulated on the surface of the filter medium gradually thickens, and the resistance of liquid passing through the filter residue layer increases, and the filtration speed decreases. When the filter chamber is full of filter residue or the filtering speed is too small, stop filtering, remove the filter residue, and regenerate the filter medium to complete a filtering cycle. The liquid must overcome the resistance through the filter residue layer and the filter medium, so there must be a pressure difference on both sides of the filter medium, which is the driving force to achieve filtration. Increasing the pressure difference can accelerate the filtration, but the deformed particles are easy to plug the pore of the filter medium when the pressure difference is large, and the filtration is slowed down.