The working principle of the box filter press consists of filter plates arranged to form filter chambers (with each filter plate having concave sides, two plates combine to form a box-shaped filter chamber).

The filter plates have ridges and raised platforms on their surfaces for supporting the filter cloth. There are holes in the center and corners of the filter plates, which, upon assembly, form a complete passage for the suspension liquid, washing water, and the extraction of the filtrate. Handles on both sides of the filter plates are supported by cross beams and are tightened by a clamping device. The filter cloth between the plates serves as a seal.

Under the pressure of the feeding pump, the material liquid to be filtered is sent into each filter chamber, where it is separated from solids and liquids through the filter medium (selecting appropriate filter cloth based on different industries). The filter cake forms on the filter cloth until it fills the filter chamber. The filtrate passes through the filter cloth and flows along the filter plate grooves to the lower outlet channel, where it is discharged. After filtration, cleaning water can be introduced to wash the filter cake. Sometimes, compressed air is also introduced after washing to remove any remaining cleaning fluid. After the filtration process is complete, the pressure filter is opened to remove the filter cake (stored between adjacent filter plates), the filter cloth is cleaned, and the plate filter is re-tightened to begin the next working cycle.