The working principle of the box filter press consists of filter plates arranged to form filter chambers (with concave sides, two plates combine to form a box-shaped filter chamber).
The filter plates have surface pockmarks and raised platforms to support the filter cloth. There are through-holes in the center and corners of the filter plates, which, upon assembly, form a complete passage for the suspension liquid, washing water, and extraction of the filtrate. Handles on both sides of the filter plates are supported by beams and are clamped to secure the filter plates. 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. Solid and liquid are separated through the filter medium (suitable filter cloth selected according to different industries). Sludge forms on the filter cloth until it fills the filter chamber to create a filter cake. The filtrate passes through the filter cloth and flows along the filter plate grooves to the lower outlet channel, where it is discharged collectively. After filtering, the filter cake can be washed with cleaning water. After washing, compressed air may be introduced to remove any remaining cleaning liquid. At the end of the filtering process, 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 start the next work cycle.