Consists of filter plate is arranged filter chamber (filter plate on both sides of the sunken, every two pieces of filter plate combined into a box shape filter chamber). Principle is as follows: the surface of the filter plate is pitting and convex platform, to support the filter cloth. Filter plate at the center of the hole and edge horn, form a complete channel after assembly, to pass into the suspension, washing water and lead to filtrate. Filter plate with a handle on both sides of the bracket on the beam, pressure filter plate by compaction. Filter plate filter cloth between the sealing effect.

In transporting pump pressure, will need to filter the material liquid into the filter chamber, through the filter medium (according to different industries to choose the appropriate filter cloth), solid and liquid separation. On the filter cloth filter cake formation, until full of filter chamber to form a filter cake. Filtrate through filter cloth and filter plate groove along flow into the pore channels of produced liquid, concentration of discharge. After filtering, can pass into the washing water washing filter residue. After washing, and sometimes into the compressed air, remove the rest of the washing liquid. Filter after the open pressure filter removable filter cake (filter cake store is between adjacent two filter plate), cleaning cloth, keep plate filter to the next work cycle.
Fixed on the plate and frame filter cloth, this is a major form of filter press in the early, the main advantage of the box pressure filter is the replacement of filter cloth is convenient, defect is low efficiency, filtering effect is bad, the filter plate easy bad; Box pressure filter in the filter chamber is made up of two adjacent sag filter plate, filter cloth fixed on each filter plate, box pressure filter's main advantage is higher efficiency, effect is better, filter plate is relatively durable () in the same conditions, but are high degree of automation, clean the filter cloth have automatic device, change the number of filter cloth is generally not frequently.