The liquid solid mixture is pumped into the filter press, which is made up of a number of recessed filter plates forming chambers. The plates are supported in a fabricated steel frame and is held closed by a force exerted from a hydraulic ram mounted in the frame work at the end of the machine.

Each filter plate is covered by a filter cloth that retains the solid particles, but allowing the liquid to pass through and exit through the ports in the filter plate.

As the cake forms the pressure within the filter press the pressure rises as the filtrate has to pass through the already partially formed cake to exit the chamber. It becomes increasingly more difficult to continue pumping as the press is unable to accept more solids. At this point the feed pump is stroking infrequently and the filtrate flow from the filter press has considerably reduced or completely stopped.

At this point or at a pre determined filtration time or pressure being achieved the cycle is terminated and the fully formed filter cake is discharged.