In operation, slurry is pumped under pressure into the press chambers through the manifold at the stationary head of the filter press. As each chamber fills with slurry, the liquid passes through the cloth medium, across the drain-field, through the drain ports and exits via gravity out of the corner discharge eyes.
The prime function of the filter media is to provide a porous support structure for the filter cake as it develops and builds.
Initially, some solids may pass through the cloth media causing a slight turbidity in the filtrate, but gradually the larger particles within the slurry begin to bridge the openings in the media reducing the effective opening size. This allows smaller particles to bridge these reduced openings initiating the cake filtration process.
Once a layer of solid particles achieves 1 to 2 mm in thickness, this “precoat” layer serves to separate out finer and finer particles as the cake builds in thickness, yielding a filtrate that is very low in turbidity.