A filter press is only as good as the filter cloth it uses. The cloth is the component that actually performs the separation, retaining solids to form the cake while allowing water to pass through. Cloth selection has a direct bearing on cake dryness, filtration rate, cloth life, and the ease with which cake releases from the cloth at the end of the press cycle. Getting the specification right makes a measurable difference to the overall efficiency and cost of the dewatering operation.

Filter cloths are manufactured from a range of synthetic fabrics, each with different filtration characteristics, strength properties, and chemical resistance. The choice of material and weave pattern depends on the nature of the sludge being dewatered, the chemical environment within the press, and the operating pressure applied during the filtration cycle.

Cake release is an important and sometimes overlooked factor. Poor cake release leaves residue on the cloth surface, reduces effective filtration area, and increases the number of press cycles needed to process a given volume of sludge. A cloth selected with good release characteristics for the specific sludge type reduces this problem and keeps the press operating efficiently over time.

Cloths are subject to mechanical stress from repeated pressing and cloth movement, as well as chemical attack from the sludge and any conditioning chemicals used. Quality cloths maintain their structural and filtration properties through many hundreds of press cycles, but all cloths eventually need to be replaced. Having the right replacement cloth available and changing it before performance deteriorates significantly is an important part of filter press maintenance.

Replacement cloths are available for a wide range of filter press makes and models, and the correct specification can be determined based on the press configuration and the sludge being treated.