A filter press is a tool used in separation processes, specifically in solid/liquid separation using the principle of pressure drive, provided by a slurry pump. The filter press is used in fixed-volume and batch operations, which means that the operation must be stopped to discharge the filter cake before the next batch can be started. The major components of a filter press are the skeleton and the filter pack. The skeleton holds the filter pack together while pressure is being developed inside the filtration chamber. The chamber however can only hold a specific volume of solids.
Generally, the slurry needed to be dewatered is injected into the centre of the press and each chamber filled. The filling time should be as quick as possible in order to avoid cake formation in the first chamber before the last chamber is filled. While the chambers are being filled up, the pressure inside the system will increase due to the formation of thick sludge. Then, the liquid is filtered out through the filter cloths by adding streams of compressed air or water. The use of pressurized water require more time to pass into the chamber compared to pressurized air, however this method is much more cost efficient.