The plate filterpress is an industrial machine whose purpose is to separate the solid fraction from the liquid fraction in relation to a certain flow of fluid (in jargon called sludge) pumped into the machine itself.
By means of a series of different filtering elements and a certain available useful volume, the filter press s dehydrates the incoming sludge and concentrates the solid fraction into what is commonly called a residual cake (which is then discharged and subsequently disposed of or reused depending on the process in which we are involved).
The plates are designed to create, once aligned, a series of chambers where the sludge is pumped through a feed hole common to all the plates.
Initially, the filterpress is closed by an hydraulic system (one or more pressure cylinders) which are not used to press the sludge but simply align the plates and keep them pressed together, so as to guarantee tightness and counter pressure to that of the feed pump.
The sludge, in fact, is pumped in by the pump, is pushed into each chamber, filling them, and begins to press on the filter cloths according to the pressure induced by the filtration pump.
In this way the solid particles are retained on the cloths, while the liquid phase passes through them and is channelled back into the system in a separate line, ready to be reused.
As the filtration continues, the solid particles accumulate inside the chamber to create a kind of tile, called a cake.
When the system decides that the desired concentration has been reached inside the chamber (usually by controlling the flow of clean water and the filtration pressure), the sludge pump is stopped, the pressure of the sludge and the hydraulic filter closure is discharged, and the filter press opens, spacing the filtration plates and discharging the solids in the form of filtration cakes. The discharge speed depends on the model of filter press, and the auxiliary devices used.
