The plate filter press is the best-performing mechanical dewatering and filtration process achieving dryness levels of 30 to 80%. It is used for dewatering sludge from industrial and urban effluents as well as for filtration in chemical, pharmaceutical, food processing, ceramics, mining and quarrying processes.
Composition of a filter press
A filter press consists of a succession of plates covered by filter cloths, which are tightened by means of one or two hydraulic
cylinders between a fixed beam and a mobile beam. Leak-tightness at the mating surfaces is ensured by tightening to a pressure of 200 to 300 bar. Faure Equipements offers filter presses equipped with plates from 250 x 250 mm to 2000 x 2000 mm for volumes ranging from 2 to 20,000 litres.
The product to be filtered is introduced using a pump until the required pressure (usually 7 to 15 bar) has been reached. Under this pressure, the liquid passes through the cloth, which retains the solid particles. This filtrate is collected either from each plate or at the end of the filter. The accumulation of material between the plates causes a pressure drop, which is compensated for by the supply pump. This supply pump must regulate its flow according to the pressure in the filter press. Some products require preconditioning, which consists of adding reagents before filtration in order to make filtration possible. This preparation forms an integral part of our knowledge as well as of the services we provide with our turnkey dewatering units and any tests that may be necessary.
A filter press can be equipped with diaphragm plates. Under the action of air or water pressure, this diaphragm compacts the cakes after the filtration phase. In this case, the filtration pressure is usually 8 bar, while the squeezing ensures that the cakes are pressurised to 15 bar. The advantage of plates of this type is that they increase dewatering performance levels, thereby improving productivity and facilitating cake removal. They also allow any cake washing and blowing that may be necessary to be done under optimum conditions.
At the end of the cycle, the cakes formed inside the filter press chambers are removed by gradually separating all the plates. This discharge operation may be manual, mechanised or automated on the latest generation of filter presses equipped with the full auto robot.