Filter Press

Filter Press

  • Process of eliminating solids from sludge by pressing out the liquid, which result in dry filter cake
  • Feeding pump injects slurry into filter press
  • Operating at high pressure, generally from 5 to 15 bars
  • Pressing time is commonly less than 4 hours, depending on:
    • Cake thickness
    • Concentration of slurry
  • Typically a 90% reduction in sludge volume can be achieved with fully automated operation.


A filter press is a highly efficient, compact, dewatering device for separating solids from liquid slurries in the form of compressed cake. Its major components are a structured framework, filter chambers (formed by recess portion of recessed plate system, or frames in plate and frame system), and filter cloth.

Filter press technology is very basic in nature, but its application is as important to the various processes it serves, as is a simple wheel to the motive machines. Filter Press are separation devices used for solid or liquid separation that work on feed pressure or squeeze pressure to reduce liquid content in process or waste slurries or to reduce solid content in a product.

A filter press consists of a series of horizontally arranged vertical filter plates, each covered with paper, felt medium or synthetic woven material. A mechanical structure called skeleton is used to support the filter plates and a closure mechanism provides the required force on the sealing faces of the plates to counteract the applied force of filtration (squeezing).


The hydraulic cylinder controlling the follower plate presses the plates together creating a sealed unit. Each face of each plate is covered with a filter medium to form a series of perforated chambers into which process material is introduced under pressure.

The liquid passes through the filter cloths on each chamber and is discharged through the filtrate discharge system. The filter medium retains suspended solid particulate. Solids content and remaining water build a cake on the surface of the filter cloth. The slurry is continuously fed under pressure to all chambers. This process continues until cake is compressed to maximum solids concentration. The pump is then shut off; hydraulic pressure is released, and follower plate is retracted. Plates are then separated and cake discharges by gravity into cake disposal container.