Rotary drum filters operate under a high vacuum, rotating a drum into a vat of slurry, dewatering and drying as the drum rotates out of solution and over to the cake discharge side. The drum filter cloth is caulked onto the drum and stays in the same place. De-watered and dried filter cake is discharged on the back side using gravity, air blow back, blade or counter-revolving roll.

Rotary drum filter cloths are woven fabrics, ranging from lightweight multifilament cloths to heavy monofilament cloths weighing up to 1500g/m2. Depending on the type of filter, the discharge system, the product and the process, a very wide range of textiles have been used in these filters with life varying from a few weeks to multiple years.