desilter

A desilter is a solids-control device used in drilling fluid systems to remove fine solids from drilling mud. It is typically a hydrocyclone-based assembly that operates after the desander in the solids-control train. The desilter consists of multiple small-diameter hydrocyclones arranged in a manifold. The drilling mud is pumped into the cyclone tangentially; centrifugal forces separate solids by density. Heavier cuttings and sand-size particles report to the underflow, while the clarified fluid exits via the overflow. The underflow is returned to the mud system or disposed of, depending on solids content. The cut point of a desilter is finer than that of a desander, allowing removal of finer silt and clay particles, typically in the tens of microns range, though exact sizes depend on equipment and operating conditions. Desilters are used to improve mud performance, reduce abrasion and wear on pumps and bits, and maintain drilling efficiency. They are commonly part of a mud-cleaning train that may include shale shakers, desanders, mud cleaners, and centrifuges. In other contexts, hydrocyclone-based desilters are also used in mineral processing and wastewater treatment to separate fine suspended solids from liquids.