Desander, Desilter, Mud Cleaner Core Part – Hydrocylone

Hydrocylone working principle from Eric Tian.

Hydrocylone separators (desander, desilter and mud cleaner) are at work on more drilling rigs around the world. Removing cuttings from drilling mud those hard abrasive particles too small to be rejected by a shale shaker or settling tank. Together Desanders and Desilters remove over 95% of any solids down to 10 microns and size. Smaller than official solids such as collides clay and other small solids are retained in the mud system to ensure suitable wall building characteristics in the borehole. Typical separators are as tough as the equipment they help protect. Mud valves, slurry pumps, manifolds swivels and drill pipe they’re precision engineered to effectively maintain and improve drilling hydraulics by reducing mud weight. They’re efficient and economical helping speed drilling rates reducing the need for water dilution and replenishment extending the life of drill pits.

The heart of the Desander, desilter and mud cleaner are the cyclonic cone (Polyurethane hydrocyclone), ranging from 4-inch to desilter’s up to 12-inch desanders. Drilling fluid under pressure is directed into the cone through the tangential inlet. Rotary movement is created when the fluid strikes the curved inner wall of the cone. This sets up a centrifugal force which separates the fluid into conical layers. The heavier particles are forced to the cone wall and move downward by gravity. As the cone tapers the solids gain speed and separation efficiency increases. These solids are then discharged at the bottom of the cone through this underflow outlet or apex. Meanwhile the lighter fluid now mostly free of solids floats to a vortex or vacuum formed at the center of the cone and is drawn upward through an overflow outlet. Fluids are then returned to the mud system to be reused and the cycle starts again. A hydrocylone is a remarkably simple thing. There are no moving parts and in this 4-inch style desilter only six basic parts make up the completely assemble cone. Maintenance and repair are limited almost entirely to occasional replacement of the protective cone liners.

You’ll notice here near the bottom of the cone. These tattletale warning holes liner wear is more concentrated at these points. Fluid seepage allows you to visually check for liner wear without taking the cone apart. With the few exceptions which will point out, the same basic component parts are used in all Desander and desilter cones. This style each cone is the one you’ll find most often in the desilting operation. It’s longer length increases fluid retention time thereby increasing separation efficiency.