Hydrocyclone (Mud Cleaner, desander, desilter)Troubleshooting

12 desander polyurethane cone
5 inch polyurethane hydrocyclone
Figure 1. polyurethane hydrocyclone

Hydrocyclone is core part of mud cleaner (desilter, desander). Hydrocyclones are a cost-effective method of removing many of the fine solids missed by the shaker in unweighted muds.

Hydrocyclones separate solids from fluid by using centrifugal force to cause solids to be settled from the fluid. There are no moving parts. Centrifugal force is created by the conversion of centrifugal pump head into a high velocity stream spiraling within the cone. Solids concentrate in proportion to their mass near the wall of the cone and are discharged at the bottom of the cone in the underflow. Clean fluid and fine solids are returned through the top of the cone in the overflow.

Mud cleaner, Desander, Desilter (Hydrocyclones) Troubleshooting

SymptomsProbable Causes
One or more cones are not discharging - others OK.Plugged at feed inlet or outlet - remove cone and clean out lines.
Some cones losing whole mud in a
Backflow from overflow manifold, plugged cone inlet.
High mud loss, conical shape in
some cones - others normal.
Low inlet velocity due to partially plugged inlet or cone body.
Repeated plugging of apexes.Too small underflow opening, bypassed shaker or torn screens.
High mud loss, all cones, weak
stream, conical shape.
Low feed head check obstruction, pump size and rpm, partially closed valve, solids settling in feed line, frozen lines.
Cones at discharge end discharge
poorly with a dryer stream.
Strong vacuum in manifold discharge line, usually occurs with long drop into pits - install antisiphon tube.
Cone discharge is unsteady, varying feed head.Air or gas in feed, too small feed lines, air from
upstream equipment discharge.
Motor protection fuses “blow.”Required input horsepower is higher than rated horsepower of motor - check for tees bypassing mud, additional equipment, manifolding.
Low impeller life.Cavitation in the pump - flow rate is too high - need larger lines. Suction line blockage - check for obstructions.
Mud percent solids continues to increase.Solids removal is insufficient, solids may be too fine to remove, insufficient cones to match drilling rate - add cones.
Cones are discharging a heavy,
slow-moving stream.
Cones are overloaded - use larger apex size, insufficient cones to match drilling rate - add more cones.
High mud losses.Cone opening is too large - reduce size or consider centrifuging underflows.
Aerated mud downstream of hydrocyclone overflow return.Viscous mud, return line ends above fluid level in tank - route hydrocyclone overflow into trough to allow air to break out.
desilter twin-cone
desilter twin-cone


1 comment
  1. Jannette
    June 19, 2018 at 3:50 am

    Thanks for the excellent article

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