Hydrocyclone Wear and Selection
Hydrocyclones look simple — no moving parts, no motors, no controls — but they are highly sensitive to wear, apex geometry and feed pressure. This guide walks through how they wear, how to spot underperformance early, and how to size and operate a cyclone bank properly.
1. How a hydrocyclone works
Slurry enters a conical body tangentially under pressure. The resulting vortex throws solids to the wall, where they spiral down and exit through the apex as underflow. Cleaned fluid reverses direction and exits axially through the vortex finder as overflow.
Cut point depends on cone diameter, feed pressure, apex geometry and the vortex finder — not on any external adjustment during operation.
2. Feed pressure sets the cut point
Design feed pressure is typically 30–40 psi. Below that, the vortex weakens and cut point degrades sharply. Above that, wear accelerates without meaningful cut-point improvement.
Confirm feed pressure at the cyclone manifold, not at the pump discharge. Line losses can mask a low-pressure problem.
3. Apex diameter drives underflow behaviour
The apex diameter controls the underflow rope shape. A tight, controlled rope means good cut point; a wide, flooding underflow means bypass; a spray means the apex is worn or wrong.
Apex inserts are the fastest-wearing part of any cyclone. Inspect them at every shift on abrasive service.
4. Where cyclones wear
- Apex insert — first and fastest. Change on any visible rounding or size increase.
- Vortex finder — second-fastest. Wear here shifts cut point coarser.
- Cone body wall — slowest, but eventual replacement is required.
- Feed inlet — abrasion at the tangential entry can create bypass flow.
5. Sizing the bank
Total cyclone capacity should match the circulating pump rate at design feed pressure. Undersize and cyclones are bypassed by valve throttling; oversize and cyclones run partially loaded with degraded cut points.
Design for the peak circulating rate on the deepest, coarsest section of the programme — not the average.
Field Insight
Cyclone bank underperformance is almost always apex wear or wrong apex size for the actual solids loading. A ten-minute apex change on a night shift can restore a full section's worth of cut point.
- Feed pressure at the cyclone manifold — verify it, don't assume it.
- Apex geometry drives everything downstream: cut point, underflow, wear rate.
- Apex inserts wear fastest; inspect and change on schedule.
- Size the bank to peak circulating rate on the worst interval.
- A worn cyclone doesn't stop working — it just quietly cuts coarser.