Rising torque means cake is accumulating faster than the scroll can convey it. Left alone it ends in a packed bowl — a hard stop, possible scroll or bearing damage, and hours of downtime to dig out.
Likely causes
Bowl packing / cake build-up — solids entering faster than the scroll removes them. The classic cause.
Feed rate too high for the duty — loading the bowl beyond its conveying capacity.
Pool (weir) set too deep — longer clarifying, but a heavier cake load on the scroll.
Inadequate flush at shutdown — last run’s cake left to harden in the bowl.
Scroll flight wear — worn flights convey less per turn, so torque climbs at the same load.
How to diagnose it
Trend the ammeter against feed rate — if torque tracks feed, you’re overloading the bowl.
Confirm flush-at-shutdown is logged every shift.
Check pool/weir depth against the duty (barite recovery vs dewatering).
Inspect the discharge: a dry, packed cake vs free-flowing solids.
Review the differential (back-drive) setting against the duty chart.
The fix — step by step
Step the feed rate down until torque stabilises — within conveying capacity.
Set one duty, not a compromise: barite recovery (lower G, coarser cut) or fines/dewatering (higher G).
If cake load is the issue, set the pool shallower.
Enforce flush-to-clean at every shutdown — and log it.
If torque is high at normal feed, schedule a scroll inspection for flight wear.
Confirm it's fixed
✓ Verify: Torque returns to baseline and holds steady at the target feed rate, with a free-flowing (not packed) discharge. Trend it for a full shift before you call it fixed.
Field note. Catch it on the trend, not the alarm. Torque is a leading indicator — a steady climb over an hour is the warning; the alarm is already late. The cheapest centrifuge repair is the one the ammeter lets you prevent.