Cement and Steel: Fans, Mills, Gearboxes and Slurry Pumps — Monitoring That Survives Dust

Cement plants in Vietnam and Southeast Asia are mostly 2,500–10,000 t/d dry lines; steel plants range from EAF mini-mills to integrated works. Both share a rotating-equipment population that is large, hot, dusty and critical: ID and preheater fans whose failure stops the kiln; raw and cement mill drives with gearboxes worth more than a mid-size pump station; cooling-water and slurry pumps; and hundreds of belt-conveyor drives. Route-based vibration rounds are hard to keep up in dust and heat, and the fault signatures are often masked by process noise. The way through is to pick the technology by machine, not plant-wide.

Match the technology to the asset

Asset	Dominant failure	Best first technology	Second
ID / preheater / cooler fans (up to several MW)	Unbalance from dust build-up, bearing wear, misalignment	Wireless vibration on both bearings (i-ALERT) with trend alarms — build-up shows as a steady 1× rise	Electrical signature at the MCC for the motor
Mill main drives and gearboxes (ball, vertical roller)	Gear-tooth and bearing damage, oil contamination	Online oil-quality and wear-debris sensors on the circulating lube system (Poseidon Trident)	Vibration for fault location
Kiln drive and girth-gear lubrication	Pinion/girth gear wear, lube system faults	Oil and grease condition monitoring; vibration on pinion bearings	AI camera for lubricant spray and leaks
Slurry, cooling-water and raw-water pumps	Seal and bearing failure, cavitation	Drive-based operating-point protection (ReliaPump) where on VFD; vibration	Seals matched to slurry duty
Large MV motors (fans, mills, compressors)	Rotor bar cracks, stator insulation, supply unbalance	Electrical signature analysis in the MV switchgear (ESine4)	Vibration
Conveyor drives and gearboxes (hundreds)	Gearbox failure, belt issues	Low-cost wireless vibration on the worst 10 %; ESA for the rest from MCC	AI camera for belt tracking and spillage
Bag filters, compressors, blowers	Bearing failure, overheating	Vibration and temperature (i-ALERT)	—

Fans: the cheapest high-value installation

A kiln ID fan failure costs a day of clinker. Its failure mode is predictable — dust accretion on the impeller produces unbalance that grows for weeks, then a bearing starts to go — and visible in vibration long before anyone hears it. Two i-ALERT sensors per fan (drive-end and non-drive-end bearing) with alarms at 1.5 times the clean-fan baseline give the maintenance planner weeks of notice to schedule a clean and balance at a kiln stop rather than an emergency. The motor gets ElectroSine in the MCC, which also reports voltage unbalance — a common silent killer in plants with long MV feeders.

Mill gearboxes: oil sees it first

A vertical roller mill or ball mill gearbox is a multi-million-dollar asset with a lead time of a year. On the P-F curve, wear debris in the oil is the earliest sign of gear or bearing surface fatigue, weeks to months before vibration spectra change in a noisy mill environment. A Trident wear-debris monitor on the return line and an oil-quality sensor on the supply, both on an isolatable branch installed at a planned stop, report daily; the lab sample stays as confirmation. Steel plants apply the same to rolling-mill gearboxes and pinion stands, where the environment is similar and the stakes higher.

Making vibration data readable in a noisy plant

• Baseline per machine and per operating state (mill loaded/unloaded, fan damper position). Alarms on trend and rate of change, not absolute ISO limits alone.
• Mount sensors on clean, flat, magnetic surfaces close to the bearing; dust-covered or painted curved housings attenuate the high frequencies that reveal bearings. Stud mounts on fans.
• Use acceleration and bearing indicators for bearings, velocity for unbalance and alignment; a rising velocity with a stable bearing indicator on an ID fan is almost always build-up.
• Let PlusSmart engineers do the FFT diagnosis remotely; the plant team acts on the recommendation, not on the spectrum.

Where AI cameras help

Cement and steel plants have hazards that no vibration sensor sees: hot-material spills, conveyor fires, missing PPE near kilns and furnaces, people in restricted zones around tipplers and cranes. PlusVision runs detection at the edge on existing or new cameras and raises alarms in SCADA — leak and spill detection at pump bays, smoke at bag filters and coal mills, intrusion into red zones. It complements, rather than replaces, certified safety systems.

Starting point

Send PlusSmart Vietnam the list of fans, mill drives and gearboxes with their failure history. The proposal is typically: sensors on the kiln and preheater fans, oil monitoring on the two main mill gearboxes, ESA on the MV motors, and a Pump Health Check on the water and slurry pumps — staged so the first results arrive before the next kiln stop.

Quick answers

Do wireless sensors work on large fans with thick housings?

Yes, mounted on the bearing pedestal close to the load zone with a stud or strong magnet on a clean flat surface. Avoid guards and covers; the signal path must be solid metal to the bearing.

Can oil monitoring be fitted to a splash-lubricated gearbox without a circulation system?

Yes, with a small kidney loop — a pump that passes oil from the sump through the sensors and back. PlusSmart specifies the loop and mounting point for a planned stop.

Can ESA monitor medium-voltage motors?

Yes. ESine4 performs full three-phase analysis of MV and LV motors using the switchgear CTs and VTs, including unbalance, negative sequence and NEMA/IEC derating, interpreted by PlusSmart engineers.