Lube-Tips

Failure Triage Classifications (3 Tees)

• Trivial – incipient (about to occur)
• Treatable – impending (is occurring)
• Terminal – catastrophic (has occurred)

We know that when critical failures occur, every effort should be made to prevent repeat performances. Yet, without an intervention to remove the underlying root cause, a recurrence is almost guaranteed. Maintenance organizations should consider failure investigations as seriously as they do immediate repair. Yet all too often, once production is restored, the urgency and memory of the failure begin to fade.

Ferrous Density Meters and the Canaries

Ferrous density meters can foretell disastrous events just like canaries in a coal mine. These instruments can often save a machine from sudden operational failure. Their role is to monitor the density of a single type of wear metal commonly found in oil or grease: cast iron or low-alloy steel. Such common metallurgy is deployed in a wide range of frictional machine surfaces including bearing rolling elements/ raceways, gears, pistons/cylinders, cams/followers and many others.

Hope to Inspect a Gearbox

Although a comprehensive on-site gearbox inspection is desirable in many situations, there may be constraints that limit the extent of the inspection such as cost, time, accessibility and qualified personnel. Quick but effective gear inspections:

• Visual: pitting, scratch marks, polishing, etc.
• Touch: shelf formation
• Measure: backlash with a feeler gauge
• Debris: magnetic probe or BS&W

The Destructive Potential of Engine Oil

It only takes one litre of engine oil to destroy the demulsibility of 6000 litres of turbine oil. Lubricants that require good demulsibility (water separation) should never be mixed with lubricants that contain dispersants or high concentrations of detergents. Small amounts of oil with good emulsion characteristics will destroy the water-shedding properties. Rarely can the demulsibility be restored.