Who Are You Calling Aggressive?

What’s aggressive in one context might not be in another. Flour on a bakery floor isn’t aggressive. Flour in a bearing is. If it finds its way through seals and combines with lubricant, the resulting paste will grind into the bearing, causing excessive wear and, ultimately, bearing failure. 

Many failure modes in aggressive environments have a very sharp failure curve. By the time traditional Condition Monitoring solutions have flagged-up an issue, much of the damage is already done. So before you think about Condition Monitoring, there are other ways to give your assets a fighting chance against even the most aggressive operating conditions.

A clean sweep

Hostile environments for machines are quite often a result of a process within an industry.  The machine manufacturers are aware of the possibility of creating such an environment and hence specify their equipment accordingly. Over time though, containment measures wear and equipment is at higher risk of asset failure. So good housekeeping can make a difference.

It may not be possible to avoid producing contaminants. But they don’t have to cause a problem.

Dust can be damped down with sprays or extracted with extractor fans so it doesn’t escape into the wider operating environment. Conveyor belts can be fitted with surfaces which prevent offending substances from falling off. Anything which does escape should be cleaned-up immediately. Elements of the process which create most dust should be contained, making the aggressive environment smaller and more manageable.

With a combination of these measures, even the dirtiest process can clean up its act to the benefit of its operating environment and the equipment within it.

But it’s also good to question why the equipment is there in the first place.

If you can’t stand the heat…

Just because an asset is part of the process which is creating the aggressive environment, it doesn’t mean it physically needs to be in that environment.

Using a longer driveshaft to connect a gearbox to its motor, for example, makes it feasible to move the motor out of the aggressive environment, yet still have it driving the gearbox inside. Driveshafts of up to 10m in length are entirely possible if engineered-in at the design stage, so there are few applications where it’s impossible to create enough distance for the motor to be situated somewhere cleaner.

For the gearbox which remains in the aggressive environment, lubrication is an effective defence against contaminants. It reduces the friction that can result if contaminants enter moving parts, and it offers a medium which can be monitored for early warning signs of contamination. For example, some sensors can detect as little as a teaspoon of water in a litre of oil.

Performing seals

If you’ve done everything you can to keep your operating environment clean and free from contaminants, and you’ve moved vulnerable assets out of the aggressive environment, then your next course of action is to look at the assets themselves.

Even if your motor isn’t operating in an aggressive environment in the strictest sense, it could still be affected by aggressive contaminants.

For example, a crusher clearly operates in an aggressive environment but, strictly speaking, the motor driving the conveyor belt from the crusher doesn’t. However, if contaminants from crushing are not sufficiently contained, effectively extracted or otherwise removed, they will spread, the aggressive environment will extend, and now your motor will be within it. If it only has a standard IP rating, it won’t be long before its performance and reliability are affected.

But let’s say you’ve established the cleanest operating environment you can. You’ve moved whatever assets you can out of harm’s way. And you’ve correctly specified the IP rating of those assets that unavoidably come into contact with contaminants.

Now what else can you do to maximise reliability, and reduce downtime and critical failures? It’s time to employ the third line of defence.

Defence of the last resort

When all other options have been exhausted, it may be time to consider moulded-oil bearings and super seals to increase protection against contaminant ingress, or to look at automatic lubricators such as the Simalube, which place positive pressure on the lubricant within the bearing, to help keep out contaminants.

Then it’s time to think about Condition Monitoring

Given the sharp failure curve within aggressive environments, traditional periodic portable monitoring will not be effective. Instead you should consider live data acquisition through real-time online monitoring, and ERIKS eConnect, to enable you to identify issues soon enough, such as when debris, dust or fluid has increased, to avoid them creating critical failures.