Monitoring oil, managing risk

Analysing hydraulic lubricants to detect wear metals is not a new concept for Australian manufacturers, but Scott Gilroy from PANalytical believes the local use of X-ray fluorescence (XRF) technology to detect wear metals in hydraulic lubricants is set to increase.

ProcessOnline spoke with Gilroy to investigate Australian trends in oil analysis compared with overseas manufacturers and the technologies currently available. He provides his opinion on why condition monitoring of oil is crucial for manufacturers when it comes to managing risk.

What is condition monitoring?

What we're looking at is what we call wear metals. This involves the condition monitoring of oil progressively over time. For example, if we look at the big Caterpillar mining trucks. They've got powerful engines that use many litres of oil and so the users try to prolong the life of the oil. They use it until its very last point, and then change it so they save themselves money.

With the actual tracking of the wear metals in oil, what you're looking for is a depletion in additives, or an increase in wear metals. That's the key. If your additives wear down then you're not getting the benefit of the coating on the engine parts and you're getting more wear.

What you start to see in the process is: as the additives go down, the wear metals go up. You get to a point where if your additives drop completely, your wear will significantly damage your engine.

Also, by continuously monitoring your oil and knowing where the wear is coming from, you can identify which gear is likely to fail, which gear will need replacing or what piston is wearing. You can then start to determine which part of the engine is actually having difficulties. This means you can replace that part to prolong the life of the machinery. That's what condition monitoring is designed to do.

How does the technology work?

The newer XRF technology is often used in the wear metals markets. Competing technology such as ICP actually has difficulty detecting large particles [greater than 10 micron]. With XRF, you're not actually putting any substance into the machine and so you don't have difficulties with large particles.

ICP was the old standard that everyone used - every oil industry manufacturer had an ICP or used some sort of ICP, but now they're moving to XRF.

Condition monitoring is about trend and controlling the trend, especially for wear metals. It really doesn't matter if iron is at 200 ppm or 2000 ppm. It's about the change: where it started at and where it is at now. If it moved from 200 to 220 ppm, that progressive change indicates the progressive degradation of your components.

So every system will have a totally different set of parameters they are testing to?

Yes, as it depends on what oil they're using as well as the machinery it is being used in. One of the customers we had using our analysis system was controlling the level of aluminium oxide in the system.

When the machine was wearing, the aluminium oxide would slowly increase from 1 to 20 ppm, and once it hit 20 ppm he had to change the oil. So he was just monitoring that change and increase in the aluminium in the oil. That's predominantly what it's all about, regardless of the concentration.

Parameters are different for every business, for every oil. There are some standards in basic lubricating oils that will indicate what's in there, but it's really what a manufacturer is looking for and looking to do with the oil.

If you put it into a machine with copper and nickel bearings, then you're looking for a trend for wearing of copper and nickel. But if you put it into another machine with iron, then there's no point looking for copper and nickel. Its operator dependent and it's based on what's inside the machine.

There's a range of different suppliers in this industry and the technology will be slightly different depending on whether their machine uses wavelength or energy dispersive XRF technology.

Wavelength dispersive gives them lower concentration ranges, so if they're looking for elements at really low levels we take a wavelength dispersive machine. If you're looking for elements slightly higher in concentration, we take an energy dispersive.

Wavelength technology is faster and more powerful and energy dispersive systems are generally smaller and lower powered. The other thing to consider is that wavelength dispersive systems can sometimes damage a sample because they are so high powered.

Are there any testing standards that manufacturers must follow?

When you're talking about wear metals and condition monitoring, there's not really standards as such, because you're looking at trend processes.

It's up to the manufacturer to make the decision on how long they will leave the oil in the machinery in comparison to the wear. It's their call - their business risk management.

What is the current uptake of the technology by manufacturers?

The uptake in the refineries is very big. All the refineries use XRF technology because it's quick, it's easy, there's less damage to the machinery and it doesn't cost as much over time to run.

A lot of hydraulic customers that are controlling their oil process actually ship their oil to external labs to be tested because it's not always viable for them to do the testing in their own environment.

They may only have one or two samples a week, so they send it off to a service laboratory to test the samples and do the statistical process for them. The lab will let them know where their engine is up to and where it's wearing.

The uptake has been slower in Australia than overseas, where it has already boomed. I think that's just because we went through a phase a few years ago where everyone started to buy machines and they can't reinvest in new technology yet.

Are there manufacturers out there that aren't analysing their hydraulic lubricant at all?

Yes. They may be just changing their oil every six months and not looking at the potential saving or what damage may be happening to their machines.

You don't see that damage in a six-month period, and they don't see it over a year. They may see it in two years or three years, when their machines start to fall apart and they wonder why.

Then a manufacturer will face a lot of costs, and that's when you see many of the smaller businesses going out of business, because they haven't managed the risk earlier.

There will come a time when such manufacturers will wake up and say "we've got to start doing this". And this may be too late for the smaller businesses. The bigger ones can cope, but the smaller businesses generally can't. Once the big equipment falls apart, they've got to spend or take out another loan.

It's been said that many users are not using condition monitoring systems effectively? What's the answer to this?

Better training helps. You need to provide a system where you take the customer through and say "this is the process you've got to follow". And a lot of people don't understand that process.

How you get them to understand the process can be difficult. Unless you can get them to see the benefit at the end, the work beforehand drops off. If they don't stick with correct procedures, of course they're going to have problems.

There's really not much more you can do on that front with a lot of businesses, because some just like to say they've got the procedures in place, whether they follow them or not.