I was interviewed on national radio last month. Don't worry, it was nothing to do with hydraulics. As if national media would be interested in the technical challenges we concern ourselves with on a daily basis.

No, I was on the airwaves talking about my recently published children's book, Farmer Mick Harvest Time Havoc. When asked about my father, who was the real Farmer Mick, and the inspiration for the main character in the story, I mentioned the fact that, in addition to his many fine character traits, Dad could be a real S.O.B. at times.

After the interview my wife Jay suggested that I probably shouldn't have mentioned that my father wasn't perfect. After all, I was being interviewed about a children's story book and so best to keep everything warm and fuzzy, right?

But that's not the way it was. And were I to pretend otherwise, I figure I'd have been pegged as a phoney pretty quickly. Besides, it's my observation that if you plan on achieving much in life, you need to have zero tolerance for road blocks, be they people or anything else. Patience is an asset when dealing with children and old people; it's much less of an asset when you're determined to get stuff done.

The real Farmer Mick was a very successful farmer. He always had a clear idea of what he wanted to do and how and when he was going to do it. And heaven help you if you got in his way. Most of the successful people I know are the same. This is not to say it's necessary to steam roll everyone or everything that poses an obstacle-only the ones you can't side step.

Lest you get the wrong lesson: I am NOT advocating road rage against your fellow motorists or any other unreasonable behavior. What I am suggesting is it's OK to have an ingrained intolerance for anyone or anything that slows or prevents you from moving towards your personal or professional goals.

What's this got to do with hydraulics? Nothing. And EVERYTHING. The reason I champion certain philosophical positions here, and in my Hydraulics Pro Club newsletter is because I am conscious of the futility of sharing "mechanics" with people without addressing internal barriers to their success.

For example, in response to last month's newsletter where I reported on the trend towards multi-skilled trades people, one member wrote me to say, in effect, this is all bad and a typical trades person will never get a return on the time and money she is expected to invest in herself to become multi-skilled - because in the end, she's still only be a lowly-paid trades person.

That's baloney. But if someone on a certain rung of the ladder believes that's where they belong and that's where they should stay, they no amount of hydraulics knowledge I can impart is going to improve their lot in life.

So I'd be intellectually dishonest if I didn't devote some time and space in my writings to the discussion of 'success factors'. That said, I realize some people react skeptically - "hey, this isn't what I signed up for". But knowledge without capability, self-belief, get-up-and-go, chutzpah or whatever you'd like to call it, is useless.

The Nice Things People Say ...

"A farmer has an older tractor and the lift arms don't work. One mechanic went through the pump and control valve, still didn't work. Another mechanic rebuilt the lift cylinders, still didn't work. Next, the farmer brought it to me and thinking of your advice to check the simple things first, one can of penetrating oil and 30 minutes later, it was working. The linkage was froze up. Felt sorry for the old feller, so no charge. But he told everyone and now my shop is full!" Find out more ...

Doc Bess
Carolina Preventive

2.	Filtration: can you have too much of a good thing?

Additive depletion is one of the ways hydraulic oil gets 'spent' and in doing so, necessitates an oil change. Other than keeping the oil (relatively) cool and dry, there's not a lot we can do about additive consumption. But losing additives through over zealous filtration is another matter entirely. Consider this question from one of our members:

"If I filter hydraulic oil with a kidney-loop unit down to half a micron, will I lose some of the additives?"

Before I attempt to answer this question, is filtering hydraulic oil down to 0.5 microns sensible or even warranted? For 90 percent of (non-critical) hydraulic systems out there, probably not.

Even for critical, servo-valve systems, filtration of 2-micron absolute is generally considered adequate. So for the vast majority of systems, you have to question the benefits of sub-micron filtration - particularly when you take into account the COST of doing it. Just because sub-micron filtration technology is available - it doesn't automatically mean its use is justified on a cost/benefit basis. If it is, great. If it's not, don't do it!

But can oil additives be removed by fine filtration? It depends-on the filter or filtration process being used and the type of additive.

The first thing to keep in mind is most of the additives in hydraulic and lubricating oils should be dissolved in the base oil. This means they should NOT be in suspension in the oil and therefore, should NOT be captured by conventional depth filters - even fine ones.

There is at least one notable exception though. De-foamant additives are suspended rather than dissolved in the oil and so they can be filtered out. As can any other additives that are not properly dissolved in the oil for any reason.

But conventional depth filters aren't the only form of fine filtration available. It's generally accepted that absorbent type filters which consist of chemically active materials such as activated alumina, fullers earth, active clays, charcoal and chemically treated paper can remove additives from the oil.

Some references assert there is a risk of additive removal with centrifugation, while a research paper I read recently concluded that centrifugal filters installed on diesel engines do not remove soluble additives from the oil.

As you can see, this issue, like many others in hydraulics, is not black and white. But as I mentioned at the beginning, any risk of additive removal can be avoided by not filtering the oil beyond the level justified by the application. And in the vast majority of hydraulic applications where the installed level of filtration is 5 microns or above, the risk of additive removal is virtually non-existent.

"This book has the potential to save many organizations lots of money. It should be on the bookshelf of every engineer, supervisor, planner and technician who deals with hydraulic equipment... it's worth its weight in gold." Find out more

Alexander (Sandy) Dunn
Plant Maintenance Resource Center