During the Hydraulic Breakdown Prevention Workshop mentioned above, one of the attendees, a maintenance manager for a large open-cut mining operation, mentioned that he was considering upgrading the filtration on their fleet of hydraulic mining shovels - to achieve a higher level of fluid cleanliness.
There's no shortage of documented evidence to suggest that increasing hydraulic fluid cleanliness increases the service life of hydraulic components - all other things equal. Whether such an initiative would yield an acceptable return on the investment required, for the machines in question depends on a number of variables, which I don't have room to go into here. But this got me thinking about a bigger issue.
The maintenance routines I teach in my books and Workshops are about equipping people with the
knowledge the need today to optimize the reliability and service life of the hydraulic
equipment they have right now. And that's fair enough - it's rarely helpful and not very instructive to tell someone what they should have done yesterday. With this is mind, one of the exercises we do during my one-day Workshop is carry out a maintenance and reliability audit on an existing hydraulic machine.
Even though equipment design and equipment maintenance are often viewed in isolation, the reality is, certain aspects of hydraulic machine design have a significant impact on the machine's operating cost and reliability, and ultimately, its life-of-machine cost.
Over lunch, the same maintenance manager mentioned that his mine is starting to think about the replacement of their aging fleet of hydraulic shovels. And it occurred to me, the best time to carry out a maintenance and reliability audit on a piece of hydraulic equipment is BEFORE you buy it.
By starting with the end in mind, you get the maintenance and reliability outcomes you desire - before the machine even gets delivered. For example:
You specify the contamination control targets you want to achieve based on your reliability objectives for the piece of equipment. And instruct the manufacturer to deliver the machine appropriately equipped to achieve these targets.
Based on the weight and viscosity index of the hydraulic oil you plan to use, you determine the minimum viscosity and therefore the maximum temperature you want the machine to run at. And instruct the manufacturer to deliver the machine equipped with the necessary cooling capacity, based on ambient temperatures at your location. Rather than accepting hydraulic system operating temperatures dictated by the machine's 'design' cooling capacity - as is the norm.
If you don't think the viscosity/temperature issue is this important - you're mistaken. Lubrication failure resulting from low fluid viscosity is one of the biggest causes of premature failure in hydraulic components. If you're not on top of this issue it could be costing you big.
And we could continue by specifying things like flooded inlet for all pumps and so on. But you get the idea.
So the next time you or the company you work for are looking to acquire hydraulic equipment, begin with the end in mind. Define your maintenance and reliability objectives in advance and make them an integral part of your equipment selection process.
"This book has the potential to save many
organizations lots of m0ney. It should be on the bookshelf of every engineer, supervisor, planner and
technician that deals with hydraulic equipment... it's worth its weight in gold." Find out more
Alexander (Sandy) Dunn
Plant Maintenance Resource Center