I have a confession to make|
One of the reasons you should be reading this newsletter is so you don't have to learn things the hard way.
The story in last month's issue about the mechanic who turned a double-acting cylinder in to a
rocket launcher jogged the memories of a few old hands.
Oxygen and fuel gas is extreme to say the least, but using compressed air is just as dangerous. As one of our members explains:
"In my case it was the tube that made the trip across the mill yard. It's amazing how much stored energy there was in that thing. I had the compressor turned up to over 230 PSI the last time I looked."
Yep, assuming you get away with it, it's the sort of thing you only ever do once. I have to confess I did it and almost didn't - get away with it I mean. It wasn't my idea. But I was too young and inexperienced to understand the consequences.
We had the cylinder vertical in a gantry with a chain block on the rod but it wouldn't budge. My supervisor appeared and suggested connecting the air hose to the dead-end port. Like I said, I was still wet behind the ears, so did as instructed.
The result was quite spectacular. The piston-rod took off like Apollo 13. NASA would have been proud. Laugh if you like, but I wasn't laughing at the time. Because what goes up must come down. And had I been standing two feet to the left, well, it's a pretty sure bet I wouldn't be writing this today.
Due to the broad cross-section of people who read this newsletter: hydraulic equipment owners - large and small; industry professionals; mechanics, maintenance hands and students, it's almost impossible for me to directly address every group in every issue.
As a result, our newer members may sometimes wonder what we're about here. This for example, from a new member from Ireland:
"You may be aiming for the big fish that's understandable. But I'm a two machine man and two small machines - a JCB digger and a Thwaites dumper. So I'm only interested in matters that are relevant to me."
Actually, this is the type of equipment owner I had in mind when I sat down to write Insider Secrets to Hydraulics six years ago. And here he is again, but this guy owns just one hydraulic machine:
"The horizontal drill rig I am running is a special. We blow pumps and motors all the time to the point where we try to carry spares. When out of state I have to rely on someone who knows you need it now and you don't live nearby.
I just put three new pumps on my machine and no power. Called the dealer and no one could help. Searched the web, got a breakdown on them, bought a gauge to find out they didn't set pressures even though the tags said so.
Had valves rebuilt, put them on to find they didn't work. Started investigating to find out I got a paint job for $3000. Still broken parts in them.
Pump dealer rebuilt my pump, put it on, bogged my engine down. They couldn't figure out what was wrong with it. Called my mechanic in Texas, who told me he was pretty sure they forgot to put plug and orifice in - sure enough.
My machine is running around 130 degrees and no one can tell me the correct hydraulic fluid to use. So I'm trying to learn enough to problem solve, and keep things going."
All I'll say here is, if any part of this story resonates with you, you'll love Insider Secrets to Hydraulics. Because after six years I've never heard from a hydraulic equipment owner - large or small who hasn't. And if every owner who read it cut me a check for half of what they saved afterwards I wouldn't be too far behind Bill Gates and Warren Buffet. So if you haven't read it yet, put it on your Santa list.
Whoops, is that a self-serving statement? Sure it is. But if you're a hydraulic equipment owner, getting and reading Insider Secrets will do a lot more for you than it will me.
And if any of what I've just said offends you in any way, scroll down and remove yourself from this list. Anyone who prefers ignorance to knowledge is not welcome here.
Speaking of the big fella in the red suit reminds me this is the last issue for 2008. Another year draws to a close. A new one ahead.
It seems to me many people's new years resolutions are made ruefully or in jest, with hope for a better year. But hope is not a strategy. And so for these folks the new year unfolds pretty much like the old one.
For anyone who'd appreciate a brain-starter, here's my new years resolution "check-list": Strive to get smarter. To do a lot of things better. To do at least one thing so well no one else can match your skill. Set, pursue and achieve a lot of goals. Resist the status quo and ignore less creative or ambitious peoples' criticisms or disapproval.
The Nice Things People Say …
"The knowledge I've gained from this information has been
so valuable it has earned me a raise!"
Find out more ...
Heavy Equipment Mechanic
Back to basics: troubleshooting tools|
This one's relevant to our machine owner members and pretty much everyone else too:
"What is the most effective and efficient method to diagnose internal leakage on mobile construction equipment; e.g Backhoe or Skid Steer Loader - without the aid of diagnostic tools, such as pressure gauges and flow meters."
It's not a bad question, but upon deeper analysis it smacks of 'silver-bullet' seeking. The revealing phrases are "most effective and efficient method" and "without the aid of...pressure gauges and flow meters".
It's human nature to seek maximum gain from minimum effort. Even if it's not realistic. And since my job here is to entertain as well as inform, I'll give you my 'silver bullet' answer first:
I've developed and patented a special troubleshooting paint. So now when a hydraulic problem arises, all you have to do is shake said can well and spray any hydraulic component you suspect might be faulty. After a couple of minutes faulty components turn red and serviceable components turn green.
It's a nice fantasy. About my early retirement I mean.
So to qualify the question before I answer it, until I perfect my magic spray paint: the most efficient method of troubleshooting may not be the most effective, and the most effective not the most efficient - which I assume is the reason for excluding pressure gauges and flow meters when posing the question.
But there are other tools and techniques we can employ when troubleshooting. One of these is the infrared thermometer or heat gun. The equipment required is inexpensive, its application is quick and non-invasive and the results can be very revealing.
It's usefulness in hydraulic troubleshooting comes about because when hydraulic fluid moves
from an area of high pressure to an area of low pressure (pressure drop) without performing
useful work, heat is generated. For a more detailed explanation of this concept,
watch this video clip.
This means components with abnormal leakage generate abnormal heat. So a double-acting cylinder with a leaking piston seal or a relief valve that is passing usually become hotter than the rest of the system. And an infrared thermometer will quickly reveal them to you.
But like most other tools, an infrared thermometer is only as good as the person using it. And so you do have to be careful of false positives. The objective of every troubleshooting exercise should be to prove a component is faulty before it is changed-out. This is normally accomplished through a logical process of elimination.
An infrared thermometer can certainly speed up this process, but if the data coming from it doesn't make sense or is not conclusive, then other tools should be employed to eliminate any doubt.
For example, a recent client came to the conclusion that a solenoid valve was the cause of his problem - based on temperature measurement alone. But there were two problems with this diagnosis: Firstly, a solenoid valve tends to absorb heat from its coil when energized - which could explain its temperature rise. And secondly, in the context of the particular system it didn't really make sense.
I explained we should note his observation but continue the troubleshooting process - using other tools as necessary - to prove the diagnosis one way or the other. Because a false positive is just as bad as a blind guess - it results in the unnecessary change-out of serviceable components. Something you want to avoid.
"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
What would YOU do in this situation?|
It's Sunday morning. You get a call from the maintenance manager at a nearby power generating plant. He tells you he has a serious problem. While bringing one of their turbines back on line after scheduled maintenance, they have discovered many leaks from the tube fittings in the EHC hydraulic system.
The hydraulic fluid is aggressive, phosphate-ester type which is harmful to humans. It is leaking into a critical containment area. In an attempt to stop the leaks, each fitting has been re-tightened without success. Their scheduled maintenance period will soon expire. Each day of additional downtime will cost the company millions in lost revenue.
How would you handle this situation?
Click here to find out what actually happened.
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About the Author: Brendan Casey has more than 19 years
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