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Senin, 30 Agustus 2010

Air, patience is a virtue, however...

Air,

If you missed the August issue
of 'Inside Hydraulics',
it's available online at:
http://www.hydraulicsupermarket.com/aug.html


Best Regards,

Brendan Casey
HydraulicSupermarket.com

==========

If you no longer wish to receive the valuable guidance
provided by the 'Inside Hydraulics' newsletter
and associated mailings, point your browser to this page:
https://hydraulics.infusionsoft.com/opt?o=2&i=123560&m=775858&e=c893403f

HydraulicSupermarket.com
1195 Hay St
PO Box 1029
West Perth, WA 6872
Australia
6 (189) 380-6659

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Minggu, 29 Agustus 2010

Air, get your cylinder rods straight

Hello again Air,

In your last hydraulic maintenance email, I wrote
about the problems that can occur if case drain
lines from piston pumps or motors are filtered
or otherwise restricted.

Today I want to switch gears and talk about a major
cause of rod-seal failure in hydraulic cylinders.

As a product group, hydraulic cylinders are almost
as common as pumps and motors combined. They are less
complicated than other types of hydraulic components
and are therefore relatively easy to repair.

As a result, many hydraulic equipment owners or their
maintenance personnel repair hydraulic cylinders themselves.
And this is why I included a whole chapter about carrying
out effective repairs on hydraulic cylinders in my book,
'Insider Secrets to Hydraulics'.

An important step in the repair process that is often
overlooked by do-it-yourself repairers, is
checking rod straightness.

Bent rods place load on the rod seal causing distortion,
and ultimately premature failure of the seal.
So rod straightness should always be checked when
hydraulic cylinders are being re-sealed or repaired.

The procedure for doing this is explained in detail
on pages 82 and 83 of 'Insider Secrets to Hydraulics'
http://www.hydraulicsupermarket.com/books.html


In most cases, bent rods can be straightened in a press.
It is sometimes possible to straighten them without
damaging the hard-chrome plating, however if the chrome
is damaged, the rod must be either re-chromed or replaced.

BUT a word of CAUTION before I go.
Attempting to straighten induction-hardened rods
can cause the hardened case to shatter - with
the potential for serious personal injury and/or
property damage.

For this reason, before attempting to straighten
any cylinder rod - make sure it hasn't been
induction-hardened first.

Yours for better hydraulics knowledge,

Brendan Casey
Author of 'Insider Secrets to Hydraulics'; and
'Preventing Hydraulic Failures'.
http://www.hydraulicsupermarket.com/books.html
=======================================


If you no longer wish to receive the valuable guidance
provided by the 'Inside Hydraulics' newsletter
and associated mailings, point your browser to this page:
https://hydraulics.infusionsoft.com/opt?o=2&i=123560&m=776746&e=c893403f


==========

HydraulicSupermarket.com
1195 Hay St
PO Box 1029
West Perth, WA 6872
Australia
6 (189) 380-6659

Delivered By Infusionsoft

Senin, 23 Agustus 2010

Air, another filter that does more harm than good

Hello again Air,

In your last hydraulic maintenance email, I wrote
about the importance of following proper procedures
when re-starting a hydraulic system after carrying
out maintenance work - to avoid premature failures.

Today I want to clarifiy another myth, that causes
a lot of hydraulic problems - and even failures ...

Myth #5. All oil returning to the hydraulic reservoir
should be filtered.

True. With one VERY important exception:

The case drains of hydraulic piston pumps and motors.
Connecting case drain lines to return filters can cause
excessive case pressure, which has a number
of damaging effects.

High case pressure results in excessive load on
the lip of the shaft seal. This causes the
seal lip to wear a groove in the shaft,
which eventually results in a leaking shaft seal.

The effect of high case pressure on in-line
piston pumps is the same as excessive vacuum
at the pump inlet. Both conditions put the
piston ball and slipper-pad socket
in tension during intake.

In severe cases this can result in buckling
of the piston retaining plate and/or separation
of the bronze slipper from the piston,
causing major failure.

Under certain conditions, high case pressure
can cause the pistons of radial piston motors
to be lifted off the cam during outlet.
When this happens, the pistons are hammered back
onto the cam during inlet, destroying the motor.

For the reasons described above,
conventional depth filters are generally
NOT recommended on case drain lines.


For more on these and many other hydraulics tips,
point your browser to:
http://www.hydraulicsupermarket.com/technical.html


Yours for better hydraulics knowledge,

Brendan Casey
Author of 'Insider Secrets to Hydraulics'; and
'Preventing Hydraulic Failures'.

=======================================


If you no longer wish to receive the valuable guidance
provided by the 'Inside Hydraulics' newsletter
and associated mailings, point your browser to this page:
https://hydraulics.infusionsoft.com/opt?o=2&i=123560&m=775014&e=c893403f


==========


HydraulicSupermarket.com
1195 Hay St
PO Box 1029
West Perth, WA 6872
Australia
6 (189) 380-6659

Delivered By Infusionsoft

Selasa, 17 Agustus 2010

Air, would you start an engine with no oil in the crankcase?

Hello again Air,

In your last hydraulic maintenance email, I explained
how to add oil to a hydraulic system - without the dirt.

Today I want to clear up another popular misconception,
about the installation of hydraulic components ...

Myth #4. Because oil circulates through hydraulic components
in operation, no special attention is required during
installation beyond bolting the component on and
connecting its hoses.

Nothing could be further from the truth,
as this example illustrates:

I recently conducted failure analysis on a hydraulic motor
that was the subject of a warranty claim. The motor
had failed after only 500 hours in service, some
7,000 hours short of its expected service life.

Inspection revealed that the motor's bearings had failed
through inadequate lubrication, as a result of the
hydraulic motor being started with insufficient oil
in its case (housing).

After this motor was installed, its case should have been
filled with clean hydraulic oil prior to start-up.
Starting a piston-type motor or pump without doing so,
is similar to starting an internal combustion engine
with no oil in the crankcase -
premature failure is pretty much guaranteed.


For more on these and many other hydraulics tips,
point your browser to:
http://www.hydraulicsupermarket.com/technical.html


Yours for better hydraulics knowledge,

Brendan Casey
Author of 'Insider Secrets to Hydraulics'; and
'Preventing Hydraulic Failures'.

=======================================


If you no longer wish to receive the valuable guidance
provided by the 'Inside Hydraulics' newsletter
and associated mailings, point your browser to this page:
https://hydraulics.infusionsoft.com/opt?o=2&i=123560&m=773312&e=c893403f


==========

HydraulicSupermarket.com
1195 Hay St
PO Box 1029
West Perth, WA 6872
Australia
6 (189) 380-6659

Delivered By Infusionsoft

Air, multiple skill-sets required

Try 'Hydraulics Pro Club' for just $1
http://www.hydraulicsupermarket.com/pro.html


Air,

The hydraulics trade or profession is a big umbrella
over the top of a collection of different skill-sets
that have to be developed or acquired.

You need to know how it works - from simple 'bang bang'
circuits to increasingly complex variable-pump and
proportional control - so you can accurately identify
and correct problems without unnecessary component change-outs
that result from guessing.

You need to know how to use and apply an array of
diagnostic tests and tools: flow meter; heat gun;
the latest computer simulation tools and
everything else in between.

You need to know how to create and maintain
operating parameters which optimize machine productivity,
maximize reliability and reduce downtime.

You need to know how to minimize component repair
and replacement costs.

You need to know when a dollar spent on preventative
or proactive maintenance is a dollar well spent
and when it isn't. And how to determine the difference.

You need to know how to squeeze the most out of oil,
filters and other consumables.

And then of course, you need to keep all this know-how
up-to-date with the latest advances in technology.

In short, hydraulics is not a simple, single skill-set craft.
Hardly any specialization is that simple, but a number of
trades or professions can be much simpler.

People enjoying high 5-figure and 6-figure incomes
as hydraulics specialists have developed a broad range
of skills, are continually learning and improving their skills,
and invest significant sums of money in on-going skill development.

The inconvenient truth is that this craft is NOT for everybody;
and it is definitely the wrong field
for the intellectually lazy individual.

But for anyone willing to step up to the plate,
an interesting and well-paid career is their reward.

Yours for better hydraulics knowledge


Brendan Casey

Try 'Hydraulics Pro Club' for just $1
http://www.hydraulicsupermarket.com/pro.html

=========


If you no longer wish to receive the valuable guidance
provided by the 'Inside Hydraulics' newsletter
and associated mailings, point your browser to this page:
https://hydraulics.infusionsoft.com/opt?o=2&i=123560&m=772976&e=c893403f

HydraulicSupermarket.com
1195 Hay St
PO Box 1029
West Perth, WA 6872
Australia
6 (189) 380-6659

Delivered By Infusionsoft

Rabu, 11 Agustus 2010

Air, how clean is new oil - really?

Hello again Air,

In your last hydraulic maintenance email, I corrected
a popular misbelief about the cause of cylinder creep.
A lot of people struggle with this one because it's
the exact opposite of what they've been conditioned to
believe.

Here's another great lie ...

Myth #3. New hydraulic oil is clean hydraulic oil.

New hydraulic oil straight from the drum, has a
typical cleanliness level of ISO 4406 23/21/18.

Now that number may not mean a lot to you, but it's
four cleanliness code levels below that considered
ideal for a high pressure, high performance hydraulic
system.

Looking at it another way, a 25 GPM pump operating
continuously in hydraulic oil at 23/21/18 will
circulate 3,500 pounds of dirt to the hydraulic
system's components each year.

To add hydraulic oil, and not the dirt,
always filter new oil prior to use in a hydraulic system.

This can be accomplished by pumping the oil into the
hydraulic reservoir through the system's return filter.
The easiest way to do this is to install a tee in the
return line and attach a quick-connector to the
branch of this tee.

Attach the other half of the quick-connector to the
discharge hose of a drum pump.

When hydraulic oil needs to be added to the reservoir,
the drum pump is coupled to the return line and the oil
is pumped into the reservoir through the return filter.

As well as filtering the oil, spills are avoided and the
ingress of external contamination is prevented.


For more on these and many other hydraulics tips,
point your browser to:
http://www.hydraulicsupermarket.com/technical.html


Yours for better hydraulics knowledge,

Brendan Casey
Author of 'Insider Secrets to Hydraulics'; and
'Preventing Hydraulic Failures'.

=======================================


If you no longer wish to receive the valuable guidance
provided by the 'Inside Hydraulics' newsletter
and associated mailings, point your browser to this page:
https://hydraulics.infusionsoft.com/opt?o=2&i=123560&m=771588&e=c893403f


==========


HydraulicSupermarket.com
1195 Hay St
PO Box 1029
West Perth, WA 6872
Australia
6 (189) 380-6659

Delivered By Infusionsoft

Selasa, 10 Agustus 2010

Air your 'Inside Hydraulics' newsletter is ready


August 10, 2010 

'Inside Hydraulics' Newsletter
http://www.hydraulicsupermarket.com


IN THIS ISSUE
1. Patience may be a virtue... but it's not always an asset
2. Filtration: can you have too much of a good thing?
3. How to deal with hydraulic connector leaks
4. Content for your web site or e-zine
5. Help us spread the word
6. Tell us what you think

1.

Patience may be a virtue... but it's not always an asset

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 99.9 percent of hydraulic systems out there, probably not.

Even for critical, servo-valve systems, filtration of 2-micron absolute is 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.

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



3.   How to deal with hydraulic connector leaks

The problem of leaking connectors has been around for as long as hydraulics itself. It is beyond annoying. It wastes oil. It poses a safety hazard. It can compromise machine reliability. It's a big problem. In the May 2010 Issue of Machinery Lubrication available here, I outline what can be done and explain why doing nothing is not an option.


4. Content for your web site or e-zine

Need some fresh content for your web site or e-zine? You now have permission to reprint these 'Inside Hydraulics' articles on your web site or in your e-zine, provided:

1. Each article is printed in its full form with no changes.

2. You send an e-mail to editor@hydraulicsupermarket.com to advise us where you'll be publishing them.

3. You include the following acknowledgement at the end of each article:
About the Author: Brendan Casey has more than 20 years experience in the maintenance, repair and overhaul of mobile and industrial hydraulic equipment. For more information on reducing the operating cost and increasing the uptime of your hydraulic equipment, visit his web site: http://www.HydraulicSupermarket.com


5. Help us spread the word

If you've found our 'Inside Hydraulics' newsletter interesting and informative, then chances are you have a colleague who would too. Help spread the word about 'Inside Hydraulics' by forwarding this issue to a colleague. If they share your interest in hydraulics, then they will surely appreciate being told about this newsletter.

New subscribers can get the newsletter by completing the form at http://www.insidersecretstohydraulics.com


6. Tell us what you think

We would love to hear what you think of this issue of our 'Inside Hydraulics' newsletter. And of course, if you have any suggestions for future issues, please send us those too.

Just e-mail the editor at: newslettersuggestions@hydraulicsupermarket.com

Copyright 2000-2010 by HydraulicSupermarket.com. All rights reserved.


To subscribe to this newsletter, go to:
http://www.insidersecretstohydraulics.com

This issue was sent to the following e-mail address:
abelkefa.tools@blogger.com

Kamis, 05 Agustus 2010

Air, what causes a cylinder to creep?

Hello again Air,

In your last hydraulic maintenance email, I exploded
the myth about pump suction strainers - they do more harm
than good. And installing them to 'protect' the pump is a
contradiction because they can actually destroy it.

Here's another big myth ...

Myth #2. Creep in a double-acting cylinder is caused by a
leaking piston seal.

A popular misbelief about hydraulic cylinders is that
if the piston seal is leaking, the cylinder can creep down.

Fact is, if the piston seal is completely removed from a
double-acting cylinder, the cylinder is completely filled
with oil and the ports are plugged, the cylinder will hold
its load indefinitely - unless the rod-seal leaks.

What happens under these conditions - due to the unequal
volume either side of the piston, is fluid pressure equalizes
and the cylinder becomes hydraulically locked. Once this occurs,
the only way the cylinder can move is if fluid escapes from
the cylinder via the rod seal or its ports.

If you grasp the theory at work here, you'll probably realize
there are a couple of exceptions. The first is a double-rod
cylinder - where volume is equal on both sides of the piston.

And the second is when a load is hanging on a double-acting
cylinder. In this arrangement, the volume of pressurized fluid
on the rod side can be accommodated on the piston side.
In this case a vacuum will develop on the piston side and
depending on the weight of the load, this may eventually
result in equilibrium that arrests further creep.

For more on these and many other hydraulics tips,
point your browser to:
http://www.hydraulicsupermarket.com/technical.html


Yours for better hydraulics knowledge,

Brendan Casey
Author of 'Insider Secrets to Hydraulics'; and
'Preventing Hydraulic Failures'.

=======================================


If you no longer wish to receive the valuable guidance
provided by the 'Inside Hydraulics' newsletter
and associated mailings, point your browser to this page:
https://hydraulics.infusionsoft.com/opt?o=2&i=123560&m=769858&e=c893403f


==========


HydraulicSupermarket.com
1195 Hay St
PO Box 1029
West Perth, WA 6872
Australia
6 (189) 380-6659

Delivered By Infusionsoft

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