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Unusual Hyd Pump Wear

01/19/2017 1:10 PM

Hello everyone, no time no see; health issues. Anyway, I'm consulting with a company regarding some hydraulic pumps and issues with these. These are vane pumps, single and double pumps, and on the smaller replaceable pump cartridge in the double pump, and on the single pumps which use a small displacement cartridge, I am seeing some unusual wear, in particular on the bronze plated "flex plates" installed between the cam ring and support plates. (1) It appears the vanes in the cartridge are literally milling out the bronze stock as it is in operation. I have seen a large number with this wear, and two were worn down to the steel back. Note, it is NOT a burn, but literally material worn away. (2) This is limited to the intake or suction (low pressure) side flex plate of the pump. The flex plate (they are the same plates, by the way) on the discharge (high pressure) side of the pump is not seeing this type of wear. There is some wear of the type I have noted in the past on this discharge side plate, but not as with the suction side plate. I have found these are being used in Canada and the U.S. Pacific Northwest; 15W hyd oil in use. The application is a boom truck with an auger. I'm told these are supposed to be balanced hydraulically with no axial loads/forces, but it appears some type of axial force is occurring. I've had parts measured, but nothing appears to be out of spec. Thank you.

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#1

Re: Unusual Hyd Pump Wear

01/19/2017 2:31 PM

Cavitation? (Just a WAG.)

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#3
In reply to #1

Re: Unusual Hyd Pump Wear

01/19/2017 10:26 PM

Same here (cavitation)

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#5
In reply to #3

Re: Unusual Hyd Pump Wear

01/20/2017 1:12 AM

If it is cavitation, clean or change any filters before - make sure no obstruction on inlet - elevate reserve tank if possible - port & polish intake ports & elbows - FWIW -

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#6
In reply to #1

Re: Unusual Hyd Pump Wear

01/20/2017 8:41 AM

Just what is a WAG?

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#7
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Re: Unusual Hyd Pump Wear

01/20/2017 10:47 AM

Wild @ss Guess

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#9
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Re: Unusual Hyd Pump Wear

01/20/2017 12:39 PM

Well some times 40 years of experience can produce a quick and accurate answer. The indication was that much was checked and this was a reoccurring issue. Many miss the cavitation unless the audible sound is present. That is why on many of my posts I suggest the use of ultra sound. If they had listened to this pump with an ultra sound device and were properly trained the tell tail popping sound of bubbles would probably be heard. Others mentioned cleaning the intake filters which are a prime cause of this cavitation along with leaks that allow air into the system.

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#12
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Re: Unusual Hyd Pump Wear

01/25/2017 8:52 AM

Ultra sonic checking is an excellent idea. I will see if we can arrange an extended field visit to perform that. I will add (updated information) we are seeing failures (some, not a high volume but some) of these during pre-delivery inspection, and others as long as 4 to 6 months out, up to a year in some cases. Note the wear may NOT be constant to the length of time; we have see long term cases with moderate wear and short term cases with significant wear of the plate. I mention the pre-delivery inspection because the manufacturer will be installing new systems including filtration, which I hope one could assume are clean, but then, one never knows.

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#15
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Re: Unusual Hyd Pump Wear

01/25/2017 10:27 AM

It may be possible to detect cavitation by adding a Fourier analyzer app to your phone - hold it near a known good circuit, then near the suspect circuit - you may / should see a sig. difference in the frequencies and amplitudes.

I use one of these apps to find leaks in my compressed air lines & equipment - works very well.

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#16
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Re: Unusual Hyd Pump Wear

01/25/2017 2:38 PM

Interesting.

Share links?

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#20
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Re: Unusual Hyd Pump Wear

01/26/2017 1:29 PM

If you type 'Fourier Analyzer' into a smart phones app search, you should get a number of suitable apps, both free and paid.

Then if you open the app near a 'known good' ('quietish') hydraulic circuit, it might look something like this.

But if the circuit has cavitation, etc, it might look something like this.

The F. Analyzer plots a sound map - x direction is the frequency, y is the amplitude, or the power of the noise at that frequency.

Have not used mine for hydraulics , let me know if it works. Good luck.

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#21
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Re: Unusual Hyd Pump Wear

01/26/2017 2:14 PM

I am interested in recording sounds made by the various bubblings that take place in a steel electrolysis vessel where the vessel itself if the cathode.

Is that a price in bitcoin in the upper right? hmmm...

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#22
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Re: Unusual Hyd Pump Wear

01/27/2017 2:31 AM

You might need to use a mic you can attached to the vessel - or even one you can put in the vessel - but not sure how long it would last!

http://int.search.myway.com/search/GGmain.jhtml?p2=%5EBSB%5Exdm071%5ES18313%5Eth&ptb=8813C8F0-B3A5-4E4E-A118-9A7564C61FFE&n=782b4356&ind=&tpr=tbsb&trs=wtt&cn=th&ln=en&si=COqZnvyR1c8CFUUXaAodo78MGg&brwsid=451f7ec8-2cf0-40da-bbaf-c3e6973f59a6&searchfor=hydrophone&st=bar

Apps are there for smart phones to record, even free with the OS.

That price is in Baht - ~ 35 / 1 - so 179 baht is just under 6 US.

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#23
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Re: Unusual Hyd Pump Wear

01/27/2017 11:24 AM

We can hear the sounds outside the vessel, even outside the foam insulation calorimetry enclosure - actually impressive pinging sounds at times. I suspect Arduino would love this, but only if the sounds could be superimposed to be a non-negative voltage (or convert to digital with a shield board), then log it, but my God, listening to 100 hours of that for a tell-tale "pop-ping" sound of a cavitation bubble, or localized hot spot bubble would be mind numbing.

I appreciate the link, my friend.

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#11
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Re: Unusual Hyd Pump Wear

01/25/2017 8:46 AM

I am considering some type of cavitation or perhaps aeration issue. I am thinking some type of hydrostatic imbalance is involved, perhaps with the unique conditions of the special oil, temperatures and operating conditions.

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#2

Re: Unusual Hyd Pump Wear

01/19/2017 4:16 PM

Have you looked at particle analysis on any of the oil where this wear is showing up?

The thing that I find vexing is the isolation to the low pressure side of the pump, not the discharge side.

Maybe our buddy is right about cavitation. It is possible, especially if the fluid is contaminated with high vapor pressure product, or is wet, etc. Do the pumps become louder on long-term operation (say an hour or two after starting up)?

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#4

Re: Unusual Hyd Pump Wear

01/20/2017 12:03 AM

A few questions

What pump model is it?

What pto percentage are they using?

What is the max engine rpm setting?

Over what time period does this wear happen?

Can you share a picture of the damage?

As for cavitation that will show up on the vanes more than anything. It first shows as pitting but progresses to something that looks somewhat like disolving. Do these pumps have that kind of damage?

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#14
In reply to #4

Re: Unusual Hyd Pump Wear

01/25/2017 9:02 AM

Vickers 2025 double pump (failure in the 20 cartridge, the 25 is not impacted), standard performance, and the Vickers 25 single pump, high performance model.

We are waiting on PTO and rpm information. The time frame has been anywhere from an hour to a year on the extreme ends. It appears to be averaging 3 to 6 months. A picture of an extremely worn plate has been attached to another post.

The vanes illustrate scratching and mild discoloration, but not pitting or metal removal/transfer/dissolving.

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#17
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Re: Unusual Hyd Pump Wear

01/25/2017 11:29 PM

Okay. I'm very familiar with those pumps though in my case they are all new. Digger derricks for the double pumps and aerial buckets for the singles.

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#8

Re: Unusual Hyd Pump Wear

01/20/2017 11:19 AM

If it's not cavitation or excessive moisture contamination related, running the fluid way too hot or having too thin of fluid for the working temperatures and pressures can cause rapid pump wear issues.

The target temperature range I have always shot for in a hydraulic system is 160 - 200F for at least 50% of the operating time in normal operation.

Much below 160F and the fluid doesn't get warm enough to drive out any moisture it may collect and much over 200F most lighter grade general purpose hydraulic fluids will start to lose too much viscosity and lubricating characteristics when subjected to high loading conditions.

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#13
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Re: Unusual Hyd Pump Wear

01/25/2017 8:56 AM

Yes, I am concerned about the temperature extremes. We have been informed these are being run at both extremely cold and hot temps, and with that special oil, I have a major concern it is losing adequate viscosity at hotter temperatures. Conversely, we have inquired if the manufacturer is supplying auxiliary heating to warm the oil at very low temps, and I have not yet received an acceptable answer.

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#18
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Re: Unusual Hyd Pump Wear

01/25/2017 11:33 PM

A tank heater is a good idea in the winter months. In my experience most major fleets spec this as standard equipment.

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#10

Re: Unusual Hyd Pump Wear

01/25/2017 8:43 AM

Update: I have seen some additional pumps with the indicated wear. In addition, I have determined that the wear pattern moves with relation to how the pump is assembled for operational rotation; that is, there are "forward" and "reverse" rotation pumps. The cam ring/vanes/flex plates are inverted to change the rotation. The wear stays with the intake or suction side with the component inversion. Also, the vendor is using a special oil by Kendall ("Glacial Blue") in this application (Canada/US Pacific NW). We are obtaining a supply of this oil to attempt to duplicate the operating conditions. A photo is attached illustrating the most extreme condition; we are seeing this pattern of wear with varying degrees of depth of the milling of the bronze alloy.

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#19
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Re: Unusual Hyd Pump Wear

01/26/2017 12:20 AM

Glacial blue is a good low temp oil. We have one major fleet client that used it.

That wear looks to be from the vanes themselves. I have heard of something like this that had to do with a clogged suction filter or strainer, I don't recall exactly which.

I'll run this picture past some of service guys to see what they say.

Also if you haven't found it yet Parker has a great trouble shooting guide for vane pumps.

https://www.google.ca/url?sa=t&source=web&rct=j&url=https://www.parker.com/literature/Vane_Pump/PDF%2520Literature/SERVICE/CatalogueTroubleshooting-HY29-0022-UK.pdf&ved=0ahUKEwiiq9PyhN_RAhVP_WMKHRK9BqAQFggcMAE&usg=AFQjCNGrlV7rj6keOZOSA6UBLiDxtlq2vQ&sig2=a72kwEYGyNEwWgQtXvTclw

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#24

Re: Unusual Hyd Pump Wear

02/21/2017 9:46 AM

Update: we have confirmed that a 15W oil is in use with these pumps. Also, we have some more equipment configuration information: Engine RPM is 1100, with a 120% PTO ratio for a pump RPM of 1320. Oil temperature is running at 145 deg. F. A concern is the use of a 1 1/2" inlet hose that is 17 ft. long. The engineer I am working with has a concern about sufficient fluid flow. Also, a 50 gallon tank is being used.

So, the next step will be an attempt to duplicate the operating conditions. I have worked with the company to configure a test stand to run the 15W oil at elevated temperatures (145 deg F as noted), and across a range of temps. If the failure is not noted, I will work to reconfigure the test stand to (as closely as possible) replicate the inlet hose setup (17 ft long 1 1/2" hose).

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