View Full Version : Oil parameters
13-08-2005, 03:58 PM
Can anyone please tell me where to find data about oil parameters. I have sent refrigeration oil from troublesome sites for testing, but I have not been able to find detailed info about the upper and lower limits of the various tests that are done on each sample (eg: iron content, copper content, moitsure, particle count etc). Please help!
16-08-2005, 02:25 AM
Have you tried to obtain the oil specifications from the oil supplier? This would be your baseline for the test samples. Clean, fresh oil is the best of course. Any deviation from that implies contamination or lubricant wear. The compressor manufacturer may be able to provide the maximum values. The usually have recommendations for oil quality.
The filters/screens they use are another indication of their filtration requirments. The pickup screens for the oil pump will provide some basic information. (Mesh size as an example). They should also be able to tell you the filter ratings.
What type of information is the test lab supplying with the test report?
At a minimum they should be providing a measurement of the:
1) Viscosity at a specified temperature
2) Water content & type of water test used
3) Total Acid number
4) Particle count across a wide range of particles sizes (5 micron to 40 micron, in 5 micron increments)
5) ISO code
6) Antioxidant level
7) Wear metal content (Silver, Aluminum, copper, steel, tin, etc.)
8) Contaminant and or Additive metals (Silicone, Zinc, Magnesium, Molybendeum, etc)
I have used the oil analysis programs for trending wear on the compressors and useful oil life remaining. This is also useful information that can be incorporated with the oil filters used. Some of the better oil filters have ratings (absolute or nominal) for the particle size they will hold.
Nominal ratings are similar to a range of particle sizes. It is the average particle size the filter will restrict.
Absolute ratings are just that. If the filter is rated at 10 micron particle size, then this is the maximum particle size that will pass through the filter.
Better filtration of course means higher quality oil for lubrication. There may be some limit to what you can specify. I have seen people specifiy a 10 micron filter on an existing system (more dirt potential). The filters clog up very quickly as they try to filter the oil. This requires very frequent filter changes and is usually stopped after several weeks due to the expense and headaches it presents. Just a word of caution since I have run into this before in numerous cases.
This is an area where a partial implementation is required. Use better filter than what you have at first. After some time, use an even better filter until the time between filter changes starts to become long. Then switch to an even better filter. Small steps is the recommended method.
If you need additional information, please advise. I hope this helps you.
16-08-2005, 02:42 AM
I just found some additional information for you.
Try this wesite.
This is a South African company you should be able to work with. They know lubrication!:D
I have used them here in the USA and have had excellent results working with them. They are a major supplier for the industrial refrigeration market here in the US.
If they cannot help you, I would not know who to recommend for the job.
16-08-2005, 10:43 AM
Results aren't much good unless you know what they mean! I have some info but it's a bit long-winded and on a bit of paper at the moment. If the company Iceman recommends can't help you out then drop me a line. Any lab worth its salt should have told you what the various levels etc. mean. There are three parts to it really...
Tests vs. OEM spec like viscosity to see if the oil is in reasonable condition or has degraded. You should tell the lab the grade of oil you're sending them so they can compare.
Snapshot results which will tell you if there is an immediate problem, e.g. high iron content
Trended results - mainly for wear metals, if you see sudden changes then you know something is happening. Different systems have different levels of metals etc. swimming around in them, a snapshot only gives you so much info.
If you are having real problems then also think about asking for ferrography, which is microscopic examination of wear particles either in the oil or on the oil filter, which will tell you if it's sliding wear, rotary cutting, etc. Not all suppliers will be able to offer it though.
16-08-2005, 08:39 PM
Hello US Iceman and Johnny Rod, Thanks a mil. I've only been using this site since Friday last week - it's amazing! Funny what you can find when you know who to ask!! I've been trawling the net for weeks trying to get some answers (I only stumbled onto this site by mistake!). Some of what you guys have said, is basically what my oil analysis company has been saying - but since they have NO refrigeration experience, I assumed that these parameters must exist SOMEWHERE. It's ironic that someone halfway around the globe can find a source in your own back yard! - I will try CPI at first light tomorrow. Can someone tell me how to post links to websites in the thread - then I will post the more useful oil-related sites I have found so far.
US Iceman, are you refering to an in-line filter in the oil return line between the oil-sep and the oil reservoir/suction line?
16-08-2005, 09:33 PM
Glad to help you out. I suspect the information Johnny Rod is talking about is similar to some of the information I have. Lot's of paper. The test he mentioned should be very helpful also. I had not heard of it before.
I did a lot of work with CPI and Howden for ammonia, propane, CO2, R-22 and other mixed gas compression projects. If the guy in South Africa does not know the answers (which I doubt), the US office can find them for you.
Copying the links is straightforward. When you have the web address in your broswer window at the top of the page; highlight the entire address. A Left click of the mouse should do it.
Next use a keyboard shortcut. Press the Control Key and the C button while holding the the control key down. "Control +C"
This copies the address to the built-in Windows notepad.
When you want to paste it in the reply window, left click in the reply window and press the control key and the V button while holdin gthe control key down. "Control+V"
Control+C copies the highlighted text
Control+V pastes the highlighted text
(old software programmers trick):D
You can do the same thing with the right mouse button using the pop-up menus.
The oil filter location you describe is one area. On large screw compressors you will have either a single filter or a duplex filter (two filter housings). These filter the injection oil for the compressors.
I have also seen some systems that use an oil recovery system to reclaim oil from the system, filter and clean the oil, and then re-supply the oil back to the compressors.
In any case, clean oil with the right viscosity makes happy compressors! The oil analysis programs are worth the trouble once you get a good test lab and use the results.
Best of Luck,
08-10-2005, 12:06 PM
Hello US Iceman,
Sorry for the delyed response. As promised here is some of the more useful oil info I came accross (so far).
08-10-2005, 04:46 PM
Have the people from CPI been able to help you with the information you were looking for?
From my experience, the use of oil analysis provides a better understanding of the system condition when the reports are tracked over a period of time.
Let me know how you make out with this.
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