Hi,I attended a presentation last Friday by a well known filtration corporation. The CLS (certified lubrication specialist) claims that anti-foamants can be filtered out because they are in the 4 micron range.Is this just some B.S. or is this possible? We are experiencing a great amount of varnish build up and the recommendation is to use electrostatic cleaners or the CC Jensen type filters. The oil we are having problems with is PM 220. Any suggestions? Brett

Yes, this is true. You can filter out foaming additives through both conventional filtration and electrostatic methods. If the oil is clean and free of submicron contamination, you will prevent and remove varnish,as well as prevent foaming. Of the two choices, only electrostatic systems give you the level of cleanliness required to prevent foaming and give long-term control of varnish. Call me for more information.

Recent research indicates air release time is a function of, and varies directly with varnish potential. If you have a varnish problem, you probably also have a foaming problem.

Ray, I have been leaning toward electrostatic cleaners and have done some research regarding varnish. My observation over the years with these oil systems,(PM220)when we went from 20 micron filters to 5 micron filters the varnish rapidly appeared.Now it causes stuck roto-gears,(Esko)and Safematic flow site glasses.I am not aware of any foaming,however a recent oil analysis showed a lack of proper additive ranges.If you would send me info on ISOPur cleaners to my email address(brett.lukens@npiusa.com)Thanks, Brett

A few years back we installed our machines on several large turbines at a power plant in Asia. The engineers at the plant wanted to make sure they did everything to resolve their oil purity problems and eliminate varnish as quickly as possible, so they reduced the pore size of the full flow filters to a very low value, 1-3 micron range. As engineers we all know bigger, in this case smaller, is better. If 10 micron works ok 1 micron will work really good! We had misgivings and told them this may not be such a good idea.

After several months of operating our machines on their turbine lube oil systems, they found varnish was still increasing. We told them to go back to the manufacturer's recommended filter size on the full flow filters. After they changed filters, we were able to catch up to the varnish ingress and start to clean their systems.

What happened? We sent their filters out for analysis at Focus labs in Thailand. Andy Sitton found what we suspected, signs of intense static discharge in the filters. The amount of static produced in oil filters varies proportionally with oil flow rate and inversely with pore size. Smaller filter pores produce a lot more static discharge in high flow situations. Static discharge causes oil breakdown that is characterized by increased varnish. I think, this may have happened in your situation.

You should go back to the original filter size. You may have to flush the system and change oil, and/or purchase or rent an electrostatic filter (preferably one of my BCA systems) to get the oil and system clean again. Overall quality of the oil and its additives must be determined to make the correct decision as to which of these choices is best.

brettl3,

1. What you heard on this presentation really is BS, because solid antifoam particles are less than 1 micron in size (more like up to 10x smaller than what is stated by this CLS).

2. Under certain conditions (e.g. low temp, heavy contaminated oil) antifoamant particles could agglomerate to the stated sizes and get filtered out, but this does no harm because as such they have been totally ineffective anyway.

3. If you don't have foaming and air entrainment problems then your problem is not antifoamants (and them possible being filtered out) because they obviously perform as intended.

4. How you know you have a varnish buildup problem, and not problem caused by oil contamination from other sources?

5. Knowing the typical sizes of varnish particles, a properly sized low-flow filters with a relatively small sized (e.g. 3-micron) dept-type media or electrostatic filters are effective in capturing varnish. Low-flow is also "key" in the performance of electrostatic filters (otherwise small varnish particles would be flushed from filter back into the oil).

6. It is true that high oil flow through small size filters can generate static electricity and causing sparks which produce varnish. However, no one in his/hers right mind would try to capture small varnish particles at high flows, and on in-line basis.

7. If you have moisture present in oil then the efficiency of electrostatic filters is poor, unless it has a cellulose-type scrubber pre-filter. In that case you would be better served with the absorbent type media (e.g. cellulose). I am saying this based on our experience gained thru a field test, where both systems; off-line low-flow depth-type 3-micron filters and an electrostatic filter with added cellulose scrubber, were similarly effective in controlling varnish. However, we decided to go with “classical” off-line systems, because of lower cost of the units and their long term maintenance.

Bypass filtration post
Here is a link to the post showing an experiment we ran on an injection molding machine. We basically put our mixing and charging unit, CMU, in front of an existing depth filtration unit. This was a low flow application where they had been using depth filtration for years, yet the oil was full of varnish. Simply adding an agglomeration unit in front of the existing filter cleaned the oil far beyond the capability of standard filtration.

I cannot seem to link directly to the post, so just look at the bottom of the page.

This message has been edited. Last edited by: Ray Gomes,

Brett,
If you decide to flush out the varnish from your system or perform online varnish removal, please contact me as we have experience in performing this service.
eric@rccnow.com

Hi Ray

Did you mean to mix up air release and foam? They are different measurements and it is possible to have poor air release and acceptable foam results and vice versa. Their impact on system performance is very different as well. Regardless, what is your recent research about air release and varnish? These research findings are different than what I've seen in the field. Is this research published?

Thanks,

Greg

PS - Good write-up on foam inhibitors JM!

quote:

Originally posted by Ray Gomes:
Yes, this is true. You can filter out foaming additives through both conventional filtration and electrostatic methods. If the oil is clean and free of submicron contamination, you will prevent and remove varnish,as well as prevent foaming. Of the two choices, only electrostatic systems give you the level of cleanliness required to prevent foaming and give long-term control of varnish. Call me for more information.

Recent research indicates air release time is a function of, and varies directly with varnish potential. If you have a varnish problem, you probably also have a foaming problem.

The research is being done by a well known lab. I hesitate to give more information, becaues I don't want to mess up a potential paper by quoting the research at this time.

I have heard this story going around and I have to agree with a previous post by John Micetic. As a plant engineer at a major utility for over 20 years, I can tell you from my experience that this is total BS. We ran very aggressive filtration levels on all of our turbine oil, fan, and boiler feed pump reservoirs (4 units in total), 1 um, now Beta (2.5)c under the latest ISO standards and we did not see any evidence of additive removal. What did strip out the additives over time was excessive ingression of moisture and contamination, which would be expected. About 20 years ago we were experiencing excessive ingression levels of water though the steam seals on two of our older GE machines. The station purchased and installed coalescing units from a major vender, which we were never able to get working. We continued to see issues with oil foaming, bacterial growth (on the coalescing elements themselves), poor particle counts and a rapid reduction in the ability of the oil to separate water. After replacing all of our coalescing units with vacuum dehydrator technology, we were able to not only clean up and dry our oil out, but we also saw that our oil performance parameters remained consistent throughout the next ten years that these machines were in use. I have seen a number of different vendors come in and try to muddy the waters, but in my opinion, you should be using vacuum dehydration technology where it makes economic sense to do so, and use a high quality synthetic (grounded) element, and I believe that the majority of your issues will resolve themselves.

Certainly filtration is important, however what causes varnish to form? Heat is the most common factor. The heat causes the lubricant to break down faster and attacks the additives. How about looking at a better quality fluid before investing extra money in additional filter systems that you may not need. How about an experiment. Get two products VarniClean to clean out the system and remove the varnish build-up and the appropiate grade of fluid (for your application)that contains VarniShield to prevent varnish from forming in the first place.