Oil Condition Testers

<...oil conductivity test instrument...>

Oils are generally a mixture of organic molecules and do not have a conductivity, which is a property reserved for ionic species usually in aqueous solution, and oil and water do not mix.

<...dielectric constant...> is not <...conductivity...>.

<...water micro-droplets, carbon specs, dust, etc....> would suggest there is a significant materials segregation problem that is overdue for a remedy. Maybe the equipment that is being oiled is being pushed beyond its economic lifespan, or deep maintenance is being postponed inordinately, in which case catastrophic failure and revenue damage is imminent.

Class II lubricating oils (heavy hydro-treated base oils) without additives measure in around less than 10 pS/m. With anti-corrosion additives (formerly were zinc dithiophosphate), whatever they may now be as zinc ones were unsafe in the environment apparently, the conductivity value may rise to 400-600 pS/m.

I have found at least one meter available on the market for said ASTM D2624 protocol.

I am really more interested in the grid capacitor test. It has to do with particles settling out of the oil.

ASTM Test Method D2624 is limited to fuels containing static dissipator additive.

Is this test method germane to Class II lube oils?

Link: Guide to ASTM Test Methods for the Analysis of Petroleum Products and Lubricants: 2nd Edition

Yes it is germane to testing lube oils.

http://www.machinerylubrication.com/Read/29407/oil-condition-monitoring

https://ac.els-cdn.com/S2212017314001625/1-s2.0-S2212017314001625-main.pdf?_tid=c5fabe1e-02a3-11e8-929c-00000aacb361&acdnat=1516976486_a3867dbfca8166395f18ea38df89be8b

The first link is about using EC (electrical conductivity) to test lube oils, the second includes a paragraph about using capacitive ( The dielectric constant (D.C.) is also known as relative permittivity) bridge testing to indirectly determine the D.C.

The grid capacitor test is not typically not or setup to be done online, but could be.

It requires the introduction of test oil between plates of a capacitor such that the bottom plate is actually a wire grid, and the test is under no flow condition, such that the particles in the oil settle to the grid, and affect the D.C. over the observation time of several minutes. This can give clues to water micro-droplet concentration, carbon particles from static-induced micro-sparks, etc. It is not typically viewed as a chip sensor like what would be on the oil system of a gas turbine.

I don't think this is quite what you want....but we gotta start someplace....

https://www.indiamart.com/shree-abirami-enggineering/transformer-oil-test-lab.html

That link is apparently for a full service laboratory offering an entire panel of available testing services, and not a bad idea at all for an organization to have contacts with.

We do already have oil analysis services, and our maintenance personnel are well-versed in grab sampling technique to ensure proper samples are recovered and sent periodically to the lab.

We want a "cheap" tester for on-site frequent use (if management will just approve it).

As to the grid capacitor I think I can make one, I do not see anything sophisticated about this at all, as long as all residues are easily cleaned away between tests.

I can see doing an inlay of copper wires in PE (polyethylene) or PTFE (polytetrafluoroethylene teflon) platen, machined to close tolerances with a lip or added gasket spacer of the same material to control spacing in the oil chamber. The upper platen can be the same thing, or a simple (very flat) piece of metal. Oil would be introduced in such a way that excess oil would be squeezed out when the top platen is closed. Capacitance bridge circuit then begins logging test results and continues for up to ten minute interval. Results would then be brought up and charted, or statistics such as the linear least squares fit or polynomial fit would be characterized. Dielectric constant changes also computed from the changes in this test capacitor. Test frequency could even be 60 Hz, as the limit for this type of test is a mere 104 Hz, since we want to be on the flat part of the curve. No high frequency is required as would be in solid dielectric testing.

Maybe something here you can use...

http://www.agarscientific.com/tem/grids-agar.html

I googled conductivity meters and got a lot of results for Hach, Rosemound, Extech, etc. I had started looking for a mhometer, but the industry calls them conductivity meters.

Any reason you couldn't make a parallel copper plate plunge type probe and put it on a megger?

That might work, since we already (obviously) in a power company have the megger.

There is about 8 order of magnitude more sensitivity (i.e.-less current) for a pS/m type conductivity instrument for oil, than a μS/cm type instrument for water conductivity.

Thanks for the idea. The grid capacitor thing, I can take care of with some Arduino wizardry, I suspect.

How are things in the far north (Oregon)?

Wet.

Wet megger test, is that what you are referring to? Yeah, this can be a problem is really wet oil is tried.

Nope. Wet. It's raining outside.

Oh, we are "wet" here also, since today was the first in about 100-120 days I have been able feel, smell the moisture in the air, and we had enough precipitation to dampen the sidewalks in a couple of places from dew fall. That is how things are here, either feast or famine.

Since the Christ child (El Nino) is over, I would not expect much this year, and also at solar minimum. I can be wrong also.

I don't know anything about this stuff. Is what you want the kind of stuff provided by Parker Hannifin. ?

I looked at some of their stuff, and did not find oil conductivity tester, but other kit.

Not quite sure which paper you were reading, but there are many out there that describe the use of capacitor based sensors. Similar to DGA (dissolved Gas Analysis) of transformer oil, the "gotcha" is that you need a series of baseline data points to compare with the data as the oil ages.

You might find some more information on capacitor-based sensors in some of the papers discussing oil health condition monitoring.