Water Content In Oil. Units Equivalences.

Dear Kramarat,

many thanks for your answer.

It is near but not what I look for.

I do have "% of water saturation in oil" at hand.

It is not the same than absolute % of water content.

And I do need to translate it into ppm or absolute %.

Some hint about it?

You lost me.

But, if I was charged with finding the exact amount of water in a particular sample of oil, I would set up a small distillery, heat the oil until the water vaporized, send it to a cooling container, and measure the amount of water compared to the total initial sample. This could be measured by weight or volume. I would think that you could obtain very accurate measurements.

This entire site looks like a good resource and includes methods that I'm not familiar with.

http://www.machinerylubrication.com/Read/2149/dry-oil

The more details you include about what you are doing, the better the chances of getting an answer. Somebody here will know.

I think you may find the answer to your question here:

http://www.machinerylubrication.com/Read/200/water-saturation-screening-oil

Dear all,

The preliminaries are:

Barrels of oil for hydraulic circuit were filtered and cleaned to NAS 6 level, getting them ready to fill the circuit once this was flushed.

These barrels were stored for some time and, being suspicious about the storage conditions, I requested the oil to be checked before marking it as "ready to go".

Now, I went trough the articles you indicated earlier, and they state very clearly that the measurement of water saturation in the oil is a more reliable method to stablish the amount of water that certain oil, at certain specific conditions, can contain safely.

I do have several values of "% water saturation" given by a HYDAC oil analiser,

With the oil type (Shell Tellus VG 68) , being the pressure atmospheric during the measurements , there should be some way to convert this value in ppm or simple %.

More in the line of the results that would be obtained in the distillery that Kramarat suggest (and althought appealing, I do have the means to do that, unfortunately).

Maybe they can not be converted, and I am hitting my head with a wall??

Some idea??

In any case thanks for the time and the attention,

Salu2

Abel

The topic is new for me but it is drawing interest. It seems from the analyser results that it is giving relative content of water in percentage with respect to maximum water at saturation at those test conditions.

Maximum saturation content of water at the test condition shall be given by manufacturer, i hope.

What does the manual say?

What does 46.6 mean? If it's the percentage of water saturation in the oil, no conversion in the world is going to make the oil usable.

What you are attempting to do is akin to expressing millimeters as parts per kilometer/percentage of kilometer, rather than just using them as the more accurate units of measurement that they are.

You hit the nail.

Now that I understand the difference and the principle, I requested to the supplier of the equipment his standards in the "new" units.

Actual values are ranging 30% / 50ºC, and going down.

I will install a water oil filter on each circuit after the initial filling, and request the customer to use higroscopic breathers in the reservoirs. A must here, really.

I guess this particular measurement is new to many of us, but assuming that what you are trying to determine is the relationship between percent saturation and ppm,you must determine how many ppm is equal to 100% saturation under specified conditions (probably temperature and pressure). You should then be able to simply scale to the number you are looking for. For example, if saturation at the specified conditions is 8800 ppm and your measurement reads .60 saturation, the water content is .6 X 8800 = 5280 ppm.

You are almost correct, but made a common error. Air doesn't "hold" water. Water saturation is independent of what gas the water vapor happens to be mixed with, or whether it is even mixed with another gas. The same rules apply in a vacuum. It is the partial pressure of water vapor alone that is the determining factor. I believe meteorologists have propagated the myth of air "holding" water.

OK. You are correct. I didn't want to get into a deep technical explanation here, so I used the colloquial language that most are used to. The intent was to explain the issue in understandable terms. It wasn't really a "myth"-take.

Dear all,

I got it, finally.

With your detailed and kind help, and the necessary dosis of personal effort, switched to the new units. Moving forward instead of backward.

Many thanks to you all.

Abel