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Vacuums and degassing questions and issues
Hey guys,
I have been running some experiments with vacuums for the purpose of degassing fluids and for building assemblies that are bathed in hydraulic fluids that require minimal gases within their assemblies.
When I draw a vacuum on a liquid (in this case, a special type of hydraulic fluid) I can see the fluid boil, which is obviously the small amounts of trapped air within the liquid.
However, after many minutes under a vacuum...the fluid keeps on producing bubbles.
In addition to this, I have found that when I introduce certain materials with the fluid (such as bare aluminum and steel) I get bubbles that come directly off of the materials...and for very very long periods of time. Basically so long that I never see an end even after running the stuff under a vacuum for many hours.
I then found this paper.
[ATTACH]1171[/ATTACH]
In this, it talks about various materials giving off gases when put under certain levels of a vacuum. All new to me.
So...I think what I'm looking for is some insight and input into what you guys think is going on here.
If I'm getting bubbles directly off of a piece of raw steel, is that from the Zinc in the steel? And if so, what is the gas? If I trapped this "gas" and then remove the vacuum, what do I have?
And...I guess more importantly, is degassing, for the purpose of removing trapped air within a liquid, something that you expect to get a near perfect result within a minute of two, or is it expected to have a more pure liquid within a vacuum for extended periods? In other words, should a good degass process be 5 minutes, or several hours?
Thanks for any and all input.