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Oil boiling point at vacuum

  1. Mar 22, 2014 #1
    What may be the boiling point (temperature) of a refrigeration POE oil at, let's say, 500 microns absolute pressure ?
  2. jcsd
  3. Mar 22, 2014 #2


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    Your question is unclear. 500 microns of what? Water? Mercury?

    In any event, this information would probably be found on a material property sheet from the manufacturer.
  4. Mar 23, 2014 #3
    Millitorrs are generally called "microns". It is assumed among refrigeration engineers that during vacuumation processes the oils in systems worked upon, themselves, do not boil - no matter how high vacuum would be achieved. I am in doubt.
    Last edited: Mar 23, 2014
  5. Mar 23, 2014 #4


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    Every liquid has a vapor pressure ... if your vacuum goes below that, your oil will spread through the vacuum.

    Every electron microscope engineer knows this.

    Of course the vapor pressure is also sensitive to temperature; you would need the phase diagram to cover all of the pressure-temperature points.

    Here is a discussion of your topic in a refrigeration engineer forum:

    PS: in the sciences we call a millitorr a millitorr ... your use of "microns" refers to "microns of Hg". I'm sure it is useful in your engineering jargon as a short way of saying what you mean, but it is certainly not a common expression.
  6. Mar 23, 2014 #5
    I have already read this thread, thank you. (but it did not answer my question)
  7. Mar 23, 2014 #6


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    Why do you think we would know the answer? It depends upon specific, detailed knowledge of the oil and its phase diagram.

    Thus you should be searching for technical information on your POE oil; for example, the manufacturer's website.
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