Refrigeration oils - boiling pressures
George Goble
>Some time ago I posted a similar question but received only partial responses. By partial, I mean partial. Half posts etc. The balance(s) of the posts are still swirling in the ether.
>
>Does anyone know the actual boiling pressures of refrigeration oils? I know Copeland has stated that mineral oils boil at approximately 250 microns. Is this figure accurate? How about POE's? Is there information available about the boiling pressures for these? Considering their affinity for moisture, specifiers are demanding, I believe, vacuums which are too low and may be detrimental to the integrity of the oil.
>
>Any ideas?
250 microns is about right for the mineral oils.. I am not sure about
PAG oils, but I have heard that PAG is much more volatile..
Deep vacuum will not screw up mineral oils, you can pump for
days, and only boil out a teaspoonfull or less, which contaminates
your vac pump oil, and this self limits the vac to 250 microns.
--ghg
Lorne Lowry
ml...@delphi.com
>Some time ago I posted a similar question but received only partial responses. By partial, I mean partial. Half posts etc. The balance(s) of the posts are still swirling in the ether.
>
>Does anyone know the actual boiling pressures of refrigeration oils? I know Copeland has stated that mineral oils boil at approximately 250 microns. Is this figure accurate? How about POE's? Is there information available about the boiling pressures
f >
I have an alternative refrigerant matrix published by tecumseh products co.
s general info on several mineral oils, POE's, and
alkylbenzene's. It also gives vapor pressure in psig at -10F, 45F,
and 130F. If you are interested in a faxed copy, email me with a
name and fax number. DISCLAIMER: this is general info ive picked
up along the way, and should be verifed using ASHRAE Fundamentals or
equivalent..
gsh...@cpieng.com
In Article<4cm45g$f...@news.magi.com>, <lo...@magi.com> writes:
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> From: Lorne Lowry <lo...@magi.com>
> Newsgroups: sci.engr.heat-vent-ac
> Subject: Refrigeration oils - boiling pressures
> Date: 6 Jan 1996 15:23:28 GMT
> Organization: Magi Data Consulting
> Lines: 5
> Message-ID: <4cm45g$f...@news.magi.com>
> NNTP-Posting-Host: magi04p31.magi.com
>
> Some time ago I posted a similar question but received only partial
responses. By partial, I mean partial. Half posts etc. The balance(s) of
the posts are still swirling in the ether.
>
> Does anyone know the actual boiling pressures of refrigeration oils? I know
Copeland has stated that mineral oils boil at approximately 250 microns. Is
this figure accurate? How about POE's? Is there information available about
specifiers are demanding, I believe, vacuums which are too low and may be
detrimental to the integrity of the oil.
>
> Any ideas?
The POEs are less volatile than most mineral oils. As example, during
processing (manufacture) the final vacuum drying step uses high vacumm at
temperatures up to 400 deg. F. The vapor pressure is so low at 100 def. F.
that it is essentially not measurable. We often measure vapor pressure at 400
deg. F. as low as .0001 mm hg. Generally, the higher the viscosity of the
POE, the lower the vapor pressure. Thus and ISO Viscosity Grade 68 has a
lower vapor pressure (less volatile) than an ISO VG 22. Also, most
manufactures use a small amount of inhibitor to prevent oxidation in handling.
In fact, POEs can be used as vacuum pump oils provided they contain inhibitors
A note to others who have responded: POE is polyol ester, PAG is
polyalkyleneglycol. POEs have much less affinity to moisture than PAGs
Glenn Short ASHRAE TC 3.4 (lubricants) Chairman