Sauron
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How to Calculate Pressure for Gas over Liquid in Cylinder?
and also Cylinder Material Decisions for Lecture Bottles
I am rather bewildered trying to choose between the following:
Aldrich stainless steel lecture bottle
Aldrich carbon steel lecture bottle
Swagelok stainless steel sample cylinder
All of the above are rated 1800 psi, while Swagelok has additionally models with thicker wall rated 5000 ssi
Aldrich Sure-Pac mild steel syclinders are only 240 psi.
I am interested in getting advice on which is best choice.
Swagelok cylinders are double ended, so bottom would be closed with a plug (1/4 NPT).
The gases of interest are Cl2, SO2, NH3 primarily, generated and dried then condensed into florence pattern Dewars for transfer to the cylinders which
will then be closed with stainless steel diaphragm valves.
Sic gorgeamus a los subjectatus nunc.
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not_important
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Wouldn't it be the pressure at which the b.p. equals ambient? SO2 around 4 atmospheres, Cl2 ~7 or 8, NH3 close to 10; in all cases 240 psi would
work, except possibly in the torrid climate you live in.
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Sauron
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In that case any of the SS vessels will be fine, they variously are rated at 1000, 1400, 1800 or 5000 psi. The 240 psi stuff is mild steel and I am
concerned about corrosion.
Anyone see any advantage 304L vs 316 L for the reagents mentioned?
Swagelok has both.
Aldrich as usual is overpriced for everything, Swagelok is a better deal. A 1 liter Swagelok cylinder costs less than a 440 ml Aldrich SS lecture
bottle and is rated identically, takes same fittings etc.
Also Swagelok has local stock, while Aldrich is a pay in advance and hurry up & wait for delivery.
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gsd
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| Quote: | Originally posted by Sauron
How to Calculate Pressure for Gas over Liquid in Cylinder?
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Do you really mean "Gas" or is it "Vapour"?
Vapour is something which can be liquified by a reducing the temperature at constant pressure OR by increasing pressure at constant temperature. In
case of a gas you have to do both, i.e. decrease temperature and increase pressure - to liquify it.
For all the three compound you have mentioned, the vapour pressure data is easily available, even Antoine's equation gives fairly accurate T vs P
relationship.
gsd
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Sauron
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Do you really mean to be a pedant?
Your remarks as as usual singularly unhelpful.
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gsd
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I don't know.
If pointing out the fundamental difference between two scientific terms - which are very often loosely and interchangiably used - to a scientist (
hopefully I suppose) is being a pedant, then so be it.
If I try to tell somebody how/where to get very easily available information, and the person is insisting only on a direct spoon-feed, then I can't
help it.
gsd
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Sauron
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Pointing out the obvious to someone who has been doing this for 45 years is pedantry. You were not trying to be helpful, you were splitting hairs. The
terms are used interchangeably, and no problem, unless and until the situation calls for more precision. This was not such an occasion. You were just
being a smartass, which is usually the case with you lately. Get lost.
Furthermore, I have been spending 12 hours a day for a month downloading, editing and uploading a journal to MadHatter and 4shaRED FOR THE BENEFIT OF
THE MEMBERS AS WELL AS MYSELF. sO WHEN i ASK FOR A LITTLE TECHNICAL ADVICE IN THE MIDST OF THAT, YOU WANT TO CALL THAT ASKING FOR SPOONFEEDING?
What have you done for the forum lately?
[Edited on 18-12-2008 by Sauron]
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gsd
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tut. tut...
When there is no logical argument left........Start abusingl Left right and centre. 
Which is usually the case with you lately. But don't get lost. I am a reasonably liberal person. Keep abusing if it amuses you.
gsd
PS: Re what I have done for the forum, I am not answerable to you.
And I think it is hopeless to expect you to remember what I have done for YOU.
gsd
[Edited on 17-12-2008 by gsd]
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Sauron
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You are right. I don't dwell on minutiae, and that is what you have ever done for me, or for that matter, for the forum.
DO get lost.
Sic gorgeamus a los subjectatus nunc.
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