mr.crow
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Pyrex media bottles under vacuum
I have a bunch of 250mL Pyrex media bottles and am wondering if its safe to pull a vacuum on them.
Instead of building a vacuum chamber I could just attach a hose barb to the cap and vacuum it in place. This is to get rid of solvent residue
Double, double toil and trouble; Fire burn, and caldron bubble
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peach
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| Quote: | Are DURAN laboratory bottles suitable for working under pressure and vacuum?
In general, DURAN® laboratory bottles are not designed for pressure and vacuum applications.For pressure applications using laboratory bottles, the
DURAN® pressure plus bottle should be used. This is pressure resistant from -1 bar to +1.5 bar due to a modified geometry and increased wall
thickness.The plastic coating of laboratory bottles (DURAN® protect) has no influence on pressure resistance, these products are not designed for use
under pressure |
This is from the Schott FAQ, which is worth having a read of for the other capacities.
For example, the FAQ mentions that the glass is suitable for up to 500C and down to -196C, but notes how the glass can be fractured by heating and
cooling due to the none uniform geometry of the bottles.
I have witnessed this in person with two of their 10l bottles. It definitely does happen, despite it being borosilicate.
[Edited on 2-1-2012 by peach]
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phlogiston
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Although it is good practice to slightly unscrew the cap before autoclaving them, some people don't and they do withstand the pressure of the
autoclave (water at 120 deg C... which if I am not mistaking corresponds to a vapour pressure of about 1.5 bar).
I did however, also I crack several of them upon trying to cool them down too quickly by immersion in cold water.
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mr.crow
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Oh no, you broke your 10L bottle 
Sort of what I expected. It probably will work but not officially
A media bottle would also make a good water trap for water aspirators. Just glue two hose barbs in the lid.
Double, double toil and trouble; Fire burn, and caldron bubble
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peach
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| Quote: | | A media bottle would also make a good water trap for water aspirators. Just glue two hose barbs in the lid. |
There are adaptors that'll fit the GL threads on bottles, but they're somewhat expensive. The ones in the photos below go on 45 sized bottles and have
a B24 taper cut into the PTFE insert. I think they were $75 or so each.
It'd work with hose barbs, but you might be best getting some stainless air line ones (the kind that go on nail guns to make a quick coupling) with
screw threads on one end. Then you can drill a neat hole and screw them in with some epoxy or silicone on the threads.
The bottles breaking under vacuum may not be so much of a problem with the smaller ones, but I would recommend you only use the idea for evaporating
traces of residue or as traps and that you store the improvised implosion device inside one of those stainless sugar / coffee / tea jars from the
supermarket, to catch the bits if it pops.
Loading the bottle with some loose solid will also reduce the pop when something implodes.
[Edited on 3-1-2012 by peach]
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entropy51
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Quote: Originally posted by mr.crow  | I have a bunch of 250mL Pyrex media bottles and am wondering if its safe to pull a vacuum on them.
Instead of building a vacuum chamber I could just attach a hose barb to the cap and vacuum it in place. This is to get rid of solvent residue
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I have seen so many Pyrex media bottles break (explode?) in the autoclave that I really doubt that it's safe
to pull a vacuum in one.
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bahamuth
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Media bottles that explode in the autoclave is in my experience due to overfilling the bottles, not taking expansion of the liquid into account, and
as so the gas escapes the "soft from heat" cap-to-neck seal and when the liquid reaches the cap it's molecules are "many more" and often bigger than
the escaping gas and with a much much higher viscosity and as such one gets a hydraulic pressure on the flask and it shatters. Remember the pressure
inside the media bottle and outside in the autoclave will be equal or near equal unless one is hasty and removes the flask untill it cools.
As for vacuum applications I've used both regular Pyrex brand and Schott brand without ever imploding one. Never used larger than 1000 mL for that
purpose though, with me feeling alot more comfortable with the smaller sizes as 500 and 250 mL bottles. Usual vacuum pulled on those flasks would be
less than 1% of remaining atmosphere in my case.
Any sufficiently advanced technology is indistinguishable from magic.
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