Thanatops1s - 21-1-2014 at 11:11
I was inquiring with someone about glassware for sale and the level of vacuum it can sustain. I've distilled plenty but never vacuum. He told me that
it's 0.098Mpa. Hopefully he understood what I was asking as his English isn't the best. If that's correct, how adequate is that for most purposes? I
have bought other things from him before and had no complaints. He sent the wrong thing once and immediately replaced it without even wanting the old
one back.
[Edited on 21-1-2014 by Thanatops1s]
Magpie - 21-1-2014 at 11:46
0.098MPa = 737mmHg where 760mmHg = 1 atm and 0mmHg = full vacuum.
So I would say that that glassware is not designed for any vacuum application.
bfesser - 21-1-2014 at 16:16
This question has been asked and answered multiple times. Please use the search function.
Funkerman23 - 13-2-2014 at 22:41
If this is Nanshin Sales on Ebay then this is a typo of his. Yes his English is poor, but he seams to be willing to help. I have been emailing him
back and forth regarding some kettles and he sent me the same value regarding a cylindrical 3 litter set up. I wish I knew if he meant ALL of his
glassware could stand that vacuum but I digress. as for the Search Engine I have to say that a custom Google search works a lot better but at too has
been stated many times.
Edit: IF I am right( which could be a crapshoot given the language barrier) Nanshin meant that the vacuum could go down to .0197atm or 15mmHg. I don't
really know at this moment if that's any good but this is what I have found.
[Edited on 14-2-2014 by Funkerman23]
Dr.Bob - 14-2-2014 at 12:58
The highest vacuum (on earth, not underwater) you will get is 1 atm of vacuum. There is no real difference between 1 atm or 0.9 atm of vacuum (ie, 0
torr or 0.1 toor or 0 psi and 1 psi). If a flask can withstand any level of vacuum safely, then it should handle a high vacuum just as well. Some
items should not be used for ANY vacuum work, like items with a square edge or large flat surface (unless designed special to handle that force.)
That is a very different question from what pressure can an item contain, as (differential) pressures for normal glassware can be anywhere from 1 atm
to 30+ atm or 300 psi and up. But no glassware should be subjected to more than a few psi of pressure unless the glassware, stoppers, and other
pieces are designed for it, as that is a much bigger risk than vacuum.
chemrox - 14-2-2014 at 13:54
If it doesn't have flat surfaces, ie any roundbottom, and it isn't scratched on the inside, it should handle 10*-7 or lower. Can anyone help me with
an oil diffusion pump setup?
ZIGZIGLAR - 16-2-2014 at 20:15
Some people, especially those who use vacuums in applied chemistry, refer to vacuum pressure in terms of guage. Guage = absolute presssure -
atmostpheric pressure. So in this case, he could've been referring to a vacuum of -737mmhg (-29inhg), which is the equivalent of around 23mmhg
absolute. This pressure would allow you to boil ethanol at 10c, and would be considered high vacuum and allow for most high boiling volatiles to be
boiled under 100c. There's usually little need to go below 40-50c as little decomposition is likely to occur at this temperature anyway.