Author Topic: water aspirator  (Read 821 times)

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ekolo

  • Guest
water aspirator
« on: March 15, 2004, 08:21:00 PM »
I read the post on Rhodiums site(

https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/aspirator.html

) about building an water aspirator but how strong is an water aspirator in Inches Hg if the water pressure of the pump is 40psi.

silenziox

  • Guest
I'd suggest using kilopascals and mmHg instead
« Reply #1 on: March 15, 2004, 08:42:00 PM »
I'd suggest using kilopascals and mmHg instead of psi/bar /inHG..

http://www.chemsoc.org/exemplarchem/entries/pkirby/exemchem/Nomograph/Nomograph.html



There is also Imperial-version of this... I won't search it down.  8)

Did you try to search google for words "psi inch hg"?
Here's good table for high vacuum:

http://www.lds-vacuum.com/conversion.html




1 micron (u) Hg = 0.001 mm Hg = 10-3 mm Hg
1 millitorr = 1 micron (u) Hg = 0.01 mm Hg
1 millibar (international) = 0.75 mm Hg
1 bar (international) = 106 dyne /cm2 - 29.53 inches Hg
1 barye = 1 dyne/ cm2
1 newton/m2 (pascal) = 10 dyne/ cm2 = 7.5x10-3 torr
1 newton/m2 (pascal) = 7.5 millitorr = 7.5 micron
1 millimeter Hg = 1000 microns = 10-3 microns = 1 torr
1 millimeter Hg =1.333 millibar = 133.3 newton /m2
1 millimeter Hg = 0.03937 inches Hg = 0.01934 psi
1 torr = 1 mm Hg = 133.3 newton/m2
1 atmosphere = 760 torr = 14.7 psi
1 psi = 2.036 inches Hg @ 32oF = 51.72 torr
1 psi = 2.041 inches Hg @ 58.4oF
1 inch Hg @ 32oF = 0.4912 psi
29.921 in Hg @ 32oF = 14.696 psi = 760 torr
30.00 in Hg @ 58.4oF = 14.696 psi = 760 torr

And the answerfor your question is: 40psi = 81,44 Inches Hg @ 32'F


ekolo

  • Guest
no i did not do a google search just wanted to
« Reply #2 on: March 16, 2004, 11:47:00 AM »
no i did not do a google search just wanted to se if someone had some expirience with it. its because i have smal water compresor and its a powerfull one, its working presure is at 1600psi or about 110 bars. just wanted to know how strong such water aspirator could bee if it was at 40psi. thanks for the help.

just a question is such a water aspirator(40psi) good enough to vacuum destil ketone or sassafras oil or is it imposible. thanks.

ApprenticeCook

  • Guest
fine
« Reply #3 on: March 16, 2004, 01:16:00 PM »
That should be fine, just need to find out the specs of your aspirator, some are different, example swims aspirator at 1Kg/cm2 water/air supply can pull 15mmHg.

The way swim does it is to have a "T" joint in the vacuum line between your aparatus and aspirator, connect the aspirator straight through and a vacuum gauge (automotive one is fine, but they are usually in InHg not mmHg) to the other port, this allows you to see the vacuum reading and using the nomograph here:

https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/nomograph.html


To  find the boiling point of the substance at that pressure.
Convert mmHg, InHg, Torr, atm etc... here:

https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/conversion.html



Hope that helps.
-ApprenticeCook

a3d0a3m

  • Guest
Pull
« Reply #4 on: March 18, 2004, 06:28:00 AM »

killabeezwax

  • Guest
kitchen faucet pressure
« Reply #5 on: March 18, 2004, 09:54:00 AM »
I know that a kitchen faucets pressure is sufficient enough for a 30 mmHg (system was very chopped together-sort of a dry-wet run :), pressure may actually be higher).  I'm betting your 40psi is much more substantial than a kitchen faucet.


moo

  • Guest
Your water pressure has to be real shitty or...
« Reply #6 on: March 18, 2004, 11:02:00 AM »
Your water pressure has to be real shitty or your aspirator way too big to end up in a situation where the vacuum was not dictated by the temperature of the water or actually the vapour pressure of water at that temperature.