xwinorb
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Vacuum aspirator connection
I found a Web site that sells one interface from 3/4 in hose to 3/8 in, vacuum aspirator.
The name is "Avogadro's Lab Supply".
To attach it to a normal water faucet, it is necessary to have also another part that screws in the faucet and converts from faucet srew size to 3/4
in hose, male. Can be found in hardware stores. The site above has some more information on this also.
Just unscrew the aerator tip from your faucet, screw in the two parts in series. I suggest to use a bit of teflon tape on the aspirator thread.
A bit more info on aspirators : A good one should be rated at 28.5 in Hg. That means, the vacuum is :
( 760 - 28.5 * 2.54 * 10 ) = 760 - 723.9 = 36.1 mm Hg.
Rounding a bit, that means a 35 mm Hg vacuum. It will boil water at 31 C, easy to verify.
As long as you attach everything properly, it is easy to achieve this vacuum. I have seen posts of other users in this board, from people that
apparently have a very good knowledge of chemistry and were having trouble with something so simple as this.
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Chainhit222
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Not to mention you can build a vacuum pump out of an aspirator and a jacuzzi pump
http://img693.imageshack.us/img693/9352/dsc0388i.jpg
The practice of storing bottles of milk or beer in laboratory refrigerators is to be strongly condemned encouraged
-Vogels Textbook of Practical Organic Chemistry
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xwinorb
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Since you have mentioned the high powered aspirator setup :
Do you know how much the increase in vacuum relates to the water temperature, and how much it relates to the water flow ?
I think I have read somewhere that there is a theoretical limit to the vacuum you can achieve, and that that number is the water pressure at the
temperature of the water flowing through the aspirator. The pressure of 28.5 is the maximum I ever saw one aspirator rated, and it seems close to the
water pressure at 25 C ( in fact more something like 32 C ).
If you have the water contained in a box like that, then you can add ice, maybe ice and salt, and improve the vaccum by temperature control also.
If you increase only the water flow speed can you achieve an increase in vacuum ?
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watson.fawkes
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No. Increasing the water
flow increases the pumping rate, which is usually not a problem for a small setup.
Look up the vapor pressure of water to see the ultimate pumping limits of an aspirator pump.
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