Sciencemadness Discussion Board

Any way to draw vacuum with positive air pressure (like water aspirator or other)?

RogueRose - 10-1-2016 at 13:15

I'm trying to find if there are any ways to draw vacuum by using positive air pressure from something like an air compressor (short of tapping into the air intake of the compressor cylinder). If a tank of air was available, is there any way to draw a vacuum with it?

BromicAcid - 10-1-2016 at 13:28

Note that with a traditional water aspirator you can draw vacuum down to the approximate vapor pressure of the water you are using to run the aspirator. I.e., colder water is going to let you go lower in vapor pressure and get a better vacuum from your aspirator setup. If you try to just run air through a aspirator you are going to get next to nothing. At least as far as I know.

aga - 10-1-2016 at 13:47

The Veturii effect should cause some vacuum, although not a lot.

Better to construct or buy an air-driven pump and use that to pull the vacuum.

BromicAcid - 10-1-2016 at 14:37

-Brainfart- As soon as I read Veturii effect I was reminded that we have a scrubber at work that uses pressurized air to generate the vacuum that pulls vapors through the scrubber so it can be used to some effect, although I would still stand by my thought and aga's taht it will not generate a decent vacuum (not on par with a water aspirator at least).

aga - 10-1-2016 at 14:44

What intrigues me is that the air compressor must use electricity or some fuel of some type, so why can a Pump not be run on electricity or the same fuel ?

I have this insane image of the OP tapping into next-door's compressed air supply and using it to run their factory with re-purposed steam engines.

The smaller ones will be vintage Mamod static models, obviously.

mamod.JPG - 32kB

[Edited on 10-1-2016 by aga]

j_sum1 - 10-1-2016 at 19:10

For a nice example of using water to pull a vacuum, take a look at Doug's Lab YT channel.
https://www.youtube.com/user/DougsLab/videos