evil_lurker
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Evil's not-so-amazing $20 OTC vacuum aspirator and recirculating station...
Yesterday I went to my local ace hardware store and purchased a waterbed drain and fill kit for $6 in hopes of getting something that could be used as
a decent ghetto aspirator.
As included in the package, the aspirator comes with a faucet adapter as shown.
http://www.acehardware.com/sm-rps-products-waterbed-drain-an...
However, since I plan on using it for some other purpose than what it was designed for, I had to break down and buy some brass adapters for the top
and sides.
The top fitting consists of a standard female garden hose fitting with a white faucet adapter. My setup is going to use 3/4 pipes, so I had get one of
these:
http://www.acehardware.com/product/index.jsp?productId=12734...
And the vacuum port also just happens to be a male garden hose fitting, so I had to get one of these:
http://www.acehardware.com/product/index.jsp?productId=12734...
And one of these:
http://www.acehardware.com/product/index.jsp?productId=12734...
Put it all together and it looks something like this:
So far I ain't hooked it up yet to my system, but a quick "sink test" showed very promising results... heck for that matter even blowing thru it pulls
a small but definatly noticable vacuum.
Coming soon... Part II: Setup and performance testing.
[Edited on 19-6-2007 by evil_lurker]
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in
beer.
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Pyridinium
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Sounds very promising. If you can even get a mild vacuum just by blowing through it, the thing can't be half bad.
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evil_lurker
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Unfortunately, the aspirator as tested (may have been some slight leakeage on the hose) was only capable of about 390 torr using tap water @32PSI.
Attempting to reduce the pressure only caused the vacuum to decrease, which pretty much confirms that my suspicions were correct the aspirator is
designed for moving large amounts of water, not air.
Coming soon: Pictures of setup.
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in
beer.
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not_important
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I think you're right on its design. But it would work well for filtration or solvent removal, if it could be done entirely in plastic it would be
nicely acid fume resistant.
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evil_lurker
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Here is what it looks like when its all put together...
I think I will add on another T fitting, gate valve, and hose barb so I can connect a condensor coolant line... the back is solely for draining and
pressure relief purposes.
While I'm at it, I'll raise it up some, add on a post apple scientific aspirator, and insulate the pipes to make my ice last as long as possible.
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in
beer.
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Organikum
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Man you have so much nice professional hardware and you are saving 8 bucks for a Nalgene Aspirator? Uups. I just counted what you paid for the parts
and you are actually not saving anything but yours is more expensive. Now explain me somebody this....
confused
/ORG
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Nerro
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It's the thought that counts 
You could also build an aspirator yourself quite cheaply, it should be pretty good but a lot of work and finetuning, esspecialy getting the jet to be
irregular in the optimal way can be a bitch (or so I'm told  )
#261501 +(11351)- [X]
the \"bishop\" came to our church today
he was a fucken impostor
never once moved diagonally
courtesy of bash
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evil_lurker
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Crazy as it may sound, aspirators ain't exactly easy to find around here... the biggest problem is that most of the chemical and laboratory suppliers
in the USA will only sell to institutions. Cynmar has them, but the last one I obtained from them shot out about as much water thru the side port as
the discharge. Post apple scientific has two to choose from, but they both have unknown supply connections. I think the seller on Ebay sells the same
brand as Cynmar, so I don't want a repeat performance. The other suppliers that I know of don't carry them.
Building a decent working aspirator is definatly a hit an miss type deal. Everything has to be exact for peak performance... hell even ready bought
ones can be somewhat flaky and vary in performance from what I understand.
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in
beer.
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Organikum
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Type "Nalgene" into Google and see what you get.
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gnitseretni
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i got the same aspirator. Wanna use it for distilling hno3. Probably won't last long i know but hell these things are cheap ill just get another one
:-)
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bio2
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I've used this same Nalgene aspirator for years with all types
of solvents, acids and bases and it still pulls as good as when new.
With cold water this aspirator will easily pull 20 Torr and works
at lower pressures than most lab aspirators. This with about
20PSI inlet pressure and 1.5 GPM.
Just remove the built in silicone check valve as it
is bound to fail eventually and restricts the flow.
.................................
http://www.nalgenelabware.com/products/productDetail.asp?pro...
6140 Vacuum Pump, Aspirator
Materials:
polypropylene
polyethylene tubing
Attaches to faucet for maximum free air pumping capacity of 11.5 liters per minute at a water flow rate of 6.5 liters per minute. Operates efficiently
with water pressures as low as 7.5 psig (.517 bar) for minimum water consumption. Ultimate vacuum: 28-1/2 in. (723.9 mm) Hg. Supplied with integral
check valve, 3/8-in. NPT connecting thread, and 4-3/4-in. length of tubing for insertion in discharge end.
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S.C. Wack
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I've been unable to obtain such a low vacuum from it,
http://www.sciencemadness.org/talk/viewthread.php?tid=7423&a...
or a plastic connector to a non-lab faucet water supply, only metal ones. It pulls no better than the base model Humboldt H-12020 metal one, just a
whole lot lighter and in less danger of corrosion.
Ward's sells the Nalgene one for $10.50.
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bio2
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The 36 Torr ultimate vacuum as stated by Nalgene must
be at 25 deg inlet water (standard condition?) at least that's
about what I get with it using warm water.
By cold I mean about 3-4deg water which is about as low as it goes in practice using ice.
There are certainly better aspirators in metal or glass but
they ain't $10-20.
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indigofuzzy
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Hypothetically speaking, could you get a better vacuum if you circulated mineral oil instead of water through the aspirator? It has a lower vapor
pressure.
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497
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How about a low melting metal alloy like Woods metal??  Just kidding. That would
get destroyed by acids..
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Klute
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I guess the viscosity of the oil would pose problems with pump and all, and might no get a good pressure du to the friction losses. And it would be
pretty dirty , spitting greasy droplets evrywhere
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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12AX7
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And you need a solvent-resistant pump.
Tim
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Panache
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| Quote: | Originally posted by 12AX7
And you need a solvent-resistant pump.
Tim |
Unfortunately no solution exists where you can run acids/bases/solvents/100C concurrently unless you make it out of nickel, which is what they are
forced to do at Al plants running the Haber process at pH14.
Yes you can either get acid/base resistant pumps, typically made from engineering grades of polypropylene. A decent italian gear pump (doesn't need
priming and can take some slurries without too much damage and run up to 100C fluid) is expensive even when cheap, around $AUS1500 landed here.
Although PP is resistant to all solvents generally that obviously is not the entire picture when it comes to making things that need to be operated
under load. Solvent creates craze apex's (apexie?) that under load can shatter the part.
So for solvent resistance you need stainless/monel etc and a decent gear pump will cost about the same again. In the US you would buy a US made pump
as they are probably better than the italian ones, however not widely available in Australia.
There are membrane pumps running off air using a teflon-esqu rubber copolymer, which are the closest you'll get to being resistance to
acid/base/solvents all in one, however the membrane does not last very long, you cannot use any slurries even mild ones, , anything above 50C you
would worry about and they make the worst jack hammer tapping noise!. As i found out after i bought one!! I started it up and thought, damm didn't
find out about how noisy it ran.
This probably is not useful information for anyone reading about how to make a aspirator for under $10 but interesting nonetheless!!!
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Panache
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| Quote: | Originally posted by bio2
The 36 Torr ultimate vacuum as stated by Nalgene must
be at 25 deg inlet water (standard condition?) at least that's
about what I get with it using warm water.
By cold I mean about 3-4deg water which is about as low as it goes in practice using ice.
There are certainly better aspirators in metal or glass but
they ain't $10-20. |
I was wondering about the glass ones, as i have a few, but have never had one running. I figured they were useful in decades gone by when acid
resistance was needed and polypropylene blending had not created the mechanical strength in the material available today. i had only speculated this
and was interested to see you can actually still buy them from Schott.
Is there a specific application where a glass vacuum aspirator has advantages? I would be interested.
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crazyboy
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| Quote: |
Is there a specific application where a glass vacuum aspirator has advantages? I would be interested. |
I would imagine vacuum distillation of volatile or particularly reactive compounds such as nitric acid or bromine.
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