zombiedude1
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Water Aspirator Help
I used a 1/2hp non-submersible water pump & a 5 gallon bucket with a metal water aspirator. I get a light vacuum (don't have a guage yet) which
will barely stick to my finger, and is very uneven with its vacuum pressure.
However, if I raise the water level in the bucket to where the end of the aspirator is dipped in the water, I get an extremely strong and level vacuum
(the water pump whines a little louder though)
I read around here that the aspirator should be 6-12" above the water level, and not in it. I'm not getting much vacuum that way. Could there be a
leak, or should I continue to use it this way since it creates a strong reliable vacuum?
I'm just worried about the pump getting damaged from the load)
(Using cold tap water, no ice, and a very small addition of antifreeze)
EDIT: It's also creating enough vacuum to vaporize the water coming out of the aspirator when partially submerged.
Badly drawn example:
[Edited on 3-11-2015 by zombiedude1]
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Detonationology
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Does the pump itself work well and produce an even, consistent stream? What kind of plumbing are you using? The design of the plumbing could also
produce an uneven distribution of water through the pipe, creating a sporadic vacuum. This seems like a really neat idea.
[Edited on 11-3-2015 by Detonationology]
“There are no differences but differences of degree between different degrees of difference and no difference.” ― William James
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zombiedude1
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This pump is a very cheap (but of great quality) electric ($32) centrifugal water pump & appears to have a very stable, powerful consistent
stream. Runs 370 watts, 10gpm. 1" inlet, 1" outlet, manual prime, dynamic head up to 240ft. Made of thick steel and aluminum. I lubricate it with
WD-40 before and after each use.
(http://www.ebay.com/itm/191287114408?_trksid=p2060353.m2749....)
The plumbing I decided against using PVC because I wanted to watch the water flow, maybe add a pond dye for fun.
I used thick clear vinyl (I think?) tubing (hose) for the plumbing, with a plastic reducer, down to another vinyl tube, down to the aspirator.
I have polyethylene tubing for the high vacuum pressure.
I also noticed at home depot they sell copper manifolds which could be used as a cheap vacuum manifold at only $12-25. I'm not sure if the copper is
good to use though depending on reactivity of chemicals; but it's an option.
I had an autocad design for the entire system, but I deleted it after I built this.
[Edited on 3-11-2015 by zombiedude1]
[Edited on 3-11-2015 by zombiedude1]
[Edited on 3-11-2015 by zombiedude1]
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Upsilon
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I may have just bought the exact same pump you describe, is it this one?
http://ebay.com/itm/New-1-2HP-Electric-Industrial-Centrifuga...
If so that's an epic coincidence
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zombiedude1
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Yes, it is. It's an amazing pump for this.
Anyway, my main point of posting this thread is:
- Why do I get a strong vacuum when the bottom of the aspirator is dipped in the water reservoir?
- Why do other posts/topics claim that you should NOT do this as it creates a weak vacuum, and that you should have the aspirator 6-12" above the
reservoir?
[Edited on 3-11-2015 by zombiedude1]
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JJay
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Are air bubbles getting sucked into the pump?
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zombiedude1
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I don't think so. I used a baffle to test any difference; and no difference was found.
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JJay
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I have no clue. I've seen that kind of setup before, but I usually use a vacuum pump. They aren't nearly as useful for removing cheap and nontoxic
solvents like water and ethanol, though.
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zed
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Hmmm. What is your rate of flow like?
Personally, I come from a less eco-friendly generation. I liked to open up the tap, let the water rage through the aspirator, and shoot down at least
a couple of feet, right into my sink trap. Worked pretty good.
Could be that submersion of the bottom of the aspirator, is improving vacuum, by preventing air backflow, into the pump. The ejaculated air bubbles
being entrapped in the more viscous liquid medium, that resists "leaking" backwards. Maybe.
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MrDoctor
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i have a similar issue. it has to do with the fact that the nozzle is too thin/direct and it shoots a stream all the way out of the aspirator without
forming any sort of water-lock. I have the same issue. i submerge the tubing-out of the aspirator. since i used to use a faucet for water, i just
directed the tubing into an old pepsi bottle, otherwise i had to make it waterlock in the tubing itself which would often fail, by bending or looping
it. Its possible this is also just a consequence of using water pressure that is much too high, but once its working, it works proper good. almost
hitting -700mmHg is insane for something so cheap, and my glass aspirator works even better. the water i had was around 50-80PSI
[Edited on 11-9-2024 by MrDoctor]
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Rainwater
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be the first centrifugal pump in the history of eBay. Even the jet turbine pumps
I install will have trouble with that spec.
So the issue you're going to run into with a centrifugal pump is head pressure. The more you have, the less mass flow rate you're going to see. It's
an exponential curve, meaning a small amount of head pressure will have a large effect on flow rate.
To minimize this, you need to minimize the restriction in the plumbing (tech term: reduce the tdh).
You can still use a water asporator, just not one designed for a high-pressure supply
Beware of air bubbles getting sucked into your pump, that will kill your ultimate vacuum level
"You can't do that" - challenge accepted
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