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iodide
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Advice on Pond Pump for aspirator setup?
There are several, well-priced pond/aquarium pumps on ebay, offering in excess of 400 gallons per hour ("GPH" . Lacking a conversion ratio, I am at a loss as to how to determine what GPH rating
would be best suited to allow for a relatively strong vacuum in connection with a nalgene aspirator.
Do any of you know - either from experience or through the use of a formula - what would be an appropriate rating?
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chemoleo
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The transfer rate per hour does not necessarily relate to the ability to create a vacuum, at all.
Take a fan for instance. Great ability to move air, but impotent on creating a vacuum. Admittedly an aqu. pump is likely to have a diff. design,
nonetheless it isnt designed for vacuum, so I wouldnt place much trust into it.
A peristaltic pump is likely to be more effiicient, and relatively easily to make at home.
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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Oxydro
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I think he means, use the pump to force water through an aspirator to create the vacuum that way.
So, basically, the question is, how many gallons an hour at what pressure does it take to drive an aspirator effectively.
And the answer is, I don't know. But I think I figured out the question anyway. 
Ah.... the pump on this page takes 1 gpm (60gph) to operate. but this is at 35 psi, which iirc translates to >80 feet of head for a fountain, so not what the
typical pump is designed to handle.
"Our interest's on the dangerous side of things" -- Browning
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Lambda
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Big Dick pumps
Sorry about this, but these pumps are good 
How natural penis enlargement programs work:
http://www.veseliba.info/enlargement/page-penis-pump.html
I found this link on the same page to be of a more chemistry addaptive nature:
http://www.veseliba.info/enlargement/go.php?http://www.1-in-...
Refrigerator motor vacuum pumps (good vacuum, but susceptible to corrosive gasses)
Concerning Homemade Vacuum Pumps:
http://www.sas.org/E-Bulletin/2003-08-01/labNotesAS/body.htm...
A Homemade Vacuum Bagging System:
http://www.badger.rchomepage.com/vacbag.html
These are good, they can take nearly everything that is corrosive (vacuum depends on water temperature)
Water jet vacuum pump or aspirator (two designs):
http://www.frogfot.com/misc/waterjetvac.html
[Edited on 10-7-2005 by Lambda]
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iodide
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Not sure I understand, Oxydro...
"Ah.... the pump on this page takes 1 gpm (60gph) to operate. but this is at 35 psi, which iirc translates to >80 feet of head for a fountain,
so not what the typical pump is designed to handle."
So, if the pumps on ebay are rated at a couple hundred gph, this should be an excellent match for a water aspirator as it will create an excellent
vacuum, right?
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unionised
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You need to know the maximum back pressure that the pump will handle. Since the aspirator needs about 80 feet and the best I have seen for garden
water pumps is about 10 feet it won't work.
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Oxydro
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Now, the funny thing is, I just basically made a wild-ass guess on the 80ft. I knew there were about 30-odd ft to 1 bar (14.7psi) so I figured
I'd be in the right ballpark.
Now, time to calculate:
A ft^3 of water is 62.5lbs. A ft^2 is 12*12=144 in^2.
so feet/psi = 144/62.5=2.30.
35*2.30 = 80.64. ft of head-equivalent needed by the aspirator for full vaccuum.
I am good. Scratch an "o", I am God. LMAO
What you need is a pump designed for household water supply. Either that or attach a bunch of the pond pumps in series .
Or, I suppose if you can't afford this, you could stoop to a lower level and run them off the tap like everyone else does .
"Our interest's on the dangerous side of things" -- Browning
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Blind Angel
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Oxydro: I'm here to convert you to metric system.
Repent yourself demon, the old english system time is resolve, doom is near for those who still use it. Embrace the path of light, meter and grams.
Forget your old sinfull way of calculation in variable base, turn yourself to the decimal system.
P.S.: I found an old pump for astmatic in my wardrobe (like the one used in hospital) i'll have to check how much it can suck though but it seem
to work, slowly but surely.
/}/_//|//) /-\\/|//¬/=/_
My PGP Key Fingerprint: D4EA A609 55E4 7ADD 8529 359D D6E2 33F6 4C76 78ED |
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12AX7
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I said it before on the same subject...
Screw the French.
Tim
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Oxydro
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12AX7:
I do [screw the French].
(my girlfriend is Acadian)
He [Blind Angel] probably does too.
(he's a Quebecer)
As for metric, I quote myself:
| Quote: |
I think that Imperial should definitely be eliminated. But that's hypocritical - I use it myself far too often. I am trying to improve though
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"Our interest's on the dangerous side of things" -- Browning
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unionised
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Ho Hum, It seems that in a desperate attemt to be xenophobic you kind of missed the point that you need 2 numbers (at least) to specify a pump.
Rather more tellingly, not one of you used the correct units for pressure (Pa) or flow rate (M^3/s).
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gorilla
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Scientific Units
This is called 'Science Madness': we should all be scientific units, right?
Scientific units means SI. Look it up. Don't post crap.
A typical aspirator requires 12 Litres / minute at 150 KPa. Work it out. That's around 3 gallons per minute at 1.5 bar. Most pond pumps
won't generate the pressure.
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unionised
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Litres/ minute isn't an SI unit, on the other hand, it's a bit more practical than cubic metres/ second. (Equivalent to 60 tons of
water/minute)
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bio2
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........what GPH rating would be best suited to allow for a relatively strong vacuum in connection with a nalgene aspirator.........
Nalgene has the specs on their website for this polypropylene aspirator which works very well.
I don't think you will find a pond pump up to the job. I use a 1/4hp pump rated at thier specs near shutoff on the pump curve. Pulls 12mm with
cold water no problem. This aspirator takes less pressure than any other I've seen. The capacity is a little low but sufficient for a 6-10
liter setup just takes a while to pull down.
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demax
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Hey Bio2,
just had a look see at the nalgene page and cant find the graph referred to.
Demax is wanting to put together an efficient hydro aspiration system and would love some ideas on putting together a simple rig. UTSE but sought of
get the impression that some are going about this the hard way.
Demax has some of his own ideas about this but if peeps are having good results then would love the hear about them.
take it to,
demax
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arche
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See how this works for you.
Attachment: aspirator.html (4kB)
This file has been downloaded 1056 times
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bio2
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I think I used 25 or 30PSI at their flow rate to size the pump. Pump only draws 2.3amps@120v and is a water pump used for house pressure from a
storage tank. Since the flow is very little to maximize efficiency and minimize the NOISE choose the pressure to be near the pumps shut off head.
Plumbed to a 3gallon cooler it does a good job and only needs a trickle of fresh water if you will be running it for a long time.
Nalgenes 7.5PSI statement is mainly for filtering use, not to attain the maximum stated vacuum. Take out the shitty flapper check valve as it will
surely fail and only after you start to rely on it.
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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demax
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Thanks for the replies. I have a couple of questions though?
If one is using a 1/3 or even 1/2 horsepower pump is this not going to be to strong for the aspirator, that is is the engine going to be overworked
because it is beng asked to pump to much water through something as small as the aspirator?
The system designed by polythenesam looks quite nice and simple to construct any thoughts on how much vacuum something like this would pull. Motor
only looks to be small from memory.
These 30-40 psi pumps would pull how much vacuum? Looking for something real low ;-)
take it to,
demax
[Edited on 1-8-2005 by demax]
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demax
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Demax has found two pumps for his aspirator rig and is hoping someone can judge their worth. The specs for pump:
A) Motor Output: .77HP or .58 KW
Motor Input: 1.1256 HP or .84 KW
Max Total Head: 28 M or 91.8 ft
B) Motor Output: .71 Hp 0r .53 KW
Motor Input: .99 Hp 0r .74 KW
Max Total Head: 37 M 0r 121.3 ft
Calculation of the Psi:
A) 91.8 x .4335 = 39.79 psi
B) 121.3 x .4335 = 52.58 psi
Are these pumps to powerful for an aspirator setup. The seem to sort of fall within the specs as provided by Arche. My preference is for Pump B simply
because it is quieter than pump A but will be guided by others.
Thanks
take it to,
demax
[Edited on 4-8-2005 by demax]
[Edited on 4-8-2005 by demax]
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Tacho
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0,71HP?
I used a 0,25HP pump and used 2 aspirators in parallel, because there was too much pressure. 37 meters head is like having a reservoir at the top of a
13 floors building. Any leak in your pipework will squirsh water to the next block. Your tubes will have to be very tightly fit.
If I had to buy another pump, I would buy one fully built in plastic. I had problems with rust that made my pump get stuck a few times.
Let me quote HRH_Prince_Charles that made excellent posts about aspirators and pumps in the homebrew aspirator thread.:
"The thing that governs the limiting pressure of the water-jet pump is the velocity of the water jet"
"The typical pumping speed of a lab. water-jet pump is 67 ml/s or 0.15 cfm"
"That 1/4 hp pump sounds almost perfect Tacho. I've looked everywhere, and the best I could get was a 370 W model. It does give 25 L/min at
15 m head, so I could run a pair of water jet pumps. "
"A typical water-jet pump only requires around 30 W of power to run! (calculate from pressure drop x flowrate). However, a typical pump is only
20% efficient at driving the water - the other 80% goes into heating the water in the pump. So, to get 30 W of water power for the water jet, you need
a pump of
100/20 x 30 W = 150 W (0.2 HP)"
"Note also that the maximum head for a pump is at zero flowrate. In use, the head will be lower. My pump is 35 m max. head but only 15 m head at
25 L/min. "
You should read that thread carefully again before buying a pump.
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bio2
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Demax;
These pumps for most aspirators are definetly overkill. The cost to run and the noise would be much more than a 1/4 or 1/3 HP which is plenty
depending on the aspirators specs.
There is a large difference in aspirators and for best operation the pump should be matched. For most any normal lab use the smaller flow, lower
water pressure types are fine.
.....Motor Input: 1.1256 HP or .84 KW...
During a 10 or 12 hour distillation you will be sorry you have this monster neverminding the electricity cost. I run mine even a couple days on the
dessicator at times and have it under the house about 10 feet away.
.....Max Total Head: 28 M or 91.8 ft......
As was mentioned this is at shutoff! The pressure at the required flow is all that is meaningful. The reason I mentioned to choose one near shutoff is
because a centrifugal pump draws the least current at the 0 flow condition and for the pressure needed with an aspirator which has very little
relative flow compared to what these types of pumps are designed for the operation point will be near the shutoff anyway.
The Nalgene plastic one works great at 25PSI 1.5 GPM and some larger metal ones require 60PSI and a lot more flow. Do NOT get a metal aspirator they
corrode quiclkly. I had a nickel plated one that lasted maybe 6 hours pumping formic acid fumes!
An all plastic head, magnetic drive pump is the best choice. March and Little Giant companies are two that are very popular.
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demax
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Ok i am confused by all this talk of psi etc when it comes to selecting a pump for a water aspirator.
This aside i have a Nalgene aspirator that claims it will acheive its maximum free air pumping capacity at a water flow rate of 6.5 L per minute.
Thus if 6.5 L per minute is flowing through this device it will be operating at its or near full potential?
Today i found a fountain/pond pump that at 1 meter of head will pump water at 16 L per minute.
I plan on placing the aspirator about 75 cms vertically above this pump and oh about 50cms horizontally out from the pump.
This pump has a power output of 240V.
Do you guys think a unit like this will be strong enough?
Thanks
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Eclectic
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No, it won't have enough pressure to drive the aspirator. You need a soda fountain type pump that can produce 35-80 psi of pressure (at least 25
meters head) at 1.5-3 gallons per minute. (6-12 L/min).
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PainKilla
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Shurflo pumps work great, and are available cheaply on ebay.
http://motors.search.ebay.com/shurflo_W0QQfromZR40QQpqryZshu...
The 30psi works wonderfully, though I prefer traditional vacuum pumps (rotary vane-oil etc... they cost about the same, and create much better
vacuums).
[Edited on 8-5-2007 by PainKilla]
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bio2
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These Sureflow rubber impeller type pressure pumps are not intended for continuos duty of hour after hour and under the best of conditions the
flexible impeller won't last long even not
taking into account the effect of various solvent vapors.
These pumps are also positive displacement hence the pressure
switch mounted to the head. Also they are noisy as hell!
The primary use of this type of pump is water transfer and
bath/shower intermittent use.
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