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Ubya
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[*] posted on 19-3-2018 at 11:39


18thTimeLucky? i'm from italy and i never use ebay.it, it doesn't show listings from everywhere and most of the times shipping costs are excessive, i shop from ebay.com (and sometimes from ebay.co.uk), there are more and cheaper listings from china with free shipping (most of the time) so i think it's better. anyway i bought that pump for about 10$ (i don't remember exactly) and free shipping to italy, so i can recommend to buy that pump from ebay, shipping time is about 1 month so if you are impatient order it from your technitian, if you don't mind the waiting go for it, i never had any problems (i bought stuff on ebay from chinese sellers many many times)




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18thTimeLucky
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[*] posted on 19-3-2018 at 13:42


Thanks for quickly reply Ubya. I will have to keep that in mind when looking at eBay. I don't mind waiting a month - I have plenty of time but not much money - so if I still can, I will cancel my order with my college science technicians tomorrow and buy a similar water aspirator pump to you (they are 3x cheaper!).



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"Amateur chemistry does seem like being in a relationship with someone very beautiful and seductive but has expensive taste, farts a lot and doesn't clean up after themselves, but you love them anyway" - a dear friend
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DavidJR
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[*] posted on 19-3-2018 at 23:15


Try deschem on aliexpress. I got my aspirator from them along with a lot of glassware. Very fast shipping.
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18thTimeLucky
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[*] posted on 20-3-2018 at 12:14


I managed to cancel buying the water aspirator pump from the list of equipment I asked them. I wish I could order chemicals through my college, would be so convenient...
I think I might try deschem then if you recommend them DavidJR.

It seems many people go for a similar 100Psi 12V DC water pump to couple with their water aspirator pump (I am guess this is because Nurd Rage recommended that design). Ubya, or anybody else, you seem to use a water pump like this, how do you power yours? (Nurd Rage does not mention how he does in his video) Do you just use a AC/DC 12V phone charger or similar? I have one laying around but it gives out 1.5A and I don't know if this would be enough if the water pump is 60W, I am not particularly brilliant at electronics.

This is a water pump I am interested in for reference: https://www.ebay.co.uk/itm/Hot-DC-12V-115Psi-High-Pressure-D...

Thanks in advance.

EDIT: Link was not working.
EDIT: A smily emoji keeps ruining my link! I will give a different link.

[Edited on 20-3-2018 by 18thTimeLucky?]

[Edited on 20-3-2018 by 18thTimeLucky?]




Yep, I have a chemistry blog!
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"Amateur chemistry does seem like being in a relationship with someone very beautiful and seductive but has expensive taste, farts a lot and doesn't clean up after themselves, but you love them anyway" - a dear friend
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DavidJR
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[*] posted on 20-3-2018 at 13:00


That's the exact listing I bought.

P=IV
=> 60W=I * 12V
=> I = 60/12 A
=> I = 5 A

So you'll need a supply capable of at least 5 amps. These pumps will run at lower current but the results will be less than satisfying...

Here's a link to the aspirator from deschem: https://www.aliexpress.com/store/product/Laboratory-Aspirato...

They also have a copper version for a slightly increased price.
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18thTimeLucky
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[*] posted on 20-3-2018 at 14:00


Thank you, I apoligise for the spoonfeeding, making you do such a simple calculation - I expected it to be way more complicated than that. Thanks for the link, although deschem's eBay account seems to be selling atleast the stainless steel one cheaper for some reason so I think I will get it from eBay.

Seems like I now have a shopping list of:

https://www.ebay.com/itm/Stainless-Steel-Aspirator-Pump-Humb...

https://www.ebay.co.uk/itm/Hot-DC-12V-115Psi-High-Pressure-D...

https://www.ebay.co.uk/itm/AC-Converter-Adapter-DC-12V-5A-Im...

Hopefully this will pull a decent vacuum.
Again, thanks for the help Ubya and DavidJR, much appreciated.




Yep, I have a chemistry blog!
18thtimelucky.wordpress.com

"Amateur chemistry does seem like being in a relationship with someone very beautiful and seductive but has expensive taste, farts a lot and doesn't clean up after themselves, but you love them anyway" - a dear friend
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Ubya
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[*] posted on 20-3-2018 at 16:21


Quote: Originally posted by 18thTimeLucky?  


It seems many people go for a similar 100Psi 12V DC water pump to couple with their water aspirator pump (I am guess this is because Nurd Rage recommended that design). Ubya, or anybody else, you seem to use a water pump like this, how do you power yours? (Nurd Rage does not mention how he does in his video) Do you just use a AC/DC 12V phone charger or similar? I have one laying around but it gives out 1.5A and I don't know if this would be enough if the water pump is 60W, I am not particularly brilliant at electronics.

This is a water pump I am interested in for reference: https://www.ebay.co.uk/itm/Hot-DC-12V-115Psi-High-Pressure-D...



i use a 15v 60w laptop charger to power the pump, but soon i want to upgrade it to a 120W 12V LED power supply i found one on ebay for cheap , i could use the extra 60w for other things i might need in my DIY fumehood


[Edited on 21-3-2018 by Ubya]





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[*] posted on 6-5-2018 at 19:20


Just finished my new vacuum pump yesterday and testing it this morning. It is powerful. Maybe the pressure pump is a bit of overkill but in combination with the tap I can easily control the pressure delivery. I’m yet to test it with a water distillation to get a gauge of what vacuum it can attain but I’m sure it will reach the optimum vacuum that the aspirator can reach. I found the small caravan water pumps do work but the diaphragm shits out after a few hours run time. This pump is also quieter. The pump I have now cost me 30$ second hand and the plumbing fittings all up cost me 10$ since I had some of them already the aspirator was 15$ from Deschem so it’s well under 100$ to make it and it will prove to be very useful for some distillations where I don’t want to subject my rotary vane pump to like acidic and solvent laden solutions. The reservoir is sufficient enough to ass ice bricks and such to keep it cool too.

EDB55D0C-B38F-4F7B-9955-C7491F80B889.jpeg - 3.3MB




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there is a way.

Like many of us i also do Youtube.... AllCheMystery!
https://www.youtube.com/channel/UCWbbidIY4v57uczsl0Fgv7w?vie... Fixed link. You can see it now!
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Panache
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[*] posted on 13-5-2018 at 00:15


Quote: Originally posted by NeonPulse  
Maybe the pressure pump is a bit of overkill but in combination with the tap I can easily control the pressure delivery.


Thats like saying by building a blast wall we are controlling the explosion, you'd be far better off controlling the pumps motor as soon enough the back pressure is going to affect your mechanical seal, or worse your motor.
But technically i guess you're correct and if works and only see's intermittent use then fine and its looks kind of sculptural with that bend in the hose...
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[*] posted on 13-5-2018 at 00:57


Quote: Originally posted by Panache  
Quote: Originally posted by NeonPulse  
Maybe the pressure pump is a bit of overkill but in combination with the tap I can easily control the pressure delivery.


Thats like saying by building a blast wall we are controlling the explosion, you'd be far better off controlling the pumps motor as soon enough the back pressure is going to affect your mechanical seal, or worse your motor.
But technically i guess you're correct and if works and only see's intermittent use then fine and its looks kind of sculptural with that bend in the hose...


The motor looks like an induction type so it will not be easy to control it.

A bypass would be simpler i.e. put the tap between the output and input.
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Panache
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[*] posted on 13-5-2018 at 01:26


Quote: Originally posted by wg48  
Quote: Originally posted by Panache  
Quote: Originally posted by NeonPulse  
Maybe the pressure pump is a bit of overkill but in combination with the tap I can easily control the pressure delivery.


Thats like saying by building a blast wall we are controlling the explosion, you'd be far better off controlling the pumps motor as soon enough the back pressure is going to affect your mechanical seal, or worse your motor.
But technically i guess you're correct and if works and only see's intermittent use then fine and its looks kind of sculptural with that bend in the hose...


The motor looks like an induction type so it will not be easy to control it.

A bypass would be simpler i.e. put the tap between the output and input.


i concur, i wasn't really thinking about what i was saying at that point i just wanted to use that blast screen to control the explosion bit.....

[Edited on 13-5-2018 by Panache]
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[*] posted on 13-5-2018 at 02:58
What is the attraction to re-circulating vacuum pumps ?


So far I have been using a cheap small 12 Vdc motor vacuum pump like this https://www.ebay.co.uk/itm/DC-12V-24V-80Kpa-Micro-Piston-Vac...
for 'vacuum' filtration and reduced pressure distillation.
Admittedly over four years of use/abuse it's performance has dropped a little, but it works just fine.

What is the benefit of a recirculating water pump driven vacuum aspirator ?
Surely the water needs de-gassing and cooling ?
Why is all the extra effort and cost beneficial ?

P.S. I have a dual-stage rotary but it never gets used for chemistry,
mainly due to fear of damaging it.
(and the vacuum would boil most common liquids at room temperature)




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[*] posted on 13-5-2018 at 04:28


Quote: Originally posted by Sulaiman  
So far I have been using a cheap small 12 Vdc motor vacuum pump like this https://www.ebay.co.uk/itm/DC-12V-24V-80Kpa-Micro-Piston-Vac...
for 'vacuum' filtration and reduced pressure distillation.
Admittedly over four years of use/abuse it's performance has dropped a little, but it works just fine.

What is the benefit of a recirculating water pump driven vacuum aspirator ?
Surely the water needs de-gassing and cooling ?
Why is all the extra effort and cost beneficial ?

P.S. I have a dual-stage rotary but it never gets used for chemistry,
mainly due to fear of damaging it.
(and the vacuum would boil most common liquids at room temperature)


- Allot of places you are charged for the water per gallon, So think about the amount of water needed for a long distillation! It adds up fast.

- Compounds absorbed by the water my render it illegal to discharge down the drain (re circulation nullifies this issue)

- City water pressure can fluctuate heavily unless you have a hydro static booster pump (Most good labs and medical buildings will have this equipment) House tend not to have these so your vacuum can fluctuate unpredictable.

- Water condition, some places have crap loads of salts dissolved in water (Like my place) that will corrode or plug aspirator, my water will do both, re circulation eliminates this issue by being able to use distilled, which further offers better predictable vacuum

just a few off the top of my caffeine deprived brain.
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[*] posted on 13-5-2018 at 05:12


Quote: Originally posted by XeonTheMGPony  
Quote: Originally posted by Sulaiman  
So far I have been using a cheap small 12 Vdc motor vacuum pump like this https://www.ebay.co.uk/itm/DC-12V-24V-80Kpa-Micro-Piston-Vac...
for 'vacuum' filtration and reduced pressure distillation.
Admittedly over four years of use/abuse it's performance has dropped a little, but it works just fine.

What is the benefit of a recirculating water pump driven vacuum aspirator ?
Surely the water needs de-gassing and cooling ?
Why is all the extra effort and cost beneficial ?

P.S. I have a dual-stage rotary but it never gets used for chemistry,
mainly due to fear of damaging it.
(and the vacuum would boil most common liquids at room temperature)


- Allot of places you are charged for the water per gallon, So think about the amount of water needed for a long distillation! It adds up fast.

- Compounds absorbed by the water my render it illegal to discharge down the drain (re circulation nullifies this issue)

- City water pressure can fluctuate heavily unless you have a hydro static booster pump (Most good labs and medical buildings will have this equipment) House tend not to have these so your vacuum can fluctuate unpredictable.

- Water condition, some places have crap loads of salts dissolved in water (Like my place) that will corrode or plug aspirator, my water will do both, re circulation eliminates this issue by being able to use distilled, which further offers better predictable vacuum

just a few off the top of my caffeine deprived brain.


Those all seem to be reasons to not use an aspirator ?




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[*] posted on 13-5-2018 at 05:23


No, just to use a self contained system, Aspirators can with stand things that will destroy a rotary van pump, and a cryotrap for a rotary van pump is allot more costly then a simple aspirator set up.

I've been working on a multistage PELT set up for a cryo trap, trying to figure out some different topolagies and geometries for both vacuum freeze drying and for vacuum trap. you need -80 to ensure most substances are properly scrubbed from damaging the pump.

The system must be able to run for 24h as well so it is no small task! most use autocascade systems.

So either you invest a couple grand for that, or less then a hundred for aspirator in a self contained system.
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[*] posted on 10-6-2018 at 20:15


Quote: Originally posted by NeonPulse  
Just finished my new vacuum pump yesterday and testing it this morning. It is powerful. Maybe the pressure pump is a bit of overkill but in combination with the tap I can easily control the pressure delivery. I’m yet to test it with a water distillation to get a gauge of what vacuum it can attain but I’m sure it will reach the optimum vacuum that the aspirator can reach. I found the small caravan water pumps do work but the diaphragm shits out after a few hours run time. This pump is also quieter. The pump I have now cost me 30$ second hand and the plumbing fittings all up cost me 10$ since I had some of them already the aspirator was 15$ from Deschem so it’s well under 100$ to make it and it will prove to be very useful for some distillations where I don’t want to subject my rotary vane pump to like acidic and solvent laden solutions. The reservoir is sufficient enough to ass ice bricks and such to keep it cool too.


Did you get a chance to test your new recirculating aspirator? How much vacuum did it draw (mm Hg, boiling point of water, etc.)? Also, what are the specs of your pump?
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