Lab Equipment: Aspirator Vacuum Pump

[@theCodyReeder]

"I wonder how mercury would do if run through an aspirator pump" -- dangerous thought of the day

[@AltoidJTP]

Assuming you could get it flowing fast enough, the low vapor pressure of mercury should make for a nice vacuum.

[@dawidflak2239]

Cody'sLab i'd love to See this in action. Maybe because of the high density of mercury you wouldn't even have to use pump? Just a reservoir placed at a high elevation, we both know u have more than enough quicksilver to do it. Give me a shout in your vid if u decide to do it :D

[@Lossanaght]

I believe that is called a Sprengel pump

[@Lossanaght]

Gummy Bugz Not sure, it's entirely likely he found it on his own. If not I wish I had thought to post the link to the self acting version that I posted in his video's comments.

[@hamishferguson4166]

that and the fact cody treat Hu like water

[@richardaudet4158]

Good day. Vacuum pump aspirations (ie hopes and dreams) have, so far, lead to failure and its keeping me from getting started on any project! To keep things straightforward, could any and all readers suggest precise Brand, Make, Model info OR specific operational statistics (specs) that they currently are using (and functions well)? Frustration levels are hitting the ceiling! And bank balances the basement!

[@NurdRage]

Maybe i'll concentrate hydrogen peroxide or sulfuric acid with this system. Anyway, I'm still remaking all the chemicals for the pyrimethamine synthesis so that's taking awhile. i'm not sure when the next video for that will be up. Next immediate video might be something on matches, we'll see. On a different note, good luck to all you students who will be returning to school/college/university soon.

[@jamie91995]

Thank you, Im Going back tomorrow, and sadly I was forced to quit chemistry so now everyone at school will be asking me about it...

[@ethanping1010]

Yes that would be amazing to see you concentrate hydrogen peroxide please really consider making that video... Thank you

[@unity2702]

Do you disguise your voice?

[@user-zu1hi4br4t]

do you edit you're voice and why. you don't have to answer that I was just wondering. by the way you're channel is great keep up the great work! love your vids.

[@redmohawkguy1]

Thank you NurdRage. I will be starting college on September 3rd. I'm going to major in, you guessed it, chemistry, your videos are what originally sparked my interest in the subject.

[@gigglysamentz2021]

Distilling water at 39°C with your set up is impressive ! Well done :)

[@NurdRage]

It gets BETTER! :)

[@gigglysamentz2021]

Oh god I just watched the rest of the video: 19°C??? This is crazy !

[@31946mar]

After a couple of tries, I got a 14 mm x 1.0 mm pitch die that perfectly fits the inlet an aspirator that appears identical. While waiting on it, I had an experience where another aspirator would do -7" Hg with < 6 mm separation from my fitting on the pump and -28" Hg with an 18" tube. Theory is that aspirators require laminar flow input and 50 pipe diameters are required to re-establish laminar flow after passing through a pump or past a 90 degree elbow. But, enough power and it does not much matter but at the edges, it can.

[@AllChemystery]

Well i finally got around to testing this. I used pretty much exactly the same setup- the same cheap aspirator, the exact same water pump, some tubing and a square mop bucket as the reservoir. The results were pleasing. i was able to distill acetone at 18c. the flask was so cool it was even water condensate on the outside of it. my lab was a rather warm 29.8C in contrast. the reservoir water temp was not ice cold so it probably would be able to distill at a lower temperature still. The only thing i found was a need to have the aspirator positioned vertical unlike what you have here and the vacuum was quite strong too when i tested it for a vacuum filtration as well. Thankyou for showing this setup! i had my doubts but it really does work as well as you have demonstrated here and i see how useful this little device really is.

[@vantablack9882]

how long can this diaphragm water pump work ?

[@nicolesomerstein6863]

Hello! Did you use an aspirator like the one he shows here? Or did you use a lab grade aspirator? I am attempting this set up with a lab grade aspirator (also called a filter pump; a bit longer and all metal) and have not been able to pull a vacuum strong enough to boil my water solution.

[@31946mar]

Same problem using $10 aspirator (Actually $26) and slightly more powerful pump but can only draw -6 in Hg.

[@L.Parisi]

on ships this is called "ejector", used for distillation of sea water, to obtain fresh water with minimal use of heat (in fact the waste heat from the engine is used), wonderful Venturi effect

[@goodfeller2]

Very helpful. I always wanted to know a cheap and effective vacuum system. I had always used an aspirator from a pet store used for cleaning fish tanks but, that was a huge cost of water. Not to mention the effects on the environment. This is a perfect set-up that I wouldnt mind being abusive to since the components are so cheap. secondly I wasnt aware that you could lower the boiling point that low. My aspirator must suck because I could only get it down 15-20 degrees. This is hugely useful for not only simple things like filtration but also distilling those pesky high boiling point compounds that like to decompose at high temps. Thanks Nurdrage and keep up the good work.

[@31946mar]

Not sure where to put this comment but I need help. I rigged up a pump a little bigger than his with an identical appearing venturi and could only get down to -6 in Hg. Does this video ever come out and say what he got?

[@user-tm4ne4vf1u]

Maybe you should construct your outlet so that water can go out straightly and not through whole tubing, as going through the tubes requires additional effort so it may reduce your vacuum

[@bormisha]

I remember having these vacuum pumps made as glassware as I was a kid. Couldn't use them for vacuum pumping those days, though, because of a lack of a high pressure water source. But they made great toys for the bath. I imagined them to be submarines.

[@JackSinger]

I love these type of videos!

[@NurdRage]

Me too!

[@user-py9cy1sy9u]

Me three

[@WhatWillHappenIf0]

What a great video. so educational 😊😊

[@NurdRage]

Thanks!

[@WhatWillHappenIf0]

NurdRage Welcome :) Your videos are all educational. :)

[@multispore8250]

Mr. NurdRage, Thank you for this video, we need more people like you

[@barba928]

The reason those 12v diaphragm pumps seem amazing is a brush type 10,000 rpm universal motor. It will shoot flames and billow smoke when the commuter wear gets bad. They will still run doing that though! I got about 10-20 hours before mine went. I tried powering one with a 3,000 rpm ac motor but that speed wasn't enough to do anything. Another possibility if you hate universal motors like me is an ac centrifugal sump pump. They don't have the pressure of positive displacement but you can daisy chain them, the outlet of the first plumbed to the inlet of the 2nd, etc.. The first stage nearly doubles pressure and you can add multiple pumps.

[@StreuB1]

I've used venturi vacuum generators like this all my life for vacuum bagging composites to degassing solid propellants, vacuum molding, etc. Vacuum Forming tip; use a portable air tank for inflating tires to act as a vacuum surge tank for the initial surge to pull the vacuform material into the mold then the venturi will pull it the rest of the way into the mold. Works amazingly well for doing polycarbonate and PVC molding in the garage. :-)

[@IvorMektin1701]

Thanks for the tips!

[@NurdRage]

yeah, it's so simple yet so effective. Since a machine shop almost always has a source of compressed air, the venturi pump is an extremely cost effective moderate vacuum system.

[@StreuB1]

Indeed. Actually, the venturi generators that McMaster Carr sells generate huge amounts of vacuum (thought with air as the medium). During some destructive failure mode testing I did back in 2007. I was able to collapse a stainless steel case made of 3mm material measuring 400mmWx500mmHx1000mmL with one of those generators. Blew my mind.

[@NurdRage]

Did you actually measure the vacuum pressure? Because even moderate pressure can bend steel. What's doing the work is the surface area of the steel since pressure is a "per unit area" effect. Ultra high vacuum and moderate vacuum actually has very little difference in terms of mechanical effects since the force applied per unit area isn't very different. But ultra high vacuum is necessary for physics work because it's the molecules themselves that are affecting the results rather the physical forces they are applying. Hooking up a particle physics grade ion pump and a water based aspirator pump to a vacuum forming machine would show little if any noticeable difference. But hook those up to a mass spectrometer and the spectrometer would likely arc and destroy itself on the aspirator pump.

[@theodionne9370]

I can just feel my gear acquisition syndrome kicking in!😉

[@imikla]

+Nurdrage This is (according to auctions I have found) available in aluminum, copper, and stainless steel, all for around $10. My knee-jerk reaction is to get stainless, but I've learned watching your videos that metals don't always behave like I expect, so I wonder which is really the best choice. I also wonder if there is any benefit to getting all three and using different metals depending on what it will be used for, or if it would just be better to get three of the same kind (which ever that would be) so I have replacements when they corrode.

[@ExStaticBass]

I've done this sort of thing before with a similar setup. It never occurred to me though, to use ice water. It makes a lot of sense now that I'm thinking about it. Thanks for the tip...

[@berni8k]

Wow i had no idea this simple principle is capable of making a vacuum this good.

[@screenflicker1]

what you made is a scrubber. In the plant i work at it works using the same principle. It uses a venturi and caustic solution that pumps through the venturi. It generates just enough vacumm for all the reactor vents in the plant to allow gases to route to the scrubber.

[@NurdRage]

It can certainly be used for scrubbing. It's a very old technology and i think even the greeks had it thousands of years ago. In this context it's an aspirator vacuum pump.

[@screenflicker1]

Thanks for the response!

[@musketiers9]

What adapter is used on the pump to connect the threadings of the aspirator to the pump??

[@Oli-jm9fc]

Very nice work. I always used a refridgerator compressor as cheap vacuum pump in the past, I had one that could go down to 30 mmHg and that baby took solvent and corrosive vapours for years before it finally broke down. A fan on it was sufficient cooling so it could run relatively stable for 12 hours. It was free from a junkyard. I must admit that I've had others too that were not nearly that quality. You can also put two in series for a higher vacuum (or in parallel if you need a high flow rate, as they don't perform well there). I didn't use aspirators because of the waste of tap water, but I have to say your system is quite nifty, I like it very much. EDIT: I just tested an old fridge compressor in my garage and it measured +- 60 mmHg. I guess I was lucky with my late baby child (may she rest in peace) and there is considerable variation in vacuum strength in refridgeration compressors. This one came from a cheap fridge, maybe the ones from combo fridge/freezers or those big ass American fridges or store-type deep freezers are the ones to look out for here.

[@cibernerd]

With such a low vacuum, how come the flask walls don't collapse (implode or something)? Is there a risk of something like this happening? Thanks, for me this video was like a epiphany !

[@al_kaloid]

Please DON'T use regular Erlenmeyer flasks for this. I don't know why this didn't bother me back when the video was released, but this is definitely not proper lab practice. As you stated already cylindrical/conical lab ware isn't suitable for vacuum applications due to the risk of implosion. Always use RBF (round-bottom flasks) or flasks intended for vacuum use (heavy duty suction flasks are fine).

[@cibernerd]

@@al_kaloid Thanks so much for your great advice, i plan to try some experimental work with a somewhat similar arrangement, however i was guessing that since the vacuum was generated using a 60 watt pump then power was not enough to create a force to cause implosion, do you think this is right? Sorry to bother, is just that i have no experience with vacuum and just want to be cautious. Thanks !

[@Ubya_]

thank you very much NurdRage, i'm building a diy fume hood and the vacuum line was a big deal, i have a 1 stage vacuum pump (for changing refrigerant in refrigerators) but water vapour is a big no for this kind of pumps ( acids and solvents are even bigger nope). many amateur chemists use the venturi pump, but as you said, using it from the tap is really a waste of water, but this setup really saved me :D

[@Wunderbred66]

This is a great tool for the home chemist. Ultimately a refrigeration vac pump is best, they can pull to 500 microns as is standard for system evacuation, they are also acid resistant since refrigerants tend to produce acids.

[@pazgomenskii5310]

Please sir, what Hp (horsepower) refrigeration vacuum pump are you recommending here and how are they compared to A/C vac pump in-terms of power & chemical resistance?

[@JoshStLouis314]

Vacuum pump oil is pretty cheap by the gallon if purchased at stores selling farm products. They sell in 1 gal increments. Not great for high vacuum purposes, but if you need to change the oil frequently like me due to contamination, it is great.

[@djdrack4681]

So, For the dedicated amateur I'm thinking incorp a tall minifrig setup for keeping the aspirator water cooled would be +1. Either have the aspriator pump and container all in the minifrig and run a vapor/gas release hose out the side of the frig (in case any volatile gases leeching into the aspirator need to escape from inside of the frig; or run the aspirator/container outside and basically make an DIY closed loop cooler with an aluminum radiator the container sits on, then run the intake line through your frig (almost like some extreme wort chiller setups, but with hosing and not copper piping ofc), so it is chilled before reaching the aspirator

[@muh1h1]

You could also direct the waterflow from the pump through your destiller first, in order to save some more water :) Also you could add icecubes to the mix to keep it very cold! EDIT: Oh, seams like you did exactly that :)

[@NurdRage]

I actually had two separate water circuits. As said the video i strongly recommend against pumping the contaminated through your condenser.

[@gentiligiuliano7882]

Seems a reasonably good setup for my vacuum distillation of essential oils,. Also to distill out alcohol from tinctures without rising too much the temperature and destroing essential oils.

[@ronjohnson8126]

Hobbyist here, how well do erlenmeyers withstand a vacuum? I've always read that they shouldn't be used in vacuum setups because they easily implode. Have you ever experienced this? Do you think my cheap Chinese eBay ones would be safe to use? Thank you

[@guzman1810]

Thank you very much I did not know this method and it was very good for me to concentrate sulfuric acid since I do not have an airtight container that can be heated greetings from Argentina

[@megabeep8460]

hey what is that brass thingey you used to couple the aspirator to the pump

[@acrakatau4365]

Very neat (and cheap) solution, I didn't thought such a little water pump could handle a aspirator. To the cheap china rotary pumps: Yes they corrode extremely easily, but for the price of 50 bucks they are quite OK. Used one for many years, even Trichloracetic acid got in it an one point and the corrosion stopped the pump. After a little cleaning the pump was running again... (of course vacuum was not as good as stated, but for chemistry use it was OK with about 1-5mbar even after abusing )

[@Kloashut]

Idd a great and relatively cheap tool to achieve vacuum. Good that you explain not to connect it to your faucet and thereby spill loads of water while polluting it. We used them in our lab till around the mid 90's, then they got banned. Now its all membrane pumps, good ones are pricey though.

[@Lord_Pasta]

Hi, have you ever considered for even lower pressure to use a salt water bath with plenty of ice at below 0C. Anyway thanks for the vids

[@ThePharphis]

Very useful information. I wish I was taught this in my chem undergrad

[@Madarpok]

If you can get you hands on some thrown out fridges or air conditioners, you could use the compressor as a vacuum pump, a number of people have had success with them. Of course they are oil filled, and corrosive chemicals destroy them, but if you use a dessicant or appropriate adsorbent traps(activated charcoal is reasonable for organics, molecular sieves for water) they can last for a while. And often you can get compressors for free, if you salvage them from non-functional units.

[@NurdRage]

Sounds awesome! maybe i'll give them a go in the future if the channel is still around.

[@TheGuerrCZ]

Can you add salt to the ice-water to make it even colder?

[@Ta2dwitetrash]

Freezing bags of water. Thank you for that tidbit! That will be handy

[@karolus28]

just don't try to freeze 1L of warm water or your freezer will melt, I learned it the hard way

[@leeedwards3783]

Amazing. I want to try and make this for reducing juices and sauces etc. Thanks for the tip

[@trcostan]

I have been trying to freeze dry food I'm going to try one of these to get must of the water vapor and atmosphere out. Then switch to my standard rotary vane pump with a poor mans cold trap using ethanol and dry ice to get rid of what's left. The other option is to lightly add heat to the food. Will see what works I order one of these pumps

[@NurdRage]

Sounds awesome!

[@waynoswaynos]

That's awesome. So if a 100psi pump can make 30mbar or 56mmHg, I wonder how well a fishtank pump will do? I am happy with enough vacuum to stop acid vapours from escaping.

[@consciousenergies]

There is great power in potentiality isn't there? Very inspiring and great video as always.

[@K0ester]

I bought one after seeing this video years ago. Its never worked great. It sits in my random accessories bin years later. Ran across this video today. I might have to try it out again

[@HotboiEngineering]

Glycol is super cheap, just get concentrated engine coolant. Heck you could also get the 50/50 mix of coolant and water and use a plastic baggie filled with dry ice as the glycol coolant will drop the freezing point by a very very good amount.

[@marcoahernandezgarcia4819]

Hi! You have taught me a lot through your videos NurdRage. Thanks a lot! The pump you're using, does it withstand continuous work during all the distillation run? Or does it need to be stopped periodically to cool or prevent wear on the diaphragm? I suppose using ice water helps it to run cooler but, does it need break intervals? Thank you and have a nice day!

[@Andrew-my1cp]

1:25 the venturi effect is also why carburetors work. Instead of gas, it pulls through gasoline and vaporizes it.

[@Anonymous_404_Not_Found]

Would you have to worry about rupturing glassware with this setup? Or will it not reach that extreme of a vacuum? 19°C is over 29 inHg, for a 50$ setup that is ridiculously good!

[@NurdRage]

oh yes, glassware implosion can be a problem. Wear safety gear and eye protection

[@Anonymous_404_Not_Found]

+NurdRage I guess in theory the vacuum shouldn't be turned on until you close the fume hood. But if you're working with chemicals, safety goggles are a given anyways XD

[@SlyTy98]

I probably wont need this at any point in my life, but knowing how to create a vacuum using cheap parts may come in handy.

[@sandokannoname5738]

Que grande eres !!!!! I don´t know how to translate this but it feels so good watching this video....( and the one you made before it, and the one you made after, and the following......and the videos of the last year......... Thank you very much!!!!!!!!

[@RedDogForge]

is this a reccomended method for dustilling sulfuric and nitric acids?

[@GoldplatedDeagle]

We use that type of vacuum pump where I work, we fill gallon and half gallon bottles with milk and we get foam in the large stainless bowl so we use it to suck the foam off

[@jimparsons6803]

Nifty. Seen such setups before. Some that had their aspirators made from HD PP? Something like that. I think that you are right about buying the parts online, Amazon and eBay? Thanks for the demo.

[@SjwNz08]

Thanks for the video, about 10yrears ago I was trying to concentrate H2O2 from 50% to around 80% with a home made aspirator pump. But at the time I was just using water from the tap so was limited in pressure. So I might have to try this again with your setup.

[@GiGaHarrySfotter]

Hi Nurdrage, maybe if you remove the one way valve you can gain 20-30 torrs. Just make sure to disconnect the vacuum tube prior to disengage the pump. ciao

[@BeeRich33]

Had these in our lab in highschool 35 years ago. In fact im here to get one of these. And to hook it up to my hose.

[@cranebeg]

What is the connector size needed from aspirator to water pump? I'd like to know the thread type please, thanks.

[@johncollinspianomusic]

yes same I am not seeing mention of this detail in the video - am I missing it, @NurdRage? it looks like you have some brass adapter connected on the outflow of the water pump - what is this?

[@137bob3d]

this vid' is exactly what i needed. esp' the part about using a tub & pump to re-circulate the water. my need is to reduce the amount of water in an acidic plant extraction. as well as other distillations of solvents to recover the extra solvent beyond what was needed to dissolve the cd's of interest. i've known of you for several years now. and held off being a patron for a lack of see you using a spectrophotometer to monitor an experiments progress. as well as to show us how one can be used to determine distribution-coefficients of liq-liq extractions. and now , never mind all that, you deserve my support anyway. the next step ... reach for my wallet

[@Zorbeltuss]

My first thought when mentioning a low vapor pressure working fluid was mercury, my second thought was no, not mercury.

[@NurdRage]

There is something called a "mercury diffusion pump" which does take advantage of mercury's low pressure. But it works on a totally different principle to the aspirator pump.

[@kenny.aviation7645]

Why is that's a bad idea?

[@Zorbeltuss]

Many reasons, aspirator pumps made in aluminium will be soluble in mercury, many salts and oils will react with mercury, you will need to keep your mercury clean to prevent clogging and it will be an unnecessary level of toxicity when you think of the cost of buying enough mercury for the job since you could go for another more expensive vacuum pump. Also note, mercury is toxic but it's generally more toxic when it is mixed with other chemicals.

[@alexandre..9343]

@nurdrage dumb question, but is it ok to heat the system to increase the vapour pressure in order to push the stuck water through? Also you said nothing about how to control the vaccum within this system. Turning the vaccum off? Bleeding the system? I would appreciate any help/response.

[@adrianosalvian]

Thank you very much. I buy this system like yours for fractional distillation. Very cheap!

[@HoverFreddy]

I've just find out your same ProPump on Ebay,as soon as I can manage to get a glass venturi pump I'll use your same setup;if I can manage to make the device a bit more smaller for save space I'll upload a demonstration :-)

[@Fjallafarari]

Nice video. Do you know how much faster water will evaporate if: 1: You leave one jar of 10 cm of water in atmospheric pressure at 10 degrees centigrade 2: You leave one jar of 10 cm of water in vacuum with your setum (aspirator pump running water at 10 degrees centigrade) at 10 degrees centigrade?

[@chickenvsbigdog]

That is honestly brilliant.

[@jtbmetaldesigns]

You can use this for vacuum desiccation as well? Also, you mention this can break azeotropes. I was hoping to distill 72% perchloric acid without creating the anhydrous acid considering that the anhydrous acid comes over yellow from dissolved chlorine dioxide and I prefer to not do that..

[@ryanbrown006]

Can someone help me troubleshoot my setup. I have a similar pump (80 psi and 4.5 L/min) and a different aspirator however it appears to be only pulling a weak vacuum. About 700 mmhg (absolute pressure).

[@GNP3WP3W]

Same thing here my dude. I bought the same pump and aspirator as nurdrage and Nill. So, I bought a slightly better diaphragm pump 70W 6lpm .9MPa still nothing. So, I bought a heavy duty aspirator, the kind you fit on a faucet. Couldn't pull s**t. Honestly I’m pretty peaved at nurdrage for posting this fallacious trash.

[@Anar10n]

Either his pump is very different or vid is fake for views(chemists like to exaggerate yields and such for some wierd reason) You can get ~550-600 mmHg succ force from wall water supply tho Also make sure outgoing end of the aspirator is submerged at least at the begging

[@jhyland87]

I actually almost got the exact same aspirator vacuum pump that you got (Yantra Lab I think?) Looks identical to the one from Deschem, except it's not stainless steel (which I can tell yours isn't from the texture). Apparently these ones get destroyed from any corrosive fumes relatively quickly (say for example - using it to vacuum filter or distill something with HCl). The one I purchased is nickel coated, which apparently is even better than stainless steel. But I plan on setting up a self contained system just like you demonstrated here. Great setup!

[@31946mar]

I too have identical venturi but cannot get it to do better than -6 in Hg. Any suggestions. Pump looks just like his but is rated 70 W and 6 L / min.

[@jhyland87]

@31946mar I think just using really cold water at a fast rate... not sure what else to do that's practical and helpful. I eventually just found some amazing KNF diaphragm vacuum pumps on GovDeals. If you need a decent vacuum then I recommend you do the same.

[@31946mar]

Two things will make it work: 8" tail tube and city water. Never could do any good with pump like one he shows.

[@goodfeller2]

One more thing. Do you know anything about Al/Ga reduction reactions?If so, Could you make a video on Aluminum/Gallium reductions. I just recently learned about them and would love to know more and see how well they work. That would save so many hazards over the Al/Hg methods and, save a ton of money and accessibility headaches over the LiAlH4/NaBH4 methods. Thanks!

[@markbell9742]

Thanks: I wondered about the relationship between pump water temp and vacuum, but never looked into it. Cheers, Mark ************************************

[@tronictitan]

+NurdRage can u explain a bit on why the water is getting collected at the adapter? is the water going to the aspirator pump?

[@mattgrubbs]

Can you please tell us where you purchased a $6 nylon diaphragm pump? I looked through your previous videos and could not find reference to it.

[@rubenganesh2817]

what kind of connector (with size etc) did you use to connect to pump and the aspirator, because i cant seem to find one. can someone help me i bought the aspirator and pump from aliexpress but cant find a connector

[@CYXXYC]

lol would love water boiling in container from heat of my hands

[@generalingwer4341]

I found this very helpful.thanku.

[@nikschreiner6182]

Thanks for your content.

[@NolanPeard]

Perhaps finding a suitable solute to dissolve in the aspirator water would lower the vapor pressure suitably (and indefinitely, compared to using ice).

[@NurdRage]

No solute i know of can compete with ice. The change in vapor pressure is just too good. Also, since you regularly have to dump out the contaminated working fluid. You're also tossing out the solute too. So rather than an indefinite solution. that becomes an indefinite cost! Ice, has a FAR lower cost. For the cost of a few kilograms of salt (for example) you can have hundreds of kilograms worth of ice for the equivalent electricity cost. Solutes better than salt cost much greater and thousands of times more than the equivalent performance of ice. I like that you're thinking. In this case the numbers go against you but you have the right idea.

[@ethanmye-rs]

To be fair, a cold trap is easily set up. Most use a two stage design, one to cool going from ambient to a few below zero, while the next stage drops much farther. They are coupled by a heat exchanger. Normal compressors can be used, just gotta swap out the refrigerants. AppliedScience had a video on fixing his.

[@NurdRage]

Really? I was under the impression it would be greater than a few hundred dollars. how much does it cost? I could never find anything cheaper. Could you give me a link to where i can buy one?

[@acrakatau4365]

They normally are very expensive and hard to get. An easy and cheap way would be using a "dry ice maker" with a CO2-Cylinder, so you can always make a little bit of your own dry ice for the cold trap.

[@NurdRage]

+Acrakatau oh i've seen those. They're very expensive in terms of CO2 consumed. So the cost of cylinders will get you.

[@NurdRage]

+Ethan M Oh i already know about that device. The thing is they cost several hundred to thousands of dollars. So really a cold trap isn't all that easy for the amateur. I thought you had a way of getting them for less than a couple of hundred when you said "To be fair, a cold trap is easily set up."

[@UnauthorizedExpression]

This is amazing. I'll feel like an idiot for never considering this method of distilling water with safe non dangerous methods like by the heat of the sun. The problem has always been that you need high heat from a fire or very concentrated head from the sun using a Fresnel lens. Not common enough of an item and not available to ppl who drink toxic water because they can not afford to filter it. This method could very easily be converted to work off nothing but a river or streams natural movement. Even the oceans waves could be used to effect a pump I imagine. In the US we don't have much need of this, but I imagine a time when we will all need to distill our drinking water.

[@rttr5777]

+NurdRage why your old videos used to have an underlying title of professionalism but rather now they are DIY's and amatuerish ,and i don't mean any disregards i am a two year.old subscriber and i really appreciate your hard works Regards

[@NurdRage]

Ya think my synthesis of pyrimethamine is amatuerish? That's gotta be the hardest thing i've ever done.

[@rttr5777]

NurdRage what I really meant is the setup and lab not approaches and synthesis anyhow don't mind it much just a query from a fan :b

[@user-pn3fb9eo5i]

Thanks for the great video! I want to use this cheap vacuum set-up for ethanol, and it seems perfect for that, but I want to be able to distill at a temperature of my choosing (between say 35 - 50C with a rotary evaporator). So my question is: Can you vary the pump speed to give a certain vacuum, or do you always have to use the ultimate vacuum strength, (which is what you seem to do in the video)?

[@mytech6779]

I would like specific models and supplier if anybody has found a good aspirator at a reasonable price. (2021) I bought a $25us all metal water powered aspirator and it pulls a vacuum but not near enough to boil water near room temp and uses a lot of water. Just a lazy inefficient venturi shape. The check valve does work well. It has a less common 3/8 pipe thread so required multiple adapter pieces from the plumbing store to connect a garden hose(or even a common 1/2" pipe).

[@TheDabadu]

Hey Nurd, You say in the video (around 1:22), that the venturi effect is the cause of the pressure dropping. It got me thinking, an I came the conclusion, that that can not be true: The venturi effect (and the Bernoulli equation describing it) describes the pressure change INSIDE a perfect liquid. I can not imagine how your explenation should work... the liquid doesnt "absorb" more of the air around it because of the venturi effect (the opposit should be true (lower pressure --> less gas is soluble)). The venturi effect also only works with perfect liquids (not sticky). My assumtion why the pressure drops (and the german wikipedia page on it (it is longer than the english one) says the same) is, that because of small turbulences and friction, air is sucken away with the water (the high pressure and the Impuls conservation forces the air with the water)... I would love to get your point of view on it! Best regards, and keep up the good quality Dan (sry for the bad english)

[@sciencegadgetry]

I guess this will be my final comment on this. The Chinese "stainless steel" unit arrived today and looks identical to the one in the video. It was almost completely loose (and of course I tightened it) but while I was coupling one of the hoses to the vacuum side, the cheap epoxy/ thin rubber washer seal they used there gave way instantly. I reapplied the seal there with thread locker red. However, despite all efforts and using the same pump and set up as shown in the video, I am only pulling maybe 18" Hg. Unfortunately, I think this is the norm for these. The original eBay specs say it pulls a maximum of "420mmHg" so the maximum I am getting makes sense, but I can't figure out how the video maker is getting so much more with his. I'm giving up on this and going with a cheap electric vacuum pump. Single stage and metal, but I'm not doing acids so no worries. And the final cost really doesn't come out to much more than the set up featured here. The best results I had with a Kimax glass aspirator, but they are no longer available and used ones are running $50 US. Good luck to other folks who try this aspirator method, hope you fair a lot better than I did. I've been told that the metal units are going to need a LOT more water pressure than is provided by the small pump in the video. I believe this as the Humboldt units barely flinched with the pump and I had better results from the faucet. The necessary pump will run at least $60.

[@spaceminions]

I only got 15" with my setup using the metal ones and a similar pump.

[@manudehanoi]

I am pulling about 500 mmhg with the exact same setup. With a better (plastic) aspirator I get 700 mmHg. I got the exact same pump. Other pumps with similar labels have bullshit specs.

[@31946mar]

After many trials, hooked aspirator directly to outdoor spigot outflow nearest incoming house water. With this AND an 8" outflow hose, I almost instantly got -27.8 inches Hg so there is hope. Tried a more powerful 1/10 hp pump, twice what tried before, and got only -7 inches Hg.

[@31946mar]

Tried another 1/10 HP pump and this one die -13 in. Hg. Then the identical pump in the video and back to -6 in. Hg. Next tried my Aquatec RO pump that easily produces 100 PSI and it did - 7 in. Hg. Ordered a 1/2 horse power pump. Really would love to know if that is a magic connection you have from the pump to the aspirator.

[@BlueBeamProductions]

i will probably never do this but i still enjoy watching

[@brocktechnology]

I'm afraid I'm not clear on why the water starts collecting in the vacuum adapter. why doesn't gravity pull it through, air or no??

[@NurdRage]

surface tension

[@christophersteele9133]

Have you ever worked with mixtures of anhydrous transition metal chlorides? I'm trying to find more detailed information about their electrochemical/redox reactions with each other.

[@emilalmberg1096]

Amazing, you deliver once again, thank you sir!

[@cremationpete]

Very similar to what is often used for embalming

[@Mark12839447]

This is an awesome video, exactly what I was looking for; thanks a lot

[@crock5838]

great video learnt a lot thankyou!

[@antonellocalc]

Another very nice video! Thanks

[@chemprofmatt]

I'm wondering if it's possible to build individual fume hoods built on a similar concept.

[@TheCerberusInferno]

Excellent video thanks .

[@chibill_mc]

very interesting this might be a easy way to create the vacuum for my water based chiller project. I might end up machine my own instead of buying one but.

[@nucleochemist]

Using an expensive and annoyingly complex recirculating and refrigerated aspirator system I have been able to get down to about 20 millibar. The measurement of vacuum at this kind of pressure becomes difficult since water vapor interferes greatly with most vacuum gauges that can measure in that vacuum region. There are only very narrow advantages to this kind of system and I don't recommend it for any kind of typical lab scenario. That being said a simple "fit it to a tap/faucet" aspirator has its place in the lab, it's just that I've worked in a number of labs for many years and only ever seen one the entire time. So I stole it (from the basement) and now use it for convenient transferring waste water ^_^

[@NurdRage]

The advantage of the system in the video where I DO recommend it for a typical lab scenario is that it's cheap, chemically resistant, cheap, easy to clean and fix, cheap, not blatantly illegal since it doesn't dump contaminated water down the sink, cheap, doesn't need its own cold trap, cheap, good for most distillations except air/water sensitive ones... did i mention it was cheap? :) Every other vacuum system with better qualities in any direction costs another order of magnitude. While in a professional lab you would have the budget for it. in an amateur lab the aspirator pump definitely has its place.

[@waltersobchak7275]

NurdRage Yes it does and thank you for relaying other options/alternatives, sucn as this. It makes certain things, that were previously not feasible, now very possible, for us financially challenged individuals.

[@TheRedWon]

Color me impressed! Thank you for the video.

[@andresmaynez3060]

How did you connect it to the water pump?? I have the same setup but can´t find the connector

[@jeanpierredaviau7478]

Can we put sodium hydroxide in the water to neutralise the gasses? What are the possibilities?

[@NurdRage]

you can... but i don't reccomend it because the pump is made of aluminum, it would damage the pump. BUT you can instead install a "gas washing bottle" between the pump and your experiment, and put sodium hydroxide solution in that to accomplish the same thing.

[@joshuatanase3718]

How are you supposed to safely remove the vacuum once done and let the air back in slowly? Also, when you turn off the pump, is it possible for the water to rush into the receiving flask?

[@31946mar]

Look at the VEVOR vacuum pots which have shutoffs either side of a pressure gauge.

[@chang1865]

A very useful video, thanks!