Was thinking about this (or alike) little gems that produce an under-pressure:
It sucks 0.5 bar. 12 Volt, 7 Watt. Only 15 dollars, free shipping. Tempting!

Any ideas if this is a workable solution to vacuum filtration?
Thank you.

Ordered this one, sucks a tad more, same price 15 $.
Couldn't resist trying out


Will take a month to get here, will report how it goes.
Hopefully it satisfies but if not, no big deal for a price of one fat pizza.

That's a lot for one pizza
Lol, in NYC a large pie is like 10 bucks


Also, as for efficacy, it certainly couldn't hurt. Even if it's not a full vacuum, it might still be enough to have an effect.

It crossed my mind to put two of them in series to get more vacuum, for the price of 3 NYC pizza's. But will see first what one of these toys can do. They claim to displace 2 liter per minute, so after 1 minute it should suck a 2 liter bottle to it's max performance.

3 NYC pizzas? That's very clever though, I wouldn't have thought of linking them in series. Certainly let us know how it turns out; I know I'm going to be picking some up as well. Also, I think (2L/min)x2=4L/min should be just fine for purifying purposes. I imagine something like cannabis concentrates might require more immediate suction (or maybe not) compared to DMT crystals when trying to extract gaseous solvent from them. Also, if performed while the DMT is in liquid phase, I could see these pumps working great.

EDIT: So I just checked the specs on a vacuum distillation setup at my buddy's lab and they get the pressure at the top of the setup to 3Kpa, sometimes 5 or 6. So, if you're at sea level, 101 Kpa - 65Kpa = 36Kpa. So one device would not be sufficient for vacuum distillation, but two in series would likely work. I admittadly am unsure of my math

"Vacuum" is somewhat clouded by the freely usage of:

Absolute Pressure = pressure above real vacuum, cannot be negative
or
Relative Pressure = offset pressure against the surrounding atm, can be negative.

100kPa = 1 bar = sea level pressure:
So your buddy's 3kPa AP = 0.03 bar AP;
And the toys -65kPa RP should be 0.35 bar AP

I would not count on distillation damps of hydrocarbons with the toy pump, I guess it's all plastic inside, it might dissolve gradually.

Lets have some tech jibber jabber purge:
Without aid of a pump, just a funnel, what is the pressure difference top level to bottom?
Static height say 0.2 meter, gives 2 kPa only, then 50 to 65 kPa toy-pump aid should factor it +/- 25 to 30.
With full vacuum the factor is 50. So grossly the toy pumps will do half as fast as pro $$$ lab pumps. But the price difference is a cargo of NYC pizza's.

Working with two toy pumps:

* electrical side: 12V is a common standard so they must be put parallel;

* Pump side:
That would be so if they're put pneumatically parallel, but then only a small fraction will be added to the total vacuum performance.
Putting them pump sides in series, vacuum performance will add up and full vacuum should be theoretically possible. Yet flow rate of 2 liter per minute will only be increased with a (neglectable?) fraction.

For the sake of comparing: just measured my Dyson vacuum cleaner pulls -22kPa RP (leaves 78kPa AP). That is less than half of what the toy pump should pull. That is not much of a vacuum filtration feat, yet 10 times better than a funnel without vacuum aid.

Nice, I really wish I had the background to understand all of that, but I'm getting there. I'm still an undergrad taking gen chem courses (read: sophomore taking intro to chem) so I'll catch up eventually! That's neat about the Dyson though, so essentially any advancements in lowering the pressure are still better than nothing is what you're saying? If so, I'd be inclined to order some of those lil guys as well to toy around with.

Nice that you do the course, I hope you get trough it safe and sound

Don't get baffled easily, it's just numbers.
We're used to have a feel with Bar or PSI, then comes this exotic sounding kPa.
Yet it has an advantage, since 100kPa corresponds to 1 bar, we can use the kPa straight as % of bar. If we say that full vacuum is 100% of "driving force", then the numbers are:
Your buddy's lab vacuum pump: 97%
The toy pumps: 50 to 65%
The Dyson: 22%
A funnel of 0.2 meter height without pump: 2%

Did a vacuum filtration setup with the Dyson as a funny test case:
What was initially absolute non filterable by the funnel alone, the Dyson sucked with it's 22% driving force at a rate of 10 to 5 drops per second. So it did work out somewhat.

Draw back: the engine needed some constant air flow to cool down, something not possible in a filter setup. So I had to incorporate a slip air flow for this. At least this illustrates that 1 toy pumps with 50 to 65% should do the job

Wow! Thanks for the great explanation, that makes sense now. I'll definitely be giving vacuum filtration another more serious look now that it seems there are affordable hardware.

Another cheap way is an old fridge or freezer compressor, they suck really hard toward vacuum.
I had 2 of them before but hey are heavy and clumsy units. Used them for vacuum bagging molded parts during the hardening of the epoxy resins. I stopped doing that and got rid of them compressors. I know for sure they give plenty suck-power.
Just one thing to take into account: the exit tube will spit some oil which is normal, in a fridge setup that oil makes a tour and comes back into the compressor. If using it for vacuum pump, then the exit tube should be hung upward with a wide diameter tube, so that any oil can flow back down into the compressor after switching off.

I changed the title from the thread.

The pump is in-da-house and the first tests are done.
So I really aimed at the cheapest pump that draws 65% of vacuum at 15$ all in price.
Found it on the auction site under:
DC12V 65Kpa DC micro vacuum pump Pumping air pump 65Kpa Air sampling

It seems they increased price to an amazing 16.14$ meanwhile.


In picture attached below it shows to draw more than the promised 65%, it went 78% of vacuum, huray.


It comes with nothing on the poles as in the selling picture, but these little motors like to have some capacitor on the poles, so there's less of sparks forming on the brushes, sparks lead to heat lead to shorter life time or faster degradation of performance. It will no doubt work without, but I like to do things properly if possible for a buck.
Between the poles comes a 470nF 250V capacitor which does most of the job.

On the auction site they come as
4 pc - .47uf 250v (0.47uf, 470nf) NP axial capacitors FREE SHIPPING
Only 4$ all in price.


I did extra effort with 2 capacitors, 1 from each pole to the iron mass of the motor, this is really optional but takes away interference to surrounding.

On the auction site they come as
50pcs Monolithic Ceramic Chip Capacitor 0.047uF 47nF 473 50V
Only 1.42$ all in price.

All these capacitors have no polarity to respect.
Just take care the + from supply comes to the red dotted motor pole.

I had a mimo powder pulp that did not drip 1 drop, unless the pump was started and all liquid came trough wonderfully and clean.

Then I tried powdered rue, but this did not work, and I cannot imagine that even a full vacuum would be sufficient. Some drops came trough but it was to slow to let the motor run so long for it.

Give it 1 minute and it comes to its max vacuum in a 1 liter bottle.

So it worked, but the main question is how long it will keep up performance for that price of pump. We'll see. It makes a soft grumble sound, no high pitched RPM wining, thank god

Now as power supply: I used a heavy 12 V DC station for testing, but reason I choose for the 7Watt pump was to find a cheap supply too. I was hoping something convenient like this would work, but I have to test that later:

AC 100-240V To DC 12V 2A Adapter Plug Power Supply For 5050 3528 Strip LED
5$ all in price.

So that a total price of below 25$ adapter + pump was reachable.
Another advantage, this combo fits almost in your pocket.
And what if it keeps doing the job well for once a run in a month?

You could also use a hand pump (sucky as hell, but indeed works), or a water aspirator.

I still use an aspirator at times, in fact I'm building a venturi into my hydroponics system to cycle clean air through the room.

Yes, the alternatives are out there, and a search with "vacuum" give them, just wanted to cover these little toy buggers. It was mostly curiosity.

The thing is, it's not only a vacuum pump but also a gas transfer pump in general at the same time. Things like in picture below are on the list.

I've other ideas to do with it, if OK then I will update on that.

I got one of these:


It did not work
No idea why. Is it malfunctioning? This dirt-cheap makes me wondering about quality.
Being actually a LED-strip supply, does it not work in other combinations?
The adapter delivers 2 amps, and the pumps nominal current is 0.5 amp. So that should be fine, unless the startup-current of the pump has a current spike exceeding the adapters capacity and destroying it.

After the trial, with a digital volt meter I get nearly 2 volt at its poles.
I will come back later with news.

EDIT: they're going to resend a new for free.
A month waiting time is default.
This time, before attaching it to the pump I will check on the adapters functioning on its own. To be continued...

The friendly Chinese people send a new one for free.
And this one works like a charm!


So the first adapter was delivered malfunctioning.
Later we'll see how durable it all is, and if pump internals will be damaged by vapors of hydrocarbons or not.
A 75% vacuum setup in a hand palm for less than 20 dollars all-in, cute
I'd love to put a second pump in series (one adapter can feed 2 pumps) to get full vacuum just for the sake of it, but then again why if this works as well? And the pump must first show some endurance performance.

So that first failing adapter they send me (and replaced for free), I was still wondering if any possible non-compatability with the motor+capacitors could have destroyed it. If so then I might have just been lucky with the second adapter so far who should be waiting same fate sooner or later. I would not like to advice here a combination on the borders of failing.

Thus I opened the failing adapter (could be done without any damage to casing) to inspect. Fuse and leads were OK. Then the soldering side showed a failing soldering, right in the middle of the picture. That little "volcano" should have looked like the solderings above it. Soldered it nicely and now it's working like a charm.

Thus it was a internal hardware problem resolved.
For the rest it looked like a nice piece of product though, just madness how they could build and send it for the money.

Thank you for the idea.

Total cost for all the components was sligthly over 20€.
Works way better than I expected.

Hurray for the (lego)tinkerers

I'm still using the one from this thread, keeps working fine.

Now I've bought a more impressive looking pump/compressor (airbrush-comp), see attachment, on amazone for 70euro's.
But it does not suck harder than the good old little nifty one, so you're good