# How to build a vacuum filtration system



## 4metals (Apr 10, 2009)

For those of you who need a good vacuum system, this PDF should get you started.


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## goldsilverpro (Apr 11, 2009)

A friend of mine set up a vacuum pump using an aspirator (eductor) and a sump pump that was set down into a reservoir of water. The water was recirculated through the aspirator. It would run 2 or 3 buchner filters and worked very well. This is very similar to the setup in the pdf, expect the cost was much less - probably not over $100. A problem was that his water reservoir was only a 5 gallon bucket. After about an hour, the water got hot and the pump shut down. After dumping the hot water, putting in fresh cool water, and hitting the reset button, it was up and running again. A 55 gallon reservoir would have been much better.

Not all aspirators work with all sump pumps. They have to be matched, based on the head of the pump.


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## Lou (Apr 11, 2009)

What GSP said is the truth. I learned the hard way that if you didn't have enough water to deal with the heat, your pump would shut down. You also have to make provisions to cool the water as it reciculates--the hotter it gets, the less effective it will be at making a vacuum as water's vapour pressure rises. I bought a pump at ACE for $120 and use it with half inch tygon which goes to the aspirator.


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## 4metals (Apr 11, 2009)

The aspirators are fine with small pumps and they work on small lots. The unit I described can run for an 8 hour day and filter 3 or 4 jugs all day. While I never put a vacuum gauge on the system to see how much vacuum was actually achieved, I can tell you that if you put your hand over the mouth of a 5 gallon vacuum jug on this system you can actually lift the jug off the floor within a few seconds of putting your hand on the jug. And it wont fall off. Although this pump and eductor is pricey, I can tell you that if you're refining karat gold the gold concentration is high enough in the acid that you want to be able to rinse completely and (if you've got workers you're paying to do it) quickly. This system will accomplish that goal. As you both have mentioned on other posts if you're looking for high purity metals good rinsing is important. McMaster Carr lists other eductors in PVC for smaller pumps so this entire system could be scaled down to save cash. Their entire catalog is on line, search their site for eductors to find the listings.


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## DNIndustry (Apr 28, 2009)

Vacuum aspriators are more for distilation purposes. They release the water vapor sucked in via a tray or dish.

A rotary vane oil based pump is over kill for a lot of people, should really have a manifold, flow regulator and a vacuum gauge

A good diaphram pump you can leave on and attain full vaccumm and not worry about glass ware imploding.


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## golddie (Feb 5, 2011)

why isnt the attachment not there anymore


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## Barren Realms 007 (Feb 5, 2011)

Probably the link needs to be fixed since the server host for the forum has been changed.


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## Sucho (Feb 5, 2011)

i am a little bit affraid of imploding my vacuum filter flask. i have LAVAT single chamber rotary vacuum pump, 1.5 m3/h , cut-off presure - 10 kPa.
is an implosion of my flask possible with this vacuum pump or i dont have to worry ?


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## golddie (Feb 5, 2011)

It would be nice if someone could fix this link so we can download the pdf
Thanks


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## lazersteve (Feb 5, 2011)

You guys sure are a demanding bunch.  

The old pdf is gone, but I have a copy:

Vacuum Filtration System

This one won't disappear.

Steve


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## golddie (Feb 6, 2011)

Hi Steve
Thanks for that link


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## niteliteone (Jan 11, 2012)

lazersteve said:


> You guys sure are a demanding bunch.
> 
> The old pdf is gone, but I have a copy:
> 
> ...



Thanks for the link Steve

Tom C.


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## chemist_12 (Feb 5, 2012)

Any glassware that is put under vacuum should be taped all around (on the outside) with good strong tape in a criss-cross or lattice fashion. That way if your glassware does implode at some point, the glass won't go flying everywhere.


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