Choosing filter papers

[Tzoax]

Tzoax do you use a vacuum?

If you regularly get 2l and 3l and 4l solutions that need filtering then it surely would take forever without one?

Ahh thanks Sno

I don't use vacum pump, since i am processing small batches - i am replacing wet towels after about 2l of solution (that went through it). It is a slower than using filer papers but i am not in hurry. It all depends how tight you place wet towel inside of funnel. At first it is about 1 drop per second, after some time it gets slower. I leave it filtering 2l at morning and it is done by evening - then i replace wet towels.

 

[kernels]

Alex, I wish I had bought my buchner funnel and filter papers earlier. I spent a year doing it with a paper towel charmin plug and I only now appreciate the time that I wasted!

I harvested a vacuum pump out of an old desktop medical sterilizer, it was used to pump water and steam as well as draw a vacuum, so when I'm finished vacuuming solutions I tend to just run a cup of fresh water through it. Surviving so far.

I would say confidently that the filter papers I use combined with the vacuum buchner performs just as well as the paper towel charmin plug, but it takes seconds or minutes instead of hours or days. You can also change the filter paper in a few seconds if it gets clogged too badly.

I think the only place for charmin plugs for me now is when I use fiberglass to filter Sulfuric.

 

[Shark]

If I were running 1l and 2l at a time on a regular basis, I would have been after a better system a long time ago. I use charmin plugs a lot of times. (Here is a baby one for you Snoman) Today I was running 50ml of solution through a glass funnel with a charmin plug. It took 2 runs, about 4 hours in a funnel that is 2 1/2 inches wide. Watching paint dry would have been more entertaining (and probably faster).

 

[Palladium]

If your going to do GF on a regular basis get you a vacuum pump. You can get them off ebay for about $50-60 new. I have the first pump i ever started with out on the farm. I have sucked every kind of gas you could figure through it and it's still going strong. I run nothing but 10W-30 motor oil in all my pumps and they work great! I think the motor oil protects them from the gases better than pump oil does. I've had my pump run solid for 2 weeks at a time with no problem.

 

[anachronism]

If your going to do GF on a regular basis get you a vacuum pump. You can get them off ebay for about $50-60 new. I have the first pump i ever started with out on the farm. I have sucked every kind of gas you could figure through it and it's still going strong. I run nothing but 10W-30 motor oil in all my pumps and they work great! I think the motor oil protects them from the gases better than pump oil does. I've had my pump run solid for 2 weeks at a time with no problem.

Thanks that's a good tip.

 

[snoman701]

Agreed...I read Jon's post and thought, WOW...that's expensive! Thinking of changing out vacuum oil.

Although even a quart of 10w30 is up to 6 bucks these days.

I personally use a gast diaphragm pump. The diaphragm kit will cost me $100 when it fails, but thus far it's going strong. I got it from the scrap yard, and I have another three of them lined up to use when it fails.

 

[frank-20011]

hello,

As I read filters are intended for the milk processing are well suited. for filtering out small particles and for high liquid flow.

anyone tried them?

regards!

 

[Palladium]

Agreed...I read Jon's post and thought, WOW...that's expensive! Thinking of changing out vacuum oil.

Although even a quart of 10w30 is up to 6 bucks these days.

I personally use a gas diaphragm pump. The diaphragm kit will cost me $100 when it fails, but thus far it's going strong. I got it from the scrap yard, and I have another three of them lined up to use when it fails.

I use used motor oil that has been settled and filtered. It's the same used oil i use for my chainsaws.

 

[4metals]

It's the same used oil i use for my chainsaws.

As bar lubricant I assume, not in replacement of 2 cycle oil.

As far as vacuum goes, I switched to eductor systems years ago and never looked back. Minimal maintenance and no oil required. (It's all about my carbon footprint!)

As far as filter papers go, I like PCI scientific, the papers are reasonably priced and they have different speeds, as they call it. Medium speed PCI No. 613 is about $11 for a box of 100 circles of 11CM diameter. And Slow speed PCI No. 610 which is about $14 for a box of 100 circles of 11CM diameter. http://www.pciscientific.com/filterpaper.html

And don't forget to place a piece of plastic window screen smaller than the hole pattern in the funnel under the filter paper, it increases the speed and does not effect retention.

 

[Shark]

Since I already have a re-circulation system in use I am leaning towards an eductor system to get started. Maintenance is another factor for me right now as well. Given good vacuum lines will the pressure hold up over a distance? I would like to keep the system outside or in another room, and run the vacuum about 10 feet into the area where I would be working.

 

[4metals]

I have run eductor lines over 100 feet from the eductor/circulation circuit with no loss. What you need to do is use 1 1/2" or 2" PVC pipe from the eductor to the point where you use the suction. At the last minute I reduce to 1/2" for a valve and a fitting to adapt to rubber vacuum hose.

There are a few caveat's to this. First the large pipe acts as a vacuum reservoir so if it is too long and you have a little tiny eductor, (my condolences!) it takes a while to build up vacuum. I generally use 10 CFM eductors for a refinery. Second, and this is important, when you are recirculating water for a vacuum circuit the discharge of the recycled water needs to be deep in the recycled water tank. This keeps the vacuum from exceeding the eductor's ability to pull more air which, if the tube isn't submerged, causes the system to essentially burp and lose suction. But if you shut off the circulation, the vacuum reserved in the PVC pipe will suck itself full of the water in the recirc tank. So I always install a vent valve right by the eductor circulation tank which is closed when operating the vacuum but opened when you are shutting off the circulator to prevent the flooding. In shops that have the circulator and tank far from the refining area, we often set up a remote switch in the refinery for the pump as well as a normally open solenoid to act to vent the vacuum reservoir when the pump is shut down without having to walk over to the tank to shut it or start it and more importantly so you don't forget to vent.

 

[Shark]

Thanks 4metals, long term this sounds like where my thinking was going. I like the idea of having everything out side the initial work area as it leaves room for the actual refining equipment, but I wouldn't want to have to keep going outside on in the other room to turn things off and on.

 

[Topher_osAUrus]

There are a few caveat's to this. First the large pipe acts as a vacuum reservoir so if it is too long and you have a little tiny eductor, (my condolences!)

...It's like you are looking over my shoulder.

:lol: :lol:

 

[Shark]

So I've sent you some whatman 41, whatman 1, a glass fiber filter from sterlitech grade c-42 and some plastic screen to speed up the process. I cut my plastic screens to be about 1/2" smaller than the diameter of the holes on the buchner, but your filter paper has to seal to the porcelain at the edges, so you may need a little more.

Please report back on how you like them.

Unfortunately, they are all bigger than your buchner, so you'll have to pretend you are in kindergarten, get out the safety scissors and go to town. Take snack and naptime afterward.

Package arrived today, actually yesterday I just didn't get there in time. On the Whatman filters which ones are which? One is larger than the other.

 

[snoman701]

So I've sent you some whatman 41, whatman 1, a glass fiber filter from sterlitech grade c-42 and some plastic screen to speed up the process. I cut my plastic screens to be about 1/2" smaller than the diameter of the holes on the buchner, but your filter paper has to seal to the porcelain at the edges, so you may need a little more.

Please report back on how you like them.

Unfortunately, they are all bigger than your buchner, so you'll have to pretend you are in kindergarten, get out the safety scissors and go to town. Take snack and naptime afterward.

Package arrived today, actually yesterday I just didn't get there in time. On the Whatman filters which ones are which? One is larger than the other.

DOH

Big = #1
Little = #41

 

[Shark]

I finally had a chance to try my buchner funnel and some different filters. I ran a small lot of gold filled and just by watching it, it was obvious that it would a good test run. I used two coffee filters with a screen on the first one and as expected the quality was off some. On the second batch I used a #1 Whatman (Thanks to Snowman). The second lot was left with a clear solution on the first pass, while the second solution took another pass through dual coffee filters to clear up. Here is a picture of the two coffee filter solution after the first pass.



In all the excitement I forgot to take any more pictures.

While the filters didn't seal properly, and I know some trash slipped through there, the filters still lacked the ability of the Whatman filter (which did a better job of sealing off the edges as well). The single pass filtering ability made me pretty happy as it was, but considering that I cut what had been a 3 to 4 hour filtering job down to making three runs with the vacuum setup in 45 minutes I was very pleased with the results. I will be moving on to two runs of AR today instead of one, and will have completed two jobs at the same time (for another first for me).

For those who are curious, get yourself the buchner funnel and a vacuum system. Saves a lot of waiting, and with proper filters cuts down on multiply filtering of the same solutions. Having a system that could be turned on with the flip of a switch would (will) be great.

Thanks everyone for the input.

 

[Palladium]

While this may be true as to the ease of your filtering this is the exception and not the rule with GF.
As your lots get bigger and less segregated the amount of possible contaminates grows.

Tin
Al
Stainless
and Iron.

Not to mention any fillers or organic materials!

 

[Shark]

I am sure, as it grows there will be other problems arise. I have had a run in with iron, that was a bit worrisome :? but we got through it. For now though, it sure beats a regular funnel and coffee filters. If it gets to bad, I will have to pick your brain I guess, :lol:

 

[Palladium]

Wait til you chew thru your first large lot of high stainless!
It gets real exciting! Some go easy as pie. Others....... Not so much so.

 

[ARMCO]

Almost forgot,

Kernels I would like to know that as well. Also, what, if any difference it makes on the porosity of the filter or does it concern more of what the filter is made from?

I don’t know if somebody has answered this already. And it’s really only just a basic answer I’m not sure if it’s what you’re looking for.

My understanding is that qualitative keeps “the bad stuff out“ and will generally flow more readily.

Quantitative is more for when you want to be extremely exact about the amount that you have in the end.

So if you were just doing general refining and you want the clean filtrate qualitative should be just fine. If you’re doing extremely precise analysis and assaying, let’s say, then quantitative might be the way to go.

Now I’m speaking way “above my pay grade” so if somebody else has a clearer understanding or a better way to put this I certainly am not offended. Have at it.


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