Vacuum siphoning device possible?

[autumnwillow]

Is it possible to make a siphon device with the assistance of a vacuum pump without the liquid getting in contact with the vacuum pump?

This will be very useful for siphoning acids out of large containers since they tend to spill when you tilt them.

I've tried the idea of making one, a simple pvc tube with a faucet in the middle, the faucet is where the liquid should fall out, it didn't work. Heh.

 

[Palladium]

Yes it's possible with a flask, stopper, and some tubing. If you watch my YouTube videos on silver refining you will see how mine is made.

 

[goldsilverpro]

When I had my last refinery, I siphoned at least 10 times a day, usually from buckets, but occasionally from beakers or drums. I never used more than a length of clear vinyl tubing. The length and diameter of the tubing I used depended on how large of a vessel I was siphoning from. The trick of siphoning is to get the siphon started without disturbing the settled solids. Most siphoning gadgets I've tried tend to disturb the solids but just a length of tubing doesn't disturb them in the least.

Unless the solids are quite heavy and settle 100% quite quickly, I don't rinse by decantation. I've always thought that decanting a n rinsing multiple times from the beaker was a very inefficient method of rinsing, compared with filtration. It's a matter of the math.

My method (usually done at the end of the day) is to first put the bucket so it is about about 3 feet high, usually at the front of the bench inside a fume hood. I then stir the contents of the bucket and immediately place a short 2X4 underneath the back of the bucket - this tilts the bucket towards me. I let the solids settle o'nite. The tilt allows me to see in the bucket better and it makes the solids settle in the front of the bucket. I then siphon the solution off the solids into another bucket below. Often the settled solution is not perfectly clear, but that's usually OK. I then filter the siphoned solution until it's crystal clear and, when it's all drained through the funnel, I add all the solids to the same filter. In most situations, this ends up much faster and efficient than trying to filter the solution without first settling and siphoning it.

I've tried to explain my siphoning technique several times on the forum, using just words. One of these days, I'll maybe do a video, which would be much better..

 

[UncleBenBen]

I've tried to explain my siphoning technique several times on the forum, using just words. One of these days, I'll maybe do a video, which would be much better..

Now that would be popular video!!

 

[Topher_osAUrus]

Gsp, your words give a good picture.

Besides vinyl tubing, i found a nice siphoning system for sale at my local "brew your own beer" place, it cost me 10$ and it has lasted me a year now with no trouble.

Its basically a tube inside a tube that has a seal, and when you pull one out, then push it back down, up comes the liquid.
It ends up sitting perfectly on the bottom and does not disturb the solids, as the intake holes are not on the bottom but on the side about a half inch from the bottom.

Works perfectly, and I havent had trouble with settled solids following the mother liquor.

 

[goldsilverpro]

Gsp, your words give a good picture.

Besides vinyl tubing, i found a nice siphoning system for sale at my local "brew your own beer" place, it cost me 10$ and it has lasted me a year now with no trouble.

Its basically a tube inside a tube that has a seal, and when you pull one out, then push it back down, up comes the liquid.
It ends up sitting perfectly on the bottom and does not disturb the solids, as the intake holes are not on the bottom but on the side about a half inch from the bottom.

Works perfectly, and I havent had trouble with settled solids following the mother liquor.

When I was running x-ray film, I had 6 or 7, 55 gal plastic drums, with the tops cut out, sitting on a a strong steel stand about 7' high. Each drum had a bulkhead adapter about 1-1/2" - 2" from the bottom with a valve and a hose connect sticking out. Before going home, I would pump the 300, or so, gallons of solution plus film sludge into the drums. The next morning, all the sludge had settled below the bulkheads. I attached hoses to the 6 or 7 hose connects and drained the solutions back into the tank, leaving the sludge in the drums.

 

[Topher_osAUrus]

Hah, its uncanny how similar the setup I am making is going to be to that.

Except, the only differences are going to be my framing is going to be wood. And I will be using 5 gallon buckets, except when it comes time to cement out with iron in the stockpot, then I will be using a 55gallon drum.

I also thought of putting in a lever on the top level that can change the pitch of the buckets, so that i can get all of the settled solids to the nearest corner. ..sometimes a 2x4 alone doesn't get them all to the front and there is a thin layer leading up to the back side. The only dilemma I have thought of with a variable pitch on the top level, is I wont be able to use pvc as easily to connect the top level bulkhead to the top of the bottom buckets... But, I will think of something.

I will post a picture of my drawing as soon as I get back home.
Thanks for the reply gsp, you have given me more ideas to work with, I truly appreciate it.

Edit spelling

 

[4metals]

I believe a production refining environment is more productive and safer when using vacuum to transfer chemicals. This can be as simple as transferring chemicals from bulk containers in small quantities up to some of the systems I will show for the things refiners use daily which can benefit from the safer handling.

The heart of the system is a vacuum. I prefer a venturi eductor to generate the vacuum because they last. It can be as simple as hooking up a length of heavy rubber vacuum tubing to a 4 liter Erlenmeyer flask which is used to receive the liquid you are transferring. The vacuum tubing connects to the spud on the side and a solid rubber stopper that fits the top opening is modified by adding two holes. I prefer 1/2" holes (a Forstner woodworking bit drills nice holes in solid rubber stoppers) In each hole I insert a 3" length of 1/2" CPVC pipe (the copper pipe size is 1/2" OD and fits the hole perfectly and snug.) A length of tubing is slid over one of the stubs and clamped on and on the other end of the hose (which for most members use should be about 4 feet) clamp an 18" length of the same 1/2" CPVC pipe. The second 3" length of pipe is simply a vent.

To use the setup, attach the vacuum tubing to the flask and place the modified stopper with the hose in the top of the flask snugly. Place the end of the long length of CPVC pipe in the solution you wish to transfer. The vacuum pump can be on now because there will be no transferring of solution because the second pipe is open to atmosphere and no vacuum will be generated for the transfer. When you want to begin transfer simply place a finger over the open section of pipe in the stopper and the vacuum will build up in the flask and the flow will start. Simply lifting your finger will drop the vacuum and the flow stops immediately. Very safe. Please don't be tempted to eliminate the vent pipe and unplug the stopper, the open pipe finger combination is simple and quite effective. Please remember always that the tubing from the chemical can still have residual chemicals in and on it, so exercise caution. We can make it easier to move liquids but we cannot eliminate the need for safety when using the chemicals.

I have also set up refiners with acid on tap using a similar setup to fill 5 gallon glass jugs with Nitric acid or Hydrochloric acid. This is the setup for acid on tap.


The tubing feeding in through the top connects to a drum of acid either next to the hood or in another room. The tubing in the side of the neck is the connection to the vacuum. The spigot on the bottom is the acid on tap. The gray PVC pipe is connected to a vacuum manifold. The hose connection to the right is where a length of vacuum tubing is attached for vacuum filtration, the valve in the tee riser is to turn on vacuum to the acid jug. The tee above the valve is a vent. It is simply a cap on the pipe with a 3/8" hole drilled in it where you put your finger. When your finger is over the hole, the acid feeds into the jug and you won't be tempted to walk away (as one client did before I added the vent hole) because when you remove your finger the suction stops. Once you have had acid on tap, you will never go back!

I also have a system of mounted vacuum receivers for transferring of acid for filtering or any refining related solution transfer application. They are more complicated as they have built in rinse systems and high level shut offs. But if anyone is interested I will post some details and pictures as it is my design so it is mine to share.

 

[autumnwillow]

4metals design is what I had initially had in mind, I was willing to sacrifice my 4 litre filtering flasks for it but customizing it to a glass shop is expensive.

4metals if you are still using that rubber stopper in a acidic container it probably has degraded already. What I do is I wrap that rubber stopper with teflon tape before attaching the connecting tube to it. Lasts a lifetime I think.

 

[4metals]

The classic black rubber stoppers last a few years in the Hydrochloric but in the Nitric you need the Silicone rubber stoppers. So if you have to buy stoppers, buy them all silicone rubber. A #12 white silicone stopper costs less than $7.

 

[kurtak]

Here are some pics of my siphon set up

syringes with the tubes are for pulling solutions from smaller beakers - 1 marked with red tape for nitrate solutions the other marked with yellow tape for chloride solutions - with these I draw the solution to fill the syringe & then transfer to its receiving vessel ( Buchner filter funnel, clean beaker for precipitation, or waste bucket) they hold up relatively well - but eventually the rubber plunger gets sticky so needs replacing the syringe

The siphon hoses are sized (diameter & length) such that they draw just enough fluid to start the siphon BUT not draw any fluid into the syringe (keep the syringe siphon end "above" the level of the solution being syphoned) you can then pull the syringe from the hose (without concern of overflow/spill) then drop the output end down into the receiver vessel --- as long as you size the hose so that it doesn't draw solution into the syringe they will last a long time - I have been using the same syringes for 5 plus years now

When you pull the syringe from the output end the fluid in the hose is going to want to equalize "a bit" one way or the other --- sooo - be sure your out put end is high enough that it doesn't over shoot/spill out that end - and - don't put the siphon end all the way to the bottom of the siphon vessel - put it in just enough(1/3 - 1/2) to start the siphon - other wise any back flow will disturb the sediment on the bottom (practice with some water or waste solution to get the feel of this)

I always clamp the out put end of the hose to my receiver vessel & then I can re-adjust the siphon end down in the siphon vessel

Like GSP I also tilt my siphon vessels & I normally set something (tall & heavy) in front of the siphon vessel to insure it doesn't tip over (which I did not do in the demo pic)

I also color code my siphon hoses (with colored tape) red for nitrates, yellow for chlorides, white is "strictly" for silver nitrate & black for waste

And I use the syringes to wash/flush the hoses with D-water (usually 3 times)

The smaller of the 2 large syringes (for hose siphoning) is used for 5 gallon buckets & the larger one is used for 15 - 25 & 55 gallon drums - it works great on the 15 - 25 gal drums --- but will have a hard time on a 55 gal drum - IF - its not full & you are trying to pull from close to the bottom (it can take several tries) if its a full 55 drum just start it with the in put end high in the drum (the siphon will start with no problem) & then drop it (the in put end) once the siphon is going

Kurt

 

[everydayisalesson]

This is an awesome thread guys. I basically use the syringes the same as Kurt but I need to get some of the long white tubes. That looks like it is so much easier than holding tubing. I love your identification tape.

 

[Topher_osAUrus]

*Brilliant*

All of it...

..now I almost have too many choices to go off of.

I see the benefit in each of the ones posted by our resident professionals.

So, what are the drawbacks to each of these?

In my mind simpler is always better, as there is less to go wrong... But, that vaccuum siphon system 4metals posted is just plain awesome. ..

I would like to know though, what each of you dislike about your own systems... Like a pros and cons deal i suppose.
That way other new people can make a good objectionable decision as to what could be the best for them and their current lab setups..

...i think this thread is library material

 

[anachronism]

One of the hardest things for me is having to hold and move the tube in the solution without getting too low. I'm going to 3D print a mechanism to do that for me, and make fittings for different standard beaker and bucket sizes.

Edit: You could also utilise a peristaltic pump with variable speed as part of the system.

 

[4metals]

The only down side to acids on tap is the space it takes up in your hood. I have had 3' wide tabletop hoods made which were used entirely for acid dispensing. I even had one made up that was 5 foot wide for Nitric, Hydrochloric, and Sulfuric that an electroplater used. He was frustrated because of the cost of the drum pumps for acids (a different pump for each acid) which he said were constantly burned out by his platers. He also didn't like the fact that it was a pain to empty the hoses every time the pumps were used and the fact that where they usually dispensed the acid was rarely in a hood but rather in a bucket on the floor. (think stinky fumes!) These units are inside a vented hood.

 

[Roj]

Hello there . I just wanted to share this with you , it may be a help to you and everyone else here .
I found this to be very usefull , it Work perfect its plastic , you can buy it from Lows for 14 dollar .

 

[autumnwillow]

That will not last long for acids, trust me, had something similar before. It's usually made of cheap polyethylene plastic. Not sure.

 

[snoman701]

I just read that customizing it to a glass shop is expensive. I am having a vac trap repaired right now (barb broke off). $15 cash. Find the guy that works out of his garage!


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[snoman701]

Just a thought for nitric....beeswax has been used to make seals for nitric acid vessels for years! You can also get a good assortment of silicone caps, plugs & etc from your local powder coater. They use them to plug holes. I have not tested either of the above methods....so please be safe and test first.


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[g_axelsson]

Easy start for siphoning bulk liquid where a bit of extra water isn't a problem.

Take a piece of clear plastic hose. Fill it up under a water tap so there are no air bubbles inside, keeping the ends at the same level. Put your thumb over one end and place the tube between the buckets. Remove thumb and the liquid start to flow.

It adds a bit of water but works with a minimum hassle.

Göran