# 23 l plastic carboys for vacuum degassing/transfer



## rhattin (Nov 7, 2015)

Have a large number of plastic carboys ( Better Bottle and others) that would like to use for vacuum degassing, transferring and racking. 
Plastic is not strong enough by itself - carboy walls basically collapse at anything over 2 in of H20 vacuum and that is not enough to degass anything. Has anybody seen or got something to either add to the outside of the carboy or to the inside that will prevent this buckling? Or is this another opportunity for an invention?
Ric 
Wine Time Factory
Seabright


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## Runningwolf (Nov 7, 2015)

A vacuum pump will not work as you already know. I would suggest buying a small transfer pump.


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## ibglowin (Nov 7, 2015)

Hey Ric!

Good to see you online again! Might be time for an intervention, I mean invention! Some type of pop up spring loaded widget that would spring open and keep the walls from collapsing from the inside under vacuum should do the trick nicely. Find a way to make it spring open as you pull a vacuum and then collapse back when the vacuum is released would be even better.


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## rhattin (Dec 8, 2015)

*Plastic bottle vacuum degassing*

A little update about the latest craziness from my shop. My LHBS asked me to design and build a 3 carboy degasser using the plastic 23 l carboys. Went the big vacuum chamber route, with 3 inlet nozzles, a central vacuum draw and removeable top plate to allow "easy " ingress and egress of bottles. This sucker needs a lot fo vacuum to work, so I am toying with using a small shopvac for the central vacuum draw. Has anybody used a shop vac for transfer/degassing before. Seems to be a tradeoff between air moved and stall pressure. Control system still to be built. 
Ric
Wine Time Factory
PS Pictures in next installment.


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## sour_grapes (Dec 9, 2015)

rhattin said:


> A little update about the latest craziness from my shop. My LHBS asked me to design and build a 3 carboy degasser using the plastic 23 l carboys. Went the big vacuum chamber route, with 3 inlet nozzles, a central vacuum draw and removeable top plate to allow "easy " ingress and egress of bottles. This sucker needs a lot fo vacuum to work, so I am toying with using a small shopvac for the central vacuum draw. Has anybody used a shop vac for transfer/degassing before. Seems to be a tradeoff between air moved and stall pressure. Control system still to be built.
> Ric
> Wine Time Factory
> PS Pictures in next installment.



Your note confuses me. At first, I thought you were planning to try to solve the problem of collapsing plastic walls by placing them into a large vacuum chamber (big enough to hold 3 carboys). But what do you mean by "3 inlet nozzles." And when you say "ingress and egress of bottles," do you mean "carboys"?
So, I have not used a shopvac, but that seems woefully underpowered. Good for moving lots of air, but the ultimate vacuum on such a thing is (at best) something like 2 psi (or 4 inHg) gauge pressure. This is not nearly enough to be useful for degassing, IMHO. You could perhaps use it to suck the first little bit of air out quickly, but you will still need a pump that can suck down to a significantly lower pressure to do any reasonable degassing.

To move a decent-to-large amount of air and get to a reasonably low pressure, without risk of oil backstreaming, I think a large diaphragm pump is your best bet. These are often sold as "medical aspirators" You could also use a rotary-vane pump, but be careful of oil backdiffusion.


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## vacuumpumpman (Dec 9, 2015)

I guess you are referring to CFM rather than vacuum ?

A shop vac will not have much vacuum but it will have more CFM - 

I have tried for years to come up with an invention that can make a plastic carboy go under vacuum - no such luck as of yet. 

Still alot cheaper buying glass carboys - especially if you are only handling them when they are empty because of vacuum racking.


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## rhattin (Dec 9, 2015)

To clear up a bit of confusion, the top of the vacuum body is remove able to allow thematic carboys to be removed more easily when full. Using carboys straps to lift them out of the vacuum body : lift is about 13 inches. 
The injectors are the individual filling tubes, and they splash rack the wine into each carboy. The only restriction is that all 3 carboys have to be racked at the same time. 
The build challenge is getting good vacuum seals. Using closed cell weatherstripping so far, but it is fussy. Still a work in progress. 
Ric


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## vacuumpumpman (Dec 9, 2015)

I am a little confused ??

If you are using plastic carboys it will take less than 5 psi to collapse the plastic carboy being used.

I have tried with many sizes of ID hose diameters at 800 FT above sea level and still come up with similar results.


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## stickman (Dec 10, 2015)

If I understand correctly, the carboys will be in a vacuum chamber, so there will be no net pressure difference across the carboy wall due to the vacuum. It will be a large apparatus, but it will work once the details are ironed out. I can see this being of value for some wine-on-site shops, but it wouldn't be very practical for racking to a high shelf unless you're going to leave the whole thing up there carboys and all.


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## sour_grapes (Dec 10, 2015)

rhattin said:


> To clear up a bit of confusion, the top of the vacuum body is remove able to allow thematic carboys to be removed more easily when full.



Thanks for the additional information.

What are you making the walls of chamber out of, and what shape will you choose?

If you make the chamber in a cylindrical shape, you could probably get away with walls that are 0.065" steel. (You would want to use a dished endcap, like a hemisphere. I have even seen giant salad bowls used for this purpose.) 

If you make the chamber like a box, you will need to use very thick walls (like 3/8"?), or else use thinner walls and stiffening ribs and/or internal supports between the opposite walls. Otherwise, any decent vacuum will collapse your box, I fear.

Edit: I just calculated the diameter pipe you would need to fit three better bottles. It looks like you could get three 6 gallon Better Bottles (~10" diameter) into a 22" pipe.


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## GreginND (Dec 10, 2015)

I have seen it done but never tried it myself.

When a plastic carboy implodes from vacuum it requires part of the carboy wall to bend outward distorting it's circular shape. Think about taking the carboy and flattening it - it would need to become wider than it currently is. I saw a post once of someone simply placing a metal sleeve around the carboy. This kept the carboy from collapsing because it could not bend outward and was forced to maintain it's shape. I think some wooden hoops may also work.

I think this would work if the vacuum is not to great.


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## stickman (Dec 10, 2015)

A bit overkill, but something like this.


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## ibglowin (Dec 10, 2015)

Looks really cool but......... seems like glass carboys could be bought for a lot cheaper and solve the problem.

Here is to those who love to tinker though!


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## vacuumpumpman (Dec 10, 2015)

I tried tightly wrapping a plastic bucket with a 3'' strap all the way around the bucket - and it still collapsed at approx 4 inches of vacuum.

I am going to keep trying other ideas - I would really like to pull a vacuum on a plastic carboy without it imploding inwards.


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## stickman (Dec 11, 2015)

Glowin I agree, I don't think it is going to become a popular home winemaking tool.


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## rhattin (Dec 11, 2015)

Progress report: got the system pretty well sealed, but only at low pressure. Interesting effect is that the ambient vacuum stays at about 5.2 in regardless f the number of filling inlets in use. This is the max pressure drop that my shop vac will produce. The ambient vacuum should drop!! The fill rate is about 1.5 l per minute. 
So the real performance question is "what should the desired ambient vacuum be for effective splash degassing? Steve should be able answer this one!
Have pictures and will attach


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## sour_grapes (Dec 11, 2015)

I am having a little bit of a hard time understanding the vacuum envelope of your device. In the plywood top of the vessel, there is a large hole, sealed with a plexiglass plate, which in turn has a large hole, that is sealed with a bung (which in turn has two holes). Does this bung go into the neck of the bottle, or does it just seal the plexiglass plate, and the two tubes go down into the carboy?
Also, the plywood top has a large hole in the center. Is that sealed during operation?

Where does your vacuum cleaner hose attach?

To directly answer your question, I believe that you will need quite a bit more vacuum to degas the wine. I use a vacuum pump that can pull about 28 inHg. I think I start getting serious degassing somewhere like 15 inHg (although I admit this is a bit of a guess -- I have not actually measured it).

Finally, let's consider your conundrum regarding the vacuum level not decreasing (i.e., vessel moving towards atmospheric pressure) when you open three filler valves. I agree that this is the way the trend must go. However, you have a "pump" with a large CFM value but a poor ultimate pressure (i.e., what you called "max pressure drop"). With those conditions, you may not notice a substantial degrading of the pressure with increased flow, up until the point where the flow is more than your large-CFM pump can handle.


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## vacuumpumpman (Dec 11, 2015)

rhattin said:


> Progress report: got the system pretty well sealed, but only at low pressure. Interesting effect is that the ambient vacuum stays at about 5.2 in regardless f the number of filling inlets in use. This is the max pressure drop that my shop vac will produce. The ambient vacuum should drop!! The fill rate is about 1.5 l per minute.
> So the real performance question is "what should the desired ambient vacuum be for effective splash degassing? Steve should be able answer this one!
> 
> Well to technically degas as transferring is approx. around 15 in hg of vacuum
> ...


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## WVMountaineerJack (Dec 12, 2015)

I had proposed a vacuum chamber a long time ago but getting to build one big enough is the issue. If you put a plastic carboy in a vacuum chamber the pressure is equal everywhere so there wont be any collapse. You simple need to be able to apply a vacuum to the chamber. A shopvac would only be good for vacuuming out any wine spilled in the chamber. You are going to need a good quality vacuum pump that is not going to overheat while you are pumping. Holes would be sealed with silicone caulk with shutoff valves. You are probably going to have to go with a silicone gasket to get a good consistent and reusable seal. And a pair of safety googles for the inevitable implosion during the design phase. You might really be better off starting out with a single carboy chamber, long lengths of walls would like to buckle in, the shorter walls of a single chamber would more likely survive repeated uses. Good luck and be safe. WVMJ


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## WVMountaineerJack (Dec 12, 2015)

The cells in your seal are being stretched by the vacuum, even your current weak vacum may be destorting them, they are not really designed for that, a solid silicone or rubber seal is what you need, think like in a pressure cooker. WVMJ



rhattin said:


> To clear up a bit of confusion, the top of the vacuum body is remove able to allow thematic carboys to be removed more easily when full. Using carboys straps to lift them out of the vacuum body : lift is about 13 inches.
> The injectors are the individual filling tubes, and they splash rack the wine into each carboy. The only restriction is that all 3 carboys have to be racked at the same time.
> The build challenge is getting good vacuum seals. Using closed cell weatherstripping so far, but it is fussy. Still a work in progress.
> Ric


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## WVMountaineerJack (Dec 12, 2015)

That is exactly what is needed, plus a good pump, is it on ebay? WVMJ



stickman said:


> A bit overkill, but something like this.


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## WVMountaineerJack (Dec 12, 2015)

What is the wall of this thing made of, a big piece of pipe? WVMJ


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## stickman (Dec 12, 2015)

There are a number of units available on ebay, they look like a restaurant grade stock pot with an acrylic top modified for all of the fittings. These type of units have been traditionally used for casting resin degassing. Do a search for that and you'll find everything you need and more.


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## vacuumpumpman (Dec 12, 2015)

stickman said:


> There are a number of units available on ebay, they look like a restaurant grade stock pot with an acrylic top modified for all of the fittings. These type of units have been traditionally used for casting resin degassing. Do a search for that and you'll find everything you need and more.



I did do that - very interesting and all - 
thats alot of work just to keep plastic carboys instead of glass. I appears that most units that large - you would have to lift the full carboy and placing it in the vacuum chamber. This is seems alot of backbreaking work just in order to use plastic -= IMHO

But keep us posted on your results


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## sour_grapes (Dec 12, 2015)

I think it worth pointing out (not inspired by anyone in particular) that the OP (Ric) runs a pretty sophisticated U-Vint operation:http://www.winetimefactory.com

As he stated in the first post, he has a large number of plastic bottles, so the effort to find a way to degas them may well be worth his while. Ric, you HAVE a vacuum pump capable of going to low pressures. Have you tried using it on your new project?


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## rhattin (Jan 2, 2016)

Happy new year folks, a little update on the degassing system. Got the big bugs worked out and now able to get about 10 psi pressure differential. The neat thing is that I can degas and transfer all 3 carboys at the same time in about 3 minutes. I think that is too fast to get all the dissolved CO2 out. My research indicates that the acceptable limits for co2 is between 1000 to 300 mg/l, depending on whether it is red,white or spritzer. My research also shows that there are few home winemaker test instruments, at least reasonable ones, for CO2 concentrations.
Now I am going to venture into chemistry with some intrepedation: the fermentation process generates a lot of CO2, almost a litre of gas per litre of wine, at 20 degrees C. Since it is generated internally, I assume that the wine is completely saturated with dissolved CO2 at STP, and using a solubility coefficient of .704 molar fraction at 1 atm, indicates that there is about 20 l of Gas dissolved in 23 l of wine. As we all know, the remainder blows off throu the air locks. 
If I was able to reduce the pressure to 1/2 atm, then the solubility drops to .34 molar fraction and should release about 10 l of CO2 at STP and get sucked out by the vacuum system. 
So 10 l is .446 of a mole, or 19 gms of gas in 23 l, or 826 mg/l. And that seems to be a reasonable target concentration. 
Well, what's the conclusion?
Does this concentration level make sense? Will this shorten the ageing time. Is wine in 2 weeks now possible? I hope not. 
Some neat pictures to follow
Ric


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## rhattin (Mar 14, 2016)

Well, we now have two versions of the plastic carboy degassing system: one that will do 1 carboy at a time and the other which will do three. Got almost all of the bugs worked out of the vacuum vessels and can draw the max that the pump will suck, which is about -25 in Hg, or -12.5 psi. Does that ever get rid of a lot of gas and quickly. The expensive bit is the 1/2 in plexiglas , otherwise time and making your router perform is the hard part. Have installed a similar system at a local U-Vint operation and the wine makers love it. Better than standing around for 5 minutes with a drill and fiz-ex. 

. Now to sell it to other shops!
Ric


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