Implosion Risk Assesment

[novalou]

Not sure where you are going here ???
When racking with vacuum - you will always have
Vacuum in the receiving Carboy

As long as there is wine flowing, there will be very little vacuum.

 

[vacuumpumpman]

I think for all intents and purposes, we should lump the new breed of Chinese carboys with the demijohns when it comes to vacuum durability.

No offense to any demijohn users out there.

I agree !! I think that they are so cheaply made that they should be recalled, I was referring to the Chinese carboys.

 

[winointraining]

I think that other than a lab or a high volumn industrial application ,or the occasional chinese carboy, I think were flogging an expired equine.
your going to have to have a sudden and high volumn vac to emplode .

 

[Grasshopper]

The horse might not be very active but I don't think we should pronounce it dead yet. I am sure the people that bought the defective Chinese carboys did not expect them to be defective but expected them to behave as the other carboys they have used in the past. Likewise carboys that are purchased off of Craig's List or at garage sales may look OK but have undected flaws. It is also possible that your brother-in-law dinged your carboy and "forgot" to mention it. A rare event is not necessarily less dangerous than one that is more common but likely is more dangerous because it is unexpected.

That said, it doesn't look to me that the consequences of a carboy implosion are likely to be life threatening. But you may be cut, possibly badly, plus there is a high likelihood that wine will be spilled (a tragedy in its own right). Thus some minimal precautions such as use of a secondary container and some means of catching or at least slowing down glass fragments seems prudent.

I did a web search for glass implosions and found some interesting examples for your edification. The video clips give an indication of how energetic an implosion is likely to be.

A Department of Energy report on implosions of glassware
http://www.hss.energy.gov/publications/esh_bulletins/BULL0078.html

A video of a Erlenmeyer flask implosion at Duke University
http://www.safety.duke.edu/OHS/media/Flask_implosion_Sands-shortened.mpg

An implosion of a TV CRT tube caused by heating it with a propane torch
[ame]http://www.youtube.com/watch?v=p3G8XYO1gmM[/ame]
A video on what not to do with a beer bottle
[ame]http://www.youtube.com/watch?v=Fm8OuvsSXp8[/ame]
and the following comments from someone who claims to work with high vacuum regarding the implosion of vacuum coffee makers (1 bar = 1 atmosphere of pressure = about 15 psi). Apparently implosions have been a problem with at least one type of coffee maker.

"Since I work with high-vacuum and ultra-high-vacuum equipment I would like to note that the 'highest' vacuum possible still only represents a pressure of 1 bar. A vacuum is naught but the relative absence of material (e.g. air) and on our planet that means that a container that contains 'no' air is being pressed on from the OUTSIDE by atmospheric pressure of 1 bar. This does not imply that implosions necessarily are less dangerous than explosions, but it is useful to remember just what is doing the pushing and pulling. The reason I bother writing this is that most folks have a misunderstanding about the 'power' or 'strength' of a vacuum. Sucking the air out of a plastic bottle does not in itself make the bottle collapse. It is the air pressure from the outside that forces the walls of the bottle (or vacuum coffee maker) together. If you put a closed bottle of air into a vacuum chamber and then withdrew the air from the bottle it would not collapse.

"By the way, implosions are, in fact, generally less dangerous than explosions because the inrushing air tends to keep shards from flying as far as they would if the vessel exploded. The danger is directly proportional to the volume of the vessel. With hot coffee, of course, there is still a chance of getting scalded. Implosions are often highly impressive because of the sound effects. At least theoretically, a vacuum coffee maker should withstand 1 bar without problem, however, the smallest irregularity in the glass, scratches or microcracks will result in the observed, dramatic behaviour."
Full link http://www.sweetmariascoffee.com/forum/viewtopic.php?f=7&t=809

 

[jimmyjames23]

For those that fear implosion the safety precautions are simple.
Place your clean carboy in a 25 gallon beer bucket. Rack your wine into this carboy. Perform the degassing while the container is in the bucket. Should it implode the wine will be caught in the bucket and not all over your floor.
Placing a towel around the neck of the carboy will prevent flying shards of glass should it ever implode.

 

[vacuumpumpman]

Very interesting Grasshopper

I watched the video -A video of a Erlenmeyer flask implosion at Duke University
and it appears to be an explosion, rather than an implosion - I can not make out all the details in the video. I did notice that 1 tube plugged into the wall and the other went to another container - which appeared to hear sounds of bubbling

 

[Grasshopper]

In the Duke video I think the Erlenmeyer flask is being used as a trap for anything that might come over from the vacuum experiment (distillation?) being carried out in the fume hood. IE the same way the wine bottle in the holder of the All in One is used. My guess is that this is a restaging of an accident that occurred earlier (hence the video's focus on the flask). I am pretty sure it is an implosion.

 

[vacuumpumpman]

With all the talk out there for years about the possibility of an implosion, I have yet to hear of an actual case of a carboy imploding that was of a sound state.

Dan -
I must agree - I have looked on this forum - other forums as well as google and never could find it. I have found where people have dropped them or added hot water to a cold carboy and cracked them.

 

[dangerdave]

Ok, I understand all the warnings, but with all of the people on this forum, we have yet to hear from a single person who experienced an implosion. I have racked and degassed under vacuum many hundreds of carboys with my Allinonewine pump without a single incident. I would venture to say, that if all were tallied, amongst all the wine makers we have here, many tens of thousands of carboys of wine have been racked, transfered, degassed, etc., using various and sundry home made or commericially bought vacuum pumps without a single noteable incident thus far.

So what's all the fuss about? The discussion is stimulating, and the science is fascinating, but in my book, one in a million odds are not worth the worry.

 

[jimmyjames23]

I heard one once. I was in the other room when my friend imploded a 54 L demijohn. Luckily the glass and wine was mostly contained in the Demi holder. Mind you he was using my old Gast industrial vacuum (used for carbon fiber vacuum) it pulls over a bar. I had the regulator set to -20 Hg.
My friend said he was playing with the knob and then pop!
This was a teardrop Demi. The glass was extremely thin and it was over 40 years old.

 

[dangerdave]

Great story, jimmy, but I don't think anyone has been talking about thin walled demi's. Anyone would advise against ever using a vacuum on them. The discussion has been about carboy implosion. While I appreciate your tale very much, I was wondering if anyone---anyone at all---has ever had a carboy implode under the conditions mentioned in this thread. I think the risk is highly overstated, and that using a vacuum pump drawing less than 25'' of Hg is perfectly safe on an undamaged carboy. Watching for cracks or flaws in one's carboys should be a regular practice for all who emply them whether you use a vacuum pump on them or not.

Can we agree on that?

I just want to address the real level of risk here for those who may be just starting out in wine making and are intrested in simplifying the process with something like the Allinone, but are frightened by the extent of the engineering jargon, which they may/may not fully understand.

 

[vacuumpumpman]

Thanks alot Dave
I totally understand where you are coming from !! Yes everyone should always look for any stress cracks or flaws in any glass carboy - whither you vacuum rack or not

I really like when you mentioned -
I just want to address the real level of risk here for those who may be just starting out in wine making and are interested in simplifying the process with something like the Allinone, but are frightened by the extent of the engineering jargon, which they may/may not fully understand.

Dave if you don't mind me asking - how many transfers do you think you have done with the Allinone ?

 

[jimmyjames23]

I don't think an implosion is possible with a regular carboy. Regular carboys are at least twice as thick as demijohns. Demijohns, especially really old blown ones like my friends are varying thickness. On my friends the wall thickness was less than a 16th" in some areas.
If I repair my Gast. I'll remove the regulator and make a video of an implosion attempt on my oldest carboy which has micro cracks on the base. Problem is my gauge only measures 1 bar.

 

[dangerdave]

I am currently on batch #62 using my Allinone. With 4-5 transfers per batch for rackings and degassing, that's between 240 and 300 transfers under vacuum without a failure. And that's just me!

Oh, and Steve, thanks for the very best time-saving, back-saving, and safe method for transferring and degassing my wines. I love my Allinonewinepump!

 

[sdelli]

Seriously people????? Yes I am sure we can calculate the probability of me dropping a carboy on my toe too! Anything is possible... But has anyone.... I repeat..... ANYONE have a circumstance of a carboy imploding at 22"... Tell you the truth I watch the level of vacuum more to protect the wine!!! Don't buy cheap carboys and play real procedures with them...

 

[sdelli]

I am sure a home made vacuum pump that goes to to some high settings and not regulated could become dangerous.... But I have had my bung sucked in at 22" of vacuum so I doubt it will ever have the ability to build up enough to crack the glass on a carboy.....I believe there are other things that would fail first.....