[RogueTechDesigns]

Hello, we are 3 seniors, Josh, Jeremy and Heath, from Niskayuna High School and were looking for help. We are all enrolled in a technology course called Engineering Design and Development (EDD) and in this course we must brainstorm problems, confirm they actually are problems, come up with some solutions, contact professionals in the field, and design and prototype our final solution. We currently have a problem and are working on our solutions, our problem is carbonated beverages overflowing when you open them shorty after they are dropped. We have begun research on the issue of carbonation and were hoping you could help us on how to control carbonation. One of our ideas was to add a screen that would only let the extra CO2 out but would not let out the beverage. What we are currently struggling with is finding a type of screen that IS FOOD SAFE but won't lets drinks through. Any ideas?

This post has been edited by Phi for All: 10 February 2012 - 07:22 PM
Reason for edit: email tags removed

[Phi for All]

!

Moderator Note

I removed your email tags since we want all discussion on our topics to occur here at the site. More knowledge for everyone that way.

[Xittenn]

CO2 is bigger than H20 and so fine filtration is not really an option unless there is an ionic choke that selectively plays on the ionic properties of water. So the filtration device would allow anything as large as CO2 through but no larger. I believe you could accomplish this using carbon fiber nano tubules. Sugars and everything else couldn't pass through the filter because they would just be too big. Carbon nano tubules are not a fabric and so would not trap these larger molecules. Trapping larger molecules that can then be exposed to environmental air is how food born pathogens are allowed to grow. This sort of filtration device would be awfully expensive for a pop can to simply prevent overflow, but it would make for an excellent research project. You would gain a lot of knowledge in doing so.

[swansont]

The problem with a membrane approach is that for liquids and gases you are still dealing with individual molecules and as Xitten notes, CO2 is bigger than H20.

Also, where would the vent be for this? It can't block the path for pouring, so you'd need to add a second pathway, which I would expect to drive up can/bottle production costs.

BTW, I'm a Nisky alum. Small world.

[John Cuthber]

With a fobbing drink you are trying to let gas through, but not liquid.
That's a solved problem.
http://en.wikipedia.org/wiki/Gore-Tex

But that still leaves the problem of how to drink the product. You would need a second path as Swansont says.
And that leaves the question of stopping that opening from fobbing.

BTW, is a Nisky alum like chrome alum?

[Phi for All]

John Cuthber, on 12 February 2012 - 02:46 PM, said:

BTW, is a Nisky alum like chrome alum?

Yes, but less shiny.

[swansont]

Phi for All, on 12 February 2012 - 05:06 PM, said:

Yes, but less shiny.

You callin' me dull?

[Carvone]

Carbon dioxide is added to soft drinks because it has been shown to give a preferred sensory mouthfeel when consuming due to the tiny bubbles in the mouth creating the effervescence. If you create a membrane that allowed out the excess CO2 only, it would have to be at the nozzle of the bottle where once it was opened it purged out the CO2 and no liquid, and then a further step of removing the mesh would be required to allow pouring of the drink out of the bottle. I am not sure what membrane materials might allow this, but I know if there is a slow purge due to only opening a small orifice the CO2 gas will be preferentially purged out, such as what I will do when a bottle falls and only partially twist open the cap only slightly such that no liquid exits while the gas pressure does exit over a prolonged period of time. Perhaps instead of a membrane, think of a small orifice purge valve at the cap.

Also, another solution is dramatically lowering the temperature of the soft drink although this is not an option if it is desired to consume the drink immediately. In solution, dissolved carbon dioxide turns to carbonic acid, and the dropping of the pop bottle causes nucleation of CO2 bubbles which decreases the solubility of the carbonic acid. By putting the bottle in the freezer for a few hours should alleviate the problem of the fizzing pop since at lower temperatures CO2 is more soluble in water as carbonic acid.