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Author Topic: How can I make a self-inflating balloon for emergencies?  (Read 14208 times)

Offline MrSirismoon

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I am trying to work out a way to make a self inflating balloon that will pack down into a small size, but when activated inflate and float in the air for a few hours.
Any device would need to be waterproof and safe enough to travel on planes with etc.

Maybe two chemical that are mixded on activation and make a gas, or some way to heat the air in the balloon to make it float?

Any ideas appreciated.
Thanks
« Last Edit: 05/02/2012 09:47:56 by chris »


 

Offline CliffordK

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Re: Self inflating balloon for emergency use
« Reply #1 on: 05/02/2012 01:16:23 »
For a balloon that "floats", you need one of two things.

1: Lighter than air gas (Hydrogen, Helium, Methane)
2: Hot Gas

How much automation do you need?  A lot of what you come up with may be hard to carry on a plane. 

I'm imagining a small butane lighter for a hot air balloon, but it seems a bit cumbersome as many balloon materials are flammable, and if you didn't continuously add heat, the balloon wouldn't stay up.

What I'd probably do is to make an electrolysis device that you could use to inflate ordinary rubber or Mylar balloons with Hydrogen.  You could make it fairly small, and it wouldn't be a problem for planes, although people often use a caustic chemical in them (NaOH or KOH).  After blowing up the balloon, you would likely just separate the balloon from the inflater.
 

Offline CliffordK

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Re: Self inflating balloon for emergency use
« Reply #2 on: 05/02/2012 09:41:37 »
Ideally you could find small Helium tanks the size of the disposable CO2 cannisters for air guns (also used for self filling life jackets).

You might have troubles with Helium cartridges on an airplane though.

I'm seeing larger party style canisters, but very few mini-canisters for Helium.

There is a description of a person that has added a tire valve to a CO2 cartridge.  However, without a good engineered design, I would consider it somewhat questionable for use.
 

Offline MrSirismoon

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Re: How can I make a self-inflating balloon for emergencies?
« Reply #3 on: 05/02/2012 17:30:53 »
Hello,
Yes the butane option I had thought of but in emergency situation especially on the ocean I would be worried it would not ignite due to being wet (Though I guess it could be sealed until use), or would be too cumbersome to stay attached to the balloon, or not be easy to take underwater (if diving etc).
Perhaps another slow heating substance that would generate heat by means of mixing with another substance may work.?
The electrolysis idea is interesting, but the caustic chemicals may be a worry unless they could be contained within a light weight and sealed unit that just inflates the balloon and stays attached or is easily removed.
The small helium canisters would be an easy option but I dont think is very practical to get something small enough to carry around though especially on airplanes etc.

Keep the ideas coming.
Thanks
 

Offline syhprum

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Re: How can I make a self-inflating balloon for emergencies?
« Reply #4 on: 05/02/2012 21:18:52 »
The air bags fitted to cars are just such devices and are readily available thru car spares suppliers but I think security would take a dim view of you taking them on an airline
 

Offline CliffordK

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Re: How can I make a self-inflating balloon for emergencies?
« Reply #5 on: 05/02/2012 22:36:59 »
Airbags in cars use CO2, I think, which is heavier than air.  Although the deployment mechanism could be used to deploy Helium.

I think you can use other salts with the electrolysis, for example NaCl which would be ok for transport.

I think the problem with using NaCl is that one gets pure Hydrogen Gas + a mix of Oxygen and Chlorine Gas.

You want the H2 gas, so the chlorine shouldn't be a problem in small quantities.
 

Offline CliffordK

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Re: How can I make a self-inflating balloon for emergencies?
« Reply #6 on: 08/02/2012 19:57:52 »
There are very few "Lighter than Air" gases.  Methane is lighter than air, but you may not get adequate lift.  You can produce methane with methanogen bacteria, and the appropriate food for them.  However, I'm doubtful that you will get adequate lift.

Helium is best stored in bottles. 

You can generate hydrogen with some of the lighter metals (Lithium & Sodium) + Water.  It is a very exothermic reaction, and thus somewhat dangerous.  However, in theory it could be run in an anoxic environment with deoxygenated water. to produce Hydrogen Gas.  With the exothermic reaction, you would probably not want your piece of sodium or lithium metal in contact with the inside of your balloon which means some kind of inflation and release mechanism.

I don't know the travel restrictions.  Sodium and Lithium probably should be restricted, if they aren't.  You certainly would not want to carry them in any system with the possibility of them accidentally getting wet.

Similar to sodium metal, metal hydrides have also been proposed for hydrogen generation.
http://en.wikipedia.org/wiki/Sodium_hydride#Hydrogen_storage


Keep in mind that hydrogen gas has some risk of explosion, and I would probably limit the capacity to a couple of cubic feet.
« Last Edit: 08/02/2012 20:06:53 by CliffordK »
 

Offline syhprum

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Re: How can I make a self-inflating balloon for emergencies?
« Reply #7 on: 09/02/2012 08:58:19 »
I checked out Acetalyne as its easy to store and generate but the density is very little diferent to air.
 

Offline CliffordK

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Re: How can I make a self-inflating balloon for emergencies?
« Reply #8 on: 09/02/2012 19:15:37 »
Yes, calcium carbide generates Acetylene.

You can get a good estimate of the comparative density of the gas by looking at the molecular weight.
N2: 14+14 = 28
O2: 16+16 = 32
C2H2: 24+2 = 26

CH4: 12+4=16 (just over half the density of air)
NH3: 14+3=17
H20: 16+2=18 (obviously a liquid at low temps, but this is one reason water vapor tends to rise, and form clouds above us).
Ne: 20

H2: 2
He: 4

I believe that Lithium and Beryllium tend to form salts and high melting point solids.

Anyway, this is the reason that the list of lighter than air gases is very short, and to get any effective lifting capabilities, one may be limited to 2 gases, Hydrogen and Helium, and their isotopes, although one could use Methane and Ammonia.

Hot air, of course, also uses temperature differences to create the gradient.

If one could make a lightweight, strong, rigid structure, one could also conceivably create a container that would contain a vacuum, and thus would be lighter than air.
For example, create a hollow sphere of Silica Aerogel, or Metallic Microlattice, cover it with a thin airtight film, and evacuate.
 

Offline damocles

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Re: How can I make a self-inflating balloon for emergencies?
« Reply #9 on: 12/02/2012 22:50:32 »
Electrolysis is not, unfortunately, a practical idea.

(1) It is much too slow for an "emergency"
(2) large capacity batteries or other generating devices are much too heavy, though I guess they could be detached when the balloon is filled.

For the record: to generate 10 litre of hydrogen by electrolysis in 1 minute would require a current of about 800 amp minimum (and, obviously, a battery/generator capacity of at least 13 amp hours).

---

On a different aspect, I think that the gas in car airbags is nitrogen, and I think it is generated by explosive decomposition of sodium azide:
http://en.wikipedia.org/wiki/Airbag
 

Offline CliffordK

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Re: How can I make a self-inflating balloon for emergencies?
« Reply #10 on: 13/02/2012 00:12:07 »
Thanks for pointing out the chemical nature of the airbags.

I do think the best method for the balloons would be designing them to detach from the generator.  Inflating them with either a Helium Cannister, or use reactions of either alkali metals, or alkali hydrides (or something similar).

Liquid water is probably just as good as anything to react with the alkali metals or alkali hydrides.  Perhaps in a crushable plastic or glass vial.  One could also react with acids such as acetic acid that is a solid at moderate temperatures.  Or, perhaps various sugars and starches with higher melting points.

Would it be possible to find a mixture that would require activation energy like the sodium azide used in airbags?  Keeping in mind, of course, that one would not want to initiate oxidization of the hydrogen that is produced, so it should be packed under Hydrogen or Helium, or other generally non reactive environment.
 

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Re: How can I make a self-inflating balloon for emergencies?
« Reply #10 on: 13/02/2012 00:12:07 »

 

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