SpudFiles

my frend is throing out the air bag in his car and im wondering what type of valve it uses it is electricleay activated and wondering if it could be manipulated fo use in a pnumatic lancher.[/b]

Air bags use a chemical reaction to quickly generate large amounts of gas. There is no valve.

There is no valve to speak of

Basically there are some explosives inside the bag that explode when the controller is electically charged

One word of warning though, they are very dangerous even when taking them out, just watch out

Dave

oh thanks i thought it was just stored co2 its already been discharged

yeah anything that can do this http://www.youtube.com/watch?v=CXYbn3uQSlk is something that could be quite dangerous

Not all airbags use chemical reactions now. Some of the newer versions use an extremely high pressure gas cylinder that's discharged through some sort of relatively high flow, quick release valve. If this is one of those models, it *should* be possible to remove the valve.

If it's an older car though, chances are it uses the decomposition of sodium azide into sodium metal and nitrogen gas to inflate the bag. Sodium azide is explosive, fairly sensitive, and EXTREMELY toxic. If it's already been discharged, taking it apart shouldn't be too much of a risk either way.

Kinetic, newer ones will probably be a solenoid valve.

maggotman wrote:oh thanks i thought it was just stored co2 its already been discharged

Look into the emergency slide things for exiting a plane in case of an emergency... They use stored CO2.

Airbags of like 10 years ago used a primary explosive called Sodium Azide. they used very little of it however. Newer air bags used compressed nitrogen I believe - not sure of the valves tho, they would be interested, perhaps it's an electronically triggered bust disc.

edit - kinetic already mentioned the sodium azide

spudtyrrant wrote:yeah anything that can do this http://www.youtube.com/watch?v=CXYbn3uQSlk is something that could be quite dangerous

I wouldn't call this a terribly dangerous demonstration of airbag power. A pumpkin is a relatively weak structure from the inside out, especially one that has had much of its walls already carved out....and in this case the airbag's final diameter is greater than that of the pumpkin's. Did you really expect the pumpkin to survive this?..

A further word of caution, many air bags have two charges. One for mild fender benders and a double charge for a major impact. Don't assume a used airbag is safe.

As usual, a link to validate my claim.
http://cms.firehouse.com/web/online/Uni ... -/19$32424

A deployed air bag can't be assumed safe.

that would make sence there is 2 conectors both with 2 contacts

the bag is cut off

maggotman wrote:that would make sence there is 2 conectors both with 2 contacts

the bag is cut off

If the bags were to use the common ground (ie, vehicle frame) as ground, then there would not be a need for 2 contacts per charge. One contact per charge is all that would be required.

Alas, I've no knowledge/experience with airbags so I don't know what they look like.

D_Hall wrote:If the bags were to use the common ground (ie, vehicle frame) as ground, then there would not be a need for 2 contacts per charge. One contact per charge is all that would be required.

I would think the wiring would still use two wires per charge. Vehicle ground wouldn't be reliable in a crash and some of the air bags, the steering wheel one in particular, may not have a reliable vehicle ground.

In any case ... be very careful when fiddling with these systems. Regardless of how they work (exposive or compressed gas) they contain potentially lethal energies. People have been killed by air bags. Even when they function as designed they often break bones and rip off skin.

no valve it picks up on fast stops or impact and makes a small spark in a small chamber like thing that filled with special pills that react to the heat and expand into gas very fast