Monday, December 21, 2009

Oxygen masks in Planes.?

In many aircraft, oxygen masks are stored in compartments above the passengers. The oxygen for these masks is stored as a liquid. When it is needed, it is warmed up until it is a gas. Why is oxygen stored as a liquid rather than a gas in this situation? Any help would be appreciated- ThanksOxygen masks in Planes.?
On most commercial aircraft the passenger O2 is created by an oxygen generator chemically.





Commercial aircraft provide emergency oxygen to passengers to protect them from drops on cabin pressure. For each row of seats there are overhead masks and oxygen generators. If a decompression occurs, the panels are opened either by an automatic pressure switch or by a manual switch, and the masks are released. When the passengers pull down on the mask they remove the retaining pins and trigger the production of oxygen.





The oxidizer core is sodium chlorate (NaClO3), which is mixed with less than 5 percent barium peroxide (BaO2) and less than 1 percent potassium perchlorate (KClO4). The explosives in the percussion cap are a lead styphnate and tetracene mixture. The chemical reaction is exothermic and the exterior temperature of the canister will reach 260 掳C. It will produce oxygen for 15 to 20 minutes, about 20 liters for each passenger. The two-mask generator is approximately 63 mm in diameter and 223 mm long. The three-mask generator is approximately 70 mm in diameter and 250 mm long.Oxygen masks in Planes.?
It depends on the type of aircraft.... some aircraft will store oxygen as a gas in refillable tanks on the airplane. There will be two ';tanks'; one for the cockpit crew and one for passenger oxygen. Some newer aircraft have small oxygen generators in the overhead panels that use a chemical process that creates oxygen when the device is activated, usually by pulling down on the mask. The mask are deployed automatically when the system is first armed from the cockpit during the preflight checks and then when sensors in the cabin detect that the cabin altitude has gone above approx. 10,000ft, or by the flight crew activating a switch in the cockpit. Oxygen flow is started when the mask is pulled down. This either opens a valve that allows oxygen to flow from the tank or triggers the oxygen generator.


I have never seen on board oxygen stored as a liquid. I have seen only these two types of systems in service.





( CRJPILOT gave a very detailed explanation of the the chemical O2 generators that is accurate.)
In a gas form it would have to be stored at a high pressure.
To my knowledge passenger oxygen is stored in individual high pressure cylinders. It would be more costly to use LOX as it is continuously expanding and venting gas, which would require continous refilling. (ie.every couple of days) This would not be the most economical way to supply oxygen. It also would be very dangergous in the event of an accident, as LOX is highly combustable.
Your premise is incorrect. On most commercial airliners, passenger and crew oxygen is stored as a high-pressure gas, not as a liquid. The equipment necessary to store and transfer LOX is far more complicated and expensive than gaseous oxygen equipment.
I think that the reason it is stored as liquid is for safety purposes.
Oxygen is NOT stored as a liquid -- it is too cold. Ambient heat would vaporize it, creating high pressure. It is stored as a compressed gas, just as most industrial gases are, or generated by a chemical reaction (see previous responses).
Safety and the fact that it takes less space to store liquid than it does to store the same amount of gas.
Pardon my ignorance But I was always under the impression that oxygen in commercial aircraft was stored in the form of 2 or more chemicals that when combined release O2
To my knowledge oxygen in aircraft is in gaseous form. I fly on many so equiped aircraft from small to large and I am not familiar with a liquid system being on an airplane because of the weight of the LOX Converter. Can you explain where you got the information that LOX is used?
becuase it will take less room. liquid is the compact form.

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