Aircraft crew member protective breathing apparatus
A self-contained breathing device for use in fighting fires comprising a hood for covering a wearer's head, a membrane for sealing the hood to create a breathing chamber inside the hood, and a source of oxygen disposed inside the hood. The source of oxygen is connected to the user by a conduit inside of the hood, and another conduit directs user-exhaled carbon dioxide to the source of oxygen. The breathing device includes a visual indicator inside of the hood that reacts to the presence of a gas within the hood and provides visual feedback to the user based on a quantity of the gas present in the hood.
1. A breathing apparatus comprising:
a hood and a self-contained oxygen source inside the hood, the self-contained oxygen source located behind a user's head;
a first tube connecting the self-contained oxygen source and terminating at a position above the user's head for delivering oxygen to a breathing area;
a second tube connecting a user's mouth piece to the self-contained oxygen source;
a transparent viewing window on the hood; and
a first internal indicator on the transparent viewing window and facing the user inside the hood that indicates to the user that the self-contained oxygen source behind the user's head is providing a threshold oxygen level inside a breathing chamber at the breathing area.
2. The breathing apparatus of claim 1 wherein the self-contained oxygen source comprises a canister containing KO 2 (potassium superoxide) and a starter candle that activates a production of oxygen using NaCIO 3 .
3. The breathing apparatus of claim 1 wherein the first internal indicator automatically responds to a change in a level of oxygen via a chemical reaction that occurs on the first internal indicator.
4. The breathing apparatus of claim 1 wherein the self-contained oxygen source is initiated by a chlorate candle.
5. The breathing apparatus of claim 4 wherein the chlorate candle is actuated by pulling a pin.
6. The breathing apparatus of claim 5 wherein the pin is pulled automatically by adjusting the breathing device to the user.
7. The breathing apparatus of claim 1 wherein the first internal indicator is a thin film applied to an interior surface of the hood within view of the user.
8. The breathing apparatus of claim 7 , wherein the thin film comprises a catalyzed thin film of metal oxide.
9. The breathing apparatus of claim 7 , wherein the thin film comprises an aqueous dispersion of a semiconductor, a sacrificial electron donor, an aqueous solution of a redox-indicator dye, and an encapsulating polymer.
10. The breathing apparatus of claim 1 , wherein the first internal indicator reacts to an oxygen level present in the hood to spell a word.
11. The breathing apparatus of claim 1 , wherein the first internal indicator indicates a value on a scale corresponding to a concentration of gas inside the hood.
12. The breathing apparatus of claim 11 , wherein said gas is oxygen.
13. The breathing apparatus of claim 11 , wherein said gas is carbon dioxide.
14. The breathing apparatus of claim 1 , wherein the first internal indicator is sensitive to ultraviolet light.
15. The breathing apparatus of claim 1 , wherein the first internal indicator changes color as a result of a change in a concentration of a gas within the hood.
16. The breathing apparatus of claim 1 , wherein the first internal indicator detects and visually displays a percentage of carbon dioxide in the hood.
17. The breathing apparatus of claim 1 , wherein the first internal indicator detects and visually displays a percentage of oxygen in the hood.