Personal disposable emergency breathing system with dual air supply

A personal emergency breathing system comprising:

• a compartment;
• a canister disposed in said compartment and deployable therefrom, a flexible external air supply conduit disposed in said compartment with said canister for connection to a source of breathable air other than ambient air, said flexible conduit being connected to said canister, and at least in part, being deployable from said compartment with said canister, and a normally closed valve for precluding air flow from the external source to said canister;
• said canister having a body with an opening and a cover normally closing said opening;
• an air filtration unit disposed within the body of said canister for filtering ambient air and having an air inlet for receiving ambient air and an air outlet, the ambient air being receivable through said air inlet into said filtration unit for filtering and passage through said air outlet;
• a mouthpiece carried by said canister for receiving filtered air from the outlet of said filtration unit;
• a hood carried by said canister and enveloping said mouthpiece, said mouthpiece and said hood being disposed in a collapsed condition in said canister adjacent said opening and between said cover and said filtration unit whereby, upon deployment of said canister from said compartment and opening said cover, said hood and mouthpiece are deployable from said canister to a location external to said canister, said hood having an opening for receiving a individual's head and neck whereby the hood, when deployed, may envelop an individual's head;
• means for connecting said hood and said mouthpiece to said canister in said collapsed condition and when deployed therefrom;
• an air flow conduit carried by said canister body bypassing said filtration unit and having an air flow inlet and an air flow outlet, a releasable coupling connecting said air flow inlet and said flexible external air supply conduit, said air flow outlet lying in communication with said mouthpiece whereby said flexible external air supply conduit and said air flow conduit enable flow of air from said external source of air into said mouthpiece when said canister is deployed from said compartment and said hood and said mouthpiece are deployed from said canister and without the air from the external source passing through said filtration unit;
• and
• means for opening said normally closed valve when said canister is deployed from said compartment to flow air from said external source into said mouthpiece.