A modular, low profile PAPR system includes a blower, a filter rail chassis removably attachable to an inlet of the blower, a hose system removably attachable to the outlet of the blower, and a removable battery pack. The hose system comprises an ovular outer tube that maintains a generally flat profile for the hose as it extends across or along the operator's body. Two circular air carrying conduits are sealed within such ovular outer tube against outside contamination and provide a flat, small profile tube system that resists hoop stress applied to the outside of the hose, provides low resistance against bending, that will not inadvertently kink or seal in low radius turns, and that results in a low profile, non-collapsing hose system for delivering air from a remotely carried blower and filter assembly to the operator's protective mask.

A personal breathing system incorporating a phased-dilution demand oxygen regulator (PDDOR) includes a pressurized oxygen source and oronasal mask, a dilution valve for supplying ambient air and a demand valve for supplying pure oxygen. The PDDOR senses the mask pressure associated with the start of an inhalation cycle, maintaining pressure to the demand valve through an initial demand phase during which 100% pure oxygen is supplied through the demand valve. Control pressure within the PDDOR drops throughout the initial demand phase; when the pressure drops below a lower threshold the PDDOR main valve is closed, blocking the demand valve and cutting off the oxygen supply. Ambient air is provided to the mask via a dilution valve to preserve flow to the user.

A personal breathing system incorporating a phased-dilution demand oxygen regulator (PDDOR) includes a pressurized oxygen source and oronasal mask, a dilution valve for supplying ambient air and a demand valve for supplying pure oxygen. The PDDOR senses the mask pressure associated with the start of an inhalation cycle, maintaining pressure to the demand valve through an initial demand phase during which 100% pure oxygen is supplied through the demand valve. Control pressure within the PDDOR drops throughout the initial demand phase; when the pressure drops below a lower threshold the PDDOR main valve is closed, blocking the demand valve and cutting off the oxygen supply. Ambient air is provided to the mask via a dilution valve to preserve flow to the user.

A face mask uses a neck hanger with axillary oxygen to facilitate the flow of filtered fresh air inside the face mask for inhaling. Neck hanger filters the fresh air from the environment mixes with oxygen that is stored in the neck hanger before releasing inside the face mask for inhaling. The neck hanger is a lightweight tube that houses fans, HEPA or ULPA filters, compressed oxygen, a regulator, and a battery with a control circuit. One fan sucks the air from the environment that after being filtered and mixed with oxygen is blown into the face mask through an air pipe that is attached to both the neck hanger and face mask. The exhaled air from interior of the mask is sucked by a second fan through another air pipe, then filtered and released into the environment.

A face mask uses a neck hanger with axillary oxygen to facilitate the flow of filtered fresh air inside the face mask for inhaling. Neck hanger filters the fresh air from the environment mixes with oxygen that is stored in the neck hanger before releasing inside the face mask for inhaling. The neck hanger is a lightweight tube that houses fans, HEPA or ULPA filters, compressed oxygen, a regulator, and a battery with a control circuit. One fan sucks the air from the environment that after being filtered and mixed with oxygen is blown into the face mask through an air pipe that is attached to both the neck hanger and face mask. The exhaled air from interior of the mask is sucked by a second fan through another air pipe, then filtered and released into the environment.

The aircraft emergency oxygen supply system includes one or more sources of supplemental breathable oxygen, one or more inlet valves for one or more breathing devices, connected to the inlet valves, and one or more cabin air pressure transducers. A pressure controller controls the inlet valves in response to the one or more cabin air pressure transducers. One or more second pressure transducers may connected to conduits downstream of inlet valves to be monitored, and the pressure controller may also control operation of the inlet valves in response to the one or more second pressure transducers.

The aircraft emergency oxygen supply system includes one or more sources of supplemental breathable oxygen, one or more inlet valves for one or more breathing devices, connected to the inlet valves, and one or more cabin air pressure transducers. A pressure controller controls the inlet valves in response to the one or more cabin air pressure transducers. One or more second pressure transducers may connected to conduits downstream of inlet valves to be monitored, and the pressure controller may also control operation of the inlet valves in response to the one or more second pressure transducers.

A snow burial survival mask has an exhaust tube connected to a headgear. An intake port of the exhaust tube is positioned adjacent to a breathing portion of the headgear in order to intake exhaled carbon dioxide (CO2)-rich air. An air pump connected to the exhaust tube pump the exhaled air from the intake port to an exhaust port away from the user's face, extending survival time in a snow burial situation. At least one burial detection sensor such as a motion sensor, light sensor and/or CO2 sensor is configured to activate the air pump based on detection of a burial event.

A snow burial survival mask has an exhaust tube connected to a headgear. An intake port of the exhaust tube is positioned adjacent to a breathing portion of the headgear in order to intake exhaled carbon dioxide (CO2)-rich air. An air pump connected to the exhaust tube pump the exhaled air from the intake port to an exhaust port away from the user's face, extending survival time in a snow burial situation. At least one burial detection sensor such as a motion sensor, light sensor and/or CO2 sensor is configured to activate the air pump based on detection of a burial event.

A face mask uses a neck hanger with axillary oxygen to facilitate the flow of filtered fresh air inside the face mask for inhaling. Neck hanger filters the fresh air from the environment mixes with oxygen that is stored in the neck hanger before releasing inside the face mask for inhaling. The neck hanger is a lightweight tube that houses fans, HEPA or ULPA filters, compressed oxygen, a regulator, and a battery with a control circuit. One fan sucks the air from the environment that after being filtered and mixed with oxygen is blown into the face mask through an air pipe that is attached to both the neck hanger and face mask. The exhaled air from interior of the mask is sucked by a second fan through another air pipe, then filtered and released into the environment.