초록 ▼

Open circuit emergency breathing apparatus is disclosed which includes a pressure demand valve selectively connectable to primary and secondary sources of breathing gas under pressure to direct breathing gas to a breathing hose attached to the valve and then to a face mask worn by a user of the appa

Open circuit emergency breathing apparatus is disclosed which includes a pressure demand valve selectively connectable to primary and secondary sources of breathing gas under pressure to direct breathing gas to a breathing hose attached to the valve and then to a face mask worn by a user of the apparatus. The pressure demand valve includes a diaphragm actuated flow control member and a tubular breathing gas sensor operable in response to inhaling and exhaling by the user to control displacements of the diaphragm and corresponding displacements of the flow control member in a manner which enables obtaining and maintaining the flow of appropriate volumes of breathing gas to the user of a wide range of low to high breathing rates and a wide range of breathing gas supply pressures.

대표청구항 ▼

Open circuit emergency breathing apparatus adapted to be connected to a source of breathing gas under pressure and comprising, a pressure demand valve, and user utilization means including breathing hose means for directing breathing gas from said pressure demand valve to a user of the apparatus, sa

Open circuit emergency breathing apparatus adapted to be connected to a source of breathing gas under pressure and comprising, a pressure demand valve, and user utilization means including breathing hose means for directing breathing gas from said pressure demand valve to a user of the apparatus, said pressure demand valve including housing means, said housing means including flow passageway means therethrough having an inlet end and an outlet end, means on said housing means for connecting said inlet end of said passageway means to said source of breathing gas under pressure, means on said housing means for connecting said breathing hose means to said outlet end of said passageway means between said inlet and outlet ends thereof and including valve member means supported in said housing means for displacement between open and closed positions, said valve member means in said open position thereof opening said passageway means such that breathing gas can flow through said passageway means from said source through said outlet end to said user utilization means, said valve member means in said closed position thereof closing said passageway means to the flow of breathing gas therethrough from said source, said housing means including means providing a diaphragm chamber, diaphragm means mounted in said housing means and dividing said diaphragm chamber into first and second chamber portions, said second chamber portion being vented to atmosphere, said diaphragm means being displaceable between first and second positions respectively in response to decreases and increases in the pressure in said first chamber portion relative to atmospheric pressure, valve member actuator means displaced in response to displacement of said diaphragm means such that said valve member means is respectively in said open and closed positions thereof when said diaphragm means is in said first and second positions thereof, said diaphragm means having a third position between said first and second positions thereof and said valve member means having a partially open position between said open and closed positions thereof, said diaphragm means being in said third position when the pressure in said first and second chamber portions is equal and said valve member actuator means positioning said valve member means in said partially open position when said diaphragm means is in said third positions, and tubular breathing sensor means connecting said first chamber portion in flow communication with said user utilization means such that the flow of breathing gas from said source to said outlet end of said passageway means is precluded from entering said first chamber portion and the inhaling and exhaling of a user respectively decreases and increases the gas pressure in said first chamber portion through said tubular breathing sensor means.