Patent ID: 6371116
Filing Date: 2002-04-16
Classification: A62B,Y10S

Abstract:
A multiple zone protective enclosure comprising:an air-impermeable hood; said air-impermeable hood adapted to receive a wearer's head; said air-impermeable hood having a closed first end and an open second end; an air-impermeable transparent viewing area integrated into said air-impermeable hood, said air-impermeable transparent viewing area adapted to permit outward vision by said wearer; a first substantially airtight seal having a predetermined resistance to airflow, having an outer peripheral edge secured to said second end of said air-impermeable hood, and having an inner peripheral edge adapted to sealingly engage a wearer's neck; a second substantially airtight seal having a predetermined resistance to airflow, having an outer peripheral edge secured to said second end of said air-impermeable hood and having an inner peripheral edge adapted to sealingly engage a wearer's neck; said inner peripheral edge of said first substantially airtight seal adapted to sealingly engage said wearer's neck along a first annular line of contact and said inner peripheral edge of said second substantially airtight seal adapted to sealingly engage said wearer's neck along a second annular line of contact, said first and second annular lines of contact being disposed in vertically spaced apart relation to one another when said hood encloses the head of said wearer; a protection zone adapted to enclose the head of said wearer, said protection zone being defined by said air-impermeable hood and said first substantially airtight seal, said protection zone adapted to surround said head of said wearer; a purge zone defined between said first and second substantially airtight seals, said purge zone adapted to encircle said neck of said wearer; a respiration interface having an inhalation pathway and an exhalation pathway, said inhalation pathway adapted to receive purified air and said exhalation pathway adapted to dispatch exhaled air; an exhalation conduit disposed in fluid communicating relation between said exhalation pathway and said purge zone; said first and second substantially airtight seals providing a substantially universal fit; whereby when said first predetermined resistance to airflow of said first substantially airtight seal is greater than said second predetermined resistance to airflow of said second substantially airtight seal, exhaled air intermittently flows into said purge zone until a predetermined threshold pressure is reached, whereupon said exhaled air flows into ambient by overcoming the sealing power of said second substantially air tight seal; whereby when said first predetermined resistance to airflow of said first substantially airtight seal is substantially equal to said second predetermined resistance to airflow of said second substantially airtight seal, exhaled air intermittently flows into said purge zone until a predetermined threshold pressure is reached, whereupon said exhaled air flows in substantially equal amounts into said protective zone and to ambient by substantially simultaneously overcoming said first and second predetermined resistances to airflow of said first and second substantially air tight seals; and whereby when said first predetermined resistance to airflow of said first substantially airtight seal is less than said second predetermined resistance to airflow of said second substantially airtight seal, exhaled air intermittently flows into said purge zone until a predetermined threshold pressure is reached, whereupon said exhaled air flows into said protection zone, thereby pressurizing said protection zone, until pressure is equalized on opposite sides of said first substantially airtight seal so that subsequent exhalations cause exhaled air to flow out of the purge zone into ambient.