Claims
- 1. A gas mask assembly comprising a facepiece defining an interior chamber for filtered air and including at least one inhalation opening for passage of filtered air from the atmosphere to the interior chamber; and a filtration canister removably mounted to the facepiece and in fluid communication with the at least one inhalation opening for passage of purified atmospheric air to the facepiece interior chamber;
a self-sealing valve mounted in the at least one inhalation opening and adapted to seal the at least one inhalation opening to prevent inhalation of air therethrough when the filtration canister is removed from the facepiece and to open the at least one inhalation opening to permit inhalation of air therethrough when the gas filter canister is mounted to the facepiece.
- 2. The gas mask assembly according to claim 1 wherein the filtration canister includes a projection for opening the self-sealing valve when the filtration canister is mounted to the facepiece.
- 3. The gas mask assembly according to claims 1 or 2 wherein the self-sealing valve includes an elastomeric diaphragm mounted in the at least one inhalation opening.
- 4. The gas mask assembly according to claim 3 wherein the facepiece includes an exterior valve seat associated with the at least one inhalation opening; and
the elastomeric diaphragm includes a hinge and a skirt, the skirt having a sealing surface that is biased into contact with the exterior valve seat.
- 5. The gas mask assembly according to claim 4 wherein the exterior valve seat is formed on a surface external to the interior chamber of the facepiece.
- 6. The gas mask assembly according to claim 5 wherein the facepiece further includes a filtration canister mount and the filtration canister is releasably mounted to the facepiece through the filtration canister mount and the exterior valve seat is formed on the filtration canister mount.
- 7. The gas mask assembly according to any of claims 4-6 wherein the filtration canister projection is adapted to act on the hinge to pivot the skirt away from the sealing surface as the canister is mounted to the canister mount.
- 8. The gas mask assembly according to claim 6 or 7 wherein the filtration canister mount has an opening in communication with the at least one inhalation opening.
- 9. The gas mask assembly according to any of claims 6-8 wherein the filtration canister mount includes connecting elements for releasably mounting the filtration canister through a twist and lock connection.
- 10. The gas mask assembly according to any of claims 6-9 wherein the self-sealing valve has a central portion through which the valve is attached to the filtration canister mount and the filtration canister mount has an upstanding flange between the exterior valve seat and the central portion of the self-sealing valve, the upstanding flange is shaped to serve as a fulcrum for unseating the sealing portions of the self-sealing valve from the exterior valve seat when a filtration canister is mounted to the filter mount.
- 11. The gas mask assembly of claim 10 wherein the upstanding flange is annular in shape.
- 12. The gas mask assembly according to any of claims 4-11 wherein the exterior valve seat is annular in configuration and the valve skirt sealing surface is annular in configuration.
- 13. The gas mask assembly of claim 1 and further comprising an inner valve seat on an inner side of the facepiece and surrounding the at least one inhalation opening, and an inhalation valve mounted in the at least one inhalation opening and having sealing portions adapted to seal against the inner valve seat in the absence of a negative pressure differential between the interior chamber and the atmosphere, and the inhalation valve is further adapted to unseat from the inner valve seat in the presence of a negative pressure differential between the interior chamber and the atmosphere.
- 14. A filter canister for a gas mask comprising:
a housing with an inlet opening at a first end and an outlet at a second end; a first filter medium mounted at the first end of the housing and in communication with the housing inlet opening; a second, different filter medium arranged is axial stacked relationship to the first filter medium in the housing and at the second end of the housing in communication with the outlet opening; a barrier between the first and second filter medium to force air entering the housing through the inlet opening from a central portion of the first filter medium in a radial direction through the first filter medium to an outer portion thereof, then axially to an outer portion of the second filter medium, then radially through the second filter medium to a central portion of the second filter medium to the outlet opening of the housing.
- 15. A filter canister for a gas mask according to claim 14 wherein the first filter medium is a particulate filter adapted to remove aerosols, particulate materials and droplets.
- 16. A filter canister for a gas mask according to claim 14 or 15 wherein the second filter medium is a adsorbent carbon filter medium adapted to remove toxic gases.
- 17. A filter canister for a gas mask according to any of claims 14-16 wherein the housing is adapted to removably mount a supplemental filter at the first end thereof.
- 18. A filter canister for a gas mask according to claim 17 and further comprising a supplemental filter mounted to the first end of the filter canister housing, and wherein the supplemental filter is adapted to intercept toxic industrial materials.
- 19. A filter canister for a gas mask according to claim 18 wherein the supplemental filter is a radial-flow filter.
- 20. A filter canister for a gas mask according to claim 18 wherein the supplemental filter is an axial-flow filter.
- 21. A gas mask assembly comprising a facepiece defining an interior chamber for filtered air and including at-least one inhalation opening for passage of filtered air from the atmosphere to the interior chamber; and a filtration canister removably mounted to the facepiece and in fluid communication with the at least one inhalation opening for passage of purified atmospheric air to the facepiece interior chamber;
the facepiece including a visor comprising a pair of spaced optical panels for user visibility through the facepiece; and a hinge mounted to and between the spaced optical panels for relative rotational movement of the two optical panels with respect to each other.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application S.No. 60/198,012, filed Apr. 18, 2000.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/US01/12545 |
4/17/2001 |
WO |
|