초록 ▼

A filter bypass valve is disposed in parallel with an aircraft cabin air filtration system air filter. During normal operation, air is filtered through the air filter at an air flow that meets air flow requirements of the system. The bypass valve is designed to remain closed during normal use, and t

A filter bypass valve is disposed in parallel with an aircraft cabin air filtration system air filter. During normal operation, air is filtered through the air filter at an air flow that meets air flow requirements of the system. The bypass valve is designed to remain closed during normal use, and to open if the differential pressure across the air filter reaches a predetermined opening differential pressure to allow airflow to be partially or fully diverted around the air filter.

대표청구항 ▼

We claim: 1. An aircraft cabin air filtration system comprising: an inlet configured to receive a flow of air from an airflow source; an outlet configured to exhaust the flow of air to the aircraft cabin; an air filter positioned between the inlet and the outlet, the air filter being fluidly couple

We claim: 1. An aircraft cabin air filtration system comprising: an inlet configured to receive a flow of air from an airflow source; an outlet configured to exhaust the flow of air to the aircraft cabin; an air filter positioned between the inlet and the outlet, the air filter being fluidly coupled to the inlet and the outlet and configured to filter the flow of air, whereby a differential pressure is developed between the inlet and the outlet; and a bypass valve positioned between the inlet and the outlet and in parallel with the air filter, the bypass valve being fluidly coupled to the inlet and the outlet and movable between an open position, in which the flow of air is bypassed around the filter, and the closed position, in which the flow of air is not bypassed around the filter, the bypass valve configured to move to the open position when the differential pressure magnitude reaches a predetermined opening value, the filter bypass valve including: a valve body having one or more flow channels extending therethrough, each flow channel having a cross sectional flow area, and one or more flappers rotationally mounted on the valve body and configured to substantially seal the flow channels when the bypass valve is in the closed position and unseal the flow channels when the bypass valve is in the open position, each flapper having a surface area, wherein the cross sectional flow area is less than about 50% of the surface area. 2. The system of claim 1, wherein the predetermined opening differential pressure value is the differential pressure across the filter at which the air filter is unable to meet a predetermined air flow rate. 3. The system of claim 1, wherein the bypass valve further includes: one or more torsion springs coupled to the flappers, each torsion spring having a torsional force configured to urge at least one flapper toward the closed position. 4. The system of claim 1, wherein each flapper moves rotationally between the valve open and closed positions, and wherein the bypass valve further includes: one or more flapper stops coupled to the valve body and configured to limit rotational movement of each flapper in the open position. 5. The system of claim 4, wherein the flapper stop limits rotational movement of the flappers to a rotational angle of less than about 90-degrees. 6. The system of claim 5, wherein: each flow channel has a cross sectional shape that is a substantially rectangular parallelogram; and the flapper stop limits rotational movement of the flappers to a rotational angle of about 32-degrees. 7. The system of claim 6, wherein: the valve body includes an upstream surface having a centerline; and the valve includes two flow channels symmetrically disposed on the valve body upstream surface on opposite sides of, and adjacent to, the centerline. 8. The system of claim 5, wherein: each flow channel has a cross sectional shape that is substantially crescent shaped; and the flapper stop limits rotational movement of the flappers to a rotational angle of about 16-degrees. 9. The system of claim 8, wherein: the valve body includes an upstream surface having a centerline and an outer periphery; and the valve includes two flow channels symmetrically disposed on the valve body upstream surface on opposite sides of the centerline and adjacent the valve body outer periphery. 10. The system of claim 1, further comprising: an annular shroud coupled to, and extending axially from, the valve body. 11. The system of claim 10, wherein the annular shroud is configured to surround each flapper when the valve is in the closed position. 12. The system of claim 11, wherein the annular shroud is configured to at least partially surround each flapper when the valve is in the open position. 13. A valve, comprising: a valve body having one or more flow channels extending therethrough, each flow channel having a cross sectional flow area; one or more flappers rotationally mounted on the valve body and rotationally movable between a closed position and an open position, each flapper configured to substantially seal one of the flow channels when it is in the closed position and to rotate to at least a predetermined rotational angle relative to its closed position when it is in the open position, each flapper having a surface area; an annular shroud coupled to and extending axially from the valve body, the annular shroud surrounding each flapper when the flapper is in the closed position; and one or more flapper stops coupled to the valve body and configured to limit the predetermined rotational angle of each flapper to less than 90-degrees, wherein the cross sectional flow area is less than about 50% of the surface area. 14. The valve of claim 13, further comprising: one or more torsion springs coupled to the flappers, each torsion spring having a torsional force configured to urge at least one flapper toward the closed position. 15. The valve of claim 13, further comprising: each flow channel has a cross sectional shape that is a substantially rectangular parallelogram; and each flapper stop limits rotational movement of a flapper to a rotational angle of about 32-degrees. 16. The valve of claim 13, wherein: the valve body includes an upstream surface having a centerline; and the valve includes two flow channels symmetrically disposed on the valve body upstream surface on opposite sides of, and adjacent to, the centerline. 17. The valve of claim 13, wherein: each flow channel has a cross sectional shape that is substantially crescent shaped; and the flapper stop limits rotational movement of the flappers to a rotational angle of about 16-degrees. 18. The valve of claim 17, wherein: the valve body includes an upstream surface having a centerline and an outer periphery; and the valve includes two flow channels symmetrically disposed on the valve body upstream surface on opposite sides of the centerline and adjacent the valve body outer periphery. 19. The valve of claim 13, wherein the annular shroud is configured to surround each flapper when the flapper is between the closed position and a predetermined partial-open angle, the predetermined partial-open angle having a magnitude less than the predetermined rotational angle in the open position. 20. A valve, comprising: a valve body having one or more flow channels extending therethrough, each flow channel having a cross sectional flow area; and one or more flappers rotationally mounted on the valve body and rotationally movable between a closed position and an open position, each flapper configured to substantially seal one of the flow channels when it is in the closed position and to rotate to at least a predetermined rotational angle relative to its closed position when it is in the open position, each flapper having a surface area, wherein the cross sectional flow area is less than about 50% of the surface area.