Method and apparatus for controlling the concentration of carbon dioxide in an aircraft cabin
First Claim
1. Apparatus for controlling the ventilation of a pressurized enclosed space, comprising:
- (a) a carbon dioxide sensor disposed so as to monitor carbon dioxide concentration in the enclosed space;
(b) a valve disposed in a fluid path through which air drawn from the space is selectively vented from the space or recirculated back into it;
(c) air pack means for supplying fresh pressurized air to the space; and
(d) control means, connected to the carbon dioxide sensor, the pressurization means and the valve, for controlling as a function of the concentration of carbon dioxide in the space one of (i) the volume of pressurized fresh air supplied to the space by the pressurization means, and (ii) the volume of air vented from the space through the valve.
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Accused Products
Abstract
A control and method for maintaining the concentration of carbon dioxide in the cabin (11) of an aircraft at a desired level. A carbon dioxide sensor (40, 41) is disposed to monitor the concentration of carbon dioxide in the cabin of the aircraft. Air drawn from the cabin at locations (24, 25) where the concentration of carbon dioxide is relatively higher than at other locations (31, 32) is selectively vented overboard or recirculated in response to the concentration of carbon dioxide in the cabin. As more air is vented overboard to maintain the cabin at a desired level of carbon dioxide concentration, an air pack compensates by supplying additional pressurized fresh air to the cabin. Should the cabin pressure drop below a minimum set point limit, the control causes less air to be vented overboard, irrespective of the carbon dioxide concentration. In another embodiment, cabin pressure is controlled between predetermined limits, and so long as the pressure remains between those limits, additional pressurized fresh air is provided if the level of carbon dioxide increases beyond a predetermined limit.
47 Citations
22 Claims
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1. Apparatus for controlling the ventilation of a pressurized enclosed space, comprising:
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(a) a carbon dioxide sensor disposed so as to monitor carbon dioxide concentration in the enclosed space; (b) a valve disposed in a fluid path through which air drawn from the space is selectively vented from the space or recirculated back into it; (c) air pack means for supplying fresh pressurized air to the space; and (d) control means, connected to the carbon dioxide sensor, the pressurization means and the valve, for controlling as a function of the concentration of carbon dioxide in the space one of (i) the volume of pressurized fresh air supplied to the space by the pressurization means, and (ii) the volume of air vented from the space through the valve. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. In a system for maintaining a pressurized enclosed space at a desired air pressure, including:
- means for recirculating back into the enclosed space air drawn from the space at a plurality of locations, the air drawn from at least one or more locations being relatively higher in carbon dioxide concentration than air drawn from one or more other locations; and
means for supplying pressurized air that is a mixture of fresh air and recirculated air to the enclosed space to maintain it at a desired pressure, apparatus for controlling the ventilation of the space, comprising;(a) means for sensing carbon dioxide and for producing a signal indicative of the concentration thereof in the enclosed space; (b) means connected to receive the signal and responsive thereto, for causing one of (i) a relatively greater volume of air tobe drawn from the one or more locations where the air is relatively higher in carbon dioxide concentration and vented from the space rather than recirculated and mixed into the pressurized supply air, and (ii) the means for supplying pressurized air to supply relatively more fresh air to the space, if the concentration of carbon dioxide indicated by the signal exceeds a predetermined level. - View Dependent Claims (11, 12, 13, 14)
- means for recirculating back into the enclosed space air drawn from the space at a plurality of locations, the air drawn from at least one or more locations being relatively higher in carbon dioxide concentration than air drawn from one or more other locations; and
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15. A method for maintaining an enclosed space at a desired pressure while controlling the concentration of carbon dioxide in a pressurized airstream supplied to the space, the airstream supplied thereto being a mixture of fresh air and of recirculated air drawn from a first and a second location in the space characterized by a relatively higher concentration of carbon dioxide in the first location than in the second, comprising the steps of:
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(a) monitoring the concentration of carbon dioxide in the enclosed space; (b) monitoring the pressure in the enclosed space; (c) in response to the monitored pressure, increasing the proportion of fresh air in the airstream supplied to the space relative to the recirculated air, to make up for the air vented from the enclosed space; and (d) if the monitored concentration of carbon dioxide in the space exceeds a predetermined level, causing one of (i) more of the air drawn from the first location to be vented outside, and (ii) an increase in the proportion of fresh air in the airstream supplied to the space. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification