Sensor assembly and method for measuring nitrogen dioxide
First Claim
1. A sensor assembly for use in a patient breathing system for providing real-time optical absorption analysis of the NO2 content of the breathing gases of the breaths of a subject and providing real time analysis of the NO content of the breathing gases of the breaths of a subject, said sensor assembly comprising:
- a semiconductor radiation source emitting radiation having a emission spectrum with a maximum wavelength of about 600 nm, the radiation source being operated at a sampling frequency of at least about 10 Hz;
a sample chamber having an inlet conduit for supplying a flow of breathing gases during the breaths of the subject through the chamber, the radiation from said radiation source passing through the gas in said sample chamber, said sample chamber having an outlet conduit for passing the breathing gases from said sample chamber;
a detector for receiving radiation passed through the breathing gases flowing through in said sample chamber and for providing an output signal indicative of the NO2 content of the breathing gases in said sample chamber, the detector providing the output signal in a response time of about 200 ms, such that the sensor assembly provides the output signal in real-time with respect to the breaths of the subject; and
an NO gas sensor coupled to said outlet conduit for providing a real time measurement of the NO content of the breathing gases.
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Abstract
A sensing apparatus and method for use in the optical absorption analysis of the NO2 content of a gas sample. The apparatus and method employ radiation from a semiconductor radiation source. The emission spectrum of the radiation has a maximum wavelength of about 600 nm, preferably 380-520 nm. The radiation is passed through the gas sample and sensed by a detector to provide an output signal indicative of the NO2 content of the gas sample. A pair of alternately energized radiation sources may also be used. The sensor apparatus and method may be employed in conjunction with other gas sensing apparatus and methods, such as IR CO2 measurement or NO sensing.
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Citations
65 Claims
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1. A sensor assembly for use in a patient breathing system for providing real-time optical absorption analysis of the NO2 content of the breathing gases of the breaths of a subject and providing real time analysis of the NO content of the breathing gases of the breaths of a subject, said sensor assembly comprising:
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a semiconductor radiation source emitting radiation having a emission spectrum with a maximum wavelength of about 600 nm, the radiation source being operated at a sampling frequency of at least about 10 Hz;
a sample chamber having an inlet conduit for supplying a flow of breathing gases during the breaths of the subject through the chamber, the radiation from said radiation source passing through the gas in said sample chamber, said sample chamber having an outlet conduit for passing the breathing gases from said sample chamber;
a detector for receiving radiation passed through the breathing gases flowing through in said sample chamber and for providing an output signal indicative of the NO2 content of the breathing gases in said sample chamber, the detector providing the output signal in a response time of about 200 ms, such that the sensor assembly provides the output signal in real-time with respect to the breaths of the subject; and
an NO gas sensor coupled to said outlet conduit for providing a real time measurement of the NO content of the breathing gases. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A sensor assembly for use in a patient breathing system for providing real-time optical absorption analysis of the NO2 content of the breathing gases of the breaths of a subject, said sensor assembly comprising:
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a first semiconductor radiation source emitting radiation having a emission spectrum with a maximum wavelength of about 600 nm;
a sample chamber to which is supplied a flow of breathing gases during the breaths of the subject, the NO2 content of the breathing gases so supplied being measured by said sensor assembly, the radiation from said first radiation source passing through the gas in said sample chamber;
a detector for receiving radiation passed through the breathing gases in said sample chamber; and
a second semiconductor radiation source providing radiation for passage through said sample chamber for receipt by said detector, the wavelength of the radiation provided by said second radiation source being such as to minimize absorption of the radiation by nitrogen dioxide, said first and second radiation sources being alternately energized at a sampling frequency;
said detector providing an output signal formed by the alternative energization of said radiation sources indicative of the NO2 content of the breathing gases in said sample chamber in real-time with respect to the breaths of the subject. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A method for determining the real-time NO2 and NO content of the breathing gases of the breaths of a subject comprising the steps of:
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providing a flow of breathing gases during the breaths of the subject through a sample chamber;
passing radiation from a semiconductor radiation source through the breathing gases in the sample chamber, said radiation having an emission spectrum with a maximum wavelength of about 600 nm;
operating the radiation source at a sampling frequency of at least about 10 Hz;
sensing the radiation exiting the breathing gases;
determining the NO2 content of the breathing gases from the optical spectral absorption characteristics of the sensed radiation resulting from the presence and amount of NO2 in the breathing gases in a response time of about 200 ms such that the NO2 content of the gas sample can be determined in real-time with respect to the breaths of the subject; and
passing breathing gas discharged from the sample chamber through an NO gas sensor providing real time measurement of the NO content of the breathing gases. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
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56. A method for real-time determination of the NO2 content of the breathing gases of the breaths of a subject, said method comprising the steps of:
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providing a flow of breathing gases during the breaths of the subject through a sample chamber;
passing radiation from a first semiconductor radiation source through the breathing gases in the sample chamber, said radiation from said first source having an emission spectrum with a maximum wavelength of about 600 nm;
passing radiation from a second semiconductor radiation source through the breathing gases in the sample chamber, the wavelength of the radiation from said second source being such as to minimize absorption of the radiation by nitrogen dioxide;
the first and second radiation sources being alternately operated at a selected sampling frequency;
sensing the radiation exiting the breathing gases as a result of the alternative operation of the radiation sources; and
determining the NO2 content of the breathing gases from the sensed exiting radiation in real-time with respect to the breaths of the subject. - View Dependent Claims (57, 58, 59, 60, 61, 62, 63, 64, 65)
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Specification