Oxygen monitoring method and apparatus
First Claim
1. A method of monitoring oxygen in oxygen-enriched air delivered by an aircraft on-board oxygen generating system comprising the steps of:
- supplying a sample of oxygen-enriched air to solid amperometric sensor means whereby a non-linear current signal having a logarithmic relationship with oxygen concentration is output by said sensor means;
converting the current signal output by said sensor means to a voltage signal;
converting the voltage signal from analog to digital signal,processing the digital signal in signal processing means storing an oxygen diffusion equation in the form of a look-up table;
and outputting a linear oxygen percentage concentration signal for control and/or warning purposes.
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Accused Products
Abstract
The oxygen content of oxygen-enriched air is monitored by a solid electrolyte amperometric sensor which does not require a reference gas for comparison with the oxygen-enriched air. When oxygen-enriched air is supplied to the sensor a current signal is output by the sensor. The current signal is converted to a voltage signal which is processed by a signal processor storing an oxygen diffusion equation in the form of a look-up table to obtain an oxygen percentage concentration signal. An oxygen partial pressure signal may be obtained by supplying ambient pressure signals from an ambient pressure sensor to the signal processor for multiplication with the oxygen concentration signal.
58 Citations
14 Claims
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1. A method of monitoring oxygen in oxygen-enriched air delivered by an aircraft on-board oxygen generating system comprising the steps of:
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supplying a sample of oxygen-enriched air to solid amperometric sensor means whereby a non-linear current signal having a logarithmic relationship with oxygen concentration is output by said sensor means; converting the current signal output by said sensor means to a voltage signal; converting the voltage signal from analog to digital signal, processing the digital signal in signal processing means storing an oxygen diffusion equation in the form of a look-up table; and outputting a linear oxygen percentage concentration signal for control and/or warning purposes. - View Dependent Claims (2, 3, 4)
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- 5. Apparatus for monitoring oxygen in oxygen-enriched air delivered by an aircraft on-board oxygen generating system comprising solid electrolyte amperometric sensor means, means for supplying a sample of oxygen-enriched air to said sensor means whereby a non-linear current signal having a logarithmic relationship with oxygen concentration is output by said sensor means, and means for converting the current signal to a voltage signal, means for converting the voltage signal from analog to digital signal, means for delivering the digital signal to signal processing means storing an oxygen diffusion equation in the form of a look-up table, said signal processing means being adapted to process the digital signal and output a linear oxygen percentage concentration signal for control and/or warning purposes.
Specification