Apparatus for high oxygen concentration measurement using limiting current oxygen sensor
AssigneeLitton Systems, Inc.
InventorTuan Quoc Cao
Life of this patent
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Abstract
A gas analysis apparatus using multiple orifices of preselected sizes to attain a calculated gas mixing ratio for diluting an oxygen sample to a concentration less than 95% prior to application to a limiting current oxygen sensor. The apparatus comprises a regulator for regulating the pressures of incoming flows of air and oxygen sample to be measured, a valve for allowing the concentration of the air sample to oxygen sample to be measured, and a system for calculating the air sample/oxygen sample mixing ratio based on the known air sample concentration and then, based on the known air concentration and calculated mixing ratio, calculating the unknown sample concentration from the output of the oxygen sensor.
Claims8
An gas analysis apparatus for measuring high concentrations of oxygen, comprising:
- a sample port for receiving a sample flow of one of either a calibration gas having a known oxygen concentration (Cc) or a sample gas having an unknown oxygen concentration (Cs) of up to 100%;
- an ambient air port for receiving an air flow of ambient air having predetermined oxygen concentration (Ca);
- a limiting current oxygen sensor having inputs connected to said sample port and said ambient air port for receiving a diluted oxygen mixture of said sample flow and said air flow in a known proportion and in the event said sample flow is calibration gas generating a calibration reading (Cr) indicating oxygen content in said mixture of calibration gas and air flow, and in the event said sample flow is sample gas generating a mixture concentration reading (Cm) indicating oxygen content in said mixture of sample gas and air flow;
- and
- a controller connected to said limiting current oxygen sensor for receiving and storing said known oxygen concentration (Cc) of said calibration gas, said predetermined oxygen concentration (Ca) of said air flow, said calibration reading (Cr) and said mixture concentration reading (Cm) and in response calculating said unknown oxygen concentration (Cs) in said sample gas.
A gas analyser method for measuring high oxygen concentrations of up to 100% in a sample gas, using a limiting current oxygen sensor, comprising the steps of:
- applying a with mixture known proportions of calibration gas having a known oxygen concentration (Cc) and ambient air having a known oxygen concentration (Ca) to said limiting current oxygen sensor which, in response generates a calibration reading (Cr) indicating oxygen content in said mixture of calibration gas and air;
- storing said known oxygen concentrations (Cc and Ca) and said calibration reading (Cr);
- applying a diluted oxygen mixture of said sample gas and ambient air in a known proportion to said limiting current oxygen sensor which, in response generates a mixture concentration reading (Cm) indicating oxygen content in said mixture of sample gas and air;
- storing said mixture concentration reading (Cm);
- retrieving said known oxygen concentrations (Cc and Ca), said calibration reading (Cr) and said mixture concentration reading (Cm);
- and
- calculating oxygen concentration (Cs) in said sample gas as follows:
- ##EQU3##
Dependencies are inferred from the claim text.