Optical gas sensor with enriching polymer
First Claim
1. A gas measurement sensor using electromagnetic radiation for detecting a selected gas in a test medium, said sensor comprising:
- a transmission path for receiving a first electromagnetic radiation with at least one selected wavelength; and
a measuring medium circumferentially coupling to said transmission path so that said first electromagnetic radiation is propagated circumferentially into said measuring medium, said measuring medium including a material for enhancing the concentration of said selected gas in said measuring medium relative to the concentration of said gas in said test medium when said sensor is immersed in said test medium.
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Accused Products
Abstract
A gas sensor using optical fiber technology to measure gas concentration in a test volume. In one embodiment, the sensor incorporates a gas enriching polymer which absorbs and concentrates carbon dioxide (CO2) from the test volume surrounding the sensor. The polymer is wrapped around the core of an optical fiber which guides radiation with first selected wavelengths to the polymer. The radiation propagates into the polymer and reacts with the carbon dioxide in the polymer. Determination of CO2 concentration in the test volume is made by measuring the amount of attenuation of the radiation after reacting with the carbon dioxide in the polymer. In another embodiment, the polymer is capable of absorbing oxygen from the test volume and oxygen concentration is measured using fluorescence quenching. Being added to the polymer, a special dye reacts to radiation having selected wavelengths and produces a second radiation with wavelengths which are different from the selected wavelengths and which are absorbed by oxygen. Determination of oxygen concentration in the test volume is made by measuring the degree of attenuation of the second radiation after reacting with the oxygen in the polymer.
25 Citations
24 Claims
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1. A gas measurement sensor using electromagnetic radiation for detecting a selected gas in a test medium, said sensor comprising:
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a transmission path for receiving a first electromagnetic radiation with at least one selected wavelength; and a measuring medium circumferentially coupling to said transmission path so that said first electromagnetic radiation is propagated circumferentially into said measuring medium, said measuring medium including a material for enhancing the concentration of said selected gas in said measuring medium relative to the concentration of said gas in said test medium when said sensor is immersed in said test medium. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A gas measurement sensor using optical radiation for detecting a selected gas in a test medium, the sensor comprising:
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a measuring medium receiving a first optical radiation with at least one selected wavelength shorter than 4 μ
m, said first optical radiation propagating into said measuring medium, said measuring medium including a material for enhancing the concentration of said selected gas in said measuring medium relative to the concentration of said selected gas in said test medium when said sensor is immersed in said test medium, said measuring medium having a first end and an opposing second end;a distal-end reflecting membrane being connected to said second end of said measuring medium for reflecting said first optical radiation back through said measuring medium. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method to make a gas measuring sensor with a reflecting membrane and a first medium on a step index optical fiber which has a buffer and a cladding and a core, said method comprising the steps of:
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a. stripping said buffer and said cladding to expose said core of said fiber; b. coating said exposed core of said fiber with said first medium to make a medium-coated fiber; c. preparing a solution of 1,3-dioxole, 4,5-difluoro-2,2-bis (trifluoromehtyl)-, polymer with tetrafluoroethene; and d. coating said medium-coated fiber with 1,3-dioxole, 4,5-difluoro-2,2-bis (trifluoromehtyl)-,polymer with tetrafluoroethene by said solution of 1,3-dioxide, 4,5-difluoro-2,2-bis (trifluoromehtyl)-,polymer with tetrafluoroethene.
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24. A gas measurement sensor using electromagnetic radiation for detecting a selected gas in a test medium, said sensor comprising:
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a transmission path for receiving a first electromagnetic radiation with at least one selected wavelength, said transmission path being characterized by a first refractive index; a measuring medium coupled to said transmission path, said first electromagnetic radiation propagating into said measuring medium, said measuring medium including a material for enhancing the concentration of said selected gas in said measuring medium relative to the concentration of said selected gas in said test medium when said sensor is immersed in said test medium; and a reflecting membrane being substantially permeable to said selected gas and being connected for reflecting said first electromagnetic radiation back into said measuring medium, said reflecting membrane being characterized by a second refractive index which is less than said first refractive index.
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Specification