APPARATUS AND METHOD FOR CONTINUOUSLY DETECTING OXYGEN IN A GAS STREAM

• US 3,725,658 A
• Filed: 01/18/1971
• Issued: 04/03/1973
• Est. Priority Date: 01/18/1971
• Status: Expired due to Term

• Current Assignee: Charles C. Stanley, John L. Kropp
• Original Assignee: Charles C. Stanley, John L. Kropp
• Inventors: Stanley, Charles C., Kropp, John L.
• Primary Examiner(s): Borchelt, Archie R.
• Application Number:
  US05/106,987
• Time in Patent Office: 806 Days
• Field of Search: 250/71R 204/1,195 252/301.2,301.3 23/230,259
• US Class Current: 250/364
• CPC Class Codes: G01N 2021/6432 Quenching
• CPC Class Codes: G01N 21/6428 Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" in vivo A61B5/00; immunoassay G01N33/53
• CPC Class Codes: Y10T 436/177692 Oxides of nitrogen
• CPC Class Codes: Y10T 436/178459 Only nitrogen dioxide
• CPC Class Codes: Y10T 436/186 Sulfur dioxide
• CPC Class Codes: Y10T 436/207497 Molecular oxygen

Abstract

An apparatus and method for continuously detecting oxygen in a carrier gas stream. The apparatus employs a sensor film comprising a fluorescent material emitting from 3000 - 8000 A, dissolved in a carrier or solvent, the film being supported on a suitable substrate. Exciting radiation of about 2000 - 6500 A is applied to the film causing the fluorescent material to emit. Oxygen contained in the gas stream is rapidly dissolved into, and purged out of the film. The dissolved oxygen will quench the fluorescent emission, and the extent of quenching is proportional to the oxygen content of the gas stream. The dissolving and purging cycle occurs with sufficient speed to enable the oxygen analysis of breath to be determined on a real time basis.

Claims

2. An apparatus for continuously detecting oxygen in a gas stream which comprises:

a sensor comprising a solvent and a fluorescent material dissolved therein;

the fluorescent material having a fluorescent lifetime of about 1 X 10 9 to 1 X 10 6 seconds;

said fluorescent material being capable of absorbing exciting radiation in the range of about 2000 - 6500 A and emitting in the range of about 3000 -8000 A;

said fluorescent material having a fluorescent yield greater than about 1 percent;

said sensor being supported on the outer side of a substrate as a stable and uniform film of about 2-80 microns thick;

the response time of said film to equilibration of oxygen between the film and the gas above the film being a maximum of 0.1 seconds;

a source of radiation to excite said film;

said exciting radiation emitting in the 2000 - 6500 A range;

the fluorescence of said fluorescent material being quenchable by oxygen proportionally to the amount of oxygen absorbed in said film;

means to detect the changes in fluorescence of said fluorescent material, said changes being proportional to the amount of oxygen present in the gas stream; and

means to record said changes in fluorescence.

3. An apparatus for continuously detecting in a gas stream, a gas selected from the class of compounds consisting of oxygen, SO2, NO and NO3 which comprises:

a sensor comprising a solvent and a fluorescent material dissolved therein;

the fluorescent material having a fluorescent lifetime of about 1 X 10 9 to 1 X 10 6 seconds;

said fluorescent material being capable of absorbing exciting radiation in the range of about 2000 - 6500 A and emitting in the range of about 3000 -8000 A;

said fluorescent material having a fluorescent yield greater than about 1 percent;

said sensor being supported on the outer side of a substrate as a stable and uniform film of about 2-80 microns thick;

the response time of said film to equilibration of said gas between the film and the gas above the film being a maximum of 0.1 seconds;

a source of radiation to excite said film;

said exciting radiation emitting in the 2000 - 6500 A range;

the fluorescence of said fluorescent material being quenchable by said gas proportionally to the amount of said gas absorbed in said film;

means to detect the changes in fluorescence of said fluorescent material, said changes being proportional to the amount of said gas present in the gas stream; and

means to record said changes in fluorescence.

4. The apparatus of claim 2 in which the solvent is selected from the class consisting of mineral oil, decalin, glycerol, Tetrahydrofuran, benzene and hexane.

5. The apparatus of claim 2 in which the fluorescent material is selected from the class consisting of pyrene, coronene, p-terphenyl and ovalene.

6. The apparatus of claim 2 in which the fluorescent yield of said compound is greater than about 10 percent.

7. A process for continuously detecting oxygen in a gas stream which comprises:

passing said gas stream over a sensor supported on the outer side of a substrate as a stable and uniform film;

said sensor film comprising a fluorescent material and a solvent therefor;

said fluorescent material having a fluorescent lifetime of at least 1 X 10 9 seconds;

said fluorescent material being capable of absorbing exciting radiation in the range of about 2000 - 6500 A and emitting in the range of about 3000 - 8000 A;

irradiating said film with exciting radiation in the 2000 - 6500 A range;

the fluorescence of said fluorescent material being quenchable by oxygen in proportion to the amount of oxygen in said film;

equilibrating the oxygen between the film and the gas stream above it;

detecting the changes in fluorescence of said fluorescent material, said changes being proportional to the amount of oxygen present in the gas stream; and

recording said changes in fluorescence.

8. A process for continuously detecting oxygen in a gas stream which comprises;

passing said gas stream over a sensor supported on the outer side of a substrate as a stable and uniform film;

said sensor film comprising a fluorescent material and a solvent therefor;

said fluorescent material having a fluorescent life-time of about 1 X 10 6 to 1 X 10 9 seconds;

said fluorescent material being capable of absorbing exciting radiation in the range of about 3000 - 8000 A;

irradiating said film with exciting radiation in the 2000 - 6500 A range;

the fluorescence of said fluorescent material being quenchable by oxygen in proportion to the amount of oxygen in said film;

the response time of said film to equilibration of oxygen between the film and the gas stream above it being at most 0.1 seconds;

detecting the changes in fluorescent of said fluorescent material, said changes being proportional to the amount of oxygen present in the gas stream; and

recording said changes in fluorescence.

9. A process for continuously detecting in a gas stream, a gas selected from the class consisting of oxygen, SO2, NO and No3 which comprises:

passing said gas stream over a sensor supported on the outer side of a substrate as a stable and uniform film;

said sensor film comprising a fluorescent material and a solvent therefor;

said fluorescent material having a fluorescent life-time of about 1 X 10 6 to 1 X 10 9 seconds;

said fluorescent material being capable of absorbing exciting radiation in the range of about 3000 - 8000 A;

irradiating said film with exciting radiation in the 2000 - 6500 A range;

the fluorescence of said fluorescent material being quenchable by said gas in proportion to the amount of said gas in said film;

the response time of said film to equilibration of said gas between the film and the gas stream above it being at most 0.1 seconds;

detecting the changes in fluorescent of said fluorescent material, said changes being proportional to the amount of said gas present in the gas stream; and

recording said changes in fluorescence.