Furnace atmosphere measurement
First Claim
1. A method of determining the concentration of a species in a portion of a furnace atmosphere comprising the steps:
- (i) measuring a first intensity I1 of electromagnetic radiation in the furnace at a first wavelength λ
1;
(ii) measuring a second intensity I2 of electromagnetic radiation in the furnace at a second wavelength λ
2;
(iii) measuring a third intensity I3 of electromagnetic radiation in the furnace at a third wavelength λ
3, the third wavelength being selected to be representative of the absorption of electromagnetic radiation by the species;
(iv) calculating a fourth intensity I4 at the third wavelength using the first and second intensities, the fourth intensity being an estimate of the intensity of electromagnetic radiation in the furnace at the third wavelength absent any absorbing species in the furnace atmosphere; and
(v) using the third intensity and the fourth intensity to determine a parameter that is proportional to the concentration of absorbing species in the portion of the furnace atmosphere.
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Abstract
A method of determining the concentration of a species in a portion of a furnace atmosphere is described. The method comprises the steps of measuring first, second and third intensities of electromagnetic radiation in the furnace at first, second and third wavelengths respectively. The third wavelength is selected to be representative of absorption of electromagnetic radiation by the species. A fourth intensity of electromagnetic radiation is calculated, being an estimate of the intensity of electromagnetic radiation in the furnace at the third wavelength absent any absorbing species in the furnace atmosphere. The third intensity and the fourth intensities are used to determine a parameter that is proportional to the concentration of absorbing species in the portion of the furnace atmosphere. Apparatus for carrying out the method is also described.
12 Citations
20 Claims
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1. A method of determining the concentration of a species in a portion of a furnace atmosphere comprising the steps:
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(i) measuring a first intensity I1 of electromagnetic radiation in the furnace at a first wavelength λ
1;(ii) measuring a second intensity I2 of electromagnetic radiation in the furnace at a second wavelength λ
2;(iii) measuring a third intensity I3 of electromagnetic radiation in the furnace at a third wavelength λ
3, the third wavelength being selected to be representative of the absorption of electromagnetic radiation by the species;(iv) calculating a fourth intensity I4 at the third wavelength using the first and second intensities, the fourth intensity being an estimate of the intensity of electromagnetic radiation in the furnace at the third wavelength absent any absorbing species in the furnace atmosphere; and (v) using the third intensity and the fourth intensity to determine a parameter that is proportional to the concentration of absorbing species in the portion of the furnace atmosphere. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. Apparatus for measuring the concentration of a species in a portion of a furnace atmosphere, the species absorbing electromagnetic radiation in the furnace, the apparatus comprising:
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means for collecting electromagnetic radiation to collect electromagnetic radiation from inside the furnace; means for coupling to direct the collected electromagnetic radiation to a suitable means for measuring, the means for measuring being configured to; (i) measure a first intensity I1 of electromagnetic radiation in the furnace at a first wavelength λ
2;(ii) measure a second intensity I2 of electromagnetic radiation in the furnace at a second wavelengthλ
2;(iii) and measure a third intensity I3 of electromagnetic radiation in the furnace at a third wavelength λ
3, the third wavelength being selected to be representative of the absorption of electromagnetic radiation by the species; andmeans for computing, configured to take the output from the measuring means to determine the amount of absorption of electromagnetic radiation inside the furnace at a measurement wavelength, the measurement wavelength being selected to be representative of the absorption of electromagnetic radiation in the furnace atmosphere by the species, by calculating a fourth intensity I4 at the third wavelength using the first and second intensities, the fourth intensity being an estimate of the intensity of electromagnetic radiation in the furnace at the third wavelength absent any absorbing species in the furnace atmosphere; and using the third intensity and the fourth intensity to determine a parameter that is proportional to the concentration of absorbing species in the portion of the furnace atmosphere. - View Dependent Claims (19)
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20. A method of determining the concentration of a species in a portion of a furnace atmosphere without using a separate background trace, comprising the steps:
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(i) measuring a first intensity I1 of electromagnetic radiation in the furnace at a first wavelength λ
1 ;(ii) measuring a second intensity I2 of electromagnetic radiation in the furnace at a second wavelength λ
2;(iii) measuring a third intensity I3 of electromagnetic radiation in the furnace at a third wavelength λ
3, the third wavelength being selected to be representative of the absorption of electromagnetic radiation by the species;(iv) calculating a fourth intensity I4 at the third wavelength using the first and second intensities, the fourth intensity being an estimate of the intensity of electromagnetic radiation in the furnace at the third wavelength absent any absorbing species in the furnace atmosphere; and (v) using the third intensity and the fourth intensity to determine a parameter that is proportional to the concentration of absorbing species in the portion of the furnace atmosphere.
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Specification