Radiant energy – Invisible radiant energy responsive electric signalling – Infrared responsive
Reexamination Certificate
1999-10-15
2002-04-09
Hannaher, Constantine (Department: 2878)
Radiant energy
Invisible radiant energy responsive electric signalling
Infrared responsive
C250S345000
Reexamination Certificate
active
06369387
ABSTRACT:
BACKGROUND
The increasing carbon dioxide concentration in the atmosphere and the resulting greenhouse effect and climate change have become compelling topics for scientific research. In order to understand the global carbon balance, it is necessary to determine the rate at which carbon dioxide and energy exchanges between the atmosphere and terrestrial and oceanic ecosystems. A measurement technique called “eddy covariance” has been widely used to determine these rates. The air just above the earth's surface is turbulent, and small parcels of air called “eddies” transport carbon dioxide, water vapor, and heat between the atmosphere and the surface. These transport rates can be calculated from simultaneous, high-frequency measurements of the vertical component of wind speed, the concentrations of carbon dioxide and water vapor, and the air temperature.
To measure concentrations of carbon dioxide and water vapor, a gas analyzer can be used to analyze the transmittance of light in appropriate wavelength bands through a gas sample. With some gas analyzers, a sample gas containing unknown gas concentrations of carbon dioxide and water vapor is placed in a sample cell, and a reference gas with zero or known concentrations of carbon dioxide and water vapor is placed in a reference cell. The analyzer measures the unknown gas concentrations in the sample cell from calibrated signals that are proportional to the difference between light transmitted through the sample cell and light transmitted through the reference cell.
In eddy covariance applications, ambient air that is full of dust and pollen must be moved through the analyzer at high flow rates in order for the analyzer to have the necessary frequency response. Even when the air is filtered, contamination of the sample cells is inevitable, requiring the analyzer to be returned to the factory for cleaning. This is an expensive and time-consuming process, especially when the analyzer is used in a remote location such as the Amazon basin, the north slope of Alaska, or the deserts of Africa.
There is a need, therefore, for an improved gas analyzer.
SUMMARY
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims.
By way of introduction, the preferred embodiments described below provide an improved gas analyzer that overcomes the problems described above. In one preferred embodiment, a gas analyzer is presented that focuses light beams through gas cells without reflecting the light beams off the walls of the cells. By eliminating wall reflections, dirt or debris on the walls of the cells will not result in inaccurate gas concentration measurements. In another preferred embodiment, a gas analyzer is disclosed having removable gas cells, which allows a user to easily clean the cells instead of returning a contaminated gas analyzer to service personnel for disassembly, cleaning, and re-assembly. In yet another preferred embodiment, a gas analyzer with a purged gas flow channel is described. In this preferred embodiment, purged gas flows between source and detector sections of the analyzer, ensuring that the source and detector sections are free of contaminants that can result in inaccurate gas concentration measurements. In an additional preferred embodiment, a gas analyzer is disclosed which has a heat exchanger to equilibrate the temperature of incoming air to the temperature of the analyzer's gas cells, thereby avoiding temperature-based errors in gas concentration measurements.
The preferred embodiments will now be described with reference to the attached drawings.
REFERENCES:
patent: 3270756 (1966-09-01), Dryden
patent: 3712325 (1973-01-01), Harnoncourt
patent: 3792272 (1974-02-01), Harte et al.
patent: 3948281 (1976-04-01), Strain et al.
patent: 4355234 (1982-10-01), Fertig et al.
patent: 4395632 (1983-07-01), Röss et al.
patent: 4467213 (1984-08-01), Farren
patent: 4673812 (1987-06-01), Yoneda
patent: 4738147 (1988-04-01), Tomlin
patent: 4803370 (1989-02-01), Eckles
patent: 4829183 (1989-05-01), McClatchie et al.
patent: 4885469 (1989-12-01), Yamagishi et al.
patent: 4914719 (1990-04-01), Conlon et al.
patent: 5065025 (1991-11-01), Doyle
patent: 5331409 (1994-07-01), Thurtell et al.
patent: 5332901 (1994-07-01), Eckles et al.
patent: 5340987 (1994-08-01), Eckles et al.
patent: 5457320 (1995-10-01), Eckles et al.
patent: 5468961 (1995-11-01), Gradon et al.
patent: 5640014 (1997-06-01), Sauke et al.
patent: 5747809 (1998-05-01), Eckstrom
patent: 5811812 (1998-09-01), Williams et al.
patent: 6037592 (2000-03-01), Sunshine et al.
patent: 3525346 (1987-01-01), None
patent: 199 11 260 (1999-03-01), None
patent: 0503511 (1998-05-01), None
patent: 54-13388 (1979-01-01), None
patent: 55-109948 (1980-08-01), None
patent: 59-173734 (1984-10-01), None
patent: 62-217139 (1987-09-01), None
patent: WO 98/45686 (1998-10-01), None
English-Language Abstract for DE19911260A1 (2 pages).
Partial European Search Report and Annex for EP00307471 (3 pages).
Jones et al. A Fast Response Atmospheric CO2Sensor for Eddy Correlation Flux Measurements,Atmospheric Environment, vol. 12, pp. 845-851, Pergamon Press Ltd. 1978.
Bingham et al., Development of a Miniature, Rapid-Response Carbon Dioxide Sensor, Progress Report from the NSF Ecosystem Program, The National Science Foundation, (Project DEB 77-16327), Mar. 20, 1978.
Brach et al., Open Path CO2Analyser,The Institute of Physics, vol. 6, pp. 1415-1419, 1981.
Altmann et al., Two-Mirrow Multipass Absorption Cell,Applied Optics, vol. 20, No. 6, pp. 995-999, Mar. 15, 1981.
Heikinheimo et al., An Open Path, Fast Response IR Spectrometer for Simultaneous Detection of CO2and Water Vapor Fluctuations,Journal of Atmospheric and Oceanic Technology, vol. 6, pp. 624-636, Aug. 1989.
Bingham et al., Fast-Response Sensors for Eddy Covariance Measurements of CO2and Other Middle Infrared Absorbing Gases, Private Communication, not dated.
Bingham, Gail E., A Miniature Rapid Response Sensor for Atmospheric Concentrations of Carbon Dioxide, Private Communication, not dated.
Ohtaki, Eiji and Matsui, Tetuji, Infrared Device for Simultaneous Measurement of Fluctuations of Atmospheric Carbon Dixoide and Water Vapor, Boundary-Layer Meterology 24 (1982) 109-119.
Auble, David L. and Meyers, Tilden P., An Open Path, Fast Response Infrared Absorption Gas Analyzer for H2O and CO2, Boundary-Layer Meterology 59: 243-256. 1992.
Internet Web page entitled Infrared Gas Analyzer, www.atdd.noaa.gov/irga/irga.htm, Jul. 6, 1999.
Internet Web page entitled Advance Optima Infrared Analyzer Module Uras 14, www.hub.de/world/analyse/en/optima/p_aui_01.htm, Jul. 9, 1999.
Internet Web page entitled Dynamax Inc.—ADC 2250 Series, www.dynamax.com/adc.htm, Jul. 9, 1999.
Internet Web page entitled Infra-Red Gas Analysis Systems CIRAS-1, CIRAS-2 SC & DC, www.ppsystems.com/gas2.html, Jul. 9, 1999.
Internet Web page entitled Gas Analysis Ultramat 6, www3.ad.siemens.de/ca01cache/en_3000133_b_tab0_IE4.htm, Jul. 9, 1999.
Internet Web page entitled Gas Analysis Ultramat 23, www3.ad.siemens.de/ca01cache/en_3000134_b_tab01_IE4.htm, Jul. 9, 1999.
Internet Web page entitled Gas Analysis Ultramat 5F-Ex u. 5F-2R-Ex, www3.ad.siemens.de/ca01cache/en_3000137_b_tab013IE4.htm, Jul. 9, 1999.
Internet Web page entitled Gas Analysis Ultramat/Oxymat 6, www3.ad.siemens.de/ca01cache/en_3000154_b_tab0_IE4.htm, Jul. 9, 1999.
“Infrared Gas Analyzers for CO2and CO2/H2O Measurements,” LI-COR, 15 pages (1994).
Hannaher Constantine
Israel Andrew
Li-Cor Inc.
LandOfFree
Gas analyzer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Gas analyzer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gas analyzer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2887542