EP0307625A2
Expired / Lapsed
EP
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Optical gas analyzer
Assignee: Gambro Engstrom AB
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Filing: 1988-08-12
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Granted: —
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Expires: 2008-08-12
Abstract
Abstract An optical gas analyzer comprising a source of radiation (1) and means (8) for conducting the radiation obtained from this source (1) through a gas sample and a number of optical filters (10a,10b,10c) corresponding to the number of gases analysed, each of which allows through a wavelength representative for the particular gas and especially absorbed by the same, to a number of detector (11a,11b,11c) corresponding to the number of gases analyzed. The gas analyzer described is intended primarily for the measurement of anaesthesia gases, e g halothane, isoflurane and enflurane, carbon dioxide and laughing gas and in particular in connection with anaesthization for monitoring the patient and administering the anaesthetic. The gas analyzer is characterized by means (8a,8b,8c) for the dividing up of the radiation path after passing of the gas sample for the purpose of simultaneous measurement of the gas concentrations in respective detectors.
Inventors
- 👤 Lars Erik Nilsson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 03:07
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/3504; G01N2021/3129; G01N21/314; G01N2021/3166; G01N2201/00; G01N2201/02; G01N2201/023; G01N2201/0231
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
101 words
An optical gas analyzer comprising a source of radiation (1) and means (8) for conducting the radiation obtained from this source through a gas sample and a number of optical filters (10a,10b,10c) corresponding to the number of gases analysed, each of which allows through a wavelength representative for the particular gas and especially absorbed by the same, to a number of detectors (11a,11b,11c) corresponding to the number of gases analysed, characterized by means (8a,8b,8c) for the dividing up of the radiation path after passing of the gas sample for the purpose of simultaneous measurement of the gas concentrations in respecive detectors.
Claim 2
Dependent Claim
101 words
An optical gas analyzer comprising a source of radiation (1) and means (8) for conducting the radiation obtained from this source through a gas sample and a number of optical filters (10a,10b,10c) corresponding to the number of gases analysed, each of which allows through a wavelength representative for the particular gas and especially absorbed by the same, to a number of detectors (11a,11b,11c) corresponding to the number of gases analysed, characterized by means (8a,8b,8c) for the dividing up of the radiation path after passing of the gas sample for the purpose of simultaneous measurement of the gas concentrations in respecive detectors.
Claim 3
Dependent Claim
65 words
A gas analyzer in accordance with claim 1, intended for measuring of, among other things, anaesthesia gases in inspired and/or expired air of a patient, characterized in that the said optical filters (10a,10b,10c) are chosen so that they allow through wavelengths only between 3,8-5µ and 8-14µ, as a result of which the moisture in the breathing gas is prevented from affecting the respectice measuring result.
Claim 4
Dependent Claim
59 words
A gas analyzer in accordance with claim 2, characterized in that on measuring anaesthesia gases, e g halothane, isoflurane and enflurane, a filter (10c) is chosen which is permeable for the wavelength 8,81µ, in combination with an N₂O-filter (10b) and a CO₂-filter (10a) which are permeable for wavelengths absorbed especially by these gases, in particular 3,90µ and 4,26µ respectively.
Claim 5
Dependent Claim
44 words
A gas analyzer in accordance with claim 3, characterized by means (18) for the correction of the absorption caused by N₂O as recorded by the anaesthesia detector, as a function of the measured value in the N₂O detector (11b) obtained at the same time.
Claim 6
Dependent Claim
49 words
A gas analyzer in accordance with claim 1, characterized in that the said means (8) for the division of the radiation path is constituted of a mirror arrangement which preferably divides the radiation path into a number of preferably equivalent ray bundles corresponding to the number of gases analysed.
Claim 7
Dependent Claim
47 words
A gas analyzer in accordance with anyone of the preceding claims, characterized by means for the conducting of the gas analysed through a cell or the like (3) with two windows (4,5) of for example CaF₂ (calcium fluoride) transparent for the radiation, placed in the radiation path.
Claim 8
Dependent Claim
61 words
A gas analyzer in accordance with anyone of the preceding claims, characterized by means (14,18) for keeping constant the temperature of the items, e g filters, mirrors and detectors together with holders for these items arranged in the radiation path, and preferably also keeping the gas analysed at a constant temperature above the dew point of any water vapour present therein.
Claim 9
Dependent Claim
51 words
A gas analyzer in accordance with anyone of the preceding claims, characterized by means (6,7) for the continuous conducting of the gas analysed through the radiation path and by means, e g a rotating diaphragm (2), for the regular interruption of the radiation path in order to obtain intermittent measuring values.
Claim 10
Dependent Claim
34 words
A gas analyzer in accordance with anyone of the preceding claims, characterized by means (18) for making use of measuring values obtained in a CO₂ detector for determining the end of an expiratory phase.
Claim 11
Dependent Claim
68 words
A gas analyzer in accordance with anyone of the preceding claims, characterized in that the source of radiation (1) consists of an IR-source which emits a continuous radiaton over a large wavelength range, e g thermal lamp with an envelope of quartz glass which absorbs the thermal radiation from the incandescent filament and in this way is heated so that it in turn gives off the desired radiation.
Claim 12
Dependent Claim
26 words
A gas analyzer in accordance with claim 10, characterized in that the heat source is surrounded outermost by a thin metal envelope with oxidized outer surface.
Claim 13
Dependent Claim
22 words
A gas analyzer in accordance with claim 11, characterized in that the metal envelope consist of steel or brass, preferably black-nickel-plated brass.
Claim 14
Dependent Claim
23 words
A gas analyzer in accordance with anyone of the preceding claims, characterized by a pressure gauge (21) arranged in the analyzed gas sample.
References Cited (Backward Citations)
No citation records indexed.
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