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WO1992003724A1 - Gas analyser - Google Patents

Gas analyser Download PDF

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Publication number
WO1992003724A1
WO1992003724A1 PCT/AU1991/000367 AU9100367W WO9203724A1 WO 1992003724 A1 WO1992003724 A1 WO 1992003724A1 AU 9100367 W AU9100367 W AU 9100367W WO 9203724 A1 WO9203724 A1 WO 9203724A1
Authority
WO
WIPO (PCT)
Prior art keywords
chamber
pulse
gas
gas analyser
mixture
Prior art date
Application number
PCT/AU1991/000367
Other languages
French (fr)
Inventor
Robert Geoffrey Tyers
Original Assignee
The Commonwealth Industrial Gases Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Commonwealth Industrial Gases Limited filed Critical The Commonwealth Industrial Gases Limited
Publication of WO1992003724A1 publication Critical patent/WO1992003724A1/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/02—Analysing fluids
    • G01N29/024—Analysing fluids by measuring propagation velocity or propagation time of acoustic waves
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/10—Preparation of respiratory gases or vapours
    • A61M16/104—Preparation of respiratory gases or vapours specially adapted for anaesthetics
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/10—Preparation of respiratory gases or vapours
    • A61M16/1005—Preparation of respiratory gases or vapours with O2 features or with parameter measurement
    • A61M2016/102—Measuring a parameter of the content of the delivered gas
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/10—Preparation of respiratory gases or vapours
    • A61M16/1005—Preparation of respiratory gases or vapours with O2 features or with parameter measurement
    • A61M2016/102—Measuring a parameter of the content of the delivered gas
    • A61M2016/1025—Measuring a parameter of the content of the delivered gas the O2 concentration
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/021—Gases
    • G01N2291/0212—Binary gases
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/044—Internal reflections (echoes), e.g. on walls or defects
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/10—Number of transducers
    • G01N2291/101—Number of transducers one transducer

Definitions

  • the present invention relates to gas analysers for determining the composition of gas mixtures and, in particular, to a device for use in monitoring mixtures of two gaseous components for an undesirable level of one component.
  • gaseous component is intended to embrace a single gas or a gas mixture of known composition.
  • the invention finds particular application in the field of medicine for use in monitoring analgesic gas mixtures for low levels of oxygen. Although the invention has application to other fields of use, it will be described herein with reference to this application, that is as a low oxygen monitor. Typically in these instances the two gases are oxygen and nitrous oxide.
  • a gas analyser for determining respective proportions of two gaseous components in a mixture, said analyser including a chamber having an inlet and an outlet for said mixture positioned to provide a flow of said mixture through said chamber, transmitter means to transmit an ultrasonic pulse, receiver means to receive said pulse, - and means to provide a measure of the proportions of said gaseous components from the transit time of a pulse transmitted by said transmitter and received by said receiver means.
  • both the transmitter means and the receiver means are provided by a single ultrasonic transducer positioned at one of the ends of said chamber and the pulse received by the receiver means is an echo of the pulse transmitted by the transmitter means.
  • the chamber is cylindrical.
  • the means to provide a measure of the composition of the mixture also preferably includes means to compare the composition with predetermined limits for producing alarm signals in the event that the composition falls outside those limits.
  • the invention allows the speed of sound in a mixture of two known gaseous components to be determined. From the knowledge of the velocity of sound in each of the constituent gas components can be determined the proportion of each in a mixture when the velocity of sound in the mixture is measured. When one or both component gases is itself a mixture, the composition in terms of those component gases can still be determined if the composition of each is known and constant.
  • the velocity of sound in a gas mixture is a function only of the mean molecular weight of the mixture.
  • FIG. 1 is a block diagram of a gas analyser according to the invention.
  • Figure 2 is a schematic diagram showing the gas analyser of Figure 1 incorporated in an anaesthetic machine.
  • the gas analyser 1 includes an elongate cylindrical chamber 2.
  • An ultrasonic transducer 5 is located at one of the ends and the chamber includes an inlet 6 and an outlet 7 for gas mixtures.
  • the inlet and outlet are located at opposite ends of the chamber to ensure that the composition of gas in the entire chamber reflects the composition of the gas flowing into the inlet.
  • the gas analyser is therefore able to monitor the composition of time varying gas mixtures.
  • a temperature sensor 4 provides a measure of temperature of the gas in the chamber.
  • An oscillator 8 of conventional design generates a 49 kHz signal which is gated by a 1.5 millisecond pulse 9 initiated from a microprocessor 10.
  • the resulting 49 kHz burst is amplified 11 and fed to the transducer.
  • a pulse of sound 12 travels along the chamber through the gas mixture and echoes from the far end, returning to the transducer.
  • the corresponding electrical signal is gated 13 to distinguish it from the original pulse and detected by a receiver 14 which feeds the signal back to the microprocessor.
  • the microprocessor registers the delay between the original pulse and the echo and therefore, given the dimensions of the chamber, can calculate the speed of sound in the gas mixture and therefore its mean molecular weight. Any compensation for the effects of changes in temperature may be applied at this time by virtue of the measurement from the temperature sensor 4.
  • the dimensions of the chamber are constrained by the duration of the ultrasonic pulse and the speed of sound.
  • a chamber 300 mm long and 40 mm in diameter allows the leading edge of the transmitted pulse to return to the transducer in approximately 2 ms. This permits the echo pulse to be distinguished from the original pulse.
  • the percentage of either or both constituents may therefore be calculated and displayed, for example, on a digital readout 15.
  • the transit time may be compared with predetermined values and a visual 16 or audible 17 alarm initiated when the transit time falls outside those values. Where an audible alarm is provided a method of silencing the alarm is desirable. Accordingly, a mute switch 18 is provided. Further features of the preferred embodiment, not shown in Figure 1, include a power supply with rechargeable battery and automatic battery management circuitry. In accordance with relevant standards, the gas analyser provides an indication that the battery is adequately charged for standby use.
  • Industrial Applicability Figure 2 illustrates the application of the gas analyser as a low oxygen monitor in an anaesthetic machine.
  • regulated oxygen 19 nitrous oxide 20 and air 21 are variously mixed for supply to the fresh gas outlet 22.
  • the machine allows combination of either air or nitrous oxide with oxygen and further allows the vapour of an anaesthetic agent to be added to the gas mixture by means of a vapouriser 23.
  • the pressure of the oxygen supply is used to control the supply of the nitrous oxide through valve 24. If no oxygen is available, no nitrous oxide flows.
  • the machine can be switched off by interrupting the oxygen supply at 26 in which case interruption of the air supply can be effected by valve 25.
  • the anaesthetic machine is augmented by addition of the gas analyser of the invention 27.
  • the cylindrical chamber 28 is connected in line with the gas mixture, before the vapouriser, and the transducer is wired to the gas analyser.
  • Pressure switches 29, 30 and 31 monitor oxygen, nitrous oxide and air pressure respectively and a solenoid/whistle 32 is connected to the oxygen supply so that the gas analyser can initiate an audible signal in the event of error conditions.
  • a safety valve 33 prevents overpressure in the gas mixture and it should be noted that, as an additional safety feature, the gas analyser does not control the operation of the anaesthetic machine and can in fact be added to existing machines with a minimum of wiring and plumbing.

Landscapes

  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • General Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biomedical Technology (AREA)
  • Emergency Medicine (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Hematology (AREA)
  • Engineering & Computer Science (AREA)
  • Animal Behavior & Ethology (AREA)
  • Pulmonology (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Anesthesiology (AREA)
  • Acoustics & Sound (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

A gas analyser (1) for determining the respective proportions of the components of a mixture of two gases, includes a chamber (2) having an inlet (6) and an outlet (7) allowing the gas mixture to flow through the chamber. The analyser also includes tansmitter means (5) and receiver means (5) for respectively tansmitting and receiving ultrasonic pulses (12) and means to provide a measure of the proportions of the gaseous components from the transit time of a pulse transmitted by the transmitter means and received by the receiver means.

Description

Title: GAS ANALYSER
Technical Field
The present invention relates to gas analysers for determining the composition of gas mixtures and, in particular, to a device for use in monitoring mixtures of two gaseous components for an undesirable level of one component. As used herein the term gaseous component is intended to embrace a single gas or a gas mixture of known composition.
The invention finds particular application in the field of medicine for use in monitoring analgesic gas mixtures for low levels of oxygen. Although the invention has application to other fields of use, it will be described herein with reference to this application, that is as a low oxygen monitor. Typically in these instances the two gases are oxygen and nitrous oxide. Background Art
Previous methods of determining oxygen concentration have relied on chemical cells. These devices have the disadvantage of finite life due to cell consumption and, furthermore, have to be constantly recalibrated against inherent drift. Another method of determining the concentration of oxygen is the so-called paramagnetic analyser. Unlike chemical cells, this is a non-consumable device. It is, however, very expensive because of the reguired precision of its mechanical components.
Disclosure of the Invention
It is an object of the present invention to overcome or at least ameliorate the disadvantages of the prior art.
Accordingly, there is provided a gas analyser for determining respective proportions of two gaseous components in a mixture, said analyser including a chamber having an inlet and an outlet for said mixture positioned to provide a flow of said mixture through said chamber, transmitter means to transmit an ultrasonic pulse, receiver means to receive said pulse, - and means to provide a measure of the proportions of said gaseous components from the transit time of a pulse transmitted by said transmitter and received by said receiver means.
Preferably, both the transmitter means and the receiver means are provided by a single ultrasonic transducer positioned at one of the ends of said chamber and the pulse received by the receiver means is an echo of the pulse transmitted by the transmitter means.
Preferably also, the chamber is cylindrical. The means to provide a measure of the composition of the mixture also preferably includes means to compare the composition with predetermined limits for producing alarm signals in the event that the composition falls outside those limits.
The invention allows the speed of sound in a mixture of two known gaseous components to be determined. From the knowledge of the velocity of sound in each of the constituent gas components can be determined the proportion of each in a mixture when the velocity of sound in the mixture is measured. When one or both component gases is itself a mixture, the composition in terms of those component gases can still be determined if the composition of each is known and constant.
It is known that the velocity of sound u, in a gas is proportional to the absolute temperature of the gas, T, and its molecular weight, M, in the following relationship: u α (T/M)0'5
The following table illustrates typical values of sound velocities at a constant temperature of 293°K: GAS VELOCITY OF SOUND (MEAN) MOLECULAR WEIGHT
AIR 344 m/s 28.8
OXYGEN 326 m/s 32.0
NITROUS OXIDE 278 m/s 44.01
At a constant temperature the velocity of sound in a gas mixture is a function only of the mean molecular weight of the mixture.
Naturally, in practice a method of temperature compensation is required to allow the system to operate accurately over a range of ambient temperatures. Brief Description of the Drawinqs
A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
Figure 1 is a block diagram of a gas analyser according to the invention; and
Figure 2 is a schematic diagram showing the gas analyser of Figure 1 incorporated in an anaesthetic machine.
Best Mode for Carrying Out the Invention
Referring now to Figure 1, the gas analyser 1 includes an elongate cylindrical chamber 2. An ultrasonic transducer 5 is located at one of the ends and the chamber includes an inlet 6 and an outlet 7 for gas mixtures. The inlet and outlet are located at opposite ends of the chamber to ensure that the composition of gas in the entire chamber reflects the composition of the gas flowing into the inlet. The gas analyser is therefore able to monitor the composition of time varying gas mixtures. In addition a temperature sensor 4 provides a measure of temperature of the gas in the chamber.
An oscillator 8 of conventional design generates a 49 kHz signal which is gated by a 1.5 millisecond pulse 9 initiated from a microprocessor 10. The resulting 49 kHz burst is amplified 11 and fed to the transducer. A pulse of sound 12 travels along the chamber through the gas mixture and echoes from the far end, returning to the transducer. The corresponding electrical signal is gated 13 to distinguish it from the original pulse and detected by a receiver 14 which feeds the signal back to the microprocessor.
The microprocessor registers the delay between the original pulse and the echo and therefore, given the dimensions of the chamber, can calculate the speed of sound in the gas mixture and therefore its mean molecular weight. Any compensation for the effects of changes in temperature may be applied at this time by virtue of the measurement from the temperature sensor 4.
The dimensions of the chamber are constrained by the duration of the ultrasonic pulse and the speed of sound. A chamber 300 mm long and 40 mm in diameter allows the leading edge of the transmitted pulse to return to the transducer in approximately 2 ms. This permits the echo pulse to be distinguished from the original pulse. The percentage of either or both constituents may therefore be calculated and displayed, for example, on a digital readout 15. Alternatively, the transit time may be compared with predetermined values and a visual 16 or audible 17 alarm initiated when the transit time falls outside those values. Where an audible alarm is provided a method of silencing the alarm is desirable. Accordingly, a mute switch 18 is provided. Further features of the preferred embodiment, not shown in Figure 1, include a power supply with rechargeable battery and automatic battery management circuitry. In accordance with relevant standards, the gas analyser provides an indication that the battery is adequately charged for standby use.
Industrial Applicability Figure 2 illustrates the application of the gas analyser as a low oxygen monitor in an anaesthetic machine. In such a machine, regulated oxygen 19, nitrous oxide 20 and air 21 are variously mixed for supply to the fresh gas outlet 22. The machine allows combination of either air or nitrous oxide with oxygen and further allows the vapour of an anaesthetic agent to be added to the gas mixture by means of a vapouriser 23. The pressure of the oxygen supply is used to control the supply of the nitrous oxide through valve 24. If no oxygen is available, no nitrous oxide flows. The machine can be switched off by interrupting the oxygen supply at 26 in which case interruption of the air supply can be effected by valve 25.
The anaesthetic machine is augmented by addition of the gas analyser of the invention 27. The cylindrical chamber 28 is connected in line with the gas mixture, before the vapouriser, and the transducer is wired to the gas analyser. Pressure switches 29, 30 and 31 monitor oxygen, nitrous oxide and air pressure respectively and a solenoid/whistle 32 is connected to the oxygen supply so that the gas analyser can initiate an audible signal in the event of error conditions. A safety valve 33 prevents overpressure in the gas mixture and it should be noted that, as an additional safety feature, the gas analyser does not control the operation of the anaesthetic machine and can in fact be added to existing machines with a minimum of wiring and plumbing.
Although the invention has been described with reference to specific embodiments, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-
1. A gas analyser for determining respective proportions of two gaseous components in a mixture, characterised by the inclusion of a chamber having an inlet and an outlet for said mixture positioned to provide a flow of said mixture through said chamber, transmitter means to transmit an ultrasonic pulse, receiver means to receive said pulse, and means to provide a measure of the respective proportions of said gaseous components from the transit time of a pulse transmitted by said transmitter means and received by said receiver means.
2. A gas analyser as claimed in Claim 1, wherein the chamber is elongate and both transmitter means and receiver means are provided by a single ultrasonic transducer positioned at one of the ends of said chamber, said pulse received by said receiver means being an echo of the pulse transmitted by the transmitter means.
3. A gas analyser as claimed in Claim 1 or Claim 2, wherein the chamber is cylindrical.
4. A gas analyser as claimed in any one of the preceding claims, further comprising means to compare the determined proportions with predetermined limits for producing alarm signals in the event that the proportions fall outside those limits.
5. A gas analyser as claimed in any one of the preceding claims, wherein the longitudinal dimension of the chamber is such that the transit time of the pulse is greater than the duration of the pulse.
6. A gas analyser as claimed in any one of the preceding claims, wherein the duration of the pulse is 1.5 ms.
PCT/AU1991/000367 1990-08-17 1991-08-16 Gas analyser WO1992003724A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPK180690 1990-08-17
AUPK1806 1990-08-17

Publications (1)

Publication Number Publication Date
WO1992003724A1 true WO1992003724A1 (en) 1992-03-05

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Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5392635A (en) * 1993-12-30 1995-02-28 At&T Corp. Acoustic analysis of gas mixtures
EP0657736A1 (en) * 1993-12-07 1995-06-14 Marwal Systems Apparatus for acoustically measuring the composition of a binary liquid
EP0740923A1 (en) * 1995-05-05 1996-11-06 Siemens-Elema AB Device for transmitting information via a patient tube in an intensive care or anesthetic machine
US5625140A (en) * 1995-12-12 1997-04-29 Lucent Technologies Inc. Acoustic analysis of gas mixtures
ES2114492A1 (en) * 1996-05-22 1998-05-16 Barba Trigueros Francisco Device for detecting in the air combustible gases supplied to non-industrial residential buildings by means of ultrasound.
US5792665A (en) * 1996-05-29 1998-08-11 Morrow, Iii; Donald W. Oxygen sensing method and hand held analyzer therefore
US5900552A (en) * 1997-03-28 1999-05-04 Ohmeda Inc. Inwardly directed wave mode ultrasonic transducer, gas analyzer, and method of use and manufacture
DE19510731C2 (en) * 1994-08-22 1999-09-16 Diehl Stiftung & Co Ultrasonic path in narrow channels of housings
EP1030176A2 (en) * 1999-02-15 2000-08-23 NGK Spark Plug Company Limited Gas concentration sensor
EP1336841A2 (en) * 2002-01-24 2003-08-20 Siemens-Elema AB Acoustic gas meter
EP1020723A3 (en) * 1999-01-11 2003-11-05 NGK Spark Plug Company Limited Gas concentration sensor
WO2003093812A3 (en) * 2002-05-01 2003-12-31 Air Prod & Chem Monitoring medical gas xenon concentration using ultrasonic gas analyser
JP2004223257A (en) * 2003-01-23 2004-08-12 Maquet Critical Care Ab Device for monitoring gas supply connection to mechanical respiration device, mechanical respiration device, and method for monitoring gas supply connection to inlet of mechanical respiration device
EP1464957A2 (en) * 2003-03-26 2004-10-06 Maquet Critical Care AB Acoustic analysis of gas mixtures
EP1477798A2 (en) 2003-04-28 2004-11-17 Maquet Critical Care AB Acoustic determination of moisture content of a gas mixture
FR2894487A1 (en) * 2005-12-14 2007-06-15 Air Liquide Xenon concentration determining device for ventilatory anesthesia apparatus, has infrared cell and paramagnetic oxygen cell to determine concentration of main gaseous components e.g. nitrogen, other than xenon of gaseous mixture
WO2008042734A2 (en) * 2006-09-29 2008-04-10 Praxair Technology, Inc. Heliox delivery system and method with positive pressure support
US8141552B2 (en) 2005-12-14 2012-03-27 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Respiratory anaesthesia apparatus with device for measuring the xenon concentration
WO2012130194A1 (en) * 2011-04-01 2012-10-04 Prochaska Ales Device for measuring oxygen concentration in gas mixtures containing helium and/or hydrogen
US20160082220A1 (en) * 2014-07-21 2016-03-24 Fisher & Paykel Healthcare Limited Fluid mixing structure
US11278215B2 (en) 2019-08-15 2022-03-22 Massachusetts Institute Of Technology Rhinometric sensing and gas detection

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US4280183A (en) * 1978-08-04 1981-07-21 S.S.O.S. Sub Sea Oil Services S.P.A. Gas analyzer
DE3009566A1 (en) * 1980-03-13 1981-09-17 Afriso Euro-Index GmbH für Sicherungsarmaturen und Füllstandmessung, 7129 Güglingen Carbon di:oxide determn. in gases - by measuring sound velocity
GB2086044A (en) * 1980-05-21 1982-05-06 Micro Pure Systems Inc Ultrasonic particulate identification
GB2087559A (en) * 1980-11-15 1982-05-26 Nat Maritime Inst Determining gas compositions acoustically
GB2195767A (en) * 1986-09-11 1988-04-13 Agricultural & Food Res Method and apparatus for on-line concentration measurement of a substance using ultrasonic pulses
GB2210977A (en) * 1987-10-14 1989-06-21 Gen Electric Co Plc Ultrasonic gas composition measurement
EP0352203A2 (en) * 1988-07-22 1990-01-24 Pluess Staufer Ag Method and apparatus for simultaneously measuring in a pipe the density, the concentration, the flowing rate, the delivery and the temperature of a liquid or a pasty fluid by ultrasonic transmission
AU6705890A (en) * 1989-11-30 1991-06-06 Puritan-Bennett Corporation Ultrasonic gas measuring device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4280183A (en) * 1978-08-04 1981-07-21 S.S.O.S. Sub Sea Oil Services S.P.A. Gas analyzer
DE3009566A1 (en) * 1980-03-13 1981-09-17 Afriso Euro-Index GmbH für Sicherungsarmaturen und Füllstandmessung, 7129 Güglingen Carbon di:oxide determn. in gases - by measuring sound velocity
GB2086044A (en) * 1980-05-21 1982-05-06 Micro Pure Systems Inc Ultrasonic particulate identification
GB2087559A (en) * 1980-11-15 1982-05-26 Nat Maritime Inst Determining gas compositions acoustically
GB2195767A (en) * 1986-09-11 1988-04-13 Agricultural & Food Res Method and apparatus for on-line concentration measurement of a substance using ultrasonic pulses
GB2210977A (en) * 1987-10-14 1989-06-21 Gen Electric Co Plc Ultrasonic gas composition measurement
EP0352203A2 (en) * 1988-07-22 1990-01-24 Pluess Staufer Ag Method and apparatus for simultaneously measuring in a pipe the density, the concentration, the flowing rate, the delivery and the temperature of a liquid or a pasty fluid by ultrasonic transmission
AU6705890A (en) * 1989-11-30 1991-06-06 Puritan-Bennett Corporation Ultrasonic gas measuring device

Cited By (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0657736A1 (en) * 1993-12-07 1995-06-14 Marwal Systems Apparatus for acoustically measuring the composition of a binary liquid
FR2713777A1 (en) * 1993-12-07 1995-06-16 Marwal Systems Device for measuring the composition of a liquid, in particular for measuring the level of additive in a motor vehicle fuel.
US5501098A (en) * 1993-12-30 1996-03-26 At&T Corp. Acoustic analysis of gas mixtures
US5392635A (en) * 1993-12-30 1995-02-28 At&T Corp. Acoustic analysis of gas mixtures
DE19510731C2 (en) * 1994-08-22 1999-09-16 Diehl Stiftung & Co Ultrasonic path in narrow channels of housings
US5816242A (en) * 1995-05-05 1998-10-06 Siemens Elema Ab Device for transmitting information via a patient tube in an intensive care or anesthetic machine
EP0740923A1 (en) * 1995-05-05 1996-11-06 Siemens-Elema AB Device for transmitting information via a patient tube in an intensive care or anesthetic machine
US5625140A (en) * 1995-12-12 1997-04-29 Lucent Technologies Inc. Acoustic analysis of gas mixtures
ES2114492A1 (en) * 1996-05-22 1998-05-16 Barba Trigueros Francisco Device for detecting in the air combustible gases supplied to non-industrial residential buildings by means of ultrasound.
US5792665A (en) * 1996-05-29 1998-08-11 Morrow, Iii; Donald W. Oxygen sensing method and hand held analyzer therefore
US5900552A (en) * 1997-03-28 1999-05-04 Ohmeda Inc. Inwardly directed wave mode ultrasonic transducer, gas analyzer, and method of use and manufacture
EP1020723A3 (en) * 1999-01-11 2003-11-05 NGK Spark Plug Company Limited Gas concentration sensor
EP1030176A3 (en) * 1999-02-15 2003-11-05 NGK Spark Plug Company Limited Gas concentration sensor
EP1030176A2 (en) * 1999-02-15 2000-08-23 NGK Spark Plug Company Limited Gas concentration sensor
EP1336841A2 (en) * 2002-01-24 2003-08-20 Siemens-Elema AB Acoustic gas meter
EP1336841A3 (en) * 2002-01-24 2005-09-14 Maquet Critical Care AB Acoustic gas meter
US6817250B2 (en) 2002-01-24 2004-11-16 Maquet Critical Care Ab Acoustic gas meter with a temperature probe having an elongated sensor region
WO2003093812A3 (en) * 2002-05-01 2003-12-31 Air Prod & Chem Monitoring medical gas xenon concentration using ultrasonic gas analyser
AU2003229968B2 (en) * 2002-05-01 2006-11-30 Air Products And Chemicals, Inc. Monitoring medical gas xenon concentration using ultrasonic gas analyser
JP2004223257A (en) * 2003-01-23 2004-08-12 Maquet Critical Care Ab Device for monitoring gas supply connection to mechanical respiration device, mechanical respiration device, and method for monitoring gas supply connection to inlet of mechanical respiration device
US7127936B2 (en) 2003-03-26 2006-10-31 Maquet Critical Care Ab Acoustic analysis of gas mixtures
EP1464957A2 (en) * 2003-03-26 2004-10-06 Maquet Critical Care AB Acoustic analysis of gas mixtures
EP1464957A3 (en) * 2003-03-26 2010-11-17 Maquet Critical Care AB Acoustic analysis of gas mixtures
EP1477798A3 (en) * 2003-04-28 2010-08-25 Maquet Critical Care AB Acoustic determination of moisture content of a gas mixture
EP1477798A2 (en) 2003-04-28 2004-11-17 Maquet Critical Care AB Acoustic determination of moisture content of a gas mixture
FR2894487A1 (en) * 2005-12-14 2007-06-15 Air Liquide Xenon concentration determining device for ventilatory anesthesia apparatus, has infrared cell and paramagnetic oxygen cell to determine concentration of main gaseous components e.g. nitrogen, other than xenon of gaseous mixture
US8141552B2 (en) 2005-12-14 2012-03-27 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Respiratory anaesthesia apparatus with device for measuring the xenon concentration
WO2008042734A3 (en) * 2006-09-29 2008-10-02 Praxair Technology Inc Heliox delivery system and method with positive pressure support
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