DE4131720A1 - Measuring vol. flow of gaseous medium, esp. in breathing appts. - determining frequency of oscillation of optical fibre clamped at one end in flow channel - Google Patents

Measuring vol. flow of gaseous medium, esp. in breathing appts. - determining frequency of oscillation of optical fibre clamped at one end in flow channel

Info

Publication number
DE4131720A1
DE4131720A1 DE4131720A DE4131720A DE4131720A1 DE 4131720 A1 DE4131720 A1 DE 4131720A1 DE 4131720 A DE4131720 A DE 4131720A DE 4131720 A DE4131720 A DE 4131720A DE 4131720 A1 DE4131720 A1 DE 4131720A1
Authority
DE
Germany
Prior art keywords
flow
oscillation
optical fibre
esp
gaseous medium
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
DE4131720A
Other languages
German (de)
Inventor
Claus Dr Rer Nat Renschen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Technische Universitaet Dresden
Original Assignee
Technische Universitaet Dresden
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 Technische Universitaet Dresden filed Critical Technische Universitaet Dresden
Priority to DE4131720A priority Critical patent/DE4131720A1/en
Publication of DE4131720A1 publication Critical patent/DE4131720A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/08—Detecting, measuring or recording devices for evaluating the respiratory organs
    • A61B5/087—Measuring breath flow
    • A61B5/0876—Measuring breath flow using means deflected by the fluid stream, e.g. flaps
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
    • G01F1/28—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow by drag-force, e.g. vane type or impact flowmeter
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
    • G01F1/32—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters
    • G01F1/325—Means for detecting quantities used as proxy variables for swirl
    • G01F1/3259—Means for detecting quantities used as proxy variables for swirl for detecting fluid pressure oscillations
    • G01F1/3266—Means for detecting quantities used as proxy variables for swirl for detecting fluid pressure oscillations by sensing mechanical vibrations

Landscapes

  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Medical Informatics (AREA)
  • Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Biophysics (AREA)
  • Molecular Biology (AREA)
  • Pathology (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Pulmonology (AREA)
  • Physiology (AREA)
  • Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)

Abstract

A light conducting fibre is clamped at one end in a channel in which the gas is flowing. The fibre is used in conjunction with a light source and a light receiver. The frequency of oscillation of the fibre is measured in the range of its natural frequency. USE/ADVANTAGE - Exploits new technique of using existing type of optical fibre device to eliminate errors caused by patient movement.

Description

Die Erfindung betrifft ein Verfahren zur Messung des Volumenstroms von strömenden gasförmigen Medien mit einer im Strömungskanal einseitig eingespannten Lichtleitfaser, einer Lichtquelle und einem Lichtempfänger, vorzugsweise für Beatmungseinrichtungen in der Medizintechnik.The invention relates to a method for measuring the volume flow of flowing gaseous media with one side in the flow channel clamped optical fiber, a light source and a light receiver, preferably for ventilation devices in medical technology.

Verfahren zur Messung des Volumenstroms von strömenden gasförmigen Medien unter Verwendung von Vorrichtungen der eingangs genannten Art sind bereits bekannt. Gemessen wird die Auslenkung der Lichtleitfaser unter dem Druck des Volumenstroms, und zwar entweder direkt die Elongation des Austrittsquerschnitts der Lichtleitfaser mit einem positionsempfindlichen Lichtempfänger oder indirekt die Intensität des Lichteinfalls, die beispielsweise mit der Auslenkung zunimmt.Method for measuring the volume flow of flowing gaseous media using devices of the type mentioned are already known. The deflection of the optical fiber under pressure is measured of the volume flow, either directly elongating the Exit cross section of the optical fiber with a position sensitive Light receiver or indirectly the intensity of the incident light for example, increases with the deflection.

Für den speziellen Anwendungsfall in Beatmungseinrichtungen hat sich gezeigt, daß die geringen Volumenströme nur mit sehr empfindlichen Lichtleitfasern nachweisbar sind. Durch die geringe Federsteife überlagern sich den volumenstrombedingten Auslenkungen Faserschwingungen, die durch Bewegungen des Patienten verursacht werden. Ihre Frequenz liegt in der Größenordnung der Frequenz der zu messenden Elongationen. Sie verfälschen das Meßergebnis stark.For the special application in ventilation equipment shown that the low volume flows only with very sensitive Optical fibers are detectable. Overlay due to the low spring stiffness the volume flow-related deflections caused by fiber vibrations Movements of the patient are caused. Your frequency is in the Magnitude of the frequency of the elongations to be measured. They falsify the measurement result strong.

Aufgabe der Erfindung ist es, eine weitere Möglichkeit zur Messung des Volumenstroms mit einer der eingangs genannten Vorrichtungen anzugeben.The object of the invention is a further possibility for measuring the Volume flow with one of the devices mentioned above.

Es wurde gefunden, daß sich die Frequenz der durch die Strömung zum Schwingen angeregten Lichtleitfaser in Abhängigkeit vom Volumenstrom und von der Gasart signifikant ändert. Da im Regelfall mit bekannten Gasströmen gearbeitet wird, ist die Frequenz der schwingenden Lichtleitfaser bei entsprechender, die Gasart berücksichtigender Kalibrierung ein unmittelbares Maß für den Volumenstrom. Da es sich um eine höherfrequente Schwingung handelt, werden Fehler, wie sie aus Eigenschwingungen der Lichtleitfaser unter ihrem Eigengewicht bei Patientenbewegungen auftreten, in einfacher Weise eliminiert. It was found that the frequency of the flow to the Vibrate excited optical fiber depending on the volume flow and changes significantly from the gas type. As a rule with known gas flows is working, the frequency of the vibrating optical fiber is at corresponding calibration taking the type of gas into account direct measure of the volume flow. Since it is a higher frequency Vibrations are errors as they arise from the natural vibrations of Optical fiber occur under its own weight during patient movements, eliminated in a simple manner.  

Nachfolgend wird die Erfindung an Hand eines Ausführungsbeispiels näher dargestellt.The invention is explained in more detail below using an exemplary embodiment shown.

Bei einer für übliche Volumenstrommessungen konstruierten Vorrichtungen wurde das Ausgangssignal des Lichtempfängers über einen Hochpaß auf den Eingang eines elektronischen Frequenzmessers gelegt. Es ergaben sich folgende Meßwerte:For a device designed for conventional volume flow measurements was the output signal of the light receiver via a high pass to the Input of an electronic frequency meter placed. It turned out following measurements:

Sowohl bei impulsförmiger als auch bei konstanter Luftströmung lag die Irrtumswahrscheinlichkeit unter 1%.The was both with pulsed and constant air flow Error probability less than 1%.

Claims (1)

Verfahren zur Messung des Volumenstroms von strömenden gasförmigen Medien mit einer im Strömungskanal einseitig eingespannten Lichtleitfaser, einer Lichtquelle und einem Lichtempfanger, gekennzeichnet dadurch, daß die Schwingungsfrequenz der Lichtleitfaser im Bereich ihrer Eigenfrequenz gemessen wird.Method for measuring the volume flow of flowing gaseous media with an optical fiber clamped on one side in the flow channel, a light source and a light receiver, characterized in that the oscillation frequency of the optical fiber is measured in the region of its natural frequency.
DE4131720A 1991-09-24 1991-09-24 Measuring vol. flow of gaseous medium, esp. in breathing appts. - determining frequency of oscillation of optical fibre clamped at one end in flow channel Withdrawn DE4131720A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE4131720A DE4131720A1 (en) 1991-09-24 1991-09-24 Measuring vol. flow of gaseous medium, esp. in breathing appts. - determining frequency of oscillation of optical fibre clamped at one end in flow channel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE4131720A DE4131720A1 (en) 1991-09-24 1991-09-24 Measuring vol. flow of gaseous medium, esp. in breathing appts. - determining frequency of oscillation of optical fibre clamped at one end in flow channel

Publications (1)

Publication Number Publication Date
DE4131720A1 true DE4131720A1 (en) 1993-03-25

Family

ID=6441335

Family Applications (1)

Application Number Title Priority Date Filing Date
DE4131720A Withdrawn DE4131720A1 (en) 1991-09-24 1991-09-24 Measuring vol. flow of gaseous medium, esp. in breathing appts. - determining frequency of oscillation of optical fibre clamped at one end in flow channel

Country Status (1)

Country Link
DE (1) DE4131720A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10339907B4 (en) * 2003-08-29 2006-09-21 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Optical measuring apparatus and measuring methods for flows
DE102008037863A1 (en) * 2008-08-15 2010-04-15 Siemens Aktiengesellschaft Optical flow sensor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10339907B4 (en) * 2003-08-29 2006-09-21 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Optical measuring apparatus and measuring methods for flows
DE102008037863A1 (en) * 2008-08-15 2010-04-15 Siemens Aktiengesellschaft Optical flow sensor

Similar Documents

Publication Publication Date Title
AT505937B1 (en) METHOD FOR DETERMINING THE ACTUAL DENSITY OF FLUID MEDIA
EP3273209B1 (en) Method for operating a flow meter and flow meter
WO2004048898A1 (en) Method for determining the state of a field measuring instrument for process automation and process instrumentation, and field measuring instrument for carrying out the method
EP0345562B1 (en) Method and apparatus for processing measuring data
DE4131720A1 (en) Measuring vol. flow of gaseous medium, esp. in breathing appts. - determining frequency of oscillation of optical fibre clamped at one end in flow channel
DE4205453C2 (en) Device for measuring hydraulic flow rates and leaks on a test object
DE2833831A1 (en) OPTOACOUSTIC ANALYZER
DE1064255B (en) Acoustic gas analyzer
EP1038160B1 (en) Method and device for the self-compensating measurement of volume flow rate of gases
EP0371355B1 (en) Process for supervising the flow of gas in a gas analyser and for correcting the interfering effects of pressure and flow on the measure signal
DE2827428A1 (en) Liquid or gas detection esp. liq. level detection in reactor vessel - with capillary tubes from vessel leading to external pressure meters
DE102014111732A1 (en) Field device for automation technology
DD256367A1 (en) METHOD OF DENSITY DETERMINATION OF A FLUID USING A SWIVEL COUNTER TO INCREASE THE MEASUREMENT SECURITY BY REDUNDANCY IN VOLUME REVALUATION
DE1598831C3 (en) Turbidity meter with control device
DE102004010661A1 (en) Continuous measurement of particle concentration in gases comprises measuring fluctuations in concentration using two sensors arranged along its direction of flow whose signals are used to calculate cross-correlation function
DE741980C (en) Arrangement for pressure measurement
DE2949564C2 (en) Device for measuring the radiation power of power-modulated optical transmitters, in particular of lasers
DE745722C (en) Device for controlling the amount of gas flowing to a smoke gas detector
DE2912537C3 (en) Device for analyzing gases in a gas container
DD262090A1 (en) METHOD FOR SIMULTANEOUS MEASUREMENT OF TURBIDITY AND PARTICLE CONCENTRATION OF LIQUIDS
DE102006010363A1 (en) Gaseous or fluid medium`s temperature determining method for use in e.g. fluid thermometer, involves connecting oscillating body with frequency meter, and determining temperature of medium from determined frequency of body
DD218465A1 (en) METHOD FOR MONITORING OILISOLATED HIGH VOLTAGE DEVICES, IN PARTICULAR. OELTRANSFORMATOREN
WO2024160311A1 (en) Method and device for determining substance proportions of a fluid mixture of substances and medical device
DE832684C (en) Flow meter
DE102004055741B4 (en) Non-dispersive infrared gas analyzer according to the two-jet principle

Legal Events

Date Code Title Description
8139 Disposal/non-payment of the annual fee