DE19907362C2 - Method for mixing oxygen with air in a ventilator with a venturi nozzle - Google Patents

Method for mixing oxygen with air in a ventilator with a venturi nozzle

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Publication number
DE19907362C2
DE19907362C2 DE19907362A DE19907362A DE19907362C2 DE 19907362 C2 DE19907362 C2 DE 19907362C2 DE 19907362 A DE19907362 A DE 19907362A DE 19907362 A DE19907362 A DE 19907362A DE 19907362 C2 DE19907362 C2 DE 19907362C2
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Germany
Prior art keywords
flow
oxygen
venturi nozzle
gas
air
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Expired - Lifetime
Application number
DE19907362A
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German (de)
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DE19907362A1 (en
Inventor
Thomas Rossen
Joachim Schroeter
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Draegerwerk AG and Co KGaA
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Draeger Medical GmbH
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Publication date
Application filed by Draeger Medical GmbH filed Critical Draeger Medical GmbH
Priority to DE19907362A priority Critical patent/DE19907362C2/en
Priority to FR0001197A priority patent/FR2789913B1/en
Publication of DE19907362A1 publication Critical patent/DE19907362A1/en
Application granted granted Critical
Publication of DE19907362C2 publication Critical patent/DE19907362C2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • A61M16/12—Preparation of respiratory gases or vapours by mixing different gases
    • 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
    • A61M16/12—Preparation of respiratory gases or vapours by mixing different gases
    • A61M16/122—Preparation of respiratory gases or vapours by mixing different gases with dilution
    • A61M16/125—Diluting primary gas with ambient air
    • A61M16/127—Diluting primary gas with ambient air by Venturi effect, i.e. entrainment mixers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/10—Mixing gases with gases
    • B01F23/19—Mixing systems, i.e. flow charts or diagrams; Arrangements, e.g. comprising controlling means
    • B01F23/191—Mixing systems, i.e. flow charts or diagrams; Arrangements, e.g. comprising controlling means characterised by the construction of the controlling means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/312—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof
    • B01F25/3121—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof with additional mixing means other than injector mixers, e.g. screens, baffles or rotating elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/312—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof
    • B01F25/3124—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof characterised by the place of introduction of the main flow
    • B01F25/31242—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof characterised by the place of introduction of the main flow the main flow being injected in the central area of the venturi, creating an aspiration in the circumferential part of the conduit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/314—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced at the circumference of the conduit
    • B01F25/3142—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced at the circumference of the conduit the conduit having a plurality of openings in the axial direction or in the circumferential direction
    • B01F25/31421—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced at the circumference of the conduit the conduit having a plurality of openings in the axial direction or in the circumferential direction the conduit being porous
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/32—Injector mixers wherein the additional components are added in a by-pass of the main flow
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/432—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction with means for dividing the material flow into separate sub-flows and for repositioning and recombining these sub-flows; Cross-mixing, e.g. conducting the outer layer of the material nearer to the axis of the tube or vice-versa
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/432—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction with means for dividing the material flow into separate sub-flows and for repositioning and recombining these sub-flows; Cross-mixing, e.g. conducting the outer layer of the material nearer to the axis of the tube or vice-versa
    • B01F25/4321—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction with means for dividing the material flow into separate sub-flows and for repositioning and recombining these sub-flows; Cross-mixing, e.g. conducting the outer layer of the material nearer to the axis of the tube or vice-versa the subflows consisting of at least two flat layers which are recombined, e.g. using means having restriction or expansion zones
    • B01F25/43211—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction with means for dividing the material flow into separate sub-flows and for repositioning and recombining these sub-flows; Cross-mixing, e.g. conducting the outer layer of the material nearer to the axis of the tube or vice-versa the subflows consisting of at least two flat layers which are recombined, e.g. using means having restriction or expansion zones using a simple by-pass for separating and recombining the flow, e.g. by using branches of different length
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F33/00—Other mixers; Mixing plants; Combinations of mixers
    • B01F33/80—Mixing plants; Combinations of mixers
    • B01F33/82—Combinations of dissimilar mixers
    • B01F33/821—Combinations of dissimilar mixers with consecutive receptacles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B01F35/21—Measuring
    • B01F35/211—Measuring of the operational parameters
    • B01F35/2111—Flow rate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B01F35/22—Control or regulation
    • B01F35/221—Control or regulation of operational parameters, e.g. level of material in the mixer, temperature or pressure
    • B01F35/2211—Amount of delivered fluid during a period
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/80—Forming a predetermined ratio of the substances to be mixed
    • B01F35/83—Forming a predetermined ratio of the substances to be mixed by controlling the ratio of two or more flows, e.g. using flow sensing or flow controlling devices
    • B01F35/833—Flow control by valves, e.g. opening intermittently

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Emergency Medicine (AREA)
  • Pulmonology (AREA)
  • Engineering & Computer Science (AREA)
  • Anesthesiology (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Hematology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Dispersion Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Accessories For Mixers (AREA)

Description

Die Erfindung betrifft ein Verfahren mit den Merkmalen des Oberbegriffs des Patentanspruchs 1.The invention relates to a method with the features of the preamble of claim 1.

Aus der EP 0 691 137 A2 ist ein Verfahren der genannten Art bekannt.A method of the type mentioned is known from EP 0 691 137 A2.

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren der genannten Art derart zu verbessern, daß das Verhältnis der Gaskomponenten zueinander in einem großen Bereich verändert werden kann.The invention has for its object a method of the above Kind to improve such that the ratio of the gas components to each other can be changed in a wide range.

Die Lösung der Aufgabe erfolgt mit den Merkmalen des Patentanspruchs 1.The problem is solved with the features of claim 1.

Vorteilhafte Ausgestaltungen der Erfindung sind in den Unteransprüchen angegeben.Advantageous embodiments of the invention are in the subclaims specified.

Ein Ausführungsbeispiel der Erfindung ist in der Figur dargestellt und im folgenden näher erläutert.An embodiment of the invention is shown in the figure and in following explained in more detail.

Es zeigen:Show it:

Fig. 1 schematisch den Aufbau eines Gasmischers mit einer Venturi-Düse, Fig. 1 shows schematically the structure of a gas mixer with a Venturi nozzle,

Fig. 2 ein Kennlinienfeld für den Gasmischer nach der Fig. 1, Fig. 2 is a characteristic diagram for the gas mixer according to FIG. 1,

Fig. 3 die Venturi-Düse nach der Fig. 1 mit vorge­ schalteter Mischkammer. Fig. 3, the venturi nozzle according to FIG. 1 with pre-switched mixing chamber.

Fig. 1 zeigt schematisch den Aufbau eines Gasmischers 1 zum Mischen einer ersten Gaskomponente aus einer ersten Gasquelle 2 mit einer zweiten Gaskomponente aus einer zweiten Gasquelle 3. Die erste Gasquelle 2 bein­ haltet eine in der Fig. 1 nicht dargestellte, mit Sauerstoff gefüllte Gasflasche und als zweite Gasquelle dient Umgebungsluft. Die erste Gasquelle 2 ist über einen Druckminderer 4, der den Sauerstoff auf einen Druck von etwa 2 bar entspannt, und ein erstes Dosierventil 5 mit einem Treibgasanschluß 6 einer Venturi-Düse 7 verbünden. Abströmseitig eines Gasauslasses 8 der Venturi-Düse 7 befinden sich eine erste Flußmeßeinrichtung 9 und ein Ver­ braucher 10. Über einen Ansaugkanal 11 der Venturi-Düse 7 wird Luft aus der Umgebung durch den von der Venturi-Düse 7 erzeugten Unterdruck angesaugt. Im Ansaugkanal 11 befinden sich eine Mischkammer 13, ein Rückschlagventil 12 und eine zweite Flußmeßeinrichtung 21. Abströmseitig des Druckminderers 4 zweigt von einem Verteiler 16 eine erste Bypassleitung 14 mit einem zweiten Dosierventil 15 ab, die innerhalb der Mischkammer 13 in den Ansaugkanal 11 mündet. Über die erste Bypassleitung 14 kann mittels des zweiten Dosierventils 15 ein erster Teilstrom aus der ersten Gasquelle 2 der angesaugten Umgebungsluft zugemischt werden. Durch das Rückschlagventil 12 wird verhindert, daß Gas aus dem Ansaugkanal 11 in die Umgebung abströmt. Im vorliegenden Fall vermindert sich das Volumen der angesaugten Umgebungsluft um das Volumen des zudosierten Sauerstoffs. Fig. 1 shows schematically the structure of a gas mixer 1 for mixing a first gas component from a first gas source 2 with a second gas component from a second gas source 3. The first gas source 2 contains an oxygen-filled gas bottle, not shown in FIG. 1, and ambient air serves as the second gas source. The first gas source 2 is connected via a pressure reducer 4 , which relaxes the oxygen to a pressure of approximately 2 bar, and a first metering valve 5 is connected to a propellant gas connection 6 of a Venturi nozzle 7 . Downstream of a gas outlet 8 of the venturi 7 there are a first flow measuring device 9 and a consumer 10 . Air is sucked in from the environment through the negative pressure generated by the venturi nozzle 7 via an intake duct 11 of the venturi nozzle 7 . A mixing chamber 13 , a check valve 12 and a second flow measuring device 21 are located in the intake duct 11 . On the downstream side of the pressure reducer 4 , a first bypass line 14 branches off from a distributor 16 with a second metering valve 15 , which opens into the intake duct 11 within the mixing chamber 13 . Via the first bypass line 14 , a first partial flow from the first gas source 2 can be mixed with the sucked-in ambient air by means of the second metering valve 15 . The check valve 12 prevents gas from flowing out of the intake duct 11 into the environment. In the present case, the volume of the ambient air drawn in is reduced by the volume of the oxygen added.

Aus der ersten Gasquelle 2 wird am Verteiler 16 ein zweiter Teilstrom ent­ nommen, der über eine zweite Bypassleitung 17 und ein drittes Dosierventil 18 zum Gasauslaß 8 der Venturi-Düse umgelenkt wird. Hierdurch kann das am Gasauslaß 8 austretende Mischgas mit der ersten Gaskomponente angereichert werden, wodurch sich einerseits der dosierte Gesamtgasfluß als auch die Sauerstoffkonzentration verändern lassen.From the first gas source 2 , a second partial flow is taken from the distributor 16 , which is deflected via a second bypass line 17 and a third metering valve 18 to the gas outlet 8 of the venturi nozzle. As a result, the mixed gas emerging at the gas outlet 8 can be enriched with the first gas component, as a result of which the metered total gas flow and the oxygen concentration can be changed on the one hand.

Die Dosierventile 5, 15, 18 sind als elektrisch ansteuerbare Ventile ausgeführt und über Signalleitungen 19 mit einer zentralen Auswerte- und Steuereinheit 20 verbunden. Als Dosierventile 5, 15, 18 sind besonders gut elektrisch ansteuerbare Proportionalventile geeignet. An die Steuereinheit 20 sind ebenfalls die Flußmeßeinrichtungen 9, 21 angeschlossen. Die Flußmeßeinrichtungen 9, 21 dienen einerseits zur Messung des an den Verbraucher 10 abgegebenen Gesamtgasflusses V, der mit der ersten Flußmeßeinrichtung 9 bestimmt wird, und andererseits zur Lieferung von Meßgrößen, aus denen die Sauerstoffkonzentration berechnet werden kann.The metering valves 5 , 15 , 18 are designed as electrically controllable valves and are connected to a central evaluation and control unit 20 via signal lines 19 . Dosing valves 5 , 15 , 18 are particularly well suited proportional valves which can be controlled electrically. The flow measuring devices 9 , 21 are also connected to the control unit 20 . The flow measuring devices 9 , 21 serve on the one hand to measure the total gas flow V delivered to the consumer 10 , which is determined with the first flow measuring device 9 , and on the other hand to supply measured variables from which the oxygen concentration can be calculated.

Die am Verbraucher 10 vorliegende Sauerstoffkonzentration FiO2 resultiert aus dem Gesamtgasfluß V und aus dem über den Ansaugkanal 11 angesaugten Umgebungsluft-Gasfluß VL, der mit der zweiten Flußmeßein­ richtung 21 bestimmt wird. Die Sauerstoffkonzentration wird in der Steuereinheit 20 aus der formelmäßigen Beziehung
The oxygen concentration FiO 2 present at the consumer 10 results from the total gas flow V and from the ambient air-gas flow V L sucked in via the intake duct 11 , which is determined with the second direction of flow measurement device 21 . The oxygen concentration is determined in the control unit 20 from the formula

FiO2 = 1 - 0,79 × VL/V
FiO 2 = 1 - 0.79 × V L / V

errechnet.calculated.

Die Arbeitsweise des erfindungsgemäßen Gasmischers soll anhand des in der Fig. 2 veranschaulichten Diagramms erläutert werden.The mode of operation of the gas mixer according to the invention will be explained using the diagram illustrated in FIG. 2.

In der Fig. 2 ist die sich am Verbraucher 10 einstellende Sauerstoffkonzen­ tration (FiO2) in Abhängigkeit des dem Verbraucher 10 zugeführten Gesamt­ gasflusses V für verschiedene Öffnungsstellungen des ersten Dosierventils 5, des zweiten Dosierventils 15 und des dritten Dosierventils 18 veranschaulicht. Zunächst sei der Fall betrachtet, daß das erste Dosierventil 5 geöffnet ist und die Dosierventile 15, 18 geschlossen sind. In Abhängigkeit des Öffnungsgrades des ersten Dosierventils 5 verändert sich lediglich der Gesamtgasfluß V, während die Sauerstoffkonzentration nahezu unverändert bleibt.In FIG. 2, the established at the consumer 10 oxygen concentrator is concentration (F i O 2) in dependence of the load 10 applied to the total gas flow V of the first for different opening positions of the metering valve 5, the second metering valve 15 and the third metering valve 18 is illustrated. Let us first consider the case where the first metering valve 5 is open and the metering valves 15 , 18 are closed. Depending on the degree of opening of the first metering valve 5 , only the total gas flow V changes, while the oxygen concentration remains almost unchanged.

Aufgrund der überkritischen Strömungsverhältnisse innerhalb der Venturi-Düse 7 läßt sich allein mit dem ersten Dosierventil 5 nur ein maximaler Gasfluß V von etwa 40 Liter pro Minute realisieren. Über den Ansaugkanal 11 wird, entsprechend des mit dem ersten Dosierventil 5 eingestellten Sauerstoff- Gasflusses, ein entsprechendes Umgebungsluftvolumen angesaugt. Soll im Bereich I bis zu einem Gesamtgasfluß V von 40 Liter pro Minute eine Sauer­ stoffkonzentration oberhalb von 40 Vol.% eingestellt werden, so geschieht dieses durch Öffnen des zweiten Dosierventils 15, wodurch ein Teil des an­ gesaugten Umgebungsluftvolumens durch Sauerstoff ersetzt wird. Dieses führt zu einem Abfall des mit der zweiten Flußmeßeinrichtung 21 gemessenen Umgebungsluftvolumens und damit eines Anstiegs der Sauerstoffkonzentration. Gesamtgasflüsse V oberhalb von 40 Liter pro Minute können im Bereich II durch Öffnen des dritten Dosierventils 18 eingestellt werden. Mittels der Dosierventile 15, 18 lassen sich sowohl der Gesamtgasfluß als auch die sich in dem Gasgemisch einstellende Sauerstoffkonzentration verändern. Because of the supercritical flow conditions within the venturi nozzle 7 , only a maximum gas flow V of about 40 liters per minute can be achieved with the first metering valve 5 alone. A corresponding ambient air volume is sucked in via the intake duct 11 , in accordance with the oxygen gas flow set with the first metering valve 5 . If an oxygen concentration above 40 vol.% Is set in area I up to a total gas flow V of 40 liters per minute, this is done by opening the second metering valve 15 , whereby part of the volume of ambient air sucked in is replaced by oxygen. This leads to a drop in the volume of ambient air measured with the second flow measuring device 21 and thus an increase in the oxygen concentration. Total gas flows V above 40 liters per minute can be set in area II by opening the third metering valve 18 . By means of the metering valves 15 , 18 , both the total gas flow and the oxygen concentration established in the gas mixture can be changed.

Gasgemische mit veränderbarer Sauerstoffkonzentration sind bis zu einem Gesamtgasfluß V von etwa 80 Liter pro Minute einstellbar.Gas mixtures with variable oxygen concentration are up to a total gas flow V of about 80 liters per minute adjustable.

Fig. 3 zeigt schematisch den Aufbau der Venturi-Düse 7 mit vorgeschal­ teter Mischkammer 13. Die Mischkammer 13 befindet sich im Leitungszug des Ansaugkanals 11. Gleiche Komponenten sind mit gleichen Bezugsziffern der Fig. 1 bezeichnet. Die Mischkammer 13 ist durch einen porösen Zylinder 22 in einen Innenraum 23 und einen Außenraum 24 unterteilt. Der Innenraum 23 ist Teil des Ansaugkanals 11, wobei sich das Rückschlagventil 12 am unteren Ende des Innenraums 23 befindet. Der Außenraum 24 ist mit der ersten Bypassleitung 14 verbunden. Der in die Mischkammer 13 einströmende Sauerstoff verteilt sich zunächst im Außenraum 24 gleichmäßig über die Außenfläche des porösen Zylinders 22 und gelangt durch dessen, in der Fig. 3 nicht dargestellten, Poren in den Innenraum 23, wo er sich mit der über das Rückschlag­ ventil 12 einströmenden Umgebungsluft vermischt. Der poröse Zylinder 22 wirkt hierbei als Laminator für die Sauerstoffeinströmung in den Innen­ raum 23 und bewirkt dort eine besonders gute Durchmischung der Gas­ komponenten. Fig. 3 shows schematically the structure of the Venturi nozzle 7 with the mixing chamber 13 upstream. The mixing chamber 13 is located in the line of the intake duct 11 . The same components are designated with the same reference numerals in FIG. 1. The mixing chamber 13 is divided into an interior 23 and an exterior 24 by a porous cylinder 22 . The interior 23 is part of the intake duct 11 , the check valve 12 being located at the lower end of the interior 23 . The outer space 24 is connected to the first bypass line 14 . The flowing into the mixing chamber 13, oxygen initially distributed uniformly in the outer space 24 via the outer surface of the porous cylinder 22 and passes through the, in FIG. 3, not shown, pores in the inner space 23, where it joins the via the check valve 12 incoming ambient air mixed. The porous cylinder 22 acts as a laminator for the influx of oxygen into the interior 23 and causes a particularly good mixing of the gas components there.

Claims (4)

1. Verfahren zum Mischen von Sauerstoff mit Luft in einem Beatmungs­ gerät mit einer Venturi-Düse (7), welche einen mit einer Sauerstoff­ quelle (2) verbundenen Treibgasanschluss (6), einen Ansaugkanal (11) für Luft und einen zu einem Verbraucher (10) führenden Gasaus­ lass (8) aufweist, mit den Schritten,
  • - mittels einer von der Sauerstoffquelle (2) abzweigenden ersten Bypassleitung (14) und einem zweiten Dosierventil (15) einen veränderbaren ersten Sauerstoff-Teilstrom in den Ansaug­ kanal (11) einzudosieren,
  • - anströmseitig der Venturi-Düse (7) ein erstes Dosierventil (5) anzuordnen, um einen Gesamtgasfluss V abströmseitig der Venturi-Düse (7) zu verändern,
gekennzeichnet durch die Schritte,
  • - den Gesamtgasfluss V mit einer ersten Flussmesseinrichtung (9) abströmseitig des Gasauslasses (8) der Venturi-Düse (7) zu messen,
  • - für einen Gesamtgasfluss V oberhalb von 40 Liter/Minute mit einer von der Sauerstoffquelle (2) abzweigenden zweiten Bypass­ leitung (17) und einem dritten Dosierventil (18) einen zweiten Sauerstoff-Teilstrom am Gasauslass (8) der Venturi-Düse (7) einzuspeisen.
1. Method for mixing oxygen with air in a respirator with a Venturi nozzle ( 7 ), which has a propellant gas connection ( 6 ) connected to an oxygen source ( 2 ), an intake duct ( 11 ) for air and one to a consumer ( 10 ) leading gas outlet ( 8 ), with the steps,
  • - by means of a first bypass line ( 14 ) branching off from the oxygen source ( 2 ) and a second metering valve ( 15 ) to meter a changeable first partial flow of oxygen into the intake duct ( 11 ),
  • - arranging upstream of the venturi nozzle (7), a first metering valve (5), downstream to a total gas flow V (7) to alter the Venturi nozzle,
characterized by the steps
  • - to measure the total gas flow V with a first flow measuring device ( 9 ) downstream of the gas outlet ( 8 ) of the venturi nozzle ( 7 ),
  • - For a total gas flow V above 40 liters / minute with a second bypass line ( 17 ) branching off from the oxygen source ( 2 ) and a third metering valve ( 18 ), a second partial oxygen flow at the gas outlet ( 8 ) of the venturi nozzle ( 7 ) feed.
2. Verfahren nach Anspruch 1, gekennzeichnet durch die Schritte, mit einer zweiten Flussmesseinrichtung (21) am Ansaugkanal (11) den Gasfluss VL der angesaugten Luft zu messen und die an den Verbraucher (10) abgegebene Sauerstoffkonzentration FIO2 aus der formelmäßigen Beziehung
FIO2 = 1 - 0,79 × VL/V
zu berechnen.2. The method according to claim 1, characterized by the steps of using a second flow measuring device ( 21 ) on the intake duct ( 11 ) to measure the gas flow V L of the intake air and the oxygen concentration F IO2 delivered to the consumer ( 10 ) from the formula
F IO2 = 1 - 0.79 × V L / V
to calculate. 3. Verfahren nach Anspruch 1 oder 2, gekennzeichnet durch die Schritte, im Leitungszug des Ansaugkanals (11) eine mit der ersten Bypass­ leitung (14) verbundene Mischkammer (13) vorzusehen.3. The method according to claim 1 or 2, characterized by the steps of providing a mixing chamber ( 13 ) connected to the first bypass line ( 14 ) in the line of the intake duct ( 11 ). 4. Verfahren nach Anspruch 3, gekennzeichnet durch die Schritte, innerhalb der Mischkammer (13) einen porösen, gasdurchströmbaren Zylinder (22) anzuordnen und den aus der ersten Bypassleitung (14) kommenden Sauerstoffstrom über die Außenfläche des Zylinders (22) einströmen zu lassen und die Vermischung mit der angesaugten Luft in seinem Innen­ raum (23) vorzunehmen.4. The method according to claim 3, characterized by the steps of arranging a porous, gas-flowable cylinder ( 22 ) within the mixing chamber ( 13 ) and allowing the oxygen flow coming from the first bypass line ( 14 ) to flow in via the outer surface of the cylinder ( 22 ) and to mix with the intake air in its interior ( 23 ).
DE19907362A 1999-02-20 1999-02-20 Method for mixing oxygen with air in a ventilator with a venturi nozzle Expired - Lifetime DE19907362C2 (en)

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DE19907362A DE19907362C2 (en) 1999-02-20 1999-02-20 Method for mixing oxygen with air in a ventilator with a venturi nozzle
FR0001197A FR2789913B1 (en) 1999-02-20 2000-01-31 VENTURI DEVICE FOR MIXING AT LEAST TWO GASEOUS COMPONENTS

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FR2789913B1 (en) 2005-08-05
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