WO1991015737A1 - Ultrasonic flowmeter for fluids - Google Patents

Ultrasonic flowmeter for fluids Download PDF

Info

Publication number
WO1991015737A1
WO1991015737A1 PCT/DE1991/000258 DE9100258W WO9115737A1 WO 1991015737 A1 WO1991015737 A1 WO 1991015737A1 DE 9100258 W DE9100258 W DE 9100258W WO 9115737 A1 WO9115737 A1 WO 9115737A1
Authority
WO
WIPO (PCT)
Prior art keywords
ultrasound
flow rate
ultrasonic
flow
phase
Prior art date
Application number
PCT/DE1991/000258
Other languages
German (de)
French (fr)
Inventor
Nicolas Grein
Original Assignee
Robert Bosch Gmbh
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 Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO1991015737A1 publication Critical patent/WO1991015737A1/en

Links

Classifications

    • 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
    • G01F1/66—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 measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
    • G01F1/667—Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
    • G01P5/24—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the direct influence of the streaming fluid on the properties of a detecting acoustical wave
    • G01P5/245—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the direct influence of the streaming fluid on the properties of a detecting acoustical wave by measuring transit time of acoustical waves
    • G01P5/248—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the direct influence of the streaming fluid on the properties of a detecting acoustical wave by measuring transit time of acoustical waves by measuring phase differences

Definitions

  • the invention relates to a device for ultrasonic flow measurement of flowing media, with an ultrasound transmission and reception device, the measuring section of which intersects the medium flow at an angle ⁇ , the measuring section having an ultrasonic transmitter and an ultrasonic receiver at both ends .
  • a disadvantage of this method is that it is economically hardly possible in series production to make the distances 11 and 12 the same size, since there are always mechanical tolerances . In this respect, the influence of inconsistent sound velocities and the associated measurement errors cannot be completely eliminated. Substantial errors also occur if the transducers (transmitter, receiver) of both measuring sections do not have identical properties, which is always the case in series production with regard to mechanical and electrical tolerances. In particular, there is then a different temperature behavior, so that measurement errors can be expected.
  • a flow measuring device which has two oscillators.
  • One oscillator works with a variable and the other oscillator with a fixed frequency.
  • the flow rate is dependent on determined the oscillation frequencies of the two oscillators.
  • a device of the type mentioned at the outset in which a measuring section crosses the medium flow at an angle and an ultrasound transmitting and an ultrasound receiving device are arranged at the ends of the measuring section. By switching the converters of these devices, they can be used as transmitters or receivers.
  • the advantage is that there is only one measuring path length, the path of which is constant. As a result of the changeover, a measurement takes place alternately in or against the direction of flow of the medium. Due to the switchover to be carried out, however, a continuous measurement cannot be carried out. The changeover always leads to settling processes which must be hidden when determining the measurement result.
  • the device according to the invention with the features mentioned in the main claim has the advantage that continuous measurement in both directions of the medium flow is possible using only a single measuring section. The influence of a possibly non-constant speed of sound is eliminated by the measurement taking place in both directions.
  • Two ultrasound transmitters are provided, which emit fixed frequencies that differ from one another. One ultrasonic transmitter is at one end and the other ultrasonic transmitter at the other end the measuring section. An ultrasound receiver is also arranged in the end region of each measuring section, so that the transmission signal of one ultrasound transmitter is received by both the one and the other ultrasound receiver. The same applies to the transmission signal from the other ultrasound transmitter. Since the two ultrasound receivers have different distances from the respective ultrasound transmitter, there are runtime differences with regard to the respective transmission signal. With respect to each of the two frequencies, a phase shift can be determined by the time difference. The flow rate or the flow rate of the medium can then be determined from the two phase rotations.
  • the ultrasound transmitters emit their respective frequencies at the same time. Continuous radiation of the transmission signals is preferably provided, as a result of which transient processes are avoided.
  • each ultrasound receiver is connected to a crossover that divides the received signals into the components assigned to the two frequencies.
  • the components assigned to the two frequencies are then available at the outputs of each crossover.
  • the crossovers are phase meters for determining the Downstream phase rotations.
  • the two phase meters each receive the components assigned to the two frequencies, one phase meter being supplied with the two components assigned to one frequency and the other phase meter receiving the two components assigned to the other frequency as input variables.
  • an evaluation circuit which determines the flow rate or flow rate of the medium from the values determined by the phase meters. Alternatively or additionally, it is also possible to determine the speed of sound in the medium.
  • the ultrasound receivers By designing the ultrasound receivers as broadband microphones, phase errors or phase drift are so small that there is only a negligible effect on the measurement result.
  • This shows a schematic representation of the device for measuring the ultrasound flow of a flowing medium.
  • the figure shows a tube 1, which for example forms the intake duct of an internal combustion engine.
  • pipe 1 flows the necessary for the combustion Air at the speed VL.
  • a measuring section 2 operating according to the ultrasound principle is provided, the measuring axis 3 of which crosses the longitudinal axis 4 of the tube 1 at an angle a.
  • An ultrasound transmission and reception device 8 is arranged within niches 5 and 6 which penetrate the wall of the tube 1, an ultrasound transmitter 9 and 10 and an ultrasound receiver 11 and 12 being located at each end of the measuring section 2.
  • the arrangement is designed such that the niche 5 of the ultrasonic transmitter 9 is located on the end face, which is then followed by the ultrasonic receiver 11 in the direction of the measuring axis 3, which is approximately aligned with the wall 7 of the tube 1.
  • the ultrasound receiver 12 is located approximately in alignment with the wall 7 of the tube 1 and the ultrasound transmitter 10 on the front side of the recess 6.
  • the ultrasound receivers 11 and 12 are via lines 13 and 14 with inputs of crossovers
  • Each crossover 15, 16 has two outputs.
  • the crossover 15 has the outputs 17 and 18; the crossover 16 has the outputs 19 and 20.
  • phase meter PM1 leads to inputs of a phase meter PM1.
  • the outputs 18 and 20 of the crossovers 15 and 16 are connected to the inputs of a phase meter PM2.
  • the output 21 of the phase meter PM1 and the output 22 of the phase meter PM2 lead to an evaluation circuit 23 which, at its output 24, measures a measurement of the flow rate VL. signal. Additionally or alternatively, it is also possible that the sound velocity C measured in the medium is available as a measured value at the output 24.
  • the device in FIG. 1 has the following mode of operation:
  • the two ultrasound transmitters 9 and 10 operate simultaneously and continuously, and in the process emit fixed frequencies f1 and f2 which differ from one another.
  • the transmission signals are preferably designed as sine signals.
  • the two ultrasound receivers 11 and 12 are at a distance 1 from one another.
  • both ultrasound receivers 11 and 12 receive the sound from both ultrasound transmitters 9 and 10.
  • the sound waves from the ultrasound transmitter 9 reach the ultrasound receiver 11 at this time
  • phase rotation ⁇ 1 and in phase meter PM2 phase rotation ⁇ 2 between the respective ultrasound receivers 11 and 12 are determined separately for both frequencies fl and f2.
  • the phase rotations ⁇ l, $ 2 result from the equations
  • ⁇ 2 modulo 2 ⁇ .
  • the ambiguity of the phase measurements was expressed by the modulo operator.
  • the flow rate VL and the speed of sound C of the medium can be determined in accordance with the above equations.
  • the arrangement according to the invention has the advantage that simultaneous measurements in both directions, that is to say in and against the direction of flow of the medium, are carried out with a single measuring section 2. In this way, measurement errors can be avoided. From loading Another particular advantage is the continuous measurement by CW operation (continuous sine). A high level of interference immunity is provided if high-pressure resonance transmitters (ultrasonic transmitters 9, 10) are used.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Fluid Mechanics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Measuring Volume Flow (AREA)

Abstract

The invention concerns a device for the measurement, using ultrasonics, of the flow rate of fluids, the device having an ultrasonic transmitter/receiver unit whose measurement path crosses the fluid stream at an angle α, an ultrasonic transmitter and an ultrasonic receiver being located at each end of the measurement path. To avoid measurement errors, the invention calls for the ultrasonic transmitters (9, 10) to emit different frequencies (f1, f2) and for the flow speed (VL) or flow amount to be determined from the values of the phase angle rotation (Ζ1, Ζ2) measured by each of the ultrasonic receivers (11, 12) and due to the difference in propagation time occurring for each frequency (f1, f2).

Description

Vorrichtung zur ültraschall-Durchflußmessung von strömenden MedienDevice for ultrasonic flow measurement of flowing media
Stand der TechnikState of the art
Die Erfindung betrifft eine Vorrichtung zur Ültra¬ schall-Durchflußmessung von strömenden Medien, mit einer Ultraschallsende- und -empfangseinrichtung, deren Meßstrecke den Mediumstrom unter einem Winkel a kreuzt, wobei die Meßstrecke an beiden Enden je¬ weils einen Ultraschallsender und einen Ultra¬ schallempfänger aufweist.The invention relates to a device for ultrasonic flow measurement of flowing media, with an ultrasound transmission and reception device, the measuring section of which intersects the medium flow at an angle α, the measuring section having an ultrasonic transmitter and an ultrasonic receiver at both ends .
In vielen Bereichen der Technik ist es erforder¬ lich, die Durchflußgeschwindigkeit bzw. die Durch- flußmenge eines Mediumstroms zu erfassen. Insbeson¬ dere ist dies in der Kraftfahrzeugtechnik zur Be¬ stimmung der einer Brennkraftmaschine zugeführten Luftmenge erforderlich. Grundsätzlich tritt bei derartigen Durchflußmes- sungen das Problem auf, daß die Schallgeschwindig¬ keit eine starke Abhängigkeit von der Temperatur aufweist. Um diese Abhängigkeit zu eliminieren, ist es nötig, Messungen sowohl in als auch gegen die Strömungsrichtung durchzuführen. Es ist bekannt, eine simultane Messung mit zwei räumlich getrennten Meßstrecken durchzuführen, wobei die eine Me߬ strecke in und die andere Meßstrecke entgegen der Strömungsrichtung arbeitet. An den Endbereichen je¬ der Meßstrecke ist jeweils ein Ultraschallsender und ein Ultraschallempfänger vorhanden. Zwischen dem jeweiligen Sender und zugehörigen Empfänger be¬ steht der Abstand 11 bzw. 12. Nachteilig an dieser Methode ist, daß es in einer Serienproduktion wirt^ schaftlich kaum möglich ist, die Abstände 11 und 12 gleichgroß auszubilden, da stets mechanische To¬ leranzen vorliegen. Insofern kann der Einfluß nicht konstanter Schallgeschwindigkeiten und damit ein¬ hergehender Meßfehler nicht vollständig eliminiert werden. Wesentliche Fehler entstehen außerdem, wenn die Wandler (Sender, Empfänger) beider Meßstrecke nicht identische Eigenschaften haben, was im Hin¬ blick auf mechanische und elektrische Toleranzen stets bei einer Serienfertigung gegeben ist. Insbe¬ sondere liegt dann auch ein unterschiedliches Tem¬ peraturverhalten vor, so daß mit Meßfehlern zu rechnen ist.In many areas of technology it is necessary to record the flow rate or the flow rate of a medium flow. In particular, this is necessary in automotive engineering to determine the amount of air supplied to an internal combustion engine. The basic problem with such flow measurements is that the speed of sound has a strong dependence on temperature. In order to eliminate this dependency, it is necessary to carry out measurements both in and against the flow direction. It is known to carry out a simultaneous measurement with two spatially separated measuring sections, one measuring section working in and the other measuring section working against the flow direction. An ultrasonic transmitter and an ultrasonic receiver are provided at the end regions of each measuring section. There is a distance 11 or 12 between the respective transmitter and associated receiver. A disadvantage of this method is that it is economically hardly possible in series production to make the distances 11 and 12 the same size, since there are always mechanical tolerances . In this respect, the influence of inconsistent sound velocities and the associated measurement errors cannot be completely eliminated. Substantial errors also occur if the transducers (transmitter, receiver) of both measuring sections do not have identical properties, which is always the case in series production with regard to mechanical and electrical tolerances. In particular, there is then a different temperature behavior, so that measurement errors can be expected.
Aus der DE-OS 32 30 399 ist eine Durchflußmeßein¬ richtung bekannt, die zwei Oszillatoren aufweist. Der eine Oszillator arbeitet mit einer variablen und der andere Oszillator mit einer festen Fre¬ quenz. Die Durchflußmenge wird in Abhängigkeit von den Schwingungsfrequenzen der beiden Oszillatoren bestimmt.From DE-OS 32 30 399 a flow measuring device is known which has two oscillators. One oscillator works with a variable and the other oscillator with a fixed frequency. The flow rate is dependent on determined the oscillation frequencies of the two oscillators.
Ferner ist eine Vorrichtung der eingangs genannten Art bekannt, bei der eine Meßstrecke unter einem Winkel den Mediumstrom kreuzt und an den Me߬ streckenenden eine Ultraschallsende- und eine Ul¬ traschallempfangseinrichtung angeordnet sind. Durch Umschaltung der Wandler dieser Einrichtungen lassen sich diese als Sender oder als Empfänger benutzen. Der Vorteil besteht darin, daß es insofern nur eine Meßstreckenlänge gibt, deren Strecke konstant ist. Durch die Umschaltung erfolgt abwechselnd eine Mes¬ sung in bzw. gegen die Strömungsrichtung des Me¬ diums. Durch die vorzunehmende Umschaltung ist je¬ doch eine kontinuierliche Messung nicht durchführ¬ bar. Die Umschaltung führt stets zu Einschwingvor¬ gängen, die bei der Ermittlung des Meßergebnis' auszublenden sind.Furthermore, a device of the type mentioned at the outset is known in which a measuring section crosses the medium flow at an angle and an ultrasound transmitting and an ultrasound receiving device are arranged at the ends of the measuring section. By switching the converters of these devices, they can be used as transmitters or receivers. The advantage is that there is only one measuring path length, the path of which is constant. As a result of the changeover, a measurement takes place alternately in or against the direction of flow of the medium. Due to the switchover to be carried out, however, a continuous measurement cannot be carried out. The changeover always leads to settling processes which must be hidden when determining the measurement result.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Vorrichtung mit den im Haupt¬ anspruch genannten Merkmalen hat demgegenüber den Vorteil, daß eine kontinuierliche Messung in beiden Richtungen des Mediumstroms unter Verwendung nur einer einzigen Meßstrecke ermöglicht. Der Einfluß einer möglicherweise, nicht konstanten Schallge¬ schwindigkeit wird durch die in beiden Richtungen erfolgende Messung eliminiert. Es sind zwei Ultra¬ schallsender vorgesehen, die sich voneinander un¬ terscheidende feste Frequenzen abstrahlen. Der eine Ultraschallsender befindet sich an dem einen und der andere Ultraschallsender an dem anderen Ende der Meßstrecke. Im Endbereich jeder Meßstrecke ist ferner jeweils ein Ultraschallempfänger angeordnet, so daß das Sendesignal des einen Ultraschallsenders sowohl von dem einen als auch von dem anderen Ul¬ traschallempfänger aufgenommen wird. Gleiches gilt für das Sendesignal des anderen Ultraschallsenders. Da die beiden Ultraschallempfänger unterschiedliche Abstände zu dem jeweiligen Ultraschallsender haben, ergeben sich Laufzeitunterschiede im Hinblick auf das jeweilige Sendesignal. In bezug auf jede der beiden Frequenzen ist durch den LaufZeitunterschied jeweils eine Phasendrehung ermittelbar. Aus den beiden Phasendrehungen läßt sich dann die Durch¬ flußgeschwindigkeit bzw. die Durchflußmenge des Me¬ diums ermitteln.In contrast, the device according to the invention with the features mentioned in the main claim has the advantage that continuous measurement in both directions of the medium flow is possible using only a single measuring section. The influence of a possibly non-constant speed of sound is eliminated by the measurement taking place in both directions. Two ultrasound transmitters are provided, which emit fixed frequencies that differ from one another. One ultrasonic transmitter is at one end and the other ultrasonic transmitter at the other end the measuring section. An ultrasound receiver is also arranged in the end region of each measuring section, so that the transmission signal of one ultrasound transmitter is received by both the one and the other ultrasound receiver. The same applies to the transmission signal from the other ultrasound transmitter. Since the two ultrasound receivers have different distances from the respective ultrasound transmitter, there are runtime differences with regard to the respective transmission signal. With respect to each of the two frequencies, a phase shift can be determined by the time difference. The flow rate or the flow rate of the medium can then be determined from the two phase rotations.
Insbesondere ist vorgesehen, daß die Ultraschall¬ sender gleichzeitig ihre jeweilige Frequenz ab¬ strahlen. Bevorzugt ist eine kontinuierliche Ab- strahlung der Sendesignale vorgesehen, wodurch Ein- schwingvorgänge vermieden sind.In particular, it is provided that the ultrasound transmitters emit their respective frequencies at the same time. Continuous radiation of the transmission signals is preferably provided, as a result of which transient processes are avoided.
Besonders gute Ergebnisse sind erzielbar, wenn als Sendesignale Sinus-Signale eingesetzt werden.Particularly good results can be achieved if sine signals are used as transmission signals.
Für die Ermittlung der Meßergebnisse ist es vor¬ teilhaft, wenn jeder Ultraschallempfänger mit einer die Empfangssignale in die den beiden Frequenzen zugeordneten Komponenten zerlegenden Frequenzweiche verbunden ist. Die den beiden Frequenzen zugeordne¬ ten Komponenten stehen dann an Ausgängen jeder Fre¬ quenzweiche zur Verfügung.For the determination of the measurement results, it is advantageous if each ultrasound receiver is connected to a crossover that divides the received signals into the components assigned to the two frequencies. The components assigned to the two frequencies are then available at the outputs of each crossover.
Nach einer Weiterbildung der Erfindung sind den Frequenzweichen Phasenmesser zur Bestimmung der Phasendrehungen nachgeschaltet. Die beiden Phasen- messer erhalten jeweils die den beiden Frequenzen zugeordneten Komponenten, wobei dem einen Phasen¬ messer die der einen Frequenz zugeordneten beiden Komponenten und dem anderen Phasenmesser die der anderen Frequenz zugeordneten beiden Komponenten als Eingangsgrößen zugeführt werden.According to a development of the invention, the crossovers are phase meters for determining the Downstream phase rotations. The two phase meters each receive the components assigned to the two frequencies, one phase meter being supplied with the two components assigned to one frequency and the other phase meter receiving the two components assigned to the other frequency as input variables.
Ferner ist eine Auswerteschaltung vorgesehen, die aus den von den Phasenmessern ermittelten Werten die Durchflußgeschwindigkeit bzw. Durchflußmenge des Mediums bestimmt. Alternativ oder zusätzlich ist es möglich, auch die Schallgeschwindigkeit im Medium zu ermitteln.Furthermore, an evaluation circuit is provided which determines the flow rate or flow rate of the medium from the values determined by the phase meters. Alternatively or additionally, it is also possible to determine the speed of sound in the medium.
Durch die Ausbildung der Ultraschallempfänger als breitbandige Mikrophone sind Phasenfehler bzw. ist eine Phasendrift derart klein, daß lediglich eine vernachlässigbare Auswirkung auf das Meßergebnis erfolgt.By designing the ultrasound receivers as broadband microphones, phase errors or phase drift are so small that there is only a negligible effect on the measurement result.
Zeichnungdrawing
Die Erfindung wird im folgenden anhand der Figur näher erläutert. Diese zeigt eine schematische Dar¬ stellung der Vorrichtung zur Ültraschall-Durchflu߬ messung eines strömenden Mediums.The invention is explained in more detail below with reference to the figure. This shows a schematic representation of the device for measuring the ultrasound flow of a flowing medium.
Beschreibung eines AusführungsbeispielsDescription of an embodiment
Die Figur zeigt ein Rohr 1, das beispielsweise den Ansaugkanal einer Brennkraftmaschine bildet. Im Rohr 1 strömt die für die Verbrennung erforderliche Luft mit der Geschwindigkeit VL. Ferner ist eine nach dem Ultraschallprinzip arbeitende Meßstrecke 2 vorgesehen, deren Meßachse 3 unter einem Winkel a die Längsachse 4 des Rohrs 1 kreuzt.The figure shows a tube 1, which for example forms the intake duct of an internal combustion engine. In pipe 1 flows the necessary for the combustion Air at the speed VL. Furthermore, a measuring section 2 operating according to the ultrasound principle is provided, the measuring axis 3 of which crosses the longitudinal axis 4 of the tube 1 at an angle a.
Innerhalb von Nischen 5 und 6, die die Wandung des Rohrs 1 durchsetzen, ist eine Ultraschallsende- und -empfangseinrichtung 8 angeordnet, wobei sich an jedem Ende der Meßstrecke 2 ein Ultraschallsender 9 bzw. 10 und ein Ultraschallempfänger 11 bzw. 12 be¬ findet. Die Anordnung ist derart ausgebildet, daß stirnseitig der Nische 5 der Ultraschallsender 9 liegt, dem dann -in Richtung der Meßachse 3- der Ultraschallempfänger 11 folgt, der etwa mit der Wandung 7 des Rohrs 1 fluchtet. Auf der anderen Seite der Meßstrecke 2 liegt -etwa fluchtend zur Wandung 7 des Rohrs 1- der Ultraschallempfänger 12 und an der Stirnseite der Nische 6 der Ultraschall¬ sender 10.An ultrasound transmission and reception device 8 is arranged within niches 5 and 6 which penetrate the wall of the tube 1, an ultrasound transmitter 9 and 10 and an ultrasound receiver 11 and 12 being located at each end of the measuring section 2. The arrangement is designed such that the niche 5 of the ultrasonic transmitter 9 is located on the end face, which is then followed by the ultrasonic receiver 11 in the direction of the measuring axis 3, which is approximately aligned with the wall 7 of the tube 1. On the other side of the measuring section 2, the ultrasound receiver 12 is located approximately in alignment with the wall 7 of the tube 1 and the ultrasound transmitter 10 on the front side of the recess 6.
Die Ultraschallempfänger 11 und 12 sind über Lei¬ tungen 13 und 14 mit Eingängen von FrequenzweichenThe ultrasound receivers 11 and 12 are via lines 13 and 14 with inputs of crossovers
15 bzw. 16 verbunden. Jede Frequenzweiche 15,16 weist zwei Ausgänge auf. Die Frequenzweiche 15 be¬ sitzt die Ausgänge 17 und 18; die Frequenzweiche 16 weist die Ausgänge 19 und 20 auf.15 or 16 connected. Each crossover 15, 16 has two outputs. The crossover 15 has the outputs 17 and 18; the crossover 16 has the outputs 19 and 20.
Die Ausgänge 17 und 19 der Frequenzweichen 15 undThe outputs 17 and 19 of the crossovers 15 and
16 führen zu Eingängen eines Phasenmessers PM1. Die Ausgänge 18 und 20 der Frequenzweichen 15 und 16 sind mit Eingängen eines Phasenmesser PM2 verbun¬ den. Der Ausgang 21 des Phasenmesser PM1 und der Ausgangs 22 des Phasenmesser PM2 führen zu einer Auswerteschaltung 23, die an ihrem Ausgang 24 ein die Durchflußgeschwindigkeit VL betreffendes Meß- signal abgibt. Zusätzlich oder alternativ ist es auch möglich, daß am Ausgang 24 die im Medium ge¬ messene Schallgeschwindigkeit C als Meßwert zur Verfügung steht.16 lead to inputs of a phase meter PM1. The outputs 18 and 20 of the crossovers 15 and 16 are connected to the inputs of a phase meter PM2. The output 21 of the phase meter PM1 and the output 22 of the phase meter PM2 lead to an evaluation circuit 23 which, at its output 24, measures a measurement of the flow rate VL. signal. Additionally or alternatively, it is also possible that the sound velocity C measured in the medium is available as a measured value at the output 24.
Die Vorrichtung der Figur 1 weist folgende Funk¬ tionsweise auf:The device in FIG. 1 has the following mode of operation:
Es wird davon ausgegangen, daß die beiden Ultra¬ schallsender 9 und 10 gleichzeitig und kontinuier¬ lich arbeiten und dabei sich voneinander unter¬ scheidende feste Frequenzen fl und f2 ausstrahlen. Die Sendesignale sind vorzugsweise als Sinus-Si¬ gnale ausgebildet. Die beiden Ultraschallempfänger 11 und 12 weisen den Abstand 1 voneinander auf.It is assumed that the two ultrasound transmitters 9 and 10 operate simultaneously and continuously, and in the process emit fixed frequencies f1 and f2 which differ from one another. The transmission signals are preferably designed as sine signals. The two ultrasound receivers 11 and 12 are at a distance 1 from one another.
Aufgrund der zuvor beschriebenen und aus der Figur ersichtlichen Anordnung empfangen beide Ultra¬ schallempfänger 11 und 12 den Schall beider Ultra¬ schallsender 9 und 10. Dabei erreichen die Schall¬ wellen des Ultraschallsenders 9 den Ultraschall¬ empfänger 11 um die ZeitBecause of the arrangement described above and apparent from the figure, both ultrasound receivers 11 and 12 receive the sound from both ultrasound transmitters 9 and 10. The sound waves from the ultrasound transmitter 9 reach the ultrasound receiver 11 at this time
tl =tl =
C + VL • cos αC + VL • cos α
früher als den Ultraschallempfänger 12. Ent¬ sprechend beträgt für den Schall des Ultraschall- senders 10 die Laufzeit zwischen den Ultraschall¬ empfängern 12 und 11earlier than the ultrasound receiver 12. Correspondingly, for the sound of the ultrasound transmitter 10, the transit time between the ultrasound receivers 12 and 11
t2 =t2 =
C - VL • cos α Die Empfangssignale der als breitbandige Mikrophone ausgebildete Ultraschallempfänger 11,12 werden über die Leitungen 13 und 14 den Frequenzweichen 15 und 16 zugeleitet, die diese Signale in die den Fre¬ quenzen fl und f2 zugeordnete Komponenten zerlegt. Im Phasenmesser PM1 wird insofern die Phasendrehung §1 und im Phasenmesser PM2 die Phasendrehung Φ2 zwischen den jeweiligen Ultraschallempfängern 11 und 12 getrennt für beide Frequenzen fl und f2 er¬ mittelt. Die Phasendrehungen Φl, $2 ergeben sich nach den GleichungenC - VL • cos α The received signals of the ultrasound receivers 11, 12 designed as broadband microphones are fed via lines 13 and 14 to the crossovers 15 and 16, which decomposes these signals into the components assigned to the frequencies fl and f2. In phase meter PM1, phase rotation §1 and in phase meter PM2, phase rotation Φ2 between the respective ultrasound receivers 11 and 12 are determined separately for both frequencies fl and f2. The phase rotations Φl, $ 2 result from the equations
2π - fl • 12π - fl • 1
Φl = modulo 2πΦl = modulo 2π
C + VL • cos αC + VL • cos α
2~ • f2 • 12 ~ • f2 • 1
Φ2 = modulo 2π .Φ2 = modulo 2π.
C - VL • cos αC - VL • cos α
Die Vieldeutigkeit der Phasenmessungen wurde hier¬ bei durch den modulo-Operator ausgedrückt.The ambiguity of the phase measurements was expressed by the modulo operator.
Mit Hilfe der Auswerteschaltung 23, die zum Bei¬ spiel eine EPROM-Tabelle oder einen Mikrorechner aufweisen kann, lassen sich gemäß der vorstehenden Gleichungen die Durchflußgeschwindigkeit VL sowie die Schallgeschwindigkeit C des Mediums, also der Luft, bestimmen.With the aid of the evaluation circuit 23, which may have an EPROM table or a microcomputer, for example, the flow rate VL and the speed of sound C of the medium, ie the air, can be determined in accordance with the above equations.
Die erfindungsgemäße Anordnung hat den Vorteil, daß gleichzeitige Messungen in beiden Richtungen, das heißt, in und entgegen der Strömungsrichtung des Mediums, mit einer einzigen Meßstrecke 2 erfolgt. Hierdurch lassen sich Meßfehler vermeiden. Von be- sonderem Vorteil ist auch die kontinuierliche Mes¬ sung durch CW-Betrieb (Dauersinus) . Eine hohe Stör- sicherheit ist gegeben, wenn schalldruckstarke Re¬ sonanzsender (Ultraschallsender 9,10) eingesetzt werden. The arrangement according to the invention has the advantage that simultaneous measurements in both directions, that is to say in and against the direction of flow of the medium, are carried out with a single measuring section 2. In this way, measurement errors can be avoided. From loading Another particular advantage is the continuous measurement by CW operation (continuous sine). A high level of interference immunity is provided if high-pressure resonance transmitters (ultrasonic transmitters 9, 10) are used.

Claims

- 1iAnsprüche - 1 claims
1. Vorrichtung zur Ültraschall-Durchflußmessung von strömenden Medien, mit einer Ultraschallsende- und -empfangseinrichtung, deren Meßstrecke den Medium¬ strom unter einem Winkel kreuzt, wobei die Me߬ strecke an beiden Enden jeweils einen Ultraschall¬ sender und einen Ultraschallempfänger aufweist, da¬ durch gekennzeichnet, daß die Ultraschallsender (9,10) sich voneinander unterscheidende Frequenzen (fl,f2) abstrahlen und daß aus den Werten der je¬ weils durch den LaufZeitunterschied für jede Fre¬ quenz auftretenden, von den Ultraschallempfangern (11,12) erfaßten Phasendrehung (Φ1,Φ2) die Durch¬ flußgeschwindigkeit (VL) bzw. die Durchflußmenge bestimmt wird. *«1. Device for ultrasonic flow measurement of flowing media, with an ultrasound transmission and reception device, the measuring section of which crosses the medium flow at an angle, the measuring section having an ultrasound transmitter and an ultrasound receiver at both ends, da¬ characterized in that the ultrasound transmitters (9, 10) emit frequencies (fl, f2) which differ from one another and that the phase rotation detected by the ultrasound receivers (11, 12) for each frequency due to the transit time difference (Φ1, Φ2) the flow rate (VL) or the flow rate is determined. * «
2. Vorrichtung nach Anspruch 1, dadurch gekenn¬ zeichnet, daß die Ultraschallsender (9,10) gleich¬ zeitig ihre jeweilige Frequenz (fl,f2) abstrahlen. 2. Device according to claim 1, characterized gekenn¬ characterized in that the ultrasonic transmitter (9,10) simultaneously emit their respective frequency (fl, f2).
3. Vorrichtung nach einem der vorhergehenden An¬ sprüche, dadurch gekennzeichnet, daß eine konti¬ nuierliche Abstrahlung der Sendesignale verfolgt.3. Device according to one of the preceding claims, characterized in that a continuous emission of the transmitted signals is tracked.
4. Vorrichtung nach einem der vorhergehenden An¬ sprüche, dadurch gekennzeichnet, daß jedes Sende¬ signal ein Sinus-Signal ist.4. Device according to one of the preceding claims, characterized in that each Sende¬ signal is a sine signal.
5. Vorrichtung nach einem der vorhergehenden An¬ sprüche, dadurch gekennzeichnet, daß jeder Ultra¬ schallempfänger (11,12) mit einer die Empfangs- signale in die den beiden Frequenzen (fl,f2) zuge¬ ordneten Komponenten zerlegenden Frequenzweiche (15) verbunden ist.5. Device according to one of the preceding claims, characterized in that each ultrasound receiver (11, 12) is connected to a crossover (15) separating the received signals into the components assigned to the two frequencies (fl, f2) is.
6. Vorrichtung nach einem der vorhergehenden An¬ sprüche, dadurch gekennzeichnet, daß den Fre¬ quenzweichen (15) Phasenmesser (PM1,PM2) zur Be¬ stimmung der Phasendrehungen (Φ1,Φ2) nachgeschaltet sind.6. Device according to one of the preceding claims, characterized in that the frequency crossovers (15) phase meters (PM1, PM2) for determining the phase rotations (Φ1, Φ2) are connected downstream.
7. Vorrichtung nach einem der vorhergehenden An¬ sprüche, gekennzeichnet durch eine Auswerteschal- tung (23) , die aus den ermittelten Werten die Durchflußgeschwindigkeit (VL) bzw. Durchflußmenge und/oder die Schallgeschwindigkeit (C) bestimmt.7. Device according to one of the preceding claims, characterized by an evaluation circuit (23) which determines the flow rate (VL) or flow rate and / or the speed of sound (C) from the determined values.
8. Vorrichtung nach einem der vorhergehenden An¬ sprüche, dadurch gekennzeichnet, daß die Ultra- schallempfänger (11,12) als breitbandige Mikrophone ausgebildet sind. 8. Device according to one of the preceding claims, characterized in that the ultrasound receivers (11, 12) are designed as broadband microphones.
PCT/DE1991/000258 1990-04-10 1991-03-23 Ultrasonic flowmeter for fluids WO1991015737A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19904011526 DE4011526A1 (en) 1990-04-10 1990-04-10 DEVICE FOR ULTRASONIC FLOW MEASUREMENT OF FLOWING MEDIA
DEP4011526.7 1990-04-10

Publications (1)

Publication Number Publication Date
WO1991015737A1 true WO1991015737A1 (en) 1991-10-17

Family

ID=6404111

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1991/000258 WO1991015737A1 (en) 1990-04-10 1991-03-23 Ultrasonic flowmeter for fluids

Country Status (2)

Country Link
DE (1) DE4011526A1 (en)
WO (1) WO1991015737A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2259571A (en) * 1991-09-16 1993-03-17 British Gas Plc Flowmeter eliminating transducer delay errors

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE515156C2 (en) 1998-03-25 2001-06-18 Thermo Measurement Ltd Method and apparatus for determining the flow rate of a medium flowing in a channel
DE10026568C2 (en) * 2000-05-30 2002-11-21 Siemens Ag Connector for an ultrasonic transducer housing
DE10106308C1 (en) * 2001-02-12 2002-07-11 Siemens Ag Acoustic signal propagation time measuring method uses intersection of tangent to maximum gradient point of first half wave with zero line as time reference point
EP1777502A3 (en) * 2005-10-24 2009-05-06 Hydrometer GmbH Control circuit with LC filtering for ultrasonic flowmeters
DE102005059062B4 (en) * 2005-12-08 2009-08-27 Continental Automotive Gmbh Apparatus for determining a mass flow
DE102022114985B3 (en) * 2022-06-14 2023-10-05 Krohne Ag Ultrasonic flow meter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2826912A (en) * 1948-12-27 1958-03-18 Kritz Jack Acoustic velocity measuring system
US2949773A (en) * 1955-01-20 1960-08-23 Raytheon Co Measurement of relative velocity between fluid and solid bodies
DE1096050B (en) * 1958-10-14 1960-12-29 Nat Res Dev Ultrasonic flow meter
GB1551220A (en) * 1975-11-20 1979-08-22 Standard Telephones Cables Ltd Ultrasonic flowmeter
GB2091876A (en) * 1981-01-23 1982-08-04 Standard Telephones Cables Ltd Measuring fluid flow

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2826912A (en) * 1948-12-27 1958-03-18 Kritz Jack Acoustic velocity measuring system
US2949773A (en) * 1955-01-20 1960-08-23 Raytheon Co Measurement of relative velocity between fluid and solid bodies
DE1096050B (en) * 1958-10-14 1960-12-29 Nat Res Dev Ultrasonic flow meter
GB1551220A (en) * 1975-11-20 1979-08-22 Standard Telephones Cables Ltd Ultrasonic flowmeter
GB2091876A (en) * 1981-01-23 1982-08-04 Standard Telephones Cables Ltd Measuring fluid flow

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2259571A (en) * 1991-09-16 1993-03-17 British Gas Plc Flowmeter eliminating transducer delay errors
US5461931A (en) * 1991-09-16 1995-10-31 British Gas Plc Measurement system
GB2259571B (en) * 1991-09-16 1996-01-17 British Gas Plc Measurement system

Also Published As

Publication number Publication date
DE4011526A1 (en) 1991-10-17

Similar Documents

Publication Publication Date Title
DE10036732C2 (en) Device for flow velocity measurement with ultrasound
EP2386835B1 (en) Ultrasound measurement of the flow speed of a fluid in a tubular conduit
WO1989001609A1 (en) Ultrasonic flow measurement installation
EP2291619A1 (en) Method and measurement system for determining and/or monitoring the flow of a measurement medium through a measuring tube
DE2107586A1 (en) Ultrasonic flow meter
DE3225690C2 (en)
DE2552072A1 (en) DEVICE FOR MEASURING THE MEDIUM FLOW IN AN AXIS-SYMMETRIC PIPE
DE10211552A1 (en) Method and device for measuring the flow rate and method and device for measuring the flow rate
DE3940065C2 (en)
DE4335394C2 (en) Ultrasonic flow meter
WO1991015737A1 (en) Ultrasonic flowmeter for fluids
DE102005004331A1 (en) Ultrasonic signal travel time determination procedure measures phase difference using quadrature demodulation for partial inversion with clock and phase shifted clock signal
DE102018003311B4 (en) Method and measuring device for determining measurement information
DE2828937C2 (en)
DE102017009462B4 (en) Measuring device for determining a fluid variable
EP0956512A1 (en) Radar distance meter
WO1989004463A1 (en) Process and device for detecting errors in measurements of mass flow of materials
DE19633558A1 (en) Ultrasonic method of flow measurement for fluids
WO2002039069A2 (en) Coupling element for an ultrasonic flowmeter
EP3521774A1 (en) Ultrasound flow meter and method for determining the flow speed
DE19843806A1 (en) Device to measure rate of flow of fluids in tubular conduit by analyzing temporal or phase position of sound signals affected by speed of flowing medium
DE3608384C2 (en)
DE2813754A1 (en) METHOD AND DEVICE FOR DETECTING THE FLOW OF A MATERIAL BY WAVE ENERGY RADIATION
DE4241225A1 (en) Flow measurement arrangement using ultrasonic signals - has auxiliary circuit contg. additional ultrasonic receiver for compensating error factors, and includes ac voltage generator
WO2005031369A2 (en) Ultrasound sensor and method for measuring flow rate

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): JP US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LU NL SE