WO1980001836A1 - Calculateur de debit avec circuit d'adaptation a la courbe de vitesse - Google Patents

Calculateur de debit avec circuit d'adaptation a la courbe de vitesse Download PDF

Info

Publication number
WO1980001836A1
WO1980001836A1 PCT/US1980/000201 US8000201W WO8001836A1 WO 1980001836 A1 WO1980001836 A1 WO 1980001836A1 US 8000201 W US8000201 W US 8000201W WO 8001836 A1 WO8001836 A1 WO 8001836A1
Authority
WO
WIPO (PCT)
Prior art keywords
velocity
flow
relationship
pipe
values
Prior art date
Application number
PCT/US1980/000201
Other languages
English (en)
Inventor
T Campbell
F Lowell
Original Assignee
Ocean Res Equip Inc
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 Ocean Res Equip Inc filed Critical Ocean Res Equip Inc
Publication of WO1980001836A1 publication Critical patent/WO1980001836A1/fr

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

Definitions

  • Accoustic flow meters are becoming increasingly popular in measurement of fluid flow in pipes. Good accuracy can be achieved with essentially no pressure drop due to metering; thus, pumping energy is conserved.
  • flow meters can be mounted on the exteriors of pipes (albeit, with some loss in accuracy) and, thus, they are desirable for use in measuring flow of hazardous materials.
  • acoustic flow meters do not increase markedly in cost with the size of the pipe being monitored.
  • flow meters are those described in U.S. Patents 3,940,985; 3,564,912; 3,537,309; 3,697,936; 3,720,105; 3,881,352; 3,882,722; 3,886,794; 3,901,078; 2,914,998; 3,974,693; 4,024,760; 3,546,935; 3,564,912; and 3,918,304.
  • a circuit means is provided to fit a generalized velocity distribution function to the velocity measurements obtained from opposed pairs of flow transducers and known boundary conditions.
  • the precise type of velocity distribution function used can be varied depending on the precise liquid measuring problem that is encountered.
  • x is a position along an axis in a plane transverse to the axis of the pipe in which flow is to be measured;
  • v(x) is the average velocity in a plane perpendicular to both the transverse plane and the x axis and located at the position x;
  • f n (x) are various functions of x; and
  • a n are coefficients whose values depend on the velocity and its distribution along the x axis.
  • the values of a n are determined from a limited number of discrete velocity measurements and the resultant particularized velocity distribution function is then integrated over the cross-sections of the pipe to yield the volumetric flow rate.
  • FIG. 1 is a schematic diagram of a flow-measuring system embodying the invention
  • FIG. 2 illustrates typical transducer placement in a pipe
  • FIG. 3 is a schematic diagram of circuitry used to perform calculations resulting in the generation of a volumetric flow rate signal according to the invention.
  • FIG. 4 shows representations pulse timing for a pair of" acoustical transducers.
  • a flow-measuring system embodying the invention is arranged to measure the flow of a fluid through a pipe 10.
  • the system includes a plurality of pairs of electro-acoustical transducer, a pair T1-T2 being shown in FIG. 1.
  • the transducers are alternately connected to a transmitter 13 and a receiver 14, respectively, by means of switches 15 and 17.
  • a time measurement unit 16 measure s the timing of signal s transmitted by the transmitter 13 and received by the receiver 14 and the time measurements, in turn, are converted to flow measurements by a processing unit 24. Referring next to FIG.
  • transducer pairs there are four pairs of electro-acoustical transducers positioned at the walls of a pipe 10, the transducer pairs being identified as T1 and T2; T3 and T3; T5 and T6; and T7 and T8.
  • the transducers can be typical ultrasonic flow transducers known in the fluid-flow-measuring art.
  • the upstream transducers T1, T3, T5 and T7 are caused to emit acoustic pulses which are received and converted to electrical signals by the downstream transducers T2, T4, T6 and T8.
  • the process is then repeated with transducers T2, T4, T6 and T8 transmitting and transducers T1, T3, T5, and T7 receiving.
  • each velocity measurement provides an average velocity in a plane parallel to the pipe axis and passing through the two transducers. Specifically, these planes are perpendicular to the x axis in FIGURE 2.
  • volumetric flow rate Q is then ascertained from the following integration:
  • the foregoing processing procedure will also work with non-symmetrical velocity profiles; thus it can be readily adapted to non-circular pipes and even to open-channel flow measurements, or similarly, to pipelines which are not flowing full.
  • a measurement device is then provided to measure the elevation of the free surface of the liquid in the channel or pipe to provide the value y(x).
  • any type of transducer which is convenient and appropriate for a particular application can be used to detect the level.
  • Another example of flow measurement according to the invention is a simplified arrangement which takes into account several inherent characteristics of most flow situations in pipelines. Specifically, in the usual pipeline, having a symmetrical cross-section, the velocity distribution is both symmetrical and continuous. Also, one can assume a zero gradient in velocity at the center of the pipe and, as before, zero velocity at the pipe walls. Further assumptions that are justified in most pipeline flow situations include: 1. a finite velocity gradient at the pipe wall; and
  • FIGS. 1 and 4 illustrate how signals from a pair of acoustic transducers can be advantageously processed to achieve a time measurement.
  • the time-measuring arrangement is described with respect to a single one of the four pairs of transducers, i.e. with respect to transducers T1 and T2.
  • a signal from the time measurement unit 16 initiates an electrical signal from the transmitter 13.
  • a resulting acoustical signal transmitted from transducer T1 is received by T2 and the resulting electrical signal from transducer T2 arrives at the receiver 14.
  • the switches 15 and 17 are positioned so that receiver 14 is connected to transducer T2 and transmitter 13 is connected to transducer T1.
  • the time measurement unit 16 measures the acoustic propogation time between T1 and T2, and after the switches 15 and 17 are reversed, it measures the time between T2 and T1.
  • the acoustical tranmission times from transducer T1 to transducer T2 and from transducer T2 to transducer T1 will be different and a function of the average fluid velocity intersecting path between the transducers T1 and T2. These differences in time are due to the fact that, when the acoustic signal and fluid have velocity components in the same direction, these components will add to each other and, when the velocity components are in the opposite direction, they will subtract.
  • the two transit times are used to calculate a line velocity reading according to the well-known formula, where ⁇ t is the difference between u pstream and downstream transit times between T1 and T2, t is the average of these transit times and C is a constant which is a function of timing frequency, the path length and the angle between the acoustic path and the direction of flow.
  • the time measurement unit 16 emits a timing pulse PI to the transmitter 13 and essentially immediately the transmitter causes the transducer T1 to emit a corresponding acoustical pulse. Subsequently, the transducer T2 receives the acoustical pulse and applies a corresponding electrical signal to the receiver 14 essentially simultaneously with the receipt of the acoustical pulse. The unit 16 measures the elapsed time between the pulses P1 and P2.
  • the time measurement unit 16 emits a pulse P2' to the transmitter 13 causing an acoustical signal to be transmitted from the transducer T2 to the transducer T1 with the receiver 14 transmitting a corresponding electrical pulse (P1') back to the measurement unit 16.
  • the measurement 16 measures the elapsed time between the pulses P2' and P1' and the elapsed times are converted by the processing unit 24 to a velocity measurement in accordance with the formula 10.
  • a sequencer (not shown) operating under the control of the processing unit 24 then causes the transmitter 13 and receiver 14 to be connected to the transducer pair T3-T4 where the velocity measurement is repeated. It is then repeated again for the transducer pairs T5-T6 and T7-T8.
  • the time-measuring and velocity calculating steps are shown at 40 in FIG. 3, the boxes V 1 _V 4 indicating the stored results of the velocity measurements and the boxes v 0 and V 5 indicating the stored boundary value velocities.
  • the processing unit performs the matrix manipulation indicated at 50 in FIG. 3 to determine the values of the coefficients a n , resulting in the particularized velocity formula indicated at 60.
  • the processing unit performs the integration indicated at 70 to determine the volumetric flow rate in the pipe 10 (FIG. 1).
  • the details of the digital processor 24 of FIG. 1 have been omitted since the construction of a processor operating as described above is well known to those skilled in the art. Since the processor is dedicated to repetitive performance of the same computational routine it can be constructed with a number of commercially available logic units. Alternatively, it can take the form of a fixed-program micro processor. It will thus be seen that the objects set forth above have been efficiently attained.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Volume Flow (AREA)

Abstract

Nouvelle methode et appareil de mesure acoustique du debit du type comprenant une pluralite de paires de transducteurs montes sur les parois d'un tuyau (10) transportant le fluide a mesurer. Chaque paire est formee de transducteurs amont (T1, T3, T5, T7) et aval (T2, T4, T6, T8) opposes qui projettent et recoivent mutuellement une energie acoustique le long d'un chemin acoustique intermediaire. Des circuits (16, 24) sont prevus pour qu'une fonction e distribution generale de la vitesse soit materialisee par un systeme de traitement de signaux relativement simple utilisant un procede de suivi de la courbe.
PCT/US1980/000201 1979-02-28 1980-02-28 Calculateur de debit avec circuit d'adaptation a la courbe de vitesse WO1980001836A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US1609679A 1979-02-28 1979-02-28
US16096 1998-01-30

Publications (1)

Publication Number Publication Date
WO1980001836A1 true WO1980001836A1 (fr) 1980-09-04

Family

ID=21775366

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1980/000201 WO1980001836A1 (fr) 1979-02-28 1980-02-28 Calculateur de debit avec circuit d'adaptation a la courbe de vitesse

Country Status (1)

Country Link
WO (1) WO1980001836A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2467392A1 (fr) * 1979-10-09 1981-04-17 Panametrics Procede et appareil de mesure de la vitesse moyenne d'un fluide
US4646575A (en) * 1983-05-11 1987-03-03 British Gas Corporation Ultrasonic flowmeter

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3564912A (en) * 1968-10-28 1971-02-23 Westinghouse Electric Corp Fluid flow measurement system
US3940985A (en) * 1975-04-18 1976-03-02 Westinghouse Electric Corporation Fluid flow measurement system for pipes
US4024760A (en) * 1975-07-25 1977-05-24 Westinghouse Electric Corporation Fluid flow measurement apparatus
US4109523A (en) * 1977-10-21 1978-08-29 Westinghouse Electric Corp. Method of determining acoustic flow meter correction factor

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3564912A (en) * 1968-10-28 1971-02-23 Westinghouse Electric Corp Fluid flow measurement system
US3940985A (en) * 1975-04-18 1976-03-02 Westinghouse Electric Corporation Fluid flow measurement system for pipes
US4024760A (en) * 1975-07-25 1977-05-24 Westinghouse Electric Corporation Fluid flow measurement apparatus
US4109523A (en) * 1977-10-21 1978-08-29 Westinghouse Electric Corp. Method of determining acoustic flow meter correction factor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Modern Developments in Flow Measurement -1972- (Peter Peregrinus Ltd. London), S.G. Fisher, et al, "Ultrasonics As A Standard for Volumetric Flow Measurement", pages 139-159 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2467392A1 (fr) * 1979-10-09 1981-04-17 Panametrics Procede et appareil de mesure de la vitesse moyenne d'un fluide
US4646575A (en) * 1983-05-11 1987-03-03 British Gas Corporation Ultrasonic flowmeter

Similar Documents

Publication Publication Date Title
SU753367A3 (ru) Устройство дл измерени объемного расхода в цилиндрическом трубопроводе
US3940985A (en) Fluid flow measurement system for pipes
US4331025A (en) Methods of measuring fluid viscosity and flow rate
US4432243A (en) Flow calculator with velocity curve fitting circuit means
US3564912A (en) Fluid flow measurement system
CA2702666C (fr) Procede et systeme pour detecter une accumulation de depot a l'interieur d'un debitmetre a ultrasons
CN102288235B (zh) 一种双道混合型超声波流量计及测量方法
US4317178A (en) Multiple velocity traverse flow rate measuring technique
EP0125845A1 (fr) Débimètre à ultrasons
US20080059085A1 (en) Device for Determining and/or Monitoring the Volume Flow Rate and/or Mass Flow Rate of a Medium to be Measured
CN105157771A (zh) 一种时差式超声波流量测量方法及装置
WO1988008516A1 (fr) Debitmetre ultrasonore pour fluide
CN114088151B (zh) 外夹式多声道超声波流量检测装置及检测方法
RU2660011C1 (ru) Способ и устройство для ультразвукового измерения расхода накладным методом и схемное устройство для управления ультразвуковым измерением расхода накладным методом
EP0017475A1 (fr) Débitmètre acoustique comprenant une correction en fonction du nombre de Reynolds
CN104457871A (zh) 一种流量计及流体测量方法
US3788140A (en) Electroacoustical flow metering apparatus
Johari et al. Direct measurement of circulation using ultrasound
US3314289A (en) Swirl flow meter transducer system
WO1980001836A1 (fr) Calculateur de debit avec circuit d'adaptation a la courbe de vitesse
RU2396518C2 (ru) Способ и устройство акустического измерения расхода газа
CN212083156U (zh) 一种气液两相流的含量测量装置
JP3668119B2 (ja) 流量測定装置
US3204455A (en) Ultrasonic flowmeter
RU2471153C2 (ru) Способ и система измерения суммарного расхода текучей среды и ультразвуковой расходомер

Legal Events

Date Code Title Description
AK Designated states

Designated state(s): GB NL