AU740625B2 - Ultrasonic measuring system and method of operation - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): OHIO UNIVERSITY Invention Title: ULTRASONIC MEASURING SYSTEM AND METHOD OF OPERATION The following statement is a full description of this invention, including the best method of performing it known to me/us: -2- ULTRASONIC MEASURING SYSTEM AND METHOD OF OPERATION CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S.

Provisional Application No. 60/009,288, filed December 28, 1995.

BACKGROUND OF THE INVENTION The present invention relates to multiflow pipelines wherein multiple fluid phases flow through a single pipeline and, in particular, to the determination of the flow rates and film heights of the different fluid phases flowing within a pipeline.

S•In a variety of industrial and experimental applications, it is necessary to monitor the flow of a 1. 5 collection of fluids in a pipeline. For example, in the :00"0 oil and gas industry, three distinct fluid phases, i.e., S"oil, water, and gas, exist in horizontal pipelines.

Multiphase flow metering, wherein the velocity of each fluid phase flowing within a pipeline is metered, presents the potential for valuable insight into the analysis of multiphase pipeline stress and multiphase pipeline system design. Many of the conventional multiphase flow metering systems do not provide an *.":accurate indication of the flow velocity of each fluid 25 phase flowing within a pipeline because of inherent limitations in their methodology. Further, other conventional systems are prohibitively difficult to install or incorporate intrusive metering arrangements requiring interruption or alteration of the multiphase flow. Finally, many conventional systems are merely compatible with a limited range of pipeline designs and, accordingly, have limited utility.

Accordingly, there is a need for a multiphase flow metering system and method incorporating a non- 3 intrusive, versatile, accurate, readily installable, and cost effective multiphase fluid metering design.

SUMMARY OF THE INVENTION This need is met by the present invention wherein a method and an apparatus for the determination of fluid film heights of each fluid flowing within a multiflow pipeline and the generation and detection of velocimetric ultrasonic pulses within a selected fluid within the pipeline. By a "multiflow pipeline" we mean a pipeline through which multiple fluid phases flow.

In accordance with the present invention, there is provided an ultrasonic measuring system comprising: 15 a plurality of upstream ultrasonic transducers coupled to a multiflow pipeline and positioned along a first cross sectional portion of a multiflow pipeline; a plurality of downstream ultrasonic transducers coupled to a multiflow pipeline and positioned along a 20 second cross sectional portion of said multiflow pipeline; and a transducer control system coupled to said plurality of upstream ultrasonic transducers and said plurality of downstream ultrasonic transducers, wherein said transducer control system is operative to determine a flow velocity of a single fluid selected from a plurality of fluids present within said multiflow pipeline by generating an ultrasonic pulse in a first cross section of said pipeline and detecting said ultrasonic pulse in another cross section of said pipeline.

The first and second cross sectional portions are preferably substantially perpendicular to a flow axis of the pipeline.

The transducer control system may comprise a programmable controller and a signal multiplexer, and the signal multiplexer preferably includes signal outputs coupled to respective ones of the plurality of upstream and \\melbjfiles\homeS\Monice\Keep\speci\p37963.doc 05/04/00 4 downstream ultrasonic transducers. The transducer control system is preferably operative to cause ultrasonic signals to be generated at any one or more of the plurality of upstream and downstream ultrasonic transducers and detected at any one or more of the plurality of upstream and downstream ultrasonic transducers.

The transducer control system of the present invention is preferably operative to determine a film height of a selected fluid within the multiflow pipeline or to determine film heights of each of a plurality of fluids present within the multiflow pipeline by generating and detecting at least one ultrasonic pulse in a single cross section of the pipeline. Ultrasonic signals may be .generated and detected at a lowermost portion of a single 15 cross section of the multiflow pipeline. First and second reflected ultrasonic signals may be detected at the lowermost portion.

The transducer control system may be operative to generate and detect ultrasonic pulses within a single fluid selected from a plurality of fluids present within the multiflow pipeline and to determine a flow velocity of a single fluid selected from a plurality of fluids present within the multiflow pipeline by generating and detecting ultrasonic pulses within the single fluid. Preferably, the ultrasonic pulse is generated in a first cross section of the pipeline and detected in another cross section of the pipeline.

In accordance with the present invention there is further provided a method of determining a flow velocity of a single fluid selected from a plurality of fluids present within a multiflow pipeline, said method comprising the steps of: generating an ultrasonic pulse at a selected one of a plurality of upstream ultrasonic transducers coupled to said multiflow pipeline along a first cross sectional portion of said multiflow pipeline; and detecting said ultrasonic pulse at a selected one of a \\melbfiles\homeS\MoniCque\Keep\speci\P3786 3 .doc 05/04/00 5 plurality of downstream ultrasonic transducers coupled to said multiflow pipeline along a second cross sectional portion of said multiflow pipeline, wherein said selected upstream ultrasonic transducer and said selected downstream ultrasonic transducer are positioned within said single fluid.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS Fig. 1 is a schematic illustration of an apparatus for measuring a flow velocity of a fluid in a multiflow pipeline according to the present invention; Fig. 2 is a schematic illustration of a process 15 for determining fluid film heights in a two phase flow; Fig. 3 is a schematic illustration of a process for determining fluid film heights in a three phase flow; Fig. 4 is a schematic illustration of a process of measuring the flow velocity of a selected fluid layer; 20 Fig. 5A is a plan view of a transducer mount according to the present invention; and Fig. 5B is a plan view, taken along line 5B-5B of Fig. 5A, of a transducer mount according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION Fig. 1 illustrates an ultrasonic measuring system according to the present invention. According to one embodiment of the present invention described herein, the ultrasonic measuring system 30 is utilized to determine a flow velocity of a selected fluid in a multiflow, pipeline by generating and detecting velocimetric ultrasonic pulses in the selected fluid. According to another embodiment of the present invention described herein, the ultrasonic measuring system 30 is utilized to determine film heights of fluids flowing within the pipeline 10. It \\melbtfiles\homeS\Monique\Keep\speci\P37863.doc 05/04/00 6 is contemplated by the present invention that a fluid may comprise a single phase material, a gas or a liquid, or a dual phase material, a liquid mist entrained in a gas flow.

The ultrasonic measuring system 30 includes a plurality of upstream ultrasonic transducers 1-8 and a plurality of downstream ultrasonic transducers 1'-8' \\melbfiles\homeS\Monique\Keep\speci \P37863.doc 05/04/00 7 coupled to the multiflow pipeline 10 so as to enable transmission of an ultrasonic signal through fluid within the pipeline 10. The upstream ultrasonic transducers 1-8 are positioned along a first cross sectional portion 10a of the pipeline 10 and the downstream ultrasonic transducers are positioned along a second cross sectional portion 10b of the pipeline 10. The first cross sectional portion 10a and the second cross sectional portion 10b are substantially perpendicular to the flow axis 11 of the pipeline 10. A detailed view of an appropriate transducer mount 40 is described herein with reference to Figs. 5A and A transducer control system 31 is coupled to the upstream and downstream ultrasonic transducers 1-8, and includes a programmable controller 32, preferably a personal computer including a digital microprocessing unit, and a signal multiplexer 34. The signal multiplexer 34 includes signal outputs 35 coupled to respective ones of the plurality of upstream and downstream ultrasonic transducers 1-8, The controller 32 and the multiplexer 34 communicate via a digital data bus 36.

The transducer control system 31 is programmed so as to be operative to cause ultrasonic signals to be generated at one or more upstream or downstream ultrasonic transducers 1-8, and detected at one or more upstream or downstream ultrasonic transducers 1-8, 1 The particular transducer or transducers selected for generation and detection depends upon the requirements of the particular diagnostic application to be employed with the ultrasonic measuring system 30 of the present invention. For example, where the transducer control system 31 is programmed to determine the film height of a selected fluid within the multiflow pipeline or the film heights of each of a plurality of fluids present within the multiflow pipeline, at least one ultrasonic pulse is generated and detected in a 8 single cross section of the pipeline 10, the first cross sectional portion 10a. Depending upon the diagnostic scheme established for determination of the film heights, the ultrasonic pulse may or may not be detected and generated at the same transducer. Specific diagnostic schemes for determining film heights of fluids within the pipeline 10 utilizing the ultrasonic measuring system 30 of the present invention are presented herein with reference to Figs. 2 and 3.

Where the transducer control system 31 is programmed to determine a flow velocity of a single fluid selected from a plurality of fluids present within the multiflow pipeline 10, the transducer control system 31 is operative to generate and detect ultrasonic pulses 15 within the single fluid. For example, according to the flow velocity determination scheme described below with reference to Fig. 4, the flow velocity of a single fluid selected from a plurality of fluids present within the multiflow pipeline 10 is determined by generating an ultrasonic pulse in the first cross sectional portion and detecting the ultrasonic pulse in the second cross sectional portion ft is contemplated by the present invention that any number of upstream and downstream ultrasonic transducers 1-8, may be employed in the arrangement illustrated in Fig. i. Specifically, if a :more versatile or precise ultrasonic measuring system is desired, more than eight upstream and downstream transducers 1-8, can be utilized. Conversely, if the level of versatility or precision represented by the number of transducers illustrated in Fig. 1 is beyond the needs of one practicing the present invention, a fewer number of transducers may be utilized.

Referring now to Figs. 2 and 3, where like elements are indicated with like reference numerals, a multiflow pipeline 10 and a diagnostic scheme for determining film heights of fluids flowing therein are illustrated. The -9pipeline 10 has a known inside diameter d and includes a first fluid medium 14 having a first fluid film height a, and a second fluid medium 16 having a second fluid film height b. A first fluid interface 12 defines the mutual boundary between the first medium 14 and the second medium 16. A lower or primary ultrasonic transducer 1 is coupled to a lowermost portion of a first cross section of the pipeline 10. The primary transducer 1 is capable of generating an ultrasonic pulse at the lowermost portion of the pipeline 10 and is also capable of detecting an ultrasonic pulse generated at the primary transducer 1 and reflected back to the primary transducer 1 or generated elsewhere and transmitted to the primary transducer 1. According to 15 the present invention, the pulse generated by the 0 primary transducer 1 is either a single ultrasonic pulse or a finite succession of ultrasonic pulses.

As a sound wave signal passes through a medium, its o 0. amplitude, pressure, decreases or is attenuated as follows: PX P 0 e-CX equation (1) where P, is the pressure of the sound wave at a distance x fronm the source, PO is the pressure of the sound wave 0.0 at the source, and a is the absorption coefficient of the medium. The absorption coefficient of the medium is related to its properties as follows: a 27rf 2 ./Cpc 3 equation (2) where f is the frequency of the sound wave, A is the viscosity of the medium, p is the density of the medium, and c is the velocity of sound in the medium.

An interface between two media may be characterized by a plurality of ultrasonic propagation factors including: a first reflection factor for an ultrasonic wave incident on the interface from a first side of the interface; (ii) a second reflection factor for an ultrasonic wave incident on the interface from a second side of the interface; (iii) a first transmission 10 factor for an ultrasonic wave incident on the interface from a first side of the interface; and (iv) a second transmission factor for an ultrasonic wave incident on the interface from a second side of the interface.

When an ultrasonic wave encounters an interface between two media at normal incidence, the wave energy is partially reflected and partially transmitted, as shown in Fig. 2. The ratio of the pressure of a reflected wave to an incident wave is defined as the reflection factor, R: R ((pIcI p 2 c 2 I

C

1 p 2 c 2 equation (3) The ratio of the pressure of a transmitted wave to an incident wave is defined as the transmission factor, T: T [2p 2 c 2 /(pc I 1 p 2 c 2 equation (4) 15 where p, is the density of the first medium, c, is the velocity of sound in the first medium, P 2 is the density of the second medium, and c 2 is the velocity of sound in the second medium.

An ultrasonic signal is generated at the primary transducer I and propagates through the pipeline 10 as illustrated in Fig. 2 according to the relationships defined in equations and Pi is the pressure of the sound wave generated at the lowermost portion of the pipeline 10. Pi' is the pressure of the sound wave after it passes through the first medium 14 and meets the first interface 12 between the first medium 14 and a second medium 16. Pt is the pressure of a sound wave transmitted through the first interface 12.

P, is the pressure of a sound wave reflected from the first interface 12. Pr' is the pressure of the reflected sound wave after it passes back through the first medium 14 and Pt' is the pressure of the transmitted sound wave after it passes through the second medium 16.

The film height a of the first medium 14 and the film height b of the second medium 16 may be determined by generating the ultrasonic signal at the primary transducer 1 and detecting the ultrasonic signal 11 reflected from the first interface 12. For the convenience of illustration, the quantity e ax corresponding to the attenuation of the sound wave by a medium, and as set forth in equation will be identified herein as P,: Pa equation (la) Accordingly, Pi' P (Pa) equation Pr' Pr(P); Pr equation (6) P, is a magnitude set in the primary transducer 1 and is a magnitude detected at the primary transducer 1. The difference between Pi and Pr' is equal to the sum of the pressure A, absorbed in the first medium 14 between Pi and Pi', the pressure A 2 transmitted through 15 the first interface 12, and the pressure A 3 absorbed in the first medium 14 between Pr and Pr': Pi Pr' Ai A 2 equation (7) Ai can be expressed as follows: A: A 1 P Pi'. equation (8) Equation can be combined with equation A P Pi(Pa) P Pa). equation (9) A can be expressed as follows:

A

3 Pr Pr'. equation Equation (10) can be combined with equation 25

A

3 Pr' equation (11)

A

2 can be expressed in terms of an interface transmission factor, T, see equation as follows:

A

2 P' equation (12) Equation (12) can be combined with equation

A

2 P equation (13) Equations and (13) can be substituted into equation P, Pr' Pr'/(PO) Pr' 0 P P, P (Pa) 0 PP, 2 Pi(P) 2 Pr, P2 (pipi(T)) Pr P'2 Pr'/Pi(l-T) 12- [Pr'/Pi(1-T)] 2 equation (14) Equation (14) can be combined with equation (la): P. 2 eax equation where x is the film thickness, or film height a, of the first medium 14, a is determined using equation or measured in a calibration system including a medium of interest with a known film height, is measured at the primary transducer 1, and T is determined using equation or measured in a calibration system including the mediums of interest. P. is proportional to the electrical volts applied to the primary transducer 1 and can be quantified by experimentally calibrating the transducer using a hydrophone within the pipeline 10 to account for pressure lost in the walls of the pipeline 15 10, as will be appreciated by those skilled in the art.

Alternatively, Pi can be quantified by experimentally calibrating the transducer using a hydrophone within a calibration system simulating the actual pipeline 10, as will be appreciated by those skilled in the art.

Accordingly, since x is the only unknown in equation by generating and detecting an ultrasonic oaol pulse at the primary transducer 1 and solving equation (15) tor x, the film height a of the first medium 14 may be calculated. The film height a of the first medium 14 25 will be equal to x and may be confirmed by comparison with a film height determination derived from measuring the transit time of a sound wave reflected from the first interface 12. Specifically, the time required for the ultrasonic wave to travel from the primary transducer 1, through the first medium 14, be reflected at the first interface 12, and return back through the first medium 14 to the primary transducer 1 is defined as a first transit time t': t' (2a/c 14 a (t'c 14 equation (16) where c 4 the velocity of sound in the first medium 14, is a quantity which can be measured experimentally or a 13known quantity which has been previously determined for the medium of interest.

The film height b of the second medium 16 is the difference between the film height a of the first medium 14 and the known inside diameter d of the pipeline b =d a. equation (17) Fig. 3, illustrates a pipeline 10 having a known inside diameter d and including a first fluid medium 14, having a first fluid film height a, a second fluid medium 16, having a second fluid film height b, and a third fluid medium 18, having a third fluid film height e. A first fluid interface 12 defines the mutual boundary between the first medium 14 and the second medium 16. A second fluid interface 13 defines the 15 mutual boundary between the second medium 16 and the sees third medium 18.

0040 The film height a of the first medium 14 of Fig. 3 is determined in the same manner as the film height a of **Fig. with the understanding that equation becomes: [Pri'/Pi(I-T)]* e X equation where x is the film thickness, or film height a, of the first medium 14, 1, the absorption coefficient of the '"first medium 14, is determined in a calibration system 25 including the first medium 14 with a known film height, the pressure of the sound wave after it passes back through the first medium 14, is measured at the primary transducer 1, and T,the transmission factor across the first interface when the wave is traveling from the first medium 14 to the second medium 16, is determined in a calibration system including the mediums of interest. Further, the film height a of the first medium 14 will be equal to x and may be confirmed by comparison with a film height determination derived from measuring the transit time of a sound wave reflected from the first interface 12 in the manner described above with reference to Fig. 2.

14 The film height b of the second medium 16 of Fig. 3 is determined from the measurement of P1 2 at the primary transducer 1. P 2 can be expressed as follows: Pt2 Pt 2 (18)

P,

2 can be expressed as follows: Pt2 Pr 2

(T

1 (19) where is the transmission factor across the first interface 12 when the wave is traveling from the second medium 16 to the first medium 14.

Equation (18) can be combined with equation (19): Pt2' Pr 2

(T

1 (PI) Pr2' can be expressed as follows: Pr2' Pr2(Pa 2 (21) Equation (20) can be combined with equation (21): Pt 2 Pr 2 (P2) (T 1 (P (22) Pr2 can be expressed as follows: Pr2 Pt, Pt,' (23) where R 2 and T 2 are the reflection and transmission factors for a wave traveling from the second medium 16 20 to the third medium 18.

Equation (22) can be combined with Equation (23): Pt2 Pt T2) (P 2 (T (Pal). (24) Pt' can be expressed as follows: P2' PtI (Pa 2 25 Equation (24) can be combined with Equation Pt2' Pt (Pa 2 2 1T 2 (P (26) Pj can be expressed as follows: Pi1 Pi' (TI) (27) where T, is the transmission factor across the first interface 12 when the wave is traveling from the first medium 14 to the second medium 16.

Equation (26) can be combined with Equation (27): Pt2' Pi' (P.

2 2

(-T

2

(T

1 (28)

P

i can be expressed as follows: Pi' Pi (29) Equation (28) can be combined with Equation (29): 15 Pt 2 Pi (P.

2 2 (T (P, 1 and rewritten as: Pa2 [P 2

(P

1 2

(T

2

(T

2 e- 2 x (31) where x is the film thickness, or film height b, of the second medium 16, r2, the absorption coefficient of the second medium 14, is determined in a calibration system including the first medium 16 with a known film height, Pj', is measured at the primary transducer 1, and T, and T2' are determined in calibration systems including the respective mediums of interest. Further, the film height b of the second medium 16 may be confirmed by comparison with a film height determination derived from measuring the transit times of respective sound waves reflected from the first interface 12 and the second interface 13. Specifically, the film height a of the first medium 14 may be confirmed by comparison with a film height determination derived from measuring the transit time of a sound wave reflected from the first interface 12 in the manner described above with reference to Fig. 2. The film height b of the second medium 16 may be confirmed by noting the film height a of the first medium 14 and the time required for the ultrasonic wave to travel from the primary transducer 1, through the first medium 14 and the second medium 16, be 25 reflected at the first interface 12 and the second **interface 13, and return back through the first medium 14 and the second medium 16 to the primary transducer 1.

The second transit time t" is thus defined as: t" t'+(2b/c 6 b [c26(t"'-t')/21quation (32) where c 16 the velocity of sound in the second medium 16, is a quantity which can be measured experimentally or a known quantity which has been previously determined for the medium of interest.

The film height e of the third medium 18 is determined according to the following equation: e d a b equation (33) 16 where d, the inside diameter of the pipeline I0, is a known value.

Referring now to Fig. 4, where like elements are indicated with like reference numerals, a diagnostic scheme for determining the flow velocity of a selected fluid layer 20, flowing in the direction indicated generally by arrows 22, is illustrated. First, the cross sectional boundaries of each flow portion are determined from either the inside pipe diameter d and the fluid film heights a and b or the inside pipe diameter d and the fluid film heights a, b, and e, depending upon the number of flow portions, i.e. fluid phases, within the pipeline 10. The inside pipe S* diameter d is a known value and the fluid film heights a, b, and e may either be known values or may be determined according to the fluid film height determination scheme described herein with reference to Figs. 2 and 3. The fluid film heights a, b, and e, are *used to determine the boundaries of the distinct flow 20 portions within the pipeline eeeo To determine the flow velocity of the selected fluid layer 20, velocimetric ultrasonic signals, repres6nted schematically by paths 24, are generated and detected within a selected one of the plurality of flow 25 portions. An ultrasonic measuring system 30 for generating velocimetric ultrasonic signals within a single selected fluid layer is described herein in detail with reference to Fig. 1.

Flow velocity can be determined using velocimetric pulses within the selected fluid layer in a variety of diagnostic schemes. For example, according to one diagnostic scheme, velocimetric pulses are utilized to determine fluid velocity by measuring the change in transit time for a sound wave to travel in opposite directions between two points in a moving fluid. Specifically, as is illustrated in Fig. 4, a first pair of transducers include a generating 17 transducer S1 and a detecting transducer R2 positioned within the selected fluid and a second pair of transducers include a generating transducer S2 and a detecting transducer RI. The transducers S1, S2, RI, R2 are positioned in the selected fluid layer 20 and are separated along the axis of flow by a known distance y.

Velocimetric pulses are generated simultaneously at the first and second generating transducers S1, S2 and subsequently detected at the first and second detecting transducers Ri, R2. The time interval t, for the signal to travel in the upstream direction, from S2 to R1, and the time interval t 2 for the signal to travel in the downstream direction, from S1 to R2, are noted. The difference At between t, and t 2 can be related to the moving fluid as follows: At (2Vty cos8)/c 2 equation (34) where V. is the fluid velocity, y is the distance between S"the upstream and downstream transducers, 8 is the angle of inclination, with respect to the fluid flow direction, of the paths defined between the generating and detecting transducers, and c is the velocity of sound in the medium of interest. Where V, is the only unknown, the equation is solved to determine the fluid velocity Vf.

It should be noted that, for illustrative purposes, the paths 24 represent only a portion of the actual ultrasonic signal generated at the transducers Si, S2.

The actual ultrasonic signal generated at the transducers Si, S2 is substantially in the form of an ultrasonic wave originating at a point source and diverging radially outward therefrom. It is contemplated by the present invention that the ultrasonic signals generated at the transducers SI, S2 may represent any one of a variety of signal distributions, orientations, magnitudes, velocities, frequencies, etc., so long as the signal selected is one 18 that will travel through the medium of interest and be detected at a corresponding transducer.

In the event the medium of interest comprises a dual phase material, a liquid mist entrained in a gas flow, it is noted that equation can be used to determine the apparent density of the medium. The respective quantities of each material forming the dual phase flow can be determined from the apparent density of the medium.

Referring now to Figs. 5A and 5B, a transducer mount 40 is illustrated. The mount 40 includes a substantially circular support portion 42 which defines a transducer receiving cavity 44 therein. The diameter of the support portion 42 is selected so as to form a 15 close fit with a transducer inserted into the cavity 44.

A plurality of saw cuts 46 are provided in the support portion 42 to enable the support portion to yield slightly and maintain a friction fit as a transducer is .'.inserted into the cavity 44.

S. 20 The transducer mount 40 also includes a pipe engaging portion 48 which, in turn, includes a contoured •portion 50. The transducer mount is welded or otherwise fastened to a pipeline (not shown) such that the contoured portion engages the outer surface of the 25 pipeline and follows the contour of the outer surface of the pipeline. For example, where the transducer mount is to be coupled to a pipeline of circular cross section, the radius of curvature of the contoured portion 50 is substantially equal to the radius of curvature of the outer surface of the pipeline.

In one embodiment of the present invention, the transducer mount 40 defines a 0.25" (0.64 cm) thick stainless steel body extending a maximum of approximately 1.25" (3.2 cm) from the contoured portion 50 to the opposite end of the mount 40. The saw cuts 46 are 0.5" (1.27 cm) deep. The cavity 44 defines a 1.75" 19 (4.44 cm) inside diameter and is approximately 0.75" (1.92 cm) deep.

Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. For example, it is.

contemplated by the present invention that the values and variables determined according to the present invention may be determined through an estimation, a calculation, a measurement, or otherwise. Further, it should be understood that, for the purpose of the present specification and claims, a value or variable which is indicated to be determined is a value or ooo• 15 variable which is estimated, a calculated, or measured.

Throughout this specification and the claims, the words *o "comprise", "comprises" and "comprising" are used in a nonexclusive sense.

*o

Claims (12)

1. An ultrasonic measuring system comprising: a plurality of upstream ultrasonic transducers coupled to a multiflow pipeline and positioned along a first cross sectional portion of a multiflow pipeline; a plurality of downstream ultrasonic transducers coupled to a multiflow pipeline and positioned along a second cross sectional portion of said multiflow pipeline; and a transducer control system coupled to said plurality of upstream ultrasonic transducers and said plurality of downstream ultrasonic transducers, wherein said transducer control system is operative to determine a 15 flow velocity of a single fluid selected from a plurality of fluids present within said multiflow pipeline by generating an ultrasonic pulse in a first cross section of said pipeline and detecting said ultrasonic pulse in another cross section of said pipeline.

2. :An ultrasonic measuring system as claimed in claim 1 wherein said first cross sectional portion is substantially perpendicular to a flow axis of said pipeline *and wherein said second cross sectional portion is substantially perpendicular to said flow axis of said pipeline.

3. An ultrasonic measuring system claimed in claim 1 wherein said transducer control system comprises a programmable controller and a signal multiplexer and wherein said signal multiplexer includes signal outputs coupled to respective ones of said plurality of upstream and downstream ultrasonic transducers. \\melb-files\home$\Monique\Keep\speci\P37863.doc 5/04/00 21

4. An ultrasonic measuring system as claimed in claim 1 wherein said transducer control -system is operative to cause ultrasonic signals to be generated at one of said plurality of upstream and downstream ultrasonic transducers and detected at another of said plurality of upstream and downstream ultrasonic transducers. An ultrasonic measuring system as claimed in claim 1 wherein said transducer control system is operative to cause ultrasonic signals to be generated at any one of said plurality of upstream and downstream ultrasonic transducers and detected at any one of said plurality of upstream and downstream ultrasonic transducers. S. 9*

6. An ultrasonic measuring system as claimed in claim 1 wherein said transducer control -system is operative to determine a film height of a selected fluid within said multiflow pipeline.

7. An ultrasonic measuring system as claimed in claim 1 wherein said transducer control system is further operative to determine film heights ofeach of a plurality of fluids present within said multiflow pipeline by generating and detecting at least one ultrasonic pulse in a single cross section of said pipeline.

8. An ultrasonic measuring system as claimed in claim 6 wherein said transducer control system is operative to determine said film height of said selected fluid by causing ultrasonic signals to be generated and detected at a lowermost portion of a single cross section of said multiflow pipeline.

9. An ultrasonic measuring system as claimed in claim 8 wherein first and second reflected ultrasonic signals are detected at said lowermost portion. \\melb-files\homeS\Monique\Keep\speci\P37863.doc 5/04/00 22 An ultrasonic measuring system as claimed in claim 1 wherein said transducer control system is operative to generate and detect ultrasonic pulses within a single fluid selected from a plurality of fluids present within said multiflow pipeline.

11. An ultrasonic measuring system as claimed in claim 1 wherein said transducer control system is operative to determine flow velocity of a single fluid selected from a plurality of fluids present within said multiflow pipeline by generating and detecting ultrasonic pulses within said single fluid.

12. A method of determining a flow velocity of a single fluid selected from a plurality of fluids present within a multiflow pipeline, said method comprising the **steps of: generating an ultrasonic pulse at a selected one S 20 of a plurality of upstream ultrasonic transducers coupled to said multiflow pipeline along a first cross sectional portion of said multiflow pipeline; and detecting said ultrasonic pulse at a selected one of a plurality of downstream ultrasonic transducers coupled to said multiflow pipeline along a second cross sectional portion of said multiflow pipeline, wherein said selected upstream ultrasonic transducer and said selected downstream ultrasonic transducer are positioned within said single fluid.

13. An ultrasonic measuring system substantially as herein described with reference to and as illustrated by the accompanying drawings. \\melbfiles\homeS\Moniue\Keep\speci \P37863.doc 5/04/00 23

14. A method of determining a flow velocity of a single fluid selected from a plurality of fluids present within a multiflow pipeline substantially as herein described with reference to and as illustrated by the accompanying drawings. Dated this 5th day of April 2000 OHIO UNIVERSITY By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia C e C• C.. C O* \\melbfiles\homeS\Monique\Keep\speci\P37863.doc 5/04/00