Hybrid sensing ultrasonic flowmeter

A hybrid ultrasonic flowmeter includes at least a first sensing plane including four ultrasonic transducers (transducers) positioned in a parallelogram arrangement on a meter pipe wall including a first and second transducer pair. A first reflector is positioned between the first transducer pair on a first portion of the meter pipe wall, and a second ultrasonic reflector is between the second transducer pair on a second portion of the meter pipe wall opposite the first wall portion. The transducers have assembly angles and emission patterns for emitting ultrasonic beams to provide a plurality of direct measurement paths and a plurality of reflective paths involving a first reflective path involving the first ultrasonic reflector and a second reflective path involving the second ultrasonic reflector. A flow electronics module including a transceiver causes the transducers to transmit ultrasonic signals and processes sensing signals generated by the transducers for determining a volume flow.

FIELD

Disclosed embodiments relate to multi-path ultrasonic flowmeters.

BACKGROUND

Ultrasonic flowmeters are commonly used to determine the flow rate for a variety of fluids (e.g., liquids, gases) as well as the speed of sound in the fluid flowing in pipes having a variety of different sizes (e.g., 4-inch to 24-inch) and shapes. Knowledge of the flow rate of the fluid can enable other physical properties or qualities of the fluid to be determined. For example, in some custody-transfer applications, the flow rate can be used to determine the volume (Q) of a fluid (e.g., oil or gas) being transferred from a seller to a buyer through a pipe to determine the cost for the transaction, where the volume is equal to the flow rate multiplied by the cross-sectional area (A) of the pipe. In other applications, the speed of sound can be used to determine the mean molecular weight of a fluid flowing in a pipe to improve and/or control a chemical process or a combustion processes.

One type of ultrasonic flowmeter employs transit time flow metering, where one or more pairs of ultrasonic transducers are attached to a pipe (or a spool piece attached to a pipeline), where each transducer pair includes a transducer located upstream and a transducer located downstream from each other. Each transducer, when energized, transmits an ultrasonic beam or signal (e.g., a sound wave) along an ultrasonic path through the flowing fluid that is received by and is detected by the other transducer of the pair. The path velocity (i.e., path or chord velocity (Vp)) of the fluid averaged along an ultrasonic path can be determined as a function of the transit time differential between the transit time of an ultrasonic signal traveling along the ultrasonic path from the downstream transducer upstream to the upstream transducer against the fluid flow direction, and the transit time of an ultrasonic signal traveling along the ultrasonic path from the upstream transducer downstream to the downstream transducer along the fluid flow direction.

There are two different measurement principles used in known transit time ultrasonic flowmeters. A first type of ultrasonic flowmeter is a direct-path type that implements direct measuring using crossed paths between transducer (sensor) pairs, where there are no reflectors used. The ultrasonic transmitter and receiver for the direct-path type ultrasonic flowmeter are always located diagonally on opposite sides of the meter pipe wall. A second type of ultrasonic flowmeter is a reflective path type that implements indirect measuring paths using an ultrasonic reflector on the meter pipe wall opposite to the transducer pair to reflect the ultrasonic measurement signal received from the ultrasonic transmitter to the ultrasonic receiver, where the transducer pair is located at the same side of the meter pipe wall.

SUMMARY

Disclosed embodiments include hybrid ultrasonic flowmeters (hybrid flowmeters) which combine direct-path sensing and reflective (indirect) sensing in a single flowmeter realized by adding suitably placed reflector(s) to a direct-path ultrasonic flowmeter arrangement. In the direct-path, a portion of the transmitted signal is reflected by the opposite wall that can be detected at a second receiver next to the transmitter, forming a virtual reflective path. Reflectors placed on the meter pipe wall can be included to increase the efficiency of the reflective paths. Disclosed hybrid flowmeters realize an additional reflective path meter in a direct-path arrangement without the need to add any ultrasonic transducers.

Disclosed hybrid flowmeters comprise at least a first sensing plane including four ultrasonic transducers (transducers) positioned in a parallelogram arrangement on a meter pipe wall including a first and second transducer pair. A parallelogram is a 4-sided shape where opposite sides are parallel to one another. A rectangle is known in Euclidean plane geometry to be a special case of a parallelogram having adjacent sides which make right angles (90 degrees) to one another.

A first reflector is positioned between the first transducer pair on a first portion of the meter pipe wall, and a second ultrasonic reflector is between the second transducer pair on a second portion of the meter pipe wall opposite the first wall portion. The transducers have assembly angles and emission patterns (e.g., sufficiently wide emission angles) for providing a plurality of direct measurement paths including first and second direct measurement paths, and a plurality of reflective measurement paths including a first reflective path involving the first transducer pair and first ultrasonic reflector and a second reflective path involving the second transducer pair and second ultrasonic reflector. A flow electronics module including a transceiver, processor and a flow measurement algorithm causes the transducers to transmit ultrasonic signals and processes received sensing signals generated for determining a volume flow.

DETAILED DESCRIPTION

Disclosed embodiments are described with reference to the attached figures, wherein like reference numerals are used throughout the figures to designate similar or equivalent elements. The figures are not drawn to scale and they are provided merely to illustrate certain disclosed aspects. Several disclosed aspects are described below with reference to example applications for illustration. It should be understood that numerous specific details, relationships, and methods are set forth to provide a full understanding of the disclosed embodiments.

One having ordinary skill in the relevant art, however, will readily recognize that the subject matter disclosed herein can be practiced without one or more of the specific details or with other methods. In other instances, well-known structures or operations are not shown in detail to avoid obscuring certain aspects. This Disclosure is not limited by the illustrated ordering of acts or events, as some acts may occur in different orders and/or concurrently with other acts or events. Furthermore, not all illustrated acts or events are required to implement a methodology in accordance with the embodiments disclosed herein.

FIG. 1depicts an example hybrid flowmeter100shown installed between pipeline sections130aand130b(shown inFIG. 1as “pipe wall”) having a single sensing plane shown as a “plane” including four transducers101,102,103and104which are positioned in a parallelogram arrangement along the plane on the meter pipe wall105a, along with first ultrasonic reflector111and second ultrasonic reflector112, according to an example embodiment. Although the parallelogram arrangement shown inFIG. 1and generally throughout this Disclosure is a rectangular arrangement, disclosed hybrid flowmeters are in no way limited to rectangular transducer arrangements, and can utilize different path angles to form a parallelogram.

Hybrid flowmeter100includes a meter body105including a meter pipe wall105a. Connection flanges108are shown on each end of the hybrid flowmeter200for bolting the hybrid flowmeter100to the pipeline sections130aand130b.

Transducers101and103together provide a first transducer pair on a first portion1051of the meter pipe wall105ahaving a first ultrasonic reflector111positioned between, and transducers102and104together provide a second transducer pair on a second portion1052of the meter pipe wall105aopposite the first portion1051having a second ultrasonic reflector112positioned between. The first and second ultrasonic reflectors111and112are generally positioned on the inner side of the meter pipe wall105aand function to increase the efficiency (ultrasonic signal intensity) of the reflective path for the respective transducer pairs. Disclosed reflectors are generally in the conventional form of metal plates.

The transducers101,102,103and104each have assembly angles and emission patterns (e.g., suitably wide emission angle) for providing the first direct measurement path136and the second direct measurement path137shown together forming an X pattern, and 2 reflective paths including a first single reflective path131in a V-pattern involving the first ultrasonic sensing pair comprising transducers101and103and the second reflector112and a second single reflective path132in a V-pattern involving the second transducer pair comprising transducers102and104and the first reflector111. As noted above, this arrangement realizes additional reflective path flow sensing from a direct-path arrangement by adding reflectors without the need to add any transducers.

The flow electronics module120is shown including a processor121and an associated memory122that stores a flow measurement algorithm and a transceiver125, which collectively provides an ultrasonic computer-based electronic flow measuring system that is coupled to the transducers101,102,103and104for causing the transducers to transmit ultrasonic signals and for analyzing received sensing signals generated by other transducers to determine a volume flow of a fluid flowing through the hybrid flowmeter100. As used herein, a transducer can include a separate transmitter and receiver. Other flow electronics module electronics, such as signal amplifiers, filters, an analog-to-digital converter (ADC, in the receive circuitry) and digital-to-analog converter (DAC, in the transmit circuitry) are generally part of flow electronics module120, but are not shown to provide simplicity. For every transmitted ultrasonic signal either a receiver of a direct-path or a receiver in reflective path can be active. It is also possible to receive signals from one or more direct-paths and one or more reflective paths simultaneously.

Hybrid flowmeter100can measure the flow velocity of the fluid flowing therethrough using the transit times of ultrasonic pulses, and flow electronics module120can calculate the flow rate at measurement conditions therefrom. Used is the fact that ultrasonic pulses move faster in the direction of flow than in the opposite direction against the flow.

During operation, each of the transducers101,102,103and104generally function as both an emitter (transmitter) and a receiver. Measurements are taken alternatively in both directions, so that after a transit time has been measured, an emitter becomes the receiver and vice versa. In this way, the impact of the velocity of sound which depends on the fluid type, pressure and temperature is eliminated.

Advantages of disclosed hybrid flowmeters such as hybrid flowmeter100which combine direct-path and reflective path sensing include increasing the total number of measurement paths without increasing the number of transducers, and providing a combination of different measurement (direct and reflective) methods in one flowmeter body. In addition, better swirl reduction is provided when using the reflective path-arrangement, and double sampling on different positions is also provided with each ultrasonic pulse.

In order to take the flow profile of the fluid in the pipeline into account, as known in the art measurements can be taken using a plurality of different sensing planes.FIG. 2Ais a perspective depiction of an example hybrid flowmeter200having three sensing planes each including four transducers positioned in a parallelogram arrangement on the meter pipe wall105a, according to an example embodiment. The reflectors on each sensing plane are not shown (seeFIGS. 2B-2Edescribed below). The direct sensing paths for the respective planes total 6 and are shown as paths1and2, paths3and4, and paths5and6. Connection flanges108having the meter pipe wall105atherein are shown on each end of the hybrid flowmeter200for bolting the hybrid flowmeter200to a pipeline.

FIG. 2Bprovides a width-wise cross-sectional depiction of the example hybrid flowmeter200shown inFIG. 2A, with the first sensing plane (first plane)200a, second sensing plane (second plane)200band third sensing plane (third plane)200c, each sensing plane including four transducers positioned in a parallelogram arrangement on a meter pipe wall, according to an example embodiment. For simplicity, the flow electronics module120and meter body105shown inFIG. 1are not shown inFIGS. 2B-2E. InFIG. 2B, the first plane200ashows transducers102,104and reflector112, the second plane200bshows transducers142,144and reflector152, and the third plane200cshows transducers162,164and reflector172.

The arrangement of direct-paths are generally according to Gauss-Chebyshev which provides high quality measurements of the flow velocity even in the case of asymmetries, swirl and crossflows. In addition, these variations of the ideal flow profile can also be measured, so that for example a flow diagnosis can be rendered.

FIG. 2Cis a length-wise cross sectional depiction of the example hybrid flowmeter200shown inFIG. 2A. The inner diameter of the meter pipe wall105ais shown ad Di. Being in a rectangular arrangement the direct-paths are shown making a 90 degree angle to one another, but as disclosed above can be at other angles, such as between 60 and 70 degrees to one another.

Disclosed transducers can be directly attached to the meter body105of the hybrid flowmeter such as through flanges (not shown). The position of the transducer tips in relation to the meter pipe wall105acan vary so that the transducer tips can be recessed from or also extend into the meter pipe. It is not necessary that the position of the planes is symmetrical to the axis of the meter body105.

FIG. 2Ddepicts the first plane200a(plane1) of the hybrid flowmeter200showing all four transducers101,102,103and104in a parallelogram arrangement on the meter pipe wall105aas well as both of its reflectors111and112.FIG. 2Edepicts the second plane200b(plane2) of the hybrid flowmeter200showing all four transducers141,142,143and144in a parallelogram arrangement on the meter pipe wall105aas well as both of its reflectors151and152. In this embodiment, the reflectors151,152are optional since only when a path does not cross the center axes of the meter body, a reflector is generally necessary, as signals which are reflected in the center plane will typically have a low scattering effect.FIG. 2Fdepicts the third plane200c(plane3) of the hybrid flowmeter200showing all four transducers161,162,163and164in a parallelogram arrangement on the meter pipe wall105aas well as both of its reflectors171and172.

FIG. 3Adepicts a sensing plane300of a hybrid flowmeter that is shown having transducers221a,222a,223a, and224aand reflectors311and312combining 2 multi-reflective paths (3 reflections each) shown as321and322, and 2 direct-paths shown as323and324. In comparison, the sensor planes described above, such as the first plane200a, second plane200b, and third plane200cof the hybrid flowmeters200described above, each provide 2 single-reflective paths and 2 direct-paths.

FIG. 3Bdepicts a sensing plane340of a hybrid flowmeter that combines 2 single-reflective paths shown as361and362, 2 multi-reflective paths shown as363and364, and 2 direct-paths shown as365and366. In this embodiment the transducers221a,222a,223a, and224ahave radiation characteristics configured to transmit a wide angle of transmission ultrasonic beam to provide the respective reflective paths along with the direct-paths shown.

As demonstrated above byFIGS. 3A-3B, by favoring the angles of the transducers for the simple reflective path arrangement it is possible to double the reflective path arrangement, to obtain a W/M multi-reflective path arrangement without the loss of the direct direct-paths. A path multiplication by 3 is shown as being possible. Further path multiplications are obtainable depending on the radiation characteristics of the transducers.

FIG. 3Cdepicts an inner sensing plane370(e.g. plane2in a 3 plane hybrid flowmeter) of a hybrid flowmeter that combines 2 single-reflective paths shown as381and382, 2 multi-reflective paths shown as383and384, and 2 direct-paths shown as385and386. In this embodiment the reflectors311and312shown inFIGS. 3A and 3Bare not needed due to signals in the center plane having as low scattering effect, and the transducers221b,222b,223b, and224bin sensing plane340inFIG. 3Beach transmit a wide angle of transmission ultrasonic beam to allow the single reflective paths, multi-reflective paths along with the 2 direct-paths.

FIG. 4depicts an inner sensing plane400(e.g. plane2in a 3 plane embodiment) of a hybrid flowmeter having transducers221c,222c,223c, and224cthat combines the 2 single-reflective paths381and382, 2 multi-reflective paths383and384, and 2 direct-paths385and386shown inFIG. 3C, along with 2 additional 0°-direct-paths, according to an example embodiment. Advantages of including 0° paths include enabling further diagnostics including measuring the speed of sound or to calculate the path arrangements (path length, axial distance) with a linear equation system.

Reception of either direct or reflected signals can generally be realized using existing flowmeter electronics. For the simultaneous reception of both direct and reflected signals the ultrasonic meter electronics can be extended to include known multi-receiver signal processing functionality, such as one receiver for receiving direct signals and one receiver for receiving reflected signals. Time division multiplexing (TDM) may also be used to enable a single receiver to receive both direct signals and reflected signals.

Disclosed hybrid sensing can be extended from a single plane to any number of planes. Disclosed hybrid flowmeters have several significant advantages. One advantage is realizing additional reflective path meters in a direct-path arrangement without the need for any additional transducers. Applied to custody transfer meter applications, disclosed hybrid flowmeters provide the advantage of extending the recalibration period which can provide a decreased number of needed recalibrations in a flowmeter lifetime. Recalibration is known to be a cost intensive process for the customer because the flowmeter has to be demounted from the pipeline and then sent to a calibration lab. Another advantage is by adding a check reflective path or multiple redundant reflective paths to a direct-path arrangement leads to increased meter accuracy when additional flow data obtained from the redundant flowmeter paths provided is included in main flow measurement.

While various disclosed embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Numerous changes to the subject matter disclosed herein can be made in accordance with this Disclosure without departing from the spirit or scope of this Disclosure. In addition, while a particular feature may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.