System and method for quantitative verification of flow measurements

Abstract

A flow meter system and method measures fluid flow in a conduit. The conduit has a conduit axis. The flow meter includes a sensor configured to provide measurement data relating to the volumetric or mass flowrate though the conduit, and a processor configured to determine flow per unit time in the conduit using the measurement data, an uncertainty measurement per unit time using the measurement data, and an uncertainty quantity using the uncertainty measurement per unit time. The uncertainty quantity is totaled over a time period.

What is claimed is: 
     
         1 . A flow meter system for measuring fluid flow in a conduit having a conduit axis, the flow meter system comprising:
 a sensor configured to provide measurement data;   a processor configured to determine:   flow in quantity units per unit time in the conduit using the measurement data   at least one uncertainty value in quantity units per unit time using the measurement data,   at least one uncertainty quantity using the uncertainty value per unit time, wherein the uncertainty quantity is totaled over a time period.   
     
     
         2 . The flow meter system of  claim 1  wherein quantity units are in mass or volume. 
     
     
         3 . The flow meter system of  claim 1  wherein the sensor comprises ultrasonic transducers in one or more chordal measurement planes, wherein transducer pairs located in each chordal measurement plane are positioned to form acoustic transmission paths that traverse at least once from one side of the chordal measurement plane to another side of the chordal measurement plane, each traverse is either direct from one transducer to another or via one or more reflection points and whereby a plurality of axial velocity measurements are made in each chordal plane with a minimum of three traverses in each chordal plane, each chordal plane is in parallel with the conduit axis. 
     
     
         4 . The flow meter system of  claim 1 , wherein the one uncertainty value in quantity units per unit time comprises a number of first measurements each associated with a unique chordal plane. 
     
     
         5 . The flow meter system of  claim 4 , wherein each of the first measurements are converted to respective first quantities. 
     
     
         6 . The flow meter system of  claim 5 , wherein the first quantities are totalized. 
     
     
         7 . An ultrasonic flow meter system for measuring fluid flow in a conduit having a conduit axis, the ultrasonic flow meter system comprising:
 multiple transducer pairs positioned to form acoustic transmission paths that are co-located in one or more chordal measurement planes in each chordal measurement plane; and   a processor configured to determine flow per unit time in the conduit using the axial velocity measurements, an uncertainty measurement per unit time using the axial velocity measurements, and an uncertainty quantity using the uncertainty measurement per unit time, wherein the uncertainty quantity is totaled over a time period.   
     
     
         8 . The ultrasonic flow meter system of  claim 7 , wherein the uncertainty measurement is related to differences in the axial velocity measurements in each chordal plane. 
     
     
         9 . The ultrasonic flow meter system of  claim 7 , wherein the multiple transducer pairs located in the chordal measurement plane are positioned to form acoustic transmission paths that traverse at least once from one side and whereby a plurality of axial velocity measurements is made in each chordal plane with a minimum of three traverses in each chordal plane, each chordal plane is in parallel with the conduit axis, and comprising two paths per chordal plane, each path being a reflected path with two traverses of the chordal plane and one reflection in each of the two paths. 
     
     
         10 . The ultrasonic flow meter system of  claim 9 , comprising three paths per chordal plane and transmission on two paths is direct between transducers, and one path is a reflected path with two traverses of the chordal plane and one reflection point. 
     
     
         11 . The ultrasonic flow meter system of  claim 7 , wherein the uncertainty measurement per unit time comprises a number of first measurements each associated with a unique chordal plane. 
     
     
         12 . The ultrasonic flow meter system of  claim 11 , wherein each of the first measurements are converted to respective first quantities. 
     
     
         13 . The ultrasonic flow meter system of  claim 12 , wherein the first quantities are totalized. 
     
     
         14 . The ultrasonic flow meter system of  claim 7 , wherein the multiple transducer pairs located in the chordal measurement plane are positioned to form acoustic transmission paths that traverse at least once from one side and whereby a plurality of axial velocity measurements is made in each chordal plane with a minimum of three traverses in each chordal plane, each chordal plane is in parallel with the conduit axis, wherein two nodes are each shared by two paths and a total number of nodes can be reduced from six to four or from seven to five. 
     
     
         15 . The ultrasonic flow meter system of  claim 7 , wherein the multiple transducer pairs located in the chordal measurement plane are positioned to form acoustic transmission paths, wherein three nodes are each shared by two paths and a total number of nodes can be reduced from seven to four. 
     
     
         16 . The ultrasonic flow meter system of  claim 7 , wherein the multiple transducer pairs located in the chordal measurement plane are positioned to form acoustic transmission paths that traverse at least once from one side, wherein two nodes are each shared by two paths and a third node is shared by three paths and a total number of nodes can be reduced from seven to three. 
     
     
         17 . The ultrasonic flow meter system of  claim 7 , wherein the multiple transducer pairs located in the chordal measurement plane are positioned to form acoustic transmission paths, wherein the acoustic transmission paths in each chordal plane overlap. 
     
     
         18 . A method for measuring fluid flow in a conduit with a flow meter, the flow meter comprising multiple transducer pairs positioned with respect to conduit acoustic transmission paths, the method comprising:
 providing an axial velocity measurement;   providing a flow per unit time in the conduit using the axial velocity;   providing an uncertainty measurement per unit time using the axial velocity measurement for each chordal plane; and   providing an uncertainty quantity using the uncertainty measurement per unit time; and   providing a total uncertainty quantity for a time period.   
     
     
         19 . The method of  claim 18 , further comprising:
 determining fluid flow in the conduit from the axial velocity measurement.   
     
     
         20 . The method of  claim 18 , comparing the total uncertainty quantity or the uncertainty quantity to a threshold to determine a fault. 
     
     
         21 . A flow meter system for measuring fluid flow in a conduit, the flow meter system comprising:
 a sensor configured to provide measurement data;   a processor configured to determine:   flow in the conduit using the measurement data   at least one uncertainty value in quantity units per unit time using the measurement data,   at least one uncertainty quantity using the uncertainty value per unit time, wherein the uncertainty quantity is totaled over a time period.   
     
     
         22 . The flow meter of  claim 21 , wherein two composite velocities are calculated using the axial velocity values from multiple chordal planes sensed by the sensor, with each of the two composite velocities being calculated using different chordal integration schemes, wherein the difference between the first and second composite velocities is used in the determination of the uncertainty value. 
     
     
         23 . The flow meter of  claim 21 , wherein the sensor comprises at least one of an: ultrasonic, Coriolis, electromagnetic, differential pressure, thermal, vortex shedding, cross-correlation, capacitance, microwave, temperature, pressure, or density sensor. 
     
     
         24 . The flow meter of  claim 21 , wherein the sensor use a reflected ultrasonic path to determine of an area uncertainty value, wherein the area uncertainty value is combined with a velocity result to yield an area related uncertainty in units of volume per time, wherein the area uncertainty value is totalised in units of volume.