Q-Sonic Plus Technology Advances

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1 Q-Sonic Plus Technology Advances Prepared by: Charles Derr, Elster/Instromet The Q-Sonic Plus is a technology improvement over previous Instromet meters and a significant improvement over the world fleet of multi-path Ultrasonic Meters (Usms). We will, herein, explain the background hardware, measurement improvements, software and firmware superior points in order to verify the background for this bold statement. The Six Path Q-sonic Plus is comprised of 4 double-reflective paths and 2 single reflective paths. This yields 16 different mathematical chord slices of velocity information. (6 more than Krohne, 10 more than Honeywell, 12 more than Daniel, 12 more than FloSick600, 12 more than Cameron).

2 This Public Web Site picture below shows a four path, 4 Chord Meter sectioned view graphical representation. This yields four velocity zone Chordal slices of the total velocity profile. Example only: If this meter did 20 shoot-arounds /sec then you would have 80 velocity-chords/sec integrated into the average velocity integration. Four Paths Four Zones Four Beams Four Chords Four Velocity Slices Some Usm vendors routinely call each Chord, a Path. That is incorrect terminology but sounds like they have more paths than they do. A Chord is worth explaining in order to have the best grasp of what a Some meter Usm with vendors only a few call chords each Chord, vs a meter a Path. with That many is incorrect more chords has terminology as inputs for but its sounds ability to like integrate they have virtually more paths all of the than flow they velocity do. A Chord gradient is worth zones explaining inside the in measurement order to have section the best of grasp the meter of what body. a

3 Chord History/Example/Definition: Chords were used extensively in the early development of trigonometry. The first known trigonometric table, compiled by Hipparchus, tabulated the value of the chord function for every 7.5 degrees. In the second century AD, Ptolemy of Alexandria compiled a more extensive table of chords in his book on astronomy, giving the value of the chord for angles ranging from 1/2 degree to 180 degrees by increments of half a degree. The circle was of diameter 120, and the chord lengths are accurate to two base-60 digits after the integer part. The chord function is defined geometrically as in the picture to the left. The chord of an angle is the length of the chord between two points on a unit circle separated by that angle. The chord function can be related to the modern sine function, by taking one of the points to be (1,0), and the other point to be (cos, sin ), and then using the Pythagorean theorem to calculate the chord length:

4 A Usm Path is the geometric route and distance (whether it changes directions enroute or not) between two transducers that are a communication (transmit and receive) Pair. An ultrasonic frequency transfers from the Piezo crystal to the titanium face of the transducer to the gas and emits an ultrasonic sound pressure wave (measured in Micro-pPascals of sound pressure; which travels through the gas and arrives at the companion transducer face that it is acoustically aimed at by direct aim or by reflective aim. Any two points of tangency within the elongated circle of the cylinder comprising the measurement-section barrel of the meter body, when connected by a straight line, is one Chord or mathematical slice of that cylinder and in Usm measurement terms; one velocity-chord. The Q-sonic Plus has 4 double-reflective paths of 3 chords each giving 12 slices of the flow within the measurement section. The 2 singlereflective transducer pairs each have one path and 2 chords, (another 4 chords). This yields 16 total chords on each meter during its sequential activation of all 6 paths employing 6 pairs of transducers. Thus, one shoot-around sees 16 pieces of the flow profile distribution within the meter measurement section. Whether a multipath Usm is a take-off of the original expired British Gas or Westinghouse-2 patents, or others, the 4 path point-to-point meters see 4 total slices of the profile velocity distribution. At 30 complete shoot arounds per second (and16 chords), each second the Q-sonic Plus totalizes a velocity distribution integration of 480 Chord velocity-sectors! The three-dimensional flow velocity dynamics of pipeline Turbulent flow is better dimensionalized by the most angles viewed the fastest. This is three, (chord count/zones, chord lengths and timing resolution), of several very fundamental reasons for the inherent accuracy of the Q-sonic Plus, however, there are several others.

5 Four path and dual 4 path meters on the market range from 10 to 60+ shoot-arounds per second. 4 chords * 10 is 40 Chord velocity-sectors/sec. 4 Chords * 60 shoot-arounds per second is a total of 240 Chord velocity-sectors/sec., (however, they are still constrained by 4 chords as opposed to 16 chord sectors). 16 velocity-zones of the flow distribution profile yields more information than 4 velocity-zones. Another consideration of final accuracy in a Usm is its ability to accurately measure speed of sound. The speed of sound has a two to one error factor vs velocity. A one percent error in the measurement of speed of sound equals a two percent error in velocity and resultantly the average velocity and when multiplied by the meter area; Actual Volume Rate! Below are two (very typical for the Q-Sonic Plus series) recent certified calibration report/graphs of speed of sound as found on these meters:

6 Usms have a finite time base resolution, (the smallest increment of time that they are capable of measuring). The +/- time resolution capability is a constant increment for a given meter s applied technology and crystal time base design. The Path transit time, +/- the time base resolution gives the accuracy of the real transit time measurement. The Q-sonic Plus has four double reflection paths giving four LONG path lengths. Each double reflective path length is approximately 3X the length of a point-to-point direct path, for the same given diameter meter. This means that the time base accuracy +/- applied to each transit time measurement is only appr. 1/3 rd of the error in transit time; resulting in VERY accurate Speed of Sound measurements and incrementally; transit time measurement.

7 Examine the data sheet below for one 12 Qsonic Plus meter. Observe that the double-reflective paths are appr feet; or, 34 inches. Most 12 point-to-point meters would have a longest path of 11 to 12 inches. Having 3X the path length gives much better transit time resolution, therefore speed of sound accuracy, therefore final average velocity accuracy and finally; better volume accuracy. 12 Qsonic Plus Spool data below: Note: LONG path lengths for a 12 meter giving HIGH resolution of SOS/transit time The following is a recent calibration of a Q-sonic Plus:

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9 Meter Details: Certificate Number: 6275 Meter Serial Number 7407 Manufacturer Elster-Instromet Model Qsonic-Plus Meter I.D in meters Meter Capacity acf/h acm/h Flow Conditioner CPA 50E Type A Test Conditions(Avg) Natural Medium Gas Pressure psia kpa Temperature F C Density 2.76 lbs/ft kg/m 3 Compressibility The table below is the actual As Found Measured vs- AGA 10 Calculated Speed of Sound SOS Comparison [Meter vs AGA-10] FlowRate Gas Velocity Meter SOS Calc. SOS SOS Deviation SOS Deviation (m3/hr) (m/s) (m/s) (m/s) (m/s) (%)

10 SOS Deviation [Units in table] SOS Comparison [Meter vs AGA-10] Gas Velocity [Units in table] Precise timing gives a Usm only Precision...then: Repeatable timing gives a Usm.Precise repeatable timing.then: Linearity gives near-same small error across the range..then : Calibration factors bring each calibrated velocity to the accuracy point of the calibration reference system adding up to: A Precise, Repeatable, Linear, Accurate Meter The data above is the result of 6 paths, 16 chords, 2 long and 4 very long paths; running 16 chords at 30 hz and yielding 480 velocity-chords/sec, measured. This is where a large portion of the Inherent Accuracy is originated. This is an amazing Natural Linearity or out-of-the-box Linearity and is a common calibration test result, for the Q-Sonic Plus series.

11 Shown below is a Q-Sonic Plus with the protective stainless wire covers removed, the transducer and block and cable installed, the onboard pressure transducer installed, the explosion-proof 7-data group color touchscreen local display and a Transmitter with the CPU, et. Shown inside a plexi-glass depiction of the standard aluminum or stainless canister.

12 The Titanium Encapsulated, Low power, Intrinsically Safe Transducers as shown installed (above) are a great part of the Q-Sonic Plus Success Story as are the 90 degree ports having no pocket turbulence scooping effect. These Hardware Differentiators are vitally important: especially so when combined with Advanced Signal Processing! The Q-Sonic Plus employs Very Highly Advanced Signal Processing: The Coded Multi Burst is a Signal Processing Advantage in High Ultrasonic Noise Backgrounds (Caused by Valves, Regulators, Etc.): Traditional Methods of Noise reduction Averaging / Stacking Improvement of SNR when the noise is asynchronous No improvement of SNR when noise is synchronous Transit times variation (jitter) causes signal blurring Filtering Improves SNR for out of frequency band noise Does not help when noise is in frequency band

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15 Coded Multi Burst with and without noise

16 Coded Multiple Burst Improvement of signal to noise (High speed averaging in combination with a unique code) Without any delay (Efficiently usage of UFM operating time) Requires transducer with broad band characteristics (Coded signal cannot pass through narrow band transducer) Very special transducers are needed to do high speed Coded Multi Burst they must be broad band, fast and have a fast (low) delay time. The transducer design accomplished for the Q-Sonic Plus is the new Raised-Bar for others to reach for in the future; but are the standard for all current production Elster/Instromet Usms. They are a true advanced technology.

17 Deviation [%] The Majority of the Usm Fleet Technique As found As left Ver Pt1 Ver Pt2 I.E: 60 Deg Sharp-edged ovalentry port causes pocket-turbulence Transducer Port boreentry Cross-sectional view Flow Q-Sonic Plus Technique Small, low volume, 90 Deg port gives exceedingly small pocket-turbulence