Rosemount 8800 Vortex Installation Effects

1 Technical Data Sheet00816-0100-3250, Rev HBOctober 2018 Rosemount 8800 Vortex Installation Effects2 ContentsChapter 1 Introduction .. Temperature Effects on K-factor .. Pipe ID Effects on K-factor .. Upstream and downstream piping configurations .. In plane versus out of plane .. 6 Chapter 2 Correcting the output of the Vortex meter .. Fieldbus and HART software revisions or earlier .. HART software revisions or and later .. Correction factor examples .. 13 Chapter 3 Calculating upstream and downstream pipe diameters .. 21 Technical Data Sheet Contents00816-0100-3250 October 2018 Technical Data sheet 3 Contents Technical Data SheetOctober 201800816-0100-32504 Rosemount 8800D Safety Manual1 IntroductionThe Rosemount 8800 Vortex Flowmeter provides methods for maintaining accuracy inless than ideal designing the 8800 , Emerson tested the meter for three separate types of installationeffects: Process fluid temperature variation Process piping inside diameter Upstream and downstream disturbancesAs a result of this testing, compensation factors are included in the Vortex meter software.

2 This allows the output of the Vortex meter to be adjusted for the actual processtemperature and process piping being is presented in this paper to demonstrate the effectiveness of the design in limitingthe errors resulting from piping disturbances. For upstream disturbances caused by pipeelbows, contractions, expansions, etc., Emerson has conducted extensive research in aflow lab to determine the effect that these have on the meter output. These tests are thebasis for the recommended 35 upstream piping diameters. While this is optimal, it is notalways possible in the real world of plant design and layout. Therefore, the data presentedin this paper outlines the Effects of different upstream and downstream piping conditionson the Vortex Effects on K-factorThe Vortex flowmeter is fundamentally a velocity measuring device.

3 As fluid flows past theshedder bar, vortices are shed in direct proportion to the fluid velocity. If the processtemperature is different than the reference calibration temperature, the flowmeter borediameter will change slightly. As a result, the velocity across the shedder bar will alsochange slightly. For example; an elevated process temperature will cause an increase inthe bore diameter, which in turn will cause a decrease in the velocity across the the Reference K-factor and the value for Process Temperature input by the user, theRosemount 8800 automatically calculates for the effect of temperature on the flowmeterby creating what is called the Compensated K-factor. The Compensated K-factor is then usedas the basis for all flow ID Effects on K-factorAll Rosemount 8800 Vortex Flowmeters are calibrated in schedule 40 pipe.

4 From extensivetesting done in piping with different inside diameters/schedules, Emerson has observedthere is a small K-factor shift for changes in process pipe ID (inside diameter). This is due tothe slight change in velocity at the inlet to the changes have been programmed in to the 8800 electronics and will be corrected forautomatically when the user supplied pipe ID is other than schedule Data Sheet Introduction00816-0100-3250 October 2018 Technical Data sheet and downstream pipingconfigurationsThe number of possible upstream and downstream piping configurations is , it is not possible to have software automatically calculate a correction factor forchanges in upstream piping. Fortunately, in almost all cases, elbows, reducers, etc. causeless than a shift in the flowmeter output. In many cases, this small effect is not a largeenough shift to cause the reading to be outside of the accuracy specification of shifts caused by upstream piping configurations are basically due to the changes inthe inlet velocity profile caused by upstream disturbances.

5 For example, as a fluid flowsaround an elbow, a swirl component is added to the flow. Because the factory calibration isdone in a fully-developed pipe flow, the swirl component caused by the elbow will cause ashift in the Vortex flowmeter output. Given a long enough distance between an elbow andthe flowmeter, the viscous forces in the fluid will overcome the inertia of the swirl andcause the velocity profile to become fully-developed. There rarely is sufficient length inactual process piping installations for this to occur. Even though the flow profile may notbe fully-developed, testing indicates that the Rosemount Vortex flowmeter can be locatedwithin 35 pipe diameters of the elbow with minimal effect on the accuracy or repeatabilityof the the upstream disturbance may cause a shift in the K-factor, the repeatability ofthe Vortex flowmeter is normally not affected.

6 For example, a flowmeter 20 pipediameters downstream of a double elbow will be as repeatable as a flowmeter in a straightpipe. Testing also indicates that while the K-factor is affected by upstream piping, thelinearity of the flowmeter remains within design many applications, this means that no adjustment for piping configuration will benecessary even when the minimum recommended Installation lengths of upstream anddownstream piping cannot be the following pages are drawings illustrating various Installation testing has been performed in a flow lab with these specific configurations. Theresults of those tests are shown as a series of graphs indicating the shift in the mean K-factor for a Vortex flowmeter placed downstream of a flow plane versus out of planeIn the graphics, the terms in plane and out-of-plane are used.

7 A butterfly valve and a vortexflowmeter are considered to be in plane when the shaft of the valve and the shedder bar ofthe Vortex flowmeter are aligned ( both the shaft and the shedder bar are vertical.) A butterfly valve and a Vortex flowmeter are considered to be in plane when the shaft ofthe valve and the shedder bar of the Vortex flowmeter are aligned ( both the shaftand the shedder bar are vertical). They are considered out of plane the shaft andshedder bar are offset by 90 .Introduction Technical Data SheetOctober 201800816-0100-32506 Rosemount 8800D Safety ManualFigure 1-1: Butterfly valveABA. In planeB. Out of plane An elbow is considered in plane when the shedder bar and elbow are aligned. The elbowis considered out of plane when the shedder bar and elbow are rotated 90 .Figure 1-2: Single elbowABA.

8 In planeB. Out of planeSimilarly, double elbows are in plane when the are both aligned with the shedder bar andout of plane when they are not aligned with the shedder Data Sheet Introduction00816-0100-3250 October 2018 Technical Data sheet 7 Figure 1-3: Double elbow same planeABA. In planeB. Out of planeIntroduction Technical Data SheetOctober 201800816-0100-32508 Rosemount 8800D Safety Manual2 Correcting the output of the vortexmeterCorrection factors can entered into the Vortex flowmeter transmitter using AMS DeviceManager, ProLink III v3 or a 475, AMS Trex(TM), or similar HART Field all Fieldbus devices and devices with HART software revisions and earlier, the K-factor can be adjusted using the Installation effect command. This command will adjust thecompensated K-factor to account for any correction needed.

9 The correction will beentered as a percentage of the K-factor shift. The possible range of the shift is + devices with HART revision or and later, the correction factor will beentered using the Meter Factor command. This command works in a similar way to theInstallation effect command but has an inverse relationship to k-factor shift and an enter-able range of to Entering a value of represents a +20% shift in k-factor, a valueof represents a 0% shift in k-factor, and a value of represents a -20% shift in and HART software revisions orearlierUsing AMS Device ManagerUnder the Sensor tab, enter the correction in the Install effect 2-1: Using AMS Device ManagerTechnical Data Sheet Correcting the output of the Vortex meter00816-0100-3250 October 2018 Technical Data sheet 9 Using a 475 HART Field CommunicatorGo to Manual Setup > Sensor > Process > Installation effect and then enter thecorrection number in the 2-2.

10 Using a 475 HART Field CommunicatorUsing ProLink IIITo enter the Installation effect , select Device Tools > Configuration > Device Setup > Installation the output of the Vortex meter Technical Data SheetOctober 201800816-0100-325010 Rosemount 8800D Safety ManualFigure 2-3: Using ProLink software revisions or and laterUsing AMS Device ManagerUnder the Sensor tab, enter the correction in the Meter Factor field. See Figure Data Sheet Correcting the output of the Vortex meter00816-0100-3250 October 2018 Technical Data sheet 11 Figure 2-4: Using AMS Device ManagerUsing a 475 HART Field CommunicatorGo to Manual Setup > Sensor > Process > Meter Factor and then enter the correctionnumber in the 2-5: Using a 475 HART Field CommunicatorUsing ProLink IIITo enter the Installation effect , select Device Tools > Configuration > Device Setup >Meter the output of the Vortex meter Technical Data SheetOctober 201800816-0100-325012 Rosemount 8800D Safety ManualFigure 2-6: Using ProLink factor examplesExample 1 The 8800 Vortex flowmeter is installed 15 pipe diameters downstream from a single 90 elbow, with the shedder bar in plane.