AGA Report 7 2006 PDF

(1)

easurement o

atura as y

,---..,

o

n

1115191510161

j

1 171

1 ~

"r

1 v ....

~

U

I \

1"

L

(2)

AGA Report No. 7

Measurement of Natural Gas

by Turbine Meters

Revised

February 2006

Prepared

by

Transmission Measurement Committee

Adh.

American Gas Association

400 North Capitol Street, NW, 4th Floor, Washington, DC 20001, U.S.A. Phone: (202) 824-7000 • Fax: (202) 824-7082 • Web: www.aga.org

(3)

DISCLAIMER AND COPYRIGHT

The American Gas Association's (AGA) Operating Section provides a forum for industry experts to bring collective knowledge together to improve the state of the art in the areas of operating, engineering and technological aspects of producing, gathering, transporting, storing, distributing, measuring and utilizing natural gas.

Through its publications, of which this is one, the AGA provides for the exchange of information within the gas industry and scientific, trade and governmental organizations. Each publication is prepared or sponsored byan AGA Operating Section technical cornmittee. While AGA may adrninister the process, neither the AGA nor the technical cornmittee independently tests, evaluates, or verifies the accuracy of any information or the soundness of any judgments contained therein.

The AGA disc1aims liability for any personal injury, property or other damages of any nature whatsoever, whether special, indirect, consequential or compensatory, directly or indirectly resulting from the publication, use of, or reliance on AGA publications. The AGA makes no guaranty or warranty as to the accuracy and completeness of any infonnation published therein. The infonnation contained therein is provided on an "as is" basis and the AGA makes no representations or warranties including any express or implied warranty of merchantability or fitness for a particular purpose,

In issuing and making this document available, the AGA is not undertaking to render professional or other services for or on behalf of any person or entity. Nor is the AGA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances.

The AGA has no power, nor does it undertake, to poli ce or enforce compliance with the contents ofthis document. Nor does the AGA list, certify, test, or inspect products, designs, or installations for compliance with this document. Any certification or other statement of compliance is solely the responsibility of the certifier or maker of the statement.

The AGA does not take any position with respect to the validity of any patent rights asserted in connection with any items which are mentioned in or are the subject of AGA publications, and the AGA disc1aims liability for the infringement of any patent resulting from the use of or reliance on its publications. Users of these publications are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility.

U sers of this publication should consult applicable federal, state, and local laws and regulations. The AGA does not, through its publications intend to urge action that is not in compliance with applicable laws, and its publications may not be construed as doing so.

This report is the cumulative result of years of experience of many individual s and organizations acquainted with the measurement of natural gas. However, changes to this report may become necessary from time to time. If changes in this report are believed appropriate by any manufacturer, individual or organization, such suggested changes should be cornmunicated to AGA by completing the last page of this report titled, "Form for Suggestion to Change AGA Report No. 7, Measurement of Natural Gas by Turbine Meters" and sending it to: Operations & Engineering Services Group, American Gas Association, 400 North Capitol Street, NW, 4th Floor, Washington, DC 20001, U.S.A.

(4)

FOREWORD

This report is published in the fonn of a perfonnance-based specification for turbine meter for natural gas flow measurement. It is the result of collaborative effort of natural gas users, turbine meter manufacturers, flow measurement research organizations and independent consultants fonning Task Group R-7 of AGA's Transmission Measurement Cornmittee (TMC). In addition, comments to this report were made by the Committee on Gas Flow Measurement (COGFM) of the American Petroleum Institute (API).

Research conducted in support of this report and cited herein has demonstrated that turbine meters can accurately measure natural gas and, therefore, should be able to meet or exceed the requirements specified in this report when calibrated and installed according to the recommendations contained herein. Users should followappropriate installation, use and maintenance ofturbine meter as applicable in each case.

This version of AGA Report No. 7 is intended to supersede aH prior versions of this document. However, this document does not reference existing turbine meter instaIlations. The deCÍsion to apply this document to existing instaHations shall be at the discretion of the parties involved. Appendix B of this report contains the equations needed to convert volume measured at actual (line) conditions to equivalent volume at base conditions, or to mass. These equations may be used to perform such calculations with any type of positive displacement or inferential meter that registers in units of volume.

(5)

ACKNOVVLEDGEMENTS

Report No. 7, Measurement 01 Natural Gas by Turbine Meters, was developed by a Task Group of the American Gas Association's Transmission Measurement Committee. Individuals who made substantial contributions to the creation of this document are:

Larry Fraser, Fraser & Associates (Chairman)

Angela Floyd, Panhandle Energy Dan Peace, Sensus Metering Systems

Mark Pelkey, National Fuel Alex Podgers, American Meter Co.

Research eondueted by Darin George, Ph.D., Southwest Research Institute at the Southwest Research Institute and the Colorado Experimental Engineering Station was instrumental in developing the seientific basis for the provisions of this Report.

Other individuals who contributed to the development ofthe doeument are: Ed Bowles, Southwest Researeh Institute

loe Bronner, Paeifie Gas and Eleetric Co. Jim Bowen, Instromet

Frank Brown, Consultant Steve Caldwell, CEESI Cary Carter, Texas Gas Transmission Craig Chester, Williams Gas Pipeline Philip DiGiglio, KeySpan Corporation Chuek French, Gas Technology Institute Gamet Grudeski, TransCanada Calibrations

Danny Harris, Columbia Gas lim Hagen, Great Lakes Gas Zaki Husain, Chevron Texaeo Mark Imboden, Controlotron Corp.

Jim Keating, Consultant

Erie Kelner, Southwest Researeh Institute ABen Knaek, Consumers Energy PauI LaNasa, CPL & Associates

John Lansing, Daniel M&C Rick Ledesma, El Paso Pipeline Group Brad Massey, Southem Star Central Gas Pipeline

George Mattingly, Consultant Dannie Mercer, Atmos Energy Corporation

Roy Meyer, Exxon Mobil Winston Meyer, CenterPoint Energy

Kevin Moir, DTE Energy John Naber, Daniel M&C Chris Overgaard, Nicor Gas Warren Peterson, TransCanda PipeLines

Thanh Phan, Duke Energy Reese Platzer, Questar Pipeline King Poon, Thermo Electron Corp.

(6)

Daniel Rudroff, Welker Flow Measurement Systems Ine. Blaine Sawchuk, Canada Pipeline Aeeessories

Bill Schieber, Solar Turbines Tushar Shah, Eagle Research Corporation

Jerry Paul Smith, Consultant Walt Seidl, CEESI Karl Stappert, Daniel M&C John Stuart, Stuart Consulting Jim Witte, El Paso Pipeline Group

AGA acknowledges the contributions of the aboye individuals and thanks them for their time and effort in getting this docurnent revised.

Lori Traweek

Senior Vice President

Ali Quraishi, StaffExecutive Engineering Services Director

(7)

6.1 INTEGRITY TEST ... 12 6.2 LEAKAGE TEST ... 12 6.3 CALIBRATION ... 12 6.3.1 Calibration Conditions ... 12 6.3.1.1 Reynolds Number. ... 12 6.3.1.2 Density ... 13 6.3.1.3 CalibrationGases ... 13 6.3.2 Calibration Guidelines ... 14 6.3.3 Calibration Configuration ... 14 6.3.4 Calibration Facilities ... '" ... 14 6.3.5 Calibration Results ... 14

(8)

6.3.5.1 Change Gears ... 14

6.3.5.2 K-Factor(s) ... 15

6.3.5.3 Meter Factors and Final Meter Factor.. ... 15

6.3.5.4 Rotor F actors for Dual-Rotor Meters ... 15

6.3.5.5 Meter Verification TesL ... 15

6.4 TEST REpORTS ...•... 16

6.5 QUALITY ASSURANCE ... 16

7. INSTALLATION SPECIFICATIONS •••••.•...•.•.••.••••.•••••••.••....••..•••••••••••••••••.•.• _ •••••••••••••••••••...•.••••..••••••••••• 17

7.1 GENERAL CONSIDERA TIONS ...•..•..•... 17

7.1.1 Flow Direction ... 17

7.1.2 Meter Orientation and Support ... 17

7.1.3 Meter Run Connections ... 17

7.1.4 Internal Surfaces ... 17

7.1.5 Temperature Well Location ... 17

7.1.6 Pressure Tap Location ... 18

7.1.7 Flow Conditioning ... 18

7.1.7.1 Tube Bundle Type Straigbtening Vanes ... 18

7.1.7.2 Other External Flow Conditioners ... 18

7.1.7.3 Integral Flow Conditioners ... 18

7.2 RECOMMENDED INST ALLA TION CONFIGURA TIONS ... 18

7.2.1 Recornmended Installation for In-Line Meters ... 19

7.2.2 Optional Installation Configurations for In-Line Meters ... 20

7.2.2.1 Short-Coupled Installation ... 20

7.2.2.2 Close-Coupled Installation ... 21

7.2.2.3 Meter-Integrated Flow Conditioning ... 22

7.2.3 Suggested Installation for Angle-Body Meters ... 23

7.3 ENVIRONMENTAL CONSIDERATIONS ... 24

7.3.1 Temperature ... 24

7.3.2 Vibration ... 24

7.3.3 Pulsations ... 24

7.3.4 Hydrate Formation and Liquid Slugs ... 24

7.4 ASSOCIATED DEVICES ... 24

7.4.1 Filtration and Strainers ... 24

7.4.2 Throttling Devices ... 25 7.5 PRECAUTIONARY MEASURES ... 25 7.5.1 Installation Resídue ... 25 7.5.2 Valve Grease ... 25 7.5.3 Over-Range Effects ... 25 7.5.3.1 Run Pressurization ... 25

7.5.3.2 Blow Down Precautions ... 26

7.5.3.3 Flow Limiting Devices ... 26

7.6 ACCESSORYINSTALLATION ... 29

7.6.1 Density Measurement Devíces ... 29

7.6.2 Volume Correctors and Instrumentation ... 29

8. METER MAINTENANCE AND FIELD VERIFICA TION CHECKS ... 30

8.1 GENERAL ... .30

8.2 VISUAL INSPECTION ... .30

8.3 CLEANING AND OILING ... 31

8.4 SPIN TIME TEST ... 31

8.5 DUAL-RoTOR METER FIELD CHECKS ... 33

(9)

APPENDIXA._ ... A-1

A.1 SINGLE ROTOR TURBINE METERS ...•... A-1

A.l.l GAsMETERDESIGN ... A-l A.l.2 LIQUIDMETERDESIGN ... A-2

A.2 DUAL-ROTOR TURBINE METERS ... _ ... A-2

A.2.l DUAL-RoTOR DESIGNS ... A-2 A.2.2 SECONDARY ROTOR DESIGNS ... A-S A.2.3 SECONDARY ROTOR FUNCTIONS ... A-S

A.3 DUAL-ROTOR METER ELECTRONICS ... A-5

APPENDIX B •.. _ ... _ ... B-1

B.1 EQUATIONS FOR CALCULATING VOLUMETRIC FLOW ... _ ... B-1

B.l.l BASICGASLAWS ... B-l B.l.2 FLOW RATE AT FLOWING CONDITIONS ... B-2 B.l.3 FLOWRATE AT BASE CONDITIONS ... B-2 B .1.4 PRESSURE MUL TIPLIER ... B-2 B.l.S TEMPERATURE MULTIPLIER ... B-3 B.l.6 COMPRESSIBILITY MUL TIPLIER ... B-3 B.l.7 EQUATIONS FOR METER RANGEABILITY ... B-3 B.l.7.l Maximum Flow rate ... B-3

B.2 EQUATIONS FOR CALCULATING MASS FLOW ... B-5

APPENDIX C ... C-I

C.I METER REGISTER READING ... C-1

C.2 ELECTRONIC COMPUTATION ... C-I

C.3 MECHANICAL INTEGRATING DEVICES ... C-1

CA PRESSURE, VOLUME AND TEMPERA TURE RECORDING DEVICES ... C-I

APPENDIX D ... D-I

D.I CHANGE GEARS ... D-I

D.2 K-FACTOR(S) ... D-2

D.3 METER FACTOR ... D-4

D.4 FINAL METER FACTOR ... D-8

D.5 ROTOR FACTORS FOR DUAL-ROTOR METERS ... 10

APPENDIX E ...•...•... E-l

E.1 REYNOLDS NUMBER AND FLOW RA TE MATCHING ... E-1

E.2 PRESSURE AND FLOW RATE MATCHING ...•... E-2

E.3 DENSITY AND REYNOLDS NUMBER MATCHING ... E-2

E.4 DENSITY AND FLOW RATE MATCHING ... E-2

E.s. EXAMPLE CALCULATIONS ... E-2 E.s.1 TO MATCH REYNOLDS NUMBERS AND FLOW RA TES ... E-3 APPENDIX F ...••...•...•.•... F-l

(10)

F.2 TESTING OUT OF LINE ...•...•... F-l

REFERENCE LIST ... _ ... REF-l

(11)

MEASUREMENT OF NATURAL GAS BY TURBINE METERS

1. Introduction 1.1 Scope

These specifications apply to axial-flow turbine flow meters for measurement of natural gas, typically 2-inch and larger bore diameter, in which the entire gas stream flows through the meter rotor. Typical applications include measuring single-phase gas flow found in

production, process, transmission, storage, and distribution and end-use gas measurement systems. Typical use is the measurement of fuel grade natural gas and associated hydrocarbon gases either as pure hydrocarbons or as a mixture of pure hydrocarbons and diluents. Although not within the scope of this document, turbine meters are used to measure a broad range of fluids other than natural gas.

This report does not address the characteristics of electronic pulse signal generating devices within or attached to the meter, although it does address the use oftheir outputs.

AIso not addressed are the characteristics of mechanical or electronic instruments that convert meter outputs from line conditions to base conditions. However, Appendix B do es contain the equations establishing the mathematical basis for the conversion process. Although these equations appear in this report, they may be used to convert volume registered by any type of meter.

1.2 Principie of Measurement

Turbine meters are inferentiaI meters that measure flow by counting the revolutions of a rotor, with blades, which turns in proportion to the gas flow velocity. From the geometry and dimensions of the rotor blades and flow channeI, for a particular turbine meter size and model, the gas volume at line conditions can be inferred trom counting the number of rotor revolutions. The revolutions are transferred into digital readout or electronic signals by sorne combination of mechanical gearing, generated e1ectronic or optical pulses, or frequency. The accumulated line volume can be converted to base volume at standard or contract conditions by accessory devices. Turbine meters can operate over a wide range of gas and ambient conditions. Their upper flow capacities are established and limited by maximum local internal gas velocities, noise generation, erosion, rotor speed, shaft bearing wear and pressure losses. The maximum flow capacity at line conditions is fixed for a particular turbine meter regardless of the operating pressure and temperature. The maximum base flow capacity increases in accordance with Boyle's and Charles' laws. Minimum flow capacities are limited by fluid and non-fluid drags (i.e., windage and mechanical friction los ses, respectively) that cause a particular turbine meter design to exceed the desired or prescribed performance limits.

(12)

2. Terminology

For the purposes ofthis report, the following definitions apply: Change gears

Designer Error

Final meter factor

K-factor

MAOP Manufacturer

Maximum peak-to-peak error

Measurement cartridge

Meter factor

A set of mating gears in the output gear train of sorne turbine meters that can be changed during the calibration process. A gear combination can be selected, with the appropriate ratio of teeth, to correct the mechanical output to reduce registration errors.

A company that designs and constructs metering facilities. The result of a measurement minus the true value of the measurand. Note: Since the true value cannot be determined, a value determined by means of a suitable reference meter is used.

% error = [(measured value - reference value) / reference

value] x 100%

A number developed either by averaging the sum of the individual meter factors over the range of the meter or by weighting more heavily towards the meter factors over flow rates at which the meter is more likely to be used. The value is used as a correction factor. In addition, multi-point linearization or polynomial curve fitting techniques may be used.

A number by which the meter's output pulses are multiplied to determine the volume through the meter. One or more factors may be used over a meter's operating range as determined by flow calibration results.

Maximum allowable operating pressure.

A company that designs, manufactures, sells and delivers turbine flow meters.

The difference between the largest and the smallest errors throughout the calibrated range of the meter.

An intemal assembly, removable from sorne meters, which ineludes the measurement components, but excludes the meter body.

A number by which the result of a measurement is multiplied to compensate for systematic error. The non-dimensional multiplying value is determined for each flow rate at which the meter is calibrated. The number is calculated by dividing the value from the reference meter by the indicated value of the

(13)

Operating range Pressure drop Q¡ Rangeability Reference meter Repeatability

meter under test. It can be applied to individual flow rates or averaged to provide a single factor (final meter factor) for the meter.

The range of ambient and flowing gas conditions over which the meter is designed to operate.

The permanent los5 of line pressure across the meter.

The flow rate through the meter under a specific set of test or operating conditions.

The maximum gas flow rate through the meter that can be measured within the specified performance requirements. The minimum gas flow rate through the meter that can be

measured within the specified performance requirement. The transition flow rate. The flow rate through the meter at

which performance requirements may change.

The ratio of the maximum to minimum flow rates over which the meter meets specified performance requirements (sometimes called "turndown ratio").

A meter or measurement device of proven flow measurement accuracy.

Cl05eness of the agreement between the results of successive measurements ofthe same measurand carried out under the same conditions of measurement.

Notes:

1. These conditions are called repeatability conditions. 2. Repeatability conditions inelude:

• The same measurement procedure • The same observer

• The same measuring instrument used under the same conditions

• The same location

• Repetition over a short period of time

3. Repeatability may be expressed quantitatively in terms of the dispersion characteristics ofthe results.

4. A valid statement of repeatability requires specifications of the conditions of measurement, such as temperature, pres-sure and gas composition.

(14)

Rotor factor

User

The number of output pulses per unit volume for individual rotores) provided by the meter manufacturer for use in a proprietary algorithm. Rotor factors are assocÍated with the electronic pulse output(s) from each rotor, typically of a dual-rotor turbine meter.

The individual or company that uses the turbine meter for measurement purposes.

(15)

3. Operating Conditions

3.1 Gas Quality

The meter should, as a minimum requirement, operate with any of the nonnal range natural gas composition mixtures specified in Table 1 of AGA Report No. 8, Compressibility Factors oi Natural Gas and Other Related Hydrocarbon Gases (Reference 1).

The manufacturer should be consulted if any of the following are expected:

• Operation near the hydrocarbon or water vapor dew point of the natural gas mixture. • Total sulfur levels exceeding 20 grains per 100 cubic feet, including mercaptans, H2S

and elemental sulfur compounds, or exceeding those specified in the National Association of Corrosion Engineers (NACE) guidelines for the materials ofwhich the meter is manufactured.

• Exposure to other contaminants that may affect the meter's error by reducing the cross-sectional f10w area or building up on other sensitive features. Deposits may also contaminate bearing lubrication and lead to reduced service life.

3.2 Operating Pressures

The operating pressure of the meter shall be within the range specified by the meter manufacturer. The manufacturer shall specify the maximum allowable operating pressure for the meter design and construction. Turbine meters, in general, do not have a minimum operating pressure limit, although error may be increased if used under conditions for which the meter has not been calibrated. Section 6 provides information on calibration requirements.

3.3 Temperatures, Gas and Ambient

The meter shall be used within the manufacturer's flowing gas and ambient air temperature specifications. Depending upon material of construction, turbine meters can operate over a f10wing gas and ambient temperature range of -40o_p _to₊_{165°P (-40°C to 74°C).}_It_is

important that the flowing gas temperature remain aboye the hydrocarbon dew point of the gas to avoid possible meter damage and measurement error. The manufacturer shall provide gas temperature and ambient air temperature specifications for the meter, as they may differ from the aboye.

3.4 Effect of Gas Density

Gas density can have three principal effects on the performance ofthe gas turbine meter: • Rangeability - The rangeability of a turbine meter increases as gas density increases. • Pressure Drop - The pressure loss across a turbine meter increases as the gas density

increases.

(16)

3.5 Gas Flow Rate Considerations

The manufacturer shall provide the operating flow rate range at various pressures. The user needs to consider the relationship between flow rate, error, pressure 10ss and service life. The performance requirements for operation are stated in Section 5.1 of this document. The pressure 10ss across a turbine meter increases with the square of a flow rate increase. Bearing lubrication or visual inspection frequencies may need to be adjusted in accordance with the operating flow rateo Flow limiting devices may be required to provide over-range protection for the meter. Designers and users are cautioned to evaluate noise, piping safety and meter integrity concems at maximum operating velocity. Refer to Section 7 of this document for more inforrnation on installation considerations.

3.6 Upstream Piping and Flow Profiles

Research was conducted on the effects of installation configuration on turbine meter error in 2002 and the results published in Reference 2, Section 7 provides inforrnation on installation requirements.

(17)

4. Meter Design Requirements

4.1 Codes and Standards

The meter body and a11 other parts eomprising the pressure eontaining struetures shall be designed and construeted of materials suitable for the service conditions for whieh the meter is rated and in aceordance with any applicable eodes, regulations and speeifieations of the designer. The meter body sha11 operate without leakage or pennanent defonnation over the expeeted range of operating pressures, flowing gas temperatures and environmental conditions.

4.2 Meter Body

4.2.1 Meter Body End Connections

The body end connections shaU be designed in accordanee with appropriate flange or threaded connection standards.

4.2.2 Corrosion Resistance

AH wetled parts of the meter shaU be manufaetured of materials suitable for use in their intended application. A11 external parts of the meter should be made of corrosion-resistant material s or sealed with a corrosion-resistant coating suitable for use in environmental conditions typically found in the natural gas industry aml/or as specified by the designer.

4.2.3 Meter Lengths and Bores

Manufacturers shaH publish their standard overa11 face-to-face length of the meter body for each meter size and pressure rating. Turbine rneters are genera11y tolerant of minor diameter differences, such as pipe schedule size changes. However, the designer sha11 make sure that the recommendations of Section 7 are followed.

4.2.4 Pressure Tap

The rnanufacturer shall provide at least one pressure tap on the meter body. The static pressure from the meter tap provided and identified by the manufacturer shall be used for pressure correction of the meter registration volume.

4.2.5 Sealing

The meter may be provided with sealing arrangements to prevent access to its internal working parts, adjustments and reprogramming. The sealing arrangements shall be such that they do not prevent access to routine maintenance features of the meter, such as lubrication points. Where measurernent cartridges are interchangeable, the means of sealing the cartridge shal1 be designed to prevent access to adjustment and reprogramming when the cartridge is removed from the meter body. Any means provided to seal the cartridge to the meter body sha11 be independent of any other sealing means provided. Independent seaJing sha11 al10w the body-to-cartridge seal to be removed without permitting access to the cartridge's intemal working parts or adjustments.

(18)

4.2.6 Miscellaneous

The construction shaIl be mechanicaIly and electricaIly sound, and the materials, finish, etc., should be such as to provide assurance of long life and sustained accuracy. The meter may provide one or more outputs (mechanical or e1ectrical), proportional to the volume of gas that has passed through it, expressed at line conditions of pressure and temperature.

The meter shaIl be designed in such a way that the body will not roIl when resting on a smooth surface with a slope ofup to 10 percent. The meter design shall al so permit easy and safe handling of the meter during transportation and installation. Threaded holes for hoisting eyes or clearance for lifting straps shall be provided.

4.3 Meter Markings

A name platee s) containing the fo11owing information shall be affixed to the meter • Manufacturer

• Model and size (intemal nominal díameter) • Serial number

• Date of manufacture or date code

• Maximum allowable operating pressure (MAOP) • Maximum rated capacity at flowing conditions • K-factor amI/or rotor-factor(s), if applicable Other markings on the meter sha11 indicate:

• Inlet end or direction of flow

• Direction of output shaft rotation, if applicable

• Units ofvolume per revolution ofthe output shaft, if applicable

• Material ofpressure containing components, (body, flanges, top plate, etc.) • Pressure reference tap (e.g., "PR," "Pr" or "Pm")

• Orientation of measurement cartridge, if applicable • Serial number of measurement cartridge, if applicable

4.4 Documentation

The manufacturer shall provide a11 necessary data, certificates and documentation for correct configuration, set-up and use of the particular meter upon request by the user or designer. The user or designer may also request that copies of hydrostatic-test or lcak-test certificates, material certifications and casting or weld radiographs be supplied with delivery of the meter.

(19)

The manufacturer shalI provide or make available the following documents with the meter or when requested; all documents shall be dated:

a) A description ofthe meter, giving technical characteristics and principIe of operation. b) A perspective drawing or photograph ofthe meter

e) A list ofparts with a description oftheir constituent material s d) A dimensional drawing

e) A drawing showing locations of seals

f) A drawing of the data plate or badge, showing arrangement of inscriptions g) Instructions for installation, operation, and periodic maintenance

h) A general description of operation

i) A description of available mechanical outputs and electronic output signals, and any adjustment mechanisms

j) A description of available electronic interfaces, wiring points and essential characteristics

k) Documentation of compliance with applicable safety codes and regulations 1) Test report of meter performance

(20)

5. Performance Requirements

5.1 General Performance Tolerances

The manufacturer shall specify flow rate limits for Qmin, Qt and Qmax for each meter design and size. Meter performance at atmospheric pressure sha11 be within the fol1owing tolerances (see a1so Figure 1) after calibration.

Repeatability: ±O.2% from Qmin to Qmax,

Maximum peak-to-peak error: 1.0% aboye Qto

Maximum error: ±1.0% from

Qt

to Qmax, and, ±1.5% from Qmin to Qt,

Transition flow rate:

Qt

not greater than 0.2 Qmax.

Note 1. The tolerances apply after adjustment ofthe change gears (if any) andlor setting ofK-factors and application ofthe fmal meter factor.

Note 2. The tolerances apply after any corrections perfonned within the meter itself but prior to the application of any linearization algorithms by equipment auxiliary to the meter.

Note 3. These tolerances are applicable at atmospheric pressure. As operating gas pressure increases, the perfonnance of the turbine meter can be expected to improve dramatica11y, with sma11er values for repeatability and maximum peak-to-peak error, provided the meter is calibrated for the intended operating conditions.

1.75 1.50 1.25 1.00 0.75

o

0.50

"-ID

0.25

e

0.00 Q)

e

-0.25 ~ -0.50 -0.75 -1.00 -1.25 -1.50 -1.75

f

t====

Repeatabilily +/-0.2%

- Maximum peak-to-peak error

1.0% (a¡ ~ Qt)

f

Qm¡n

al

~ 0.2 Qmax Flow rate (Q¡)

Figure 1. Turbine Meter Tolerances at Atmospheric Pressure

(21)

5.2 Temperature and Gas Composition Influences

The turbine meter shall meet the aboye performance requirements over the full operating range of temperature and gas composition.

5.3 Pressure Influences

Research on the effects of pressure on turbine meter performance was conducted in 2002 and 2003, and the results published in Reference 3. To minimize error, turbine meters should be calibrated for the applicable operating conditions. Guidance on calibration requirements is provided in Section 6.

5.4 Meter Body Interchangeability

Meters with interchangeable measurement cartridges are designed so that the measurement cartridge can be removed from the meter body without removing the body from the installation. This design facilitates in situ inspection and replacement or upgrading of a cartridge.

The construction of a meter with an interchangeable measurement cartridge shaIl be such that the performance characteristics specified in Section 5.1 are maintained after installation of the cartridge in other meter bodies of the same manufacturer, size and model, or after repeated removal and instaIlation of the measurement cartridge in the same meter body. However, slight differences in geometry from the body in which the cartridge was calibrated, body wear, cartridge-body misalignment or other influences may affect the performance of the cartridge and resuIt in measurement error.

An independent study (Reference 4) was conducted to assess measurement error due to cartridge change-out practices. The study indicates that operating a cartridge in a body other than the one in which it was calibrated can introduce random measurement errors from a negligible amount to as much as ±O.35%. Turbine meter users should bear in mind that calibration of measurement cartridges on a stand-alone basis, while convenient and less expensive than calibrating a cartridge and body as a combination, can add to measurement error.

(22)

6. Individual Meter Tests 6.1 Integrity Test

The manufacturer shall test the integrity of a11 pressure-containing components for every turbine meter. The test shall be conducted in compliance with the appropriate industry standard, (ANSIIASME B16.1, B16.5, B16.34 or other, as applicable).

6.2 Leakage Test

Every turbine meter shall be leak-tested by the manufacturer after final assembly and prior to shipment to the customer or flow-calibration facility. The test shall be conducted in compliance with the appropriate industry standard. In the absence of specific standard(s), it is customary for manufacturers to conduct the test as follows: The test medium sha11 be a gas, such as nitrogen or airo The leak-test pressure shall be at least 1.10 times the MAOP and held for a minimum offive minutes. To pass this test, the meter must not have detectable leaks. 6.3 Calibration

In order to establish satisfactory performance characteristics, every turbine meter should be calibrated under conditions acceptable to and agreed upon between the parties to the transaction. For best performance, calibration conditions should match the anticipated in-service conditions, including considerations such as fluid characteristics, operating pressure, expected flow rates, the use of a dedicated meter body, inlet and outlet piping characteristics, and other factors that can affect meter perfonnance. However, limitations on the capability and availability of calibration facilities and the costs associated with transportation and testing may result in decisions to calibrate meters under conditions that, while not identical to those expected in service, provide a reasonable approximation thereof. Attention to replication of the crucial in-service parameters described below will ensure adequate perfonnance for most commercial applications.

6.3.1 Calibra/ion Conditions

Research (Reference 3) has shown that the performance of turbine meter s varíes with changes in flow rate and operating pressure. These variations are related to changes in Reynolds number and, in sorne cases density, and are particularly significant at low and intermediate operating pressures and flow rates. Attention to these issues at the time of calibration is crucial for optimal measurement. The following sections pro vide further guidance in this regard.

6.3.1.1 Reynolds Number

Reynolds number is a dimensionless ratio of inertial to viscous forces in the flow through the meter that takes into account the flow rate and physical properties of a moving fluid. Reynolds number can be used to corre late the calibration and operating conditions of a turbine meter under various flow rates, pressures and fluid types.

(23)

The basic equation for Reynolds number is:

Re = p (D) (V) / JI (6.1)

Reynolds number may also be calculated from either of the following formulae:

where Re = 4(Q) / 1f(D) (0 Re= 4 (Q) (p) !Jr(D) (J.l) Re p(rho) D Reynolds number Density ~eter diameter (6.2) (6.3) V Q

BuIk (average) velocity offlowing fluid Volumetric flow rate

v (nu) J.l (mu)

Kinematic viscosity

= Absolute viscosity

The aboye quantities must all be determined at the same conditions of temperature and pressure.

The relationship between bulk velocity and flow rate is:

(6.4) The relationship between absolute and kinematic viscosity and density is:

(6.5)

A meter calibration carried out in a test facility over a particular range of Reynolds numbers characterizes the meter' s performance when used to measure gas over the same range of Reynolds numbers when the meter is in service. Therefore, the K-factors established during such a calibration, in most instances, can be used to compute flow measured by the meter in service.

6.3.1.2 Densíty

Research (Reference 3) has shown that the performance of sorne meters may al so be sensitive to variations in gas density. Variations in calibration tend to be larger at lower gas densities. Users with low-pressure, low-flow applications should consult the meter manufacturer for meter performance characteristics and obtain calibration data at the operating density to ensure that no significant measurement errors exist. Additional information on density matching is provided in Appendix E.

6.3.1.3 Calibratían Gases

The research described in Reference 3 was conducted using natural gas and air as test media. In addition, Reference 6 describes research that has been conducted to establish the suitability of other gases for calibration of turbine meters. The data show that turbine meters used in natural gas can be effectively calibrated in different

(24)

gases, and that satisfactory measurement will result provided calibration is conducted over the range of Reynolds numbers ami/or density expected at operating conditions. Further information on calibration in altemative gases is provided in Appendix E.

6.3.2 Calibration Guidelines

As discussed aboye, the expected operating Reynolds number range ami/or density for a meter needs to be taken into account when designing a calibration programo This requires establishing the expected range of flow rates and the properties of the gas to be measured at the intended meter location. The gas properties may be determined directly by measurement or by calculation from empirical equations.

Test points should be selected throughout the range offlow rates over which the meter is to be tested. It may be decided to concentrate the majority of the test points in the range ofthe meter's heaviest expected usage.

Further information and sample calculations appear in Appendix E.

6.3.3 Calibration Configuration

To minimize errors, meters should be calibrated in the same configuration as intended to be installed in service. However, most test facilities routinely perform calibrations in the recommended configuration described in Section 7.2. Research (Reference 2) has shown that the errors of meters calibrated in this manner will be acceptable when installed in any of the configurations described in Section 7.2. For applications with more severe installation configurations, the user should consult the manufacturer or test facility operator for experimental data to determine an adequate calibration configuration.

6.3.4 Calibration Facilities

Test facilities used for meter calibration shall be able to demonstrate traceability to relevant national primary standards and provide test results that are comparable to those from other such facilities.

6.3.5 Calibration Results

During calibration, the appropriate K-factor(s), meter factors, change gears ratios and rotor factors will be established. The applicable factors will be established for each output for meters with more than one output. Refer to Appendix D for detailed information and examples of determining and applying these factors.

6.3.5.1 Change Gears

For turbine meters with mechanical output(s), intemal gearing is typically used to adjust the registration to produce a (nearIy) fmite indicated volume (e.g., 100 cubic feet, 10 cubic meters, etc.) for each revolution of the output shaft. Differing change gear sets, comprised of two replaceable mating gears incorporated within the gear train, perrnit adjustments to be made to the overall gear ratio. While change gear sets with many ratios are available, it is not always possible to install gears with the precise ratio needed. Thus, there may be sorne residual bias in the meter's calibration

(25)

even after the best available change gears have been installed. The change gears are usualIy located in a non-pressurized region of the meter that is accessible during calibration, but that can be sealed to prevent unauthorized access. When an interchangeable measurement cartridge is moved to a new body, the change gears shalI be moved also.

6.3.5.2 K-Factor(s)

For turbine meters with electronic output(s), the appropriate K-factor(s) is established at the time of calibration. These value(s) are then entered into an electronic accessory device. The K-factor(s) is expressed in units of pulses/unit volume. By dividing the accumulated pulses by the K-factor or by dividing the instantaneous pulse frequency by the K-factor, the accumulated volume or the instantaneous flow rate, respectively, can be determined.

6.3.5.3 Meter Factors and Final Meter Factor

Meter factors are non-dimensional multiplier values. They are derived from calibration data by dividing the true volume of the reference meter by the indicated volume of the test meter, both volumes having first been corrected to the same base conditions. Alternatively, meter factors can be calculated from the percent error values provided at each calibration flow rate, by the formula:

M eter factor = 100 / (1 00 + percent error)

Thus, the meter factor example of 1.005 would be the same as -0.5 percent error. The mechanical or electronic outputs of a turbine meter may be adjusted by the application of individual meter factors for specific flow rates or by a single final meter factor over the range of flow rates. This may be done omine manualIy or online in an electronic accessory device. The calibration facility may provide meter factors in addition to or in place of percent error values for each test flow rate of a meter.

6.3.5.4 Rotor Factorsfor Dual-Rotor Meters

For dual-rotor turbine meters, with associated algorithms for enhanced performance and diagnostics, the manufacturer will supply unique K -factors for each rotor' s electronic pulse output. These are referred to as "rotor factors" to distinguish them from K-factor, which is the term historically used to apply to the single-rotor electronic output of a meter. Refer to Appendix A, Sections A.2 and A.3 and to Appendix D, Section D.5 for more details.

6.3.5.5 Meter Verification Test

Following an adjustment, at least one test point shall be repeated to verify that the adjustment was calculated and applied correctly. If a linearization technique is applied in secondary or companion electronics, then at least two test points shalI be repeated.

(26)

6.4 Test Reports

The resuIts of each test required in Section 6.3 shall be documented in a report including, as a mmlmum:

a) The name and address of the manufacturer b) The name and address of the test facility c) The model, size and serial number of the meter d) The date(s) ofthe test

e) The name and title of the person who conducted the tests f) The meter performance data

g) Test pressure and temperature

h) Ambient temperature and atmospheric pressure

i) Test fluid, composition and properties at each test point, ifvarying j) A description of the test configuration used

k) The value of any adjustment made and the results of the verification test

A copy of the report shall be available from the testing organization for a period of five years. 6.5 Quality Assurance

The manufacturer shall establish and follow a comprehensive quality-assurance program for the assembly and testing of the meter and its electronic system (e.g., ISO 9000, API Specification Q 1, etc.). The user shall have access to the quality-assurance documents and records.

(27)

7. Installation Specifications

The impact on measurement has been assessed for the configurations described below. Various organizations have published test data. Configurations other than those described below may result in unacceptable measurement errors and are not recommended without further testing.

7.1 General Considerations

7.1.1 Flow Direction

Turbine meters, designed for flow in one direction only, shall be installed accordingly. Reverse flow may not damage the meter internals but may result in registration error. Tbe manufacturer may be consulted if reverse flow has occurred. Where reverse flow is expected, additional valving is necessary to allow gas to flow through the meter in the forward direction only, unless the turbine meter is recommended for bi-directional flow.

7.1.2 Meter Orientation and Support

Turbine meters, designed for horizontal orientation, shal1 be installed accordingly. A vertical in-line installation may be used; however, the manufacturer's recommendations for piping configuration and maintenance should be fol1owed. The meter and meter piping shall be adequately supported and installed so as to rninimize strain on the meter body.

7.1.3 Meter Run Connections

The meter and adjacent pipe sections should have the same nominal diameter, but schedule changes are acceptable provided satisfactory meter performance has been demonstrated. Meter inlet and outlet connections and companion pipe flanges shall be aligned concentrically. Gaskets shall not protrude into the flowing gas stream. Gasket protrusion or flange misalignment can affect meter perfonnance.

7.1.4 Internal Surfaces

The intemal surface of the meter should be kept cIear of any deposits that may affect the meter's sectional area. The meter's perfonnance depends on a known cross-sectional area. Pipe interior surfaces should be of commercial roughness or better. Welds on piping at the meter inlet and outlet should be ground flush with the internal surface of the pipe so that they do not protrude into the gas stream.

7.1.5 Temperature Well Location

The temperature well shall be located downstream of the meter to keep disturbances to a minimum. Generally temperature wells are installed between one and five nominal pipe diameters from the meter outlet but upstream from any valve or flow restrictor. It is important that the temperature well be installed to ensure that heat transfer from the adjacent piping and radiation effects of the sun do not influence the temperature reading of the flowing gas.

(28)

7.1.6 Pressure Tap Location

The pressure tap provided by the manufacturer on the meter shall be used as the point of pressure sensing for recording or integrating instruments and during calibration.

7.1. 7 Flow Conditioning

A flow conditioner may be used upstream of the turbine meter to reduce or eliminate the effects of swirl amI/or asymmetric flow. Headers, pipefittings, valves and regulators preceding the meter inlet may cause perturbed flow conditions. Flow conditioners shall be installed as specified in the following sections. There shall be no protrusions into the piping between the flow conditioner and the meter.

7.1.7.1 Tube Bundle Type Straightening Vanes

For specifications for these devices, refer to the latest revision of AGA Report No. 3,

Orifice Metering

01

Natural Gas and Other Related Hydrocarbon Fluids (Reference

10). This design has demonstrated its effectiveness in the reduction of swirl but does not eliminate asymmetric flow.

7.1.7.2 Other External Flow Conditioners

Isolating flow conditioners offer an alternative to tube bundles. They are recom-mended for use if the contracting parties agree. Isolating flow conditioners general1y consist of perforated plates in various parterns, sometimes accompanied by vane assemblies. Several of these devices have been evaluated for performance and found to be effective in reducing swirl and asymrnetric flow.

7.1.7.3 1ntegral Flow Conditíoners

Only meters incorporating integral flow conditioners as described in Section 7.2.2.3 are recornmended for use in the short and close-coupled installations described in Sections 7.2.2.1 and 7.2.2.2.

7.2 Recornrnended Installation Configurations

Research (Reference 2) shows that turbine meters may be operated according to the recornmendations in this section with acceptable results, while more severe piping arrangements may result in considerable error. The magnitude of the error, if any, will be a function of the extent of the flow disturbances, the meter' s design, the quality of external and integral flow conditioning, amI/or the meter's ability to adjust for such conditions. However, other configurations may be used provided they are shown to be acceptable based on published experimental data.

(29)

7.2.1 Recommended Installationfor In-Line Meters

The recommended installation (Figure 2) ineludes at least 10 nominal pipe diameters of straight pipe upstream of the meter inlet, with a flow conditioner oudet located 5 nominal pipe diameters upstream of the meter inlet.

Turbine Meter Pressure Tap

r'o "",."', """

0""' ....

--1

'-, l, 1

c=

,:='

=-==~:=J

----,

,

L. Optional _______ ---l - 19 Tube Bundle

- or Flow Conditioning Element

I

5 Nominal Pipe [1)[2)

I

r-

Diameters

1

Temperature Well

Optional

- Rel. Temperature Well - Sample Probe

Recommended - Blow Down Valve [3]

.,J

7 _ Optional

\f.ii -

Flow Limiting

¡ '. ¡¡

I

Device

.!-\

':'f[J'-r-~--~~~~

,

, ,

_,

r---~,

:

L. Minimum

~

5 Nominal Pipe Diameters

NOTES: [1] Recommended spacing, unless otherwise supported by published test data lor the fiow conditioning elemen!. [2] No pipe connections or protrusions allowed within this upstream section.

[3] For recommended size 01 blow down valve, see Table 1. Locate downstream 01 meter.

Figure 2. Recommended Installation Configuration for In-line meters

A minimum length of 5 nominal pipe diameters of straight pipe is inc1uded downstream of the meter. There shaIl be no pipe connections or protrusions within the upstream or downstream piping other than pressure taps, temperature wells or flow-conditioning elements.

A typical recornmended installation meter run with accessories and optional devices is shown in Figure 3. The maximum pipe-size difference upstream or downstream of the recornmended installation should be one nominal pipe size. Valves, filters or strainers may be instaIled upstream or downstream of the recommended instaIlation piping. Any valve immediately upstream of the installation shall be fuIly open during meter operation. Strainers and filters should be kept c1ean for optimum performance.

(30)

Turbine Optional

Optional - Ref. Temperature Well

- Filter - Sample Probe

Optional - Flow limiting Device

90· Elbow or Tee - or Strainer Pressure

1

Recommended

Maximum Tap ~e~perature

l

-

Blow Down

Reduction 10 Nominal Pipe 1 -5

r

":.: .... :'

j

V~~~!~)stream

: [ : - - - - : OH

~"~"~

_ _ DO.

_c·_

:10;J':lJ--"'-M~¡[):

1 1 1 1 l ' J 1

Lo

r - ~L - - ~

Lol..lj

- Lo •

t-_-..,.

5 Nominal _

I

l.

Minimum ~

I

~~~"j :: Pipe[1][2] - ,

¡+-

5 N~;:nal

I

~¡"";':' .... "j ~,. ~"'~\ ., Diameters D i a m e t e r s " " ~"'~\ Optional:,."'tl \)1 ~" :,."',,( \)1 Optlonal

-Valve,'v '~I ~rlo Realmmended - Optional Optional

,'v

'~I -Valve

~::: ::::.... .~ Pressure-Ioading -19 Tube Bundle [ . _ Bypass Une _ ~ ::: :::: ....

L?2~::~-~-J =~::/~D E~:'::"~COnd-

_/_~ _psigl31 _{-1 ",,_} _{- •}

"""V....

~ ~

I

.7 - - -

-l

f~(->'

'.

lo -

---_:

_{~I ~::::}

~~~~~

...

L ---

1

NOTES: [1) Recommended spacing, unless olherwise supported by published test data lor the flow conditioning element. [2) No pipe connections or protrusions allowed within this upstream section.

[3) Size 01 pressure loading line and valve to be the same as recommended blow down valve sizing, (see Table 1).

Figure 3. Typical Meter Set Assembly: Recommended Installation

7.2.2 Optionallnstallation Configurations for In-Line Meters

The use of the following optional installation configurations may result m relatively higher, but still acceptable, measurement uncertainty.

7.2.2.1 Short-Coupled Installation

The short-coupled installation configuration shown in Figure 4 may be used where space is limited. Initial limited research (Reference 2) on tested meters indicates that locating a short-coupled installation with meter-integrated flow conditioning downstream of a high-Ieve1 perturbation (as defined in Reference 7) caused measurement bias not exceeding ±O.4% ofreading, which was within the error limits of ±1.0% specified in Section 5.1 (Figure 1). See Section 7.2.2.3 for a discussion on meter-integrated flow conditioning and Section 6.3 for calibration requirements. The short-coupled configuration includes at least four nominal pipe diameters of straight pipe upstream of the meter inlet, with a flow conditioner located at the inlet of the straight pipe. In addition, the distance between the flow conditioner outlet and the meter inlet should be at least two nominal pipe diameters.

The meter may be connected to the vertical risers using elbows or tees. Tees enable visual inspection of the meter runo The maximum difference in size between the mn and the risers shall be one nominal pipe size. The installation of optional valves, filters or strainers in the risers is permitted, although users are cautioned that inclusions in the risers have not been confirmed by published research. Any valve in

(31)

the inlet riser shall be fully open during meter operation, and strainers and filters should be kept c1ean for optimum performance.

Optional 90 o Elbow or Tee _ Filler

Maximum Reduction _ or Strainer Pressure Tap

OM~:m~"",

p.,

S"

l i

, 1'---

C!-==J

' I , I

,1'

~ , I '- - F

J.

.. 1..' Inlet,L--' Minimum 2 Nominal [1) [2) _.:~ Pipe Diameters , - - - " Optional - : ~.: ~" I

=-

_

19 Tube Bundle Optional 1 :,14..

11 (~~I'. ~ ~', - or Flow Conditioning Element - Valve 1 \\ ... ~ "1 L~~

\ ... -"1

=.

"-I

9~~

Recommended Pressure-Ioading Une and valve lor operation over 200 psig [3) Turbine Meter [4) r,~ ---, i ' , i ' , i , _..J i ' .. L.' ::::::::C~:f::] c.A ::! OPtiona~--1 - : "j

t

- Flow Limiting , ~.: ~ ~~ Device ':' lc< \ 11 Recommended 1 \ .... _{\\~_'"}

"1

-BlowDown ~ ".-,: ... J Valve [3) Optional ,-"- -, -V . . . -~

NOTES; [1) Recomrnended spacing, unless otherwise supported by published test data lor the flow conditioning elemen!. [2) No pipe cooneclions or prolrusions allowed wilhin this upstream section.

[3) Size 01 pressure loading line and valve lo be the same as recommended blow down valve sizing, (Table 1). [4) Turbine meler musl have integral flow conditioner.

Figure 4. Short-Coupled Installation

7.2.2.2 Close-Coupled Installation

The close-coupled installation configuration shown in Figure 5 may be used where space is severely limited. Just as in the case of short-coupled installation, initial limited research (Reference 2) on tested meters also indicates that locating a close-coupled installation with meter-integrated flow conditioning downstream of a high-level perturbation (as defined in Reference 7) caused measurement bias not exceeding ±O.4% of reading, which was within the error limits of ± 1.0% specified in Section 5.1 (Figure 1). See Section 7.2.2.3 for a discussion on meter-integrated flow conditioning and Section 6.3 for calibration requirements.

Ihe meter may be connected to the vertical risers using elbows or tees. Iees enable visual inspection of the meter runo The maximum difference in size between the mn and the risers shall be one nominal pipe size. Ihe installation of optional valves, filters or strainers in the risers is permitted, although users are cautioned that inclusions in the risers have not been confmned by published research. Any valve in the inlet riser shall be fully open during meter operation, and strainers and filters should be kept c1ean for optimum performance.

(32)

Pressure Tap

Turbine Meter (1) 90 o Elbow or Tee

Maximum Reduction One Nominal Pipe Size

I-rl 1 I 1 -1 I 1 1 I1 1 I 1 __ ... LI

f'-=1.

--11 ... ,...-...-rl ..!..

.~---"

'1'\ "/ ,'~ J\H Optional

II~ 1" r~ I)I~ -Valves

r.. ~~ '~~( _

>.,'//

1 ... ,::: .. - ... 1

Recommended ~I ~ _ _ _ ~ Pressure-Ioading

!!.-_-

1 1

line and valve for~ 90 o Elbow operatlon over 200 psig [2)

'-1-

1 - - - ¡ 1 , , I 1 , I 1 Recommended

- -1 I 1

¡ _

Blow Down Valve ... ,.~ l. (Downstream) [2)

~

:. -..::_

;~\.':::{;J~}'

.~_-""''1 a_ ... ,'~ J\\\ ...,..," ~ 1)1 ,,,( .. " ' Optional

.. ' .. -:,.>, .... ( -Flow Limiting Device

r~' ... c..l ..

L\S

NOTES: [1) Turbine meter must have integral flow condilioning elemenl.

[2) Size of pressure-Ioading line and valve to be the same as recommended blow down valve sizing, (Table 1).

Figure 5. Close-Coupled Installation

7.2.2.3 Meter-Integrated Flow Conditioning

Research (Reference 2) has confirrned that turbine meters with integral flow conditioning in the nose-cone flow passages operate satisfactorily in short and close-coupled installations. Those integral flow conditioners tested were similar in design to that shown in Figure 6 and to those evaluated in Reference 8. For this design, the aspect ratios are BID < 0.15 and SIL < 0.35. These parameters are illustrated in Figure 6.

Integral Flow Conditioning on Nose-cone

D

H - radial height of annular flow passage D - d iameter of the meter ¡nlet.

1--

L

_"'1

s -

maximum chordlength between vanes L - vane len gth in axial direction

(33)

7.2.3 Suggested Installation for Angle-Body Meters

A suggested installation for angle-body meters is shown in Figure 7, When a flow conditioner is not used, 10 nominal pipe diameters of straight pipe shall be provided upstream of the meter. When a flow conditioner is used, the flow conditioner inlet shall be a minimum of five nominal pipe diameters from the meter inlet and the length of straight upstream pipe may be reduced to 5 diameters.

90 o Elbow or Tee Maximum Reduction One Nominal Pipe Size

Horizontal Installation (Inlet in Horizontal Plane, Outlet Down )

Oplional - Filler

- or Slrainer Pressure Tap

\ r-

Inlel Piping 10 Nominal Pipe Diamelers Long

-1

(5 Nominal Pipe Diamelers wilh 19 lube bundle)

(1)[2) Angle-Body Turbine Meler

,-

-¡

!!~~~~~~"J r--

o

,--- -;-;í

--

....

,-

" J~; .... " II ,A. ' \ " ~ Oplional '" tC<

'p

~¡¡ - Valve

1",· __ "

~ ~ \'.... _"-,..:-_...

"',

,,

,... _,~ ,...1 ... , "

::)1:,-"

90 0

"0

:~

Oplional - 19 Tube Bundle

- or Flow Conditioning Elemenl

Recommended Pressure-Ioading line and valve for operalion over 200 psig (3)

. - . 1 - - - - 1

Recommended ~~~,

J

- Blow Down Valve I } ,

¡:::::

Temperalure Well Downslream [3) / ' , _ _ _ , -)--;'':.~Q ,',..-'\\\ Optional '" rC< ')' Optional - Flow Lim~ing "" ' .... , , - Valve

Device \ ... ..:-::,

I ' . . . . ,

-~

NOTES: [1) Recommended spacing, unless olherwise supported by pubfished lesl dala lor Ihe f10w conditioning elemenl. [2] No pipe connections or prolrusions allowed within Ihis upslream section.

[3] Size of pressure loading fine and valve lo be Ihe same as recommended blow down valve sizing, (see Table 1).

Figure 7, Suggested Installation for Angle-Body Meters

The meter inlet piping may be connected using a 90° elbow or tee, There are no restrictions on the downstream piping except that the flange attached to the meter outlet shall be full-size. Any valve immediately upstream ofthe installation shall be open fully during meter operation.

The installation may be oriented vertically,

Caution: Users are cautioned that the error of the angle-body configuration has not been confinned by published research. Contact the manufacturer for supporting experimental data for specific installation requirements,

(34)

7.3 Environmental Considerations

7.3.1 Temperature

The meter shall be installed and used within the ambient and flowing gas temperature limits specified by the manufacturero

7.3.2 Vibration

Turbine meters are in general not susceptible to vibration. However, vibration frequencies should be avoided that might excite the natural frequencies of the piping set, potential1y leading to excessive noise, structural damage to the pipe, amI/or reduced bearing service life of the meter.

7.3.3 Pulsations

Pulsations may occur in several forms depending on the design of the system and the operating conditions. Turbine meters installed near compressors and fast-cycling regulators can register incorrectly. Flow pulsations generated by this type of equipment will generally cause a turbine meter to over-register. Pulsation dampeners installed between the source of pulsation and the turbine meter are an effective way of eliminating pulsation-induced measurement errors. Flow transients experienced in normal operation have negligible effect on turbine meter performance because turbine meters in general have the ability to follow slow changes in flow rate.

7.3.4 Hydrate Formation and Liquid Slugs

Slugs of liquid or solids entering the meter may damage the meter. The presence of hydrates in the meter installation will cause inaccurate measurement. The meter piping should be designed to prevent liquid accumulation in the meter body and meter runo 7.4 Associated Devices

7.4.1 Filtration and Strainers

Filtration of the flowing gas may not be necessary in all cases but is recornmended for most meter applications. The accumulation of deposits due to a mixture of dirt, milI scale, condensates and/or lubricating oils will deteriorate meter performance. Bearing wear and measurement cartridge damage aml/or failure can be caused by foreign material in the flowing stream. Normal pipeline gas quality may deteriorate during peak demands, plant upsets and new tie-ins, or from normal internal pipeline corrosion resulting in dust, dirt andJor scale. Under such conditions, it is recornmended that a strainer with a basket of 3/32 inch maximum hole size and 40 mesh wire liners be installed upstream of the meter to catch the major part of this foreign material. In sorne instances, it may be preferable to install lO-micron filters for the removal of fine dust, thus increasing bearing life and minimizing deposits on the meters internal parts. A differential pressure gauge should be installed across the filter or strainer to indicate an increase in pressure drop resulting from a build-up of foreign matter in the filter or strainer. Normal pressure drop should be observed and recorded at various flow rates when the strainer or filter is clean.

(35)

Inspection of the devices should be performed whenever higher than normal pressure drops are indicated on the differential pressure gauge.

A greater degree of meter protection can be accomplished through the use of a dry-type or separator-type filter installed upstream ofthe meter inlet piping.

When cornmissioning a pipeline, it is recornmended that the meter be bypassed or a temporary strainer element installed to protect the meter from dirt and debris entrained within the initial flow.

7.4.2 Throttling Devices

The installation of a throttling device, such as a regulator or partially closed valve, is not recornmended in close proximity, especially upstream, to the meter. Where such installations are necessary, the throttling device should be placed an additional eight nominal pipe diameters upstream or an additional two nominal pipe diameters downstream of the in-line recornmended installation in Figure 2. In the configurations illustrated in Figures 3, 4, 5 and 7, the throttling device should be placedeight additional nominal pipe diameters upstream of the inlet vertical riser or an additional two nominal pipe diameters downstream of the oudet vertical riser. Placement of such a device in c10ser proximity to the meter may result in increased uncertainty amI/or reduced bearing life.

7.5 Precautionary Measures

7.5.1 Installation Residue

To prevent possible damage, the measurement cartridge or meter should be removed if work such as welding, hydrostatic testing, etc., is being performed in the irnmediate area of the meter. The inside of the meter body and piping shall be thoroughly c1eaned and inspected for construction debris prior to replacement.

7.5.2 Va/ve Grease

Grease can flow from sorne pipeline val ves into the gas stream during lubrication. Val ve grease can adhere to turbine meter blades, thereby affecting meter performance. Such valve types should not be located irnmediately upstream of a turbine meter.

7.5.3 Over-Range Effects

Surges of high-velocity gas through a turbine meter can severely damage the rotor. Extreme gas velocities can occur when pressurizing, blowing down or purging the meter runo The operation of flow- or pressure-control devices in the downstream piping system can also create extreme gas velocities.

7.5.3.1 Run Pressurization

It is good practice to provide isolation block valves for meter runs so that the meter(s) can be maintained and calibrated without service interruptions. F or single meter run stations, a flow bypass line should also be considered (see Figure 3). The isolatÍon block valves must be operated in the proper sequence and slowly to avoid reverse