ASME MFC-3M:2004 pdf download Measurement of Fluid Flow in Pipes Using Orifice, Nozzle, and Venturi
1-1 SCOPE AND APPLICATION
This Standard specifies the geometry and method ofuse (installation and operating conditions) for pressuredifferential devices (including, but not limited to, orificeplates, flow nozzles, and venturi tubes) when installedin a closed conduit running full and used to determinethe flow-rate of the fluid flowing in the conduit. ThisStandard applies to pressure differential devices inwhich the flow remains subsonic throughout the meas-uring section and where the fluid is considered assingle-phase.The Standard is limited to single-phaseVewtonian fluid flow in which the flow can be consid!ered sufficiently free from pulsation effects. It gives in-formation for calculating the flow-rate and the associateduncertainty when each of these devices is used withinspecified limits of pipe size and Reynolds numberThis Standard covers flow meters that operate on theprinciple of a local change in flow velocity and/or flowparameters caused by meter geometry, resulting in acorresponding change of pressure between two set lo-cations. Although there are several types of differentialpressure meters available, it is the purpose of this Standard to address the applications of each meter and notto endorse any specific meter. The operating principleof a pressure differential flow meter is based on twophysical laws: conservation of energv and conservationof mass, realized when changes in flow cross-sectionalarea and/or flow path result in a change of pressure.This differential pressure, in turn, is a function of theflow velocity, fluid path, and fluid properties.Included within the scope of this Standard are devicesfor which direct calibration experiments have beenmade, sufficient in number and data coverage, to enablevalid systems of application to be based on their resultsand coefficients to be given with known uncertainties.The devices installed in the pipe are referred to as primary devices ，primary elements , or simply, primaries. Theprimary device may also include the associated upstreamand downstream piping. The other instruments requiredfor the flow measurement are often referred to assecondary devices or secondaries. For further information onsecondary instrumentation, see ASME/ANSIMFC-8MThe different primary elements covered in this Stan-dard are as follows:
(a) orifice plates (Part 2) that can be used with the fol-lowing pressure tap arrangements:(1) flange pressure taps(2) corner pressure taps(3) D and D/2 pressure taps(b) nozzles (Part 3), each of which differs in the fol-lowing shape and position of the pressure taps:(1) ASME long radius nozzles(2) Venturi nozzles(3) ISA 1932 nozzles(c) ASME venturi tubes (Part 4), also known as Herschel or classical venturi tubesPart 1 of this Standard contains general material suchas definitions, symbols, and principles that apply to all thedevices covered in Parts 2, 3, and 4 of this Standard withrespect to the flow measurement of any single phase fluidThis Standard does not apply to ASME PerformanceTest Code measurements. This Standard does not ad-dress those devices that operate on the principle of critical or choked flow condition of fluids. This Standarddoes not address issues of safety. It is the responsibilityof the user to ensure that all systems conform to appli-cable safety requirements and regulations.
1-2REFERENCES AND RELATED DOCUMENTS
Unless indicated otherwise, the latest issue of a refer-ence standard shall be used.ASME B36.10, Welded and Seamless Wrought Steel PipeASME MFC-1M, Glossary of Terms Used in the Mea-surement of Fluid Flow in PipesASME MFC-2M, Measurement of Uncertainty for FluidFlow in Closed ConduitsASME MFC-8M,Fluid Flow in Closed Conduits-Con-nections for Pressure Signal Transmission BetweenPrimary and Secondary Devices
ASME PTC 6Steam TurbinesASME PTC 19.5,Flow MeasurementPublisher: The American Society of Mechanical Engineers (ASME), Three Park Avenue, New York, NY10016-5990;Order Department:22 Law Drive, Box2300,FairfieldNT 07007-2300