ASME MFC-16 pdf free download
ASME MFC-16 pdf free download Measurement of Liquid Flow in Closed Conduits With Electromagnetic Flowmeters
1sCOPE
This Standard is applicable to industrial electromag-netic flowmeters and their application in the measure-ment of liquid flow.The electromagnetic flowmeterscovered by this Standard utilize an alternating electricalcurrent (AC) or pulsed direct-current (pulsed-DC) togenerate a magnetic field in electrically conductive andelectrically-homogeneous liquids or slurries flowing ina completely filled, closed conduit.
This Standard specifically does not cover insertion-type electromagnetic flowmeters,meters used to mea-sure flow in partially filled pipe, or those used in surgi-cal,therapeutic,”or other health and medicalapplications. It also does not cover applications of indus-trial flowmeters involving nonconductive liquids orhighly conductive liquids (e.g-, liquid metals).
REFERENCES
All references are to the latest published edition ofthese standards. The following is a list of publicationsreferenced in this Standard.
ASME B16 Series, Standards for Valves, Fittings,Flanges, and Gaskets
ASME MFC-1M,Glossary of Terms Used in theMeasurement of Fluid Flow in Pipes
Publisher: The American Society of MechanicalEngineers (ASME)，Three Park Avenue,New York,NY10016-5990; Order Department: 22 Law Drive,PO. Box 2300,Fairfield, NJ07007-2300
ISO 13359,Measurement of Conductive Liquid Flow inClosed Conduits — Flanged ElectromagneticFlowmeters —Overall Length
Publisher: International Organization for Standardiza-tion (ISO),1, ch. de la Voie-Creuse, Case postale 56,CH-1211, Geneve 20,Switzerland /Suisse
3DEFINITIONS AND SYMBOLS
(a) Paragraph 3.1 lists definitions from ASMEMFC-1M used in ASME MFC-16.
(b) Paragraph 3.2 lists definitions specific to thisStandard.
(cy Paragraph 3.3 lists symbols used in this Standard(see ‘Table 1).
3.1 Definitions From ASME MFC-1M
accuracy: the degree of freedom from error; the degreeof conformity of the indicated value to the true valueof the measured quantity.
precisionr: the closeness of agreement between the resultsobtained by applying the experimental procedure sev-eral times under prescribed conditions.The smaller therandom part of the experimental errors that affect theresults, the more precise is the procedure.
rangeabilify (furndocvn): flowmeter rangeability is theratio of the maximum to minimum flow rates or Reyn-olds number in the range over which the meter meetsa specified uncertainty (accuracy).
repeatability: the closeness of agreement among a seriesof results obtained with the same method on identicaltest material, under the same conditions (same operator,same apparatus, same laboratory, and short intervals oftime).
ncertainty (of mieasremernt): the range within which thetrue value of the measured quantity can be expected tolie with a specified probability and confidence level.3.2 Definitions for ASME MFC-16
bias: the systematic errors (i.e., those that cannot bereduced by increasing the number of measurementstaken under fixed flow conditions).
flowwmefer prinary: includes the flowtube, process connec-tions, electromagnetic coils, and electrodes. Flowmeterprimary is also known by other names such as: flow-meter primary device, primary device, primary etc.flowmeter secondary: includes the electronic transmitter,measurement of the enf, and in most cases the powerfor the electromagnet coils of the flowmeter primary.liniearity: linearity refers to the constancy of the meterfactor over a specified range, defined by either the pipeReynolds number or the flow rate.
ieter factor: the number, determined by liquid calibra-tion, that enables the output flow signal to be relatedto the volumetric flow rate under defined reference con-ditions.
3.3 SymbolsSee Table 1.
4 THEORY AND MEASUREMENT TECHNIQUE A partial sketch of an industrial electromagnetic flow- meter is shown in Fig. 1. Figure 2 shows a typical installationofthe electromag- netic flowmeter.
4.1 Flow-Related Electromotive Force Faraday’s Law of Induction applied to this physical configuration predicts the generation of an electromo- tive force (a voltage) between the electrodes when a conductive liquid flows through the flowtube. This elec- tromotive force is
4.2 Electrochemical Electromotive Force In addition to the flow-related electromotive force, emf v , an electrochemical electromotive force, emf c , is present between the electrodes. The emf c is an electro- chemical emfproduced in the flowmeter primary similar to that generated in a battery. It can be similar in magni- tude to emf v and changes slowly. In order to reduce emf c , which would be a measurement bias, an alternating electromagnetic field is used. There exist a number of variations of the basic AC and DC fields shown in this Standard. See para. A-2.1 for additional information. This electrochemical voltage, which varies slowly in time, is substantially reduced in magnitude by utilizing an alternating electromagnetic field.
