ASME MFC-16:2007 pdf download

ASME MFC-16:2007 pdf download.Measurement of Liquid Flow inClosed Conduits with Electromagnetic Flowmeters.
This Standard is applicable to industrial electromagnetic flowmeters and their application in the measurement of liquid flow. The electromagnetic flowmelers cxnrered by this Standard utilize an alternating electrical current (AC) or pulsed direct-current (pulsed-DC) to generate a magnetic field in electrically conductive and electrically-homogeneous liquids or slurries flowing in a completely filled, closed conduit.
This Standard specifically does not cover insertion- type electromagnetic flowmeters, meters used to measure flow in partially filled pipe, or those used in surgical, therapeutic, or other health and medical applications. It also does not cover applications of industrial flowmeters involving nonconductive liquids or highly conductive liquids (e.g., liquid metals).
2 REFERENCES
All relerences are to the latest published edition of these standards. The following is a list of publications referenced in this Standard.
ASME B16 Series, Standards for Valves, Fittings, Flanges, and Gaskets
ASME MFC-IM, Glossary of Terms Used in the Measurement of Fluid Flow in Pipes
Publisher: The American Society of Mechanical Engineers (ASME), Three Park Avenue, New York, NY 10016-5990; Order Department: 22 Law Drive, P.O. Box 2300, Fairfield, NJ 07007-2300
ISO 13359, Measurement of Conductive Liquid Flow in Closed Conduits — Flanged Electromagnetic Flowmeters — Overall Length
Publisher: International Organization for Standardization (ISO), 1, ch. de Ia Voie-Creuse, Case postale 56, CH-121 1, Genève 20, Switzerland/Suisse
3 DEFiNITIONS AND SYMBOLS
(a) Paragraph 3.1 lists definitions from ASME MFC-1M used in ASME MFC-16.
(b) Paragraph 3.2 lists definitions specific to this Standard.
(C) Paragraph 3.3 lists symbols used in this Standard (see Table 1).
4.2 Electrochemical Electromotive Force
In addition to the flow-related electromotive force, enlfr,, an electrochemical electromotive force, emf, is present between the electrodes. The cmj is an electrochemical emfprodui:ed in the flowmeter primary similar to that generated in a battery. It can be similar in magnihide to ernf and changes slowly. In order to reduce ernf, 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.
The manner in which the electromagnetic field is varied includes the following:
(a) AC — field is varied in a sinusoidal fashion Esee Fig. 3, illustration (a)I
(b) DC — field is varied in a stepwise fashion Isee Fig. 3, illustrations (b) and (c)I
4.3 Types of Electrodes
An alternating electromagnetic field generates an alternating t”mf1,. Two types of electrodes can be used with an alternating electromagnetic field
(a) wetted electrodes that protrude through the pipe wall/liner into the flow stream [see Fig. 4, illustration (a)J
(b) nonwetted (capacitive) electrodes located behind or within the tube wall/liner Isee Fig. 4, illustration (b)j
4.4 CalculatIon of Volumetric Flow Rate
From eq. (1) the flow velocity is given by.