ASME MFC-16:2007 pdf free download

ASME MFC-16:2007 pdf free download.Measurement of Liquid Flow in Closed Conduits with
Electromagnetic Flowmeters.
3.1 Definitions From ASME MFC-1M
accuracy: the degree of freedom from error; the degree of conformity of the indicated value to the true value of the measured quantity
precision: the closeness of agreement between the results obtained by applying the experimental procedure several times under prescribed conditions. The smaller the random part of the experimental errors that affect the results, the more precise is the procedure.
rangeahility tu rudown: flowmeter rangeabi Ii ty is the ratio of the maximum to minimum flow rates or Reynolds number in the range over which the meter meets a specified uncertainty (accuracy).
repeatability: the closeness of agreement among a series of resulLs obtained with the same method on identical test material, under the same conditions (same operator, same apparatus, same lahoratory and short intervals of time).
uncertainty (of measurement): the range within which the true value of the measured quantity can be expected to lie with a specified probability and confidence level.
3.2 Definitions for ASME MFC16
bias: the systematic errors (i.e., those that cannot be reduced by increasing the number of measurements taken under fixed flow conditions).
flowmeterprin:ary: includes the flowtube, process connections, electromagnetic coils, and electrodes. Flowmeter primary is also known by other names such as: flow- meter primary device, primary device, primary etc.
includes the electronic transmitter, measurement of the crnf,, and in most cases the power for the electromagnet coils of the flowmeter primary.
linearity: linearity refers to the constancy of the meter factor over a specified range, defined by either the pipe Reynolds number or the flow rate.
meter factor: the number, determined by liquid calibration, that enables the output flow signal to be related to the volumetric flow rate under defined reference conditions.
3.3 Symbols See Table 1.
4.2Electrochemical Electromotive Force
In addition to the flow-related electromotive force,enf。, an electrochemical electromotive force, emf, ispresent between the electrodes.The ef。is an electro-chemical emf produced in the flowmeter primary similarto that generated in a battery. It can be similar in magni-tude to enf , and changes slowly. In order to reduce emfe.which would be a measurement bias,an alternating electromagnetic field is used. There exist a number ofvariations of the basic AC and DC fields shown in thisStandard. See para.A-2.1 for additional information.This electrochemical voltage, which varies slowly intime, is substantially reduced in magnitude by utilizingan alternating electromagnetic field.