ASME MFC-21.1 pdf free download

ASME MFC-21.1-2015 pdf free download.Measurement of Gas Flow by Means of Capillary Tube Thermal Mass Flowmeters and Mass Flow Controllers.
This Standard establishes common terminology and provides guidelines for the quality, description, principle of operation, selection, operation, installation, and flow calibration of capillary tube thermal mass flow- meters and mass flow controllers for the measurement and control of the mass flow rate of gases. The content of this Standard applies to single-phase flows of pure gases and gas mixtures of known composition.
2 TERMINOLOGY, SYMBOLS, AND REFERENCES
2.1 DefinitIons From MFC-1M
accuracy (of ,ncasureme,st): the extent to which a given measurement agrees with a reference for that measurement, often used by manufacturers to express the performance characteristics of a device.
N(YTE: Accun,c,%I is not the same as uncertainty [see uncertainty (qf
bell pnwer: volumetric gaging device used for gases that consists of a stationary tank containing a sealing liquid into which is inserted a coaxial movable tank (the bell), the position of which may be determined. The volume of the gas-tight cavity produced between the movable tank and the sealing liquid may be deduced from the position of the movable tank.
calibration: the experimental determination of the relationship between the quantity being measured and the device that measures it, usually by comparison with a standard, then (typically) adjustment of the output of a device to bring it to a desired value, within a specified tolerance, for a particular value of the input.
critical flow det’ices: a flow meter in which a critical flow is created through a primary differential pressure device (fluid at sonic velocity in the throat). A knowledge of the fluid conditions upstream of the primary device and of the geometric characteristics of the device and the pipe suffice for the calculation of the flow rate.
flow conditioner: general term used to describe any one of a variety of devices intended to reduce swirl and/or regulate the velocity profile.
flow rate: the quantity of fluid flowing through a cross section of a pipe per unit of time.
fulli developed velocity distribution: a velocity distribution, in a straight length of pipe that has zero radial and azimuthal fluid velocity components and an axisymmetric axial velocity profile that is independent of the axial position along the pipe.
laminar flow: flow under conditions where forces due to viscosity are more significant than forces due to inertia, and where adjacent fluid particles move in essentially parallel paths.
NOTES:
(I) laminar flow may be unsteady but is completely free from
turbulent mixing.
(2) Laminar flow In a pipe 1ollow the Poiscuille kiw.
Mach tiumber: the ratio of the mean axial fluid velocity to the velocity of sound in the fluid at thc considered temperature and pressure.
mass flow rate: mass of fluid-per-unit-time flowing through a cross section of a pipe.
piston prover: volumetric gaging device consisting of a straight section of pipe with a constant cross section and of known volume. The flow rate is derived from the time taken by a piston, with free or forced displacement, to travel through this section.
rangeability: the rangeabilitv of a flowmcter is the ratio of the maximum to minimum flow rates (Reynolds numbers, velocities, etc.) in the range over which the meter meets a specified and acceptable uncertainty, also called turndown.
repeatability (qualitative): closeness of agreement among a series of results obtained with the same method on identical test material, under the same conditions (same operator, same apparatus, same laboratory, and short intervals of time).
NOTE: The representative parameters of the dispersion of the population that may be associated with the rsu1Ls are qualified by the term rrpeatabiiit Examples are standard deviation of repeatabilily and variance of repeatability.ASME MFC-21.1 pdf download.