ASME MFC-11M:2003 pdf free download

ASME MFC-11M:2003 pdf free download.MEASUREMENT 0F FLUID FLOW BY MEANS OFCORIOLIS MASS FLOWMETERS.
Coriolis meter: a device consisting of a flow sensor (pt-i- mary device) and a transmitter (secondary device), which measures the mass flow by means of the Coriolis force generated by flowing fluid through oscillating tube(s); it may also provide measurements of density and temperature.
cross-talk: if two or more Coriolis meters are to be mounted close together, interference through mechanical coupling may occur. This is often referred to as crosstalk. The manufacturer should be consulted for methods of avoiding cross-talk.
elemental error: the bias and/or precision error associated with a single source or process in a chain of sources or processes (see ASME MFC-IM).
flashing: the formation of vapor bubbles in a liquid when the line pressure falls to or below the vapor pressure of the liquid, often due to local lowering of pressure because of an increase in the liquid velocity (see ASME Ml{-l M).
flow rate: the quantity of fluid flowing though a cross section of a pipe per unit of time (see ASME MFC-IM).
mass flow rate (q,,,): the rate of flow of fluid mass through a cross section of a pipe (see ASME MFC-IM).
voluuw flow rate (qJ: the rate of flow of fluid volume through a cross section of a pipe (see ASME MFC-IM).
flow sensor (primary device): a mechanical assembly consisting of an oscillating tube(s), drive system, measurement sensor(s), supporting structure, flanges/fittings, and housing.
drive system: means for inducing the oscillation of the tube(s).
housing: environmental protection of the flow sensor.
measurement sensor: sensor to detect the Coriolis effect and to measure the frequency of the tube oscillations.
oscdlatutg tube(s): tube(s) through which the fluid to be measured flows.
secondary contour ment: housing designed to provide protection to the environment if the sensor tube(s) fails.
supporting structure: support for the oscillating tube(s).
3.6.6 Housing Design
(a) The housing should be designed primarily to pro- ted the flow sensor from the effects of the surrounding environment (dirt, condensation, and mechanical interference), which could interfere with operation. If the vibrating tube(s) of the CorioLis meter were to fail, the housing containing the tube(s) would be exposed to the process fluid and conditions, which could possibly cause housing failure. It is important to take into consideration the following possibilities:
(1) the pressure within the housing might exceed the design limits
(2) the fluid might be toxic, corrosive, or volatile and might leak from the housing
(b) In order to avoid such problems, certain housing designs provide
(1) secondary pressure containment
(2) burst discs or pressure-relief valves, fluid drains or vents, etc.
For guidelines on specifying secondary pressure containment, see Appendix B.
3.6.7 Cleaning. For general guidelines see para. 3.3.7. Care should be taken to ensure that cleaning conditions (fluids, temperatures, flow rates, etc.) have been selected to be compatible with the materials of the Con- otis meter.
3.7 Transmitter (Secondary Device)
Coriolis meters are mulhvariablc instruments providing a wide range of measurement data from a single connection to the process. The electronics are typically located in an enclosure, which may be mounted locally on the sensor, or remotely, and connected to the sensor using a cable. When selecting the most appropriate transmitter arrangement and options, consideration should be given to the following:
(a) the electrical, electronic, climatic, and safety compatibility
(b) the hazardous area classification of the flow sensor, and transmitter, and the availability of special enclosure options
(c) the transmitter enclosure mounting (i.e., integral or remote)
(d) the number and type of outputs, including digital communications
(e) the ease and security of programming
(f) the meter diagnostic capability, and whether there are output(s) to allow remote indication of system errors
(g) the available input options (e.g., remote zero adjustment, totalizer resetting, alarm acknowledgment)
(h) the capability for local display and operation.