ABB CoriolisMaster FCM2000, Operating Instructions Manual

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Design and function
D184B111U02 CoriolisMaster FCM2000 17
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2 Design and function
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2.1 Design
The ABB Automation Products Mass Flowmeter operation is based on the Coriolis principle.
The MC2 construction uses the classical parallel meter pipes and is characterized, in particular,
by a space saving and rugged design, a wide flowmeter size spectrum at an advantageous
price to the customer.
G00355
Fig. 7 MC2 Parallel Pipe Construction
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2.2 Measuring principle
When a mass flows through a vibrating pipe, Coriolis forces are generated which bend and twist
the pipe. These very small pipe deformations are measured by optimally mounted sensors and
electronically evaluated. Because the measured phase shift of the sensor signals is proportional
to the mass flowrate, the Coriolis Mass Flowmeter measures the mass flowrate in the flowmeter
directly. The metering principle is independent of the density, temperature, viscosity, pressure
and conductivity of the fluid.
The meter tubes always vibrate at resonance. This resonant frequency, at the operating
conditions, is a function of the meter tube geometry, the characteristics of the flowmeter
materials and the mass of the fluid in the meter tube, which is also vibrating. It provides an
accurate measure of the density of the fluid being metered.
An integrated temperature sensor measures the fluid temperature and is utilized for corrections
to temperature dependent instrument parameters. Summarizing, it is possible to simultaneously
measure the mass flowrate, fluid density and temperature with the Coriolis Mass Flowmeter.
Other measurement values can be derived from these values, e.g. volume flowrate or
concentration.