8A2B

The measuring system operates on the principle of Coriolis force measurement. Coriolis force is the force experienced by an object moving linearly within a rotating system. Fc = 2 · ∆m (ν · ω) Fc = Coriolis force ∆m = mass of the moving object ω = angular velocity ν = radial velocity of the object in a rotating or vibrating system The magnitude of the Coriolis force depends on the mass Δm of the moving object and its radial velocity v, i.e., the mass flow. The sensor uses the vibration of the measuring tube instead of the constant angular velocity ω of a rotating system. The fluid flows through the sensor; inside the sensor, two parallel measuring tubes vibrate in opposite directions, similar to a tuning fork. Coriolis forces are generated in the measuring tubes, causing a phase difference in their vibration: • When the flow rate is zero (fluid is stationary), the two measuring tubes vibrate in phase, with no phase difference. • Mass flow causes the measuring tubes to accelerate at the inlet and decelerate at the outlet, creating a phase difference. The greater the mass flow, the greater the phase difference. Electromagnetic phase sensors record the vibration phase at the inlet and outlet of the measuring tubes. The system balance is ensured by the opposite-phase vibration of the two measuring tubes. The measuring principle is completely independent of temperature, pressure, viscosity, conductivity, and fluid characteristics.

Low flow measurement

The integrated Promass A is the ideal choice for continuous process control under harsh conditions. The single-tube flowmeter with self-draining function precisely measures very small flows of liquids and gases, even under high pressure. With economical two-wire loop-powered technology and intrinsically safe design (Ex ia), even using Promass A 200 in hazardous areas provides high operational safety. Heartbeat Technology ensures process safety. • Measuring principle independent of fluid physical properties (e.g., viscosity or density) • Suitable for very small flow measurement in chemical industry applications