Proline Prowirl 72F, 72W, 73F, 73W
Hauser
3
Function and system design
Measuring principle
Vortex meters work on the principle of the Karman vortex street. When luid flows past a bluff body, vortices
are alternately formed on both sides with opposite directions of rotation. These vortices each generate a local
low pressure. The pressure fluctuations are recorded by the sensor and converted to electrical pulses.
The vortices develop very regularly within the permitted application limits of the device.
Therefore, the frequency of vortex shedding is proportional to the volume flow.
A0003938
The K-factor is used as the proportional constant:
A0003939-EN
Within the application limits of the device, the K-factor only depends on the geometry of the device. It is
independent of the fluid velocity and the fluid properties viscosity and density. In this way, the K-factor is also
independent of the type of matter that is to be measured, regardless of whether this is steam, gas or liquid.
The primary measuring signal is already digital (frequency signal) and linear to the flow.
After production, the K-factor is determined in the factory by means of calibration and is not subject to long-
time or zero-point drift.
The device does not contain any moving parts and does not require maintenance.
v
K-Factor =
Pulses
Unit Volume [dm³]
