This type of meters consists of an impeller mounted on a vertical axis using proper bearings. The rotor has a specific number of blades positioned at an angle to the stream. The flow on the blades causes the rotor to rotate.
The rotor velocity is directly proportional to the fluid velocity. Magnets in the rotor cause pulses. This is picked up by magnetic coupling and is converted to proportion current signal. Flow deflectors are used in case of low velocity gas flows to increase the velocity.
They offer high accuracy and integrity.
Turbine flow meters also can be used in high pressure and temperature services. They are used for measurement of fuel oils, final products, etc. But Turbine flow meters are very expensive.
Turbine meters are available for liquid and gases services.