The turbine flowmeter is common flow meter. It is one of the most precise and reproducible flow meters. Turbine meters have a fairly high flow rate, good long-term and short-term repeatability, and are usually linear above the first 10 to 20% of the flow rate.
Turbine meters evaluate stream speed by counting a rotor’s amount of revolutions spinning as the fluid passes through its blades.
The meter may contain an electronic detector that divides a rotor revolution into pulses. The readout records the variables and transforms them into a separate variable recognized as the reference Pulse Factor or “K-factor” into the specified volume stream speed.
The stream meter should be inspected for overseas content before assembly and to guarantee that the turbine is spinning freely.
Any debris should also be removed of all downstream liquid lines. Also, be sure to shut down the liquid stream and release all the stress in the pipes before placing the stream meter in the current scheme.
The stream meter must be mounted with the arrow of the stream column pointing in the liquid stream direction. On the bottom of the stream meter you can find the stream direction button.
The stream meter is intended to operate in any direction, but having the meter mounted in horizontal piping is the desired direction.
The performance of flowmeter can be affected by swirl. Flow conditioning is used for swirl & non-uniform velocity profile. Flow condition requires sufficient length of a straight pipeline or combination of pipelines that are inserted in the meter run upstream or downstream of the turbine meter.
Straight-pipe recommendations include:
- 20 pipe diameters for 90-degree elbow, tee, filter, strainer, or thermowell
- 25 pipe diameters for a partially open valve; and
- 50 pipe diameters for two elbows in different planes or if the flow is spiraling
Turbine meters involve downstream assembly of straightening valves and drying strainers or filters. Straightening valves may otherwise decrease the lengths of a straight tube. Strainers and filters eliminate the substances in the liquid that could otherwise harm the rotor of the engine.
Because pumps mounted in the piping can trigger major mistakes, use full-bore shut-off valves that are completely accessible during the procedure of the meter. Only install control valves on the side of the meter upstream.
A sudden pressure drop upstream can result in flashing or cavitations within the turbine meter. Flashing causes the meter to read high, while cavitations result in rotor damage.
If a bypass line is not used, all fluid control units should be situated upstream of the stream meter as shown in the below figure: