What is a turbine flowmeter?
In a turbine flowmeter, the vane rotor hangs axially in the flow and rotates at a rate proportional to the fluid velocity.
In some models, the rotor blades are made of a magnetic material that induces alternating voltage in the signal pickup coil.
In other designs, the rotation speed is detected by a radio frequency pickup, with a high-frequency carrier signal modulated by the rotating blades.
Turbine flowmeters are very accurate in good condition, but they are fragile and costly to maintain.
Turbine meters are computational types that have been used since the 1960s and with the improvement of their technology, they have become more popular among companies.
These meters determine the mass flow of the current by measuring the speed of each blade rotor that is floating inside the current.
The rotational speed of the rotor is proportional to the mass flow.
For petroleum products, the volumetric flow rate is equal to the product of the cross-sectional area of the flow and the speed of the rotor, in which the measurement coefficient is applied and temperature and pressure corrections are made.
The calculation method for natural gas is the same as above, except that the compressibility property must also be considered.
The performance of turbine meters is excellent in case the flow rate is uniform and the fluid properties are compatible (density and viscosity do not change).
In fact, these counters want a smooth and direct flow, and therefore a direct pipe is used before oil or natural gas enters these counters and also after leaving the flow.
If there is not enough space to install a straight pipe, smoothing blades (small pipes inside lines with larger diameters) are used.
These types of counters are used for LIQUID SERVICE and GAS SERVICE.
Advantages of a turbine flowmeter
- They are small in size and light in weight.
- They are very linear and reproducible.
- They are cheaper than other types of flowmeters.
- Due to the limited mechanical parts, they need a small number of repairs.
- They are one of the most reliable flowmeters with dual pulse output capability.
Disadvantages of turbine flowmeter
- They have a low operating range in high viscosity fluid operating services.
- Their performance is highly dependent on the viscosity of the fluid.
- They are only suitable for completely single-phase currents.
- They are highly dependent on the upstream profile.