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Limitations of the use of turbine flowmeters

Although the turbine flowmeter has a high viscosity type and is suitable for high-pressure measurement, it does not need to be opened on the meter body, and it is easy to be made into a high-pressure type instrument. The repeatability is good, and the short-term repeatability can reach 0.05%-0.2%, which is due to good repetition. Sex, such as frequent calibration or online calibration accuracy, is the preferred flow meter in trade settlement. However, there are still limitations in the use process:

(1) Although the turbine flowmeter has a high viscosity type, the common type is not suitable for a medium of higher viscosity. The increase of the viscosity of the medium increases the lower limit of the flowmeter measurement, the range is reduced, and the linearity is deteriorated.

(2) Fluid properties (density, viscosity) have a great influence on flow characteristics. Gas turbine flowmeters are susceptible to density, while liquid flowmeters are sensitive to viscosity changes, and because density and viscosity are closely related to temperature and pressure. It is difficult to avoid the fluctuation of temperature and pressure on site. It is necessary to take supplementary (correction) measures according to the degree of influence on accuracy to maintain measurement accuracy.

(3) The influence of the flow velocity distribution distortion and the swirling flow of the instrument is large, and the straight pipe section required for the upstream and downstream of the sensor is long. If the installation space is limited, a flow regulator (rectifier) can be added to shorten the length of the straight pipe section.

(4) The requirements for the cleanliness of the measured medium are high, which limits the field of use. Although it is possible to install a filter or the like to eliminate the dirty medium, it also causes side effects such as an increase in pressure loss and an increase in maintenance amount.

(5) It is not possible to maintain the calibration characteristics for a long time, and it needs to be periodically checked. For liquids without lubrication, the liquid contains suspended matter or abrasive liquid, which causes the bearing wear and jam problems to be prominent, which limits the scope of use. After using carbide shafts and bearings, the situation is much better than graphite bearings. For high accuracy measurement requirements such as trade storage and transportation, it is best to have on-site calibration equipment that can be periodically verified to maintain its characteristics.

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