The main advantages and disadvantages of vortex flowmeters

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This post was last edited by zhaohh3211 on 2012-2-18 at 15:10. Advantages and disadvantages of vortex flowmeters. Limitations of vortex flowmeters: A vortex flowmeter is a type of velocity-based flowmeter, and the stability of vortex separation is affected by the flow velocity distribution; therefore, it requires certain straight pipe sections, typically 10D in front and 5D behind. When measuring liquids, the upper limit of flow velocity is restricted by pressure losses and the phenomenon of cavitation, usually around 10 meters per second. When measuring gases, the upper flow velocity is limited by the compressibility changes of the medium, while the lower flow velocity is constrained by the Reynolds number and the sensitivity of the sensor. The flow velocity range for ordinary gases is 10–70 meters per second, whereas for steam it is 8–50 meters per second. Stress-type vortex flow meters are sensitive to vibrations; therefore, when installing such meters in pipes with high vibration levels, appropriate vibration-damping measures must be taken. These meters use piezoelectric crystals as sensing elements, which means they are subject to temperature constraints, with typical operating temperatures ranging from -40°C to +350°C or from -10°C to +250°C. “What are the characteristics and limitations of vortex flowmeters? Vortex flowmeters are a new type of flowmeter that has been developed based on the Karman vortex street principle, and they represent an internationally advanced technology. Thanks to advantages that other flowmeters do not possess, they have seen rapid development since the 1970s. According to available data, the use of vortex flowmeters has increased significantly in developed countries such as Japan, Europe, and the United States; they are widely used in various fields and are likely to play a dominant role among flowmeters in the future. They represent the ideal alternative to orifice plate flowmeters and are currently the preferred choice for flowmeter use in China. 1. Features of the “vortex flow meter”: It has a simple and robust structure, no moving parts, high reliability, and performs well over long periods of time; it is easy to install and convenient to maintain; the sensing element does not come into direct contact with the fluid, ensuring stable performance and a long service life; it outputs pulse signals proportional to the flow rate, with no zero-point drift, high accuracy, and it is easy to connect to computers; it has a wide measurement range, with a ratio of up to 1:10; it causes minimal pressure loss, resulting in low operating costs and improved energy efficiency; within a certain range of Reynolds numbers, the frequency of the output signal is not affected by changes in the physical properties or composition of the fluid, and the instrument coefficient depends only on the shape and size of the vortex generator; there is no need for compensation when measuring the volumetric flow rate of the fluid, and no re-calibration of the instrument’s coefficients is required after replacing components. It has a wide range of applications, capable of measuring the flow rate of steam, gases, and liquids; the calibration period is two years. Second, the limitations of vortex flowmeters: A vortex flowmeter is a type of velocity-based flowmeter, and the stability of vortex separation is affected by the flow velocity distribution; therefore, it requires certain straight pipe sections, typically 10D in front and 5D behind. When measuring liquids, the upper limit of flow velocity is restricted by pressure losses and the phenomenon of cavitation, usually at 10 meters per second. When measuring gases, the upper flow velocity is limited by the compressibility changes of the medium, while the lower flow velocity is restricted by the Reynolds number and the sensitivity of the sensor. The flow velocity range for ordinary gases is 10–70 meters per second, whereas for steam it is 8–50 meters per second. Stress-type vortex flow meters are sensitive to vibrations; therefore, when installing such meters in pipes with high vibration levels, appropriate vibration-damping measures must be taken. These meters use piezoelectric crystals as sensing elements, which means they are subject to temperature constraints, with typical operating temperatures ranging from -40°C to +350°C or from -10°C to +250°C.