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Mass flowmeter and vortex flowmeter advantages and disadvantages big PK

The flow meter plays an important role in the development process. The flow meter is one of the major instruments in process automation instrumentation and devices. It is widely used in metallurgy, electric power, coal, chemical industry, petroleum, transportation, construction, textile Various fields of national economy such as food, medicine, agriculture, environmental protection, and people’s daily life. In accordance with the current most popular and most extensive classification method, it is divided into: volumetric flowmeter, differential pressure flowmeter, floater flowmeter, turbine flowmeter, electromagnetic flowmeter, vortex flowmeter in fluid oscillation flowmeter, quality Flow meters and plug-in flow meters, probe flow meters. Now we will introduce the advantages and disadvantages of the mass flowmeter and vortex flowmeter.
The advantages and disadvantages of mass flowmeters
Mass Flow Meter Advantages: Mass flow meters measure mass flow directly and have high measurement accuracy. A wide range of measurable fluids includes various liquids of high viscosity liquids, solids-containing slurries, trace gas-containing liquids, and medium- and high-pressure gases of sufficient density. The vibration amplitude of the measuring tube is small and can be considered as a non-moving part. There are no obstacles and moving parts in the measuring tube. Corresponding to the inflow flow velocity distribution is not sensitive, so there is no upper and lower straight pipe requirements; measured values are not sensitive to fluid viscosity, fluid density changes have little effect on the measured value; can be multi-parameter measurement, as the period of measurement density, and thus Derived the concentration of solute contained in the measurement solution.
Disadvantages of the mass flowmeter: Zero drift of the zero point of the mass flowmeter causes the drift of the zero point, which affects the further improvement of its accuracy. As a result, many types of meters have to use the total error as the basic error and the zero-point instability measurement. Mass flow meters cannot be used to measure low-density media and low-pressure gases; exceeding a certain limit in the liquid content can significantly affect the measured value. The mass flowmeter is sensitive to the external vibration interference. In order to prevent the influence of the pipeline vibration, most of the model cmf flow sensors require a relatively high installation and fixation. Can not be used for larger diameters, currently limited to less than 200mm; wear and corrosion of the inner wall of the measuring tube or deposition fouling will affect the measurement accuracy, especially for the thin-wall tube measuring tube mass flowmeter is more significant; pressure loss greater , And volumetric instrument is equivalent, some models even larger than the volume meter cmf 100%; most models of mass flowmeter weight and volume larger. expensive. A foreign set price is about 2 to 5 times that of an electromagnetic flowmeter of the same caliber; the domestic price is about 2 to 8 times that of an electromagnetic flowmeter.
The advantages and disadvantages of vortex flowmeters
Advantages of vortex flowmeter: The vortex flowmeter has a simple and firm structure. Compared with a throttling differential pressure flowmeter, the vortex flowmeter has a simple and firm structure. It does not require a pressure control tube and a three-valve manifold to reduce leakage, blockage and freezing. There are many types of fluids available, such as liquids, gases, vapors, and partially miscible fluids. Accuracy teaches high, generally measured values r, range width up to 10:1 or 20:1, small pressure loss. Output pulse signal proportional to flow, suitable for total measurement, no zero drift; within a certain range of Reynolds number, the output frequency signal is not affected by fluid properties and components, that is, the meter coefficient only with the vortex generating body and pipeline Depends on the size of the shape, only need to verify in a typical media and apply to various media. According to the measuring object, the corresponding detection method can be selected, and the instrument has strong adaptability. Vsf is a meter that is more likely to be dry only in a variety of flow meters.
Vortex Flowmeter Limitations: Vortex flowmeters are not suitable for low Reynolds number measurements and are therefore limited in applications with high viscosity, low flow rates, and small bore diameters. The stability of the vortex separation is affected by the distortion of the flow velocity distribution and the influence of the swirling flow. A sufficiently long straight pipe section or a flow regulator should be installed according to the different types of flow blockers on the upstream side. Generally, the throttling differential pressure flowmeter can be used as a reference. Pipe length requires installation. The force-sensitive detection method vsf is sensitive to the mechanical vibration of the pipeline and is not suitable for strong vibration. Compared with the turbine flow meter, the meter coefficient is low, the resolution is low, and the larger and lower the bore diameter, the full tube flowmeter is generally used below dn300. The instrument still lacks theoretical research and practical experience in pulsation flow and miscible flow.

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