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Under specific flow conditions, part of the fluid’s kinetic energy in a steam flow meter is converted into fluid vibration, and the vibration frequency has a definite proportional relationship with the flow velocity (flow rate). Flow meters that operate on this principle are known as fluid vibration flow meters. 1 Field Applications Steam flowmeters can be used with a wide range of fluids, but they are not suitable for fluids with low Reynolds numbers (ReD≤2×104). Because at low Reynolds numbers, the Strouhal number varies with Reynolds number, resulting in poorer linearity of the instrument. At the same time, the erosion of the vortex generator by a fluid containing solid particles generates noise, and if the short fibers in such a fluid become entangled around the vortex generator, it will alter the meter coefficient. The applications of steam flow meters in multiphase fluids are as follows: ① They can be used in gas-liquid two-phase flows that contain dispersed and uniform tiny bubbles, with a volume gas content of less than 7%–10%; if the volume gas content exceeds 2%, the meter coefficient must be adjusted. ②It can be used in gas-solid and liquid-solid two-phase flows containing dispersed and uniform solid particles, with a content of no more than 2%. ③It can be used for two streams of immiscible liquids (such as oil and water), etc. Pulsating flow and rotating flow can have a severe impact on vortex flow meters. If the pulsation frequency coincides with the frequency band of the vortex street, it can cause resonance, disrupting normal operation of the equipment and leading to a \"lock-in\" phenomenon in the vortex street signal; in this case, the signal remains fixed at a certain frequency. “\"Locking\" is related to factors such as pulsation amplitude, vortex generator shape, and blockage ratio. The accuracy of steam flow meters is roughly between ±0.5%R and ±2%R for liquids, and between ±1%R and ±2%R for gases; the repeatability is generally 0.2% to 0.5%. Due to the low meter coefficient of vortex flowmeters, their low frequency resolution, and the fact that accuracy decreases as the diameter increases, the diameter of such meters should not be too large (below DN300). A wide range is a characteristic of vortex flowmeters, but the important factor is the flow value at the lower limit of the measurement range. The minimum average flow velocity for liquids is generally 0.5 m/s, while for gases it is 4–5 m/s. The normal flow rate for a vortex flow meter is at 1/2 to 2/3 of the normal measurement range. The advantage of steam flowmeters is that their coefficient of performance is not affected by the properties of the medium being measured, allowing them to be applied from one typical medium to other mediums. However, due to the large difference in flow rates of liquids and gases, the frequency range also varies significantly. In the amplifier circuit used to process vortex street signals, the passband of the filter varies, and thus the circuit parameters also change; therefore, the same circuit parameters cannot be used to measure different media. Furthermore, the density difference between gases and liquids is significant, and the signal strength generated during vortex separation is proportional to density; therefore, the difference in signal strength is also large. The gain and trigger sensitivity of liquid and gas amplifier circuits are different; the piezoelectric charges vary greatly, and the parameters of charge amplifiers also differ. Even when they are all gases (or liquids, vapors), the operating flow range and signal strength vary depending on the pressure, temperature, and density of the medium, and the circuit parameters also need to be adjusted accordingly. Therefore, it is not feasible to use a vortex flow meter without making any hardware or software modifications, nor is it possible to change the medium used or the diameter of the instrument. 2 Installation Precautions Steam flow meters are types of flow meters that are sensitive to distortions in the flow velocity distribution within pipes, as well as to rotational flows and flow fluctuations. Therefore, due attention must be paid to the installation conditions of the pipes on-site, and the instructions provided in the user manual must be followed strictly. Vortex flow meters can be installed indoors or outdoors. If installed in a well, to prevent flooding, a dew-type sensor should be used. Sensors can be installed on pipes horizontally, vertically, or at an angle. When measuring liquids and gases, it is important to pay attention to the installation location in order to avoid interference from bubbles and droplets; for flow meters used to measure liquids and gas-liquid mixtures, it is essential that there be sufficient length of straight pipe sections upstream and downstream of the meter. Vortex flow meters require such straight pipe sections as well. a is a 90° elbow, b is a concentric expansion, c is a fully open concentric reduction valve, d are two 90° elbows on different planes, e is a partially open control valve, f are two 90° elbows on the same plane. When connecting sensors to pipes, the following issues need to be taken into account. ①The inner diameters D of the upstream and downstream piping are equal to the inner diameter D’ of the sensor, with the difference satisfying the following condition: 0.95D ≤ D’ ≤ 1.1D ； ②The piping of the steam flow meter should be concentric with the sensor, with a coaxiality of less than 0.05D’ ； ③The gasket must not protrude into the pipe, and its inner diameter may be 1–2 mm larger than that of the sensor ； ④To perform flow interruption checks and clean the sensor, a bypass pipe should be installed ； ⑤Reducing the impact of vibration on vortex flowmeters should be considered a key issue in their on-site installation. First, when selecting the location for installing the sensor, try to avoid areas with vibration sources ； Secondly, the use of elastic hoses for connection can be considered ； Third, installing pipe supports is an effective vibration reduction method. When electrically installing steam flow meters, it is important to use shielded or low-noise cables to connect the sensor and the converter, with the distance between them not exceeding the values specified in the user manual. During wiring, it should be kept away from high-power power cables, and preferably protected with a separate metal sleeve. The \"one-point grounding\" principle should be followed, with the grounding resistance to be less than 10Ω. Both the integral and separate types should be grounded on the sensor side, and the grounding point of the converter housing should be at the same potential as that of the sensor. For more information, please visit the company’s official website at http://www.yb1518.com/. Please keep this link when reproducing the content! http://www.yb1518.com/UploadFiles/20135413012298.jpg