What media does a target flow meter measure and what is its principle?

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　　The target flow meters produced by my manufacturer are primarily used for measuring the flow rate of fluids with high viscosity and low Reynolds numbers. They have gone through two development stages: pneumatic and electric types. These meters utilize the latest force-sensing sensors as the elements for measurement and signal transmission, and they are also equipped with modern digital intelligence processing technologies to function as advanced flow measurement instruments. 　　A target flow meter has no moving parts, offers high measurement accuracy, and is convenient for installation, maintenance, and use. It also possesses properties such as shock resistance, impurity resistance, and interference resistance; it performs even better, especially in the measurement of fluids with high viscosity and low Reynolds numbers. It has been applied in various media, addressing the challenges associated with flow meters. Target flow meters come in two types: a basic version and a version with temperature and pressure compensation. The basic version measures only the flow rate signal, while the version with compensation can simultaneously measure temperature, pressure, and flow rate; after compensation, it outputs the volume flow rate and mass flow rate under standard conditions. Flowmeters come in two types: tubular and insert type. They can display readings on-site as well as transmit data over long distances. Each type is available in various specifications designed for high temperatures, high pressures, corrosion resistance, and explosion protection, and they also exist in integral and split designs to suit the measurement of different media and various installation environments. 　　The measurement principle of a target flow meter involves placing a force-applying target in the center of the measurement pipe. As the fluid flows past this target, its kinetic energy exerts a force on it, causing the target to move. The magnitude of this force is proportional to the density of the fluid, the area over which the force acts on the target, and the square of the fluid’s flow velocity. It is suitable for measuring liquids and gases; it can also measure mixed media or multiphase flow media to a certain extent. When measuring certain media, the accuracy of the measurement is not affected by vortex formation in the fluid. Target flowmeters have the capabilities to eliminate low-level signals, perform multi-point linear correction, and allow selection of the filtering time; these features enhance measurement accuracy. They can measure bidirectional flow and effectively address various measurement challenges in special processes or application scenarios. In the temperature and pressure compensation type, built-in or external sensors are used to automatically adjust for temperature and pressure, allowing the flow rate under operating conditions to be directly converted into mass flow rate or volume flow rate at standard conditions for measurement. Flow meters of different sizes have varying flow measurement ranges. Even for target flow meters of the same size, their measurement ranges differ when measuring different media, and the actual measurement range must be determined through calculation. 　　The selection of target flow meters can be carried out by referring to the flow meter selection manual. First, it is necessary to know the exact process parameters; one can consult the flow meter selection guide provided by the design institute. The selection can be made by referring to the selection manual, taking into account parameters such as the installation method of the flow meter, nominal diameter, fluid being measured, operating temperature, fluid pressure, output signal, and whether compensation is required. Due to its compact structure, ease of installation and use, as well as short delivery time, the target flow meter is suitable for a variety of applications. The flow range for different media measured by flow meters needs to be determined through calculations; for liquid media, the range is calculated based on the standard flow rate of water, while for gases and vapors, it is calculated based on the standard flow rate of dry air. The flow measurement range of the medium under operating conditions for a given diameter, or the flow measurement range under standard conditions, can be calculated using the maximum or minimum flow rates of standard water or standard dry air. When selecting the diameter, it is necessary to determine the range of volumetric flow rate of the medium to be measured; thereafter, the diameter that can meet the requirements for measuring that volumetric flow rate can be calculated. If the selected nominal diameter differs from the actual diameter of the pipe being measured, it is necessary to use methods such as reducing or enlarging the diameter; it cannot be assumed that the nominal diameter of the flow meter will be suitable just because it matches the inner diameter of the pipe.