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Flow measurement is an important basis for corporate economic accounting. Accurate and reliable flow measurement is a prerequisite for ensuring the normal operation of enterprises, and it is one of the key means to achieve optimal economic benefits. The following details the twelve basic principles that must be considered when installing compressed air flow meters: The first principle is the consistency of pipe diameter. The inner diameter of the measuring tube of the installed compressed air flow meter should be identical to that of the pipeline. When the inner diameter of the measuring tube of the selected compressed air flow meter is smaller than or larger than the inner diameter of the process pipeline, transition fittings must be used at both ends to ensure consistency in the inner diameter and to meet the requirements regarding straight sections of pipe. Second, the principle of ease of maintenance. The installation location should be easy to maintain, and a maintenance platform should be added if necessary. Third, the principle of reducing and minimizing external interference. It should be installed in a location that is as free as possible from external interference. For example, it should be kept away from sources of vibration and not installed in areas such as compressor rooms; it should also be far away from sources of electromagnetic interference, for instance, not installed near frequency converters. Furthermore, it should be properly and reliably grounded. Fourth, the full-pipe flow principle. Except for open-channel flow meters, when installing a flow meter, it is necessary to ensure that the fluid can flow completely through the pipe. If necessary, the installation height can be reduced so that the flow meter’s measuring tube is below the process pipeline, thereby meeting the requirement for full-bore flow. In some cases, the flow of fluid can be changed from top to bottom to bottom to top in order to ensure full-bore flow. Fifth, the emission principle. Liquid fluids may contain gas or have liquid vaporization, while gaseous fluids may condense or contain liquid; these factors can change the flow cross-sectional area. Therefore, a drainage device should be installed at the lowest point of the process pipeline where the flow meter is located, and an exhaust device at the highest point, to facilitate drainage and exhaust. Sixth, the flushing principle. For fluids that crystallize, precipitate, or become contaminated, a flushing pipeline should be provided to facilitate the cleaning of pressure guide tubes and detection areas. Seventh, the principle of preventing excessive stress. When connecting the flow meter’s measurement tube flange to the adjacent process pipe inlet flange, it is necessary to prevent excessive stress from being applied, as this could affect the flow meter. Eighth, the principle of alignment of axes. The axis of the flowmeter measuring tube should be aligned with that of the process pipeline; it is essential to properly align it with the process pipeline’s axis to ensure proper coaxiality. Ninthly, fully utilize the principles of pipe flow. To ensure that the fluid flow is a fully developed pipe flow, it is necessary to maintain specified lengths of straight sections upstream and downstream, as well as meet required pipeline roughness standards; flow regulators should be installed if necessary. Tenth, the principle of reducing resistance. Minimize the number of fittings installed, and use connection fittings with low flow resistance wherever possible. For example, can two 90° elbows on the same plane be replaced with two 45° elbows, etc.? Eleventh, principles for installing control valves. The control valve used to regulate this flow rate should be installed downstream of the flow meter and meet the requirements regarding the length of the straight pipe section downstream. Twelfth point: Cleaning and welding principles. The flowmeter should be installed after the process pipeline is cleaned. When welding process flanges, short and long pipes such as those used in flow meters are used as substitutes.