Solutions to problems encountered in the use of vortex flowmeters

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　　Vortex flow meters are primarily used for measuring the flow rate of fluids in industrial pipelines, including various media such as gases, liquids, and steam. Its features include low pressure loss, a wide measurement range, and high precision; when measuring the volumetric flow rate under operating conditions, it is virtually unaffected by parameters such as fluid density, pressure, temperature, and viscosity. There are no moving mechanical parts, thus it offers high reliability and requires minimal maintenance. The instrument parameters can remain stable over the long term. This instrument uses piezoelectric stress sensors, offering high reliability, and can operate within a working temperature range of -20°C to +250°C. It can output both simulated standard signals and digital pulse signals, making it easy to integrate with digital systems such as computers; it is a relatively advanced and ideal flow meter. The main problems are mainly: ① The indication is inaccurate over the long term ； ②No instructions yet ； ③Indicates large-scale fluctuations, making it impossible to obtain a reading ； ④Indicate not to return to zero ； ⑤No indication at low flow rates ； ⑧The indication works fine at high flow rates, but it is inaccurate at low flow rates ； ⑦When the fluid state changes, the indication fails to keep up ； ⑧The K coefficient of the instrument cannot be determined with certainty, as there are no discrepancies in the materials used in various parts. Analysis and Resolution of Key Issues The analysis and resolution of these issues involve problems of varying severity in aspects such as device design, parameter setting, routine maintenance, and the operating environment. Many of these issues are interrelated, and moreover, dealing with some of them requires waiting for certain operational conditions to arise, which poses significant challenges to their resolution. Some issues arise from a combination of different factors, with each factor being related to several different issues. Summarizing the main reasons behind these problems, they mainly relate to the following aspects: 1. Issues with product selection. In some vortex flowmeter sensors, due to changes in process conditions after the selection of the diameter or after the design phase, a larger size is chosen. In practice, it is advisable to select the smallest possible diameter in order to improve measurement accuracy; the reasons for this are mainly related to issues ①, ③, and ⑥. For example, a vortex street flowmeter pipeline is designed to serve several devices; since some of the equipment in the process system is not in use at times, the actual flow rate in operation decreases. As a result, the diameter selected in the original design turns out to be too large, which effectively raises the lower limit of the measurable flow rate. The gauge cannot provide accurate readings when the flow rate is low, but it still functions properly at higher flow rates. After all, it can be difficult to carry out modifications in such cases. Changes in process conditions are usually temporary. Re-tuning of separable parameters to improve indication accuracy. 2. Issues with the device. Mainly, the length of the straight section in front of the sensor is insufficient, which affects the measurement accuracy; this issue is primarily related to problem #1. For example: there is a clear lack of a straight section in front of the sensor.