Common problems and solutions in the use of vortex flowmeters

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Frequently asked questions: The main ones are: ① The indication is inaccurate for long periods of time； ②No instructions have been given ； ③The indicator shows that the overall plan is not firm; no reading can be obtained ； ④Indicate not to return to zero ； ⑤No indication at low flow rates ； ⑧The indication is okay at high flow rates, but inaccurate at low flow rates ； ⑦Indicates that the changes in traffic cannot keep up ； ⑧The surface K coefficient cannot be determined, as there are discrepancies in various sources. The solutions involve the following aspects: 1. Questions regarding product selection. For some vortex flow meter sensors, the diameter chosen during the initial selection process might end up being one size too large due to changes in technical conditions; therefore, the smallest possible diameter should be selected to improve measurement accuracy. The reasons for this are mainly related to issues ①, ③, and ⑥. For example, a vortex flow meter pipeline is planned to supply several devices; due to technical constraints, some of these devices are not used at times, which results in a reduced actual flow rate. As a consequence, the pipe diameter chosen initially turns out to be too large, which in effect raises the lower limit of the measurable flow rate. The meter cannot provide accurate readings when the flow rate is low, but it still functions fine when the flow rate is high. Reconstructing the pipeline from scratch can sometimes be too difficult. Changes in skill requirements are only temporary. The forward indication accuracy can be retuned from scratch using the controllable parameters. 　　2. Questions regarding the equipment. Mainly, the length of the straight section in front of the sensor is not appropriate, which affects the measurement accuracy; this issue is primarily related to question ①. For example, the straight section in front of the sensor is significantly shorter; since FIC203 is not used for measurement but only for control, its current accuracy can be considered as equivalent to a degraded level of performance. 　　3. Reasons for the parameter tuning direction. The surface indication is incorrect due to parameter errors. Parameter errors lead to inaccuracies in the calculation of the secondary surface fullness frequency, and the reasons for this are mainly related to questions ① and ③. A significant difference in the full-scale frequency leads to inaccurate readings over an extended period of time. When the full-scale frequency is much higher than the calculated value, the readings become unstable and unreadable. Moreover, variations in the parameters listed in the data affect the accurate determination of these parameters; ultimately, this issue was resolved by recalibrating and making comparative assessments to determine the parameters accurately. 　　4. Secondary surface defects. This has several drawbacks, including: in cases where there are broken wires on the surface circuit board, the range setting can become invalid due to the corruption of a single bit, and the K coefficient setting can also become invalid due to the corruption of a single bit; as a result, it becomes impossible to determine the correct range setting or K coefficient value. These issues are mainly related to questions ① and ②. By correcting the relevant shortcomings, the doubts were resolved. 　　5. Questions regarding the connection of four circuits. In some circuits, the wiring connections appear to be in good condition at first glance; however, upon closer inspection, it is found that some connectors are actually loose, resulting in interruptions in the circuit. In other cases, although the connectors are tightly connected, issues with the auxiliary wires cause the fastening screws to be tightened onto the wire insulation, which also leads to circuit interruptions. These problems are mainly related to issue #2. 　　The relevant line-related questions were addressed, and any existing doubts were also resolved accordingly. 　　6. Questions regarding the connection between the secondary surface and the subsequent surfaces. Due to issues with the subsequent surface, or perhaps as a result of repairs to that surface, the mA output circuit of the secondary surface becomes interrupted. For this type of secondary surface, the reasons for this are mainly related to issue #2. Especially for subsequent recorders, when the recorder is damaged for an extended period and cannot be repaired, care must be taken to prevent short-circuiting of the output from the secondary surface. 　　7. Due to the shortcomings of the secondary surface flat-axis cable, there is no indication when a circuit is formed. Due to long hours of operation and exposure to dust, these factors become drawbacks of flat cable systems; the problem can be resolved by cleaning or replacing the flat cables. 　　8. Regarding question ⑦, it was mainly caused by the loosening of the fixing screws for the gauge coil on the secondary surface, which led to the gauge sinking; as a result, the pointer came into excessive contact with the gauge case, causing poor performance. The issue was resolved by adjusting the gauge and re-fixing it properly. 　　9. Use environmental questions. In particular, for some sensors located in the boreholes, high environmental humidity causes the circuit boards to become damp; this is mainly related to issues numbered ② and ②. Through appropriate technical modifications, some sensors that operated in high environmental humidity had their probes either replaced or modified; separate-type sensors were used as a substitute, thereby improving the working environment. So far, the results of these efforts have been excellent. 　　10. Due to inadequate on-site calibration, or perhaps due to further changes in the actual conditions after calibration. This is due to inadequate adjustment of the on-site vibration and noise balance as well as sensitivity settings. Perhaps due to changes in the on-site situation after working for some time following the adjustment, instructions become problematic; these reasons are mainly related to issues ④ and ⑤. Use an oscilloscope, along with communication skills, to adjust it from scratch. 　　11. Question ⑧ was raised separately because it has had a significant impact on the analysis and handling of other questions for a long time. Since Dongfang Chemical Plant does not have the conditions necessary for calibrating the K coefficient, this coefficient can only be determined based on the data provided by the manufacturer. However, due to certain changes made by the manufacturer, the K coefficients in the various datasets supplied are inconsistent, which hinders the processing of these questions. By seeking conditions for initial calibration, and perhaps through repeated corrections and comparisons, the common surface parameters were ultimately determined.