指示长期不准;②始终无指示;③指示大范围波动，无法读数;④指示不回零;⑤小流量时无指示;⑧大流量时指示还可以，小流量时指示不准;⑦流量变化时指示变化跟不上;⑧仪表k系数无法确定，多处资料均不一致。 Common problems with electromagnetic flowmeters are: ① long-term inaccurate indication ; ② no indication at all times ; ③ indications fluctuate widely and cannot be read ; ④ indications do not return to zero ; ⑤ no indications at small flows ; The indication is inaccurate when the flow rate is changed ;变化 the indication change cannot keep up when the flow rate is changed ; ⑧ the k- factor of the meter cannot be determined, and many data are inconsistent.
出现问题解决方案总结引起这些问题的主要原因，主要涉及到以下方面： Solutions to the problems of electromagnetic flowmeters summarize the main reasons for these problems, mainly related to the following aspects:
、 电磁流量计选型方面的问题。 1. Problems in the selection of electromagnetic flowmeters . 个规格，实际选型应选择尽可能小的口径，以提高测量精度，这方面的原因主要同问题① 、 ③ 、 ⑥有关。 Some electromagnetic sensors have a larger size in the selection of the caliber or after the design selection due to changes in process conditions. The actual selection should choose the smallest caliber as possible to improve the measurement accuracy. The reason for this is mainly the same as the problem. ① , ③ , ⑥ are related. 工艺条件的变动只是临时的。 For example, an electromagnetic pipeline is designed to be used by several devices. Because the process equipment is sometimes not used, the current actual flow rate is reduced. The actual use causes the original design to be selected too large, which is equivalent to increasing the lower limit of the measurable flow rate. Indications cannot be guaranteed when the flow rate of the process pipeline is small, and can be used when the flow rate is large, because it is sometimes too difficult to rebuild . The changes in process conditions are only temporary. Can be combined with parameter re-tuning to improve the indication accuracy.
、 电磁流量计安装方面的问题。 2. Problems in the installation of electromagnetic flowmeters . 有关。 The main reason is that the length of the straight pipe section in front of the sensor is not enough, which affects the measurement accuracy. The reason for this is mainly related to problem ① . 不用于计量，仅仅用于控制，故目前的精度可以使用相当于降级使用。 For example: The straight pipe section in front of the sensor is obviously insufficient. Since fic203 is not used for metering, it is only used for control, so the current accuracy can be used equivalent to degraded use.
、参数整定方向的原因。 3. Reason for parameter setting direction. 参数错误使得二次仪表满度频率计算错误，这方面的原因主要同问题① 、 ③有关。 Due to the parameter error, the meter indication is wrong . The parameter error causes the secondary meter full-scale frequency to be calculated incorrectly. The main reason for this is related to the problems ① and ③ . The full-scale frequency is similar, which makes the indication inaccurate for a long time. The full-scale frequency calculated by the actual full-scale frequency makes the indication fluctuate widely and cannot be read. The inconsistency of the parameters on the data affects the final determination of the parameters. Re-calibration combined with mutual comparison determined the parameters and solved this problem.
、二次仪表故障。 4 , secondary instrument failure. 系数设定有个别位显示坏，使得无法确定量程设定以及k系数设定，这部分原因主要向问题① 、 ②有关。 This part has many faults, including: once the instrument circuit board has a broken line, the range setting has a single bit display that is bad, the k coefficient setting has a single bit that is bad, making it impossible to determine the range setting and the k coefficient setting. Part of the reason is mainly related to problems ① and ② . The problem was resolved by fixing the corresponding fault.
、四路线路连接问题。 5 , four-line connection problems. 有关。 Some circuits look good on the surface of the circuit. Carefully check that some connectors are actually loose and cause the circuit to be interrupted. Although some connectors are tightly connected, due to the problem of the auxiliary line, the fastening screws are fastened to the wire cover, which also makes the circuit. Interruption, this part of the cause is mainly related to problem ② .
Solutions to problems with electromagnetic flowmeters :
在承包商及设计部门的指导下，对因温度过高而不能满足使用条件的部分流量计重新进行选型，最终选用以聚四氟乙烯为内衬的abgd型流量管，温度范围为-20 ①Under the guidance of the contractor and the design department, re-selection of some flowmeters that cannot meet the conditions of use due to excessive temperature, and finally selected abgd flow tubes with polytetrafluoroethylene as the lining. The temperature range is- 20 -177 ℃ .
将所有流量管上缠绕的伴热线去掉，将伴热线绕过流量管，并将保温材料去掉，使仪表工作在要求的温度范围内。 ②Remove the heating traces wound on all flow tubes, bypass the heating traces, and remove the insulation material to make the instrument work within the required temperature range.
按厂商提供的接地规范对流量计的接线进行整改，将屏蔽线分别连接到变送器和流量管两端，把剥离较长的信号线多余部分增加屏蔽层，将两根屏蔽线分开，并确保连接牢固。 ③ Rectify the wiring of the flowmeter according to the grounding specifications provided by the manufacturer, connect the shielded wires to the transmitter and the flow tube at both ends, add a shield layer to the excess part of the longer signal cable, and separate the two shielded wires And make sure the connection is secure.
将流量管两端的工艺管线增加支援，并确保两端连接法兰在同一水平面上，使流量管尽可能不受力。 ④ Increase the support of the process pipelines at both ends of the flow tube, and ensure that the connecting flanges at both ends are on the same horizontal plane, so that the flow tube is as free as possible. At the same time, process pipelines with straight pipe lengths that do not reach the required length are replaced.
加大巡检及维护力度。 ⑤ Increase inspection and maintenance efforts. Conduct inspections and inspections of all electromagnetic flowmeters twice a day, deal with problems in a timely manner, and regularly clean up sediments and electrodes in flow tubes.
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