① The instruction is not correct for a long time;
② No indication at all times;
③ The indication fluctuates widely and cannot be read;
④ Indication does not return to zero;
⑤ No indication in case of small flow;
⑧ The indication is OK in case of large flow but inaccurate in case of small flow;⑦ The indication change cannot keep up with the flow change;
⑧ The K-factor of the instrument cannot be determined, and many data are inconsistent.
Due to the complexity of the problems, there are problems of varying degrees in juice design and installation, parameter setting, daily maintenance, and operating environment. Many problems are related to each other. In addition, some problems need to wait for a certain time for process operation to solve, which brings great difficulties to solve the problems. Some problems are caused by different reasons, and some are related to different problems.Causes of Common Problems in the Use of Vortex Flowmeters:
(1)Model selection. For some vortex street sensors, due to the change of process conditions in the aperture selection or after the design selection, a larger size has been selected. In the actual selection, the aperture should be as small as possible to improve the measurement accuracy. The reason for this is mainly related to problems ①, ③, and ⑥. For example, a vortex street pipeline is designed to be used by some equipment. Due to the fact that some equipment in the process is not used sometimes, the actual use flow is reduced. The actual use causes the original design selection caliber to be too large, which is equivalent to increasing the lower limit of measurable flow. The indication of the processing pipeline cannot be guaranteed when the flow is small, and it can still be used when the flow is large Because it is too difficult to rebuild (sometimes, changes in process conditions are only temporary). It can be combined with parameter re-adjustment to improve indication accuracy.
(2)Installation problems. The main reason is that the length of the straight pipe in front of the sensor is not enough, which affects the measurement accuracy. The reason for this is mainly related to problem ①.
(3)Reason for parameter setting direction. Due to the parameter error, the instrument indication is incorrect. The parameter error makes the calculation of the full frequency of the secondary instrument wrong. The reason for this is mainly related to the problems ① and ③. The similar full-scale frequency makes the indication inaccurate for a long time. The actual full-scale frequency greatly interferes with the calculated full-scale frequency, which makes the indication fluctuate in a large range and cannot be read. The inconsistency of the parameters in the data affects the final determination of the parameters. Finally, the parameters are determined through re-calibration and mutual comparison, solving this problem.
(4)Secondary instrument failure. There are many failures in this part, including there is disconnection on the primary instrument circuit board, some bits of the range sets are bad, and some bits of the K factor sets are bad, which makes it impossible to determine the range setting and K factor setting. This part of the reason is mainly related to problems ① and ②. The problem was solved by fixing the corresponding fault.
(5)Four-circuit connection problem. On the surface, some circuits are well connected. Check carefully. Some connectors are actually loose, causing circuit interruption. Some connectors are tightly connected, but the fastening screws are fastened on the cover due to the secondary line problem, which also causes circuit interruption. This part of the reason is mainly related to problem ②. The corresponding line problems have been solved, and the existing problems have also been solved accordingly.
(6)Connection between the secondary instrument and subsequent instrument. The mA output circuit of the secondary instrument is interrupted due to the problems of the subsequent instrument or the maintenance of the subsequent instrument. For this type of secondary instrument, this part of the reason is mainly related to problem ②. Especially for the subsequent recorders, when the recorders are damaged for a long time and cannot be repaired, it is important to short-circuit the output of the secondary instrument.
(7)There is no indication in the circuit due to the failure of the horizontal axis cable of the secondary instrument. Due to the long-term operation and the influence of dust, the flat shaft cable failure is caused. The problem can be solved by cleaning or replacing the flat shaft wire.
(8)The problem ⑦ is mainly caused by the looseness of the fixing screw of the secondary instrument display head coil, which causes the head to sink, the friction between the pointer and the case is large, and the action is not flexible. The problem is solved by adjusting the head and fixing it again.
(9)Use environmental problems. Especially for the sensor part installed in the shaft, the circuit board is affected by dampness due to high ambient humidity, which is mainly related to problems ② and ③. Through the corresponding technical transformation measures, the probe part and the conversion part of some sensors with high environmental humidity were separated again, and the separated sensor was used instead, so the working environment was improved. Recently, this part of the instrument operated well.
(10)Due to poor on-site calibration, or due to changes in the actual situation after calibration. The indication problem is caused by the poor adjustment of vibration and noise balance and sensitivity on site or the further change of site conditions after a period of operation after adjustment. This part of the reason is mainly related to problems ④ and ⑤. Use the oscilloscope and readjust it according to the process operation.(11) The reason why problem ⑧ is raised separately is that this problem has affected the analysis and solution of the problem for a long time. Since the Chemical Plant does not have the conditions for K-factor calibration, the K-factor can only be based on the data provided by the manufacturer. Due to some changes in the manufacturer itself, the K-factor on the data provided is inconsistent, which affects the solution to the problem. By looking for conditions to recalibrate, or by repeatedly modifying and comparing, the unified instrument parameters were finally determined.