Pressure and temperature selection
The actual working pressure of the fluid in the pipeline should be less than the rated working pressure of the flowmeter. Pay attention to whether there is negative pressure in the pipeline, such as the evaporation process, and the negative pressure is up to -60KPa. Such working conditions should be communicated with the manufacturer's technicians when ordering. Strict requirements are imposed on the lining material. The actual temperature should meet the temperature requirements specified by the flowmeter.
Power supply selection
The choice of the electromagnetic flowmeter power supply should be selected according to the flowmeter itself and the environment of the site. If the site allows, the power supply is convenient, safe and easy to maintain. As a chemical company, more than 90% of the raw materials and process links are in the liquid phase. During operation, the internal humidity of the workshop is large, and no flammable gas is generated during the whole operation. It is safer to use DC24V for power supply. Outdoor dry environment, choose AC220V power supply, convenient lead wire, good maintenance and low cost.
Some explosion-proof occasions, such as flowmeters used in gas boilers, are ideal for battery-powered electromagnetic flowmeters.
Vortex flowmeter analysis and solution
Summarizing the main causes of these problems, mainly related to the following aspects:
1. Problems with selection. Some vortex sensors are selected on the caliber selection or after the design selection, due to the change of process conditions, so that the selection is larger, the actual selection should be as small as possible to improve the measurement accuracy. The main reason for this is the same. Questions 1, 3, and 6 are related. For example, a vortex pipeline is designed for use by several equipment. Because some of the equipment is not used, the actual actual flow is reduced. The actual design results in too large an original design, which is equivalent to an increase in measurable flow. The lower limit, when the process pipe has a small flow rate, the indication cannot be guaranteed. When the flow rate is large, it can be used, because it is sometimes too difficult to re-engineer. Changes in process conditions are only temporary. The re-tuning of the parameters can be combined to improve the 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 the problem 1. For example, the straight pipe section in front of the sensor is obviously insufficient. Since the FIC203 is not used for measurement, it is only used for control, so the current accuracy can be used equivalent to the downgrade.
Vortex flowmeter analysis and solution
6. The connection problem between the secondary instrument and the subsequent instrument. Due to the problem of the subsequent instrument or the maintenance of the subsequent instrument, the mA output circuit of the secondary instrument is interrupted. For this type of secondary instrument, this part is mainly related to the problem 2. Especially for the subsequent recorders, in the case that the recorder cannot be repaired for a long time, it is necessary to pay attention to shorting the output of the secondary meter.
7. The circuit always has no indication due to the failure of the secondary instrument flat-axle cable. Due to long-term operation, coupled with the influence of dust, the flat-axle cable is faulty, and the problem can be solved by cleaning or replacing the flat-axis cable.
8. For the problem 7, the main problem is that the secondary instrument shows that the fixing screw of the meter head is loose, causing the head to sink, the pointer and the case friction are large, the movement is not working, and the problem is solved by adjusting the meter head and re-fixing.
9. Use environmental issues. In particular, the sensor part installed in the well is affected by the humidity of the environment, which causes the circuit board to be damp. This part is mainly related to questions 2 and 2. Through the corresponding technical improvement measures, the sensor part with large humidity is re-separated from the probe part and the conversion part, and the separate type sensor is used. Therefore, the working environment is good, and the instrument has been running well.
10. Due to the poor adjustment of the site, or due to the actual situation after the adjustment. Due to the on-site vibration and noise balance adjustment and sensitivity adjustment is not good. Or because of the re-allocation of the situation after a period of operation after the adjustment, causing the indication problem, this part of the reason is mainly related to questions 4 and 5. Use an oscilloscope, plus the combined process operation, and re-adjust.