Considerations for selecting and using electromagnetic flowmeters
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Precautions for the selection and use of electromagnetic flowmeters (I) Advantages: 1. Suitable for measuring the flow rate of corrosive media such as acids and alkalis; an appropriate lining and electrode material can be selected； 2. Low compression loss, wide range ratio of 50:1 ； 3. Slurry-type media, solid-liquid two-phase media ； 4. Insertion-type electromagnetic flowmeters can be opened under pressure (II). Disadvantages: 1. Conductivity ≥5µs/cm ； 2. Flow rate range: 0.5 m/s~10 m/s (flow rate in cubic meters per hour; the pipe diameter needs to be reduced) ； 3. Flow rate meters that measure volumetric flow; a fixed density can be entered, and this value is used to convert the measurement to a mass flow rate for display. However, when the density changes significantly, the accuracy of the mass flow rate display decreases ； 4. It is not suitable for use with sodium hydroxide solution, as its high permeability leads to leakage at the electrodes, causing corrosion and rendering the coil unusable ； 5. Not suitable for use in a vacuum environment; it can damage the lining ； 6. Not suitable for use in high-temperature environments; the lining is damaged ； 7. Devices such as frequency converters, transformers, and high-voltage motors, which generate strong interference, should not be used in these locations ； 8. A straight pipe section is required, 5D in front and 3D behind; in cases with complex piping layouts, 10D in front and 5D behind ； 9. Gas and liquid phases must not coexist ； (III) Installation precautions: 1. The flange surface and lining material must be protected with covers ； 2. Use a corresponding cushion in conjunction with the lining material: asbestos ； Polytetrafluoroethylene ； Rubber, etc ； 3. Installation direction is vertically upward ； 4. Do not install at the highest point of the pipeline ； 5. The pipeline behind the flow meter is raised, allowing flow in an overflow manner ； 6. The grounding ring and grounding wire are in good condition ； 7. Piping uses supports and hangers to absorb vibrations ； 8. The power supply level is correct ； 9. Sealing of the input ports and junction boxes to prevent moisture and water ingress: A decrease in insulation between the coil, shielding, and housing can severely affect the signal quality ； 10. Before the instrument is put into use, save the resistance values: 1) the resistance of the coil; 2) the resistance between the electrodes when the medium flows through normally. These values are used for comparison during subsequent fault diagnosis, such as in cases of coil short circuits or open circuits ； Scaling at the electrodes, etc. 11. When necessary, ensure that zero-point calibration can be performed with the medium filling the pipe, zero flow rate, and no stress on the installation ； 2023.9.10
Based on your description, the considerations for selecting and using electromagnetic flowmeters are as follows: Considerations for selection: 1. Choose appropriate lining materials and electrode materials according to the properties of the medium. 2. Ensure the conductivity of the medium is ≥5μs/cm. 3. Select the appropriate electromagnetic flowmeter model based on the flow rate range. 4. Electromagnetic flowmeters are not suitable for situations where a liquid and gas phase coexist. Precautions for use: 1. Use protective covers to safeguard the flange surface and lining material during installation. 2. Use appropriate cushions to protect the lining materials, such as asbestos, polytetrafluoroethylene, rubber, etc. 3. During installation, the flow direction should be vertically upward; it should not be installed at the highest point of the pipeline. 4. The pipeline behind the flow meter should be raised to allow overflow flow. 5. Ensure that the grounding ring and grounding wire are in good condition. 6. Use supports and hangers to absorb pipeline vibrations. 7. Check whether the power level is correct. 8. Ensure that the inlet and junction boxes are sealed to prevent moisture and water ingress, thereby avoiding interference with signal transmission. 9. Before the instrument is put into use, save the resistance value for use in troubleshooting later on. 10. If necessary, a zero-point calibration can be performed, ensuring it is carried out with the medium filling the tube, zero flow rate, and no stress. I hope the above information will be helpful to you. .