Choice of protection level
The protection level of the electromagnetic flowmeter should be selected according to the actual situation. If the sensor is required to be installed below the ground and is often flooded, IP68 should be selected. If the sensor is installed above the ground, IP65 and IP67 should be selected. In any case, the display area of ??the electromagnetic flowmeter cannot be used with water or enter the water, which may cause damage to the electromagnetic flowmeter. As a chemical company, the workshop produces high humidity, but IP65 (IP65 is a water-proof type. The electromagnetic flowmeter sensor housing allows the faucet to spray water from the sensor in any direction of the sensor of the electromagnetic flowmeter. The pressure of the water spray is 30Kpa, the water output It is 12.5L/S and the distance is 3 meters.) The electromagnetic flowmeter of the protection grade fully meets the requirements of on-site measurement.
Choice of connection method
Electromagnetic flowmeters have threaded connections, flanged connections, clamps, etc. In the chemical industry, flange-connected electromagnetic flowmeters are generally used. The selection must be consistent with the process-flange engineering pressure and standards.
Conclusion, with the maturity of the domestic instrument industry, chemical companies such as lithium carbonate, boric acid and potash will also enter the market in line with the domestic market. As an important industrial flow measuring instrument, electromagnetic flowmeter should play its role in DCS control. The right selection is especially important to provide accurate measurement data, reduce labor costs and increase production efficiency.
Second, the compressed air vortex flowmeter installation steps
1. The special flanges to be equipped are welded to the upstream and downstream straight pipe sections respectively, so that the inner diameters of the special flange and the straight pipe section are strictly vertical and concentric.
2. Install the sensor clip on the upper and lower straight pipe sections welded with special flanges and fasten them with bolts. The upstream and downstream straight sections should be kept concentric with the sensor.
3. It should be noted that the flow direction of the sensor should be consistent with the flow direction of the fluid in the pipeline.
Third, special attention should be paid when installing compressed air vortex flowmeter
1. When welding special flanges and straight pipe sections, the sensor should be removed and the sensor welding flange must not be carried.
2. Before the sensor is installed, the sealing ring must be placed in the groove of the flange.
3. The pressure point and temperature measurement point should be at the 3DN~5DN and 6N~8DN downstream of the sensor.
4. When the high temperature pipeline is insulated, do not wrap the sensor to avoid damage.
5. The cable connecting the vortex flowmeter should be as far away as possible from the interference of strong electromagnetic fields. It is absolutely not allowed to lay with high voltage cables. The shielded cable should be as short as possible, the maximum length should not exceed 500 meters, and should not be coiled to reduce the distributed inductance.
Test equipment: one 500MΩ insulation resistance tester, one multimeter.
(1) When the pipeline is filled with medium, measure the resistance between terminals A, B and C with a multimeter. The resistance between A-C and B-C should be equal. If the difference is more than 1 time, there may be leakage of the electrode, condensation on the outer wall of the measuring tube or the junction box.
(2) In the case of lining drying, measure the insulation resistance between A-C and B-C with MΩ meter (should be greater than 200MΩ). Then use a multimeter to measure the resistance of the two electrodes in terminals A and B and the measuring tube (should be in short-circuit communication). If the insulation resistance is small, indicating that the electrode is leaking, the entire flowmeter should be returned to the factory for repair. If the insulation is reduced but there is still more than 50 MΩ and the inspection result of step (1) is normal, the outer wall of the measuring tube may be damp, and the inside of the outer casing may be dried by a hot air blower.
(3) Use a multimeter to measure the resistance between X and Y. If it exceeds 200 Ω, the excitation coil and its lead wire may be open or poorly connected. Remove the terminal block check.
(4) Check the insulation resistance between X, Y and C, which should be above 200 MΩ. If it is lowered, dry the inside of the casing with hot air. In actual operation, the decrease in coil insulation will result in increased measurement error and unstable instrument output signal.
(5) If it is determined that the sensor is faulty, please contact the manufacturer of the electromagnetic flowmeter. The general site cannot be solved and needs to be repaired by the manufacturer.