In order to make the electromagnetic flowmeter work stably and reliably, the following aspects should be noted when selecting the installation location:
1. Try to avoid ferromagnetic objects and equipment with strong electromagnetic fields (large motors, large transformers, etc.) to prevent the magnetic field from affecting the working magnetic field and flow signal of the sensor.
2. It should be installed in a dry and ventilated place to avoid sun and rain. The ambient temperature should be -20~+60°C, and the relative humidity is less than 85%.
3. There should be plenty of space around the flowmeter for easy installation and maintenance.
The measurement principle of the electromagnetic flowmeter does not depend on the characteristics of the flow. If there is a certain turbulence and vortex in the pipeline, it will be generated in the non-measurement zone (such as elbow, tangential current limit or half-opening shut-off valve upstream). Nothing.
If steady-state eddy currents in the measurement zone affect the stability of the measurement and the accuracy of the measurement, then some measures should be taken to stabilize the flow rate distribution:
a.increase the length of the straight pipe before and after; b. use a flow stabilizer; c. reduce the cross section of the measuring point.
Gas turbine flowmeter and screwing vortex flowmeter measurement difference
Keywords: gas turbine flowmeter, Tianxin gas turbine flowmeter, gas gas turbine flowmeter
First, the characteristics of gas turbine flowmeter and spiral vortex flowmeter
Gas turbine flowmeter and screwing vortex flowmeter are the main gas metering instruments in China. In foreign countries, almost no one uses gas to swirl into the vortex flow meter. At present, there are certain applications in the domestic vortex flowmeter. In terms of standard conditions. The international standard ISO9551 promulgated by the International Organization for Standardization and the international recommendations R6, R32 promulgated by the International Organization of Legal Metrology (OIML) have corresponding national standards and regulations in China and developed countries. The above documents guarantee the authority of gas turbine flowmeters in gas metering. Sex. Gas-introducing vortex flowmeters have not yet established relevant standards. It is difficult to guarantee the authority of the flow meter in gas metering. At present, in domestic flow meters for gas measurement, gas turbine flowmeters dominate, and the vortex flowmeters also have a certain market. The use of the two is similar, and users often have doubts about the choice of the two.
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.