Industry new

Description of the main faults during the commissioning period of the electromagnetic flowmeter

Electromagnetic flowmeter debugging Expectation faults generally appear in the stage of installation and commissioning of the instrument. Once excluded, it will not appear again under the same conditions in the future. Common commissioning failures are often caused by improper installation, environmental disturbances, and fluid characteristics.

1. Environmental aspects
Usually mainly due to pipeline stray current interference, space strong electromagnetic wave interference, large motor magnetic field interference. Pipe stray current interference usually takes good single grounding protection to get satisfactory results, but if you encounter strong stray current (such as electrolysis shop piping, sometimes the peak potential Vpp induced on the two electrodes can be as high as 1V), still Additional measures and insulation of the flow sensor and piping are required. Space electromagnetic interference is typically introduced via a signal cable and is typically protected by a single or multiple layers of shielding.
2. Installation aspects
Usually the fault caused by the incorrect installation position of the electromagnetic flow sensor, such as installing the sensor at the highest point of the pipe that is easy to accumulate gas; or installing it on the vertical pipe from top to bottom, may appear empty; or after the sensor Back pressure, the fluid is directly discharged into the atmosphere to form a non-full tube inside the measuring tube.
3. Fluid aspects
The evenly distributed microbubbles in the liquid to be tested usually do not affect the normal operation of the electromagnetic flowmeter, but as the bubbles increase, the output signal of the meter fluctuates. If the bubbles are large enough to cover the entire electrode surface, the bubble flow The over-electrode causes an instantaneous disconnection of the electrode loop and a greater fluctuation in the output signal. When the low-frequency square-wave excited electromagnetic flowmeter measures the solid content of too much slurry, it will also generate slurry noise, which will cause the output signal to fluctuate. When measuring mixed media, if the flow sensor is measured before the mixing is not uniform, the output signal will also fluctuate. Improper matching of the electrode material and the measured medium will also affect normal measurement due to chemical action or polarization. The electrode material should be properly selected according to the instrument selection or related manual.

PREVIOUS：Professional introduction to the basic methodNEXT：Introduction to the advantages and disadvanta