Electromagnetic flowmeter special detection method
Electromagnetic flowmeter is widely used in petroleum, chemical, metallurgy, textile, food, pharmaceutical, papermaking and other industries as well as environmental protection, municipal management, water conservancy construction and other fields. The main components of the sensor are: measuring tube, electrode, excitation coil, iron core and yoke shell. The product is mainly used to measure the volume flow in conductive liquids and slurries in closed pipes, including strong corrosive liquids such as acids, alkalis, and salts. Denim abrasion enzymes, fade enzymes, Denim washing enzymes Sunson Industry Group Co., Ltd , https://www.sunsonchinaenzymes.com
Electromagnetic flowmeter special detection method:
1. Determination of Signal Cable Interference Electromagnetic flowmeter zero point changes in the signal cable due to external electrostatic induction and electromagnetic induction. To determine whether the zero point change is due to signal cable interference potential influences, it is necessary to determine the general scope of the interference and the degree of influence on the electromagnetic flowmeter.
2. Polarization voltage of the electrode Measuring the polarization voltage between the electrode and the liquid will help determine if the zero-point instability or output-swing failure is due to the electrode being contaminated or covered. With a digital multimeter 2V DC gear, measure the polarization voltage between the two electrodes and the ground (the electromagnetic flowmeter can be measured without interruption or blackout). If the two measurements are nearly equal, the electrodes are not contaminated or covered. The magnitude of the polarization voltage is determined by the "electrode potential" of the electrode material and the nature of the liquid. The measured value may be between a few mV and a few hundred mV. Because the two electrodes are actually contaminated during operation, it is not possible to be completely symmetrical, so the voltage across the two electrodes forms an asymmetric common-mode voltage. The asymmetric common-mode voltage becomes a differential mode signal, causing a zero offset.
3, pipe stray current flow discriminating Sometimes looking for spurious interference sources in the flow sensor upstream or downstream, in order to narrow the search, try to reduce or eliminate the effects of stray current interference.
4. Electrode contact resistance Measure the liquid contact resistance value of the electrode spoon to indirectly evaluate the general condition of the surface of the electrode and the liner layer without removing the flow sensor from the pipe, which is helpful for analyzing the cause of the failure.
5, the determination of whether the ground potential electromagnetic flow juice in the normal use of the process, such as the sensor near the motor (force) state changes (such as leakage), the ground potential will change and cause zero changes. Check if there is any influence in this way. Short circuit the converter's working ground C terminal and protective grounding G terminal, and judge whether there is a grounding potential by changing the zero point (or indication value).