Several Abnormal Phenomena Handling Methods of Compressed Air Flow Meter During Use

2022-06-09
 Several Abnormal Phenomena Handling Methods of Compressed Air Flow Meter During Use

Phenomenon

1. There is no indication and no output signal after power-on.
   1) The totalizer has no 24V car output, and the totalizer should be checked;
   2) The wiring is incorrect or disconnected. If the polarity of the power supply is reversed, the wiring should be corrected;
   3) If the sensor of the air vortex flowmeter is broken or the converter is broken, it should be repaired or replaced;
   4) There is no flow in the pipeline or the flow is too small, and the inner diameter of the pipeline where the meter is installed should be reduced. Phenomenon

2. There is signal output during flow
   1) The lead wire of the instrument is poorly shielded or grounded, and 50Hz interference is introduced. The shielding or grounding device should be strengthened to eliminate the 50Hz interference;
   2) There are strong electrical equipment or power lines nearby, so that the instrument and transmission lines are far away from interference
   3) If there is strong vibration on the pipeline, a shock absorber should be installed, the filter should be strengthened or the sensitivity of the instrument should be reduced. Phenomenon

3. The flow indication value fluctuates greatly
   1) The sensitivity of the meter is adjusted too high, and the sensitivity should be reduced;
   2) The measuring head is seriously contaminated, which changes the frequency of the Karman vortex, so that the measured flow value is quite different from the actual value, and unstable. This situation often occurs, especially in winter due to the low temperature, the tar and naphthalene contained in the gas condense and adhere to the measuring head, so the error caused will reach 20%~30% of the actual value. At this time, the measurement should be cleaned regularly. Head (2~3 times/month in summer, 2~3 times/week in winter);
   3) If the pipeline is affected by vibration, the filter should be strengthened or a shock absorption device should be installed;
   4) The piezoelectric chip is damaged, and the piezoelectric chip can be replaced;
   5) The process fluctuates greatly. Although this is not a fault phenomenon, it will be encountered in normal maintenance work, and it is necessary to take it as a way of thinking in fault analysis.



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