How to determine if a vortex flowmeter is affected by vibration interference?

Judging Vibration Interference in Vortex Flow Meters‌

To determine whether a vortex flow meter is affected by vibration interference, a comprehensive analysis must be conducted by combining signal anomalies, measurement errors, and pipeline vibration sources. The following key indicators can be used for identification:

1. Signal Anomaly Characteristics‌

False Signal Output Without Flow‌

If the flow meter displays an instantaneous flow rate when there is no medium flowing in the pipeline, it may be due to vibrations causing the piezoelectric sensor to trigger erroneously. If the signal does not return to zero after closing the valve in intermittent operation, it is necessary to check the intensity of pipeline vibrations and potential electromagnetic interference.

Signal Fluctuations or Distortion‌

Vibrations may cause irregular, fluctuating, or high-frequency noise in the signal output. It is essential to investigate whether pipeline vibrations exceed the instrument's vibration resistance (e.g., under 20Hz vibrations, the error of a standard vortex flow meter can reach 3.2%).

2. Measurement Error Manifestations‌

Failure in Low-Flow Measurement‌

If the meter resets to zero when the flow rate drops below a certain threshold, it may be due to vibration interference masking small signals or reducing sensitivity.

Increased Error at High Flow Rates‌

A significant increase in error at higher flow rates may result from the superposition of vibrations and the distortion of vortex shedding frequency.

3. Correlation with Pipeline Vibration Sources‌

Vibration Transmission at Installation Points‌

If the flow meter is installed near vibration sources such as pumps, valves, or elbows (e.g., within 5 pipe diameters of a pump outlet), the mechanical vibration intensity should be checked first.

Pulsating Flow Interference‌

Pressure pulsations from equipment like reciprocating pumps or roots blowers can transmit through the pipeline and generate false signals in the flow meter.

4. Comprehensive Diagnostic Methods‌

Vibration Testing‌

Use a vibration sensor to measure the frequency and amplitude of pipeline vibrations, ensuring they remain within the allowable range of the flow meter (e.g., ≤50Hz).

Signal Analysis‌

Observe the output signal waveform with an oscilloscope. If interference pulses synchronized with the vibration frequency are detected, vibration interference can be confirmed.

Isolation Testing‌

Temporarily connect the flow meter using a flexible hose. If signal stability improves, it indicates rigid vibration transmission at the original installation point.

Note:‌ If vibration issues cannot be resolved by adjusting sensitivity or installation, consider upgrading to a smart vortex flow meter with digital filtering to effectively suppress vibration noise.