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Your location: Home > Related Articles > Interpreting Common Vortex Flowmeter Faults

Interpreting Common Vortex Flowmeter Faults

Author:QINSUN Released in:2023-06 Click:138

As a flowmeter, the vortex flowmeter will also have failures due to some factors under qualified quality condition. What are the common vortex flow meter failures?

1. There is signal output when there is no flow

The analysis of the reason is that the shielding or grounding of the instrument cable causes interference signals; there is strong interference from electrical equipment or power lines around the instrument; the pipe is strongly vibrated. The solution is to reinforce the shielding of the conductor wires to ensure that the lines are well grounded; move the instrument away from sources of interference; skip the trigger level or reduce the shock. 

2. The indication value deviation is too large and the repeatability is too large

The reason analysis is that the primary component vortex generator is damaged; the length of the sections of cstraight upstream and downstream channeling is not sufficient; the instrument constant K Only the setting is incorrect; the probe is seriously polluted; the disturbance of the fluid in the pipeline is too great. The solution is to replace the vortex generator; change installation location; re-measure the calibration to obtain the correct K constant of the instrument; clean the probe; change the installation location and increase the inlet pressure. 

3. There is no display on the secondary instrument after power on

The reason analysis is that the power supply wiring is incorrect or the power is disconnected; the wiring voltage is over 220V and the electric oven is burnt out; Voltage does not match; the sensor is faulty or the amplifier board is faulty; the flow in the channel is too low or there is no flow in the pipeline. The solution is to check theline and connect it correctly; if it burns out, look for damaged parts and replace the original parts; provide electrical power as needed; replace defective parts of the secondary instrument; adjust the flow rate of the pipeline.

4. Flow rate lower limit expansion is limited

Choose a flow rate display integrator which can set the flow rate compensation correction coefficient and realize the expansion of the lower rate limit through software programming. Taking the triangular columnar vortex generator as an example, the Reynolds number ranges from 2×104 to 7×106. In order to extend the lower limit of the flow rate to 5×103, it should be corrected when measuring a small flow. According to the theoretical compensation correction coefficient in the range of Reynolds number 5 × 103 ~ 2 × 104, the lower limit of the flow rate is extended, and the flow measurement error is compensated.

5.The remote transmission signal output is abnormal

The reason analysis is that if it is frequency or pulse signal output, the receiving circuit is compatible with output circuit; if it is current output (4-20)mA, the flow setting range does not correspond to the output current one by one. The solution is to connect external electrical components (such as resistors with some resistance in series), so that the output and input circuits are well matched; when setting the parameters, the upper and lower flow limit values ​​correspond to 4mA and 20mA one by one.

6. Throughput is inaccurate, which is quite different from process parameters

Analysis of the reason is that process parameters are entered incorrectly; the measuring range of the instrument does not match the actual flow requirements. The solution is: enterSet the instrument parameters correctly; tune the process or select an instrument suitable for the actual flow range.

7. The instrument constant K changes with the change of medium used

When the vortex flow sensor is used to measure liquid flow, water must be used to calibrate the instrument constant K value. When steaming, gas must be used Calibration instrument constant K value. Although in principle, the instrument constant K value does not have not related to the properties of the measured medium, but due to the sensor processing technology, there are differences between manufacturers, and the K value corresponding to different fluids will have some differences. Therefore, when using different media, it should be calibrated with the same media to obtain the constant K value of the instrument. At the same time, when the temperature of the mediumused is higher than 150°C, the value of the constant K of the instrument must also be corrected.

8. After the instrument has been used for a period of time, the error deviates from the normal range

Since the industrial fluid often contains impurities, the sensor should be cleaned within the specified time according to the specific situation.