The ultrasonic flowmeter may have some failures during daily use. Our production technicians have made a small summary of these failures, the causes of the failures, and the treatment methods:
1. Symptom: Abnormal flow rate display, data changes dramatically
Cause analysis: The sensor is installed in a place with a large vibration in the pipeline or changes the flow device (such as the downstream of a regulating valve, a pump, a reduction orifice)
Solution: Install the sensor away from the vibration source or move it upstream of the fluid change device
2.Symptom: Incorrect reading
Reason analysis: A. The sensor installed on the top and bottom of the horizontal pipe interferes with the ultrasonic signal. B. The sensor is installed on the pipe where the water flows downward, and the pipe is not full of fluid.
Solution: A. Mount the sensor on both sides of the pipe B. Mount the sensor on a fluid-filled pipe section
3.Symptom: Incorrect reading
Reason analysis: A. The device that makes the fluid state fluctuate strongly, such as: venturi, orifice plate, vortex street, turbine or partially closed valve, is in the range of the sensor transmitting and receiving, making the reading inaccurate. B. The input diameter of the flowmeter does not match the inside diameter of the pipeline.
Solution: A. Install the sensor away from the above device, the sensor upstream from the device 30D, downstream from the device 10D or move upstream of the device. B. Modify the pipe diameter to match
4.Symptom: The sensor is good, but the flow rate is low or no flow rate
Cause analysis: A. The paint and rust outside the pipeline have not been removed. B. The pipe surface is uneven or installed at the welding seam. C. The roundness of the pipe is not good, the inner surface is not smooth, and there is pipe-lining fouling. This may happen if the pipe is cast iron. D. The measured medium is too low for pure or solid suspended matter. E. The sensor is installed on the fiberglass pipe. F. The sensor is mounted on the casing, which weakens the ultrasonic signal. G. The sensor is not well coupled to the pipeline, and there are gaps or bubbles in the coupling surface.
Solution: A. Clear the pipeline again and install the sensor. B. Grind the pipe flat or away from the weld. C. Select the place where the inner surface of the pipe, such as steel pipe, is smooth. D. Use other suitable types of instruments. E. Remove the glass fibers. F. Move the sensor to the unpiped pipe section. G. Reinstall the couplant.
5.Failure phenomenon: When the control valve is partially closed or the flow is reduced, the reading will increase.
Reason analysis: The sensor is installed too close to the downstream of the control valve. When the valve is partially closed, the flowmeter actually measures the flow rate of the control valve to reduce the diameter and increase the flow rate. The flow rate increases due to the reduction of the diameter.
Solution: Move the sensor away from the control valve, 30D upstream of the sensor or 5D upstream of the control valve.
6.Failure phenomenon: The flowmeter works normally, and suddenly the flowmeter no longer measures the flow.
Cause analysis: A. The measured medium has changed. B. The measured medium is vaporized due to excessive temperature. C. The temperature of the measured medium exceeds the limit temperature of the sensor. D. The couplant under the sensor is aged or consumed. E. Due to high-frequency interference, the meter exceeds its own filtering value. F. Data in the computer is lost. G. Computer freezes.
Solution: A. Change the measurement method B. Cool down C. Cool down D. Recoat the coupling agent E. Keep away from interference sources F. Re-enter the value G. Restart the computer