A. Unstable readings and drastic changes
Factor analysis: The pipeline of the ultrasonic flow sensor of the equipment oscillates greatly or there is a modified flow equipment (such as the flow meter equipment downstream of the regulating valve, pump, and shrinking orifice).
Solution: Refit the flow sensor in a place far away from the source of oscillation or move it to the upstream of the modified flow state equipment.
B. Inaccurate readings and large errors
Factor analysis:
1. The ultrasonic flowmeter sensor is installed on the top and bottom of the horizontal pipeline. The sediment disturbs the ultrasonic signal. Solution: Install the sensor on both sides of the pipeline.
2. The ultrasonic flowmeter sensor is installed on the pipe where the water flows downward, and the pipe is not filled with fluid. Solution: Install the sensor on the pipe section filled with fluid.
3. There are equipments that make the flow state violently shake, such as: venturi, orifice, vortex flowmeter, turbine flowmeter or some closed valves, which are just within the scale of the transmitter and reception of the sensor, making the readings inaccurate. Solution: Install the sensor in a place far away from the above-mentioned equipment, the upstream of the sensor is 30D from the above-mentioned equipment, and the downstream distance is 10D from the above-mentioned equipment or move to the upstream of the above-mentioned equipment.
4. The input pipe diameter of the ultrasonic flowmeter does not match the inner diameter of the pipe. Solution: Correct the pipe diameter to match it.
C. The sensor is good, but the flow rate is low or there is no flow rate
Factor analysis:
1. Because the paint and rust outside the pipeline have not been removed. Solution: remove the pipes and equipment sensors from scratch.
2. The pipeline surface is uneven or the ultrasonic flowmeter equipment is at the welding seam. Solution: grind the pipe flat or away from the weld.
3. The roundness of the pipe is not good, the inner and outer surfaces are not lubricated, and there is pipe lining type fouling. If the pipe is a cast iron pipe, this may be the case. Solution: select steel pipes and other internal and external lubrication pipe materials or linings.
4. The measured medium is pure or solid suspended matter is too low. Solution: Use other suitable appearances.
5. Sensor equipment on the fiberglass pipe.
Solution: remove the glass fiber.
6. If the sensor device is on the casing, it will weaken the ultrasonic signal. Solution: Move the sensor to the pipe section without casing.
7. The sensor is not well coupled with the pipeline, and there are gaps or bubbles on the coupling surface. Solution: re-equip the couplant.
D. When the control valve is somewhat closed or the flow rate drops, the reading will increase instead
Factor analysis: The sensor is installed too close to the downstream of the control valve. When some valves are closed, the practice of flow meter measurement is to control the valve to reduce the flow rate and increase the flow rate. The flow rate increases due to the decrease in the caliber. Solution: Move the sensor away from the control valve, the upstream of the sensor is 30D from the control valve or move the sensor to the upstream of the control valve by 5D.
E. The ultrasonic flowmeter works normally, but the ultrasonic flowmeter no longer measures the flow
Factor analysis:
1. The tested medium has changed. Solution: Change the measurement method.
2. The measured medium is gasified due to high temperature. Solution: Cool down
3. The temperature of the measured medium exceeds the limit temperature of the sensor. Solution: Cool down
4. The couplant under the sensor is aged or consumed. Solution: reapply coupling agent
5. Because of high-frequency interference, the appearance exceeds its filter value. Solution: stay away from the source of disturbance. 6. Data loss in the computer. Solution: input the accurate parameters from the beginning
7. The accounting machine crashes. Solution: restart the computer from the beginning