Abstract: Ultrasonic Flowmeter Failure Analysis Some abnormal phenomena and faults may occur during the use of ultrasonic flowmeters. Some fault phenomena are analyzed as follows:
First, the phenomenon of failure: unstable reading changes violent analysis of the reasons: the installation of ultrasonic flow sensor pipeline vibration or change the flow state of the device (such as flow meters installed in the regulating valve, pump, downflow orifice)
Solution: Change the flow sensor away from the vibration source or move to the upstream of the device to change the flow state. Second, the failure phenomenon: Inaccurate reading, large error analysis:
1. Ultrasonic Flowmeter Sensors The sediments on the top and bottom of horizontal pipes interfere with ultrasonic signals. Solution: Install the sensor on both sides of the pipe.
2. The ultrasonic flowmeter sensor is mounted on the water flow down pipe, and the pipe is not filled with fluid. Solution: Install the sensor on a fluid-filled pipe section.
3. There are devices that make the flow regime strongly fluctuate, such as venturis, orifice plates, vortex streets, turbines, or valves that are partially closed, just within the range that the sensor emits and receives, making the reading inaccurate. Solution: The sensor is mounted away from the device, upstream from the device 30D, downstream from the device 10D or upstream of the device.
4. The input diameter of the ultrasonic flowmeter does not match the internal diameter of the pipe. Solution: Modify the pipe diameter to match it.
Third, the failure phenomenon: the sensor is good, but the flow rate is low or no flow rate analysis:
1, because the paint outside the pipeline, rust is not cleared. Solution: Clear the pipe again and install the sensor.
2. The surface of the pipe surface is uneven or the ultrasonic flowmeter is installed at the welding seam. Solution: Smooth the pipe away from the weld.
3, the pipe roundness is not good, the inner surface is not smooth, there is tube lining scale. This may happen if the pipe is a cast iron pipe. Solution: Select a place where the inner surface of the pipe is smooth or lining.
4. The measured medium is pure or suspended solids are too low. Solution: Select the appropriate type of meter.
5. The sensor is installed on the fiberglass pipe. Solution: Remove the glass fiber.
6, the sensor is installed on the sleeve, it will weaken the ultrasonic signal. Solution: Move the sensor to the unsleeved pipe section.
7. The coupling between the sensor and the pipeline is not good, and the coupling surface has gaps or bubbles. Solution: Reinstall the coupling agent.
Fourth, the phenomenon of failure: when the control valve part of the closed or reduce the flow of reading will increase when the cause of the analysis: the sensor is installed too close to the control valve downstream, when the part of the valve is closed when the actual measurement of the valve is to control the flow rate of reducing the diameter of the valve, Due to the narrower diameter, the flow rate increased.
Solution: Move the sensor away from the control valve, the sensor upstream from the control valve 30D or the sensor into the control valve upstream from the control valve 5D.
V. Symptoms: The ultrasonic flowmeter works normally and suddenly the ultrasonic flowmeter no longer measures the flow. Cause Analysis:
1. The measured medium changes.
Solution: Change the measurement method.
2. The measured medium is gasified due to excessive temperature. Solution: Cooling 3, the temperature of the measured medium exceeds the sensor's limit temperature. Solution: Cooling 4. The couplant below the sensor is aging or depleted. Solution: re-coating the coupling agent 5, due to high-frequency interference so that the instrument exceeds its own filter value. Solution: Stay away from sources of interference 6. Data loss within the computer. Solution: Re-enter the correct parameters 7, the computer crashes. Workaround: Restart the computer
First, the phenomenon of failure: unstable reading changes violent analysis of the reasons: the installation of ultrasonic flow sensor pipeline vibration or change the flow state of the device (such as flow meters installed in the regulating valve, pump, downflow orifice)
Solution: Change the flow sensor away from the vibration source or move to the upstream of the device to change the flow state. Second, the failure phenomenon: Inaccurate reading, large error analysis:
1. Ultrasonic Flowmeter Sensors The sediments on the top and bottom of horizontal pipes interfere with ultrasonic signals. Solution: Install the sensor on both sides of the pipe.
2. The ultrasonic flowmeter sensor is mounted on the water flow down pipe, and the pipe is not filled with fluid. Solution: Install the sensor on a fluid-filled pipe section.
3. There are devices that make the flow regime strongly fluctuate, such as venturis, orifice plates, vortex streets, turbines, or valves that are partially closed, just within the range that the sensor emits and receives, making the reading inaccurate. Solution: The sensor is mounted away from the device, upstream from the device 30D, downstream from the device 10D or upstream of the device.
4. The input diameter of the ultrasonic flowmeter does not match the internal diameter of the pipe. Solution: Modify the pipe diameter to match it.
Third, the failure phenomenon: the sensor is good, but the flow rate is low or no flow rate analysis:
1, because the paint outside the pipeline, rust is not cleared. Solution: Clear the pipe again and install the sensor.
2. The surface of the pipe surface is uneven or the ultrasonic flowmeter is installed at the welding seam. Solution: Smooth the pipe away from the weld.
3, the pipe roundness is not good, the inner surface is not smooth, there is tube lining scale. This may happen if the pipe is a cast iron pipe. Solution: Select a place where the inner surface of the pipe is smooth or lining.
4. The measured medium is pure or suspended solids are too low. Solution: Select the appropriate type of meter.
5. The sensor is installed on the fiberglass pipe. Solution: Remove the glass fiber.
6, the sensor is installed on the sleeve, it will weaken the ultrasonic signal. Solution: Move the sensor to the unsleeved pipe section.
7. The coupling between the sensor and the pipeline is not good, and the coupling surface has gaps or bubbles. Solution: Reinstall the coupling agent.
Fourth, the phenomenon of failure: when the control valve part of the closed or reduce the flow of reading will increase when the cause of the analysis: the sensor is installed too close to the control valve downstream, when the part of the valve is closed when the actual measurement of the valve is to control the flow rate of reducing the diameter of the valve, Due to the narrower diameter, the flow rate increased.
Solution: Move the sensor away from the control valve, the sensor upstream from the control valve 30D or the sensor into the control valve upstream from the control valve 5D.
V. Symptoms: The ultrasonic flowmeter works normally and suddenly the ultrasonic flowmeter no longer measures the flow. Cause Analysis:
1. The measured medium changes.
Solution: Change the measurement method.
2. The measured medium is gasified due to excessive temperature. Solution: Cooling 3, the temperature of the measured medium exceeds the sensor's limit temperature. Solution: Cooling 4. The couplant below the sensor is aging or depleted. Solution: re-coating the coupling agent 5, due to high-frequency interference so that the instrument exceeds its own filter value. Solution: Stay away from sources of interference 6. Data loss within the computer. Solution: Re-enter the correct parameters 7, the computer crashes. Workaround: Restart the computer
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