做为新型的流量计仪表，用量正在逐渐增加。 As a new type of flow meter, the ultrasonic flow meter is gradually increasing its usage. Because of the wide use, many technicians have been exposed to the installation and commissioning of ultrasonic flowmeters. There are often several failures in this
Performance, has been plagued by many technical personnel, and now analyzes some failure phenomena as follows:
I. Failure phenomenon: Unstable reading changes drastically
Cause analysis: The pipeline where the ultrasonic flow sensor is installed has a large vibration or a device that changes the flow pattern (such as a flow meter installed downstream of a regulating valve, a pump, or a reduction orifice)
Solution: Modify the flow sensor away from the source of vibration or move it upstream of the flow changing device
2. Failure phenomenon: Inaccurate reading and large error
1. Ultrasonic flowmeter sensor The sediment installed on the top and bottom of the horizontal pipe interferes with the ultrasonic signal. Solution: Install the sensors on both sides of the pipe.
2. The ultrasonic flowmeter sensor is installed on the pipe where the water flows downward, and the pipe is not full of fluid. Solution: Mount the sensor on a fluid-filled pipe section.
3. There are devices that make strong flow fluctuations, such as: venturi, orifice plate, vortex, turbine, or partially closed valve, which are within the range of the sensor transmitting and receiving, making the reading inaccurate. Solution: Install the sensor
Where it is far away from the device, the sensor is upstream from the device 30D upstream, and downstream from the device 10D or moved upstream of the device.
4. The input pipe diameter of the ultrasonic flowmeter does not match the inner diameter of the pipe. Solution: Modify the pipe diameter to match.
Third, the failure phenomenon: the sensor is good, but the flow rate is low or no flow rate
1. The paint and rust outside the pipeline have not been removed. Solution: Clear the pipeline again and install the sensor.
2. The piping surface is uneven or the ultrasonic flowmeter is installed at the welding seam. Solution: Grind the pipe flat or away from the weld.
3. The roundness of the pipeline is not good, the inner surface is not smooth, and there is pipe-lining fouling. This may happen if the pipe is cast iron. Solution: Choose a place with smooth inner pipe material or lining, such as steel pipes.
4, the measured medium is pure or solid suspended matter is too low. Solution: Choose other types of instruments that are suitable.
5. The sensor is installed on the fiber glass pipe. Solution: Remove the glass fiber.
6, the sensor is installed on the casing, it will weaken the ultrasonic signal. Solution: Move the sensor to the unsleeved pipe section.
7, the sensor is not well coupled with the pipeline, the coupling surface has gaps or bubbles. Workaround: Reinstall the couplant.
Fourth, the 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, and move the sensor 30D upstream of the control valve or move the sensor to the control valve 5D upstream of the control valve.
工作正常，突然超声波流量计不再测量流量了 V. Failure phenomenon: The ultrasonic flowmeter works normally, and suddenly the ultrasonic flowmeter no longer measures the flow.
1. The measured medium changes. 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 coupling agent under the sensor is aged or consumed. Solution: Recoat the coupling agent
5. Due to high-frequency interference, the meter exceeds its own filter value. Solution: stay away from interference sources
6. The data in the computer is lost. Solution: Re-enter the correct parameters
7. The computer freezes. Workaround: restart the computer
The above is a summary of the analysis of ultrasonic flowmeter faults by technical staff of Jinhu Dongxiang based on actual work. It is hoped that all technicians using ultrasonic flowmeters can help.
Nine types of ultrasonic flow meters
1. Plug-in ultrasonic flowmeter: special drilling device can be installed without stopping production. Generally, it is mono measurement. To improve the measurement accuracy, three channels can be selected.
2. Pipe-type ultrasonic flowmeter: It is necessary to cut open the pipeline for installation, but future maintenance can be continued. Choose from mono or tri-channel sensors.
3. Outer clip type ultrasonic flowmeter: can perform fixed and mobile measurement. Use special coupling agent (silicone rubber cured at room temperature or high-temperature long-chain polymer grease) for installation, and it will not damage the pipeline during installation
4, portable ultrasonic flowmeter: portable use, built-in rechargeable lithium battery, suitable for mobile measurement, with magnetic sensors.
5, handheld ultrasonic flowmeter: small size, light weight, built-in rechargeable lithium battery, handheld use, with magnetic sensors.
6. Explosion-proof ultrasonic flowmeter: It is used for the measurement of liquid flow in explosive environments. It is explosion-proof and intrinsically safe. That is, the converter is explosion-proof and the sensor is intrinsically safe.
7. Flow measurement system: It consists of multiple ultrasonic flow meters and system master station. Suitable for centralized measurement of multiple pipelines.
8. Ultrasonic calorimeter: used for heat measurement of heating system.
:采用一节锂电池供电的一体式超声波流量计。 9, battery-powered ultrasonic flowmeter : a lithium battery-powered integrated ultrasonic flowmeter. It is suitable for occasions without mains power supply. One battery can be used for ten years and has various measurement functions.