Reasons for large reading error of ultrasonic open channel flowmeter
Open channel flowmeter can be used in harsh environments such as sewage treatment, urban waterway and enterprise wastewater discharge. The open channel flowmeter reflects that the reading is incorrect and the error is very large. What's the matter? Well, let's analyze the reasons.
1 . The sediment installed at the top and bottom of the horizontal piping of the ultrasonic flowmeter sensor interferes with the ultrasonic signal. Solution: install the sensor on both sides of the pipe.
2 . The ultrasonic flowmeter sensor is installed on the piping with water flowing downward, and the pipe is not filled with fluid. Solution: install the sensor on the fluid filled section.
3 . There are devices that make the flow state change violently, such as venturi, orifice, vortex flow meter, turbine flow meter or partially closed valves, which are just within the transmitting and receiving range of the sensor, so that the read value is incorrect. Solution: set the sensor away from the above device, move the upstream of the sensor to the above device 30d, and move the downstream to the above device 10d or the upstream of the above device.
4 . The input pipe diameter of ultrasonic flowmeter is inconsistent with the inner diameter of piping. Solution: modify the pipe diameter to match.
The above is the cause analysis of large reading error of open channel flowmeter. In order to avoid similar problems, the following points should be paid attention to during setting.
1 . It is recommended to connect the earth. That is, the - end of 4 ~ 20mA or - end of XPS is connected to the earth.
2 . Please pay attention to prevent ponding in the wire and cable protection pipe of open channel flowmeter.
3 . The instrument itself has lightning arrester parts, but when the instrument is used in Thunderstorm areas, it is recommended to set special lightning protection devices at the inlet and outlet ends of the instrument as far as possible.
4 . Ultrasonic open channel flowmeter is used in hot and cold places, that is, when the ambient temperature may exceed the working requirements of the instrument, it is recommended to set high and low temperature devices around the liquid level gauge.