Views:0 Author:Site Editor Publish Time: 2021-08-26 Origin:Site
A certain sewage treatment plant in hefei city Anhui province in china:The data of DN600 meter’s head is shaking electromagnetic flowmeter The same phenomenon still occurs after the pump is restarted.
Upon receiving feedback from the customer, the Anretang technical team immediately went to the customer site to examine and analyze the faults:
The electromagnetic flowmeter was detected in the field by ARTang engineer and found that the electromagnetic flowmeter was stable at around 800 m3. The resistance value of the electromagnetic flowmeter was normal when use a multimeter to check. After the pump was restarted again, the dispalys of the screen was found to fluctuate at the range of 800-2400 m3. Then , ARTang engineer started the other three pumps and found that the flowmeter iwas stable at 2400m3. Determined that the fluctuations was caused by bubbles in the pipes.
Install exhaust valves in the pipeline to exhaust bubbles completely.
After installation of exhaust valve, the output data of electromagnetic flowmeter head is stable and running well.
1. If the bubbles inside the measured pipe are caused by the improper installation position of the electromagnetic flowmeter, e.g. the electromagnetic flowmeter is installed at the high point of the pipe (height > 5 m) ,and the residual gas or outside inhaled air will cause the screen signal beat , the measurement error due to the bubble problem can be solved by changing the installation position of the electromagnetic flowmeter, e.g. the electromagnetic flowmeter is installed at the lowest point of the pipeline or install instruments on the U-type pipe.
2. If the calibre of the electromagnetic flowmeter is large or it is not convenient to replace the installation position of the electromagnetic flowmeter, the collection and exhaust valves can be installed upstream of the electromagnetic flowmeter; According to professional research ,a electromagnetic flowmeter with large-calibre can display signal jumps due to bubbles problems, the jumping range is 20%-50%;and the measurement can be restored to normal basically after installing the exhaust valve and the collection package.