Problems with electromagnetic flowmeters
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Can an electromagnetic flowmeter measure the flow rate of clean water? One of our electromagnetic flowmeters (used to measure the flow rate of lean liquid) is now filled with clean water, yet it shows that the pipe is empty! I went to the site and checked; the grounding wasn’t done, the cables weren’t shielded, and the signal cables and excitation cables weren’t separated. I still think the biggest problem is the conductivity of water. What do you all think?
This post was last edited by again on 2010-3-6 10:48. Should pure water conduct electricity without any problems? Is the water flowing?
The electromagnetic flowmeter can measure water flow without any problems; the installation was simply poor.
It is recommended that you run the long-distance cable across and use a signal tester on-site to check whether the signal can be transmitted
Electromagnetic flowmeters have limitations regarding conductivity; you can check the instrument’s manual for details. If it is pure water, the conductivity may be too low to be measured; the design specifications should include this parameter
The conductivity specification calls for 5 uS/cm; I wonder what the conductivity of pure water is? The installation aspect also requires the contractor to handle it!
The conductivity setting is too low; the empty tube detection chamber determines this value based on conductivity. By setting the conductivity to 5 when an empty tube is detected, the flow rate can be displayed
It’s better to use pure water or some other substance for testing; the conductivity is too low for electromagnetic measurement to work. A float-based method is a viable option, as it is cost-effective and reliable.
Electromagnetic flowmeters are suitable for measuring circulating water; for fresh water, it is recommended to use remote-transmission water meters, which are inexpensive and offer good measurement accuracy.
Electromagnetic flowmeters can be used to measure pure water; our factory uses electromagnetic flowmeters for its domestic water supply. It’s also possible to use a multimeter to check whether the flowmeter is generating a signal output – if not, then the conductivity should be adjusted