Flow meter issues
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There is an electromagnetic flow meter with a DN450 rating in the plant. Water is pumped into the 450-sized pipeline through 5 identical pumps via 100-mm diameter pipes. The flow meter is located about 6 meters away from the nearest pump; one end of the pipeline is sealed, and the outlet end of the pipeline is raised to ensure proper storage. The capacity of each pump is 100 cubic meters. Flow occurs when one pump is in operation, but why is there no flow when two pumps are used?
The signal of the electromagnetic flowmeter is in the millivolt range; first, check whether the grounding of the electromagnetic flowmeter is proper.
What does it mean that the other end of the pipe is sealed?
It would be best to have a piping diagram, as it makes analysis easier
Won’t there be any flow even if 2 water pumps are turned on arbitrarily? Is it okay to run 3 units?
Modern electromagnetic flowmeters generally use alternating magnetic fields, which allow them to effectively avoid interference from external static electromagnetic fields even in the absence of grounding; therefore, any lack of readings is likely not related to interference. If possible, the original poster should provide a piping diagram of the site; I think it’s caused by the flow pattern of the fluid.
Let’s play a riddle game. One end of the pipe is closed. When the first pump is started, fluid flows in, so there is flow. When the second pump is started, no more fluid can flow through the system; since the fluid doesn’t move, there is no flow either