Problem of reverse rotation when a cantilever pump is stopped
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In our plant, there are three centrifugal cantilever pumps operating in parallel, and the check valves used are H71H lift-type wafer check valves. What is the reason for the reverse rotation when one of these pumps stops operating? All check valves have been replaced with new ones. .
I forgot to mention it – it’s a vertical pipe, with water flowing from bottom to top. Can this type of check valve only be installed in horizontal pipes?
If it’s reversed, there must be liquid flowing back. Is there also a crossover valve at the outlet? If not, it must be that the check valve isn’t closed properly
Unless all three new ones are faulty. . And they are not valves from the same factory
If you don’t believe it, there’s nothing I can do. Just trust that something new won’t cause any problems; go and check it out slowly then
In a normal shutdown, pump reversal is caused by a problem with the outlet check valve, which leads to backflow of the fluid and thus pump reversal; I can’t think of any other possible causes. It is recommended to check the check valve
The check valves are new, so there should be no problems, unless all three of them fail
The newly replaced ones may not be able to be shut off completely either