The concentrated water discharge valve is always open during reverse osmosis operation, so when the reverse osmosis unit stops running, if the highest point of the discharge pipe is lower than the highest point of the pressure vessel, a "siphon" phenomenon will occur.
The water in the pressure vessel will flow out of the reverse osmosis device through the concentrated water discharge pipe due to its own weight, and air will be mixed into the pressure vessel.
One reason is that it is easy to cause water hammer, and the other is that oxygen in the air will oxidize the reverse osmosis membrane element more or less when it is shut down, which will affect the service life of the membrane element.
