Xiaobai is asking: when turning off a centrifugal pump, should the return valve be opened?
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For the centrifugal pumps used in our factory to produce methanol, with an outlet pressure of 1 Mpa (gauge pressure), should we turn on the reflux valve first before closing the outlet valve when shutting down the pump? (During normal operation, the return flow is basically completely shut off.) I seek guidance from experienced professionals and would like to know the reasons for this
A pressure of 1MP is not high; there is no need to activate the reflux function – simply close the outlet and then stop the pump
Think differently: what if the pipeline doesn’t have a return pipe? :lol
What I want to know is why a recirculation system was designed into this pump? So, following normal logic, it should be 1: turned off during normal operation, and turned on under abnormal conditions, such as during start-up or shutdown processes. 2 As for whether it needs to be turned off or not, it depends on the speed of this pump; if it is a high-speed pump, then the return flow still needs to be enabled. 3. For a regular pump, it is necessary to take into account the properties of the medium; if it is methanol, which vaporizes more easily due to its physical properties, it is recommended to enable reflux, as this practice is beneficial for the pump. Of course, if the properties of the medium permit it, it may not be necessary to turn off the reflux.
There’s no need to close it; the check valve is generally used for unloading