This type of flushing plan is used external source as flushing/cooling medium to the mechanical seal. It is very important to ensure that the medium will not downgrade the quality of pumping fluid and must continously supply to the mechanical seal eventhough the pump in a stop condition, this is very important to protect any vapour or fluid enter to the mechanical seal.
A certain minimum and maximum pressure of seal cooling medium/source shall be maintained based on the vendor recommendation and hydraulic analysis adjustment. so it will achieve the objective of Plan 32 to have extended life time and reliable mechanical seal.
However, as optimization effort to save the external source. It may also modify the system on the seal cooling medium supply by installing the on/off valve, so it will be supplied only in a certain condition such as prior to start, normal running and a few seconds after stop the pump.
This type of flushing system is preferred to be selected if the main fluid is corrosive or not compactable to be used as cooling medium of mechanical seal.
