PUMP OUT VANES P044
They were put there to:
- Reduce stuffing box pressure.
- Reduce axial shaft thrust
- Make the flushing of packing more effective.
If the impeller has been adjusted too close to the back plate the pump out vanes can cause a vacuum to occur in the stuffing box any time you are using mechanical seals.
This mistake can happen if the mechanic has been taught to adjust the open impeller towards the back plate in a Duriron (Flowserve) pump and then makes the same adjustment in a Goulds pump that should have the impeller adjusted forward to the volute.