Sealing Sub-System Fluid Test
Dennis Beatty
Tested:
Preliminary water tightness and motion tests for the shaft-mechanical seal-seal flange-vinyl boot interface.
How:
The sealing system will be placed with the tank wall opening facing upward and water will be added until the boot is full. Visual inspection of leakage will follow as well as rough manual movement, which includes: rotational, angular and translational movement of the shaft. Proof being shown through pictures and a video showing movement.
Results:
Leakage – The vinyl boot itself showed no signs of leaking water, the same can be said for the mechanical seal and shaft connection and the mechanical seal to seal flange interface. Leaking occurred at the flushing port of the mechanical seal itself. It also occurred at the interface between seal flange and vinyl boot.
Movement – Rotation of the shaft was successful and provided no further leakage when rotated. Angular movement and translational movement were also successful, full range of movement in that respect is available.
Action Items:
Leakage – In order to prevent water from seeping from the flushing port, a socket head cap screw will be threaded into the port. A new type of gasket will be needed for the seal flange-vinyl boot interface, and if it is failing here, also for the tank wall-vinyl boot interface. It is believed that the gasket material is both a wet sealing gasket and is also a high pressure gasket material. It is rigid and does not allow for deformation to fill in the ridges of the vinyl boot material. The pressure in the boot while attached to the tank will be at a max of roughly 5 psi, so these leaks need to be taken care of if they are to be acceptable later.
Movement – While all movement is available, the boot material behaves unexpectedly and is at risk for coming in contact with the rotating shaft. Once connected to a tank full of water and testing pressure is reached, this will be looked at again. Recommendation if it is still a problem is for either a sheath tube around the shaft within the boot to protect it or brackets mounted to the tank flange and seal flange that hold the boot up. The latter however is not a guarantee and it would be in the best interest to investigate a sheath.