The Spheriseal® was invented to allow a mechanical seal to be mounted on a welded pad of a pressure vessel so that the mechanical seal could be aligned with the shaft.  The Spheriseal® allows the hole to be "moved or tilted." 

Because of these features, Spheriseals® allow the use of precision shaft seals with vessel openings which are "as welded". 

The Spheriseal is available as a separate module, or it can be designed into another item such as a packing gland.