Since the spring is used for pressurizing in the live loading method, maintaining the packing tightening force for a long time will assure more stabilized sealing performance as compared with the conventional type seal unit.
For construction, the live seal unit comes in the following three types, depending on the application condition.
- Single gland type
- Double gland type
- Floating gland type
◆Improved follow-up performance against shaft run-out
Designing the seal unit to "Double gland type" or "Floating gland type" will enhance the follow-up performance against shaft run-out.
It is possible to control the tightening force by zeroing the clearance between collar(spring cover) and packing retainer.
Since it is possible to check the decrease in tightening force by observing the clearance between collar and packing retainer, it becomes possible to know the time for re-tightening, and to execute the visible control.
The adoption of live loading method(spring pressurizing method) serves to realize the followings: - to maintain the packing tightening force for a long time - to reduce the leakage - to reduce the maintenance - to prolong the service life of seal