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

Stabilized sealing performance
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.

Reduced maintenance
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.

It is necessary to select the proper packing for application condition.
Packing combination example
No. Application Packing combination
1 Resin-base fluid P/#4536 + P/#4526L
2 Food P/#4504 + P/#4536
3 Chemicals P/#4536 + P/#6527L
4 Powder substance + gas P/#6722 + P/#6527L

Construction and features of shaft seal
[Single gland type]
The single gland type is of the simplest construction, in which all the packing are tightened by one packing retainer, however, its follow-up performance against shaft run-out is slightly inferior to the double gland type and floating gland type, as the packing box is fixed to the body.


[Double gland type]
Since the packing for atmosphere and that for inside of equipment are tightened separately, its sealing performance is more enhanced than the seal unit of single gland construction. Besides, the atmospheric side packing follows the shaft run-out within the deformation range of O-ring, as the atmospheric side packing retainer is provided with O-ring.


[Floating gland type]
It is possible for the floating gland type to follow up the shaft run-out, as it is of such construction that the floating ring and O-ring are arranged between the packing box and equipment main unit.

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