Condition
Action
An outside source of clean compatible liquid is
required.
You must connect the piping to the lantern ring connection with a 40
to 60 drops-per-minute leak rate. The pressure must be 1.01 kg/cm
2
| 15 psi above the stuffing box pressure.
5.7.5 Dynamic-seal option
WARNING:
Dynamic seals are not allowed in an ATEX-classified environment.
The dynamic seal consists of two parts:
•
Repeller seal
•
Secondary seal (one of the following):
•
Graphite packing
•
Elastomenic face seal
Table 12: Dynamic seal part function
Part
Function
Repeller seal
A repeller seal prevents liquid from entering the stuffing box during operation. The
repeller normally does not require a flush. However, for services that allow a build-
up of solids on the repeller, you must install a flush connection. If a danger of
freezing exists, then you must install a drain connection to drain the repeller cham-
ber.
Secondary seal (graphite pack-
ing)
This secondary seal prevents leaks during pump shutdown and is comprised of
the following:
•
Graphite packing – Graphite packing provides adequate life running dry but
can provide longer performance if lubricated with clean water or grease.
•
If you lubricate with clean water, then the repeller reduces both the
quantity and pressure of seal water that is necessary. If the suction
head is less than the repeller capability, then the stuffing box pressure
is the same as the atmospheric pressure. Water pressure for the seal
must be high enough to overcome static head when the pump is not
operating to keep pumped fluid out of the packing. There must be
enough flow to cool the packing.
•
If you lubricate with grease, then you must use spring-loaded grease
lubricators to maintain a constant supply.
•
Elastomeric face seal – The elastomeric face seal consists of an elastomer
rotary fitted to the shaft and a ceramic stationary seat fitted in the gland. To
set an elastomeric face seal, refer to Set an elastomeric face seal. This seal
is designed to run dry, so no flush is necessary.
5.7.6 Set an elastomeric face seal
This procedure ensures that the elastomeric seal attains proper contact. No other adjustments are nec-
essary.
1.
Remove the gland nuts.
2.
Slide the gland back on the sleeve.
3.
Pull the rotary back on the sleeve until the rotary is about 25 mm | 1 in. beyond the stuffing box
face.
4.
Push the gland back onto the studs, pushing the rotary back along the sleeve.
5.
Tighten the gland nuts.
5.7 Shaft-sealing options
62
Model CV 3196 i-FRAME Installation, Operation, and Maintenance Manual
