MDX [en-US]
34
9
Shaft Seal
9.1
Mechanical Seal
CAUTION
Example Mechanical Seal cross section
Mechanical seals require safety checks prior to start-up such as
removing seal assembly fixtures, checking axial alignment,
checking torques etc. Refer to the mechanical seal operating
manual for all required safety checks.
Mechanical seals are precision devices which require special care for their proper
operation. The instruction manual for the seal should be consulted for special
storage, start-up, and maintenance requirements.
For information on mechanical seals, consult the manufacturer’s manual.
9.1.1
Mechanical Seal Assembly and Disassembly
Review the mechanical seal arrangement and determine the layout of the mechanical seal assembly. Some mechanical seals
have an adapter which must be placed on the shaft before the hub plate and/or casing is installed while others can be installed
after the casing is installed.
Always refer to the mechanical seal maintenance manual for further instructions.
9.2
Stuffing Box
GIW offers three stuffing box designs. In general, more flush water will result in less wear on the packing and sleeve, so the
decision of which design to use depends on the severity of the service, quality of the seal water and relative importance of seal
life vs. water supply costs.
The Throat Bushing design is the standard product offering in GIW’s LSA-style standard pumps. It combines the lantern
ring with a longer, tight tolerance collar and provides a compromise between the Forward Flush and KE designs in
difficult applications where water reduction is needed. It produces a throttling effect that restricts seal water flow in the
pump while maintaining pressure and flow at the packing rings. This reduces the amount of water that enters the
process flow while providing an easy-to-maintain stuffing box assembly. The Throat Bushing design is also available in
a variation incorporating the SpiralTrac™ technology. This allows for flowrates to be reduced by more than 50% when
compared to the less efficient Forward Flush boxes, while still maintaining acceptable packing life and shaft sleeve
wear.
The KE design is used where minimum water usage is desired. One or two rings of packing are located between the
lantern ring and the wear plate to restrict seal water flow into the pump cavity, while the packing rings behind the lantern
ring seal to atmosphere. It is the most sensitive design to variable operating conditions and abrasive wear, and requires
more careful maintenance.
The Forward Flush design design has historically been used where gland water supply is plentiful, and the addition of
water to the process flow is not problematic; however, please note that GIW is phasing out the Forward Flush design
stuffing box due to global water conservation initiatives. This stuffing box is no longer available on GIW’s standard
pumps.
Throat Bushing
KE Design
Forward Flush
1
Packing
2
Throat Bushing
3
Lantern Ring
1
2
1
1
3
3
1
Summary of Contents for GIW MDX
Page 53: ...MDX en US 53 14 Notes...
