1.
On units to be doweled (except those noted above), drill through two diagonally opposite feet of the
pump into the bedplate.
Use a reamer with a ¼" per foot taper. The dowels should extend well into the bedplate but project
above the pump feet.
2.
Drivers should also be doweled but the driver manufacturer should be contacted for instructions.
5.20 Stuffing Box Operation
WARNING:
Packed stuffing boxes are not allowed in an ATEX-classified environment.
1.
Stuffing boxes with packing rings - less quenching liquid or grease lubricator:
1.
Periodically inspect stuffing box to see that there is sufficient leakage to lubricate the
packing and maintain a cool box. Never draw up packing so that the stuffing box heats,
as this will cause damage to both packing and sleeve. Draw up gland nuts slowly and
evenly and only when pump is running.
2.
After pump has been in operation for some time and the packing has been completely run
in, at least 40 to 60 drops per minute of the liquid should be allowed to trickle from the
stuffing box at all times for cooling and lubricating the packing and shaft sleeve.
2.
Stuffing boxes with packing rings-with quenching liquid:
1.
The same precautions as described above apply. However, the amount of leakage
through the packing cannot be easily determined, due to the quenching liquid. In most
cases, the valve on the quenching liquid supply line can be shut off for a short period and
the amount of leakage determined as in step 1 above.
2.
In no instance should the gland be drawn up tight. Never throttle the clean liquid supply
into the stuffing box as a substitute for proper adjustment of packing - a steady flow from
the seal cage into the pump is required to prevent entrance of pumpage into the packing.
3.
Stuffing boxes with packing rings - with grease lubricator:
1.
Operation is the same as directed in step 1 above, with the addition that the handle on
the lubricator should be given a turn or two about every 100 hours of operation.
4.
Stuffing boxes with mechanical seal:
1.
This type of box requires no attention other than to make sure that the circulating lines do
not become clogged.
5.21 Operating at Reduced Capacities
Do not operate a centrifugal pump at greatly reduced capacities or with discharge gate valve closed, be-
cause the energy required to drive the pump is converted into heat. The temperature of the liquid in the
pump may increase until the boiling point is reached. If this occurs, the rotating parts are exposed to va-
por with no lubrication and they may score or even seize to the stationary parts.
NOTICE:
If running clearances have enlarged due to wear, seizure may not take place and continued
operation under these conditions may create an explosive hazard due to the confined vapor
under high pressure and temperature.
To guard against possible damage, protective devices are available, such as:
5.20 Stuffing Box Operation
46
3175 Installation, Operation and Maintenance Instructions
