Service manual

20
E.11 SHAFT PACKING (STUFFING BOX) LEAKAGE
Pumps with packing-type seals must be checked to insure packing gland is not too tight.
Excessive gland pressure on packing will cause a scored shaft, overheating and rapid
breakdown of packing. Keep gland nuts only finger tight. After new packing has been installed,
gland nuts should be tightened evenly but only tight enough to seat packing rings properly.
Then, loosen gland nuts and re-tighten finger tight. The final adjustment should allow a leakage
of approximately ten drops per minute while pump is operating. This leakage is necessary to
lubricate the packing. Provide a place for safe draining and disposal of this leakage.
WARNING
If not appropriately collected, packing leakage may make floor slippery and/or
expose personnel to hazardous fluids.
E.12 THERMAL SHOCK AND OPERATING TEMPERATURE LIMITS
During pump start-up, as well as during pump operation, pump must not have fluid entering it
that is 50°F (28°C) hotter than the temperature of the pump. This constitutes a thermal shock
condition that can lead to pump failure. Rapid temperature changes beyond this limit must be
avoided. Unless approved by Imo, liquids entering pump inlet must not be hotter than 225° F
(107° C) nor colder than 0° F (-18° C). Most pumps also have temperature limits of 225° F to
0° F. Maximum rate of temperature change during pump heating or cooling should be about
1.5° F/minute (0.8° C/minute). A heated or cooled pump should be held at its start-up
temperature for at least an hour prior to start-up. This will insure uniform temperature
distribution throughout pump assembly.
CAUTION ATTENTION
Never exceed minimum or maximum allowable pump or liquid temperature. Do
not expose equipment to thermal shock. Differences in metallurgy and their
respective coefficients of expansion could cause distortion of pump parts resulting
in a breakdown condition. Use of insulation and heating jacket or heat tracing to
maintain pump at liquid temperature is recommended in high temperature
applications.
E.13 SHUTDOWN
If system is to be shut down for a short period, do not drain pump as this would require re-
priming at start-up. If pump is to be stored, apply a rust-inhibiting agent (one compatible with
all pump materials) to all internal and external surfaces, especially those that are machined.
F. MAINTENANCE
DANGER
BEFORE starting any maintenance procedure, do the following:
• Shut off all power switches and circuit breakers.
• Remove any electrical service fuses.
• Lock electrical service panel supplying power to driver.
• Shut, wire or chain, and lock all valves in pump inlet/outlet piping.
• If applicable, shut off any steam or other fluid supply lines to pump.