9 stopping and shutdown, 10 hydraulic mechanical and electrical duty – Flowserve APKD User Manual
Page 34
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APKD DOUBLE-CASE, DOUBLE-SUCTION USER INSTRUCTIONS 26999903 07-13
Page 34 of 55
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5.8.2
Pumps fitted with packed glands
If the pump has a packed gland, there must be
some leakage from the gland. Gland nuts should
initially be finger-tight only. Leakage should take
place soon after the stuffing box is pressurized.
The gland must be adjusted evenly to give
visible leakage and concentric alignment of the
gland ring to avoid excess temperature. If no
leakage takes place, the packing will begin to
overheat.
If overheating takes place, the pump should be
stopped and allowed to cool before being re-
started. When the pump is re-started, check to
ensure leakage is taking place at the packing
gland.
If hot liquids are being pumped it may be necessary
to loosen the gland nuts to achieve leakage.
The pump should be run for 30 minutes with steady
leakage and the gland nuts tightened by 10
degrees at a time until leakage is reduced to an
acceptable level, normally a minimum of 40-60
drops per minute is required.
Care must be taken when adjusting the gland
on an operating pump. Safety gloves are essential.
Loose clothing must not be worn to avoid being
caught by the pump shaft. Shaft guards must be
replaced after the gland adjustment is complete.
Never run gland packing dry, even
for a short time.
5.8.3
Pumps fitted with mechanical seal
Mechanical seals require no adjustment. Any slight
initial leakage will stop when the seal is run in.
Before pumping dirty liquids, it is advisable, if
possible, to run in the pump mechanical seal using
clean liquid to safeguard the seal face.
External flush or quench should be
started before the pump is run and allowed to flow
for a period after the pump has stopped.
Never run a mechanical seal dry,
even for a short time.
5.8.4
Pump and motor bearing temperature
If the pumps are working in a potentially
explosive atmosphere, temperature or vibration
monitoring at the bearings is recommended.
If pump bearing temperatures (such as thrust
bearings) are to be monitored it is essential that a
benchmark temperature is recorded at the
commissioning stage and after the bearing
temperature has stabilized.
Record the bearing temperature (t) and the
ambient temperature (ta)
Estimate the likely maximum ambient
temperature (tb)
Set the alarm at (t+tb-ta+5) C [(t+tb-ta+10) F]
and the trip at 100
C (212 F) for oil lubrication
and 105
C (220 F) for grease lubrication
It is important, particularly with grease lubrication,
to keep a close watch on the bearing temperatures.
After startup the temperature rise should be
gradual, reaching a maximum after approximately
1.5 to 2 hours. This temperature rise should then
remain constant or marginally reduce with time.
5.9 Stopping and shutdown
a) Close the outlet valve, but ensure that the
pump runs in this condition for no more than a
few seconds.
b) Stop the pump.
c) Switch off flushing and/or cooling/heating liquid
supplies at a time appropriate to the process.
For prolonged shutdowns and
especially when ambient temperatures are likely to
drop below freezing point, the pump and any
cooling and flushing arrangements must be drained
or otherwise protected.
5.10 Hydraulic mec
hanical and electrical
duty
This product has been supplied to meet the
performance specifications of your purchase order,
however it is understood that during the life of the
product these may change. The following notes may
help the user decide how to evaluate the implications
of any change. If in doubt contact your nearest
Flowserve office.