Flowserve LPNV Worthington - Manual (Page 28)

LPNV USER INSTRUCTIONS ENGLISH 87900031 – 06/14
Page 28 of 48
alignment check must be made (Refer to
Section 4.3).
5.7.1 Venting the pump
Vent the pump to enable all trapped air to
escape taking due care with hot or hazardous
liquids.
Under normal operating conditions, after the pump
has been fully primed and vented, it should be
unnecessary to re-vent the pump.
5.7.2 Pumps fitted with Gland seal
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 packed gland.
If hot liquids are being pumped it may be necessary
to slacken 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 120 drops per minute is
required. Bedding in of the packing may take
another 30 minutes.
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 up 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.
5.7.3 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.
5.7.4 Bearings
If the pumps are working in a potentially
explosive atmosphere temperature or vibration
monitoring at the bearings is recommended
If bearing temperatures are to be monitored it is
essential that a benchmark temperature is recorded
at the commissioning stage and after the bearing
temperature has stabilized (see 5.2.2 for
temperature limits).
When a oil temperature sensor is provided:
 set the alarm at 82 °C (180 °F) and the trip at 90
°C (194 °F) for high ambient temperature and/or
hot service
When the bearing temperature sensor is provided:
 set the alarm at 93 °C (200 °F) and the trip at
105 °C (220 °F).
It is important, to keep a check on bearing
temperatures. After start up 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.