Flowserve L Worthington Simpson - Manual (Page 20)

L and U USER INSTRUCTIONS ENGLISH 85392721 07-12
Page 20 of 36 flowserve.com
5.7 Running the pump
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 packed gland
+ P
- P
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 pressurised.
The gland must be adjusted evenly to give
visible leakage and concentric alignment of the gland
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 then 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 pump 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.
•
Record the bearing temperature (t) adjacent to
the bearing 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 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 should then remain constant or
marginally reduce with time. (Refer to section 6.2.3.2
for further information.)
5.7.5
Normal vibration levels, alarm and trip
For guidance, pumps generally fall under a classification
for rigid support machines within the International
rotating machinery standards and the recommended
maximum levels below are based on those standards.
Alarm and trip values for installed
pumps should be based on the actual measurements
(N) taken on site on the bearing housings of the
pump in the fully commissioned as new condition.
The example (N) value is given for the preferred
operating flow region (typically this may extend to 70
to 120% of the pump best efficiency point); outside