PHL USER INSTRUCTIONS ENGLISH 00079593
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10/10
Page 18 of 31
g)
Do not run the pump with the outlet
valve closed for a period longer than 30 seconds.
h) If NO pressure, or LOW pressure, STOP the
pump. Refer to section 7,
Faults; causes and
remedies
, for fault diagnosis.
5.9 Running the pump
5.9.1 Pumps fitted with packed gland
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 ring to
avoid excess temperature. If no leakage takes place
the packing will start overheating. If overheating takes
place the pump should be stopped and allowed to cool
down 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, not even
for a short time.
5.9.2 Pumps fitted with mechanical seal
Mechanical seals are not adjustable. 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 faces.
External flush or quench should be
started before the pump is run and allowed to flow for
a period after the pump has been stopped.
Never run a mechanical seal dry, not
even for a short time.
5.9.3 Bearings
If the pumps are working in a potentially
explosive atmosphere, temperature or vibration
monitoring 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 been 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 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 reduced with time. (Refer to
section 6.1.1 for further information.)
5.9.4 Normal vibration levels, alarm and trip
For guidance, pumps generally fall under a
classification for rigid support machines within the
International rotating machinery standards (API
610, latest ed./ISO 13709, latest ed.) 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 the pump in the fully
commissioned as new condition. Measuring
vibration at regular intervals will then show any
deterioration in pump or system operating
conditions.
Vibration velocity
–
unfiltered
mm/s (in./s) r.m.s.
Overhung pumps
Normal
N
3.0 (0.12)
Alarm
N
x 1.25
3.9 (0.15)
Shutdown trip
N
x 2.0
6.0 (0.18)
5.9.5 Stop/start frequency
Pump sets are normally suitable for the number of
equally spaced stop/starts per hour shown in the
table below. Check actual capability of the driver
and control/starting system before commissioning.
Motor rating kW (hp)
Maximum stop/starts
per hour
Up to 15 (20)
6
Between 15 (20) and 90 (120)
6
Above 90 (120)
4
Where duty and standby pumps are installed it is
recommended that they are run alternately every
week.
