Flowserve MNV - Manual (Page 26)

MNV & MNZ USER INSTRUCTIONS ENGLISH 71569188 11/04
Page 26 of 47
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5.7.2 Pump start up
The procedure for starting the unit will vary
somewhat with each installation, however the
following steps generally apply:
Turn off power to the driver.
a) Turn the pump over by hand to verify that the
pump rotor turns freely. If it is bound, do not
operate the pump until the cause of the trouble is
located.
b) Make sure the suction valve is open
c) Ensure flushing and/or cooling/
heating liquid supplies are turned ON before
starting the pump
d) CLOSE the outlet valve
e) Prime the pump.
f) Ensure all vent connections are closed
before starting.
g) Start the driver per the manufacturer's instruction.
h) Open the discharge valve slowly as pressure is
built up on the discharge side of the pump. If the
valve does not open within three minutes,
shutdown the unit and determine the cause.
i) If NO pressure, or LOW pressure,
STOP the pump. Refer to section 7, Faults;
causes and remedies , for fault diagnosis.
j) Adjust the gland nuts on the packing.
k) When in service, bearing temperature, suction,
discharge, and stuffing box pressure, stuffing box
operation, noise, and vibration for several hours.
5.7.3 Normal vibration levels, alarm and trip
For guidance and general data ,the subject pump
types with rigid supports are classified based on
power ratings as provided by Hydraulic Institute
standards.
Alarm and trip values for installed
pumps should be based on the actual measurements
(N) taken on the pump in a fully commissioned (new)
condition. Measuring vibration at regular intervals
and recording will help to track any deterioration in
pump or operating conditions.
Motor rating kW
(hp)
Vibration
velocity-
unfiltered
mm/sec (in./sec)
rms
0.75-to 7.5 (1-10) N 6.6 (0.22)
7.5 to 75 (10-100) N 6.6 (0.22)-8.0(0.32)
100-298 (100-400) N 8.0 (0.32)-8.6(0.34)
298-750 (400-1000) N 8.6 (0.34)-
Alarm =N X1.25; Trip= N X2.0
5.7.4 Motor start/stop frequency
Even though motors are normally suitable for at least
two consecutive starts, it is recommended to restart
only after coasting to rest between starts (minimum
of 15 minutes gap is recommended) with the motor
initially at ambient temperature. If more frequent
starting is necessary, refer to driver manufacturer’s
User Instructions.
The number of motor start and stops
in any given time affects motor life.
If the motor is expected to experience multi
starts in any given time, please refer to the driver’s
user instructions before the pump is put into
operation.
5.8 Running or operation
5.8.1 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.
5.8.2 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 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 a steady
leakage and the gland nuts tightened by 10 degrees
at a time until leakage is reduced to an acceptable
level. As a thumb rule a minimum of 30 drops
/second for every inch of sleeve diameter will keep
the gland in safe operating condition. Seating of the
packing may take another 30 minutes.