WIK USER INSTRUCTIONS ENGLISH BO2662 5/09
Page 36 of 76
should both lube oil pumps lose pressure (see lube
oil console manufacturer's data in Section 10).
11) Verify:
a) That flow rate of pump is as required
b) That lube oil system, cooling system, and
seal flush system do not evidence leakage
12) Observe differential pressure indicator of
differential pressure and switch unit or
differential pressure indicator, whichever is
applicable (see lube oil console manufacturer's
data in Section 10). If the differential pressure of
lube oil exceeds is that specified by lube oil
console manufacturer, manually route lube oil
through clean filter in accordance with its
manufacturer's instructions in section 10.
Otherwise lube oil passage through filter is
nominal.
13) Observe lube oil reservoir level glass; level of
lube oil should appear between minimum and
maximum marks on glass; if there are no marks;
lube oil level should appear higher than 1/2
length of glass but not higher than 2/3 its length.
To replenish reservoir, see section 5.1.2.5.
14) Observe running of pump. If running becomes
rough (i.e., vibration increases) or noisy or pump
suction and discharge gauges give erratic
readings, shut down pump and determine cause
(see section 7).
15) Observe running of driver or driving units, (i.e.,
speed increaser gear, motor, turbine, diesel) and
couplings and verify that it is nominal (see their
manufacturer's instructions in section 10).
16) If your unit is equipped with a metered orifice in
the balancing leak-off line, then observe the
differential pressure in that line periodically. This
differential pressure is an accurate indication of
the leakage across the pressure reducing
bushing, which will give an overall indication of
the level of wear of the wearing rings and
bushings inside of the pump. When this
differential pressure has increased by a factor of
4 over its initial value at pump installation or
overhaul, then consideration should be given to
pump overhaul and renewal and/or replacement
of the pump wear components.
5.8.2 Operating at reduced capacity
The centrifugal pump may be operated below rated
capacity providing that flow remains above minimum.
But you should remember that throttling the
discharge reduces both capacity and efficiency of
the pump. Because of the drop in efficiency, a
greater portion of the horsepower input goes into
heating the liquid in the pump. Unless the flow
through the pump is sufficient to carry away this
excess heat, the liquid will boil and the pump will
become vapor bound and seize immediately.
Reducing capacity by throttling the
suction valve is ineffective and hazardous and
should not be attempted because it may reduce the
pressure in the eye of the impeller below the
required minimum, causing destructive cavitation or
seizure.
Operation may be initiated by:
1) Throttling the discharge
2) Reducing the speed
3) Throttling the discharge and reducing the speed.
To take pump off line and put it in hot
standby, see section 5.9.
5.9
Stopping and shutdown
There are usually two circumstances for stopping the
pump: cold shutdown and hot standby. Normally,
only those pumps that require warm-up are placed in
hot standby. The recommended procedures for
affecting these shutdowns are given below.
5.9.1 From on-line operation to cold shutdown
To prevent interior parts from becoming dry and
seizing, the pump should be shut down rapidly as
follows:
1) See that valves in minimum flow circuit (see
your plant's data file) are open, then close
discharge valve (or place discharge valve in
bypass).
The discharge valve should be
closed by the time the pump stops rotating to
prevent backward rotation of the pump should the
check valve stick.
2) Cut power to driver; recommended procedure
for turbine unit is to stop turbine by tripping
emergency over speed trip.
To shut down the lube system and cooling
water system of the lube oil console, see the lube oil
console manufacturer's instructions and drawings in
the section 10.
3) When the pump has stopped rotating, shut down
lube oil system.
4) Close off valves in all vent lines and cooling
liquid lines (as furnished) to applicable units:
