Flowserve Chemstar standard - Manual (Page 19)

CHEMSTAR USER INSTRUCTIONS ENGLISH 71569185 02-10
Page 19 of 44 flowserve.com
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.
5.8.3 Pumps fitted with repeller and gland
packing
Before starting the pump, flood the suction, ensure
that the shaft can rotate freely and that the gland
leaks to an acceptable level of 30 to 120 drops per
minute.
If not, adjust the gland follower nut [6580.3] to make
sure that the gland packing [4130.1] is wetted either
by pumped liquid or by externally flushed clean liquid.
Leakage will stop completely as soon as the pump is
started and the hydrodynamic sealing takes place.
5.8.4 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.
•
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) ºC (t+tb-ta+10) ºF
and the trip at 100 ºC (212 ºF) for oil lubrication
and 105 ºC (220 ºF) 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 5.2.5
for further information.
5.8.5 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 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
Horizontal pumps
≤≤≤≤ 15 kW mm/sec
(in./sec) r.m.s.
> 15 kW
mm/sec (in./sec)
r.m.s.
Normal N ≤ 3.0 (0.12) ≤ 4.5 (0.18)
Alarm N x 1.25 ≤ 3.8 (0.15) ≤ 5.6 (0.22)
Shutdown trip N x 2.0 ≤
6.0 (0.24)
≤
9.0 (0.35)
Where a grease lubricated unit is utilised in a vertical
shaft configuration with a duck-foot bend onto the
pump suction, the following apply:
Vibration velocity
– unfiltered
Vertical configurations
mm/sec (in./sec) r.m.s.
Normal N ≤
7.1 (0.28)
Alarm N x 1.25 ≤
9.0 (0.35)
Shutdown trip N x 2.0 ≤ 14.2 (0.56)
5.8.6 Stop/start frequency
Pump sets are normally suitable for the number of
equally spaced stop/starts per hour shown in the
table below. Check capability of the driver and
control/starting system before commissioning.
Motor rating kW (hp)
Maximum stop/starts
per hour
Up to 15 (20) 15
Between 15 (20) and 90 (120) 10
Above 90 (120) 6
Where duty and standby pumps are installed it is
recommended that they are run alternately every
week.
5.9 Stopping and shutdown (all series)
a) Close the outlet valve, but ensure
that the pump runs in this condition for no more
than a few seconds.
b) Stop the pump.
c) Switch off flushing and/or cooling/heating liquid
supplies at a time appropriate to the process.
d) For prolonged shut-downs and
especially when ambient temperatures are likely
to drop below freezing point, the pump and any
cooling and flushing arrangements must be
drained or otherwise protected.