Flowserve Gearex Rotary Gear Pumps External and Internal Bearing - Manual (Page 32)

EXTERNAL GEAREX USER INSTRUCTIONS ENGLISH 71569246 (2167B-E1)
Flowserve Pump Division 32
®
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.
5.9.4 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)
°
C [(t+tb-ta+10)
°
F]
and the trip at 100
°
C (212
°
F) for oil lubrication.
5.9.5 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
mm/s (in./s) r.m.s.
GEAREX
VERTICAL
GEAREX
Normal N ≤
5.6 (0.22)
≤
7.1 (0.28)
Alarm N x 1.25 ≤
7.1 (0.28)
≤
9.0 (0.35)
Shutdown trip N x 2.0 ≤ 11.2 (0.44) ≤ 14.2 (0.56)
5.9.6 Stop/start frequency
Pump sets are normally suitable for the number of
equally spaced stop/starts per hour shown in the
table below. Check actual 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.
5.10 Stopping and shutdown
5.10.1 Short term
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) Leave open the valve supplying auxiliary sealing
fluid to maintain prime while the pump is idle.
d) On pumps with steam jacketed bodies and/or
stuffing boxes, maintain steam flow to prevent
pumping liquid from setting up in the internals of
the pump.
5.10.2 Long term
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) On pump with steam jackets, shut off steam flow
and allow pump to cool.
e) 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. Refer to section
2.4.2
Long-term storage.
5.11 Hydraulic, mechanical and electrical
duty
This product has been supplied to meet the
performance specifications of your purchase order,
however it is understood that during the life of the
product these may change. The following notes may