6 stopping and shutdown – Flowserve MEN User Manual

Page 24

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MEN USER INSTRUCTIONS ENGLISH 71576288 - 02/13

Page 24 of 36

flowserve.com

SAFETY INSTRUCTIONS WHEN THE PUMP IS
RUNNING:

If hot or freezing components of the machine

can present a danger to operators, they must be
shielded to avoid accidental contact. If a 100 %
protection is not possible, the machine access must
be confined to the maintenance staff only.

If the temperature is greater than 80 °C (176

°F), a warning plate must be clearly placed on the
pump.

It is strictly forbidden to open switch

cupboards, switch boxes, or all other live electric
equipment. If it is necessary to open them in order to
take readings, to carry out tests or adjustments for
example, only a skilled technician may do them with
adapted tools. Make sure that physical protection
against electrical risks is used.

5.5.4 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

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 reduce with time.

5.5.5 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 site on the bearing
housings of the pump in the fully commissioned as
new condition.

The example (N) value is given for the preferred
operating flow region (typically this may extend to 70
to 120 % of the pump best efficiency point); outside
the preferred flow region the actual vibration
experienced may be multiplied by up to 2.

These standard values can vary with the rotational
speed and the power absorbed by the pump. For
any special case, do not hesitate to consult us.
Measuring vibration at regular intervals will then
show any deterioration in pump or system operating
conditions.

Vibration Velocity -

unfiltered

Horizontal Configuration

mm/s (in./s) r.m.s.

Normal N

5.6 (0.22)

Alarm N x 1.25

7.1 (0.28)

Shutdown Trip N x 2.0

11.2 (0.44)


5.5.6 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

90 (120) to 150 (200)

6

Above 150 (200)

Refer

Where duty and standby pumps are installed it is
recommended that they are run alternately every
week.

5.6 Stopping and shutdown

According to hydraulic conditions of

the installation and its automation degree, stop and
restart procedures can have different forms.
Nevertheless all of them must respect imperatively
the following rules:

5.6.1 Stopping < 1 hour
a) Isolate motor.
b) Avoid reverse rotation of the pump.
c) Make sure that the discharge line pressure does

not reach the foot valve.


5.6.2 Stopping < 1 month
a) Isolate motor.
b) Avoid reverse rotation of the pump.
c) Make sure that the discharge line pressure does

not reach the foot valve.

d) Close the outlet valve. Eventually close the inlet

valve.

e) Switch off external power supply,

flushing/quench, cooling liquid.

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