10
11.7 BM hp circulation pump
This section and the subsequent subsections make references to
the piping and instrumentation diagram, fig. 12.
To start up the BM hp circulation pump, proceed as follows:
1. Open the solenoid valve (V4) on the BM hp circulation pump
(P4).
2. Ensure an inlet pressure on the pump (min. 1 bar and
max. 80 bar).
3. Wait 3 to 5 minutes to ensure optimum venting.
4. Close the solenoid valve on the BM hp circulation pump.
5. Start the BM hp circulation pump.
In systems involving the risk of water hammer in connection with
start/stop, the necessary measures must be taken to reduce this
risk, e.g. by installing a diaphragm tank.
During operation, the inlet pressure must be checked in
accordance with section
.
The BM hp circulation pump is now ready for operation.
11.7.1 Checking the direction of rotation
Procedure:
1. Close the control valve (V2) on the discharge side of the
BM hp circulation pump (P4) to approx. 1/3 of maximum flow.
2. Start the BM hp circulation pump, and record discharge
pressure and flow readings.
3. Stop the pump, and interchange two of the phases to the
motor.
4. Restart the pump, and re-record discharge pressure and flow
readings.
5. Stop the pump.
6. Compare the results recorded under points 2 and 4. The
connection which gave the larger pressure and flow is the
correct direction of rotation.
The check of the direction of rotation should last for the shortest
possible time.
12. Checking the operation of the BMPX system
Check the following at suitable intervals:
•
Flow and pressure.
•
Current consumption.
•
Pressure drop over the prefilter.
Replace the filter element when "clogged filter" is indicated.
•
Whether the motor ball bearings are worn.
•
Whether the shaft seal is leaky.
The shaft seal is lubricated by the pumped liquid. Small
quantities of liquid are therefore drained via the drain hole in
the coupling housing.
•
Whether the sound pressure level has changed.
It is recommended to write the operating data in the log books
supplied with the system. The data can be useful for maintenance
purpose. The log books are shown on pages 91 to 93.
13. Maintenance
See installation and operating instructions for BMP pumps.
14. Motor bearings
Under optimum operating conditions, the operating life of the
motor ball bearings is approx. 20,000 operating hours. After that
period, the bearings must be replaced. The new bearings must be
filled with grease.
15. Shut-down procedure
See section
for precautions to be taken
when shutting down the system.
1. If operated by variable-frequency drive, speed down the BMP
hp feed pump (P3) until the system pressure drops below
28 bar.
If not operated by variable-frequency drive, open the solenoid
valve (V4) until the pressure is below 28 bar and go to step 2.
2. Stop the BMP hp feed pump (P3), followed by the BM hp
circulation pump (P4), and stop the sea-water feed pump (P1).
Caution:
To prevent overflow, make sure that the flow through
the X-Changer is reduced by throttling the low-pressure reject-
water valve (V3).
16. Periods of inactivity
In the case of periods of inactivity, various precautions must be
taken to protect the system and ensure long life.
The precautions to be taken if the system is to be inactive for a
certain period appear in the table:
* Use the same solution that is used to preserve the membranes.
For further information on anti-freeze liquids, please contact
Grundfos.
16.1 Start-up after a period of inactivity
The precautions to be taken if the system has been inactive for
a certain period appear in the table:
Note
The BM hp circulation pump must be filled with
water before start-up.
Warning
The BM hp circulation pump is not allowed to run
against a closed discharge valve for more than
5 seconds as this will cause an increase in
temperature/formation of steam in the pump
which may cause damage to the pump and motor.
If there is any risk of the BM hp circulation pump
running against a closed discharge valve or no
flow, a minimum liquid flow through the pump
should be ensured by connecting a bypass/a
drain to the discharge side of the pump. The
drain can for instance be connected to a tank.
The solenoid valve must be opened three times
a day (every 8 hours) for 30 seconds at a time.
Action
30 min.
1 month
3 months
6 months
Flushing
x
x
x
x
Fill the pumps with fresh water
x
x
x
x
Preserve the pump*
x
x
x
Note
The normal stop procedure must be followed
step by step.
Caution
Never just drain the pump!
Action
30 mi
n.
1 month
3 months
6 months
Vent air from the system
x
x
x
x
Check the flows FM2 and FM3
x
x
x
Note
The normal start-up procedure must be followed
step by step.
