Bmsx System; Flushing - Grundfos BMS hs Assembly, Installation And Operating Instructions

9.4 BMSX system

This procedure describes how to shut down the BMSX system.
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Fig. 8 Example of BMSX system
Procedure
1. Ramp down and stop the BMS hs pump (6). See section
9.1 BMS hs pump.
2. Ramp down and stop the BMS hp pump (14).
3. Stop the seawater feed pump (1).
4. Depressurise the system by opening the valve (20).
5. Start the fresh-water flush pump (26), and flush the system
with fresh water (15) (minimum 2 bar for flushing).
6. Start the BMS hp pump (14), ramp it up to 1700rpm and let it
run until the salinity is lower than 1000 ppm TDS. To ensure
efficient flushing of the system, open the valve (20).
7. Start the BMS hs pump (6) and ramp it up to minimum 1700
rpm or until the salinity is lower than 1000 ppm TDS.
To flush the thrust bearing and shaft seal of the BMS
hs pump, start the pump to allow the fresh water to
enter into the thrust bearing.
If the flushing takes more than 10 minutes, reduce
the flow to maximum 10 % of the rated flow rate.
During periods of inactivity, fill the pump with clean
fresh water.
8. Stop the BMS hs pump (6), the BMS hp pump (14) and the
fresh-water flush pump (26).
9. Close all valves to keep the fresh water in the system during
shutdown.
10. If the system is taken out of operation for a long period, take
precautions to inhibit biological growth. The system units must
be given a final flush with the same solution used to preserve
the membranes.
1000 ppm TDS
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9.5 Flushing

BMS pumps can be flushed in the flow direction.
Flushing of the booster pumps is very important, especially when
the pumps are used for pumping seawater or water with
chemicals.
If seawater is left in the pumps while they are stopped, there is a
risk of crevice corrosion of the stainless steel.
If water containing chemicals is left in the pumps while they are
stopped, the rubber parts of the pump or motor may be affected.
In case the cleaning solution contains chemicals which may affect
the rubber in the pump and pressure exchanger of BMSX, install
a bypass. A pressure exchanger must be isolated during
chemical cleaning.
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