Table 1. Major Functional Components of the ROWPU System (Refer to Figure 6) (Cont)

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Figure 2. Emergency Switchboard

TM-55-1925-273-10-1 Inland and Coastal Large TUG (LT) NSN 1925-01-509-7013 (EIC XAG) Manual

AFFF SYSTEM SHUTDOWN

TM 55-1925-273-10-1

0028 00

Table 1. Major Functional Components of the ROWPU System (continued) (Refer to Figure 6)

Item No.

Nomenclature

Description

(Refer to

Figure 6)

Reverse Osmosis Membranes

The membranes convert filtered raw water into drinking water by

allowing only water molecules to pass through its spiraled membrane.

The high pressure/low volume pumps push raw water through the

membranes to make fresh water, and they push the brine out of the

membranes and overboard.

Solenoid Operated 3-Way

The solenoid operated 3-way diverter valves are controlled by the

Diverter Valve

system controllers (figure 6, item 14). The controllers sense the

salinity of the product water output by the membranes. If the product

water salinity is within tolerances, the product water is sent to the

brominator and on to the potable water tanks. If product water salinity

is too high, the product water is diverted and sent overboard as

ROWPU system product brine.

ROWPU System Product

Brine is the by-product of reverse osmosis. The brine is pumped

Brine Discharge

overboard via the general service system overboard discharge. The

ROWPU system is protectedfrom the general service system by

means of a check valve that acts as a backflow preventor.

Fresh Water Flush Pump

The fresh water flush pump is a low pressure pump that is used to

clean and to prepare the ROWPU system for use. It is a 24 Vdc

pump controlled by the system controller. The fresh water pump

uses filtered potable water to purge raw water from the filtration

system and from the raw water side of the reverse osmosis membranes.

When the ROWPU is not in use, the system controllers automatically

perform a fresh water flush once a week. The fresh water flush serves

to prolong the life of the membranes, and it eliminates the need to

`pickle' the membranes for layup.

Charcoal Filters

The charcoal filters remove sediment and foul odors from the potable

water used during flushing cycles. Thecharcoal filters also block

bromine and chlorine from passing into the reverse osmosis

membranes. The charcoal filters are secured when the ROWPU is

making product water, and are protected by cutoff valves and a

backflow preventor.

System Controllers

The system controllers are microprocessor-based water purification

monitors and controllers. They control power to the pumps, monitor

the quality of the output potable water, and monitor system operating

pressures. The system controller turns the high pressure and fresh

water flush pumps ON and OFF as required by system demands and

operating conditions. The system controller also measures the salinity

of the product water and controls the position of the solenoid operated

3-way diverter valve accordingly. Finally, the system controllers

monitor system operating pressures. Any system pressure out of

tolerance will cause the controller to stop the process and indicate an

alarm. Power input to the system controllers is 450 Vac and 24 Vdc.

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