TM 10-4610-239-24
TM 08580B-24/3
1-12. SAFETY, CARE, AND HANDLING. Observe all WARNINGS, CAUTIONS, and NOTES in this manual. This
equipment can be extremely dangerous if these instructions are not followed.
Section III. PRINCIPLES OF OPERATION
1-13. OVERALL SYSTEM OPERATION. This section contains a description of how the ROWPU works. This
paragraph describes the operation of the complete system. Paragraph 1-14 describes the functions of each of the main
components. (See figure FO-1.)
a.
Raw water is drawn through a strainer, which keeps large quantities of trash from entering the system. Depending
on the distance between the ROWPU and water source, one or two raw water pumps are used to move the raw
water. As water enters the ROWPU, the chemical feed metering pump assembly adds two chemicals to it. The
polymer drive unit adds polyelectrolyte (polymer) solution and the sodium hex drive unit adds sodium
hexametaphosphate (sodium hex). The polymer material collects small pieces of floating solid matter into groups
large enough to be removed by the multimedia filter. Sodium hex prevents scaling.
b.
The raw water containing the added chemicals flows through the multimedia filter, which performs first stage
filtration by breaking down impurities, then through cartridge filter, second stage of filtration, which further
removes impurities. The R.O. pump then raises the pressure to that needed to force water through the
membranes of the R.O. elements. Since the R.O. pump output pulsates, it is passed through the pulse
dampener, which smoothes the
flow before the water reaches the R.O. elements. These R.O. elements are
connected in series and the waste water
(brine) from all elements is sent out of the ROWPU to the
backwash water tank. When that tank is full, any additional brine is discharged to the ground downstream of the
suction hose strainer.
c.
The chlorine drive unit adds chlorine to the filtered output of the R.O. elements to kill any bacteria present and
the chlorinated water is carried out of the ROWPU through a hose for storage in two product water tanks
connected in series. When water is needed, the distribution pump sends the stored potable (drinkable) water
through the distribution nozzle to a container provided by the user.
d.
There are two cleaning procedures performed after 20 operating hours and one cleaning procedure performed
whenever water flow rate or water pressure exceed certain limits. After 20 operating hours, citric acid is injected
into the system before ROWPU shutdown. After shutdown, the multimedia filter is backwashed. When system
conditions require it, an R.O. element cleaning procedure is performed.
e.
In the first procedure, the citric acid drive unit injects citric acid into the multimedia filter output. The citric acid
removes scaling that accumulated in the system during operation. When procedure is complete, ROWPU is shut
down.
f.
After shutdown, multimedia filter backwash is manually activated then controlled by a solid-state timer. Brine
stored in the backwash tank is forced backward through the multimedia filter by the backwash pump.
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