Rainman Electric Manual
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Page 3
Getting to know your system
Desalination basics
Desalination sounds complex, but it’s
quite simple in principle.
The Rainman watermaker operates through a process called reverse osmosis
(RO). In its most simple terms, the system draws seawater up, filters out
sediment and particulates, then puts the clean seawater under high pressure
to pass through an RO membrane. The RO membrane is a semi-permeable
polyamide thin-film composite.
A traditional filter, like our prefilter, works by passing all the water through it.
The fine construct prevents larger particles from getting through and they are
captured on the filter material. When a lot of particles have been captured on
the filter
and it’s dirty
, you change it.
In contrast to a traditional filter, the RO process has filtered seawater passed
across the membrane surface at high pressure. Keeping the description simple,
the system is essentially extracting a small percentage of the freshwater from
the seawater stream. The majority of the water and all of the salt continues in
the flow and out the brine waste water hose. The salt does not accumulate on
the membrane, which is why RO membranes do not need to be cleaned or
replaced regularly.
Since bacterias and viruses are much larger than salt molecules, they stay in
the main seawater stream and are passed out with the brine waste water.
