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Environment
a ver the past two decades, NASA and
its contractors have conducted exten-
sive research on how to assure pure
water for manned spacecraft crews
and how to recycle wastewater for reuse on
future long duration spacecraft. This work
has given rise to a large number of spinoff
products and products for cleansing and
detoxifying water (see also
pages 55 and 110-113) and
in some cases inspired the
formation of new compa-
nies to commercialize the
technology.
Among the latter js
Sensible Technologies, Inc.
(STI), Irmo, South
Carolina, a company
formed in 1989 to exploit a
partic u la r N AS A-d eve 1 o ped
water purification technolo-
gy known as silver ioniza-
tion. In this method, devel-
oped in i he mid-1960s by
Johnson Space Center, a
small lightweight generator
dispensed silver ions in the
potable water supply of the
Apollo spacecraft to kill
ha cteri a i n the wa t e r .
STI originally
focused on using the
technology for cleansing swimming pools,
but its effectiveness in purifying water and
eliminating corrosive chemicals led compa-
ny president Tommy Wood to seek other
applications, such as industrial cooling
towers and industrial process coolers.
Wood recognized that, although
copper/ silver ionization could successfully
eliminate algae and bacteria, something
more was needed to fulfill all the water man-
agement needs
of recirculating
and evaporative
cooling water
systems; the
purification sys-
tem must also
be capable of
eliminating cor-
rosion, debris
and scale, the
plaque-like min-
eral precipitate that builds up in a water
system’s plumbing, reduces the system's
efficiency and elevates maintenance costs.
STI therefore developed a system
that employs three distinct technologies.
The NASA copper/silver ionization process
is the core technology, to which STI added
capabilities for centrifugal separation of
solids from liquids and magnetic field water
modification. Says STI’s Tommy Wood:
“Our systems do an excellent job of
eliminating scale, corrosion, algae, bacteria
and debris from process water, but there is
an additional benefit; because of the NASA
technology we employ, our systems destroy
waterborne bacteria and viruses, including
Legio nella p n mi mopk ila , t h e bac te r i u m
responsible for Legionnaire’s Disease/
The STI Cooling Water Manage-
ment System integrates a pump, the cen-
trifugal solids separator, the copper/silver
biocide generator and magnetic field gener-
ators into a simply installed, easily operable
equipment package that takes up only six
sq u a re fe e t of s pac e i n tn os t a p p 1 i c at i o n s
and totally eliminates the need for water
treatment chemicals and water bleeding.
STI manufactures the system in
three capacities: the ST MOO, ST1-1 100 and
STI-2200 for evaporative cooling systems of
92
up to 400, 1 , 1 00 and 2,200
tons respectively. Larger
systems are custom built
on request*
At far left is the STL
[ 100 unit and in the top left
photo a closeup of the bio-
cide generator (the STI-400
has two pairs of electrodes,
the STI-J 100 three pairs and
the ST1-2200 four pairs).
The copper and silver ions
produced by the generator
kill the algae, bacteria and
vi n i ses i n the wa te r* The
centrifugal separator
removes all waterborne
debris. The magnetic held
generators remove existing
scale, bar further scale
buildup and prevent corro-
sion* At bottom left is a con-
t rol pa n e 1 wi th a glc ived hand
displaying a sample of scale
removed from an industrial
cooling water system.
ST1 systems have
found a wide range of appli-
cations, For example, a sys-
tem is operating on a cool-
iitg lower at General Motors Truck and Bus
Engineering Center, Troy, Michigan; above
right* STI's Jeff Jones is cleaning the pump
strainer basket of a unit installed at the cen-
ter* The GM cooling system was completely
descaled within the first month, corrosion
was eliminated and the water, once rust col-
ored and opaque, is now clear* Other exam-
ples of industrial cooling water installations
are a system in a process cooling tower at
AVX Corporation, Myrtle Beach, South
Carolina* and another in a closed-loop
process cooling system at Canbraco
Industries, also at Myrtle Beach.
Other systems are operating in
amusement parks, to prevent corrosion and
cleanse the water of such facilities as bumper
boat pools and miniature golf ponds; in ice
manufacture, protecting pure water in
atmospheric tanks from bacterial infestation;
and in commercial /residential pools and
spas* where Lhe systems offer chemical
savings and labor savings in addition to
sanitary water* •
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