Tanks and valves work together,
so we'll look at them together.Even
a nondiver knows that a scuba
tank is a cylindrical metal
container used to safely store
high-pressure air so you have
something to breathe underwater.
Almost as obvious is the purpose
of the tank valve, which is
to control air flow from the
tank. Sounds simple, but what
you may not realize is that
there are different types of
tanks and valves to handle these
two simple jobs.
Tanks
style and features Tanks come
in a varietv of air capacities,
depending upon their pressure
rating and size. In the metric
system, you express tank capacity
in litres or kilograms of water
capacity. The most common sizes
are 8, 10, 12 and 15 litres. In
the imperial system, you express
capacity in the number of cubic
feet of air you would have if
you released it all at the surface.
The three most common tank sizes
are 50, 71.2 and 80 cubic feet,
although other sizes are available.
The
standard 12 litre/ 71.2 or 80-cubic-foot
tank contains about the same
air you have in a walk-in closet,
compressed into a space about
600 mm/two feet long and 150
mm/half a foot in diameter.
As
this air is compressed into
the tank, its pressure increases.
The pressure in scuba tanks
may be higher than 320 bar/4500
pounds per square inch (psi),
but typical pressure ratings
range from about 170 to 200
bar, or 2250 and 3000 psi.
Scuba tanks are either made
of aluminum or steel. Both types
are subject to regulations usually
established by govern-ment agencies
such as the U.S. Department
of Transportation (DOT), Canadian
Transport Commission (CTC) and
similar agencies in other countries.
Among these regulations, scuba
tanks must pass periodic pressure
tests (discussed below) mandated
by these agencies.
Atlantis International
Bali Dive Center
Jl. By Pass Ngurah Rai #350 Sanur, Bali
Phone : +62-361-284312
Fax : +62-361-282824
Mobile : +62-81-2380 5767
e-mail : info@balidiveaction.com
