Tank Size Question

In article <2dhnj010oamfe4u7ph7tvcfdkkg4mjpoom@4ax.com>, Rich Lockyer
<rlockyer@linkline.DONTSPAMME.com> wrote:

€ He was just pulling your lovely leg.

Now, *there's* an image I can sleep with...

--
"We're going to rush the hijackers."
-Jeremy Glick, aboard United Airlines flight 93, September 11, 2001

> If you take 80 cubic feet of air and put it into a cylinder
> the size of a phone booth (remember those?), you would have
> about 15 PSI (ambient). Now take that same air and shove it
> into a coke can and the pressure would be tremendous!

Methinks it wold be a liquid!

> Your 3300 PSI 80 is just a little smaller than the 3000 PSI
> 80. I once got to see an experimental Russian titanium 80
> that was just a little bigger than a football. Of course,
> no regular dive shop could fill it. 6000 PSI is my
> recollection of what it took to fill to 80 cubic feet.
>
> Just my $.02
> --
>
> Ray Contreras
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Once again the Metric system proves to be easier to understand, where the
cylinder is measured by its true volume, irrelevant of pressure, thus a 15L
cylinder has an actual internal volume of 15 Litres. The working pressure
is separated, thus the common cylinder sizes in the UK, Europe & most of the
world are:

1 or 1.5L (Argon suit inflation), generally only available as 200bar
Aluminium.
3L (Pony size)
7L (commonly used for deco gas), or in high pressure steel (300 bar), may be
twinned
10L for shallow single cylinder diving or twined up for smaller divers (like
my wife's twinset)
12L, the most common size for Single-cylinder and for twinning purposes.
15L Often used for slightly deeper single tank diving and twinned for heavy
breathers or deeper (tri-mix) diving.
18 & 20L cylinders are often used for cave diving and the 18L is well known
for its excellent buoyancy characteristics.

The 3L & 7L is available as either aluminium or steel, but the Aluminium
versions are only available in 232bar (approx 3300 psi)
The 7L and 12L steel cylinders are available in both 232 and 300bar (330 &
4000 psi)

As a comparison of sizes:
3L cylinder at 232 bar is roughly equal to 24 CuFt
10L cylinder at 232 bar is roughly equal to 80 CuFt
12L cylinder at 232 bar is roughly equal to 100 CuFt
15L cylinder at 232 bar is roughly equal to 120 CuFt
7L cylinder at 300 bar is equal to 74CuFt
12L cylinder at 300 bar is roughly equal to 127 CuFt

Simple!

In article <chh7j0$p7u$1@sparta.btinternet.com>, TonyH
<tony@samesamediving.com> wrote:

€ Once again the Metric system proves to be easier to understand, where the
€ cylinder is measured by its true volume, irrelevant of pressure, thus a 15L
€ cylinder has an actual internal volume of 15 Litres. The working pressure
€ is separated, thus the common cylinder sizes in the UK, Europe & most of the
€ world are:
€
€ 1 or 1.5L (Argon suit inflation), generally only available as 200bar
€ Aluminium.
€ 3L (Pony size)
€ 7L (commonly used for deco gas), or in high pressure steel (300 bar), may be
€ twinned
€ 10L for shallow single cylinder diving or twined up for smaller divers (like
€ my wife's twinset)
€ 12L, the most common size for Single-cylinder and for twinning purposes.
€ 15L Often used for slightly deeper single tank diving and twinned for heavy
€ breathers or deeper (tri-mix) diving.
€ 18 & 20L cylinders are often used for cave diving and the 18L is well known
€ for its excellent buoyancy characteristics.
€
€ The 3L & 7L is available as either aluminium or steel, but the Aluminium
€ versions are only available in 232bar (approx 3300 psi)
€ The 7L and 12L steel cylinders are available in both 232 and 300bar (330 &
€ 4000 psi)
€
€ As a comparison of sizes:
€ 3L cylinder at 232 bar is roughly equal to 24 CuFt
€ 10L cylinder at 232 bar is roughly equal to 80 CuFt
€ 12L cylinder at 232 bar is roughly equal to 100 CuFt
€ 15L cylinder at 232 bar is roughly equal to 120 CuFt
€ 7L cylinder at 300 bar is equal to 74CuFt
€ 12L cylinder at 300 bar is roughly equal to 127 CuFt
€
€ Simple!


"Simple" doesn't take a page to explain.

"PST 104 cu. feet".

Now that's simple.

--
"We're going to rush the hijackers."
-Jeremy Glick, aboard United Airlines flight 93, September 11, 2001

"Lee Bell" <leebell@ix.remove.netcom.com> wrote in message
news:w2v_c.6796$Wv5.970@newsread3.news.atl.earthli nk.net...
> "Von Fourche" wrote
>
> > I was told at my dive class the aluminum 80 3000 psi was the most
> > popular and standard use tank in the U.S. and Caribbean and general dive
> > industry. Is this true? What about Australia and the Pacific Islands?
>
> It's the most common tank in the US. I'm less certain about its
popularity.
> There are a lot of people that really like low pressure tanks and more
than
> a few that like tanks rated for pressures even higher than the 3,300 psi
you
> asked about.
>
> > I asked my instructor why he uses all aluminum, he said they don't rust
> > as bad, and cheaper too.
>
> They don't rust at all and they're considerably cheaper than comparable
> sized steel tanks.


So, if I was going to buy two or three tanks for personal use, and I
don't mind paying a few hundred dollars more for steel, should I definitely
go with the steel or is it more of a personal choice? No tech diving for
me, just recreational and no deeper than 100 feet.

Also, what are the major companies that make tanks? I've seen mentioned
Cataline and Luxfer. Is one better than the other? Has one company had
more problems (explosive tanks!) than the other?

I was on one online scuba shop, all the steel tanks they sell come with
DIN. Is this standard for all or most steel tanks to use DIN over yoke?

Von Fourche wrote:

>
> So, if I was going to buy two or three tanks for personal use, and I
> don't mind paying a few hundred dollars more for steel, should I definitely
> go with the steel or is it more of a personal choice? No tech diving for
> me, just recreational and no deeper than 100 feet.

At this stage you are only prepared for shallow rec diving. If you are
gonna buy tanks, buy the cheapest you can get (used al 80s, $35).

But why buy tanks at all? If you travel, you won't be carrying them, if
you dive less than 50 local dives a year, it's cheaper to rent them
(purchase + annual vis + hydros + wirebrushing and painting). I own a
couple sets of tanks, but only because I like to be able to go out on
short notice and I don't want to be chasing around for custom fills.

> Also, what are the major companies that make tanks? I've seen mentioned
> Cataline and Luxfer. Is one better than the other? Has one company had
> more problems (explosive tanks!) than the other?

There are several companies that make tanks, none that I know of make
both al and steel (though they sell under a variety of brand names). All
currently manufactured tanks are equal in quality. Some older tanks use
materials no longer acceptable.

> I was on one online scuba shop, all the steel tanks they sell come with
> DIN. Is this standard for all or most steel tanks to use DIN over yoke?

Steels are almost all high pressure, and din is preferred for high
pressure. Some (not all) din valves can be adapted to accept an A-clamp
(yoke).

Never use adapters on any piece of scuba gear. Adapters are for folks
that bought the wrong piece of gear in the first place.

On Mon, 06 Sep 2004 04:45:56 GMT, "Lee Bell"
<leebell@ix.remove.netcom.com> wrote:

>> >compressors? Instead of constantly filling tanks up to 3000 they could
>be
>> >filling tanks up to 2600psi or whatever, and the compressor wouldn't have
>to
>> >work as hard.
>>
>> Yup.
>
>Funny, I could swear my 3,500 psi tanks are steel.

Yup... and about availability now? PST cylinders are harder to find
in SoCal than Neutronium. LDS got one set of double 104/130's in and
said it'll be December before he MAY get another set.

PST was forced to move their factory and has significantly scaled back
on Scuba cylinder production.

Sport Chalet still has a bunch of 3000psi LP 80's (with '02 hydros...
and only 80cf at 3300 under the "plus" hydro) in stock, but the new
tanks are a Norris (Kaiser Steel) 80 that still carries a plus rating,
but fills to 3000psi under the plus.
The thing is as heavy as an old PST LP104.



--- Rich
http://richlockyer.tripod.com/

"Von Fourche" wrote

> So, if I was going to buy two or three tanks for personal use, and I
> don't mind paying a few hundred dollars more for steel, should I
definitely
> go with the steel or is it more of a personal choice? No tech diving for
> me, just recreational and no deeper than 100 feet.

It's really a matter of personal choice. The biggest issues are buoyancy
and trim. Different tanks have different buoyancy characteristics. I have
3,300 psi aluminum Catalina tanks. I like the fact that they are neutral
when empty and, thanks to a lot of years of diving, my relatively low
consumption rate allows me to stay down at moderate depths as long as most
dive operators are willing to wait for me. I have 4 high pressure steel 100
cubic foot tanks. They're still less buoyant, but give me the gas to let me
stay a bit deeper as long as I can stay shallower with the 80s.

> Also, what are the major companies that make tanks? I've seen mentioned
> Cataline and Luxfer. Is one better than the other? Has one company had
> more problems (explosive tanks!) than the other?

Catalina has been a high quality manufacturer from the beginning. Their
tanks have had very few problems. Luxfer is the number one producer of
aluminum tanks. They're also one of the manufacturers that used an inferior
alloy up until about 1988. Since then, they've used the same alloy that
Catalina always did. Luxfers tend to be a few bucks cheaper and a lot
easier to find. I had to order my last two Catalina tanks.

My steel tanks are made by PST. I really like the 232 bar valve on the new
ones. It's convertable, allowing me to use either my Yoke/A Clamp
regulators or my DIN regulators. My older steel tanks are also PST, but
have the old 300 bar valves. They're usable only with my DIN regulators.

> I was on one online scuba shop, all the steel tanks they sell come with
> DIN. Is this standard for all or most steel tanks to use DIN over yoke?

In the US, all high pressure tanks I know of come with DIN valves. I
believe the low pressure steel tanks are available with A clamp, but you'll
have to ask those that prefer them. That's not me.

If you decide on hp steel tanks, check with diversdirect.com. They have
good prices on the new style PST tanks.

Lee

"Rich Lockyer" <rlockyer@linkline.DONTSPAMME.com> wrote in message
news:55dpj0tfot8co6kn78c36u85thtkfkd3sh@4ax.com...
> On Mon, 06 Sep 2004 17:38:34 GMT, "Von Fourche"
> <monaco8292@hotmail.com> wrote:
>
> >go with the steel or is it more of a personal choice? No tech diving for
> >me, just recreational and no deeper than 100 feet.
>
> Just go with a couple of Catalina or Luxfer 3000psi 80's.
> They'll last forever, and when you go on vacation, other than
> compensating for the buoyancy change in your suit, you won't have to
> make any other changes for rental tanks.
>
> The 3300psi 80s are indeed neutral, but that means that you'll need to
> add (somewhere around) 4 pounds for vacation dives, their weight
> distribution/trim may not be the same (meaning you get used to it,
> then end up on vacation with a standard 80 and have trouble keeping
> your feet up or down), and in many places, you may have trouble
> getting a fill to 3300.

All true.